IF YOU WOULD LIKE TO GET AN ACCOUNT, please write an
email to Administrator. User accounts are meant only to access repo
and report issues and/or generate pull requests.
This is a purpose-specific Git hosting for
BaseALT
projects. Thank you for your understanding!
Только зарегистрированные пользователи имеют доступ к сервису!
Для получения аккаунта, обратитесь к администратору.
Let GCC know that only the low 16 bits of load_gs_index() argument
actually matter. It might allow it to create slightly better
code. However, do not propagate this into the prototypes of functions
that end up being paravirtualized, to avoid unnecessary changes.
Signed-off-by: H. Peter Anvin (Intel) <hpa@zytor.com>
Signed-off-by: Xin Li <xin3.li@intel.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/20230112072032.35626-4-xin3.li@intel.com
To address the Intel SKL RSB underflow issue in software it's required to
do call depth tracking.
Provide a return thunk for call depth tracking on Intel SKL CPUs.
The tracking does not use a counter. It uses uses arithmetic shift
right on call entry and logical shift left on return.
The depth tracking variable is initialized to 0x8000.... when the call
depth is zero. The arithmetic shift right sign extends the MSB and
saturates after the 12th call. The shift count is 5 so the tracking covers
12 nested calls. On return the variable is shifted left logically so it
becomes zero again.
CALL RET
0: 0x8000000000000000 0x0000000000000000
1: 0xfc00000000000000 0xf000000000000000
...
11: 0xfffffffffffffff8 0xfffffffffffffc00
12: 0xffffffffffffffff 0xffffffffffffffe0
After a return buffer fill the depth is credited 12 calls before the next
stuffing has to take place.
There is a inaccuracy for situations like this:
10 calls
5 returns
3 calls
4 returns
3 calls
....
The shift count might cause this to be off by one in either direction, but
there is still a cushion vs. the RSB depth. The algorithm does not claim to
be perfect, but it should obfuscate the problem enough to make exploitation
extremly difficult.
The theory behind this is:
RSB is a stack with depth 16 which is filled on every call. On the return
path speculation "pops" entries to speculate down the call chain. Once the
speculative RSB is empty it switches to other predictors, e.g. the Branch
History Buffer, which can be mistrained by user space and misguide the
speculation path to a gadget.
Call depth tracking is designed to break this speculation path by stuffing
speculation trap calls into the RSB which are never getting a corresponding
return executed. This stalls the prediction path until it gets resteered,
The assumption is that stuffing at the 12th return is sufficient to break
the speculation before it hits the underflow and the fallback to the other
predictors. Testing confirms that it works. Johannes, one of the retbleed
researchers. tried to attack this approach but failed.
There is obviously no scientific proof that this will withstand future
research progress, but all we can do right now is to speculate about it.
The SAR/SHL usage was suggested by Andi Kleen.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/r/20220915111147.890071690@infradead.org
paranoid_entry(), error_entry() and xen_error_entry() have to be
exempted from call accounting by thunk patching because they are
before UNTRAIN_RET.
Expose them so they are available in the alternative code.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/r/20220915111147.265598113@infradead.org
No point in having a call there. Spare the call/ret overhead.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/r/20220915111146.539578813@infradead.org
It turns out that 'stack_canary_offset' is a variable name; shadowing
that with a #define is ripe of fail when the asm-offsets.h header gets
included. Rename the thing.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Extend the struct pcpu_hot cacheline with current_top_of_stack;
another very frequently used value.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/r/20220915111145.493038635@infradead.org
UNTRAIN_RET is not needed in native_irq_return_ldt because RET
untraining has already been done at this point.
In addition, when the RETBleed mitigation is IBPB, UNTRAIN_RET clobbers
several registers (AX, CX, DX) so here it trashes user values which are
in these registers.
Signed-off-by: Alexandre Chartre <alexandre.chartre@oracle.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lore.kernel.org/r/35b0d50f-12d1-10c3-f5e8-d6c140486d4a@oracle.com
Commit
ee774dac0da1 ("x86/entry: Move PUSH_AND_CLEAR_REGS out of error_entry()")
moved PUSH_AND_CLEAR_REGS out of error_entry, into its own function, in
part to avoid calling error_entry() for XenPV.
However, commit
7c81c0c9210c ("x86/entry: Avoid very early RET")
had to change that because the 'ret' was too early and moved it into
idtentry, bloating the text size, since idtentry is expanded for every
exception vector.
However, with the advent of xen_error_entry() in commit
d147553b64bad ("x86/xen: Add UNTRAIN_RET")
it became possible to remove PUSH_AND_CLEAR_REGS from idtentry, back
into *error_entry().
