Commit fcf77d01 authored by Tiezhu Yang's avatar Tiezhu Yang Committed by Huacai Chen
Browse files

LoongArch: Mark some assembler symbols as non-kprobe-able 

Some assembler symbols are not kprobe safe, such as handle_syscall (used
as syscall exception handler), *memset*/*memcpy*/*memmove* (may cause
recursive exceptions), they can not be instrumented, just blacklist them
for kprobing.

Here is a related problem and discussion:
Link: https://lore.kernel.org/lkml/20230114143859.7ccc45c1c5d9ce302113ab0a@kernel.org/



Tested-by: default avatarJeff Xie <xiehuan09@gmail.com>
Signed-off-by: default avatarTiezhu Yang <yangtiezhu@loongson.cn>
Signed-off-by: default avatarHuacai Chen <chenhuacai@loongson.cn>
parent 09e679c2

arch/loongarch/include/asm/asm.h

+10 −0
Original line number Diff line number Diff line
@@ -188,4 +188,14 @@ 
#define PTRLOG		3

#endif



/* Annotate a function as being unsuitable for kprobes. */

#ifdef CONFIG_KPROBES

#define _ASM_NOKPROBE(name)				\

	.pushsection "_kprobe_blacklist", "aw";		\

	.quad	name;					\

	.popsection

#else

#define _ASM_NOKPROBE(name)

#endif



#endif /* __ASM_ASM_H */

arch/loongarch/kernel/entry.S

+1 −0
Original line number Diff line number Diff line
@@ -67,6 +67,7 @@ SYM_FUNC_START(handle_syscall) 


	RESTORE_ALL_AND_RET

SYM_FUNC_END(handle_syscall)

_ASM_NOKPROBE(handle_syscall)



SYM_CODE_START(ret_from_fork)

	bl		schedule_tail		# a0 = struct task_struct *prev

arch/loongarch/lib/memcpy.S

+3 −0
Original line number Diff line number Diff line
@@ -17,6 +17,7 @@ SYM_FUNC_START(memcpy) 
	ALTERNATIVE	"b __memcpy_generic", \

			"b __memcpy_fast", CPU_FEATURE_UAL

SYM_FUNC_END(memcpy)

_ASM_NOKPROBE(memcpy)



EXPORT_SYMBOL(memcpy)
@@ -41,6 +42,7 @@ SYM_FUNC_START(__memcpy_generic) 
2:	move	a0, a3

	jr	ra

SYM_FUNC_END(__memcpy_generic)

_ASM_NOKPROBE(__memcpy_generic)



/*

 * void *__memcpy_fast(void *dst, const void *src, size_t n)
@@ -93,3 +95,4 @@ SYM_FUNC_START(__memcpy_fast) 
3:	move	a0, a3

	jr	ra

SYM_FUNC_END(__memcpy_fast)

_ASM_NOKPROBE(__memcpy_fast)

arch/loongarch/lib/memmove.S

+4 −0
Original line number Diff line number Diff line
@@ -29,6 +29,7 @@ SYM_FUNC_START(memmove) 
	b	rmemcpy

4:	b	__rmemcpy_generic

SYM_FUNC_END(memmove)

_ASM_NOKPROBE(memmove)



EXPORT_SYMBOL(memmove)
@@ -39,6 +40,7 @@ SYM_FUNC_START(rmemcpy) 
	ALTERNATIVE	"b __rmemcpy_generic", \

			"b __rmemcpy_fast", CPU_FEATURE_UAL

SYM_FUNC_END(rmemcpy)

_ASM_NOKPROBE(rmemcpy)



/*

 * void *__rmemcpy_generic(void *dst, const void *src, size_t n)
@@ -64,6 +66,7 @@ SYM_FUNC_START(__rmemcpy_generic) 
2:	move	a0, a3

	jr	ra

SYM_FUNC_END(__rmemcpy_generic)

_ASM_NOKPROBE(__rmemcpy_generic)



/*

 * void *__rmemcpy_fast(void *dst, const void *src, size_t n)
@@ -119,3 +122,4 @@ SYM_FUNC_START(__rmemcpy_fast) 
3:	move	a0, a3

	jr	ra

SYM_FUNC_END(__rmemcpy_fast)

_ASM_NOKPROBE(__rmemcpy_fast)

arch/loongarch/lib/memset.S

+3 −0
Original line number Diff line number Diff line
@@ -23,6 +23,7 @@ SYM_FUNC_START(memset) 
	ALTERNATIVE	"b __memset_generic", \

			"b __memset_fast", CPU_FEATURE_UAL

SYM_FUNC_END(memset)

_ASM_NOKPROBE(memset)



EXPORT_SYMBOL(memset)
@@ -45,6 +46,7 @@ SYM_FUNC_START(__memset_generic) 
2:	move	a0, a3

	jr	ra

SYM_FUNC_END(__memset_generic)

_ASM_NOKPROBE(__memset_generic)



/*

 * void *__memset_fast(void *s, int c, size_t n)
@@ -89,3 +91,4 @@ SYM_FUNC_START(__memset_fast) 
3:	move	a0, a3

	jr	ra

SYM_FUNC_END(__memset_fast)

_ASM_NOKPROBE(__memset_fast)