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Per discussion on arm@, the compiler generates misaligned

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relocations. Cope with memcpy when needed.

Submitted by: fabient@ (plus changes suggested by thread)
This commit is contained in:
Warner Losh 2014-08-09 22:51:26 +00:00
parent f7469d3e52
commit a17de72b25
1 changed files with 33 additions and 5 deletions
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38
sys/arm/arm/elf_machdep.c
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@ -120,6 +120,34 @@ elf32_dump_thread(struct thread *td __unused, void *dst __unused,
{
}
/*
* It is possible for the compiler to emit relocations for unaligned data.
* We handle this situation with these inlines.
*/
#define RELOC_ALIGNED_P(x) \
(((uintptr_t)(x) & (sizeof(void *) - 1)) == 0)
static __inline Elf_Addr
load_ptr(Elf_Addr *where)
{
Elf_Addr res;
if (RELOC_ALIGNED_P(where))
return *where;
memcpy(&res, where, sizeof(res));
return (res);
}
static __inline void
store_ptr(Elf_Addr *where, Elf_Addr val)
{
if (RELOC_ALIGNED_P(where))
*where = val;
else
memcpy(where, &val, sizeof(val));
}
#undef RELOC_ALIGNED_P
/* Process one elf relocation with addend. */
static int
@ -137,7 +165,7 @@ elf_reloc_internal(linker_file_t lf, Elf_Addr relocbase, const void *data,
case ELF_RELOC_REL:
rel = (const Elf_Rel *)data;
where = (Elf_Addr *) (relocbase + rel->r_offset);
addend = *where;
addend = load_ptr(where);
rtype = ELF_R_TYPE(rel->r_info);
symidx = ELF_R_SYM(rel->r_info);
break;
@ -155,8 +183,8 @@ elf_reloc_internal(linker_file_t lf, Elf_Addr relocbase, const void *data,
if (local) {
if (rtype == R_ARM_RELATIVE) { /* A + B */
addr = elf_relocaddr(lf, relocbase + addend);
if (*where != addr)
*where = addr;
if (load_ptr(where) != addr)
store_ptr(where, addr);
}
return (0);
}
@ -170,7 +198,7 @@ elf_reloc_internal(linker_file_t lf, Elf_Addr relocbase, const void *data,
addr = lookup(lf, symidx, 1);
if (addr == 0)
return -1;
*where += addr;
store_ptr(where, addr + load_ptr(where));
break;
case R_ARM_COPY: /* none */
@ -185,7 +213,7 @@ elf_reloc_internal(linker_file_t lf, Elf_Addr relocbase, const void *data,
case R_ARM_JUMP_SLOT:
addr = lookup(lf, symidx, 1);
if (addr) {
*where = addr;
store_ptr(where, addr);
return (0);
}
return (-1);