From 10f4c9b9a33b7df000f74fa0d896351fb1a61e6a Mon Sep 17 00:00:00 2001 From: Vincent Whitchurch Date: Mon, 18 Sep 2023 12:52:34 +0200 Subject: [PATCH] x86/asm: Fix build of UML with KASAN Building UML with KASAN fails since commit 69d4c0d32186 ("entry, kasan, x86: Disallow overriding mem*() functions") with the following errors: $ tools/testing/kunit/kunit.py run --kconfig_add CONFIG_KASAN=y ... ld: mm/kasan/shadow.o: in function `memset': shadow.c:(.text+0x40): multiple definition of `memset'; arch/x86/lib/memset_64.o:(.noinstr.text+0x0): first defined here ld: mm/kasan/shadow.o: in function `memmove': shadow.c:(.text+0x90): multiple definition of `memmove'; arch/x86/lib/memmove_64.o:(.noinstr.text+0x0): first defined here ld: mm/kasan/shadow.o: in function `memcpy': shadow.c:(.text+0x110): multiple definition of `memcpy'; arch/x86/lib/memcpy_64.o:(.noinstr.text+0x0): first defined here UML does not use GENERIC_ENTRY and is still supposed to be allowed to override the mem*() functions, so use weak aliases in that case. Fixes: 69d4c0d32186 ("entry, kasan, x86: Disallow overriding mem*() functions") Signed-off-by: Vincent Whitchurch Signed-off-by: Ingo Molnar Cc: Linus Torvalds Link: https://lore.kernel.org/r/20230918-uml-kasan-v3-1-7ad6db477df6@axis.com --- arch/x86/include/asm/linkage.h | 7 +++++++ arch/x86/lib/memcpy_64.S | 2 +- arch/x86/lib/memmove_64.S | 2 +- arch/x86/lib/memset_64.S | 2 +- 4 files changed, 10 insertions(+), 3 deletions(-) diff --git a/arch/x86/include/asm/linkage.h b/arch/x86/include/asm/linkage.h index 5ff49fd..571fe4d 100644 --- a/arch/x86/include/asm/linkage.h +++ b/arch/x86/include/asm/linkage.h @@ -105,6 +105,13 @@ CFI_POST_PADDING \ SYM_FUNC_END(__cfi_##name) +/* UML needs to be able to override memcpy() and friends for KASAN. */ +#ifdef CONFIG_UML +# define SYM_FUNC_ALIAS_MEMFUNC SYM_FUNC_ALIAS_WEAK +#else +# define SYM_FUNC_ALIAS_MEMFUNC SYM_FUNC_ALIAS +#endif + /* SYM_TYPED_FUNC_START -- use for indirectly called globals, w/ CFI type */ #define SYM_TYPED_FUNC_START(name) \ SYM_TYPED_START(name, SYM_L_GLOBAL, SYM_F_ALIGN) \ diff --git a/arch/x86/lib/memcpy_64.S b/arch/x86/lib/memcpy_64.S index 8f95fb2..76697df 100644 --- a/arch/x86/lib/memcpy_64.S +++ b/arch/x86/lib/memcpy_64.S @@ -40,7 +40,7 @@ SYM_TYPED_FUNC_START(__memcpy) SYM_FUNC_END(__memcpy) EXPORT_SYMBOL(__memcpy) -SYM_FUNC_ALIAS(memcpy, __memcpy) +SYM_FUNC_ALIAS_MEMFUNC(memcpy, __memcpy) EXPORT_SYMBOL(memcpy) SYM_FUNC_START_LOCAL(memcpy_orig) diff --git a/arch/x86/lib/memmove_64.S b/arch/x86/lib/memmove_64.S index 0559b20..ccdf3a5 100644 --- a/arch/x86/lib/memmove_64.S +++ b/arch/x86/lib/memmove_64.S @@ -212,5 +212,5 @@ SYM_FUNC_START(__memmove) SYM_FUNC_END(__memmove) EXPORT_SYMBOL(__memmove) -SYM_FUNC_ALIAS(memmove, __memmove) +SYM_FUNC_ALIAS_MEMFUNC(memmove, __memmove) EXPORT_SYMBOL(memmove) diff --git a/arch/x86/lib/memset_64.S b/arch/x86/lib/memset_64.S index 7c59a70..3d818b8 100644 --- a/arch/x86/lib/memset_64.S +++ b/arch/x86/lib/memset_64.S @@ -40,7 +40,7 @@ SYM_FUNC_START(__memset) SYM_FUNC_END(__memset) EXPORT_SYMBOL(__memset) -SYM_FUNC_ALIAS(memset, __memset) +SYM_FUNC_ALIAS_MEMFUNC(memset, __memset) EXPORT_SYMBOL(memset) SYM_FUNC_START_LOCAL(memset_orig) -- 2.7.4