This patch reads the .MIPS.abiflags section when it is present, and sets
the FP mode of the task accordingly. Any loaded ELF files which do not
contain a .MIPS.abiflags section will continue to observe the previous
behaviour, that is FR=1 if EF_MIPS_FP64 is set else FR=0.
Signed-off-by: Paul Burton <paul.burton@xxxxxxxxxx>
---
arch/mips/Kconfig | 1 +
arch/mips/include/asm/elf.h | 50 ++++++++-----
arch/mips/kernel/Makefile | 7 +-
arch/mips/kernel/elf.c | 173 ++++++++++++++++++++++++++++++++++++++++++++
4 files changed, 211 insertions(+), 20 deletions(-)
create mode 100644 arch/mips/kernel/elf.c
diff --git a/arch/mips/Kconfig b/arch/mips/Kconfig
index 900c7e5..8d73ed0 100644
--- a/arch/mips/Kconfig
+++ b/arch/mips/Kconfig
@@ -52,6 +52,7 @@ config MIPS
select HAVE_CC_STACKPROTECTOR
select CPU_PM if CPU_IDLE
select ARCH_HAS_TICK_BROADCAST if GENERIC_CLOCKEVENTS_BROADCAST
+ select ARCH_BINFMT_ELF_STATE
menu "Machine selection"
diff --git a/arch/mips/include/asm/elf.h b/arch/mips/include/asm/elf.h
index bfa4bbd..eb4d95d 100644
--- a/arch/mips/include/asm/elf.h
+++ b/arch/mips/include/asm/elf.h
@@ -8,6 +8,8 @@
#ifndef _ASM_ELF_H
#define _ASM_ELF_H
+#include <linux/fs.h>
+#include <uapi/linux/elf.h>
/* ELF header e_flags defines. */
/* MIPS architecture level. */
@@ -287,18 +289,13 @@ extern struct mips_abi mips_abi_n32;
#ifdef CONFIG_32BIT
-#define SET_PERSONALITY(ex) \
+#define SET_PERSONALITY2(ex, state) \
do { \
- if ((ex).e_flags & EF_MIPS_FP64) \
- clear_thread_flag(TIF_32BIT_FPREGS); \
- else \
- set_thread_flag(TIF_32BIT_FPREGS); \
- \
- clear_thread_flag(TIF_HYBRID_FPREGS); \
- \
if (personality(current->personality) != PER_LINUX) \
set_personality(PER_LINUX); \
\
+ mips_set_personality_fp(state); \
+ \
current->thread.abi = &mips_abi; \
} while (0)
@@ -318,35 +315,34 @@ do { \
#endif
#ifdef CONFIG_MIPS32_O32
-#define __SET_PERSONALITY32_O32(ex) \
+#define __SET_PERSONALITY32_O32(ex, state) \
do { \
set_thread_flag(TIF_32BIT_REGS); \
set_thread_flag(TIF_32BIT_ADDR); \
\
- if (!((ex).e_flags & EF_MIPS_FP64)) \
- set_thread_flag(TIF_32BIT_FPREGS); \
+ mips_set_personality_fp(state); \
\
current->thread.abi = &mips_abi_32; \
} while (0)
#else
-#define __SET_PERSONALITY32_O32(ex) \
+#define __SET_PERSONALITY32_O32(ex, state) \
do { } while (0)
#endif
#ifdef CONFIG_MIPS32_COMPAT
-#define __SET_PERSONALITY32(ex) \
+#define __SET_PERSONALITY32(ex, state) \
do { \
if ((((ex).e_flags & EF_MIPS_ABI2) != 0) && \
((ex).e_flags & EF_MIPS_ABI) == 0) \
__SET_PERSONALITY32_N32(); \
else \
- __SET_PERSONALITY32_O32(ex); \
+ __SET_PERSONALITY32_O32(ex, state); \
} while (0)
#else
-#define __SET_PERSONALITY32(ex) do { } while (0)
+#define __SET_PERSONALITY32(ex, state) do { } while (0)
#endif
-#define SET_PERSONALITY(ex) \
+#define SET_PERSONALITY2(ex, state) \
do { \
unsigned int p; \
\
@@ -356,7 +352,7 @@ do { \
