Commit eb4a3f7d authored by Josh Poimboeuf's avatar Josh Poimboeuf Committed by Steven Rostedt (VMware)
Browse files

x86/kprobes: Add UNWIND_HINT_FUNC on kretprobe_trampoline() 

Add UNWIND_HINT_FUNC on __kretprobe_trampoline() code so that ORC
information is generated on the __kretprobe_trampoline() correctly.
Also, this uses STACK_FRAME_NON_STANDARD_FP(), CONFIG_FRAME_POINTER-
-specific version of STACK_FRAME_NON_STANDARD().

Link: https://lkml.kernel.org/r/163163049242.489837.11970969750993364293.stgit@devnote2



Signed-off-by: default avatarJosh Poimboeuf <jpoimboe@redhat.com>
Signed-off-by: default avatarMasami Hiramatsu <mhiramat@kernel.org>
Tested-by: default avatarAndrii Nakryiko <andrii@kernel.org>
Signed-off-by: default avatarSteven Rostedt (VMware) <rostedt@goodmis.org>
parent 5b284b19

arch/x86/include/asm/unwind_hints.h

+5 −0
Original line number Diff line number Diff line
@@ -52,6 +52,11 @@ 
	UNWIND_HINT sp_reg=ORC_REG_SP sp_offset=8 type=UNWIND_HINT_TYPE_FUNC

.endm



#else



#define UNWIND_HINT_FUNC \

	UNWIND_HINT(ORC_REG_SP, 8, UNWIND_HINT_TYPE_FUNC, 0)



#endif /* __ASSEMBLY__ */



#endif /* _ASM_X86_UNWIND_HINTS_H */

arch/x86/kernel/kprobes/core.c

+11 −2
Original line number Diff line number Diff line
@@ -1025,6 +1025,7 @@ asm( 
	/* We don't bother saving the ss register */

#ifdef CONFIG_X86_64

	"	pushq %rsp\n"

	UNWIND_HINT_FUNC

	"	pushfq\n"

	SAVE_REGS_STRING

	"	movq %rsp, %rdi\n"
@@ -1035,6 +1036,7 @@ asm( 
	"	popfq\n"

#else

	"	pushl %esp\n"

	UNWIND_HINT_FUNC

	"	pushfl\n"

	SAVE_REGS_STRING

	"	movl %esp, %eax\n"
@@ -1048,8 +1050,15 @@ asm( 
	".size __kretprobe_trampoline, .-__kretprobe_trampoline\n"

);

NOKPROBE_SYMBOL(__kretprobe_trampoline);

STACK_FRAME_NON_STANDARD(__kretprobe_trampoline);



/*

 * __kretprobe_trampoline() skips updating frame pointer. The frame pointer

 * saved in trampoline_handler() points to the real caller function's

 * frame pointer. Thus the __kretprobe_trampoline() doesn't have a

 * standard stack frame with CONFIG_FRAME_POINTER=y.

 * Let's mark it non-standard function. Anyway, FP unwinder can correctly

 * unwind without the hint.

 */

STACK_FRAME_NON_STANDARD_FP(__kretprobe_trampoline);



/*

 * Called from __kretprobe_trampoline