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

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

diff --git a/arch/x86/include/asm/percpu.h b/arch/x86/include/asm/percpu.h
index e525cd85f999fdc53d7686bcbfb54975d5f86584..0ab991fba7de38c6c67fe5b7b027336c5f2ed449 100644 (file)
--- a/arch/x86/include/asm/percpu.h
+++ b/arch/x86/include/asm/percpu.h
@@ -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))                                       \