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Borislav Petkov <bp@suse.de>
If a kernel is built with CONFIG_RETPOLINE=n, but the user still wants
to mitigate Spectre v2 using IBRS or eIBRS, the RSB filling will be
silently disabled.
There's nothing retpoline-specific about RSB buffer filling. Remove the
CONFIG_RETPOLINE guards around it.
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Borislav Petkov <bp@suse.de>
Since entry asm is tricky, add a validation pass that ensures the
retbleed mitigation has been done before the first actual RET
instruction.
Entry points are those that either have UNWIND_HINT_ENTRY, which acts
as UNWIND_HINT_EMPTY but marks the instruction as an entry point, or
those that have UWIND_HINT_IRET_REGS at +0.
This is basically a variant of validate_branch() that is
intra-function and it will simply follow all branches from marked
entry points and ensures that all paths lead to ANNOTATE_UNRET_END.
If a path hits RET or an indirection the path is a fail and will be
reported.
There are 3 ANNOTATE_UNRET_END instances:
- UNTRAIN_RET itself
- exception from-kernel; this path doesn't need UNTRAIN_RET
- all early exceptions; these also don't need UNTRAIN_RET
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Josh Poimboeuf <jpoimboe@kernel.org>
Signed-off-by: Borislav Petkov <bp@suse.de>
Implement Kernel IBRS - currently the only known option to mitigate RSB
underflow speculation issues on Skylake hardware.
Note: since IBRS_ENTER requires fuller context established than
UNTRAIN_RET, it must be placed after it. However, since UNTRAIN_RET
itself implies a RET, it must come after IBRS_ENTER. This means
IBRS_ENTER needs to also move UNTRAIN_RET.
Note 2: KERNEL_IBRS is sub-optimal for XenPV.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Josh Poimboeuf <jpoimboe@kernel.org>
Signed-off-by: Borislav Petkov <bp@suse.de>
Note: needs to be in a section distinct from Retpolines such that the
Retpoline RET substitution cannot possibly use immediate jumps.
ORC unwinding for zen_untrain_ret() and __x86_return_thunk() is a
little tricky but works due to the fact that zen_untrain_ret() doesn't
have any stack ops and as such will emit a single ORC entry at the
start (+0x3f).
Meanwhile, unwinding an IP, including the __x86_return_thunk() one
(+0x40) will search for the largest ORC entry smaller or equal to the
IP, these will find the one ORC entry (+0x3f) and all works.
[ Alexandre: SVM part. ]
[ bp: Build fix, massages. ]
Suggested-by: Andrew Cooper <Andrew.Cooper3@citrix.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Josh Poimboeuf <jpoimboe@kernel.org>
Signed-off-by: Borislav Petkov <bp@suse.de>
Commit
ee774dac0da1 ("x86/entry: Move PUSH_AND_CLEAR_REGS out of error_entry()")
manages to introduce a CALL/RET pair that is before SWITCH_TO_KERNEL_CR3,
which means it is before RETBleed can be mitigated.
Revert to an earlier version of the commit in Fixes. Down side is that
this will bloat .text size somewhat. The alternative is fully reverting
it.
The purpose of this patch was to allow migrating error_entry() to C,
including the whole of kPTI. Much care needs to be taken moving that
forward to not re-introduce this problem of early RETs.
Fixes: ee774dac0da1 ("x86/entry: Move PUSH_AND_CLEAR_REGS out of error_entry()")
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Josh Poimboeuf <jpoimboe@kernel.org>
Signed-off-by: Borislav Petkov <bp@suse.de>
conventions so that former can be converted to C eventually
- Simplify PUSH_AND_CLEAR_REGS so that it can be used at the system call
entry paths instead of having opencoded, slightly different variants of it
everywhere
- Misc other fixes
-----BEGIN PGP SIGNATURE-----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=P80f
-----END PGP SIGNATURE-----
Merge tag 'x86_asm_for_v5.19_rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 asm updates from Borislav Petkov:
- A bunch of changes towards streamlining low level asm helpers'
calling conventions so that former can be converted to C eventually
- Simplify PUSH_AND_CLEAR_REGS so that it can be used at the system
call entry paths instead of having opencoded, slightly different
variants of it everywhere
- Misc other fixes
* tag 'x86_asm_for_v5.19_rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/entry: Fix register corruption in compat syscall
objtool: Fix STACK_FRAME_NON_STANDARD reloc type
linkage: Fix issue with missing symbol size
x86/entry: Remove skip_r11rcx
x86/entry: Use PUSH_AND_CLEAR_REGS for compat
x86/entry: Simplify entry_INT80_compat()
x86/mm: Simplify RESERVE_BRK()
x86/entry: Convert SWAPGS to swapgs and remove the definition of SWAPGS
x86/entry: Don't call error_entry() for XENPV
x86/entry: Move CLD to the start of the idtentry macro
x86/entry: Move PUSH_AND_CLEAR_REGS out of error_entry()
x86/entry: Switch the stack after error_entry() returns
x86/traps: Use pt_regs directly in fixup_bad_iret()
Add to confidential guests the necessary memory integrity protection
against malicious hypervisor-based attacks like data replay, memory
remapping and others, thus achieving a stronger isolation from the
hypervisor.
