The patch titled
Subject: kasan, powerpc: don't rename memintrinsics if compiler adds prefixes
has been added to the -mm mm-hotfixes-unstable branch. Its filename is
kasan-treat-meminstrinsic-as-builtins-in-uninstrumented-files-fix.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/kasan-treat-meminstrinsic-as-builtins-in-uninstrumented-files-fix.patch
This patch will later appear in the mm-hotfixes-unstable branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
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------------------------------------------------------
From: Marco Elver <elver@xxxxxxxxxx>
Subject: kasan, powerpc: don't rename memintrinsics if compiler adds prefixes
Date: Mon, 27 Feb 2023 10:47:27 +0100
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@xxxxxxxxxx/ [1]
Link: https://lkml.kernel.org/r/20230227094726.3833247-1-elver@xxxxxxxxxx
Signed-off-by: Marco Elver <elver@xxxxxxxxxx>
Reported-by: kernel test robot <lkp@xxxxxxxxx>
Link: https://lore.kernel.org/oe-kbuild-all/202302271348.U5lvmo0S-lkp@xxxxxxxxx/
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
--- a/arch/powerpc/include/asm/kasan.h~kasan-treat-meminstrinsic-as-builtins-in-uninstrumented-files-fix
+++ a/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)
--- a/arch/powerpc/include/asm/string.h~kasan-treat-meminstrinsic-as-builtins-in-uninstrumented-files-fix
+++ a/arch/powerpc/include/asm/string.h
@@ -30,11 +30,17 @@ extern int memcmp(const void *,const voi
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 *fr
#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
--- a/arch/powerpc/kernel/prom_init_check.sh~kasan-treat-meminstrinsic-as-builtins-in-uninstrumented-files-fix
+++ a/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
_
Patches currently in -mm which might be from elver@xxxxxxxxxx are
kasan-emit-different-calls-for-instrumentable-memintrinsics.patch
kasan-treat-meminstrinsic-as-builtins-in-uninstrumented-files.patch
kasan-treat-meminstrinsic-as-builtins-in-uninstrumented-files-fix.patch
kasan-test-fix-test-for-new-meminstrinsic-instrumentation.patch
kasan-x86-dont-rename-memintrinsics-in-uninstrumented-files.patch
