diff options
| author | Masahiro Yamada <masahiroy@kernel.org> | 2023-06-01 21:09:57 +0900 |
|---|---|---|
| committer | Masahiro Yamada <masahiroy@kernel.org> | 2023-06-02 17:59:52 +0900 |
| commit | 12ca2c67d742d390c0aa1f8c1cfc49469df55ddf (patch) | |
| tree | 797c448de29989a38f9b094babe7e0f473f1e2e0 /scripts/mod/modpost.c | |
| parent | 56a24b8ce6a7f9c4a21b2276a8644f6f3d8fc14d (diff) | |
modpost: detect section mismatch for R_ARM_{MOVW_ABS_NC,MOVT_ABS}
For ARM defconfig (i.e. multi_v7_defconfig), modpost fails to detect
some types of section mismatches.
[test code]
#include <linux/init.h>
int __initdata foo;
int get_foo(void) { return foo; }
It is apparently a bad reference, but modpost does not report anything.
The test code above produces the following relocations.
Relocation section '.rel.text' at offset 0x200 contains 2 entries:
Offset Info Type Sym.Value Sym. Name
00000000 0000062b R_ARM_MOVW_ABS_NC 00000000 .LANCHOR0
00000004 0000062c R_ARM_MOVT_ABS 00000000 .LANCHOR0
Currently, R_ARM_MOVW_ABS_NC and R_ARM_MOVT_ABS are just skipped.
Add code to handle them. I checked arch/arm/kernel/module.c to learn
how the offset is encoded in the instruction.
The referenced symbol in relocation might be a local anchor.
If is_valid_name() returns false, let's search for a better symbol name.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Diffstat (limited to 'scripts/mod/modpost.c')
| -rw-r--r-- | scripts/mod/modpost.c | 11 |
1 files changed, 9 insertions, 2 deletions
diff --git a/scripts/mod/modpost.c b/scripts/mod/modpost.c index e47bba7cfad2..5a5e802b160c 100644 --- a/scripts/mod/modpost.c +++ b/scripts/mod/modpost.c @@ -1078,7 +1078,7 @@ static inline int is_valid_name(struct elf_info *elf, Elf_Sym *sym) /** * Find symbol based on relocation record info. * In some cases the symbol supplied is a valid symbol so - * return refsym. If st_name != 0 we assume this is a valid symbol. + * return refsym. If is_valid_name() == true, we assume this is a valid symbol. * In other cases the symbol needs to be looked up in the symbol table * based on section and address. * **/ @@ -1091,7 +1091,7 @@ static Elf_Sym *find_tosym(struct elf_info *elf, Elf64_Sword addr, Elf64_Sword d; unsigned int relsym_secindex; - if (relsym->st_name != 0) + if (is_valid_name(elf, relsym)) return relsym; /* @@ -1297,6 +1297,13 @@ static int addend_arm_rel(struct elf_info *elf, Elf_Shdr *sechdr, Elf_Rela *r) inst = TO_NATIVE(*(uint32_t *)loc); r->r_addend = inst + sym->st_value; break; + case R_ARM_MOVW_ABS_NC: + case R_ARM_MOVT_ABS: + inst = TO_NATIVE(*(uint32_t *)loc); + offset = sign_extend32(((inst & 0xf0000) >> 4) | (inst & 0xfff), + 15); + r->r_addend = offset + sym->st_value; + break; case R_ARM_PC24: case R_ARM_CALL: case R_ARM_JUMP24: |