At the core of the functionality is a new structure called a reverse
map table (RMP) with which the guest has a say in which pages get
assigned to it and gets notified when a page which it owns, gets
accessed/modified under the covers so that the guest can take an
appropriate action.
In addition, add support for the whole machinery needed to launch a SNP
guest, details of which is properly explained in each patch.
And last but not least, the series refactors and improves parts of the
previous SEV support so that the new code is accomodated properly and
not just bolted on.
-----BEGIN PGP SIGNATURE-----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=Y8kW
-----END PGP SIGNATURE-----
Merge tag 'x86_sev_for_v5.19_rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull AMD SEV-SNP support from Borislav Petkov:
"The third AMD confidential computing feature called Secure Nested
Paging.
Add to confidential guests the necessary memory integrity protection
against malicious hypervisor-based attacks like data replay, memory
remapping and others, thus achieving a stronger isolation from the
hypervisor.
At the core of the functionality is a new structure called a reverse
map table (RMP) with which the guest has a say in which pages get
assigned to it and gets notified when a page which it owns, gets
accessed/modified under the covers so that the guest can take an
appropriate action.
In addition, add support for the whole machinery needed to launch a
SNP guest, details of which is properly explained in each patch.
And last but not least, the series refactors and improves parts of the
previous SEV support so that the new code is accomodated properly and
not just bolted on"
* tag 'x86_sev_for_v5.19_rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (60 commits)
x86/entry: Fixup objtool/ibt validation
x86/sev: Mark the code returning to user space as syscall gap
x86/sev: Annotate stack change in the #VC handler
x86/sev: Remove duplicated assignment to variable info
x86/sev: Fix address space sparse warning
x86/sev: Get the AP jump table address from secrets page
x86/sev: Add missing __init annotations to SEV init routines
virt: sevguest: Rename the sevguest dir and files to sev-guest
virt: sevguest: Change driver name to reflect generic SEV support
x86/boot: Put globals that are accessed early into the .data section
x86/boot: Add an efi.h header for the decompressor
virt: sevguest: Fix bool function returning negative value
virt: sevguest: Fix return value check in alloc_shared_pages()
x86/sev-es: Replace open-coded hlt-loop with sev_es_terminate()
virt: sevguest: Add documentation for SEV-SNP CPUID Enforcement
virt: sevguest: Add support to get extended report
virt: sevguest: Add support to derive key
virt: Add SEV-SNP guest driver
x86/sev: Register SEV-SNP guest request platform device
x86/sev: Provide support for SNP guest request NAEs
...
Commit
47f33de4aafb ("x86/sev: Mark the code returning to user space as syscall gap")
added a bunch of text references without annotating them, resulting in a
spree of objtool complaints:
vmlinux.o: warning: objtool: vc_switch_off_ist+0x77: relocation to !ENDBR: entry_SYSCALL_64+0x15c
vmlinux.o: warning: objtool: vc_switch_off_ist+0x8f: relocation to !ENDBR: entry_SYSCALL_compat+0xa5
vmlinux.o: warning: objtool: vc_switch_off_ist+0x97: relocation to !ENDBR: .entry.text+0x21ea
vmlinux.o: warning: objtool: vc_switch_off_ist+0xef: relocation to !ENDBR: .entry.text+0x162
vmlinux.o: warning: objtool: __sev_es_ist_enter+0x60: relocation to !ENDBR: entry_SYSCALL_64+0x15c
vmlinux.o: warning: objtool: __sev_es_ist_enter+0x6c: relocation to !ENDBR: .entry.text+0x162
vmlinux.o: warning: objtool: __sev_es_ist_enter+0x8a: relocation to !ENDBR: entry_SYSCALL_compat+0xa5
vmlinux.o: warning: objtool: __sev_es_ist_enter+0xc1: relocation to !ENDBR: .entry.text+0x21ea
Since these text references are used to compare against IP, and are not
an indirect call target, they don't need ENDBR so annotate them away.
Fixes: 47f33de4aafb ("x86/sev: Mark the code returning to user space as syscall gap")
Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lore.kernel.org/r/20220520082604.GQ2578@worktop.programming.kicks-ass.net
When returning to user space, %rsp is user-controlled value.
