linux-stable.git/arch/x86/kernel/static_call.c, branch linux-rolling-stable

objtool: Remove newlines and tabs from annotation macros

2025-12-03T18:42:37+00:00

Remove newlines and tabs from the annotation macros so the invoking code
can insert them as needed to match the style of the surrounding code.

Signed-off-by: Josh Poimboeuf 
Signed-off-by: Ingo Molnar 
Cc: Linus Torvalds 
Link: https://patch.msgid.link/66305834c2eb78f082217611b756231ae9c0b555.1764694625.git.jpoimboe@kernel.org

x86_64/bug: Inline the UD1

2025-11-24T19:23:25+00:00

(Ab)use the static_call infrastructure to convert all:

  call __WARN_trap

instances into the desired:

  ud1 (%edx), %rdi

eliminating the CALL/RET, but more importantly, fixing the
fact that all WARNs will have:

  RIP: 0010:__WARN_trap+0

Basically, by making it a static_call trampoline call, objtool will
collect the callsites, and then the inline rewrite will hit the
special case and replace the code with the magic instruction.

Signed-off-by: Peter Zijlstra (Intel) 
Link: https://patch.msgid.link/20251110115758.456717741@infradead.org

Merge commit 'its-for-linus-20250509-merge' into x86/core, to resolve conflicts

2025-05-13T08:47:10+00:00

 Conflicts:
	Documentation/admin-guide/hw-vuln/index.rst
	arch/x86/include/asm/cpufeatures.h
	arch/x86/kernel/alternative.c
	arch/x86/kernel/cpu/bugs.c
	arch/x86/kernel/cpu/common.c
	drivers/base/cpu.c
	include/linux/cpu.h

Signed-off-by: Ingo Molnar

x86/its: Add support for ITS-safe return thunk

2025-05-09T20:22:05+00:00

RETs in the lower half of cacheline may be affected by ITS bug,
specifically when the RSB-underflows. Use ITS-safe return thunk for such
RETs.

RETs that are not patched:

- RET in retpoline sequence does not need to be patched, because the
  sequence itself fills an RSB before RET.
- RET in Call Depth Tracking (CDT) thunks __x86_indirect_{call|jump}_thunk
  and call_depth_return_thunk are not patched because CDT by design
  prevents RSB-underflow.
- RETs in .init section are not reachable after init.
- RETs that are explicitly marked safe with ANNOTATE_UNRET_SAFE.

Signed-off-by: Pawan Gupta 
Signed-off-by: Dave Hansen 
Reviewed-by: Josh Poimboeuf 
Reviewed-by: Alexandre Chartre

x86/alternatives: Rename 'text_poke_bp()' to 'smp_text_poke_single()'

2025-04-11T09:01:33+00:00

Signed-off-by: Ingo Molnar 
Cc: Juergen Gross 
Cc: "H . Peter Anvin" 
Cc: Linus Torvalds 
Cc: Peter Zijlstra 
Link: https://lore.kernel.org/r/20250411054105.2341982-7-mingo@kernel.org

static_call_inline: Provide trampoline address when updating sites

2025-02-26T15:39:43+00:00

In preparation of support of inline static calls on powerpc, provide
trampoline address when updating sites, so that when the destination
function is too far for a direct function call, the call site is
patched with a call to the trampoline.

Signed-off-by: Christophe Leroy 
Signed-off-by: Madhavan Srinivasan 
Link: https://patch.msgid.link/5efe0cffc38d6f69b1ec13988a99f1acff551abf.1733245362.git.christophe.leroy@csgroup.eu

x86/static-call: Remove early_boot_irqs_disabled check to fix Xen PVH dom0

2025-01-02T16:11:29+00:00

__static_call_update_early() has a check for early_boot_irqs_disabled, but
is used before early_boot_irqs_disabled is set up in start_kernel().

Xen PV has always special cased early_boot_irqs_disabled, but Xen PVH does
not and falls over the BUG when booting as dom0.

It is very suspect that early_boot_irqs_disabled starts as 0, becomes 1 for
a time, then becomes 0 again, but as this needs backporting to fix a
breakage in a security fix, dropping the BUG_ON() is the far safer option.

Fixes: 0ef8047b737d ("x86/static-call: provide a way to do very early static-call updates")
Closes: https://bugzilla.kernel.org/show_bug.cgi?id=219620
Reported-by: Alex Zenla 
Suggested-by: Peter Zijlstra 
Signed-off-by: Andrew Cooper 
Signed-off-by: Borislav Petkov (AMD) 
Reviewed-by: Juergen Gross 
Acked-by: Peter Zijlstra (Intel) 
Tested-by: Alex Zenla 
Link: https://lore.kernel.org/r/20241221211046.6475-1-andrew.cooper3@citrix.com

x86/static-call: provide a way to do very early static-call updates

2024-12-13T08:28:32+00:00

Add static_call_update_early() for updating static-call targets in
very early boot.

This will be needed for support of Xen guest type specific hypercall
functions.

This is part of XSA-466 / CVE-2024-53241.

Reported-by: Andrew Cooper 
Signed-off-by: Juergen Gross 
Co-developed-by: Peter Zijlstra 
Co-developed-by: Josh Poimboeuf

x86/bugs: Rename CONFIG_RETHUNK => CONFIG_MITIGATION_RETHUNK

2024-01-10T09:52:29+00:00

Step 10/10 of the namespace unification of CPU mitigations related Kconfig options.

[ mingo: Added one more case. ]

Suggested-by: Josh Poimboeuf 
Signed-off-by: Breno Leitao 
Signed-off-by: Ingo Molnar 
Acked-by: Josh Poimboeuf 
Cc: Linus Torvalds 
Link: https://lore.kernel.org/r/20231121160740.1249350-11-leitao@debian.org

x86/static_call: Fix __static_call_fixup()

2023-08-17T11:24:09+00:00

Christian reported spurious module load crashes after some of Song's
module memory layout patches.

Turns out that if the very last instruction on the very last page of the
module is a 'JMP __x86_return_thunk' then __static_call_fixup() will
trip a fault and die.

And while the module rework made this slightly more likely to happen,
it's always been possible.

Fixes: ee88d363d156 ("x86,static_call: Use alternative RET encoding")
Reported-by: Christian Bricart 
Signed-off-by: Peter Zijlstra (Intel) 
Acked-by: Josh Poimboeuf 
Link: https://lkml.kernel.org/r/20230816104419.GA982867@hirez.programming.kicks-ass.net