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The kexec and crash kernel options are provided in the common
kernel/Kconfig.kexec. Utilize the common options and provide
the ARCH_SUPPORTS_ and ARCH_SELECTS_ entries to recreate the
equivalent set of KEXEC and CRASH options.
Link: https://lkml.kernel.org/r/20230712161545.87870-3-eric.devolder@oracle.com
Signed-off-by: Eric DeVolder <eric.devolder@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
- Add new feature to have function graph tracer record the return value.
Adds a new option: funcgraph-retval ; when set, will show the return
value of a function in the function graph tracer.
- Also add the option: funcgraph-retval-hex where if it is not set, and
the return value is an error code, then it will return the decimal of
the error code, otherwise it still reports the hex value.
- Add the file /sys/kernel/tracing/osnoise/per_cpu/cpu<cpu>/timerlat_fd
That when a application opens it, it becomes the task that the timer lat
tracer traces. The application can also read this file to find out how
it's being interrupted.
- Add the file /sys/kernel/tracing/available_filter_functions_addrs
that works just the same as available_filter_functions but also shows
the addresses of the functions like kallsyms, except that it gives the
address of where the fentry/mcount jump/nop is. This is used by BPF to
make it easier to attach BPF programs to ftrace hooks.
- Replace strlcpy with strscpy in the tracing boot code.
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Merge tag 'trace-v6.5' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace
Pull tracing updates from Steven Rostedt:
- Add new feature to have function graph tracer record the return
value. Adds a new option: funcgraph-retval ; when set, will show the
return value of a function in the function graph tracer.
- Also add the option: funcgraph-retval-hex where if it is not set, and
the return value is an error code, then it will return the decimal of
the error code, otherwise it still reports the hex value.
- Add the file /sys/kernel/tracing/osnoise/per_cpu/cpu<cpu>/timerlat_fd
That when a application opens it, it becomes the task that the timer
lat tracer traces. The application can also read this file to find
out how it's being interrupted.
- Add the file /sys/kernel/tracing/available_filter_functions_addrs
that works just the same as available_filter_functions but also shows
the addresses of the functions like kallsyms, except that it gives
the address of where the fentry/mcount jump/nop is. This is used by
BPF to make it easier to attach BPF programs to ftrace hooks.
- Replace strlcpy with strscpy in the tracing boot code.
* tag 'trace-v6.5' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace:
tracing: Fix warnings when building htmldocs for function graph retval
riscv: ftrace: Enable HAVE_FUNCTION_GRAPH_RETVAL
tracing/boot: Replace strlcpy with strscpy
tracing/timerlat: Add user-space interface
tracing/osnoise: Skip running osnoise if all instances are off
tracing/osnoise: Switch from PF_NO_SETAFFINITY to migrate_disable
ftrace: Show all functions with addresses in available_filter_functions_addrs
selftests/ftrace: Add funcgraph-retval test case
LoongArch: ftrace: Enable HAVE_FUNCTION_GRAPH_RETVAL
x86/ftrace: Enable HAVE_FUNCTION_GRAPH_RETVAL
arm64: ftrace: Enable HAVE_FUNCTION_GRAPH_RETVAL
tracing: Add documentation for funcgraph-retval and funcgraph-retval-hex
function_graph: Support recording and printing the return value of function
fgraph: Add declaration of "struct fgraph_ret_regs"
This modifies our user mode stack expansion code to always take the
mmap_lock for writing before modifying the VM layout.
It's actually something we always technically should have done, but
because we didn't strictly need it, we were being lazy ("opportunistic"
sounds so much better, doesn't it?) about things, and had this hack in
place where we would extend the stack vma in-place without doing the
proper locking.
And it worked fine. We just needed to change vm_start (or, in the case
of grow-up stacks, vm_end) and together with some special ad-hoc locking
using the anon_vma lock and the mm->page_table_lock, it all was fairly
straightforward.
That is, it was all fine until Ruihan Li pointed out that now that the
vma layout uses the maple tree code, we *really* don't just change
vm_start and vm_end any more, and the locking really is broken. Oops.
It's not actually all _that_ horrible to fix this once and for all, and
do proper locking, but it's a bit painful. We have basically three
different cases of stack expansion, and they all work just a bit
differently:
- the common and obvious case is the page fault handling. It's actually
fairly simple and straightforward, except for the fact that we have
something like 24 different versions of it, and you end up in a maze
of twisty little passages, all alike.
- the simplest case is the execve() code that creates a new stack.
There are no real locking concerns because it's all in a private new
VM that hasn't been exposed to anybody, but lockdep still can end up
unhappy if you get it wrong.
- and finally, we have GUP and page pinning, which shouldn't really be
expanding the stack in the first place, but in addition to execve()
we also use it for ptrace(). And debuggers do want to possibly access
memory under the stack pointer and thus need to be able to expand the
stack as a special case.
None of these cases are exactly complicated, but the page fault case in
particular is just repeated slightly differently many many times. And
ia64 in particular has a fairly complicated situation where you can have
both a regular grow-down stack _and_ a special grow-up stack for the
register backing store.
So to make this slightly more manageable, the bulk of this series is to
first create a helper function for the most common page fault case, and
convert all the straightforward architectures to it.
Thus the new 'lock_mm_and_find_vma()' helper function, which ends up
being used by x86, arm, powerpc, mips, riscv, alpha, arc, csky, hexagon,
loongarch, nios2, sh, sparc32, and xtensa. So we not only convert more
than half the architectures, we now have more shared code and avoid some
of those twisty little passages.
And largely due to this common helper function, the full diffstat of
this series ends up deleting more lines than it adds.
That still leaves eight architectures (ia64, m68k, microblaze, openrisc,
parisc, s390, sparc64 and um) that end up doing 'expand_stack()'
manually because they are doing something slightly different from the
normal pattern. Along with the couple of special cases in execve() and
GUP.
So there's a couple of patches that first create 'locked' helper
versions of the stack expansion functions, so that there's a obvious
path forward in the conversion. The execve() case is then actually
pretty simple, and is a nice cleanup from our old "grow-up stackls are
special, because at execve time even they grow down".
The #ifdef CONFIG_STACK_GROWSUP in that code just goes away, because
it's just more straightforward to write out the stack expansion there
manually, instead od having get_user_pages_remote() do it for us in some
situations but not others and have to worry about locking rules for GUP.
And the final step is then to just convert the remaining odd cases to a
new world order where 'expand_stack()' is called with the mmap_lock held
for reading, but where it might drop it and upgrade it to a write, only
to return with it held for reading (in the success case) or with it
completely dropped (in the failure case).
In the process, we remove all the stack expansion from GUP (where
dropping the lock wouldn't be ok without special rules anyway), and add
it in manually to __access_remote_vm() for ptrace().
Thanks to Adrian Glaubitz and Frank Scheiner who tested the ia64 cases.
Everything else here felt pretty straightforward, but the ia64 rules for
stack expansion are really quite odd and very different from everything
else. Also thanks to Vegard Nossum who caught me getting one of those
odd conditions entirely the wrong way around.
Anyway, I think I want to actually move all the stack expansion code to
a whole new file of its own, rather than have it split up between
mm/mmap.c and mm/memory.c, but since this will have to be backported to
the initial maple tree vma introduction anyway, I tried to keep the
patches _fairly_ minimal.
Also, while I don't think it's valid to expand the stack from GUP, the
final patch in here is a "warn if some crazy GUP user wants to try to
expand the stack" patch. That one will be reverted before the final
release, but it's left to catch any odd cases during the merge window
and release candidates.
Reported-by: Ruihan Li <lrh2000@pku.edu.cn>
* branch 'expand-stack':
gup: add warning if some caller would seem to want stack expansion
mm: always expand the stack with the mmap write lock held
execve: expand new process stack manually ahead of time
mm: make find_extend_vma() fail if write lock not held
powerpc/mm: convert coprocessor fault to lock_mm_and_find_vma()
mm/fault: convert remaining simple cases to lock_mm_and_find_vma()
arm/mm: Convert to using lock_mm_and_find_vma()
riscv/mm: Convert to using lock_mm_and_find_vma()
mips/mm: Convert to using lock_mm_and_find_vma()
powerpc/mm: Convert to using lock_mm_and_find_vma()
arm64/mm: Convert to using lock_mm_and_find_vma()
mm: make the page fault mmap locking killable
mm: introduce new 'lock_mm_and_find_vma()' page fault helper
and assert __x86_return_thunk's alignment so that future changes to
the symbol macros do not accidentally break them.
- Remove CONFIG_X86_FEATURE_NAMES Kconfig option as its existence is
pointless
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Merge tag 'x86_cpu_for_v6.5' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 cpu updates from Borislav Petkov:
- Compute the purposeful misalignment of zen_untrain_ret automatically
and assert __x86_return_thunk's alignment so that future changes to
the symbol macros do not accidentally break them.
- Remove CONFIG_X86_FEATURE_NAMES Kconfig option as its existence is
pointless
* tag 'x86_cpu_for_v6.5' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/retbleed: Add __x86_return_thunk alignment checks
x86/cpu: Remove X86_FEATURE_NAMES
x86/Kconfig: Make X86_FEATURE_NAMES non-configurable in prompt
The gist of it all is that Intel TDX and AMD SEV-SNP confidential
computing guests define the notion of accepting memory before using it
and thus preventing a whole set of attacks against such guests like
memory replay and the like.
There are a couple of strategies of how memory should be accepted
- the current implementation does an on-demand way of accepting.
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Merge tag 'x86_cc_for_v6.5' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 confidential computing update from Borislav Petkov:
- Add support for unaccepted memory as specified in the UEFI spec v2.9.
The gist of it all is that Intel TDX and AMD SEV-SNP confidential
computing guests define the notion of accepting memory before using
it and thus preventing a whole set of attacks against such guests
like memory replay and the like.
There are a couple of strategies of how memory should be accepted -
the current implementation does an on-demand way of accepting.
* tag 'x86_cc_for_v6.5' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
virt: sevguest: Add CONFIG_CRYPTO dependency
x86/efi: Safely enable unaccepted memory in UEFI
x86/sev: Add SNP-specific unaccepted memory support
x86/sev: Use large PSC requests if applicable
x86/sev: Allow for use of the early boot GHCB for PSC requests
x86/sev: Put PSC struct on the stack in prep for unaccepted memory support
x86/sev: Fix calculation of end address based on number of pages
x86/tdx: Add unaccepted memory support
x86/tdx: Refactor try_accept_one()
x86/tdx: Make _tdx_hypercall() and __tdx_module_call() available in boot stub
efi/unaccepted: Avoid load_unaligned_zeropad() stepping into unaccepted memory
efi: Add unaccepted memory support
x86/boot/compressed: Handle unaccepted memory
efi/libstub: Implement support for unaccepted memory
efi/x86: Get full memory map in allocate_e820()
mm: Add support for unaccepted memory
- Parallel CPU bringup
The reason why people are interested in parallel bringup is to shorten
the (kexec) reboot time of cloud servers to reduce the downtime of the
VM tenants.
The current fully serialized bringup does the following per AP:
1) Prepare callbacks (allocate, intialize, create threads)
2) Kick the AP alive (e.g. INIT/SIPI on x86)
3) Wait for the AP to report alive state
4) Let the AP continue through the atomic bringup
5) Let the AP run the threaded bringup to full online state
There are two significant delays:
#3 The time for an AP to report alive state in start_secondary() on
x86 has been measured in the range between 350us and 3.5ms
depending on vendor and CPU type, BIOS microcode size etc.
#4 The atomic bringup does the microcode update. This has been
measured to take up to ~8ms on the primary threads depending on
the microcode patch size to apply.
On a two socket SKL server with 56 cores (112 threads) the boot CPU
spends on current mainline about 800ms busy waiting for the APs to come
up and apply microcode. That's more than 80% of the actual onlining
procedure.
This can be reduced significantly by splitting the bringup mechanism
into two parts:
1) Run the prepare callbacks and kick the AP alive for each AP which
needs to be brought up.
The APs wake up, do their firmware initialization and run the low
level kernel startup code including microcode loading in parallel
up to the first synchronization point. (#1 and #2 above)
2) Run the rest of the bringup code strictly serialized per CPU
(#3 - #5 above) as it's done today.
