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[ Upstream commit a2c0b0fbe01419f8f5d1c0b9c581631f34ffce8b ]
The alternatives code must be `noinstr` such that it does not patch itself,
as the cache invalidation is only performed after all the alternatives have
been applied.
Mark patch_alternative() as `noinstr`. Mark branch_insn_requires_update()
and get_alt_insn() with `__always_inline` since they are both only called
through patch_alternative().
Booting a kernel in QEMU TCG with KCSAN=y and ARM64_USE_LSE_ATOMICS=y caused
a boot hang:
[ 0.241121] CPU: All CPU(s) started at EL2
The alternatives code was patching the atomics in __tsan_read4() from LL/SC
atomics to LSE atomics.
The following fragment is using LL/SC atomics in the .text section:
| <__tsan_unaligned_read4+304>: ldxr x6, [x2]
| <__tsan_unaligned_read4+308>: add x6, x6, x5
| <__tsan_unaligned_read4+312>: stxr w7, x6, [x2]
| <__tsan_unaligned_read4+316>: cbnz w7, <__tsan_unaligned_read4+304>
This LL/SC atomic sequence was to be replaced with LSE atomics. However since
the alternatives code was instrumentable, __tsan_read4() was being called after
only the first instruction was replaced, which led to the following code in memory:
| <__tsan_unaligned_read4+304>: ldadd x5, x6, [x2]
| <__tsan_unaligned_read4+308>: add x6, x6, x5
| <__tsan_unaligned_read4+312>: stxr w7, x6, [x2]
| <__tsan_unaligned_read4+316>: cbnz w7, <__tsan_unaligned_read4+304>
This caused an infinite loop as the `stxr` instruction never completed successfully,
so `w7` was always 0.
Signed-off-by: Joey Gouly <joey.gouly@arm.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will@kernel.org>
Link: https://lore.kernel.org/r/20220405104733.11476-1-joey.gouly@arm.com
Signed-off-by: Will Deacon <will@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
commit 01f6c7338ce267959975da65d86ba34f44d54220 upstream.
Currently the first thing checked is whether the PCSI cpu_suspend function
has been initialized.
Another change will be overloading `acpi_processor_ffh_lpi_probe` and
calling it sooner. So make the `has_lpi` check the first thing checked
to prepare for that change.
Reviewed-by: Sudeep Holla <sudeep.holla@arm.com>
Signed-off-by: Mario Limonciello <mario.limonciello@amd.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 4013e26670c590944abdab56c4fa797527b74325 upstream.
On ELF, (NOLOAD) sets the section type to SHT_NOBITS[1]. It is conceptually
inappropriate for .plt and .text.* sections which are always
SHT_PROGBITS.
In GNU ld, if PLT entries are needed, .plt will be SHT_PROGBITS anyway
and (NOLOAD) will be essentially ignored. In ld.lld, since
https://reviews.llvm.org/D118840 ("[ELF] Support (TYPE=<value>) to
customize the output section type"), ld.lld will report a `section type
mismatch` error. Just remove (NOLOAD) to fix the error.
[1] https://lld.llvm.org/ELF/linker_script.html As of today, "The
section should be marked as not loadable" on
https://sourceware.org/binutils/docs/ld/Output-Section-Type.html is
outdated for ELF.
Tested-by: Nathan Chancellor <nathan@kernel.org>
Reported-by: Nathan Chancellor <nathan@kernel.org>
Signed-off-by: Fangrui Song <maskray@google.com>
Acked-by: Ard Biesheuvel <ardb@kernel.org>
Link: https://lore.kernel.org/r/20220218081209.354383-1-maskray@google.com
Signed-off-by: Will Deacon <will@kernel.org>
[nathan: Fix conflicts due to lack of 596b0474d3d9]
Signed-off-by: Nathan Chancellor <nathan@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 31a099dbd91e69fcab55eef4be15ed7a8c984918 upstream.
These patch_text implementations are using stop_machine_cpuslocked
infrastructure with atomic cpu_count. The original idea: When the
master CPU patch_text, the others should wait for it. But current
implementation is using the first CPU as master, which couldn't
guarantee the remaining CPUs are waiting. This patch changes the
last CPU as the master to solve the potential risk.
Fixes: ae16480785de ("arm64: introduce interfaces to hotpatch kernel and module code")
Signed-off-by: Guo Ren <guoren@linux.alibaba.com>
Signed-off-by: Guo Ren <guoren@kernel.org>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Reviewed-by: Masami Hiramatsu <mhiramat@kernel.org>
Cc: <stable@vger.kernel.org>
Link: https://lore.kernel.org/r/20220407073323.743224-2-guoren@kernel.org
Signed-off-by: Will Deacon <will@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
__sdei_asm_trampoline_next_handler shouldn't have its own name as the
tramp_data_read_var takes the symbol name, and generates the name for
the value in the data page if CONFIG_RANDOMIZE_BASE is clear.
This means when CONFIG_RANDOMIZE_BASE is clear, this code won't compile
as __sdei_asm_trampoline_next_handler doesn't exist.
Use the proper name, and let the macro do its thing.
Reported-by: Florian Fainelli <f.fainelli@gmail.com>
Tested-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: James Morse <james.morse@arm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 228a26b912287934789023b4132ba76065d9491c upstream.
Future CPUs may implement a clearbhb instruction that is sufficient
to mitigate SpectreBHB. CPUs that implement this instruction, but
not CSV2.3 must be affected by Spectre-BHB.
Add support to use this instruction as the BHB mitigation on CPUs
that support it. The instruction is in the hint space, so it will
be treated by a NOP as older CPUs.
Reviewed-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
[ modified for stable: Use a KVM vector template instead of alternatives,
removed bitmap of mitigations ]
Signed-off-by: James Morse <james.morse@arm.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
commit 558c303c9734af5a813739cd284879227f7297d2 upstream.
Speculation attacks against some high-performance processors can
make use of branch history to influence future speculation.
When taking an exception from user-space, a sequence of branches
or a firmware call overwrites or invalidates the branch history.