If it is a SNP-guest and the hypervisor decides to mess with the
code-page for this path while a CPU is executing it, a potential #VC
could hit in the syscall return path and mislead the #VC handler.
So make ip_within_syscall_gap() return true in this case.
Signed-off-by: Lai Jiangshan <jiangshan.ljs@antgroup.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Acked-by: Joerg Roedel <jroedel@suse.de>
Link: https://lore.kernel.org/r/20220412124909.10467-1-jiangshanlai@gmail.com
In idtentry_vc(), vc_switch_off_ist() determines a safe stack to
switch to, off of the IST stack. Annotate the new stack switch with
ENCODE_FRAME_POINTER in case UNWINDER_FRAME_POINTER is used.
A stack walk before looks like this:
CPU: 0 PID: 0 Comm: swapper Not tainted 5.18.0-rc7+ #2
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 0.0.0 02/06/2015
Call Trace:
<TASK>
dump_stack_lvl
dump_stack
kernel_exc_vmm_communication
asm_exc_vmm_communication
? native_read_msr
? __x2apic_disable.part.0
? x2apic_setup
? cpu_init
? trap_init
? start_kernel
? x86_64_start_reservations
? x86_64_start_kernel
? secondary_startup_64_no_verify
</TASK>
and with the fix, the stack dump is exact:
CPU: 0 PID: 0 Comm: swapper Not tainted 5.18.0-rc7+ #3
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 0.0.0 02/06/2015
Call Trace:
<TASK>
dump_stack_lvl
dump_stack
kernel_exc_vmm_communication
asm_exc_vmm_communication
RIP: 0010:native_read_msr
Code: ...
< snipped regs >
? __x2apic_disable.part.0
x2apic_setup
cpu_init
trap_init
start_kernel
x86_64_start_reservations
x86_64_start_kernel
secondary_startup_64_no_verify
</TASK>
[ bp: Test in a SEV-ES guest and rewrite the commit message to
explain what exactly this does. ]
Fixes: a13644f3a53d ("x86/entry/64: Add entry code for #VC handler")
Signed-off-by: Lai Jiangshan <jiangshan.ljs@antgroup.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Acked-by: Josh Poimboeuf <jpoimboe@redhat.com>
Link: https://lore.kernel.org/r/20220316041612.71357-1-jiangshanlai@gmail.com
Yes, r11 and rcx have been restored previously, but since they're being
popped anyway (into rsi) might as well pop them into their own regs --
setting them to the value they already are.
Less magical code.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lore.kernel.org/r/20220506121631.365070674@infradead.org
XENPV doesn't use swapgs_restore_regs_and_return_to_usermode(),
error_entry() and the code between entry_SYSENTER_compat() and
entry_SYSENTER_compat_after_hwframe.
Change the PV-compatible SWAPGS to the ASM instruction swapgs in these
places.
Also remove the definition of SWAPGS since no more users.
Signed-off-by: Lai Jiangshan <jiangshan.ljs@antgroup.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Juergen Gross <jgross@suse.com>
Link: https://lore.kernel.org/r/20220503032107.680190-7-jiangshanlai@gmail.com
XENPV guests enter already on the task stack and they can't fault for
native_iret() nor native_load_gs_index() since they use their own pvop
for IRET and load_gs_index(). A CR3 switch is not needed either.
So there is no reason to call error_entry() in XENPV.
[ bp: Massage commit message. ]
Signed-off-by: Lai Jiangshan <jiangshan.ljs@antgroup.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Juergen Gross <jgross@suse.com>
Link: https://lore.kernel.org/r/20220503032107.680190-6-jiangshanlai@gmail.com
The macro idtentry() (through idtentry_body()) calls error_entry()
unconditionally even on XENPV. But XENPV needs to only push and clear
regs.
PUSH_AND_CLEAR_REGS in error_entry() makes the stack not return to its
original place when the function returns, which means it is not possible
to convert it to a C function.
Carve out PUSH_AND_CLEAR_REGS out of error_entry() and into a separate
function and call it before error_entry() in order to avoid calling
error_entry() on XENPV.
It will also allow for error_entry() to be converted to C code that can
use inlined sync_regs() and save a function call.
[ bp: Massage commit message. ]
Signed-off-by: Lai Jiangshan <jiangshan.ljs@antgroup.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Juergen Gross <jgross@suse.com>
Link: https://lore.kernel.org/r/20220503032107.680190-4-jiangshanlai@gmail.com
error_entry() calls fixup_bad_iret() before sync_regs() if it is a fault
from a bad IRET, to copy pt_regs to the kernel stack. It switches to the
kernel stack directly after sync_regs().