Parallelizing that stage of the CPU bringup might be possible in
theory, but it's questionable whether required surgery would be
justified for a pretty small gain.
If the system is large enough the first AP is already waiting at the
first synchronization point when the boot CPU finished the wake-up of
the last AP. That reduces the AP bringup time on that SKL from ~800ms
to ~80ms, i.e. by a factor ~10x.
The actual gain varies wildly depending on the system, CPU, microcode
patch size and other factors. There are some opportunities to reduce
the overhead further, but that needs some deep surgery in the x86 CPU
bringup code.
For now this is only enabled on x86, but the core functionality
obviously works for all SMP capable architectures.
- Enhancements for SMP function call tracing so it is possible to locate
the scheduling and the actual execution points. That allows to measure
IPI delivery time precisely.
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Merge tag 'smp-core-2023-06-26' of ssh://gitolite.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull SMP updates from Thomas Gleixner:
"A large update for SMP management:
- Parallel CPU bringup
The reason why people are interested in parallel bringup is to
shorten the (kexec) reboot time of cloud servers to reduce the
downtime of the VM tenants.
The current fully serialized bringup does the following per AP:
1) Prepare callbacks (allocate, intialize, create threads)
2) Kick the AP alive (e.g. INIT/SIPI on x86)
3) Wait for the AP to report alive state
4) Let the AP continue through the atomic bringup
5) Let the AP run the threaded bringup to full online state
There are two significant delays:
#3 The time for an AP to report alive state in start_secondary()
on x86 has been measured in the range between 350us and 3.5ms
depending on vendor and CPU type, BIOS microcode size etc.
#4 The atomic bringup does the microcode update. This has been
measured to take up to ~8ms on the primary threads depending
on the microcode patch size to apply.
On a two socket SKL server with 56 cores (112 threads) the boot CPU
spends on current mainline about 800ms busy waiting for the APs to
come up and apply microcode. That's more than 80% of the actual
onlining procedure.
This can be reduced significantly by splitting the bringup
mechanism into two parts:
1) Run the prepare callbacks and kick the AP alive for each AP
which needs to be brought up.
The APs wake up, do their firmware initialization and run the
low level kernel startup code including microcode loading in
parallel up to the first synchronization point. (#1 and #2
above)
2) Run the rest of the bringup code strictly serialized per CPU
(#3 - #5 above) as it's done today.
Parallelizing that stage of the CPU bringup might be possible
in theory, but it's questionable whether required surgery
would be justified for a pretty small gain.
If the system is large enough the first AP is already waiting at
the first synchronization point when the boot CPU finished the
wake-up of the last AP. That reduces the AP bringup time on that
SKL from ~800ms to ~80ms, i.e. by a factor ~10x.
The actual gain varies wildly depending on the system, CPU,
microcode patch size and other factors. There are some
opportunities to reduce the overhead further, but that needs some
deep surgery in the x86 CPU bringup code.
For now this is only enabled on x86, but the core functionality
obviously works for all SMP capable architectures.
- Enhancements for SMP function call tracing so it is possible to
locate the scheduling and the actual execution points. That allows
to measure IPI delivery time precisely"
* tag 'smp-core-2023-06-26' of ssh://gitolite.kernel.org/pub/scm/linux/kernel/git/tip/tip: (45 commits)
trace,smp: Add tracepoints for scheduling remotelly called functions
trace,smp: Add tracepoints around remotelly called functions
MAINTAINERS: Add CPU HOTPLUG entry
x86/smpboot: Fix the parallel bringup decision
x86/realmode: Make stack lock work in trampoline_compat()
x86/smp: Initialize cpu_primary_thread_mask late
cpu/hotplug: Fix off by one in cpuhp_bringup_mask()
x86/apic: Fix use of X{,2}APIC_ENABLE in asm with older binutils
x86/smpboot/64: Implement arch_cpuhp_init_parallel_bringup() and enable it
x86/smpboot: Support parallel startup of secondary CPUs
x86/smpboot: Implement a bit spinlock to protect the realmode stack
x86/apic: Save the APIC virtual base address
cpu/hotplug: Allow "parallel" bringup up to CPUHP_BP_KICK_AP_STATE
x86/apic: Provide cpu_primary_thread mask
x86/smpboot: Enable split CPU startup
cpu/hotplug: Provide a split up CPUHP_BRINGUP mechanism
cpu/hotplug: Reset task stack state in _cpu_up()
cpu/hotplug: Remove unused state functions
riscv: Switch to hotplug core state synchronization
parisc: Switch to hotplug core state synchronization
...
.. and make x86 use it.
This basically extracts the existing x86 "find and expand faulting vma"
code, but extends it to also take the mmap lock for writing in case we
actually do need to expand the vma.
We've historically short-circuited that case, and have some rather ugly
special logic to serialize the stack segment expansion (since we only
hold the mmap lock for reading) that doesn't match the normal VM
locking.
That slight violation of locking worked well, right up until it didn't:
the maple tree code really does want proper locking even for simple
extension of an existing vma.
So extract the code for "look up the vma of the fault" from x86, fix it
up to do the necessary write locking, and make it available as a helper
function for other architectures that can use the common helper.
Note: I say "common helper", but it really only handles the normal
stack-grows-down case. Which is all architectures except for PA-RISC
and IA64. So some rare architectures can't use the helper, but if they
care they'll just need to open-code this logic.
It's also worth pointing out that this code really would like to have an
optimistic "mmap_upgrade_trylock()" to make it quicker to go from a
read-lock (for the common case) to taking the write lock (for having to
extend the vma) in the normal single-threaded situation where there is
no other locking activity.
But that _is_ all the very uncommon special case, so while it would be
nice to have such an operation, it probably doesn't matter in reality.
I did put in the skeleton code for such a possible future expansion,
even if it only acts as pseudo-documentation for what we're doing.
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The previous patch ("function_graph: Support recording and printing
the return value of function") has laid the groundwork for the for
the funcgraph-retval, and this modification makes it available on
the x86 platform.
We introduce a new structure called fgraph_ret_regs for the x86
platform to hold return registers and the frame pointer. We then
fill its content in the return_to_handler and pass its address
to the function ftrace_return_to_handler to record the return
value.
Link: https://lkml.kernel.org/r/53a506f0f18ff4b7aeb0feb762f1c9a5e9b83ee9.1680954589.git.pengdonglin@sangfor.com.cn
Signed-off-by: Donglin Peng <pengdonglin@sangfor.com.cn>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
check_bugs() is a dumping ground for finalizing the CPU bringup. Only parts of
it has to do with actual CPU bugs.
Split it apart into arch_cpu_finalize_init() and cpu_select_mitigations().
Fixup the bogus 32bit comments while at it.
No functional change.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Borislav Petkov (AMD) <bp@alien8.de>
Link: https://lore.kernel.org/r/20230613224545.019583869@linutronix.de
Add SNP-specific hooks to the unaccepted memory support in the boot
path (__accept_memory()) and the core kernel (accept_memory()) in order
to support booting SNP guests when unaccepted memory is present. Without
this support, SNP guests will fail to boot and/or panic() when unaccepted
memory is present in the EFI memory map.
The process of accepting memory under SNP involves invoking the hypervisor
to perform a page state change for the page to private memory and then
issuing a PVALIDATE instruction to accept the page.
Since the boot path and the core kernel paths perform similar operations,
move the pvalidate_pages() and vmgexit_psc() functions into sev-shared.c
to avoid code duplication.
Create the new header file arch/x86/boot/compressed/sev.h because adding
the function declaration to any of the existing SEV related header files
pulls in too many other header files, causing the build to fail.
Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Link: https://lore.kernel.org/r/a52fa69f460fd1876d70074b20ad68210dfc31dd.1686063086.git.thomas.lendacky@amd.com
Hookup TDX-specific code to accept memory.
Accepting the memory is done with ACCEPT_PAGE module call on every page
in the range. MAP_GPA hypercall is not required as the unaccepted memory
is considered private already.
Extract the part of tdx_enc_status_changed() that does memory acceptance
in a new helper. Move the helper tdx-shared.c. It is going to be used by
both main kernel and decompressor.
[ bp: Fix the INTEL_TDX_GUEST=y, KVM_GUEST=n build. ]
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Link: https://lore.kernel.org/r/20230606142637.5171-10-kirill.shutemov@linux.intel.com
While discussing to change the visibility of X86_FEATURE_NAMES (see Link)
in order to remove CONFIG_EMBEDDED, Boris suggested to simply make the
X86_FEATURE_NAMES functionality unconditional.
As the need for really tiny kernel images has gone away and kernel images
with !X86_FEATURE_NAMES are hardly tested, remove this config and the whole
ifdeffery in the source code.
Suggested-by: Borislav Petkov <bp@alien8.de>
Signed-off-by: Lukas Bulwahn <lukas.bulwahn@gmail.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Link: https://lore.kernel.org/all/20230509084007.24373-1-lukas.bulwahn@gmail.com/
Link: https://lore.kernel.org/r/20230510065713.10996-3-lukas.bulwahn@gmail.com
While discussing to change the visibility of X86_FEATURE_NAMES (see Link)
in order to remove CONFIG_EMBEDDED, Boris suggested to simply make the
X86_FEATURE_NAMES functionality unconditional.
As a first step, make X86_FEATURE_NAMES disappear from Kconfig. So, as
X86_FEATURE_NAMES defaults to yes, to disable it, one now needs to
modify the .config file before compiling the kernel.
Suggested-by: Borislav Petkov <bp@alien8.de>
Signed-off-by: Lukas Bulwahn <lukas.bulwahn@gmail.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Link: https://lore.kernel.org/all/20230509084007.24373-1-lukas.bulwahn@gmail.com/
Implement the validation function which tells the core code whether
parallel bringup is possible.
The only condition for now is that the kernel does not run in an encrypted
guest as these will trap the RDMSR via #VC, which cannot be handled at that
point in early startup.
There was an earlier variant for AMD-SEV which used the GHBC protocol for
retrieving the APIC ID via CPUID, but there is no guarantee that the
initial APIC ID in CPUID is the same as the real APIC ID. There is no
enforcement from the secure firmware and the hypervisor can assign APIC IDs
as it sees fit as long as the ACPI/MADT table is consistent with that
assignment.
Unfortunately there is no RDMSR GHCB protocol at the moment, so enabling
AMD-SEV guests for parallel startup needs some more thought.
Intel-TDX provides a secure RDMSR hypercall, but supporting that is outside
the scope of this change.
Fixup announce_cpu() as e.g. on Hyper-V CPU1 is the secondary sibling of
CPU0, which makes the @cpu == 1 logic in announce_cpu() fall apart.
[ mikelley: Reported the announce_cpu() fallout
Originally-by: David Woodhouse <dwmw@amazon.co.uk>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Tested-by: Michael Kelley <mikelley@microsoft.com>
Tested-by: Oleksandr Natalenko <oleksandr@natalenko.name>
Tested-by: Helge Deller <deller@gmx.de> # parisc
Tested-by: Guilherme G. Piccoli <gpiccoli@igalia.com> # Steam Deck
Link: https://lore.kernel.org/r/20230512205257.467571745@linutronix.de
The x86 CPU bringup state currently does AP wake-up, wait for AP to
respond and then release it for full bringup.
It is safe to be split into a wake-up and and a separate wait+release
state.
Provide the required functions and enable the split CPU bringup, which
prepares for parallel bringup, where the bringup of the non-boot CPUs takes
two iterations: One to prepare and wake all APs and the second to wait and
release them. Depending on timing this can eliminate the wait time
completely.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Tested-by: Michael Kelley <mikelley@microsoft.com>
Tested-by: Oleksandr Natalenko <oleksandr@natalenko.name>
Tested-by: Helge Deller <deller@gmx.de> # parisc
Tested-by: Guilherme G. Piccoli <gpiccoli@igalia.com> # Steam Deck
Link: https://lore.kernel.org/r/20230512205257.133453992@linutronix.de
The new AP state tracking and synchronization mechanism in the CPU hotplug
core code allows to remove quite some x86 specific code:
1) The AP alive synchronization based on cpumasks
2) The decision whether an AP can be brought up again
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Tested-by: Michael Kelley <mikelley@microsoft.com>
Tested-by: Oleksandr Natalenko <oleksandr@natalenko.name>
Tested-by: Helge Deller <deller@gmx.de> # parisc
Tested-by: Guilherme G. Piccoli <gpiccoli@igalia.com> # Steam Deck
Link: https://lore.kernel.org/r/20230512205256.529657366@linutronix.de
This was introduced together with commit e1c467e69040 ("x86, hotplug: Wake
up CPU0 via NMI instead of INIT, SIPI, SIPI") to eventually support
physical hotplug of CPU0:
"We'll change this code in the future to wake up hard offlined CPU0 if
real platform and request are available."