The sequence of branches is added to the vectors, and should appear
before the first indirect branch. For systems using KPTI the sequence
is added to the kpti trampoline where it has a free register as the exit
from the trampoline is via a 'ret'. For systems not using KPTI, the same
register tricks are used to free up a register in the vectors.
For the firmware call, arch-workaround-3 clobbers 4 registers, so
there is no choice but to save them to the EL1 stack. This only happens
for entry from EL0, so if we take an exception due to the stack access,
it will not become re-entrant.
For KVM, the existing branch-predictor-hardening vectors are used.
When a spectre version of these vectors is in use, the firmware call
is sufficient to mitigate against Spectre-BHB. For the non-spectre
versions, the sequence of branches is added to the indirect vector.
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Cc: <stable@kernel.org> # <v5.17.x 72bb9dcb6c33c arm64: Add Cortex-X2 CPU part definition
Cc: <stable@kernel.org> # <v5.16.x 2d0d656700d67 arm64: Add Neoverse-N2, Cortex-A710 CPU part definition
Cc: <stable@kernel.org> # <v5.10.x 8a6b88e66233f arm64: Add part number for Arm Cortex-A77
[ modified for stable, moved code to cpu_errata.c removed bitmap of
mitigations, use kvm template infrastructure ]
Signed-off-by: James Morse <james.morse@arm.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
KVM writes the Spectre-v2 mitigation template at the beginning of each
vector when a CPU requires a specific sequence to run.
Because the template is copied, it can not be modified by the alternatives
at runtime.
Add templates for calling ARCH_WORKAROUND_3 and one for each value of K
in the brancy-loop. Instead of adding dummy functions for 'fn', which would
disable the Spectre-v2 mitigation, add template_start to indicate that a
template (and which one) is in use. Finally add a copy of
install_bp_hardening_cb() that is able to install these.
Signed-off-by: James Morse <james.morse@arm.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
commit dee435be76f4117410bbd90573a881fd33488f37 upstream.
Speculation attacks against some high-performance processors can
make use of branch history to influence future speculation as part of
a spectre-v2 attack. This is not mitigated by CSV2, meaning CPUs that
previously reported 'Not affected' are now moderately mitigated by CSV2.
Update the value in /sys/devices/system/cpu/vulnerabilities/spectre_v2
to also show the state of the BHB mitigation.
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
[ code move to cpu_errata.c for backport ]
Signed-off-by: James Morse <james.morse@arm.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
commit bd09128d16fac3c34b80bd6a29088ac632e8ce09 upstream.
The Spectre-BHB workaround adds a firmware call to the vectors. This
is needed on some CPUs, but not others. To avoid the unaffected CPU in
a big/little pair from making the firmware call, create per cpu vectors.
The per-cpu vectors only apply when returning from EL0.
Systems using KPTI can use the canonical 'full-fat' vectors directly at
EL1, the trampoline exit code will switch to this_cpu_vector on exit to
EL0. Systems not using KPTI should always use this_cpu_vector.
this_cpu_vector will point at a vector in tramp_vecs or
__bp_harden_el1_vectors, depending on whether KPTI is in use.
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: James Morse <james.morse@arm.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
commit b28a8eebe81c186fdb1a0078263b30576c8e1f42 upstream.
The trampoline code needs to use the address of symbols in the wider
kernel, e.g. vectors. PC-relative addressing wouldn't work as the
trampoline code doesn't run at the address the linker expected.
tramp_ventry uses a literal pool, unless CONFIG_RANDOMIZE_BASE is
set, in which case it uses the data page as a literal pool because
the data page can be unmapped when running in user-space, which is
required for CPUs vulnerable to meltdown.
Pull this logic out as a macro, instead of adding a third copy
of it.
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: James Morse <james.morse@arm.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
commit ba2689234be92024e5635d30fe744f4853ad97db upstream.
Some CPUs affected by Spectre-BHB need a sequence of branches, or a
firmware call to be run before any indirect branch. This needs to go
in the vectors. No CPU needs both.
While this can be patched in, it would run on all CPUs as there is a
single set of vectors. If only one part of a big/little combination is
affected, the unaffected CPUs have to run the mitigation too.
Create extra vectors that include the sequence. Subsequent patches will
allow affected CPUs to select this set of vectors. Later patches will
modify the loop count to match what the CPU requires.
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: James Morse <james.morse@arm.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
commit aff65393fa1401e034656e349abd655cfe272de0 upstream.
kpti is an optional feature, for systems not using kpti a set of
vectors for the spectre-bhb mitigations is needed.
Add another set of vectors, __bp_harden_el1_vectors, that will be
used if a mitigation is needed and kpti is not in use.
The EL1 ventries are repeated verbatim as there is no additional
work needed for entry from EL1.
Reviewed-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: James Morse <james.morse@arm.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
commit a9c406e6462ff14956d690de7bbe5131a5677dc9 upstream.
Adding a second set of vectors to .entry.tramp.text will make it
larger than a single 4K page.
Allow the trampoline text to occupy up to three pages by adding two
more fixmap slots. Previous changes to tramp_valias allowed it to reach
beyond a single page.
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: James Morse <james.morse@arm.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
commit c47e4d04ba0f1ea17353d85d45f611277507e07a upstream.
Spectre-BHB needs to add sequences to the vectors. Having one global
set of vectors is a problem for big/little systems where the sequence
is costly on cpus that are not vulnerable.
Making the vectors per-cpu in the style of KVM's bh_harden_hyp_vecs
requires the vectors to be generated by macros.
Make the kpti re-mapping of the kernel optional, so the macros can be
used without kpti.
Reviewed-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: James Morse <james.morse@arm.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
commit 13d7a08352a83ef2252aeb464a5e08dfc06b5dfd upstream.
The macros for building the kpti trampoline are all behind
CONFIG_UNMAP_KERNEL_AT_EL0, and in a region that outputs to the
.entry.tramp.text section.
Move the macros out so they can be used to generate other kinds of
trampoline. Only the symbols need to be guarded by
CONFIG_UNMAP_KERNEL_AT_EL0 and appear in the .entry.tramp.text section.
