Re: [PATCH v9 02/11] powerpc: prepare string/mem functions for KASAN
From: Christophe Leroy
Date: Wed Mar 06 2019 - 16:54:28 EST
Le 04/03/2019 Ã 06:26, Daniel Axtens a ÃcritÂ:
Hi Christophe,
diff --git a/arch/powerpc/include/asm/kasan.h b/arch/powerpc/include/asm/kasan.h
new file mode 100644
index 000000000000..c3161b8fc017
--- /dev/null
+++ b/arch/powerpc/include/asm/kasan.h
@@ -0,0 +1,15 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef __ASM_KASAN_H
+#define __ASM_KASAN_H
+
+#ifdef CONFIG_KASAN
+#define _GLOBAL_KASAN(fn) .weak fn ; _GLOBAL(__##fn) ; _GLOBAL(fn)
+#define _GLOBAL_TOC_KASAN(fn) .weak fn ; _GLOBAL_TOC(__##fn) ; _GLOBAL_TOC(fn)
+#define EXPORT_SYMBOL_KASAN(fn) EXPORT_SYMBOL(__##fn) ; EXPORT_SYMBOL(fn)
I'm having some trouble with this. I get warnings like this:
I don't have such problem, neither with ppc32 nor with ppc64e_defconfig.
What config are you using ?
Another (unrelated) question I have:
On the initial arm64 implementation (39d114ddc682 arm64: add KASAN
support) they made KASAN implementation depend on SPARSEMEM_VMEMMAP
(allthough they later removed that dependency with commit e17d8025f07e
arm64/mm/kasan: don't use vmemmap_populate() to initialize shadow)
So I'm wondering why on your side, KASAN depends on !SPARSEMEM_VMEMMAP
Thanks
Christophe
WARNING: EXPORT symbol "__memcpy" [vmlinux] version generation failed, symbol will not be versioned.
It seems to be related to the export line, as if I swap the exports to
do fn before __##fn I get:
WARNING: EXPORT symbol "memset" [vmlinux] version generation failed, symbol will not be versioned.
I have narrowed this down to combining 2 EXPORT_SYMBOL()s on one line.
This works - no warning:
EXPORT_SYMBOL(memset)
EXPORT_SYMBOL(__memset)
This throws a warning:
EXPORT_SYMBOL(memset) ; EXPORT_SYMBOL(__memset)
I notice in looking at the diff of preprocessed source we end up
invoking an asm macro that doesn't seem to have a full final argument, I
wonder if that's relevant...
-___EXPORT_SYMBOL __memset, __memset, ; ___EXPORT_SYMBOL memset, memset,
+___EXPORT_SYMBOL __memset, __memset,
+___EXPORT_SYMBOL memset, memset,
I also notice that nowhere else in the source do people have multiple
EXPORT_SYMBOLs on the same line, and other arches seem to just
unconditionally export both symbols on multiple lines.
I have no idea how this works for you - maybe it's affected by something 32bit.
How would you feel about this approach instead? I'm not tied to any of
the names or anything.
diff --git a/arch/powerpc/include/asm/ppc_asm.h b/arch/powerpc/include/asm/ppc_asm.h
index e0637730a8e7..7b6a91b448dd 100644
--- a/arch/powerpc/include/asm/ppc_asm.h
+++ b/arch/powerpc/include/asm/ppc_asm.h
@@ -214,6 +214,9 @@ name: \
#define DOTSYM(a) a
+#define PROVIDE_WEAK_ALIAS(strongname, weakname) \
+ .weak weakname ; .set weakname, strongname ;
+
#else
#define XGLUE(a,b) a##b
@@ -236,6 +239,10 @@ GLUE(.,name):
#define DOTSYM(a) GLUE(.,a)