11 years later this has not happened and physical hotplug is not officially
supported. Remove the cruft.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Tested-by: Michael Kelley <mikelley@microsoft.com>
Tested-by: Oleksandr Natalenko <oleksandr@natalenko.name>
Tested-by: Helge Deller <deller@gmx.de> # parisc
Tested-by: Guilherme G. Piccoli <gpiccoli@igalia.com> # Steam Deck
Link: https://lore.kernel.org/r/20230512205255.715707999@linutronix.de
to ARM's Top Byte Ignore and allows userspace to store metadata in some
bits of pointers without masking it out before use.
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Merge tag 'x86_mm_for_6.4' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 LAM (Linear Address Masking) support from Dave Hansen:
"Add support for the new Linear Address Masking CPU feature.
This is similar to ARM's Top Byte Ignore and allows userspace to store
metadata in some bits of pointers without masking it out before use"
* tag 'x86_mm_for_6.4' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/mm/iommu/sva: Do not allow to set FORCE_TAGGED_SVA bit from outside
x86/mm/iommu/sva: Fix error code for LAM enabling failure due to SVA
selftests/x86/lam: Add test cases for LAM vs thread creation
selftests/x86/lam: Add ARCH_FORCE_TAGGED_SVA test cases for linear-address masking
selftests/x86/lam: Add inherit test cases for linear-address masking
selftests/x86/lam: Add io_uring test cases for linear-address masking
selftests/x86/lam: Add mmap and SYSCALL test cases for linear-address masking
selftests/x86/lam: Add malloc and tag-bits test cases for linear-address masking
x86/mm/iommu/sva: Make LAM and SVA mutually exclusive
iommu/sva: Replace pasid_valid() helper with mm_valid_pasid()
mm: Expose untagging mask in /proc/$PID/status
x86/mm: Provide arch_prctl() interface for LAM
x86/mm: Reduce untagged_addr() overhead for systems without LAM
x86/uaccess: Provide untagged_addr() and remove tags before address check
mm: Introduce untagged_addr_remote()
x86/mm: Handle LAM on context switch
x86: CPUID and CR3/CR4 flags for Linear Address Masking
x86: Allow atomic MM_CONTEXT flags setting
x86/mm: Rework address range check in get_user() and put_user()
switching from a user process to a kernel thread.
- More folio conversions from Kefeng Wang, Zhang Peng and Pankaj Raghav.
- zsmalloc performance improvements from Sergey Senozhatsky.
- Yue Zhao has found and fixed some data race issues around the
alteration of memcg userspace tunables.
- VFS rationalizations from Christoph Hellwig:
- removal of most of the callers of write_one_page().
- make __filemap_get_folio()'s return value more useful
- Luis Chamberlain has changed tmpfs so it no longer requires swap
backing. Use `mount -o noswap'.
- Qi Zheng has made the slab shrinkers operate locklessly, providing
some scalability benefits.
- Keith Busch has improved dmapool's performance, making part of its
operations O(1) rather than O(n).
- Peter Xu adds the UFFD_FEATURE_WP_UNPOPULATED feature to userfaultd,
permitting userspace to wr-protect anon memory unpopulated ptes.
- Kirill Shutemov has changed MAX_ORDER's meaning to be inclusive rather
than exclusive, and has fixed a bunch of errors which were caused by its
unintuitive meaning.
- Axel Rasmussen give userfaultfd the UFFDIO_CONTINUE_MODE_WP feature,
which causes minor faults to install a write-protected pte.
- Vlastimil Babka has done some maintenance work on vma_merge():
cleanups to the kernel code and improvements to our userspace test
harness.
- Cleanups to do_fault_around() by Lorenzo Stoakes.
- Mike Rapoport has moved a lot of initialization code out of various
mm/ files and into mm/mm_init.c.
- Lorenzo Stoakes removd vmf_insert_mixed_prot(), which was added for
DRM, but DRM doesn't use it any more.
- Lorenzo has also coverted read_kcore() and vread() to use iterators
and has thereby removed the use of bounce buffers in some cases.
- Lorenzo has also contributed further cleanups of vma_merge().
- Chaitanya Prakash provides some fixes to the mmap selftesting code.
- Matthew Wilcox changes xfs and afs so they no longer take sleeping
locks in ->map_page(), a step towards RCUification of pagefaults.
- Suren Baghdasaryan has improved mmap_lock scalability by switching to
per-VMA locking.
- Frederic Weisbecker has reworked the percpu cache draining so that it
no longer causes latency glitches on cpu isolated workloads.
- Mike Rapoport cleans up and corrects the ARCH_FORCE_MAX_ORDER Kconfig
logic.
- Liu Shixin has changed zswap's initialization so we no longer waste a
chunk of memory if zswap is not being used.
- Yosry Ahmed has improved the performance of memcg statistics flushing.
- David Stevens has fixed several issues involving khugepaged,
userfaultfd and shmem.
- Christoph Hellwig has provided some cleanup work to zram's IO-related
code paths.
- David Hildenbrand has fixed up some issues in the selftest code's
testing of our pte state changing.
- Pankaj Raghav has made page_endio() unneeded and has removed it.
- Peter Xu contributed some rationalizations of the userfaultfd
selftests.
- Yosry Ahmed has fixed an issue around memcg's page recalim accounting.
- Chaitanya Prakash has fixed some arm-related issues in the
selftests/mm code.
- Longlong Xia has improved the way in which KSM handles hwpoisoned
pages.
- Peter Xu fixes a few issues with uffd-wp at fork() time.
- Stefan Roesch has changed KSM so that it may now be used on a
per-process and per-cgroup basis.
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Merge tag 'mm-stable-2023-04-27-15-30' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
Pull MM updates from Andrew Morton:
- Nick Piggin's "shoot lazy tlbs" series, to improve the peformance of
switching from a user process to a kernel thread.
- More folio conversions from Kefeng Wang, Zhang Peng and Pankaj
Raghav.
- zsmalloc performance improvements from Sergey Senozhatsky.
- Yue Zhao has found and fixed some data race issues around the
alteration of memcg userspace tunables.
- VFS rationalizations from Christoph Hellwig:
- removal of most of the callers of write_one_page()
- make __filemap_get_folio()'s return value more useful
- Luis Chamberlain has changed tmpfs so it no longer requires swap
backing. Use `mount -o noswap'.
- Qi Zheng has made the slab shrinkers operate locklessly, providing
some scalability benefits.
- Keith Busch has improved dmapool's performance, making part of its
operations O(1) rather than O(n).
- Peter Xu adds the UFFD_FEATURE_WP_UNPOPULATED feature to userfaultd,
permitting userspace to wr-protect anon memory unpopulated ptes.
- Kirill Shutemov has changed MAX_ORDER's meaning to be inclusive
rather than exclusive, and has fixed a bunch of errors which were
caused by its unintuitive meaning.
- Axel Rasmussen give userfaultfd the UFFDIO_CONTINUE_MODE_WP feature,
which causes minor faults to install a write-protected pte.
- Vlastimil Babka has done some maintenance work on vma_merge():
cleanups to the kernel code and improvements to our userspace test
harness.
- Cleanups to do_fault_around() by Lorenzo Stoakes.
- Mike Rapoport has moved a lot of initialization code out of various
mm/ files and into mm/mm_init.c.
- Lorenzo Stoakes removd vmf_insert_mixed_prot(), which was added for
DRM, but DRM doesn't use it any more.
- Lorenzo has also coverted read_kcore() and vread() to use iterators
and has thereby removed the use of bounce buffers in some cases.
- Lorenzo has also contributed further cleanups of vma_merge().
- Chaitanya Prakash provides some fixes to the mmap selftesting code.
- Matthew Wilcox changes xfs and afs so they no longer take sleeping
locks in ->map_page(), a step towards RCUification of pagefaults.
- Suren Baghdasaryan has improved mmap_lock scalability by switching to
per-VMA locking.
- Frederic Weisbecker has reworked the percpu cache draining so that it
no longer causes latency glitches on cpu isolated workloads.
- Mike Rapoport cleans up and corrects the ARCH_FORCE_MAX_ORDER Kconfig
logic.
- Liu Shixin has changed zswap's initialization so we no longer waste a
chunk of memory if zswap is not being used.
- Yosry Ahmed has improved the performance of memcg statistics
flushing.
- David Stevens has fixed several issues involving khugepaged,
userfaultfd and shmem.
- Christoph Hellwig has provided some cleanup work to zram's IO-related
code paths.
- David Hildenbrand has fixed up some issues in the selftest code's
testing of our pte state changing.
- Pankaj Raghav has made page_endio() unneeded and has removed it.
- Peter Xu contributed some rationalizations of the userfaultfd
selftests.
- Yosry Ahmed has fixed an issue around memcg's page recalim
accounting.
- Chaitanya Prakash has fixed some arm-related issues in the
selftests/mm code.
- Longlong Xia has improved the way in which KSM handles hwpoisoned
pages.
- Peter Xu fixes a few issues with uffd-wp at fork() time.
- Stefan Roesch has changed KSM so that it may now be used on a
per-process and per-cgroup basis.
* tag 'mm-stable-2023-04-27-15-30' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (369 commits)
mm,unmap: avoid flushing TLB in batch if PTE is inaccessible
shmem: restrict noswap option to initial user namespace
mm/khugepaged: fix conflicting mods to collapse_file()
sparse: remove unnecessary 0 values from rc
mm: move 'mmap_min_addr' logic from callers into vm_unmapped_area()
hugetlb: pte_alloc_huge() to replace huge pte_alloc_map()
maple_tree: fix allocation in mas_sparse_area()
mm: do not increment pgfault stats when page fault handler retries
zsmalloc: allow only one active pool compaction context
selftests/mm: add new selftests for KSM
mm: add new KSM process and sysfs knobs
mm: add new api to enable ksm per process
mm: shrinkers: fix debugfs file permissions
mm: don't check VMA write permissions if the PTE/PMD indicates write permissions
migrate_pages_batch: fix statistics for longterm pin retry
userfaultfd: use helper function range_in_vma()
lib/show_mem.c: use for_each_populated_zone() simplify code
mm: correct arg in reclaim_pages()/reclaim_clean_pages_from_list()
fs/buffer: convert create_page_buffers to folio_create_buffers
fs/buffer: add folio_create_empty_buffers helper
...
These are various cleanups, fixing a number of uapi header files to no
longer reference CONFIG_* symbols, and one patch that introduces the
new CONFIG_HAS_IOPORT symbol for architectures that provide working
inb()/outb() macros, as a preparation for adding driver dependencies
on those in the following release.
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Merge tag 'asm-generic-6.4' of git://git.kernel.org/pub/scm/linux/kernel/git/arnd/asm-generic
Pull asm-generic updates from Arnd Bergmann:
"These are various cleanups, fixing a number of uapi header files to no
longer reference CONFIG_* symbols, and one patch that introduces the
new CONFIG_HAS_IOPORT symbol for architectures that provide working
inb()/outb() macros, as a preparation for adding driver dependencies
on those in the following release"
* tag 'asm-generic-6.4' of git://git.kernel.org/pub/scm/linux/kernel/git/arnd/asm-generic:
Kconfig: introduce HAS_IOPORT option and select it as necessary
scripts: Update the CONFIG_* ignore list in headers_install.sh
pktcdvd: Remove CONFIG_CDROM_PKTCDVD_WCACHE from uapi header
Move bp_type_idx to include/linux/hw_breakpoint.h
Move ep_take_care_of_epollwakeup() to fs/eventpoll.c
Move COMPAT_ATM_ADDPARTY to net/atm/svc.c
still a fair amount going on, including:
- Reorganizing the architecture-specific documentation under
Documentation/arch. This makes the structure match the source directory
and helps to clean up the mess that is the top-level Documentation
directory a bit. This work creates the new directory and moves x86 and
most of the less-active architectures there. The current plan is to move
the rest of the architectures in 6.5, with the patches going through the
appropriate subsystem trees.