Reviewed-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: James Morse <james.morse@arm.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
commit ed50da7764535f1e24432ded289974f2bf2b0c5a upstream.
The tramp_ventry macro uses tramp_vectors as the address of the vectors
when calculating which ventry in the 'full fat' vectors to branch to.
While there is one set of tramp_vectors, this will be true.
Adding multiple sets of vectors will break this assumption.
Move the generation of the vectors to a macro, and pass the start
of the vectors as an argument to tramp_ventry.
Reviewed-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: James Morse <james.morse@arm.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
commit 6c5bf79b69f911560fbf82214c0971af6e58e682 upstream.
Systems using kpti enter and exit the kernel through a trampoline mapping
that is always mapped, even when the kernel is not. tramp_valias is a macro
to find the address of a symbol in the trampoline mapping.
Adding extra sets of vectors will expand the size of the entry.tramp.text
section to beyond 4K. tramp_valias will be unable to generate addresses
for symbols beyond 4K as it uses the 12 bit immediate of the add
instruction.
As there are now two registers available when tramp_alias is called,
use the extra register to avoid the 4K limit of the 12 bit immediate.
Reviewed-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: James Morse <james.morse@arm.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
commit c091fb6ae059cda563b2a4d93fdbc548ef34e1d6 upstream.
The trampoline code has a data page that holds the address of the vectors,
which is unmapped when running in user-space. This ensures that with
CONFIG_RANDOMIZE_BASE, the randomised address of the kernel can't be
discovered until after the kernel has been mapped.
If the trampoline text page is extended to include multiple sets of
vectors, it will be larger than a single page, making it tricky to
find the data page without knowing the size of the trampoline text
pages, which will vary with PAGE_SIZE.
Move the data page to appear before the text page. This allows the
data page to be found without knowing the size of the trampoline text
pages. 'tramp_vectors' is used to refer to the beginning of the
.entry.tramp.text section, do that explicitly.
Reviewed-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: James Morse <james.morse@arm.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
commit 03aff3a77a58b5b52a77e00537a42090ad57b80b upstream.
Kpti stashes x30 in far_el1 while it uses x30 for all its work.
Making the vectors a per-cpu data structure will require a second
register.
Allow tramp_exit two registers before it unmaps the kernel, by
leaving x30 on the stack, and stashing x29 in far_el1.
Reviewed-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: James Morse <james.morse@arm.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
commit d739da1694a0eaef0358a42b76904b611539b77b upstream.
Subsequent patches will add additional sets of vectors that use
the same tricks as the kpti vectors to reach the full-fat vectors.
The full-fat vectors contain some cleanup for kpti that is patched
in by alternatives when kpti is in use. Once there are additional
vectors, the cleanup will be needed in more cases.
But on big/little systems, the cleanup would be harmful if no
trampoline vector were in use. Instead of forcing CPUs that don't
need a trampoline vector to use one, make the trampoline cleanup
optional.
Entry at the top of the vectors will skip the cleanup. The trampoline
vectors can then skip the first instruction, triggering the cleanup
to run.
Reviewed-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: James Morse <james.morse@arm.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
commit 4330e2c5c04c27bebf89d34e0bc14e6943413067 upstream.
Subsequent patches add even more code to the ventry slots.
Ensure kernels that overflow a ventry slot don't get built.
Reviewed-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: James Morse <james.morse@arm.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
commit 9e45365f1469ef2b934f9d035975dbc9ad352116 upstream.
This is a new ID register, introduced in 8.7.
Signed-off-by: Joey Gouly <joey.gouly@arm.com>
Cc: Will Deacon <will@kernel.org>
Cc: Marc Zyngier <maz@kernel.org>
Cc: James Morse <james.morse@arm.com>
Cc: Alexandru Elisei <alexandru.elisei@arm.com>
Cc: Suzuki K Poulose <suzuki.poulose@arm.com>
Cc: Reiji Watanabe <reijiw@google.com>
Acked-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20211210165432.8106-3-joey.gouly@arm.com
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: James Morse <james.morse@arm.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
commit f1a54ae9af0da4d76239256ed640a93ab3aadac0 upstream.
Currently we lazily-initialize a module's ftrace PLT at runtime when we
install the first ftrace call. To do so we have to apply a number of
sanity checks, transiently mark the module text as RW, and perform an
IPI as part of handling Neoverse-N1 erratum #1542419.
We only expect the ftrace trampoline to point at ftrace_caller() (AKA
FTRACE_ADDR), so let's simplify all of this by intializing the PLT at
module load time, before the module loader marks the module RO and
performs the intial I-cache maintenance for the module.
Thus we can rely on the module having been correctly intialized, and can
simplify the runtime work necessary to install an ftrace call in a
module. This will also allow for the removal of module_disable_ro().
Tested by forcing ftrace_make_call() to use the module PLT, and then
loading up a module after setting up ftrace with:
| echo ":mod:<module-name>" > set_ftrace_filter;
| echo function > current_tracer;
| modprobe <module-name>
Since FTRACE_ADDR is only defined when CONFIG_DYNAMIC_FTRACE is
selected, we wrap its use along with most of module_init_ftrace_plt()
with ifdeffery rather than using IS_ENABLED().
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Reviewed-by: Amit Daniel Kachhap <amit.kachhap@arm.com>
Reviewed-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Reviewed-by: Torsten Duwe <duwe@suse.de>
Tested-by: Amit Daniel Kachhap <amit.kachhap@arm.com>
Tested-by: Torsten Duwe <duwe@suse.de>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: James Morse <james.morse@arm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Will Deacon <will@kernel.org>
Cc: Stephen Boyd <swboyd@chromium.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit bd8b21d3dd661658addc1cd4cc869bab11d28596 upstream.
When we load a module, we have to perform some special work for a couple
of named sections. To do this, we iterate over all of the module's
sections, and perform work for each section we recognize.
To make it easier to handle the unexpected absence of a section, and to
make the section-specific logic easer to read, let's factor the section
search into a helper. Similar is already done in the core module loader,
and other architectures (and ideally we'd unify these in future).
