Rewrite `arch_elf_pt_proc' and `arch_check_elf' using a union to access
the ELF file header.
Signed-off-by: Maciej W. Rozycki <macro@xxxxxxxxxx>
---
linux-mips-elf-ehdr.diff
Index: linux-sfr-test/arch/mips/kernel/elf.c
===================================================================
--- linux-sfr-test.orig/arch/mips/kernel/elf.c 2015-09-04 22:46:08.374274000 +0100
+++ linux-sfr-test/arch/mips/kernel/elf.c 2015-09-04 22:47:56.448146000 +0100
@@ -68,15 +68,23 @@ static struct mode_req none_req = { true
int arch_elf_pt_proc(void *_ehdr, void *_phdr, struct file *elf,
bool is_interp, struct arch_elf_state *state)
{
- struct elf32_hdr *ehdr32 = _ehdr;
+ union {
+ struct elf32_hdr e32;
+ struct elf64_hdr e64;
+ } *ehdr = _ehdr;
struct elf32_phdr *phdr32 = _phdr;
struct elf64_phdr *phdr64 = _phdr;
struct mips_elf_abiflags_v0 abiflags;
+ bool elf32;
+ u32 flags;
int ret;
+ elf32 = ehdr->e32.e_ident[EI_CLASS] == ELFCLASS32;
+ flags = elf32 ? ehdr->e32.e_flags : ehdr->e64.e_flags;
+
/* Lets see if this is an O32 ELF */
- if (ehdr32->e_ident[EI_CLASS] == ELFCLASS32) {
- if (ehdr32->e_flags & EF_MIPS_FP64) {
+ if (elf32) {
+ if (flags & EF_MIPS_FP64) {
/*
* Set MIPS_ABI_FP_OLD_64 for EF_MIPS_FP64. We will override it
* later if needed
@@ -123,10 +131,17 @@ int arch_elf_pt_proc(void *_ehdr, void *
int arch_check_elf(void *_ehdr, bool has_interpreter,
struct arch_elf_state *state)
{
- struct elf32_hdr *ehdr = _ehdr;
+ union {
+ struct elf32_hdr e32;
+ struct elf64_hdr e64;
+ } *ehdr = _ehdr;
struct mode_req prog_req, interp_req;
int fp_abi, interp_fp_abi, abi0, abi1, max_abi;
- bool is_mips64;
+ bool elf32;
+ u32 flags;
+
+ elf32 = ehdr->e32.e_ident[EI_CLASS] == ELFCLASS32;
+ flags = elf32 ? ehdr->e32.e_flags : ehdr->e64.e_flags;
if (!config_enabled(CONFIG_MIPS_O32_FP64_SUPPORT))
return 0;
@@ -142,21 +157,18 @@ int arch_check_elf(void *_ehdr, bool has
abi0 = abi1 = fp_abi;
}
- is_mips64 = (ehdr->e_ident[EI_CLASS] == ELFCLASS64) ||
- (ehdr->e_flags & EF_MIPS_ABI2);
+ if (elf32 && !(flags & EF_MIPS_ABI2)) {
+ /* Default to a mode capable of running code expecting FR=0 */
+ state->overall_fp_mode = cpu_has_mips_r6 ? FP_FRE : FP_FR0;
- if (is_mips64) {
+ /* Allow all ABIs we know about */
+ max_abi = MIPS_ABI_FP_64A;
+ } else {
/* MIPS64 code always uses FR=1, thus the default is easy */
state->overall_fp_mode = FP_FR1;
/* Disallow access to the various FPXX & FP64 ABIs */
max_abi = MIPS_ABI_FP_SOFT;
- } else {
- /* Default to a mode capable of running code expecting FR=0 */
- state->overall_fp_mode = cpu_has_mips_r6 ? FP_FRE : FP_FR0;
-
- /* Allow all ABIs we know about */
- max_abi = MIPS_ABI_FP_64A;
}
if ((abi0 > max_abi && abi0 != MIPS_ABI_FP_UNKNOWN) ||
