x86/asm: Add unwind hint annotations to sync_core()

This enables objtool to grok the iret in the middle of a C function.

Signed-off-by: Josh Poimboeuf <[email protected]>
Cc: Andy Lutomirski <[email protected]>
Cc: Borislav Petkov <[email protected]>
Cc: Brian Gerst <[email protected]>
Cc: Denys Vlasenko <[email protected]>
Cc: H. Peter Anvin <[email protected]>
Cc: Jiri Slaby <[email protected]>
Cc: Linus Torvalds <[email protected]>
Cc: Mike Galbraith <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Cc: [email protected]
Link: http://lkml.kernel.org/r/b057be26193c11d2ed3337b2107bc7adcba42c99.1499786555.git.jpoimboe@redhat.com
Signed-off-by: Ingo Molnar <[email protected]>

diff --git a/arch/x86/include/asm/processor.h b/arch/x86/include/asm/processor.h
index 6a79547e8ee01e06a84cc948f0d9a61002cdda82..b27dc9b4a1480f81abadb0ac65dcbdf521577890 100644 (file)
--- a/arch/x86/include/asm/processor.h
+++ b/arch/x86/include/asm/processor.h
@@ -22,6 +22,7 @@ struct vm86;
 #include <asm/nops.h>
 #include <asm/special_insns.h>
 #include <asm/fpu/types.h>
+#include <asm/unwind_hints.h>
 
 #include <linux/personality.h>
 #include <linux/cache.h>
@@ -684,6 +685,7 @@ static inline void sync_core(void)
        unsigned int tmp;
 
        asm volatile (
+               UNWIND_HINT_SAVE
                "mov %%ss, %0\n\t"
                "pushq %q0\n\t"
                "pushq %%rsp\n\t"
@@ -693,6 +695,7 @@ static inline void sync_core(void)
                "pushq %q0\n\t"
                "pushq $1f\n\t"
                "iretq\n\t"
+               UNWIND_HINT_RESTORE
                "1:"
                : "=&r" (tmp), "+r" (__sp) : : "cc", "memory");
 #endif