If we expect a module to have an ftrace trampoline section, but it
doesn't have one, we'll now reject loading the module. When
ARM64_MODULE_PLTS is selected, any correctly built module should have
one (and this is assumed by arm64's ftrace PLT code) and the absence of
such a section implies something has gone wrong at build time.
Subsequent patches will make use of the new helper.
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Reviewed-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Reviewed-by: Torsten Duwe <duwe@suse.de>
Tested-by: Amit Daniel Kachhap <amit.kachhap@arm.com>
Tested-by: Torsten Duwe <duwe@suse.de>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: James Morse <james.morse@arm.com>
Cc: Will Deacon <will@kernel.org>
Cc: Stephen Boyd <swboyd@chromium.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 38e0257e0e6f4fef2aa2966b089b56a8b1cfb75c upstream.
The erratum 1418040 workaround enables CNTVCT_EL1 access trapping in EL0
when executing compat threads. The workaround is applied when switching
between tasks, but the need for the workaround could also change at an
exec(), when a non-compat task execs a compat binary or vice versa. Apply
the workaround in arch_setup_new_exec().
This leaves a small window of time between SET_PERSONALITY and
arch_setup_new_exec where preemption could occur and confuse the old
workaround logic that compares TIF_32BIT between prev and next. Instead, we
can just read cntkctl to make sure it's in the state that the next task
needs. I measured cntkctl read time to be about the same as a mov from a
general-purpose register on N1. Update the workaround logic to examine the
current value of cntkctl instead of the previous task's compat state.
Fixes: d49f7d7376d0 ("arm64: Move handling of erratum 1418040 into C code")
Cc: <stable@vger.kernel.org> # 5.9.x
Signed-off-by: D Scott Phillips <scott@os.amperecomputing.com>
Reviewed-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20211220234114.3926-1-scott@os.amperecomputing.com
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit ff083a2d972f56bebfd82409ca62e5dfce950961 upstream.
Protect perf_guest_cbs with RCU to fix multiple possible errors. Luckily,
all paths that read perf_guest_cbs already require RCU protection, e.g. to
protect the callback chains, so only the direct perf_guest_cbs touchpoints
need to be modified.
Bug #1 is a simple lack of WRITE_ONCE/READ_ONCE behavior to ensure
perf_guest_cbs isn't reloaded between a !NULL check and a dereference.
Fixed via the READ_ONCE() in rcu_dereference().
Bug #2 is that on weakly-ordered architectures, updates to the callbacks
themselves are not guaranteed to be visible before the pointer is made
visible to readers. Fixed by the smp_store_release() in
rcu_assign_pointer() when the new pointer is non-NULL.
Bug #3 is that, because the callbacks are global, it's possible for
readers to run in parallel with an unregisters, and thus a module
implementing the callbacks can be unloaded while readers are in flight,
resulting in a use-after-free. Fixed by a synchronize_rcu() call when
unregistering callbacks.
Bug #1 escaped notice because it's extremely unlikely a compiler will
reload perf_guest_cbs in this sequence. perf_guest_cbs does get reloaded
for future derefs, e.g. for ->is_user_mode(), but the ->is_in_guest()
guard all but guarantees the consumer will win the race, e.g. to nullify
perf_guest_cbs, KVM has to completely exit the guest and teardown down
all VMs before KVM start its module unload / unregister sequence. This
also makes it all but impossible to encounter bug #3.
Bug #2 has not been a problem because all architectures that register
callbacks are strongly ordered and/or have a static set of callbacks.
But with help, unloading kvm_intel can trigger bug #1 e.g. wrapping
perf_guest_cbs with READ_ONCE in perf_misc_flags() while spamming
kvm_intel module load/unload leads to:
BUG: kernel NULL pointer dereference, address: 0000000000000000
#PF: supervisor read access in kernel mode
#PF: error_code(0x0000) - not-present page
PGD 0 P4D 0
Oops: 0000 [#1] PREEMPT SMP
CPU: 6 PID: 1825 Comm: stress Not tainted 5.14.0-rc2+ #459
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 0.0.0 02/06/2015
RIP: 0010:perf_misc_flags+0x1c/0x70
Call Trace:
perf_prepare_sample+0x53/0x6b0
perf_event_output_forward+0x67/0x160
__perf_event_overflow+0x52/0xf0
handle_pmi_common+0x207/0x300
intel_pmu_handle_irq+0xcf/0x410
perf_event_nmi_handler+0x28/0x50
nmi_handle+0xc7/0x260
default_do_nmi+0x6b/0x170
exc_nmi+0x103/0x130
asm_exc_nmi+0x76/0xbf
Fixes: 39447b386c84 ("perf: Enhance perf to allow for guest statistic collection from host")
Signed-off-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20211111020738.2512932-2-seanjc@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 14831fad73f5ac30ac61760487d95a538e6ab3cb upstream.
When running the following command without arm-linux-gnueabi-gcc in
one's $PATH, the following warning is observed:
$ ARCH=arm64 CROSS_COMPILE_COMPAT=arm-linux-gnueabi- make -j72 LLVM=1 mrproper
make[1]: arm-linux-gnueabi-gcc: No such file or directory
This is because KCONFIG is not run for mrproper, so CONFIG_CC_IS_CLANG
is not set, and we end up eagerly evaluating various variables that try
to invoke CC_COMPAT.
This is a similar problem to what was observed in
commit dc960bfeedb0 ("h8300: suppress error messages for 'make clean'")
Reported-by: Lucas Henneman <henneman@google.com>
Suggested-by: Masahiro Yamada <masahiroy@kernel.org>
Signed-off-by: Nick Desaulniers <ndesaulniers@google.com>
Reviewed-by: Vincenzo Frascino <vincenzo.frascino@arm.com>
Reviewed-by: Nathan Chancellor <nathan@kernel.org>
Tested-by: Nathan Chancellor <nathan@kernel.org>
Link: https://lore.kernel.org/r/20211019223646.1146945-4-ndesaulniers@google.com
Signed-off-by: Will Deacon <will@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[ Upstream commit 9fcb2e93f41c07a400885325e7dbdfceba6efaec ]
__stack_chk_guard is setup once while init stage and never changed
after that.
