From fbf6ad5efe95665c188248b6abee94f4bf296604 Mon Sep 17 00:00:00 2001 From: Ard Biesheuvel Date: Wed, 29 Jun 2022 10:32:46 +0200 Subject: [PATCH] arm64: lds: use PROVIDE instead of conditional definitions Currently, a build with CONFIG_EFI=n and CONFIG_KASAN=y will not complete successfully because of missing symbols. This is due to the fact that the __pi_ prefixed aliases for __memcpy/__memmove were put inside a #ifdef CONFIG_EFI block inadvertently, and are therefore missing from the build in question. These definitions should only be provided when needed, as they will otherwise clutter up the symbol table, kallsyms etc for no reason. Fortunately, instead of using CPP conditionals, we can achieve the same result by using the linker's PROVIDE() directive, which only defines a symbol if it is required to complete the link. So let's use that for all symbols alias definitions. Reported-by: kernel test robot Signed-off-by: Ard Biesheuvel Link: https://lore.kernel.org/r/20220629083246.3729177-1-ardb@kernel.org Signed-off-by: Will Deacon --- arch/arm64/kernel/image-vars.h | 61 +++++++++++++++++----------------- 1 file changed, 30 insertions(+), 31 deletions(-) diff --git a/arch/arm64/kernel/image-vars.h b/arch/arm64/kernel/image-vars.h index 0c381a405bf0..afa69e04e75e 100644 --- a/arch/arm64/kernel/image-vars.h +++ b/arch/arm64/kernel/image-vars.h @@ -10,11 +10,8 @@ #error This file should only be included in vmlinux.lds.S #endif -#ifdef CONFIG_EFI - -__efistub_kernel_size = _edata - _text; -__efistub_primary_entry_offset = primary_entry - _text; - +PROVIDE(__efistub_kernel_size = _edata - _text); +PROVIDE(__efistub_primary_entry_offset = primary_entry - _text); /* * The EFI stub has its own symbol namespace prefixed by __efistub_, to @@ -25,35 +22,37 @@ __efistub_primary_entry_offset = primary_entry - _text; * linked at. The routines below are all implemented in assembler in a * position independent manner */ -__efistub_memcmp = __pi_memcmp; -__efistub_memchr = __pi_memchr; -__efistub_memcpy = __pi_memcpy; -__efistub_memmove = __pi_memmove; -__efistub_memset = __pi_memset; -__efistub_strlen = __pi_strlen; -__efistub_strnlen = __pi_strnlen; -__efistub_strcmp = __pi_strcmp; -__efistub_strncmp = __pi_strncmp; -__efistub_strrchr = __pi_strrchr; -__efistub_dcache_clean_poc = __pi_dcache_clean_poc; +PROVIDE(__efistub_memcmp = __pi_memcmp); +PROVIDE(__efistub_memchr = __pi_memchr); +PROVIDE(__efistub_memcpy = __pi_memcpy); +PROVIDE(__efistub_memmove = __pi_memmove); +PROVIDE(__efistub_memset = __pi_memset); +PROVIDE(__efistub_strlen = __pi_strlen); +PROVIDE(__efistub_strnlen = __pi_strnlen); +PROVIDE(__efistub_strcmp = __pi_strcmp); +PROVIDE(__efistub_strncmp = __pi_strncmp); +PROVIDE(__efistub_strrchr = __pi_strrchr); +PROVIDE(__efistub_dcache_clean_poc = __pi_dcache_clean_poc); -#if defined(CONFIG_KASAN_GENERIC) || defined(CONFIG_KASAN_SW_TAGS) -__efistub___memcpy = __pi_memcpy; -__efistub___memmove = __pi_memmove; -__efistub___memset = __pi_memset; +PROVIDE(__efistub__text = _text); +PROVIDE(__efistub__end = _end); +PROVIDE(__efistub__edata = _edata); +PROVIDE(__efistub_screen_info = screen_info); +PROVIDE(__efistub__ctype = _ctype); -__pi___memcpy = __pi_memcpy; -__pi___memmove = __pi_memmove; -__pi___memset = __pi_memset; -#endif +/* + * The __ prefixed memcpy/memset/memmove symbols are provided by KASAN, which + * instruments the conventional ones. Therefore, any references from the EFI + * stub or other position independent, low level C code should be redirected to + * the non-instrumented versions as well. + */ +PROVIDE(__efistub___memcpy = __pi_memcpy); +PROVIDE(__efistub___memmove = __pi_memmove); +PROVIDE(__efistub___memset = __pi_memset); -__efistub__text = _text; -__efistub__end = _end; -__efistub__edata = _edata; -__efistub_screen_info = screen_info; -__efistub__ctype = _ctype; - -#endif +PROVIDE(__pi___memcpy = __pi_memcpy); +PROVIDE(__pi___memmove = __pi_memmove); +PROVIDE(__pi___memset = __pi_memset); #ifdef CONFIG_KVM