But error_entry() itself is also a function call, so it has to stash
the address it is going to return to, in %r12 which is unnecessarily
complicated.
Move the stack switching after error_entry() and get rid of the need to
handle the return address.
[ bp: Massage commit message. ]
Signed-off-by: Lai Jiangshan <jiangshan.ljs@antgroup.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lore.kernel.org/r/20220503032107.680190-3-jiangshanlai@gmail.com
Always stash the address error_entry() is going to return to, in %r12
and get rid of the void *error_entry_ret; slot in struct bad_iret_stack
which was supposed to account for it and pt_regs pushed on the stack.
After this, both fixup_bad_iret() and sync_regs() can work on a struct
pt_regs pointer directly.
[ bp: Rewrite commit message, touch ups. ]
Signed-off-by: Lai Jiangshan <jiangshan.ljs@antgroup.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lore.kernel.org/r/20220503032107.680190-2-jiangshanlai@gmail.com
Objtool can figure out that some \cfunc()s are noreturn and then
complains about certain instances having unreachable tails:
vmlinux.o: warning: objtool: asm_exc_xen_unknown_trap()+0x16: unreachable instruction
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Josh Poimboeuf <jpoimboe@redhat.com>
Link: https://lore.kernel.org/r/20220408094718.441854969@infradead.org
Annotate away some of the generic code references. This is things
where we take the address of a symbol for exception handling or return
addresses (eg. context switch).
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Josh Poimboeuf <jpoimboe@redhat.com>
Link: https://lore.kernel.org/r/20220308154318.877758523@infradead.org
Kernel entry points should be having ENDBR on for IBT configs.
The SYSCALL entry points are found through taking their respective
address in order to program them in the MSRs, while the exception
entry points are found through UNWIND_HINT_IRET_REGS.
The rule is that any UNWIND_HINT_IRET_REGS at sym+0 should have an
ENDBR, see the later objtool ibt validation patch.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Josh Poimboeuf <jpoimboe@redhat.com>
Link: https://lore.kernel.org/r/20220308154317.933157479@infradead.org
Even though Xen currently doesn't advertise IBT, prepare for when it
will eventually do so and sprinkle the ENDBR dust accordingly.
Even though most of the entry points are IRET like, the CPL0
Hypervisor can set WAIT-FOR-ENDBR and demand ENDBR at these sites.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Josh Poimboeuf <jpoimboe@redhat.com>
Link: https://lore.kernel.org/r/20220308154317.873919996@infradead.org
By doing an early rewrite of 'jmp native_iret` in
restore_regs_and_return_to_kernel() we can get rid of the last
INTERRUPT_RETURN user and paravirt_iret.
Suggested-by: Andrew Cooper <Andrew.Cooper3@citrix.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Josh Poimboeuf <jpoimboe@redhat.com>
Link: https://lore.kernel.org/r/20220308154317.815039833@infradead.org
Since commit 5c8f6a2e316e ("x86/xen: Add
xenpv_restore_regs_and_return_to_usermode()") Xen will no longer reach
this code and we can do away with the paravirt
SWAPGS/INTERRUPT_RETURN.
Suggested-by: Andrew Cooper <Andrew.Cooper3@citrix.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Josh Poimboeuf <jpoimboe@redhat.com>
Link: https://lore.kernel.org/r/20220308154317.756014488@infradead.org
Pull signal/exit/ptrace updates from Eric Biederman:
"This set of changes deletes some dead code, makes a lot of cleanups
which hopefully make the code easier to follow, and fixes bugs found
along the way.
The end-game which I have not yet reached yet is for fatal signals
that generate coredumps to be short-circuit deliverable from
complete_signal, for force_siginfo_to_task not to require changing
userspace configured signal delivery state, and for the ptrace stops
to always happen in locations where we can guarantee on all
architectures that the all of the registers are saved and available on
the stack.
Removal of profile_task_ext, profile_munmap, and profile_handoff_task
are the big successes for dead code removal this round.
A bunch of small bug fixes are included, as most of the issues
reported were small enough that they would not affect bisection so I
simply added the fixes and did not fold the fixes into the changes
they were fixing.
There was a bug that broke coredumps piped to systemd-coredump. I
dropped the change that caused that bug and replaced it entirely with
something much more restrained. Unfortunately that required some
rebasing.
Some successes after this set of changes: There are few enough calls
to do_exit to audit in a reasonable amount of time. The lifetime of
struct kthread now matches the lifetime of struct task, and the
pointer to struct kthread is no longer stored in set_child_tid. The
flag SIGNAL_GROUP_COREDUMP is removed. The field group_exit_task is
removed. Issues where task->exit_code was examined with
signal->group_exit_code should been examined were fixed.