Although the modification of this variable at runtime will usually
cause the kernel to crash (so does the attacker), it should be marked
as __ro_after_init, and it should not affect performance if it is
placed in the ro_after_init section.
Signed-off-by: Dan Li <ashimida@linux.alibaba.com>
Acked-by: Mark Rutland <mark.rutland@arm.com>
Link: https://lore.kernel.org/r/1631612642-102881-1-git-send-email-ashimida@linux.alibaba.com
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit 4b92d4add5f6dcf21275185c997d6ecb800054cd ]
DEFINE_SMP_CALL_CACHE_FUNCTION() was usefel before the CPU hotplug rework
to ensure that the cache related functions are called on the upcoming CPU
because the notifier itself could run on any online CPU.
The hotplug state machine guarantees that the callbacks are invoked on the
upcoming CPU. So there is no need to have this SMP function call
obfuscation. That indirection was missed when the hotplug notifiers were
converted.
This also solves the problem of ARM64 init_cache_level() invoking ACPI
functions which take a semaphore in that context. That's invalid as SMP
function calls run with interrupts disabled. Running it just from the
callback in context of the CPU hotplug thread solves this.
Fixes: 8571890e1513 ("arm64: Add support for ACPI based firmware tables")
Reported-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Guenter Roeck <linux@roeck-us.net>
Acked-by: Will Deacon <will@kernel.org>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Link: https://lore.kernel.org/r/871r69ersb.ffs@tglx
Signed-off-by: Sasha Levin <sashal@kernel.org>
commit e35ac9d0b56e9efefaeeb84b635ea26c2839ea86 upstream.
When we need a buffer for SVE register state we call sve_alloc() to make
sure that one is there. In order to avoid repeated allocations and frees
we keep the buffer around unless we change vector length and just memset()
it to ensure a clean register state. The function that deals with this
takes the task to operate on as an argument, however in the case where we
do a memset() we initialise using the SVE state size for the current task
rather than the task passed as an argument.
This is only an issue in the case where we are setting the register state
for a task via ptrace and the task being configured has a different vector
length to the task tracing it. In the case where the buffer is larger in
the traced process we will leak old state from the traced process to
itself, in the case where the buffer is smaller in the traced process we
will overflow the buffer and corrupt memory.
Fixes: bc0ee4760364 ("arm64/sve: Core task context handling")
Cc: <stable@vger.kernel.org> # 4.15.x
Signed-off-by: Mark Brown <broonie@kernel.org>
Link: https://lore.kernel.org/r/20210909165356.10675-1-broonie@kernel.org
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 90268574a3e8a6b883bd802d702a2738577e1006 upstream.
The `compute_indices` and `populate_entries` macros operate on inclusive
bounds, and thus the `map_memory` macro which uses them also operates
on inclusive bounds.
We pass `_end` and `_idmap_text_end` to `map_memory`, but these are
exclusive bounds, and if one of these is sufficiently aligned (as a
result of kernel configuration, physical placement, and KASLR), then:
* In `compute_indices`, the computed `iend` will be in the page/block *after*
the final byte of the intended mapping.
* In `populate_entries`, an unnecessary entry will be created at the end
of each level of table. At the leaf level, this entry will map up to
SWAPPER_BLOCK_SIZE bytes of physical addresses that we did not intend
to map.
As we may map up to SWAPPER_BLOCK_SIZE bytes more than intended, we may
violate the boot protocol and map physical address past the 2MiB-aligned
end address we are permitted to map. As we map these with Normal memory
attributes, this may result in further problems depending on what these
physical addresses correspond to.
The final entry at each level may require an additional table at that
level. As EARLY_ENTRIES() calculates an inclusive bound, we allocate
enough memory for this.
Avoid the extraneous mapping by having map_memory convert the exclusive
end address to an inclusive end address by subtracting one, and do
likewise in EARLY_ENTRIES() when calculating the number of required
tables. For clarity, comments are updated to more clearly document which
boundaries the macros operate on. For consistency with the other
macros, the comments in map_memory are also updated to describe `vstart`
and `vend` as virtual addresses.
Fixes: 0370b31e4845 ("arm64: Extend early page table code to allow for larger kernels")
Cc: <stable@vger.kernel.org> # 4.16.x
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Cc: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Steve Capper <steve.capper@arm.com>
Cc: Will Deacon <will@kernel.org>
Acked-by: Will Deacon <will@kernel.org>
Link: https://lore.kernel.org/r/20210823101253.55567-1-mark.rutland@arm.com
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit e30e8d46cf605d216a799a28c77b8a41c328613a upstream.
Due to inconsistencies in the way we manipulate compat GPRs, we have a
few issues today:
* For audit and tracing, where error codes are handled as a (native)
long, negative error codes are expected to be sign-extended to the
native 64-bits, or they may fail to be matched correctly. Thus a
syscall which fails with an error may erroneously be identified as
failing.
* For ptrace, *all* compat return values should be sign-extended for
consistency with 32-bit arm, but we currently only do this for
negative return codes.
* As we may transiently set the upper 32 bits of some compat GPRs while
in the kernel, these can be sampled by perf, which is somewhat
confusing. This means that where a syscall returns a pointer above 2G,
this will be sign-extended, but will not be mistaken for an error as
error codes are constrained to the inclusive range [-4096, -1] where
no user pointer can exist.
To fix all of these, we must consistently use helpers to get/set the
compat GPRs, ensuring that we never write the upper 32 bits of the
return code, and always sign-extend when reading the return code. This
patch does so, with the following changes:
* We re-organise syscall_get_return_value() to always sign-extend for
compat tasks, and reimplement syscall_get_error() atop. We update
syscall_trace_exit() to use syscall_get_return_value().
* We consistently use syscall_set_return_value() to set the return
value, ensureing the upper 32 bits are never set unexpectedly.
