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Message-ID: <c69636a6-1f43-78e6-ff88-a3e4f3a35132@c-s.fr>
Date: Wed, 6 Mar 2019 22:54:22 +0100
From: Christophe Leroy <christophe.leroy@....fr>
To: Daniel Axtens <dja@...ens.net>,
Benjamin Herrenschmidt <benh@...nel.crashing.org>,
Paul Mackerras <paulus@...ba.org>,
Michael Ellerman <mpe@...erman.id.au>,
Nicholas Piggin <npiggin@...il.com>,
"Aneesh Kumar K.V" <aneesh.kumar@...ux.ibm.com>,
Andrey Ryabinin <aryabinin@...tuozzo.com>,
Alexander Potapenko <glider@...gle.com>,
Dmitry Vyukov <dvyukov@...gle.com>
Cc: linux-kernel@...r.kernel.org, linuxppc-dev@...ts.ozlabs.org,
kasan-dev@...glegroups.com, linux-mm@...ck.org
Subject: Re: [PATCH v9 02/11] powerpc: prepare string/mem functions for KASAN
Le 04/03/2019 à 06:26, Daniel Axtens a écrit :
> 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
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