There are several loosely related changes included because I am
cleaning up and if I don't include them they will probably get lost.
The original postings of these changes can be found at:
https://lkml.kernel.org/r/87a6ha4zsd.fsf@email.froward.int.ebiederm.org
https://lkml.kernel.org/r/87bl1kunjj.fsf@email.froward.int.ebiederm.org
https://lkml.kernel.org/r/87r19opkx1.fsf_-_@email.froward.int.ebiederm.org
I trimmed back the last set of changes to only the obviously correct
once. Simply because there was less time for review than I had hoped"
* 'signal-for-v5.17' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace: (44 commits)
ptrace/m68k: Stop open coding ptrace_report_syscall
ptrace: Remove unused regs argument from ptrace_report_syscall
ptrace: Remove second setting of PT_SEIZED in ptrace_attach
taskstats: Cleanup the use of task->exit_code
exit: Use the correct exit_code in /proc/<pid>/stat
exit: Fix the exit_code for wait_task_zombie
exit: Coredumps reach do_group_exit
exit: Remove profile_handoff_task
exit: Remove profile_task_exit & profile_munmap
signal: clean up kernel-doc comments
signal: Remove the helper signal_group_exit
signal: Rename group_exit_task group_exec_task
coredump: Stop setting signal->group_exit_task
signal: Remove SIGNAL_GROUP_COREDUMP
signal: During coredumps set SIGNAL_GROUP_EXIT in zap_process
signal: Make coredump handling explicit in complete_signal
signal: Have prepare_signal detect coredumps using signal->core_state
signal: Have the oom killer detect coredumps using signal->core_state
exit: Move force_uaccess back into do_exit
exit: Guarantee make_task_dead leaks the tsk when calling do_task_exit
...
There are two big uses of do_exit. The first is it's design use to be
the guts of the exit(2) system call. The second use is to terminate
a task after something catastrophic has happened like a NULL pointer
in kernel code.
Add a function make_task_dead that is initialy exactly the same as
do_exit to cover the cases where do_exit is called to handle
catastrophic failure. In time this can probably be reduced to just a
light wrapper around do_task_dead. For now keep it exactly the same so
that there will be no behavioral differences introducing this new
concept.
Replace all of the uses of do_exit that use it for catastraphic
task cleanup with make_task_dead to make it clear what the code
is doing.
As part of this rename rewind_stack_do_exit
rewind_stack_and_make_dead.
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Place the anonymous .fixup code at the tail of the regular functions.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Josh Poimboeuf <jpoimboe@redhat.com>
Reviewed-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Lai Jiangshan <jiangshanlai@gmail.com>
Link: https://lore.kernel.org/r/20211110101325.186049322@infradead.org
Replace all ret/retq instructions with RET in preparation of making
RET a macro. Since AS is case insensitive it's a big no-op without
RET defined.
find arch/x86/ -name \*.S | while read file
do
sed -i 's/\<ret[q]*\>/RET/' $file
done
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lore.kernel.org/r/20211204134907.905503893@infradead.org
In the native case, PER_CPU_VAR(cpu_tss_rw + TSS_sp0) is the
trampoline stack. But XEN pv doesn't use trampoline stack, so
PER_CPU_VAR(cpu_tss_rw + TSS_sp0) is also the kernel stack.
In that case, source and destination stacks are identical, which means
that reusing swapgs_restore_regs_and_return_to_usermode() in XEN pv
would cause %rsp to move up to the top of the kernel stack and leave the
IRET frame below %rsp.
This is dangerous as it can be corrupted if #NMI / #MC hit as either of
these events occurring in the middle of the stack pushing would clobber
data on the (original) stack.
And, with XEN pv, swapgs_restore_regs_and_return_to_usermode() pushing
the IRET frame on to the original address is useless and error-prone
when there is any future attempt to modify the code.
[ bp: Massage commit message. ]
Fixes: 7f2590a110b8 ("x86/entry/64: Use a per-CPU trampoline stack for IDT entries")
Signed-off-by: Lai Jiangshan <laijs@linux.alibaba.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Link: https://lkml.kernel.org/r/20211126101209.8613-4-jiangshanlai@gmail.com
The commit
c75890700455 ("x86/entry/64: Remove unneeded kernel CR3 switching")
removed a CR3 write in the faulting path of load_gs_index().
But the path's FENCE_SWAPGS_USER_ENTRY has no fence operation if PTI is
enabled, see spectre_v1_select_mitigation().