- Some more Spanish translations and maintenance of the Italian
translation.
- A new "Kernel contribution maturity model" document from Ted.
- A new tutorial on quickly building a trimmed kernel from Thorsten.
Plus the usual set of updates and fixes.
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Merge tag 'docs-6.4' of git://git.lwn.net/linux
Pull documentation updates from Jonathan Corbet:
"Commit volume in documentation is relatively low this time, but there
is still a fair amount going on, including:
- Reorganize the architecture-specific documentation under
Documentation/arch
This makes the structure match the source directory and helps to
clean up the mess that is the top-level Documentation directory a
bit. This work creates the new directory and moves x86 and most of
the less-active architectures there.
The current plan is to move the rest of the architectures in 6.5,
with the patches going through the appropriate subsystem trees.
- Some more Spanish translations and maintenance of the Italian
translation
- A new "Kernel contribution maturity model" document from Ted
- A new tutorial on quickly building a trimmed kernel from Thorsten
Plus the usual set of updates and fixes"
* tag 'docs-6.4' of git://git.lwn.net/linux: (47 commits)
media: Adjust column width for pdfdocs
media: Fix building pdfdocs
docs: clk: add documentation to log which clocks have been disabled
docs: trace: Fix typo in ftrace.rst
Documentation/process: always CC responsible lists
docs: kmemleak: adjust to config renaming
ELF: document some de-facto PT_* ABI quirks
Documentation: arm: remove stih415/stih416 related entries
docs: turn off "smart quotes" in the HTML build
Documentation: firmware: Clarify firmware path usage
docs/mm: Physical Memory: Fix grammar
Documentation: Add document for false sharing
dma-api-howto: typo fix
docs: move m68k architecture documentation under Documentation/arch/
docs: move parisc documentation under Documentation/arch/
docs: move ia64 architecture docs under Documentation/arch/
docs: Move arc architecture docs under Documentation/arch/
docs: move nios2 documentation under Documentation/arch/
docs: move openrisc documentation under Documentation/arch/
docs: move superh documentation under Documentation/arch/
...
Now we use ARCH_WANT_HUGETLB_PAGE_OPTIMIZE_VMEMMAP config option to
indicate devdax and hugetlb vmemmap optimization support. Hence rename
that to a generic ARCH_WANT_OPTIMIZE_VMEMMAP
Link: https://lkml.kernel.org/r/20230412050025.84346-2-aneesh.kumar@linux.ibm.com
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Reviewed-by: Muchun Song <songmuchun@bytedance.com>
Cc: Joao Martins <joao.m.martins@oracle.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Tarun Sahu <tsahu@linux.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Attempt VMA lock-based page fault handling first, and fall back to the
existing mmap_lock-based handling if that fails.
Link: https://lkml.kernel.org/r/20230227173632.3292573-30-surenb@google.com
Signed-off-by: Suren Baghdasaryan <surenb@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
We introduce a new HAS_IOPORT Kconfig option to indicate support for I/O
Port access. In a future patch HAS_IOPORT=n will disable compilation of
the I/O accessor functions inb()/outb() and friends on architectures
which can not meaningfully support legacy I/O spaces such as s390.
The following architectures do not select HAS_IOPORT:
* ARC
* C-SKY
* Hexagon
* Nios II
* OpenRISC
* s390
* User-Mode Linux
* Xtensa
All other architectures select HAS_IOPORT at least conditionally.
The "depends on" relations on HAS_IOPORT in drivers as well as ifdefs
for HAS_IOPORT specific sections will be added in subsequent patches on
a per subsystem basis.
Co-developed-by: Arnd Bergmann <arnd@kernel.org>
Signed-off-by: Arnd Bergmann <arnd@kernel.org>
Acked-by: Johannes Berg <johannes@sipsolutions.net> # for ARCH=um
Acked-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Niklas Schnelle <schnelle@linux.ibm.com>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Now that the SRCU Kconfig option is unconditionally selected, there is
no longer any point in selecting it. Therefore, remove the "select SRCU"
Kconfig statements.
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: <x86@kernel.org>
Reviewed-by: John Ogness <john.ogness@linutronix.de>
Signed-off-by: Joel Fernandes (Google) <joel@joelfernandes.org>
Move the x86 documentation under Documentation/arch/ as a way of cleaning
up the top-level directory and making the structure of our docs more
closely match the structure of the source directories it describes.
All in-kernel references to the old paths have been updated.
Acked-by: Dave Hansen <dave.hansen@linux.intel.com>
Cc: linux-arch@vger.kernel.org
Cc: x86@kernel.org
Cc: Borislav Petkov <bp@alien8.de>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/lkml/20230315211523.108836-1-corbet@lwn.net/
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Enumerate Linear Address Masking and provide defines for CR3 and CR4
flags.
The new CONFIG_ADDRESS_MASKING option enables the feature support in
kernel.
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Reviewed-by: Alexander Potapenko <glider@google.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Tested-by: Alexander Potapenko <glider@google.com>
Link: https://lore.kernel.org/all/20230312112612.31869-4-kirill.shutemov%40linux.intel.com
- Add powerpc qspinlock implementation optimised for large system scalability and
paravirt. See the merge message for more details.
- Enable objtool to be built on powerpc to generate mcount locations.
- Use a temporary mm for code patching with the Radix MMU, so the writable mapping is
restricted to the patching CPU.
- Add an option to build the 64-bit big-endian kernel with the ELFv2 ABI.
- Sanitise user registers on interrupt entry on 64-bit Book3S.
- Many other small features and fixes.
Thanks to: Aboorva Devarajan, Angel Iglesias, Benjamin Gray, Bjorn Helgaas, Bo Liu, Chen
Lifu, Christoph Hellwig, Christophe JAILLET, Christophe Leroy, Christopher M. Riedl, Colin
Ian King, Deming Wang, Disha Goel, Dmitry Torokhov, Finn Thain, Geert Uytterhoeven,
Gustavo A. R. Silva, Haowen Bai, Joel Stanley, Jordan Niethe, Julia Lawall, Kajol Jain,
Laurent Dufour, Li zeming, Miaoqian Lin, Michael Jeanson, Nathan Lynch, Naveen N. Rao,
Nayna Jain, Nicholas Miehlbradt, Nicholas Piggin, Pali Rohár, Randy Dunlap, Rohan McLure,
Russell Currey, Sathvika Vasireddy, Shaomin Deng, Stephen Kitt, Stephen Rothwell, Thomas
Weißschuh, Tiezhu Yang, Uwe Kleine-König, Xie Shaowen, Xiu Jianfeng, XueBing Chen, Yang
Yingliang, Zhang Jiaming, ruanjinjie, Jessica Yu, Wolfram Sang.
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Merge tag 'powerpc-6.2-1' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux
Pull powerpc updates from Michael Ellerman:
- Add powerpc qspinlock implementation optimised for large system
scalability and paravirt. See the merge message for more details
- Enable objtool to be built on powerpc to generate mcount locations
- Use a temporary mm for code patching with the Radix MMU, so the
writable mapping is restricted to the patching CPU
- Add an option to build the 64-bit big-endian kernel with the ELFv2
ABI
- Sanitise user registers on interrupt entry on 64-bit Book3S
- Many other small features and fixes
Thanks to Aboorva Devarajan, Angel Iglesias, Benjamin Gray, Bjorn
Helgaas, Bo Liu, Chen Lifu, Christoph Hellwig, Christophe JAILLET,
Christophe Leroy, Christopher M. Riedl, Colin Ian King, Deming Wang,
Disha Goel, Dmitry Torokhov, Finn Thain, Geert Uytterhoeven, Gustavo A.
R. Silva, Haowen Bai, Joel Stanley, Jordan Niethe, Julia Lawall, Kajol
Jain, Laurent Dufour, Li zeming, Miaoqian Lin, Michael Jeanson, Nathan
Lynch, Naveen N. Rao, Nayna Jain, Nicholas Miehlbradt, Nicholas Piggin,
Pali Rohár, Randy Dunlap, Rohan McLure, Russell Currey, Sathvika
Vasireddy, Shaomin Deng, Stephen Kitt, Stephen Rothwell, Thomas
Weißschuh, Tiezhu Yang, Uwe Kleine-König, Xie Shaowen, Xiu Jianfeng,
XueBing Chen, Yang Yingliang, Zhang Jiaming, ruanjinjie, Jessica Yu,
and Wolfram Sang.
* tag 'powerpc-6.2-1' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux: (181 commits)
powerpc/code-patching: Fix oops with DEBUG_VM enabled
powerpc/qspinlock: Fix 32-bit build
powerpc/prom: Fix 32-bit build
powerpc/rtas: mandate RTAS syscall filtering
powerpc/rtas: define pr_fmt and convert printk call sites
powerpc/rtas: clean up includes
powerpc/rtas: clean up rtas_error_log_max initialization
powerpc/pseries/eeh: use correct API for error log size
powerpc/rtas: avoid scheduling in rtas_os_term()
powerpc/rtas: avoid device tree lookups in rtas_os_term()
powerpc/rtasd: use correct OF API for event scan rate
powerpc/rtas: document rtas_call()
powerpc/pseries: unregister VPA when hot unplugging a CPU
powerpc/pseries: reset the RCU watchdogs after a LPM
powerpc: Take in account addition CPU node when building kexec FDT
powerpc: export the CPU node count
powerpc/cpuidle: Set CPUIDLE_FLAG_POLLING for snooze state
powerpc/dts/fsl: Fix pca954x i2c-mux node names
cxl: Remove unnecessary cxl_pci_window_alignment()
selftests/powerpc: Fix resource leaks
...
* Randomize the per-cpu entry areas
Cleanups:
* Have CR3_ADDR_MASK use PHYSICAL_PAGE_MASK instead of open
coding it
* Move to "native" set_memory_rox() helper
* Clean up pmd_get_atomic() and i386-PAE
* Remove some unused page table size macros
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Merge tag 'x86_mm_for_6.2_v2' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 mm updates from Dave Hansen:
"New Feature:
- Randomize the per-cpu entry areas
Cleanups:
- Have CR3_ADDR_MASK use PHYSICAL_PAGE_MASK instead of open coding it
- Move to "native" set_memory_rox() helper
- Clean up pmd_get_atomic() and i386-PAE
- Remove some unused page table size macros"
* tag 'x86_mm_for_6.2_v2' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (35 commits)
x86/mm: Ensure forced page table splitting
x86/kasan: Populate shadow for shared chunk of the CPU entry area
x86/kasan: Add helpers to align shadow addresses up and down
x86/kasan: Rename local CPU_ENTRY_AREA variables to shorten names
x86/mm: Populate KASAN shadow for entire per-CPU range of CPU entry area
x86/mm: Recompute physical address for every page of per-CPU CEA mapping
x86/mm: Rename __change_page_attr_set_clr(.checkalias)
x86/mm: Inhibit _PAGE_NX changes from cpa_process_alias()
x86/mm: Untangle __change_page_attr_set_clr(.checkalias)
x86/mm: Add a few comments
x86/mm: Fix CR3_ADDR_MASK
x86/mm: Remove P*D_PAGE_MASK and P*D_PAGE_SIZE macros
mm: Convert __HAVE_ARCH_P..P_GET to the new style
mm: Remove pointless barrier() after pmdp_get_lockless()
x86/mm/pae: Get rid of set_64bit()
x86_64: Remove pointless set_64bit() usage
x86/mm/pae: Be consistent with pXXp_get_and_clear()
x86/mm/pae: Use WRITE_ONCE()
x86/mm/pae: Don't (ab)use atomic64
mm/gup: Fix the lockless PMD access
...
GPIO core:
- teach gpiolib to work with software nodes for HW description
- remove ARCH_NR_GPIOS treewide as we no longer impose any limit on the number
of GPIOS since the allocation became entirely dynamic
- add support for HW quirks for Cirrus CS42L56 codec, Marvell NFC controller,
Freescale PCIe and Ethernet controller, Himax LCDs and Mediatek mt2701
- refactor OF quirk code
- some general refactoring of the OF and ACPI code, adding new helpers, minor
tweaks and fixes, making fwnode usage consistent etc.