* As the core audit code currently uses regs_return_value() rather than
syscall_get_return_value(), we special-case this for
compat_user_mode(regs) such that this will do the right thing. Going
forward, we should try to move the core audit code over to
syscall_get_return_value().
Cc: <stable@vger.kernel.org>
Reported-by: He Zhe <zhe.he@windriver.com>
Reported-by: weiyuchen <weiyuchen3@huawei.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will@kernel.org>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Link: https://lore.kernel.org/r/20210802104200.21390-1-mark.rutland@arm.com
Signed-off-by: Will Deacon <will@kernel.org>
[Mark: trivial conflict resolution for v5.4.y]
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[ Upstream commit 9163f01130304fab1f74683d7d44632da7bda637 ]
When using CONFIG_ARM64_SW_TTBR0_PAN, a task's thread_info::ttbr0 must be
the TTBR0_EL1 value used to run userspace. With 52-bit PAs, the PA must be
packed into the TTBR using phys_to_ttbr(), but we forget to do this in some
of the SW PAN code. Thus, if the value is installed into TTBR0_EL1 (as may
happen in the uaccess routines), this could result in UNPREDICTABLE
behaviour.
Since hardware with 52-bit PA support almost certainly has HW PAN, which
will be used in preference, this shouldn't be a practical issue, but let's
fix this for consistency.
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: James Morse <james.morse@arm.com>
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-kernel@vger.kernel.org
Fixes: 529c4b05a3cb ("arm64: handle 52-bit addresses in TTBR")
Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Link: https://lore.kernel.org/r/1623749578-11231-1-git-send-email-anshuman.khandual@arm.com
Signed-off-by: Will Deacon <will@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit 833be850f1cabd0e3b5337c0fcab20a6e936dd48 ]
Depending on configuration options and specific code paths, we either
use the empty_zero_page or the configuration-dependent reserved_ttbr0
as a reserved value for TTBR{0,1}_EL1.
To simplify this code, let's always allocate and use the same
reserved_pg_dir, replacing reserved_ttbr0. Note that this is allocated
(and hence pre-zeroed), and is also marked as read-only in the kernel
Image mapping.
Keeping this separate from the empty_zero_page potentially helps with
robustness as the empty_zero_page is used in a number of cases where a
failure to map it read-only could allow it to become corrupted.
The (presently unused) swapper_pg_end symbol is also removed, and
comments are added wherever we rely on the offsets between the
pre-allocated pg_dirs to keep these cases easily identifiable.
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Cc: Will Deacon <will@kernel.org>
Link: https://lore.kernel.org/r/20201103102229.8542-1-mark.rutland@arm.com
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit 388708028e6937f3fc5fc19aeeb847f8970f489c ]
The arm64 assembler in binutils 2.32 and above generates a program
property note in a note section, .note.gnu.property, to encode used x86
ISAs and features. But the kernel linker script only contains a single
NOTE segment:
PHDRS
{
text PT_LOAD FLAGS(5) FILEHDR PHDRS; /* PF_R|PF_X */
dynamic PT_DYNAMIC FLAGS(4); /* PF_R */
note PT_NOTE FLAGS(4); /* PF_R */
}
The NOTE segment generated by the vDSO linker script is aligned to 4 bytes.
But the .note.gnu.property section must be aligned to 8 bytes on arm64.
$ readelf -n vdso64.so
Displaying notes found in: .note
Owner Data size Description
Linux 0x00000004 Unknown note type: (0x00000000)
description data: 06 00 00 00
readelf: Warning: note with invalid namesz and/or descsz found at offset 0x20
readelf: Warning: type: 0x78, namesize: 0x00000100, descsize: 0x756e694c, alignment: 8
Since the note.gnu.property section in the vDSO is not checked by the
dynamic linker, discard the .note.gnu.property sections in the vDSO.
Similar to commit 4caffe6a28d31 ("x86/vdso: Discard .note.gnu.property
sections in vDSO"), but for arm64.
Signed-off-by: Bill Wendling <morbo@google.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Acked-by: Ard Biesheuvel <ardb@kernel.org>
Link: https://lore.kernel.org/r/20210423205159.830854-1-morbo@google.com
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit 1d676673d665fd2162e7e466dcfbe5373bfdb73e ]
Currently we advertise the ID_AA6DFR0_EL1.TRACEVER for the guest,
when the trace register accesses are trapped (CPTR_EL2.TTA == 1).
So, the guest will get an undefined instruction, if trusts the
ID registers and access one of the trace registers.
Lets be nice to the guest and hide the feature to avoid
unexpected behavior.
Even though this can be done at KVM sysreg emulation layer,
we do this by removing the TRACEVER from the sanitised feature
register field. This is fine as long as the ETM drivers
can handle the individual trace units separately, even
when there are differences among the CPUs.
Cc: Will Deacon <will@kernel.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20210323120647.454211-2-suzuki.poulose@arm.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit 141f8202cfa4192c3af79b6cbd68e7760bb01b5a ]
The ppos points to a position in the old kernel memory (and in case of
arm64 in the crash kernel since elfcorehdr is passed as a segment). The
function should update the ppos by the amount that was read. This bug is
not exposed by accident, but other platforms update this value properly.
So, fix it in ARM64 version of elfcorehdr_read() as well.
Signed-off-by: Pavel Tatashin <pasha.tatashin@soleen.com>
Fixes: e62aaeac426a ("arm64: kdump: provide /proc/vmcore file")
Reviewed-by: Tyler Hicks <tyhicks@linux.microsoft.com>
Link: https://lore.kernel.org/r/20210319205054.743368-1-pasha.tatashin@soleen.com
Signed-off-by: Will Deacon <will@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit 7ba8f2b2d652cd8d8a2ab61f4be66973e70f9f88 ]
52-bit VA kernels can run on hardware that is only 48-bit capable, but
configure the ID map as 52-bit by default. This was not a problem until
recently, because the special T0SZ value for a 52-bit VA space was never
programmed into the TCR register anwyay, and because a 52-bit ID map
happens to use the same number of translation levels as a 48-bit one.
