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x86/locking: Use ALT_OUTPUT_SP() for percpu_{,try_}cmpxchg{64,128}_op()

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percpu_{,try_}cmpxchg{64,128}() macros use CALL instruction inside
asm statement in one of their alternatives. Use ALT_OUTPUT_SP()
macro to add required dependence on %esp register.

ALT_OUTPUT_SP() implements the above dependence by adding
ASM_CALL_CONSTRAINT to its arguments. This constraint should be used
for any inline asm which has a CALL instruction, otherwise the
compiler may schedule the asm before the frame pointer gets set up
by the containing function, causing objtool to print a "call without
frame pointer save/setup" warning.

Signed-off-by: Uros Bizjak <ubizjak@gmail.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: https://lore.kernel.org/r/20250214150929.5780-1-ubizjak@gmail.com
This commit is contained in:
Uros Bizjak
2025-02-14 16:07:46 +01:00
committed by Ingo Molnar
parent 0ad2507d5d
commit 4087e16b03
1 changed files with 14 additions and 14 deletions
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28
arch/x86/include/asm/percpu.h
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@@ -350,9 +350,9 @@ do { \
\
asm qual (ALTERNATIVE("call this_cpu_cmpxchg8b_emu", \
"cmpxchg8b " __percpu_arg([var]), X86_FEATURE_CX8) \
: [var] "+m" (__my_cpu_var(_var)), \
"+a" (old__.low), \
"+d" (old__.high) \
: ALT_OUTPUT_SP([var] "+m" (__my_cpu_var(_var)), \
"+a" (old__.low), \
"+d" (old__.high)) \
: "b" (new__.low), \
"c" (new__.high), \
"S" (&(_var)) \
@@ -381,10 +381,10 @@ do { \
asm qual (ALTERNATIVE("call this_cpu_cmpxchg8b_emu", \
"cmpxchg8b " __percpu_arg([var]), X86_FEATURE_CX8) \
CC_SET(z) \
: CC_OUT(z) (success), \
[var] "+m" (__my_cpu_var(_var)), \
"+a" (old__.low), \
"+d" (old__.high) \
: ALT_OUTPUT_SP(CC_OUT(z) (success), \
[var] "+m" (__my_cpu_var(_var)), \
"+a" (old__.low), \
"+d" (old__.high)) \
: "b" (new__.low), \
"c" (new__.high), \
"S" (&(_var)) \
@@ -421,9 +421,9 @@ do { \
\
asm qual (ALTERNATIVE("call this_cpu_cmpxchg16b_emu", \
"cmpxchg16b " __percpu_arg([var]), X86_FEATURE_CX16) \
: [var] "+m" (__my_cpu_var(_var)), \
"+a" (old__.low), \
"+d" (old__.high) \
: ALT_OUTPUT_SP([var] "+m" (__my_cpu_var(_var)), \
"+a" (old__.low), \
"+d" (old__.high)) \
: "b" (new__.low), \
"c" (new__.high), \
"S" (&(_var)) \
@@ -452,10 +452,10 @@ do { \
asm qual (ALTERNATIVE("call this_cpu_cmpxchg16b_emu", \
"cmpxchg16b " __percpu_arg([var]), X86_FEATURE_CX16) \
CC_SET(z) \
: CC_OUT(z) (success), \
[var] "+m" (__my_cpu_var(_var)), \
"+a" (old__.low), \
"+d" (old__.high) \
: ALT_OUTPUT_SP(CC_OUT(z) (success), \
[var] "+m" (__my_cpu_var(_var)), \
"+a" (old__.low), \
"+d" (old__.high)) \
: "b" (new__.low), \
"c" (new__.high), \
"S" (&(_var)) \