GPIO uAPI:
- fix an issue where the user-space can trigger a NULL-pointer dereference in
the kernel by opening a device file, forcing a driver unbind and then calling
one of the syscalls on the associated file descriptor
New drivers:
- add gpio-latch: a new GPIO multiplexer based on latches connected to other
GPIOs
Driver updates:
- convert i2c GPIO expanders to using .probe_new()
- drop the gpio-sta2x11 driver
- factor out common code for the ACCES IDIO-16 family of controllers and use
this new library wherever applicable in drivers
- add DT support to gpio-hisi
- allow building gpio-davinci as a module and increase its maxItems property
- add support for a new model to gpio-pca9570
- other minor changes to various drivers
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Merge tag 'gpio-updates-for-v6.2' of git://git.kernel.org/pub/scm/linux/kernel/git/brgl/linux
Pull gpio updates from Bartosz Golaszewski:
"We have a new GPIO multiplexer driver, bunch of driver updates and
refactoring in the core GPIO library.
GPIO core:
- teach gpiolib to work with software nodes for HW description
- remove ARCH_NR_GPIOS treewide as we no longer impose any limit on
the number of GPIOS since the allocation became entirely dynamic
- add support for HW quirks for Cirrus CS42L56 codec, Marvell NFC
controller, Freescale PCIe and Ethernet controller, Himax LCDs and
Mediatek mt2701
- refactor OF quirk code
- some general refactoring of the OF and ACPI code, adding new
helpers, minor tweaks and fixes, making fwnode usage consistent
etc.
GPIO uAPI:
- fix an issue where the user-space can trigger a NULL-pointer
dereference in the kernel by opening a device file, forcing a
driver unbind and then calling one of the syscalls on the
associated file descriptor
New drivers:
- add gpio-latch: a new GPIO multiplexer based on latches connected
to other GPIOs
Driver updates:
- convert i2c GPIO expanders to using .probe_new()
- drop the gpio-sta2x11 driver
- factor out common code for the ACCES IDIO-16 family of controllers
and use this new library wherever applicable in drivers
- add DT support to gpio-hisi
- allow building gpio-davinci as a module and increase its maxItems
property
- add support for a new model to gpio-pca9570
- other minor changes to various drivers"
* tag 'gpio-updates-for-v6.2' of git://git.kernel.org/pub/scm/linux/kernel/git/brgl/linux: (66 commits)
gpio: sim: set a limit on the number of GPIOs
gpiolib: protect the GPIO device against being dropped while in use by user-space
gpiolib: cdev: fix NULL-pointer dereferences
gpiolib: Provide to_gpio_device() helper
gpiolib: Unify access to the device properties
gpio: Do not include <linux/kernel.h> when not really needed.
gpio: pcf857x: Convert to i2c's .probe_new()
gpio: pca953x: Convert to i2c's .probe_new()
gpio: max732x: Convert to i2c's .probe_new()
dt-bindings: gpio: gpio-davinci: Increase maxItems in gpio-line-names
gpiolib: ensure that fwnode is properly set
gpio: sl28cpld: Replace irqchip mask_invert with unmask_base
gpiolib: of: Use correct fwnode for DT-probed chips
gpiolib: of: Drop redundant check in of_mm_gpiochip_remove()
gpiolib: of: Prepare of_mm_gpiochip_add_data() for fwnode
gpiolib: add support for software nodes
gpiolib: consolidate GPIO lookups
gpiolib: acpi: avoid leaking ACPI details into upper gpiolib layers
gpiolib: acpi: teach acpi_find_gpio() to handle data-only nodes
gpiolib: acpi: change acpi_find_gpio() to accept firmware node
...
been long in the making. It is a lighterweight software-only fix for
Skylake-based cores where enabling IBRS is a big hammer and causes a
significant performance impact.
What it basically does is, it aligns all kernel functions to 16 bytes
boundary and adds a 16-byte padding before the function, objtool
collects all functions' locations and when the mitigation gets applied,
it patches a call accounting thunk which is used to track the call depth
of the stack at any time.
When that call depth reaches a magical, microarchitecture-specific value
for the Return Stack Buffer, the code stuffs that RSB and avoids its
underflow which could otherwise lead to the Intel variant of Retbleed.
This software-only solution brings a lot of the lost performance back,
as benchmarks suggest:
https://lore.kernel.org/all/20220915111039.092790446@infradead.org/
That page above also contains a lot more detailed explanation of the
whole mechanism
- Implement a new control flow integrity scheme called FineIBT which is
based on the software kCFI implementation and uses hardware IBT support
where present to annotate and track indirect branches using a hash to
validate them
- Other misc fixes and cleanups
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Merge tag 'x86_core_for_v6.2' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 core updates from Borislav Petkov:
- Add the call depth tracking mitigation for Retbleed which has been
long in the making. It is a lighterweight software-only fix for
Skylake-based cores where enabling IBRS is a big hammer and causes a
significant performance impact.
What it basically does is, it aligns all kernel functions to 16 bytes
boundary and adds a 16-byte padding before the function, objtool
collects all functions' locations and when the mitigation gets
applied, it patches a call accounting thunk which is used to track
the call depth of the stack at any time.
When that call depth reaches a magical, microarchitecture-specific
value for the Return Stack Buffer, the code stuffs that RSB and
avoids its underflow which could otherwise lead to the Intel variant
of Retbleed.
This software-only solution brings a lot of the lost performance
back, as benchmarks suggest:
https://lore.kernel.org/all/20220915111039.092790446@infradead.org/
That page above also contains a lot more detailed explanation of the
whole mechanism
- Implement a new control flow integrity scheme called FineIBT which is
based on the software kCFI implementation and uses hardware IBT
support where present to annotate and track indirect branches using a
hash to validate them
- Other misc fixes and cleanups
* tag 'x86_core_for_v6.2' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (80 commits)
x86/paravirt: Use common macro for creating simple asm paravirt functions
x86/paravirt: Remove clobber bitmask from .parainstructions
x86/debug: Include percpu.h in debugreg.h to get DECLARE_PER_CPU() et al
x86/cpufeatures: Move X86_FEATURE_CALL_DEPTH from bit 18 to bit 19 of word 11, to leave space for WIP X86_FEATURE_SGX_EDECCSSA bit
x86/Kconfig: Enable kernel IBT by default
x86,pm: Force out-of-line memcpy()
objtool: Fix weak hole vs prefix symbol
objtool: Optimize elf_dirty_reloc_sym()
x86/cfi: Add boot time hash randomization
x86/cfi: Boot time selection of CFI scheme
x86/ibt: Implement FineIBT
objtool: Add --cfi to generate the .cfi_sites section
x86: Add prefix symbols for function padding
objtool: Add option to generate prefix symbols
objtool: Avoid O(bloody terrible) behaviour -- an ode to libelf
objtool: Slice up elf_create_section_symbol()
kallsyms: Revert "Take callthunks into account"
x86: Unconfuse CONFIG_ and X86_FEATURE_ namespaces
x86/retpoline: Fix crash printing warning
x86/paravirt: Fix a !PARAVIRT build warning
...
EFI mixed-mode code to a separate compilation unit, the AMD memory
encryption early code where it belongs and fixing up build dependencies.
Make the deprecated EFI handover protocol optional with the goal of
removing it at some point (Ard Biesheuvel)
- Skip realmode init code on Xen PV guests as it is not needed there
- Remove an old 32-bit PIC code compiler workaround
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Merge tag 'x86_boot_for_v6.2' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 boot updates from Borislav Petkov:
"A of early boot cleanups and fixes.
- Do some spring cleaning to the compressed boot code by moving the
EFI mixed-mode code to a separate compilation unit, the AMD memory
encryption early code where it belongs and fixing up build
dependencies. Make the deprecated EFI handover protocol optional
with the goal of removing it at some point (Ard Biesheuvel)
- Skip realmode init code on Xen PV guests as it is not needed there
- Remove an old 32-bit PIC code compiler workaround"
* tag 'x86_boot_for_v6.2' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/boot: Remove x86_32 PIC using %ebx workaround
x86/boot: Skip realmode init code when running as Xen PV guest
x86/efi: Make the deprecated EFI handover protocol optional
x86/boot/compressed: Only build mem_encrypt.S if AMD_MEM_ENCRYPT=y
x86/boot/compressed: Adhere to calling convention in get_sev_encryption_bit()
x86/boot/compressed: Move startup32_check_sev_cbit() out of head_64.S
x86/boot/compressed: Move startup32_check_sev_cbit() into .text
x86/boot/compressed: Move startup32_load_idt() out of head_64.S
x86/boot/compressed: Move startup32_load_idt() into .text section
x86/boot/compressed: Pull global variable reference into startup32_load_idt()
x86/boot/compressed: Avoid touching ECX in startup32_set_idt_entry()
x86/boot/compressed: Simplify IDT/GDT preserve/restore in the EFI thunk
x86/boot/compressed, efi: Merge multiple definitions of image_offset into one
x86/boot/compressed: Move efi32_pe_entry() out of head_64.S
x86/boot/compressed: Move efi32_entry out of head_64.S
x86/boot/compressed: Move efi32_pe_entry into .text section
x86/boot/compressed: Move bootargs parsing out of 32-bit startup code
x86/boot/compressed: Move 32-bit entrypoint code into .text section
x86/boot/compressed: Rename efi_thunk_64.S to efi-mixed.S
- Refactor the zboot code so that it incorporates all the EFI stub
logic, rather than calling the decompressed kernel as a EFI app.
- Add support for initrd= command line option to x86 mixed mode.
- Allow initrd= to be used with arbitrary EFI accessible file systems
instead of just the one the kernel itself was loaded from.
- Move some x86-only handling and manipulation of the EFI memory map
into arch/x86, as it is not used anywhere else.
- More flexible handling of any random seeds provided by the boot
environment (i.e., systemd-boot) so that it becomes available much
earlier during the boot.
- Allow improved arch-agnostic EFI support in loaders, by setting a
uniform baseline of supported features, and adding a generic magic
number to the DOS/PE header. This should allow loaders such as GRUB or
systemd-boot to reduce the amount of arch-specific handling
substantially.
- (arm64) Run EFI runtime services from a dedicated stack, and use it to
recover from synchronous exceptions that might occur in the firmware
code.
- (arm64) Ensure that we don't allocate memory outside of the 48-bit
addressable physical range.
- Make EFI pstore record size configurable
- Add support for decoding CXL specific CPER records
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Merge tag 'efi-next-for-v6.2' of git://git.kernel.org/pub/scm/linux/kernel/git/efi/efi
Pull EFI updates from Ard Biesheuvel:
"Another fairly sizable pull request, by EFI subsystem standards.
Most of the work was done by me, some of it in collaboration with the
distro and bootloader folks (GRUB, systemd-boot), where the main focus
has been on removing pointless per-arch differences in the way EFI
boots a Linux kernel.
- Refactor the zboot code so that it incorporates all the EFI stub
logic, rather than calling the decompressed kernel as a EFI app.
- Add support for initrd= command line option to x86 mixed mode.
- Allow initrd= to be used with arbitrary EFI accessible file systems
instead of just the one the kernel itself was loaded from.
- Move some x86-only handling and manipulation of the EFI memory map
into arch/x86, as it is not used anywhere else.
- More flexible handling of any random seeds provided by the boot
environment (i.e., systemd-boot) so that it becomes available much
earlier during the boot.
- Allow improved arch-agnostic EFI support in loaders, by setting a
uniform baseline of supported features, and adding a generic magic
number to the DOS/PE header. This should allow loaders such as GRUB
or systemd-boot to reduce the amount of arch-specific handling
substantially.
- (arm64) Run EFI runtime services from a dedicated stack, and use it
to recover from synchronous exceptions that might occur in the
firmware code.
- (arm64) Ensure that we don't allocate memory outside of the 48-bit
addressable physical range.