Rather, it depended on the serializing CR3 write of SWITCH_TO_KERNEL_CR3
and since it got removed, add a FENCE_SWAPGS_KERNEL_ENTRY call to make
sure speculation is blocked.
[ bp: Massage commit message and comment. ]
Fixes: c75890700455 ("x86/entry/64: Remove unneeded kernel CR3 switching")
Signed-off-by: Lai Jiangshan <laijs@linux.alibaba.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20211126101209.8613-3-jiangshanlai@gmail.com
Commit
18ec54fdd6d18 ("x86/speculation: Prepare entry code for Spectre v1 swapgs mitigations")
added FENCE_SWAPGS_{KERNEL|USER}_ENTRY for conditional SWAPGS. In
paranoid_entry(), it uses only FENCE_SWAPGS_KERNEL_ENTRY for both
branches. This is because the fence is required for both cases since the
CR3 write is conditional even when PTI is enabled.
But
96b2371413e8f ("x86/entry/64: Switch CR3 before SWAPGS in paranoid entry")
changed the order of SWAPGS and the CR3 write. And it missed the needed
FENCE_SWAPGS_KERNEL_ENTRY for the user gsbase case.
Add it back by changing the branches so that FENCE_SWAPGS_KERNEL_ENTRY
can cover both branches.
[ bp: Massage, fix typos, remove obsolete comment while at it. ]
Fixes: 96b2371413e8f ("x86/entry/64: Switch CR3 before SWAPGS in paranoid entry")
Signed-off-by: Lai Jiangshan <laijs@linux.alibaba.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lkml.kernel.org/r/20211126101209.8613-2-jiangshanlai@gmail.com
- Consolidate the macros for .byte ... opcode sequences
- Deduplicate register offset defines in include files
- Simplify the ia32,x32 compat handling of the related syscall tables to
get rid of #ifdeffery.
- Clear all EFLAGS which are not required for syscall handling
- Consolidate the syscall tables and switch the generation over to the
generic shell script and remove the CFLAGS tweaks which are not longer
required.
- Use 'int' type for system call numbers to match the generic code.
- Add more selftests for syscalls
-----BEGIN PGP SIGNATURE-----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=+sb9
-----END PGP SIGNATURE-----
Merge tag 'x86-entry-2021-06-29' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 entry code related updates from Thomas Gleixner:
- Consolidate the macros for .byte ... opcode sequences
- Deduplicate register offset defines in include files
- Simplify the ia32,x32 compat handling of the related syscall tables
to get rid of #ifdeffery.
- Clear all EFLAGS which are not required for syscall handling
- Consolidate the syscall tables and switch the generation over to the
generic shell script and remove the CFLAGS tweaks which are not
longer required.
- Use 'int' type for system call numbers to match the generic code.
- Add more selftests for syscalls
* tag 'x86-entry-2021-06-29' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/syscalls: Don't adjust CFLAGS for syscall tables
x86/syscalls: Remove -Wno-override-init for syscall tables
x86/uml/syscalls: Remove array index from syscall initializers
x86/syscalls: Clear 'offset' and 'prefix' in case they are set in env
x86/entry: Use int everywhere for system call numbers
x86/entry: Treat out of range and gap system calls the same
x86/entry/64: Sign-extend system calls on entry to int
selftests/x86/syscall: Add tests under ptrace to syscall_numbering_64
selftests/x86/syscall: Simplify message reporting in syscall_numbering
selftests/x86/syscall: Update and extend syscall_numbering_64
x86/syscalls: Switch to generic syscallhdr.sh
x86/syscalls: Use __NR_syscalls instead of __NR_syscall_max
x86/unistd: Define X32_NR_syscalls only for 64-bit kernel
x86/syscalls: Stop filling syscall arrays with *_sys_ni_syscall
x86/syscalls: Switch to generic syscalltbl.sh
x86/entry/x32: Rename __x32_compat_sys_* to __x64_compat_sys_*
- Micro-optimize and standardize the do_syscall_64() calling convention
- Make syscall entry flags clearing more conservative
- Clean up syscall table handling
- Clean up & standardize assembly macros, in preparation of FRED
- Misc cleanups and fixes
Signed-off-by: Ingo Molnar <mingo@kernel.org>
-----BEGIN PGP SIGNATURE-----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=mbmH
-----END PGP SIGNATURE-----
Merge tag 'x86-asm-2021-06-28' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 asm updates from Ingo Molnar:
- Micro-optimize and standardize the do_syscall_64() calling convention
- Make syscall entry flags clearing more conservative
- Clean up syscall table handling
- Clean up & standardize assembly macros, in preparation of FRED
- Misc cleanups and fixes
* tag 'x86-asm-2021-06-28' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/asm: Make <asm/asm.h> valid on cross-builds as well
x86/regs: Syscall_get_nr() returns -1 for a non-system call
x86/entry: Split PUSH_AND_CLEAR_REGS into two submacros
x86/syscall: Maximize MSR_SYSCALL_MASK
x86/syscall: Unconditionally prototype {ia32,x32}_sys_call_table[]
x86/entry: Reverse arguments to do_syscall_64()
x86/entry: Unify definitions from <asm/calling.h> and <asm/ptrace-abi.h>
x86/asm: Use _ASM_BYTES() in <asm/nops.h>
x86/asm: Add _ASM_BYTES() macro for a .byte ... opcode sequence
x86/asm: Have the __ASM_FORM macros handle commas in arguments
Split up the #VC handler code into a from-user and a from-kernel part.