+#define PROVIDE_WEAK_ALIAS(strongname, weakname) \
+ .weak weakname ; .set weakname, strongname ; \
+ .weak DOTSYM(weakname) ; .set DOTSYM(weakname), DOTSYM(strongname) ;
+
#endif
#else /* 32-bit */
@@ -251,6 +258,9 @@ GLUE(.,name):
#define _GLOBAL_TOC(name) _GLOBAL(name)
+#define PROVIDE_WEAK_ALIAS(strongname, weakname) \
+ .weak weakname ; .set weakname, strongname ;
+
#endif
/*
--- a/arch/powerpc/lib/mem_64.S
+++ b/arch/powerpc/lib/mem_64.S
@@ -33,7 +33,8 @@ EXPORT_SYMBOL(__memset32)
EXPORT_SYMBOL(__memset64)
#endif
-_GLOBAL_KASAN(memset)
+PROVIDE_WEAK_ALIAS(__memset,memset)
+_GLOBAL(__memset)
neg r0,r3
rlwimi r4,r4,8,16,23
andi. r0,r0,7 /* # bytes to be 8-byte aligned */
@@ -98,9 +99,11 @@ _GLOBAL_KASAN(memset)
10: bflr 31
stb r4,0(r6)
blr
-EXPORT_SYMBOL_KASAN(memset)
+EXPORT_SYMBOL(memset)
+EXPORT_SYMBOL(__memset)
-_GLOBAL_TOC_KASAN(memmove)
+PROVIDE_WEAK_ALIAS(__memmove,memove)
+_GLOBAL_TOC(__memmove)
cmplw 0,r3,r4
bgt backwards_memcpy
b memcpy
@@ -141,4 +144,5 @@ _GLOBAL(backwards_memcpy)
beq 2b
mtctr r7
b 1b
-EXPORT_SYMBOL_KASAN(memmove)
+EXPORT_SYMBOL(memmove)
+EXPORT_SYMBOL(__memmove)
diff --git a/arch/powerpc/lib/memcpy_64.S b/arch/powerpc/lib/memcpy_64.S
index 862b515b8868..7c1b09556cad 100644
--- a/arch/powerpc/lib/memcpy_64.S
+++ b/arch/powerpc/lib/memcpy_64.S
@@ -19,7 +19,8 @@
#endif
.align 7
-_GLOBAL_TOC_KASAN(memcpy)
+PROVIDE_WEAK_ALIAS(__memcpy,memcpy)
+_GLOBAL_TOC(__memcpy)
BEGIN_FTR_SECTION
#ifdef __LITTLE_ENDIAN__
cmpdi cr7,r5,0
@@ -230,4 +231,5 @@ END_FTR_SECTION_IFCLR(CPU_FTR_UNALIGNED_LD_STD)
4: ld r3,-STACKFRAMESIZE+STK_REG(R31)(r1) /* return dest pointer */
blr
#endif
-EXPORT_SYMBOL_KASAN(memcpy)
+EXPORT_SYMBOL(__memcpy)
+EXPORT_SYMBOL(memcpy)
Regards,
Daniel
+#else
+#define _GLOBAL_KASAN(fn) _GLOBAL(fn)
+#define _GLOBAL_TOC_KASAN(fn) _GLOBAL_TOC(fn)
+#define EXPORT_SYMBOL_KASAN(fn) EXPORT_SYMBOL(fn)
+#endif
+
+#endif
diff --git a/arch/powerpc/include/asm/string.h b/arch/powerpc/include/asm/string.h
index 1647de15a31e..9bf6dffb4090 100644
--- a/arch/powerpc/include/asm/string.h
+++ b/arch/powerpc/include/asm/string.h
@@ -4,14 +4,17 @@
#ifdef __KERNEL__
+#ifndef CONFIG_KASAN
#define __HAVE_ARCH_STRNCPY
#define __HAVE_ARCH_STRNCMP
+#define __HAVE_ARCH_MEMCHR
+#define __HAVE_ARCH_MEMCMP
+#define __HAVE_ARCH_MEMSET16
+#endif
+
#define __HAVE_ARCH_MEMSET
#define __HAVE_ARCH_MEMCPY
#define __HAVE_ARCH_MEMMOVE
-#define __HAVE_ARCH_MEMCMP
-#define __HAVE_ARCH_MEMCHR
-#define __HAVE_ARCH_MEMSET16
#define __HAVE_ARCH_MEMCPY_FLUSHCACHE
extern char * strcpy(char *,const char *);
@@ -27,7 +30,27 @@ extern int memcmp(const void *,const void *,__kernel_size_t);
extern void * memchr(const void *,int,__kernel_size_t);
extern void * memcpy_flushcache(void *,const void *,__kernel_size_t);
+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__)
+/*
+ * For files that are not instrumented (e.g. mm/slub.c) we
+ * should use not instrumented version of mem* functions.