- Make EFI pstore record size configurable
- Add support for decoding CXL specific CPER records"
* tag 'efi-next-for-v6.2' of git://git.kernel.org/pub/scm/linux/kernel/git/efi/efi: (43 commits)
arm64: efi: Recover from synchronous exceptions occurring in firmware
arm64: efi: Execute runtime services from a dedicated stack
arm64: efi: Limit allocations to 48-bit addressable physical region
efi: Put Linux specific magic number in the DOS header
efi: libstub: Always enable initrd command line loader and bump version
efi: stub: use random seed from EFI variable
efi: vars: prohibit reading random seed variables
efi: random: combine bootloader provided RNG seed with RNG protocol output
efi/cper, cxl: Decode CXL Error Log
efi/cper, cxl: Decode CXL Protocol Error Section
efi: libstub: fix efi_load_initrd_dev_path() kernel-doc comment
efi: x86: Move EFI runtime map sysfs code to arch/x86
efi: runtime-maps: Clarify purpose and enable by default for kexec
efi: pstore: Add module parameter for setting the record size
efi: xen: Set EFI_PARAVIRT for Xen dom0 boot on all architectures
efi: memmap: Move manipulation routines into x86 arch tree
efi: memmap: Move EFI fake memmap support into x86 arch tree
efi: libstub: Undeprecate the command line initrd loader
efi: libstub: Add mixed mode support to command line initrd loader
efi: libstub: Permit mixed mode return types other than efi_status_t
...
- Add the cpu_cache_invalidate_memregion() API for cache flushing in
response to physical memory reconfiguration, or memory-side data
invalidation from operations like secure erase or memory-device unlock.
- Add a facility for the kernel to warn about collisions between kernel
and userspace access to PCI configuration registers
- Add support for Restricted CXL Host (RCH) topologies (formerly CXL 1.1)
- Add handling and reporting of CXL errors reported via the PCIe AER
mechanism
- Add support for CXL Persistent Memory Security commands
- Add support for the "XOR" algorithm for CXL host bridge interleave
- Rework / simplify CXL to NVDIMM interactions
- Miscellaneous cleanups and fixes
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Merge tag 'cxl-for-6.2' of git://git.kernel.org/pub/scm/linux/kernel/git/cxl/cxl
Pull cxl updates from Dan Williams:
"Compute Express Link (CXL) updates for 6.2.
While it may seem backwards, the CXL update this time around includes
some focus on CXL 1.x enabling where the work to date had been with
CXL 2.0 (VH topologies) in mind.
First generation CXL can mostly be supported via BIOS, similar to DDR,
however it became clear there are use cases for OS native CXL error
handling and some CXL 3.0 endpoint features can be deployed on CXL 1.x
hosts (Restricted CXL Host (RCH) topologies). So, this update brings
RCH topologies into the Linux CXL device model.
In support of the ongoing CXL 2.0+ enabling two new core kernel
facilities are added.
One is the ability for the kernel to flag collisions between userspace
access to PCI configuration registers and kernel accesses. This is
brought on by the PCIe Data-Object-Exchange (DOE) facility, a hardware
mailbox over config-cycles.
The other is a cpu_cache_invalidate_memregion() API that maps to
wbinvd_on_all_cpus() on x86. To prevent abuse it is disabled in guest
VMs and architectures that do not support it yet. The CXL paths that
need it, dynamic memory region creation and security commands (erase /
unlock), are disabled when it is not present.
As for the CXL 2.0+ this cycle the subsystem gains support Persistent
Memory Security commands, error handling in response to PCIe AER
notifications, and support for the "XOR" host bridge interleave
algorithm.
Summary:
- Add the cpu_cache_invalidate_memregion() API for cache flushing in
response to physical memory reconfiguration, or memory-side data
invalidation from operations like secure erase or memory-device
unlock.
- Add a facility for the kernel to warn about collisions between
kernel and userspace access to PCI configuration registers
- Add support for Restricted CXL Host (RCH) topologies (formerly CXL
1.1)
- Add handling and reporting of CXL errors reported via the PCIe AER
mechanism
- Add support for CXL Persistent Memory Security commands
- Add support for the "XOR" algorithm for CXL host bridge interleave
- Rework / simplify CXL to NVDIMM interactions
- Miscellaneous cleanups and fixes"
* tag 'cxl-for-6.2' of git://git.kernel.org/pub/scm/linux/kernel/git/cxl/cxl: (71 commits)
cxl/region: Fix memdev reuse check
cxl/pci: Remove endian confusion
cxl/pci: Add some type-safety to the AER trace points
cxl/security: Drop security command ioctl uapi
cxl/mbox: Add variable output size validation for internal commands
cxl/mbox: Enable cxl_mbox_send_cmd() users to validate output size
cxl/security: Fix Get Security State output payload endian handling
cxl: update names for interleave ways conversion macros
cxl: update names for interleave granularity conversion macros
cxl/acpi: Warn about an invalid CHBCR in an existing CHBS entry
tools/testing/cxl: Require cache invalidation bypass
cxl/acpi: Fail decoder add if CXIMS for HBIG is missing
cxl/region: Fix spelling mistake "memergion" -> "memregion"
cxl/regs: Fix sparse warning
cxl/acpi: Set ACPI's CXL _OSC to indicate RCD mode support
tools/testing/cxl: Add an RCH topology
cxl/port: Add RCD endpoint port enumeration
cxl/mem: Move devm_cxl_add_endpoint() from cxl_core to cxl_mem
tools/testing/cxl: Add XOR Math support to cxl_test
cxl/acpi: Support CXL XOR Interleave Math (CXIMS)
...
- Handle the case where x2APIC is enabled and locked by the BIOS on a
kernel with CONFIG_X86_X2APIC=n gracefully. Instead of a panic which
does not make it to the graphical console during very early boot,
simply disable the local APIC completely and boot with the PIC and very
limited functionality, which allows to diagnose the issue.
- Convert x86 APIC device tree bindings to YAML
- Extend x86 APIC device tree bindings to configure interrupt delivery
mode and handle this in during init. This allows to boot with device
tree on platforms which lack a legacy PIC.
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Merge tag 'x86-apic-2022-12-10' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 apic update from Thomas Gleixner:
"A set of changes for the x86 APIC code:
- Handle the case where x2APIC is enabled and locked by the BIOS on a
kernel with CONFIG_X86_X2APIC=n gracefully.
Instead of a panic which does not make it to the graphical console
during very early boot, simply disable the local APIC completely
and boot with the PIC and very limited functionality, which allows
to diagnose the issue
- Convert x86 APIC device tree bindings to YAML
- Extend x86 APIC device tree bindings to configure interrupt
delivery mode and handle this in during init. This allows to boot
with device tree on platforms which lack a legacy PIC"
* tag 'x86-apic-2022-12-10' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/of: Add support for boot time interrupt delivery mode configuration
x86/of: Replace printk(KERN_LVL) with pr_lvl()
dt-bindings: x86: apic: Introduce new optional bool property for lapic
dt-bindings: x86: apic: Convert Intel's APIC bindings to YAML schema
x86/of: Remove unused early_init_dt_add_memory_arch()
x86/apic: Handle no CONFIG_X86_X2APIC on systems with x2APIC enabled by BIOS
- Core:
The bulk is the rework of the MSI subsystem to support per device MSI
interrupt domains. This solves conceptual problems of the current
PCI/MSI design which are in the way of providing support for PCI/MSI[-X]
and the upcoming PCI/IMS mechanism on the same device.
IMS (Interrupt Message Store] is a new specification which allows device
manufactures to provide implementation defined storage for MSI messages
contrary to the uniform and specification defined storage mechanisms for
PCI/MSI and PCI/MSI-X. IMS not only allows to overcome the size limitations
of the MSI-X table, but also gives the device manufacturer the freedom to
store the message in arbitrary places, even in host memory which is shared
with the device.
There have been several attempts to glue this into the current MSI code,
but after lengthy discussions it turned out that there is a fundamental
design problem in the current PCI/MSI-X implementation. This needs some
historical background.
When PCI/MSI[-X] support was added around 2003, interrupt management was
completely different from what we have today in the actively developed
architectures. Interrupt management was completely architecture specific
and while there were attempts to create common infrastructure the
commonalities were rudimentary and just providing shared data structures and
interfaces so that drivers could be written in an architecture agnostic
way.
The initial PCI/MSI[-X] support obviously plugged into this model which
resulted in some basic shared infrastructure in the PCI core code for
setting up MSI descriptors, which are a pure software construct for holding
data relevant for a particular MSI interrupt, but the actual association to
Linux interrupts was completely architecture specific. This model is still
supported today to keep museum architectures and notorious stranglers
alive.
In 2013 Intel tried to add support for hot-pluggable IO/APICs to the kernel,
which was creating yet another architecture specific mechanism and resulted
in an unholy mess on top of the existing horrors of x86 interrupt handling.
The x86 interrupt management code was already an incomprehensible maze of
indirections between the CPU vector management, interrupt remapping and the
actual IO/APIC and PCI/MSI[-X] implementation.
At roughly the same time ARM struggled with the ever growing SoC specific
extensions which were glued on top of the architected GIC interrupt
controller.
This resulted in a fundamental redesign of interrupt management and
provided the today prevailing concept of hierarchical interrupt
domains. This allowed to disentangle the interactions between x86 vector
domain and interrupt remapping and also allowed ARM to handle the zoo of
SoC specific interrupt components in a sane way.
The concept of hierarchical interrupt domains aims to encapsulate the
functionality of particular IP blocks which are involved in interrupt
delivery so that they become extensible and pluggable. The X86
encapsulation looks like this:
|--- device 1
[Vector]---[Remapping]---[PCI/MSI]--|...
|--- device N
where the remapping domain is an optional component and in case that it is
not available the PCI/MSI[-X] domains have the vector domain as their
parent. This reduced the required interaction between the domains pretty
much to the initialization phase where it is obviously required to
establish the proper parent relation ship in the components of the
hierarchy.
While in most cases the model is strictly representing the chain of IP
blocks and abstracting them so they can be plugged together to form a
hierarchy, the design stopped short on PCI/MSI[-X]. Looking at the hardware
it's clear that the actual PCI/MSI[-X] interrupt controller is not a global
entity, but strict a per PCI device entity.
Here we took a short cut on the hierarchical model and went for the easy
solution of providing "global" PCI/MSI domains which was possible because
the PCI/MSI[-X] handling is uniform across the devices. This also allowed
to keep the existing PCI/MSI[-X] infrastructure mostly unchanged which in
turn made it simple to keep the existing architecture specific management
alive.
A similar problem was created in the ARM world with support for IP block
specific message storage. Instead of going all the way to stack a IP block
specific domain on top of the generic MSI domain this ended in a construct
which provides a "global" platform MSI domain which allows overriding the
irq_write_msi_msg() callback per allocation.
In course of the lengthy discussions we identified other abuse of the MSI
infrastructure in wireless drivers, NTB etc. where support for
implementation specific message storage was just mindlessly glued into the
existing infrastructure. Some of this just works by chance on particular
platforms but will fail in hard to diagnose ways when the driver is used
on platforms where the underlying MSI interrupt management code does not
expect the creative abuse.
Another shortcoming of today's PCI/MSI-X support is the inability to
allocate or free individual vectors after the initial enablement of
MSI-X. This results in an works by chance implementation of VFIO (PCI
pass-through) where interrupts on the host side are not set up upfront to
avoid resource exhaustion. They are expanded at run-time when the guest
actually tries to use them. The way how this is implemented is that the
host disables MSI-X and then re-enables it with a larger number of
vectors again. That works by chance because most device drivers set up
all interrupts before the device actually will utilize them. But that's
not universally true because some drivers allocate a large enough number
of vectors but do not utilize them until it's actually required,
e.g. for acceleration support. But at that point other interrupts of the
device might be in active use and the MSI-X disable/enable dance can
just result in losing interrupts and therefore hard to diagnose subtle
problems.
Last but not least the "global" PCI/MSI-X domain approach prevents to
utilize PCI/MSI[-X] and PCI/IMS on the same device due to the fact that IMS
is not longer providing a uniform storage and configuration model.
The solution to this is to implement the missing step and switch from
global PCI/MSI domains to per device PCI/MSI domains. The resulting
hierarchy then looks like this:
|--- [PCI/MSI] device 1
[Vector]---[Remapping]---|...
|--- [PCI/MSI] device N
which in turn allows to provide support for multiple domains per device:
|--- [PCI/MSI] device 1
|--- [PCI/IMS] device 1
[Vector]---[Remapping]---|...
|--- [PCI/MSI] device N
|--- [PCI/IMS] device N
This work converts the MSI and PCI/MSI core and the x86 interrupt
domains to the new model, provides new interfaces for post-enable
allocation/free of MSI-X interrupts and the base framework for PCI/IMS.