This allows clean and correct state tracking, as the #VC handler needs
to enter NMI-state when raised from kernel mode and plain IRQ state when
raised from user-mode.
Fixes: 62441a1fb532 ("x86/sev-es: Correctly track IRQ states in runtime #VC handler")
Suggested-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Joerg Roedel <jroedel@suse.de>
Signed-off-by: Borislav Petkov <bp@suse.de>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20210618115409.22735-3-joro@8bytes.org
Right now, *some* code will treat e.g. 0x0000000100000001 as a system
call and some will not. Some of the code, notably in ptrace, will
treat 0x000000018000000 as a system call and some will not. Finally,
right now, e.g. 335 for x86-64 will force the exit code to be set to
-ENOSYS even if poked by ptrace, but 548 will not, because there is an
observable difference between an out of range system call and a system
call number that falls outside the range of the table.
This is visible to the user: for example, the syscall_numbering_64
test fails if run under strace, because as strace uses ptrace, it ends
up clobbering the upper half of the 64-bit system call number.
The architecture independent code all assumes that a system call is "int"
that the value -1 specifically and not just any negative value is used for
a non-system call. This is the case on x86 as well when arch-independent
code is involved. The arch-independent API is defined/documented (but not
*implemented*!) in <asm-generic/syscall.h>.
This is an ABI change, but is in fact a revert to the original x86-64
ABI. The original assembly entry code would zero-extend the system call
number;
Use sign extend to be explicit that this is treated as a signed number
(although in practice it makes no difference, of course) and to avoid
people getting the idea of "optimizing" it, as has happened on at least
two(!) separate occasions.
Do not store the extended value into regs->orig_ax, however: on x86-64, the
ABI is that the callee is responsible for extending parameters, so only
examining the lower 32 bits is fully consistent with any "int" argument to
any system call, e.g. regs->di for write(2). The full value of %rax on
entry to the kernel is thus still available.
[ tglx: Add a comment to the ASM code ]
Signed-off-by: H. Peter Anvin (Intel) <hpa@zytor.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/20210518191303.4135296-5-hpa@zytor.com
Reverse the order of arguments to do_syscall_64() so that the first
argument is the pt_regs pointer. This is not only consistent with
*all* other entry points from assembly, but it actually makes the
compiled code slightly better.
Signed-off-by: H. Peter Anvin (Intel) <hpa@zytor.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/20210510185316.3307264-3-hpa@zytor.com
-----BEGIN PGP SIGNATURE-----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=bO1i
-----END PGP SIGNATURE-----
Merge tag 'x86_cleanups_for_v5.13' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull misc x86 cleanups from Borislav Petkov:
"Trivial cleanups and fixes all over the place"
* tag 'x86_cleanups_for_v5.13' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
MAINTAINERS: Remove me from IDE/ATAPI section
x86/pat: Do not compile stubbed functions when X86_PAT is off
x86/asm: Ensure asm/proto.h can be included stand-alone
x86/platform/intel/quark: Fix incorrect kernel-doc comment syntax in files
x86/msr: Make locally used functions static
x86/cacheinfo: Remove unneeded dead-store initialization
x86/process/64: Move cpu_current_top_of_stack out of TSS
tools/turbostat: Unmark non-kernel-doc comment
x86/syscalls: Fix -Wmissing-prototypes warnings from COND_SYSCALL()
x86/fpu/math-emu: Fix function cast warning
x86/msr: Fix wr/rdmsr_safe_regs_on_cpu() prototypes
x86: Fix various typos in comments, take #2
x86: Remove unusual Unicode characters from comments
x86/kaslr: Return boolean values from a function returning bool
x86: Fix various typos in comments
x86/setup: Remove unused RESERVE_BRK_ARRAY()
stacktrace: Move documentation for arch_stack_walk_reliable() to header
x86: Remove duplicate TSC DEADLINE MSR definitions