clear_thread_flag(TIF_32BIT_ADDR); \
\
if ((ex).e_ident[EI_CLASS] == ELFCLASS32) \
- __SET_PERSONALITY32(ex); \
+ __SET_PERSONALITY32(ex, state); \
else \
current->thread.abi = &mips_abi; \
\
@@ -418,4 +414,24 @@ struct mm_struct;
extern unsigned long arch_randomize_brk(struct mm_struct *mm);
#define arch_randomize_brk arch_randomize_brk
+struct arch_elf_state {
+ int fp_abi;
+ int interp_fp_abi;
+ int overall_abi;
+};
+
+#define INIT_ARCH_ELF_STATE { \
+ .fp_abi = -1, \
+ .interp_fp_abi = -1, \
+ .overall_abi = -1, \
+}
+
+extern int arch_elf_pt_proc(void *ehdr, void *phdr, struct file *elf,
+ bool is_interp, struct arch_elf_state *state);
+
+extern int arch_check_elf(void *ehdr, bool has_interpreter,
+ struct arch_elf_state *state);
+
+extern void mips_set_personality_fp(struct arch_elf_state *state);
+
#endif /* _ASM_ELF_H */
diff --git a/arch/mips/kernel/Makefile b/arch/mips/kernel/Makefile
index 008a2fe..53a78d9 100644
--- a/arch/mips/kernel/Makefile
+++ b/arch/mips/kernel/Makefile
@@ -4,9 +4,10 @@
extra-y := head.o vmlinux.lds
-obj-y += cpu-probe.o branch.o entry.o genex.o idle.o irq.o process.o \
- prom.o ptrace.o reset.o setup.o signal.o syscall.o \
- time.o topology.o traps.o unaligned.o watch.o vdso.o
+obj-y += cpu-probe.o branch.o elf.o entry.o genex.o idle.o irq.o \
+ process.o prom.o ptrace.o reset.o setup.o signal.o \
+ syscall.o time.o topology.o traps.o unaligned.o watch.o \
+ vdso.o
ifdef CONFIG_FUNCTION_TRACER
CFLAGS_REMOVE_ftrace.o = -pg
diff --git a/arch/mips/kernel/elf.c b/arch/mips/kernel/elf.c
new file mode 100644
index 0000000..0933e07
--- /dev/null
+++ b/arch/mips/kernel/elf.c
@@ -0,0 +1,173 @@
+/*
+ * Copyright (C) 2014 Imagination Technologies
+ * Author: Paul Burton <paul.burton@xxxxxxxxxx>
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the
+ * Free Software Foundation; either version 2 of the License, or (at your
+ * option) any later version.
+ */
+
+#include <linux/elf.h>
+#include <linux/sched.h>
+
+enum {
+ FP_ERROR = -1,
+ FP_DOUBLE_64A = -2,
+};
+
+int arch_elf_pt_proc(void *_ehdr, void *_phdr, struct file *elf,
+ bool is_interp, struct arch_elf_state *state)
+{
+ struct elfhdr *ehdr = _ehdr;
+ struct elf_phdr *phdr = _phdr;
+ struct mips_elf_abiflags_v0 abiflags;
+ int ret;
+
+ if (config_enabled(CONFIG_64BIT) &&
+ (ehdr->e_ident[EI_CLASS] != ELFCLASS32))
+ return 0;
+ if (phdr->p_type != PT_MIPS_ABIFLAGS)
+ return 0;
+ if (phdr->p_filesz < sizeof(abiflags))
+ return -EINVAL;
+
+ ret = kernel_read(elf, phdr->p_offset, (char *)&abiflags,
+ sizeof(abiflags));
+ if (ret < 0)
+ return ret;
+ if (ret != sizeof(abiflags))
+ return -EIO;
+
+ /* Record the required FP ABIs for use by mips_check_elf */
+ if (is_interp)
+ state->interp_fp_abi = abiflags.fp_abi;
+ else
+ state->fp_abi = abiflags.fp_abi;
+
+ return 0;
+}
+