PCI/IMS has been verified with the work in progress IDXD driver.
There is work in progress to convert ARM over which will replace the
platform MSI train-wreck. The cleanup of VFIO, NTB and other creative
"solutions" are in the works as well.
- Drivers:
- Updates for the LoongArch interrupt chip drivers
- Support for MTK CIRQv2
- The usual small fixes and updates all over the place
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Merge tag 'irq-core-2022-12-10' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull irq updates from Thomas Gleixner:
"Updates for the interrupt core and driver subsystem:
The bulk is the rework of the MSI subsystem to support per device MSI
interrupt domains. This solves conceptual problems of the current
PCI/MSI design which are in the way of providing support for
PCI/MSI[-X] and the upcoming PCI/IMS mechanism on the same device.
IMS (Interrupt Message Store] is a new specification which allows
device manufactures to provide implementation defined storage for MSI
messages (as opposed to PCI/MSI and PCI/MSI-X that has a specified
message store which is uniform accross all devices). The PCI/MSI[-X]
uniformity allowed us to get away with "global" PCI/MSI domains.
IMS not only allows to overcome the size limitations of the MSI-X
table, but also gives the device manufacturer the freedom to store the
message in arbitrary places, even in host memory which is shared with
the device.
There have been several attempts to glue this into the current MSI
code, but after lengthy discussions it turned out that there is a
fundamental design problem in the current PCI/MSI-X implementation.
This needs some historical background.
When PCI/MSI[-X] support was added around 2003, interrupt management
was completely different from what we have today in the actively
developed architectures. Interrupt management was completely
architecture specific and while there were attempts to create common
infrastructure the commonalities were rudimentary and just providing
shared data structures and interfaces so that drivers could be written
in an architecture agnostic way.
The initial PCI/MSI[-X] support obviously plugged into this model
which resulted in some basic shared infrastructure in the PCI core
code for setting up MSI descriptors, which are a pure software
construct for holding data relevant for a particular MSI interrupt,
but the actual association to Linux interrupts was completely
architecture specific. This model is still supported today to keep
museum architectures and notorious stragglers alive.
In 2013 Intel tried to add support for hot-pluggable IO/APICs to the
kernel, which was creating yet another architecture specific mechanism
and resulted in an unholy mess on top of the existing horrors of x86
interrupt handling. The x86 interrupt management code was already an
incomprehensible maze of indirections between the CPU vector
management, interrupt remapping and the actual IO/APIC and PCI/MSI[-X]
implementation.
At roughly the same time ARM struggled with the ever growing SoC
specific extensions which were glued on top of the architected GIC
interrupt controller.
This resulted in a fundamental redesign of interrupt management and
provided the today prevailing concept of hierarchical interrupt
domains. This allowed to disentangle the interactions between x86
vector domain and interrupt remapping and also allowed ARM to handle
the zoo of SoC specific interrupt components in a sane way.
The concept of hierarchical interrupt domains aims to encapsulate the
functionality of particular IP blocks which are involved in interrupt
delivery so that they become extensible and pluggable. The X86
encapsulation looks like this:
|--- device 1
[Vector]---[Remapping]---[PCI/MSI]--|...
|--- device N
where the remapping domain is an optional component and in case that
it is not available the PCI/MSI[-X] domains have the vector domain as
their parent. This reduced the required interaction between the
domains pretty much to the initialization phase where it is obviously
required to establish the proper parent relation ship in the
components of the hierarchy.
While in most cases the model is strictly representing the chain of IP
blocks and abstracting them so they can be plugged together to form a
hierarchy, the design stopped short on PCI/MSI[-X]. Looking at the
hardware it's clear that the actual PCI/MSI[-X] interrupt controller
is not a global entity, but strict a per PCI device entity.
Here we took a short cut on the hierarchical model and went for the
easy solution of providing "global" PCI/MSI domains which was possible
because the PCI/MSI[-X] handling is uniform across the devices. This
also allowed to keep the existing PCI/MSI[-X] infrastructure mostly
unchanged which in turn made it simple to keep the existing
architecture specific management alive.
A similar problem was created in the ARM world with support for IP
block specific message storage. Instead of going all the way to stack
a IP block specific domain on top of the generic MSI domain this ended
in a construct which provides a "global" platform MSI domain which
allows overriding the irq_write_msi_msg() callback per allocation.
In course of the lengthy discussions we identified other abuse of the
MSI infrastructure in wireless drivers, NTB etc. where support for
implementation specific message storage was just mindlessly glued into
the existing infrastructure. Some of this just works by chance on
particular platforms but will fail in hard to diagnose ways when the
driver is used on platforms where the underlying MSI interrupt
management code does not expect the creative abuse.
Another shortcoming of today's PCI/MSI-X support is the inability to
allocate or free individual vectors after the initial enablement of
MSI-X. This results in an works by chance implementation of VFIO (PCI
pass-through) where interrupts on the host side are not set up upfront
to avoid resource exhaustion. They are expanded at run-time when the
guest actually tries to use them. The way how this is implemented is
that the host disables MSI-X and then re-enables it with a larger
number of vectors again. That works by chance because most device
drivers set up all interrupts before the device actually will utilize
them. But that's not universally true because some drivers allocate a
large enough number of vectors but do not utilize them until it's
actually required, e.g. for acceleration support. But at that point
other interrupts of the device might be in active use and the MSI-X
disable/enable dance can just result in losing interrupts and
therefore hard to diagnose subtle problems.
Last but not least the "global" PCI/MSI-X domain approach prevents to
utilize PCI/MSI[-X] and PCI/IMS on the same device due to the fact
that IMS is not longer providing a uniform storage and configuration
model.
The solution to this is to implement the missing step and switch from
global PCI/MSI domains to per device PCI/MSI domains. The resulting
hierarchy then looks like this:
|--- [PCI/MSI] device 1
[Vector]---[Remapping]---|...
|--- [PCI/MSI] device N
which in turn allows to provide support for multiple domains per
device:
|--- [PCI/MSI] device 1
|--- [PCI/IMS] device 1
[Vector]---[Remapping]---|...
|--- [PCI/MSI] device N
|--- [PCI/IMS] device N
This work converts the MSI and PCI/MSI core and the x86 interrupt
domains to the new model, provides new interfaces for post-enable
allocation/free of MSI-X interrupts and the base framework for
PCI/IMS. PCI/IMS has been verified with the work in progress IDXD
driver.
There is work in progress to convert ARM over which will replace the
platform MSI train-wreck. The cleanup of VFIO, NTB and other creative
"solutions" are in the works as well.
Drivers:
- Updates for the LoongArch interrupt chip drivers
- Support for MTK CIRQv2
- The usual small fixes and updates all over the place"
* tag 'irq-core-2022-12-10' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (134 commits)
irqchip/ti-sci-inta: Fix kernel doc
irqchip/gic-v2m: Mark a few functions __init
irqchip/gic-v2m: Include arm-gic-common.h
irqchip/irq-mvebu-icu: Fix works by chance pointer assignment
iommu/amd: Enable PCI/IMS
iommu/vt-d: Enable PCI/IMS
x86/apic/msi: Enable PCI/IMS
PCI/MSI: Provide pci_ims_alloc/free_irq()
PCI/MSI: Provide IMS (Interrupt Message Store) support
genirq/msi: Provide constants for PCI/IMS support
x86/apic/msi: Enable MSI_FLAG_PCI_MSIX_ALLOC_DYN
PCI/MSI: Provide post-enable dynamic allocation interfaces for MSI-X
PCI/MSI: Provide prepare_desc() MSI domain op
PCI/MSI: Split MSI-X descriptor setup
genirq/msi: Provide MSI_FLAG_MSIX_ALLOC_DYN
genirq/msi: Provide msi_domain_alloc_irq_at()
genirq/msi: Provide msi_domain_ops:: Prepare_desc()
genirq/msi: Provide msi_desc:: Msi_data
genirq/msi: Provide struct msi_map
x86/apic/msi: Remove arch_create_remap_msi_irq_domain()
...
This pull request contains the following branches:
doc.2022.10.20a: Documentation updates. This is the second
in a series from an ongoing review of the RCU documentation.
fixes.2022.10.21a: Miscellaneous fixes.
lazy.2022.11.30a: Introduces a default-off Kconfig option that depends
on RCU_NOCB_CPU that, on CPUs mentioned in the nohz_full or
rcu_nocbs boot-argument CPU lists, causes call_rcu() to introduce
delays. These delays result in significant power savings on
nearly idle Android and ChromeOS systems. These savings range
from a few percent to more than ten percent.
This series also includes several commits that change call_rcu()
to a new call_rcu_hurry() function that avoids these delays in
a few cases, for example, where timely wakeups are required.
Several of these are outside of RCU and thus have acks and
reviews from the relevant maintainers.
srcunmisafe.2022.11.09a: Creates an srcu_read_lock_nmisafe() and an
srcu_read_unlock_nmisafe() for architectures that support NMIs,
but which do not provide NMI-safe this_cpu_inc(). These NMI-safe
SRCU functions are required by the upcoming lockless printk()
work by John Ogness et al.
That printk() series depends on these commits, so if you pull
the printk() series before this one, you will have already
pulled in this branch, plus two more SRCU commits:
0cd7e350abc4 ("rcu: Make SRCU mandatory")
51f5f78a4f80 ("srcu: Make Tiny synchronize_srcu() check for readers")
These two commits appear to work well, but do not have
sufficient testing exposure over a long enough time for me to
feel comfortable pushing them unless something in mainline is
definitely going to use them immediately, and currently only
the new printk() work uses them.
torture.2022.10.18c: Changes providing minor but important increases
in test coverage for the new RCU polled-grace-period APIs.
torturescript.2022.10.20a: Changes that avoid redundant kernel builds,
thus providing about a 30% speedup for the torture.sh acceptance
test.
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Merge tag 'rcu.2022.12.02a' of git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu
Pull RCU updates from Paul McKenney:
- Documentation updates. This is the second in a series from an ongoing
review of the RCU documentation.
- Miscellaneous fixes.
- Introduce a default-off Kconfig option that depends on RCU_NOCB_CPU
that, on CPUs mentioned in the nohz_full or rcu_nocbs boot-argument
CPU lists, causes call_rcu() to introduce delays.
These delays result in significant power savings on nearly idle
Android and ChromeOS systems. These savings range from a few percent
to more than ten percent.
This series also includes several commits that change call_rcu() to a
new call_rcu_hurry() function that avoids these delays in a few
cases, for example, where timely wakeups are required. Several of
these are outside of RCU and thus have acks and reviews from the
relevant maintainers.
- Create an srcu_read_lock_nmisafe() and an srcu_read_unlock_nmisafe()
for architectures that support NMIs, but which do not provide
NMI-safe this_cpu_inc(). These NMI-safe SRCU functions are required
by the upcoming lockless printk() work by John Ogness et al.
- Changes providing minor but important increases in torture test
coverage for the new RCU polled-grace-period APIs.
- Changes to torturescript that avoid redundant kernel builds, thus
providing about a 30% speedup for the torture.sh acceptance test.
* tag 'rcu.2022.12.02a' of git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu: (49 commits)
net: devinet: Reduce refcount before grace period
net: Use call_rcu_hurry() for dst_release()
workqueue: Make queue_rcu_work() use call_rcu_hurry()
percpu-refcount: Use call_rcu_hurry() for atomic switch
scsi/scsi_error: Use call_rcu_hurry() instead of call_rcu()
rcu/rcutorture: Use call_rcu_hurry() where needed
rcu/rcuscale: Use call_rcu_hurry() for async reader test
rcu/sync: Use call_rcu_hurry() instead of call_rcu
rcuscale: Add laziness and kfree tests
rcu: Shrinker for lazy rcu
rcu: Refactor code a bit in rcu_nocb_do_flush_bypass()
rcu: Make call_rcu() lazy to save power
rcu: Implement lockdep_rcu_enabled for !CONFIG_DEBUG_LOCK_ALLOC
srcu: Debug NMI safety even on archs that don't require it
srcu: Explain the reason behind the read side critical section on GP start
srcu: Warn when NMI-unsafe API is used in NMI
arch/s390: Add ARCH_HAS_NMI_SAFE_THIS_CPU_OPS Kconfig option
arch/loongarch: Add ARCH_HAS_NMI_SAFE_THIS_CPU_OPS Kconfig option
rcu: Fix __this_cpu_read() lockdep warning in rcu_force_quiescent_state()
rcu-tasks: Make grace-period-age message human-readable
...
