[PATCH 12/13] powerpc/string: Add KMSAN support
From: Nicholas Miehlbradt
Date: Thu Dec 14 2023 - 00:57:08 EST
KMSAN expects functions __mem{set,cpy,move} so add aliases pointing to
the respective functions.
Disable use of architecture specific memset{16,32,64} to ensure that
metadata is correctly updated and strn{cpy,cmp} and mem{chr,cmp} which
are implemented in assembly and therefore cannot be instrumented to
propagate/check metadata.
Alias calls to mem{set,cpy,move} to __msan_mem{set,cpy,move} in
instrumented code to correctly propagate metadata.
Signed-off-by: Nicholas Miehlbradt <nicholas@xxxxxxxxxxxxx>
---
arch/powerpc/include/asm/kmsan.h | 7 +++++++
arch/powerpc/include/asm/string.h | 18 ++++++++++++++++--
arch/powerpc/lib/Makefile | 2 ++
arch/powerpc/lib/mem_64.S | 5 ++++-
arch/powerpc/lib/memcpy_64.S | 2 ++
.../selftests/powerpc/copyloops/asm/kmsan.h | 0
.../selftests/powerpc/copyloops/linux/export.h | 1 +
7 files changed, 32 insertions(+), 3 deletions(-)
create mode 100644 tools/testing/selftests/powerpc/copyloops/asm/kmsan.h
diff --git a/arch/powerpc/include/asm/kmsan.h b/arch/powerpc/include/asm/kmsan.h
index bc84f6ff2ee9..fc59dc24e170 100644
--- a/arch/powerpc/include/asm/kmsan.h
+++ b/arch/powerpc/include/asm/kmsan.h
@@ -7,6 +7,13 @@
#ifndef _ASM_POWERPC_KMSAN_H
#define _ASM_POWERPC_KMSAN_H
+#ifdef CONFIG_KMSAN
+#define EXPORT_SYMBOL_KMSAN(fn) SYM_FUNC_ALIAS(__##fn, fn) \
+ EXPORT_SYMBOL(__##fn)
+#else
+#define EXPORT_SYMBOL_KMSAN(fn)
+#endif
+
#ifndef __ASSEMBLY__
#ifndef MODULE
diff --git a/arch/powerpc/include/asm/string.h b/arch/powerpc/include/asm/string.h
index 60ba22770f51..412626ce619b 100644
--- a/arch/powerpc/include/asm/string.h
+++ b/arch/powerpc/include/asm/string.h
@@ -4,7 +4,7 @@
#ifdef __KERNEL__
-#ifndef CONFIG_KASAN
+#if !defined(CONFIG_KASAN) && !defined(CONFIG_KMSAN)
#define __HAVE_ARCH_STRNCPY
#define __HAVE_ARCH_STRNCMP
#define __HAVE_ARCH_MEMCHR
@@ -56,8 +56,22 @@ void *__memmove(void *to, const void *from, __kernel_size_t n);
#endif /* CONFIG_CC_HAS_KASAN_MEMINTRINSIC_PREFIX */
#endif /* CONFIG_KASAN */
+#ifdef CONFIG_KMSAN
+
+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);
+
+#ifdef __SANITIZE_MEMORY__
+#include <linux/kmsan_string.h>
+#define memset __msan_memset
+#define memcpy __msan_memcpy
+#define memmove __msan_memmove
+#endif
+#endif /* CONFIG_KMSAN */
+
#ifdef CONFIG_PPC64
-#ifndef CONFIG_KASAN
+#if !defined(CONFIG_KASAN) && !defined(CONFIG_KMSAN)
#define __HAVE_ARCH_MEMSET32
#define __HAVE_ARCH_MEMSET64
diff --git a/arch/powerpc/lib/Makefile b/arch/powerpc/lib/Makefile
index 51ad0397c17a..fc3ea3eebbd6 100644
--- a/arch/powerpc/lib/Makefile
+++ b/arch/powerpc/lib/Makefile
@@ -32,9 +32,11 @@ obj-y += code-patching.o feature-fixups.o pmem.o
obj-$(CONFIG_CODE_PATCHING_SELFTEST) += test-code-patching.o
ifndef CONFIG_KASAN
+ifndef CONFIG_KMSAN
obj-y += string.o memcmp_$(BITS).o
obj-$(CONFIG_PPC32) += strlen_32.o
endif
+endif
obj-$(CONFIG_PPC32) += div64.o copy_32.o crtsavres.o
diff --git a/arch/powerpc/lib/mem_64.S b/arch/powerpc/lib/mem_64.S
index 6fd06cd20faa..a55f2fac49b3 100644
--- a/arch/powerpc/lib/mem_64.S
+++ b/arch/powerpc/lib/mem_64.S
@@ -9,8 +9,9 @@
#include <asm/errno.h>
#include <asm/ppc_asm.h>
#include <asm/kasan.h>
+#include <asm/kmsan.h>
-#ifndef CONFIG_KASAN
+#if !defined(CONFIG_KASAN) && !defined(CONFIG_KMSAN)
_GLOBAL(__memset16)
rlwimi r4,r4,16,0,15
/* fall through */
@@ -96,6 +97,7 @@ _GLOBAL_KASAN(memset)
blr
EXPORT_SYMBOL(memset)
EXPORT_SYMBOL_KASAN(memset)
+EXPORT_SYMBOL_KMSAN(memset)
_GLOBAL_TOC_KASAN(memmove)
cmplw 0,r3,r4
@@ -140,3 +142,4 @@ _GLOBAL(backwards_memcpy)
b 1b
EXPORT_SYMBOL(memmove)
EXPORT_SYMBOL_KASAN(memmove)
+EXPORT_SYMBOL_KMSAN(memmove)
diff --git a/arch/powerpc/lib/memcpy_64.S b/arch/powerpc/lib/memcpy_64.S
index b5a67e20143f..1657861618cc 100644
--- a/arch/powerpc/lib/memcpy_64.S
+++ b/arch/powerpc/lib/memcpy_64.S
@@ -8,6 +8,7 @@
#include <asm/asm-compat.h>
#include <asm/feature-fixups.h>
#include <asm/kasan.h>
+#include <asm/kmsan.h>
#ifndef SELFTEST_CASE
/* For big-endian, 0 == most CPUs, 1 == POWER6, 2 == Cell */
@@ -228,3 +229,4 @@ END_FTR_SECTION_IFCLR(CPU_FTR_UNALIGNED_LD_STD)
#endif
EXPORT_SYMBOL(memcpy)
EXPORT_SYMBOL_KASAN(memcpy)
+EXPORT_SYMBOL_KMSAN(memcpy)
diff --git a/tools/testing/selftests/powerpc/copyloops/asm/kmsan.h b/tools/testing/selftests/powerpc/copyloops/asm/kmsan.h
new file mode 100644
index 000000000000..e69de29bb2d1
diff --git a/tools/testing/selftests/powerpc/copyloops/linux/export.h b/tools/testing/selftests/powerpc/copyloops/linux/export.h
index e6b80d5fbd14..6379624bbf9b 100644
--- a/tools/testing/selftests/powerpc/copyloops/linux/export.h
+++ b/tools/testing/selftests/powerpc/copyloops/linux/export.h
@@ -2,3 +2,4 @@
#define EXPORT_SYMBOL(x)
#define EXPORT_SYMBOL_GPL(x)
#define EXPORT_SYMBOL_KASAN(x)
+#define EXPORT_SYMBOL_KMSAN(x)
--
2.40.1