This behavior was changed by commit 1401bef703a4 ("arm64: mm: Always update
TCR_EL1 from __cpu_set_tcr_t0sz()"), which causes the unsupported T0SZ
value for a 52-bit VA to be programmed into TCR_EL1. While some hardware
simply ignores this, Mark reports that Amberwing systems choke on this,
resulting in a broken boot. But even before that commit, the unsupported
idmap_t0sz value was exposed to KVM and used to program TCR_EL2 incorrectly
as well.
Given that we already have to deal with address spaces being either 48-bit
or 52-bit in size, the cleanest approach seems to be to simply default to
a 48-bit VA ID map, and only switch to a 52-bit one if the placement of the
kernel in DRAM requires it. This is guaranteed not to happen unless the
system is actually 52-bit VA capable.
Fixes: 90ec95cda91a ("arm64: mm: Introduce VA_BITS_MIN")
Reported-by: Mark Salter <msalter@redhat.com>
Link: http://lore.kernel.org/r/20210310003216.410037-1-msalter@redhat.com
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Link: https://lore.kernel.org/r/20210310171515.416643-2-ardb@kernel.org
Signed-off-by: Will Deacon <will@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
commit df84fe94708985cdfb78a83148322bcd0a699472 upstream.
Since commit f086f67485c5 ("arm64: ptrace: add support for syscall
emulation"), if system call number -1 is called and the process is being
traced with PTRACE_SYSCALL, for example by strace, the seccomp check is
skipped and -ENOSYS is returned unconditionally (unless altered by the
tracer) rather than carrying out action specified in the seccomp filter.
The consequence of this is that it is not possible to reliably strace
a seccomp based implementation of a foreign system call interface in
which r7/x8 is permitted to be -1 on entry to a system call.
Also trace_sys_enter and audit_syscall_entry are skipped if a system
call is skipped.
Fix by removing the in_syscall(regs) check restoring the previous
behaviour which is like AArch32, x86 (which uses generic code) and
everything else.
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Catalin Marinas<catalin.marinas@arm.com>
Cc: <stable@vger.kernel.org>
Fixes: f086f67485c5 ("arm64: ptrace: add support for syscall emulation")
Reviewed-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Sudeep Holla <sudeep.holla@arm.com>
Tested-by: Sudeep Holla <sudeep.holla@arm.com>
Signed-off-by: Timothy E Baldwin <T.E.Baldwin99@members.leeds.ac.uk>
Link: https://lore.kernel.org/r/90edd33b-6353-1228-791f-0336d94d5f8c@majoroak.me.uk
Signed-off-by: Will Deacon <will@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit f5c6d0fcf90ce07ee0d686d465b19b247ebd5ed7 upstream.
These plt* and .text.ftrace_trampoline sections specified for arm64 have
non-zero addressses. Non-zero section addresses in a relocatable ELF would
confuse GDB when it tries to compute the section offsets and it ends up
printing wrong symbol addresses. Therefore, set them to zero, which mirrors
the change in commit 5d8591bc0fba ("module: set ksymtab/kcrctab* section
addresses to 0x0").
Reported-by: Frank van der Linden <fllinden@amazon.com>
Signed-off-by: Shaoying Xu <shaoyi@amazon.com>
Cc: <stable@vger.kernel.org>
Link: https://lore.kernel.org/r/20210216183234.GA23876@amazon.com
Signed-off-by: Will Deacon <will@kernel.org>
[shaoyi@amazon.com: made same changes in arch/arm64/kernel/module.lds for 5.4]
Signed-off-by: Shaoying Xu <shaoyi@amazon.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit c0b15c25d25171db4b70cc0b7dbc1130ee94017d upstream.
The erratum 1024718 affects Cortex-A55 r0p0 to r2p0. However
we apply the work around for r0p0 - r1p0. Unfortunately this
won't be fixed for the future revisions for the CPU. Thus
extend the work around for all versions of A55, to cover
for r2p0 and any future revisions.
Cc: stable@vger.kernel.org
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will@kernel.org>
Cc: James Morse <james.morse@arm.com>
Cc: Kunihiko Hayashi <hayashi.kunihiko@socionext.com>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Link: https://lore.kernel.org/r/20210203230057.3961239-1-suzuki.poulose@arm.com
[will: Update Kconfig help text]
Signed-off-by: Will Deacon <will@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit d47422d953e258ad587b5edf2274eb95d08bdc7d upstream.
As stated in linux/errno.h, ENOTSUPP should never be seen by user programs.
When we set up uprobe with 32-bit perf and arm64 kernel, we would see the
following vague error without useful hint.
The sys_perf_event_open() syscall returned with 524 (INTERNAL ERROR:
strerror_r(524, [buf], 128)=22)
Use EOPNOTSUPP instead to indicate such cases.
Signed-off-by: He Zhe <zhe.he@windriver.com>
Link: https://lore.kernel.org/r/20210223082535.48730-1-zhe.he@windriver.com
Cc: <stable@vger.kernel.org>
Signed-off-by: Will Deacon <will@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 656d1d58d8e0958d372db86c24f0b2ea36f50888 upstream.
in function create_dtb(), if fdt_open_into() fails, we need to vfree
buf before return.
Fixes: 52b2a8af7436 ("arm64: kexec_file: load initrd and device-tree")
Cc: stable@vger.kernel.org # v5.0
Signed-off-by: qiuguorui1 <qiuguorui1@huawei.com>
Link: https://lore.kernel.org/r/20210218125900.6810-1-qiuguorui1@huawei.com
Signed-off-by: Will Deacon <will@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[ Upstream commit 9d41053e8dc115c92b8002c3db5f545d7602498b ]
Although there has been a bit of back and forth on the subject, it
appears that invalidating TLBs requires an ISB instruction when FEAT_ETS
is not implemented by the CPU.
From the bible:
| In an implementation that does not implement FEAT_ETS, a TLB
| maintenance instruction executed by a PE, PEx, can complete at any
| time after it is issued, but is only guaranteed to be finished for a
| PE, PEx, after the execution of DSB by the PEx followed by a Context
| synchronization event
Add the missing ISB in __primary_switch, just in case.