A kernel that was compiled without CONFIG_X86_X2APIC was unable to boot on
platforms that have x2APIC already enabled in the BIOS before starting the
kernel.
The kernel was supposed to panic with an approprite error message in
validate_x2apic() due to the missing X2APIC support.
However, validate_x2apic() was run too late in the boot cycle, and the
kernel tried to initialize the APIC nonetheless. This resulted in an
earlier panic in setup_local_APIC() because the APIC was not registered.
In my experiments, a panic message in setup_local_APIC() was not visible
in the graphical console, which resulted in a hang with no indication
what has gone wrong.
Instead of calling panic(), disable the APIC, which results in a somewhat
working system with the PIC only (and no SMP). This way the user is able to
diagnose the problem more easily.
Disabling X2APIC mode is not an option because it's impossible on systems
with locked x2APIC.
The proper place to disable the APIC in this case is in check_x2apic(),
which is called early from setup_arch(). Doing this in
__apic_intr_mode_select() is too late.
Make check_x2apic() unconditionally available and remove the empty stub.
Reported-by: Paul Menzel <pmenzel@molgen.mpg.de>
Reported-by: Robert Elliott (Servers) <elliott@hpe.com>
Signed-off-by: Mateusz Jończyk <mat.jonczyk@o2.pl>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/lkml/d573ba1c-0dc4-3016-712a-cc23a8a33d42@molgen.mpg.de
Link: https://lore.kernel.org/lkml/20220911084711.13694-3-mat.jonczyk@o2.pl
Link: https://lore.kernel.org/all/20221129215008.7247-1-mat.jonczyk@o2.pl
The EFI handover protocol permits a bootloader to invoke the kernel as a
EFI PE/COFF application, while passing a bootparams struct as a third
argument to the entrypoint function call.
This has no basis in the UEFI specification, and there are better ways
to pass additional data to a UEFI application (UEFI configuration
tables, UEFI variables, UEFI protocols) than going around the
StartImage() boot service and jumping to a fixed offset in the loaded
image, just to call a different function that takes a third parameter.
The reason for handling struct bootparams in the bootloader was that the
EFI stub could only load initrd images from the EFI system partition,
and so passing it via struct bootparams was needed for loaders like
GRUB, which pass the initrd in memory, and may load it from anywhere,
including from the network. Another motivation was EFI mixed mode, which
could not use the initrd loader in the EFI stub at all due to 32/64 bit
incompatibilities (which will be fixed shortly [0]), and could not
invoke the ordinary PE/COFF entry point either, for the same reasons.
Given that loaders such as GRUB already carried the bootparams handling
in order to implement non-EFI boot, retaining that code and just passing
bootparams to the EFI stub was a reasonable choice (although defining an
alternate entrypoint could have been avoided.) However, the GRUB side
changes never made it upstream, and are only shipped by some of the
distros in their downstream versions.
In the meantime, EFI support has been added to other Linux architecture
ports, as well as to U-boot and systemd, including arch-agnostic methods
for passing initrd images in memory [1], and for doing mixed mode boot
[2], none of them requiring anything like the EFI handover protocol. So
given that only out-of-tree distro GRUB relies on this, let's permit it
to be omitted from the build, in preparation for retiring it completely
at a later date. (Note that systemd-boot does have an implementation as
well, but only uses it as a fallback for booting images that do not
implement the LoadFile2 based initrd loading method, i.e., v5.8 or older)
[0] https://lore.kernel.org/all/20220927085842.2860715-1-ardb@kernel.org/
[1] ec93fc371f01 ("efi/libstub: Add support for loading the initrd from a device path")
[2] 97aa276579b2 ("efi/x86: Add true mixed mode entry point into .compat section")
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lore.kernel.org/r/20221122161017.2426828-18-ardb@kernel.org
The EFI runtime map code is only wired up on x86, which is the only
architecture that has a need for it in its implementation of kexec.
So let's move this code under arch/x86 and drop all references to it
from generic code. To ensure that the efi_runtime_map_init() is invoked
at the appropriate time use a 'sync' subsys_initcall() that will be
called right after the EFI initcall made from generic code where the
original invocation of efi_runtime_map_init() resided.
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Reviewed-by: Dave Young <dyoung@redhat.com>
The EFI fake memmap support is specific to x86, which manipulates the
EFI memory map in various different ways after receiving it from the EFI
stub. On other architectures, we have managed to push back on this, and
the EFI memory map is kept pristine.
So let's move the fake memmap code into the x86 arch tree, where it
arguably belongs.
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Some architectures (powerpc) may not support ftrace locations being nop'ed
out at build time. Introduce CONFIG_HAVE_OBJTOOL_NOP_MCOUNT for objtool, as
a means for architectures to enable nop'ing of ftrace locations. Add --mnop
as an option to objtool --mcount, to indicate support for the same.
Also, make sure that --mnop can be passed as an option to objtool only when
--mcount is passed.
Tested-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Reviewed-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Acked-by: Josh Poimboeuf <jpoimboe@kernel.org>
Reviewed-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Sathvika Vasireddy <sv@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20221114175754.1131267-12-sv@linux.ibm.com
What a zoo:
PCI_MSI
select GENERIC_MSI_IRQ
PCI_MSI_IRQ_DOMAIN
def_bool y
depends on PCI_MSI
select GENERIC_MSI_IRQ_DOMAIN
Ergo PCI_MSI enables PCI_MSI_IRQ_DOMAIN which in turn selects
GENERIC_MSI_IRQ_DOMAIN. So all the dependencies on PCI_MSI_IRQ_DOMAIN are
just an indirection to PCI_MSI.
Match the reality and just admit that PCI_MSI requires
GENERIC_MSI_IRQ_DOMAIN.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Acked-by: Bjorn Helgaas <bhelgaas@google.com>
Link: https://lore.kernel.org/r/20221111122014.467556921@linutronix.de
With CXL security features, and CXL dynamic provisioning, global CPU
cache flushing nvdimm requirements are no longer specific to that
subsystem, even beyond the scope of security_ops. CXL will need such
semantics for features not necessarily limited to persistent memory.
The functionality this is enabling is to be able to instantaneously
secure erase potentially terabytes of memory at once and the kernel
needs to be sure that none of the data from before the erase is still
present in the cache. It is also used when unlocking a memory device
where speculative reads and firmware accesses could have cached poison
from before the device was unlocked. Lastly this facility is used when
mapping new devices, or new capacity into an established physical
address range. I.e. when the driver switches DeviceA mapping AddressX to
DeviceB mapping AddressX then any cached data from DeviceA:AddressX
needs to be invalidated.
This capability is typically only used once per-boot (for unlock), or
once per bare metal provisioning event (secure erase), like when handing
off the system to another tenant or decommissioning a device. It may
also be used for dynamic CXL region provisioning.
Users must first call cpu_cache_has_invalidate_memregion() to know
whether this functionality is available on the architecture. On x86 this
respects the constraints of when wbinvd() is tolerable. It is already
the case that wbinvd() is problematic to allow in VMs due its global
performance impact and KVM, for example, has been known to just trap and
ignore the call. With confidential computing guest execution of wbinvd()
may even trigger an exception. Given guests should not be messing with
the bare metal address map via CXL configuration changes
cpu_cache_has_invalidate_memregion() returns false in VMs.
While this global cache invalidation facility, is exported to modules,
since NVDIMM and CXL support can be built as a module, it is not for
general use. The intent is that this facility is not available outside
of specific "device-memory" use cases. To make that expectation as clear
as possible the API is scoped to a new "DEVMEM" module namespace that
only the NVDIMM and CXL subsystems are expected to import.
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: x86@kernel.org
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Tested-by: Dave Jiang <dave.jiang@intel.com>
Signed-off-by: Davidlohr Bueso <dave@stgolabs.net>
Acked-by: Dave Hansen <dave.hansen@linux.intel.com>
Co-developed-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
The kernel IBT defense strongly mitigates the common "first step" of ROP
attacks, by eliminating arbitrary stack pivots (that appear either at
the end of a function or in immediate values), which cannot be reached
if indirect calls must be to marked function entry addresses. IBT is
also required to be enabled to gain the FineIBT feature when built with
Kernel Control Flow Integrity.
Additionally, given that this feature is runtime enabled via CPU ID,
it clearly should be built in by default; it will only be enabled if the
CPU supports it. The build takes 2 seconds longer, which seems a small
price to pay for gaining this coverage by default.
Suggested-by: Sami Tolvanen <samitolvanen@google.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20221101172503.gonna.094-kees@kernel.org
Implement an alternative CFI scheme that merges both the fine-grained
nature of kCFI but also takes full advantage of the coarse grained
hardware CFI as provided by IBT.
To contrast:
kCFI is a pure software CFI scheme and relies on being able to read
text -- specifically the instruction *before* the target symbol, and
does the hash validation *before* doing the call (otherwise control
flow is compromised already).
FineIBT is a software and hardware hybrid scheme; by ensuring every
branch target starts with a hash validation it is possible to place
the hash validation after the branch. This has several advantages:
o the (hash) load is avoided; no memop; no RX requirement.
o IBT WAIT-FOR-ENDBR state is a speculation stop; by placing
the hash validation in the immediate instruction after
the branch target there is a minimal speculation window
and the whole is a viable defence against SpectreBHB.
o Kees feels obliged to mention it is slightly more vulnerable
when the attacker can write code.
Obviously this patch relies on kCFI, but additionally it also relies
on the padding from the call-depth-tracking patches. It uses this
padding to place the hash-validation while the call-sites are
re-written to modify the indirect target to be 16 bytes in front of
the original target, thus hitting this new preamble.
Notably, there is no hardware that needs call-depth-tracking (Skylake)
and supports IBT (Tigerlake and onwards).
Suggested-by: Joao Moreira (Intel) <joao@overdrivepizza.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/20221027092842.634714496@infradead.org
When code is compiled with:
-fpatchable-function-entry=${PADDING_BYTES},${PADDING_BYTES}
functions will have PADDING_BYTES of NOP in front of them. Unwinders
and other things that symbolize code locations will typically
attribute these bytes to the preceding function.
Given that these bytes nominally belong to the following symbol this
mis-attribution is confusing.
Inspired by the fact that CFI_CLANG emits __cfi_##name symbols to
claim these bytes, use objtool to emit __pfx_##name symbols to do
the same when CFI_CLANG is not used.
This then shows the callthunk for symbol 'name' as:
__pfx_##name+0x6/0x10
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Tested-by: Yujie Liu <yujie.liu@intel.com>
Link: https://lkml.kernel.org/r/20221028194453.592512209@infradead.org
There's a conflict between the call-depth tracking commits in x86/core:
ee3e2469b346 ("x86/ftrace: Make it call depth tracking aware")
36b64f101219 ("x86/ftrace: Rebalance RSB")
eac828eaef29 ("x86/ftrace: Remove ftrace_epilogue()")
And these fixes in x86/urgent:
883bbbffa5a4 ("ftrace,kcfi: Separate ftrace_stub() and ftrace_stub_graph()")
b5f1fc318440 ("x86/ftrace: Remove ftrace_epilogue()")
It's non-trivial overlapping modifications - resolve them.
Conflicts:
arch/x86/kernel/ftrace_64.S
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Eric DeVolder
Linus Torvalds
Donglin Peng
Thomas Gleixner
Tom Lendacky
Kirill A. Shutemov
Lukas Bulwahn
Aneesh Kumar K.V
Suren Baghdasaryan
Niklas Schnelle
Paul E. McKenney
Jonathan Corbet
Randy Dunlap
Peter Zijlstra
Mateusz Jończyk
Ard Biesheuvel
Sathvika Vasireddy
Davidlohr Bueso
Kees Cook
Ingo Molnar