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MIPS: ELF: Set FP mode according to .MIPS.abiflags 

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@imgtec.com>
Cc: linux-mips@linux-mips.org
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: linux-fsdevel@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/7681/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
This commit is contained in:
Paul Burton 2014-09-11 08:30:22 +01:00 committed by Ralf Baechle
parent 6cd962292d
commit 90cee759f0
4 changed files with 211 additions and 20 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

1
arch/mips/Kconfig
View File

@ -53,6 +53,7 @@ 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"

50
arch/mips/include/asm/elf.h
View File

@ -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 */

7
arch/mips/kernel/Makefile
View File

@ -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

173
arch/mips/kernel/elf.c Normal file
View File

@ -0,0 +1,173 @@
/*
* Copyright (C) 2014 Imagination Technologies
* Author: Paul Burton <paul.burton@imgtec.com>
*
* 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();
}
}