Fixes: 3c5e9f238bc4 ("arm64: head.S: move KASLR processing out of __enable_mmu()")
Suggested-by: Will Deacon <will@kernel.org>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Acked-by: Mark Rutland <mark.rutland@arm.com>
Link: https://lore.kernel.org/r/20210224093738.3629662-3-maz@kernel.org
Signed-off-by: Will Deacon <will@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit ca1314d73eed493c49bb1932c60a8605530db2e4 ]
In el0_svc_common() we unmask exceptions before we call user_exit(), and
so there's a window where an IRQ or debug exception can be taken while
RCU is not watching. In do_debug_exception() we account for this in via
debug_exception_{enter,exit}(), but in the el1_irq asm we do not and we
call trace functions which rely on RCU before we have a guarantee that
RCU is watching.
Let's avoid this by having el0_svc_common() exit userspace before
unmasking exceptions, matching what we do for all other EL0 entry paths.
We can use user_exit_irqoff() to avoid the pointless save/restore of IRQ
flags while we're sure exceptions are masked in DAIF.
The workaround for Cortex-A76 erratum 1463225 may trigger a debug
exception before this point, but the debug code invoked in this case is
safe even when RCU is not watching.
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: James Morse <james.morse@arm.com>
Cc: Will Deacon <will@kernel.org>
Link: https://lore.kernel.org/r/20201130115950.22492-2-mark.rutland@arm.com
Signed-off-by: Will Deacon <will@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit 04e613ded8c26489b3e0f9101b44462f780d1a35 ]
Commit ce3d31ad3cac ("arm64/smp: Move rcu_cpu_starting() earlier") ensured
that RCU is informed early about incoming CPUs that might end up calling
into printk() before they are online. However, if such a CPU fails the
early CPU feature compatibility checks in check_local_cpu_capabilities(),
then it will be powered off or parked without informing RCU, leading to
an endless stream of stalls:
| rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
| rcu: 2-O...: (0 ticks this GP) idle=002/1/0x4000000000000000 softirq=0/0 fqs=2593
| (detected by 0, t=5252 jiffies, g=9317, q=136)
| Task dump for CPU 2:
| task:swapper/2 state:R running task stack: 0 pid: 0 ppid: 1 flags:0x00000028
| Call trace:
| ret_from_fork+0x0/0x30
Ensure that the dying CPU invokes rcu_report_dead() prior to being powered
off or parked.
Cc: Qian Cai <cai@redhat.com>
Cc: "Paul E. McKenney" <paulmck@kernel.org>
Reviewed-by: Paul E. McKenney <paulmck@kernel.org>
Suggested-by: Qian Cai <cai@redhat.com>
Link: https://lore.kernel.org/r/20201105222242.GA8842@willie-the-truck
Link: https://lore.kernel.org/r/20201106103602.9849-3-will@kernel.org
Signed-off-by: Will Deacon <will@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit 891deb87585017d526b67b59c15d38755b900fea ]
cpu_psci_cpu_die() is called in the context of the dying CPU, which
will no longer be online or tracked by RCU. It is therefore not generally
safe to call printk() if the PSCI "cpu off" request fails, so remove the
pr_crit() invocation.
Cc: Qian Cai <cai@redhat.com>
Cc: "Paul E. McKenney" <paulmck@kernel.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Link: https://lore.kernel.org/r/20201106103602.9849-2-will@kernel.org
Signed-off-by: Will Deacon <will@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit f969f03888b9438fdb227b6460d99ede5737326d ]
In a surprising turn of events, it transpires that CPU capabilities
configured as ARM64_CPUCAP_WEAK_LOCAL_CPU_FEATURE are never set as the
result of late-onlining. Therefore our handling of erratum 1418040 does
not get activated if it is not required by any of the boot CPUs, even
though we allow late-onlining of an affected CPU.
In order to get things working again, replace the cpus_have_const_cap()
invocation with an explicit check for the current CPU using
this_cpu_has_cap().
Cc: Sai Prakash Ranjan <saiprakash.ranjan@codeaurora.org>
Cc: Stephen Boyd <swboyd@chromium.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Reviewed-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Acked-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20201106114952.10032-1-will@kernel.org
Signed-off-by: Will Deacon <will@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit ce3d31ad3cac765484463b4f5a0b6b1f8f1a963e ]
The call to rcu_cpu_starting() in secondary_start_kernel() is not early
enough in the CPU-hotplug onlining process, which results in lockdep
splats as follows:
WARNING: suspicious RCU usage
-----------------------------
kernel/locking/lockdep.c:3497 RCU-list traversed in non-reader section!!
other info that might help us debug this:
RCU used illegally from offline CPU!
rcu_scheduler_active = 1, debug_locks = 1
no locks held by swapper/1/0.
Call trace:
dump_backtrace+0x0/0x3c8
show_stack+0x14/0x60
dump_stack+0x14c/0x1c4
lockdep_rcu_suspicious+0x134/0x14c
__lock_acquire+0x1c30/0x2600
lock_acquire+0x274/0xc48
_raw_spin_lock+0xc8/0x140
vprintk_emit+0x90/0x3d0
vprintk_default+0x34/0x40
vprintk_func+0x378/0x590
printk+0xa8/0xd4
__cpuinfo_store_cpu+0x71c/0x868
cpuinfo_store_cpu+0x2c/0xc8
secondary_start_kernel+0x244/0x318
This is avoided by moving the call to rcu_cpu_starting up near the
beginning of the secondary_start_kernel() function.
Signed-off-by: Qian Cai <cai@redhat.com>
Acked-by: Paul E. McKenney <paulmck@kernel.org>
Link: https://lore.kernel.org/lkml/160223032121.7002.1269740091547117869.tip-bot2@tip-bot2/
Link: https://lore.kernel.org/r/20201028182614.13655-1-cai@redhat.com
Signed-off-by: Will Deacon <will@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
