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| author | Masahiro Yamada <masahiroy@kernel.org> | 2023-10-08 02:04:46 +0900 |
|---|---|---|
| committer | Masahiro Yamada <masahiroy@kernel.org> | 2023-10-18 17:16:09 +0900 |
| commit | bd78c9d714208fb5d989bd8ad007ff0e2bcfb2a9 (patch) | |
| tree | 1aeef6ad1c57c6a28f3a7b68a1a37d0695fbc5d3 | |
| parent | ac96a15a0f0c8812a3aaa587b871cd5527f6d736 (diff) | |
| download | linux-bd78c9d714208fb5d989bd8ad007ff0e2bcfb2a9.tar.gz linux-bd78c9d714208fb5d989bd8ad007ff0e2bcfb2a9.tar.bz2 linux-bd78c9d714208fb5d989bd8ad007ff0e2bcfb2a9.zip | |
modpost: define TO_NATIVE() using bswap_* functions
The current TO_NATIVE() has some limitations:
1) You cannot cast the argument.
2) You cannot pass a variable marked as 'const'.
3) Passing an array is a bug, but it is not detected.
Impelement TO_NATIVE() using bswap_*() functions. These are GNU
extensions. If we face portability issues, we can port the code from
include/uapi/linux/swab.h.
With this change, get_rel_type_and_sym() can be simplified by casting
the arguments directly.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
| -rw-r--r-- | scripts/mod/modpost.c | 13 | ||||
| -rw-r--r-- | scripts/mod/modpost.h | 25 |
2 files changed, 16 insertions, 22 deletions
diff --git a/scripts/mod/modpost.c b/scripts/mod/modpost.c index 2f3b0fe6f68d..99476a9695c5 100644 --- a/scripts/mod/modpost.c +++ b/scripts/mod/modpost.c @@ -1410,15 +1410,10 @@ static void get_rel_type_and_sym(struct elf_info *elf, uint64_t r_info, return; } - if (is_64bit) { - Elf64_Xword r_info64 = r_info; - - r_info = TO_NATIVE(r_info64); - } else { - Elf32_Word r_info32 = r_info; - - r_info = TO_NATIVE(r_info32); - } + if (is_64bit) + r_info = TO_NATIVE((Elf64_Xword)r_info); + else + r_info = TO_NATIVE((Elf32_Word)r_info); *r_type = ELF_R_TYPE(r_info); *r_sym = ELF_R_SYM(r_info); diff --git a/scripts/mod/modpost.h b/scripts/mod/modpost.h index 6413f26fcb6b..1392afec118c 100644 --- a/scripts/mod/modpost.h +++ b/scripts/mod/modpost.h @@ -1,4 +1,5 @@ /* SPDX-License-Identifier: GPL-2.0 */ +#include <byteswap.h> #include <stdbool.h> #include <stdio.h> #include <stdlib.h> @@ -51,21 +52,19 @@ #define ELF_R_TYPE ELF64_R_TYPE #endif -#if KERNEL_ELFDATA != HOST_ELFDATA +#define bswap(x) \ +({ \ + _Static_assert(sizeof(x) == 1 || sizeof(x) == 2 || \ + sizeof(x) == 4 || sizeof(x) == 8, "bug"); \ + (typeof(x))(sizeof(x) == 2 ? bswap_16(x) : \ + sizeof(x) == 4 ? bswap_32(x) : \ + sizeof(x) == 8 ? bswap_64(x) : \ + x); \ +}) -static inline void __endian(const void *src, void *dest, unsigned int size) -{ - unsigned int i; - for (i = 0; i < size; i++) - ((unsigned char*)dest)[i] = ((unsigned char*)src)[size - i-1]; -} +#if KERNEL_ELFDATA != HOST_ELFDATA -#define TO_NATIVE(x) \ -({ \ - typeof(x) __x; \ - __endian(&(x), &(__x), sizeof(__x)); \ - __x; \ -}) +#define TO_NATIVE(x) (bswap(x)) #else /* endianness matches */ |