+static inline unsigned get_fp_abi(struct elfhdr *ehdr, int in_abi)
+{
+ /* If the ABI requirement is provided, simply return that */
+ if (in_abi != -1)
+ return in_abi;
+
+ /* If the EF_MIPS_FP64 flag was set, return MIPS_ABI_FP_64 */
+ if (ehdr->e_flags & EF_MIPS_FP64)
+ return MIPS_ABI_FP_64;
+
+ /* Default to MIPS_ABI_FP_DOUBLE */
+ return MIPS_ABI_FP_DOUBLE;
+}
+
+int arch_check_elf(void *_ehdr, bool has_interpreter,
+ struct arch_elf_state *state)
+{
+ struct elfhdr *ehdr = _ehdr;
+ unsigned fp_abi, interp_fp_abi, abi0, abi1;
+
+ /* Ignore non-O32 binaries */
+ if (config_enabled(CONFIG_64BIT) &&
+ (ehdr->e_ident[EI_CLASS] != ELFCLASS32))
+ return 0;
+
+ fp_abi = get_fp_abi(ehdr, state->fp_abi);
+
+ if (has_interpreter) {
+ interp_fp_abi = get_fp_abi(ehdr, state->interp_fp_abi);
+
+ abi0 = min(fp_abi, interp_fp_abi);
+ abi1 = max(fp_abi, interp_fp_abi);
+ } else {
+ abi0 = abi1 = fp_abi;
+ }
+
+ state->overall_abi = FP_ERROR;
+
+ if (abi0 == abi1) {
+ state->overall_abi = abi0;
+ } else if (abi0 == MIPS_ABI_FP_ANY) {
+ state->overall_abi = abi1;
+ } else if (abi0 == MIPS_ABI_FP_DOUBLE) {
+ switch (abi1) {
+ case MIPS_ABI_FP_XX:
+ state->overall_abi = MIPS_ABI_FP_DOUBLE;
+ break;
+
+ case MIPS_ABI_FP_64A:
+ state->overall_abi = FP_DOUBLE_64A;
+ break;
+ }
+ } else if (abi0 == MIPS_ABI_FP_SINGLE ||
+ abi0 == MIPS_ABI_FP_SOFT) {
+ /* Cannot link with other ABIs */
+ } else if (abi0 == MIPS_ABI_FP_OLD_64) {
+ switch (abi1) {
+ case MIPS_ABI_FP_XX:
+ case MIPS_ABI_FP_64:
+ case MIPS_ABI_FP_64A:
+ state->overall_abi = MIPS_ABI_FP_64;
+ break;
+ }
+ } else if (abi0 == MIPS_ABI_FP_XX ||
+ abi0 == MIPS_ABI_FP_64 ||
+ abi0 == MIPS_ABI_FP_64A) {
+ state->overall_abi = MIPS_ABI_FP_64;
+ }
+
+ switch (state->overall_abi) {
+ case MIPS_ABI_FP_64:
+ case MIPS_ABI_FP_64A:
+ case FP_DOUBLE_64A:
+ if (!config_enabled(CONFIG_MIPS_O32_FP64_SUPPORT))
+ return -ELIBBAD;
+ break;
+
+ case FP_ERROR:
+ return -ELIBBAD;
+ }
+
+ return 0;
+}
+
+void mips_set_personality_fp(struct arch_elf_state *state)
+{
+ switch (state->overall_abi) {
+ case MIPS_ABI_FP_DOUBLE:
+ case MIPS_ABI_FP_SINGLE:
+ case MIPS_ABI_FP_SOFT:
+ /* FR=0 */
+ set_thread_flag(TIF_32BIT_FPREGS);
+ clear_thread_flag(TIF_HYBRID_FPREGS);
+ break;
+
+ case FP_DOUBLE_64A:
+ /* FR=1, FRE=1 */
+ clear_thread_flag(TIF_32BIT_FPREGS);
+ set_thread_flag(TIF_HYBRID_FPREGS);
+ break;
+
+ case MIPS_ABI_FP_64:
+ case MIPS_ABI_FP_64A:
+ /* FR=1, FRE=0 */
+ clear_thread_flag(TIF_32BIT_FPREGS);
+ clear_thread_flag(TIF_HYBRID_FPREGS);
+ break;
+
+ case MIPS_ABI_FP_XX:
+ case MIPS_ABI_FP_ANY:
+ if (!config_enabled(CONFIG_MIPS_O32_FP64_SUPPORT))
+ set_thread_flag(TIF_32BIT_FPREGS);
+ else
+ clear_thread_flag(TIF_32BIT_FPREGS);
+
+ clear_thread_flag(TIF_HYBRID_FPREGS);
+ break;
+
+ default:
+ case FP_ERROR:
+ BUG();
+ }
+}
--
2.0.4
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