+ */
+#define memcpy(dst, src, len) __memcpy(dst, src, len)
+#define memmove(dst, src, len) __memmove(dst, src, len)
+#define memset(s, c, n) __memset(s, c, n)
+
+#ifndef __NO_FORTIFY
+#define __NO_FORTIFY /* FORTIFY_SOURCE uses __builtin_memcpy, etc. */
+#endif
+
+#endif
+
#ifdef CONFIG_PPC64
+#ifndef CONFIG_KASAN
#define __HAVE_ARCH_MEMSET32
#define __HAVE_ARCH_MEMSET64
@@ -49,8 +72,11 @@ static inline void *memset64(uint64_t *p, uint64_t v, __kernel_size_t n)
{
return __memset64(p, v, n * 8);
}
+#endif
#else
+#ifndef CONFIG_KASAN
#define __HAVE_ARCH_STRLEN
+#endif
extern void *memset16(uint16_t *, uint16_t, __kernel_size_t);
#endif
diff --git a/arch/powerpc/kernel/prom_init_check.sh b/arch/powerpc/kernel/prom_init_check.sh
index 667df97d2595..181fd10008ef 100644
--- a/arch/powerpc/kernel/prom_init_check.sh
+++ b/arch/powerpc/kernel/prom_init_check.sh
@@ -16,8 +16,16 @@
# If you really need to reference something from prom_init.o add
# it to the list below:
+grep "^CONFIG_KASAN=y$" .config >/dev/null
+if [ $? -eq 0 ]
+then
+ MEM_FUNCS="__memcpy __memset"
+else
+ MEM_FUNCS="memcpy memset"
+fi
+
WHITELIST="add_reloc_offset __bss_start __bss_stop copy_and_flush
-_end enter_prom memcpy memset reloc_offset __secondary_hold
+_end enter_prom $MEM_FUNCS reloc_offset __secondary_hold
__secondary_hold_acknowledge __secondary_hold_spinloop __start
strcmp strcpy strlcpy strlen strncmp strstr kstrtobool logo_linux_clut224
reloc_got2 kernstart_addr memstart_addr linux_banner _stext
diff --git a/arch/powerpc/lib/Makefile b/arch/powerpc/lib/Makefile
index 79396e184bca..47a4de434c22 100644
--- a/arch/powerpc/lib/Makefile
+++ b/arch/powerpc/lib/Makefile
@@ -8,9 +8,14 @@ ccflags-$(CONFIG_PPC64) := $(NO_MINIMAL_TOC)
CFLAGS_REMOVE_code-patching.o = $(CC_FLAGS_FTRACE)
CFLAGS_REMOVE_feature-fixups.o = $(CC_FLAGS_FTRACE)
-obj-y += string.o alloc.o code-patching.o feature-fixups.o
+obj-y += alloc.o code-patching.o feature-fixups.o
-obj-$(CONFIG_PPC32) += div64.o copy_32.o crtsavres.o strlen_32.o
+ifndef CONFIG_KASAN
+obj-y += string.o memcmp_$(BITS).o
+obj-$(CONFIG_PPC32) += strlen_32.o
+endif
+
+obj-$(CONFIG_PPC32) += div64.o copy_32.o crtsavres.o
obj-$(CONFIG_FUNCTION_ERROR_INJECTION) += error-inject.o
@@ -34,7 +39,7 @@ obj64-$(CONFIG_KPROBES_SANITY_TEST) += test_emulate_step.o \
test_emulate_step_exec_instr.o
obj-y += checksum_$(BITS).o checksum_wrappers.o \
- string_$(BITS).o memcmp_$(BITS).o
+ string_$(BITS).o
obj-y += sstep.o ldstfp.o quad.o
obj64-y += quad.o
diff --git a/arch/powerpc/lib/copy_32.S b/arch/powerpc/lib/copy_32.S
index ba66846fe973..fc4fa7246200 100644
--- a/arch/powerpc/lib/copy_32.S
+++ b/arch/powerpc/lib/copy_32.S
@@ -14,6 +14,7 @@
#include <asm/ppc_asm.h>
#include <asm/export.h>
#include <asm/code-patching-asm.h>
+#include <asm/kasan.h>
#define COPY_16_BYTES \
lwz r7,4(r4); \
@@ -68,6 +69,7 @@ CACHELINE_BYTES = L1_CACHE_BYTES
LG_CACHELINE_BYTES = L1_CACHE_SHIFT
CACHELINE_MASK = (L1_CACHE_BYTES-1)
