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: Jeff Xie <xiehuan09@gmail.com>
Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>

diff --git a/arch/loongarch/include/asm/asm.h b/arch/loongarch/include/asm/asm.h
index 40eea6aa469e17c0ca5847da98046171cb590762..f591b3245def69d3deff2895e6c2d9f064225cb9 100644 (file)
--- a/arch/loongarch/include/asm/asm.h
+++ b/arch/loongarch/include/asm/asm.h
@@ -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 */

diff --git a/arch/loongarch/kernel/entry.S b/arch/loongarch/kernel/entry.S
index f14ab6a0e0b054559eaed0f96be4683c8ff69aa0..d737e3cf42d3fd8ca882e08113d58d2887db32c1 100644 (file)
--- a/arch/loongarch/kernel/entry.S
+++ b/arch/loongarch/kernel/entry.S
@@ -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

diff --git a/arch/loongarch/lib/memcpy.S b/arch/loongarch/lib/memcpy.S
index 7c07d595ee89aca1428431b18727f33332576b06..3b7e1dec71094d4eadb829b65a433a7e6e7fcdca 100644 (file)
--- a/arch/loongarch/lib/memcpy.S
+++ b/arch/loongarch/lib/memcpy.S
@@ -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)

diff --git a/arch/loongarch/lib/memmove.S b/arch/loongarch/lib/memmove.S
index 6ffdb46da78fdfee56ce06f73fb16e250d61e663..b796c3d6da05258aad1e40f9051dc81c937f4b17 100644 (file)
--- a/arch/loongarch/lib/memmove.S
+++ b/arch/loongarch/lib/memmove.S
@@ -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)

diff --git a/arch/loongarch/lib/memset.S b/arch/loongarch/lib/memset.S
index e7cb4ea3747d7ce045ad51406604fb9035da991f..a9eb732ab2adb9e132592f998717c49be542423e 100644 (file)
--- a/arch/loongarch/lib/memset.S
+++ b/arch/loongarch/lib/memset.S
@@ -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)