From: Marco Elver <elver(a)google.com>
kasan, powerpc: Don't rename memintrinsics if compiler adds prefixes
With appropriate compiler support [1], KASAN builds use __asan prefixed
meminstrinsics, and KASAN no longer overrides memcpy/memset/memmove.
If compiler support is detected (CC_HAS_KASAN_MEMINTRINSIC_PREFIX),
define memintrinsics normally (do not prefix '__').
On powerpc, KASAN is the only user of __mem functions, which are used to
define instrumented memintrinsics. Alias the normal versions for KASAN
to use in its implementation.
Link:
https://lore.kernel.org/all/20230224085942.1791837-1-elver@google.com/ [1]
Link:
https://lore.kernel.org/oe-kbuild-all/202302271348.U5lvmo0S-lkp@intel.com/
Reported-by: kernel test robot <lkp(a)intel.com>
Signed-off-by: Marco Elver <elver(a)google.com>
Acked-by: Michael Ellerman <mpe(a)ellerman.id.au> (powerpc)
diff --git a/arch/powerpc/include/asm/kasan.h b/arch/powerpc/include/asm/kasan.h
index blahblah..blahblah 100644
--- a/arch/powerpc/include/asm/kasan.h
+++ b/arch/powerpc/include/asm/kasan.h
@@ -2,7 +2,7 @@
#ifndef __ASM_KASAN_H
#define __ASM_KASAN_H
-#ifdef CONFIG_KASAN
+#if defined(CONFIG_KASAN) && !defined(CONFIG_CC_HAS_KASAN_MEMINTRINSIC_PREFIX)
#define _GLOBAL_KASAN(fn) _GLOBAL(__##fn)
#define _GLOBAL_TOC_KASAN(fn) _GLOBAL_TOC(__##fn)
#define EXPORT_SYMBOL_KASAN(fn) EXPORT_SYMBOL(__##fn)
diff --git a/arch/powerpc/include/asm/string.h b/arch/powerpc/include/asm/string.h
index blahblah..blahblah 100644
--- a/arch/powerpc/include/asm/string.h
+++ b/arch/powerpc/include/asm/string.h
@@ -30,11 +30,17 @@ extern int memcmp(const void *,const void *,__kernel_size_t);
extern void * memchr(const void *,int,__kernel_size_t);
void memcpy_flushcache(void *dest, const void *src, size_t size);
+#ifdef CONFIG_KASAN
+/* __mem variants are used by KASAN to implement instrumented meminstrinsics. */
+#ifdef CONFIG_CC_HAS_KASAN_MEMINTRINSIC_PREFIX
+#define __memset memset
+#define __memcpy memcpy
+#define __memmove memmove
+#else /* CONFIG_CC_HAS_KASAN_MEMINTRINSIC_PREFIX */
void *__memset(void *s, int c, __kernel_size_t count);
void *__memcpy(void *to, const void *from, __kernel_size_t n);
void *__memmove(void *to, const void *from, __kernel_size_t n);
-
-#if defined(CONFIG_KASAN) && !defined(__SANITIZE_ADDRESS__)
+#ifndef __SANITIZE_ADDRESS__
/*
* For files that are not instrumented (e.g. mm/slub.c) we
* should use not instrumented version of mem* functions.
@@ -46,8 +52,9 @@ void *__memmove(void *to, const void *from, __kernel_size_t n);
#ifndef __NO_FORTIFY
#define __NO_FORTIFY /* FORTIFY_SOURCE uses __builtin_memcpy, etc. */
#endif
-
-#endif
+#endif /* !__SANITIZE_ADDRESS__ */
+#endif /* CONFIG_CC_HAS_KASAN_MEMINTRINSIC_PREFIX */
+#endif /* CONFIG_KASAN */
#ifdef CONFIG_PPC64
#ifndef CONFIG_KASAN
diff --git a/arch/powerpc/kernel/prom_init_check.sh
b/arch/powerpc/kernel/prom_init_check.sh
index blahblah..blahblah 100644
--- a/arch/powerpc/kernel/prom_init_check.sh
+++ b/arch/powerpc/kernel/prom_init_check.sh
@@ -13,8 +13,13 @@
# If you really need to reference something from prom_init.o add
# it to the list below:
-grep "^CONFIG_KASAN=y$" ${KCONFIG_CONFIG} >/dev/null
-if [ $? -eq 0 ]
+has_renamed_memintrinsics()
+{
+ grep -q "^CONFIG_KASAN=y$" ${KCONFIG_CONFIG} && \
+ ! grep -q "^CONFIG_CC_HAS_KASAN_MEMINTRINSIC_PREFIX=y" ${KCONFIG_CONFIG}
+}
+
+if has_renamed_memintrinsics
then
MEM_FUNCS="__memcpy __memset"
else
--
https://gitlab.com/cki-project/kernel-ark/-/merge_requests/2363