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From: Christophe Leroy <christophe.leroy@csgroup.eu>
To: Nicholas Miehlbradt <nicholas@linux.ibm.com>,
	"glider@google.com" <glider@google.com>,
	"elver@google.com" <elver@google.com>,
	"dvyukov@google.com" <dvyukov@google.com>,
	"akpm@linux-foundation.org" <akpm@linux-foundation.org>,
	"mpe@ellerman.id.au" <mpe@ellerman.id.au>,
	"npiggin@gmail.com" <npiggin@gmail.com>
Cc: "linux-mm@kvack.org" <linux-mm@kvack.org>,
	"linuxppc-dev@lists.ozlabs.org" <linuxppc-dev@lists.ozlabs.org>,
	"iii@linux.ibm.com" <iii@linux.ibm.com>,
	"kasan-dev@googlegroups.com" <kasan-dev@googlegroups.com>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 12/13] powerpc/string: Add KMSAN support
Date: Thu, 14 Dec 2023 09:25:44 +0000	[thread overview]
Message-ID: <2f35548a-bdbd-4c37-8f60-cebeb381a7af@csgroup.eu> (raw)
In-Reply-To: <20231214055539.9420-13-nicholas@linux.ibm.com>



Le 14/12/2023 à 06:55, Nicholas Miehlbradt a écrit :
> 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@linux.ibm.com>
> ---
>   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);
> +

The same is done for KASAN, can't you reuse it ?

> +#ifdef __SANITIZE_MEMORY__
> +#include <linux/kmsan_string.h>
> +#define memset __msan_memset
> +#define memcpy __msan_memcpy
> +#define memmove __msan_memmove
> +#endif

Will that work as you wish ?
What about the calls to memset() or memcpy() emited directly by GCC ?

> +#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)

  reply	other threads:[~2023-12-14  9:26 UTC|newest]

Thread overview: 30+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-12-14  5:55 [PATCH 00/13] kmsan: Enable on powerpc Nicholas Miehlbradt
2023-12-14  5:55 ` [PATCH 01/13] kmsan: Export kmsan_handle_dma Nicholas Miehlbradt
2024-02-19 19:37   ` Christophe Leroy
2023-12-14  5:55 ` [PATCH 02/13] hvc: Fix use of uninitialized array in udbg_hvc_putc Nicholas Miehlbradt
2023-12-14  8:36   ` Christophe Leroy
2023-12-21 12:09     ` Michael Ellerman
2023-12-14  5:55 ` [PATCH 03/13] powerpc: Disable KMSAN santitization for prom_init, vdso and purgatory Nicholas Miehlbradt
2023-12-14  5:55 ` [PATCH 04/13] powerpc: Disable CONFIG_DCACHE_WORD_ACCESS when KMSAN is enabled Nicholas Miehlbradt
2023-12-14  8:42   ` Christophe Leroy
2023-12-14  5:55 ` [PATCH 05/13] powerpc: Unpoison buffers populated by hcalls Nicholas Miehlbradt
2023-12-14  5:55 ` [PATCH 06/13] powerpc/pseries/nvram: Unpoison buffer populated by rtas_call Nicholas Miehlbradt
2023-12-14  5:55 ` [PATCH 07/13] powerpc/kprobes: Unpoison instruction in kprobe struct Nicholas Miehlbradt
2023-12-15  7:51   ` Naveen N Rao
2023-12-14  5:55 ` [PATCH 08/13] powerpc: Unpoison pt_regs Nicholas Miehlbradt
2023-12-14  5:55 ` [PATCH 09/13] powerpc: Disable KMSAN checks on functions which walk the stack Nicholas Miehlbradt
2023-12-14  9:00   ` Christophe Leroy
2024-01-10  4:16     ` Nicholas Miehlbradt
2023-12-15  9:02   ` Aneesh Kumar K.V
2023-12-14  5:55 ` [PATCH 10/13] powerpc: Define KMSAN metadata address ranges for vmalloc and ioremap Nicholas Miehlbradt
2023-12-14  9:17   ` Christophe Leroy
2024-01-10  3:54     ` Nicholas Miehlbradt
2023-12-15  9:27   ` Aneesh Kumar K.V
2023-12-14  5:55 ` [PATCH 11/13] powerpc: Implement architecture specific KMSAN interface Nicholas Miehlbradt
2023-12-14  9:20   ` Christophe Leroy
2023-12-14  5:55 ` [PATCH 12/13] powerpc/string: Add KMSAN support Nicholas Miehlbradt
2023-12-14  9:25   ` Christophe Leroy [this message]
2024-01-10  4:09     ` Nicholas Miehlbradt
2023-12-14  5:55 ` [PATCH 13/13] powerpc: Enable KMSAN on powerpc Nicholas Miehlbradt
2023-12-14  9:27   ` Christophe Leroy
2024-02-20  6:39 ` [PATCH 00/13] kmsan: Enable " Christophe Leroy

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