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authorMasahiro Yamada <masahiroy@kernel.org>2023-10-08 02:04:46 +0900
committerMasahiro Yamada <masahiroy@kernel.org>2023-10-18 17:16:09 +0900
commitbd78c9d714208fb5d989bd8ad007ff0e2bcfb2a9 (patch)
tree1aeef6ad1c57c6a28f3a7b68a1a37d0695fbc5d3 /scripts
parentac96a15a0f0c8812a3aaa587b871cd5527f6d736 (diff)
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>
Diffstat (limited to 'scripts')
-rw-r--r--scripts/mod/modpost.c13
-rw-r--r--scripts/mod/modpost.h25
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 */