+#ifndef CONFIG_KASAN
_GLOBAL(memset16)
rlwinm. r0 ,r5, 31, 1, 31
addi r6, r3, -4
@@ -81,6 +83,7 @@ _GLOBAL(memset16)
sth r4, 4(r6)
blr
EXPORT_SYMBOL(memset16)
+#endif
/*
* Use dcbz on the complete cache lines in the destination
@@ -91,7 +94,7 @@ EXPORT_SYMBOL(memset16)
* We therefore skip the optimised bloc that uses dcbz. This jump is
* replaced by a nop once cache is active. This is done in machine_init()
*/
-_GLOBAL(memset)
+_GLOBAL_KASAN(memset)
cmplwi 0,r5,4
blt 7f
@@ -150,7 +153,7 @@ _GLOBAL(memset)
9: stbu r4,1(r6)
bdnz 9b
blr
-EXPORT_SYMBOL(memset)
+EXPORT_SYMBOL_KASAN(memset)
/*
* This version uses dcbz on the complete cache lines in the
@@ -163,12 +166,12 @@ EXPORT_SYMBOL(memset)
* We therefore jump to generic_memcpy which doesn't use dcbz. This jump is
* replaced by a nop once cache is active. This is done in machine_init()
*/
-_GLOBAL(memmove)
+_GLOBAL_KASAN(memmove)
cmplw 0,r3,r4
bgt backwards_memcpy
/* fall through */
-_GLOBAL(memcpy)
+_GLOBAL_KASAN(memcpy)
1: b generic_memcpy
patch_site 1b, patch__memcpy_nocache
@@ -242,8 +245,8 @@ _GLOBAL(memcpy)
stbu r0,1(r6)
bdnz 40b
65: blr
-EXPORT_SYMBOL(memcpy)
-EXPORT_SYMBOL(memmove)
+EXPORT_SYMBOL_KASAN(memcpy)
+EXPORT_SYMBOL_KASAN(memmove)
generic_memcpy:
srwi. r7,r5,3
diff --git a/arch/powerpc/lib/mem_64.S b/arch/powerpc/lib/mem_64.S
index 3c3be02f33b7..7cd6cf6822a2 100644
--- a/arch/powerpc/lib/mem_64.S
+++ b/arch/powerpc/lib/mem_64.S
@@ -12,7 +12,9 @@
#include <asm/errno.h>
#include <asm/ppc_asm.h>
#include <asm/export.h>
+#include <asm/kasan.h>
+#ifndef CONFIG_KASAN
_GLOBAL(__memset16)
rlwimi r4,r4,16,0,15
/* fall through */
@@ -29,8 +31,9 @@ _GLOBAL(__memset64)
EXPORT_SYMBOL(__memset16)
EXPORT_SYMBOL(__memset32)
EXPORT_SYMBOL(__memset64)
+#endif
-_GLOBAL(memset)
+_GLOBAL_KASAN(memset)
neg r0,r3
rlwimi r4,r4,8,16,23
andi. r0,r0,7 /* # bytes to be 8-byte aligned */
@@ -95,9 +98,9 @@ _GLOBAL(memset)
10: bflr 31
stb r4,0(r6)
blr
-EXPORT_SYMBOL(memset)
+EXPORT_SYMBOL_KASAN(memset)
-_GLOBAL_TOC(memmove)
+_GLOBAL_TOC_KASAN(memmove)
cmplw 0,r3,r4
bgt backwards_memcpy
b memcpy
@@ -138,4 +141,4 @@ _GLOBAL(backwards_memcpy)
beq 2b
mtctr r7
b 1b
-EXPORT_SYMBOL(memmove)
+EXPORT_SYMBOL_KASAN(memmove)
diff --git a/arch/powerpc/lib/memcpy_64.S b/arch/powerpc/lib/memcpy_64.S
index 273ea67e60a1..862b515b8868 100644
--- a/arch/powerpc/lib/memcpy_64.S
+++ b/arch/powerpc/lib/memcpy_64.S
@@ -11,6 +11,7 @@
#include <asm/export.h>
#include <asm/asm-compat.h>
#include <asm/feature-fixups.h>
+#include <asm/kasan.h>
#ifndef SELFTEST_CASE
/* For big-endian, 0 == most CPUs, 1 == POWER6, 2 == Cell */
@@ -18,7 +19,7 @@
#endif
.align 7
-_GLOBAL_TOC(memcpy)
+_GLOBAL_TOC_KASAN(memcpy)
BEGIN_FTR_SECTION
#ifdef __LITTLE_ENDIAN__
cmpdi cr7,r5,0
@@ -229,4 +230,4 @@ END_FTR_SECTION_IFCLR(CPU_FTR_UNALIGNED_LD_STD)
4: ld r3,-STACKFRAMESIZE+STK_REG(R31)(r1) /* return dest pointer */
blr
#endif
-EXPORT_SYMBOL(memcpy)
+EXPORT_SYMBOL_KASAN(memcpy)
--
2.13.3