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authorMasahiro Yamada <masahiroy@kernel.org>2023-06-01 15:09:57 +0300
committerMasahiro Yamada <masahiroy@kernel.org>2023-06-02 11:59:52 +0300
commit12ca2c67d742d390c0aa1f8c1cfc49469df55ddf (patch)
tree797c448de29989a38f9b094babe7e0f473f1e2e0 /scripts/mod
parent56a24b8ce6a7f9c4a21b2276a8644f6f3d8fc14d (diff)
downloadlinux-12ca2c67d742d390c0aa1f8c1cfc49469df55ddf.tar.xz
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')
-rw-r--r--scripts/mod/modpost.c11
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: