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linux/arch/mips/kernel/binfmt_elfo32.c
Paul Burton 597ce1723e MIPS: Support for 64-bit FP with O32 binaries 
CPUs implementing MIPS32 R2 may include a 64-bit FPU, just as MIPS64 CPUs
do. In order to preserve backwards compatibility a 64-bit FPU will act
like a 32-bit FPU (by accessing doubles from the least significant 32
bits of an even-odd pair of FP registers) when the Status.FR bit is
zero, again just like a mips64 CPU. The standard O32 ABI is defined
expecting a 32-bit FPU, however recent toolchains support use of a
64-bit FPU from an O32 MIPS32 executable. When an ELF executable is
built to use a 64-bit FPU a new flag (EF_MIPS_FP64) is set in the ELF
header.

With this patch the kernel will check the EF_MIPS_FP64 flag when
executing an O32 binary, and set Status.FR accordingly. The addition
of O32 64-bit FP support lessens the opportunity for optimisation in
the FPU emulator, so a CONFIG_MIPS_O32_FP64_SUPPORT Kconfig option is
introduced to allow this support to be disabled for those that don't
require it.

Inspired by an earlier patch by Leonid Yegoshin, but implemented more
cleanly & correctly.

Signed-off-by: Paul Burton <paul.burton@imgtec.com>
Cc: linux-mips@linux-mips.org
Cc: Paul Burton <paul.burton@imgtec.com>
Patchwork: https://patchwork.linux-mips.org/patch/6154/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2014-01-13 23:40:56 +01:00

191 lines
5.2 KiB
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/*
* Support for o32 Linux/MIPS ELF binaries.
*
* Copyright (C) 1999, 2001 Ralf Baechle
* Copyright (C) 1999, 2001 Silicon Graphics, Inc.
*
* Heavily inspired by the 32-bit Sparc compat code which is
* Copyright (C) 1995, 1996, 1997, 1998 David S. Miller (davem@redhat.com)
* Copyright (C) 1995, 1996, 1997, 1998 Jakub Jelinek (jj@ultra.linux.cz)
*/
#define ELF_ARCH EM_MIPS
#define ELF_CLASS ELFCLASS32
#ifdef __MIPSEB__
#define ELF_DATA ELFDATA2MSB;
#else /* __MIPSEL__ */
#define ELF_DATA ELFDATA2LSB;
#endif
/* ELF register definitions */
#define ELF_NGREG 45
#define ELF_NFPREG 33
typedef unsigned int elf_greg_t;
typedef elf_greg_t elf_gregset_t[ELF_NGREG];
typedef double elf_fpreg_t;
typedef elf_fpreg_t elf_fpregset_t[ELF_NFPREG];
/*
* In order to be sure that we don't attempt to execute an O32 binary which
* requires 64 bit FP (FR=1) on a system which does not support it we refuse
* to execute any binary which has bits specified by the following macro set
* in its ELF header flags.
*/
#ifdef CONFIG_MIPS_O32_FP64_SUPPORT
# define __MIPS_O32_FP64_MUST_BE_ZERO 0
#else
# define __MIPS_O32_FP64_MUST_BE_ZERO EF_MIPS_FP64
#endif
/*
* This is used to ensure we don't load something for the wrong architecture.
*/
#define elf_check_arch(hdr) \
({ \
int __res = 1; \
struct elfhdr *__h = (hdr); \
\
if (__h->e_machine != EM_MIPS) \
__res = 0; \
if (__h->e_ident[EI_CLASS] != ELFCLASS32) \
__res = 0; \
if ((__h->e_flags & EF_MIPS_ABI2) != 0) \
__res = 0; \
if (((__h->e_flags & EF_MIPS_ABI) != 0) && \
((__h->e_flags & EF_MIPS_ABI) != EF_MIPS_ABI_O32)) \
__res = 0; \
if (__h->e_flags & __MIPS_O32_FP64_MUST_BE_ZERO) \
__res = 0; \
\
__res; \
})
#ifdef CONFIG_KVM_GUEST
#define TASK32_SIZE 0x3fff8000UL
#else
#define TASK32_SIZE 0x7fff8000UL
#endif
#undef ELF_ET_DYN_BASE
#define ELF_ET_DYN_BASE (TASK32_SIZE / 3 * 2)
#include <asm/processor.h>
/*
* When this file is selected, we are definitely running a 64bit kernel.
* So using the right regs define in asm/reg.h
*/
#define WANT_COMPAT_REG_H
/* These MUST be defined before elf.h gets included */
extern void elf32_core_copy_regs(elf_gregset_t grp, struct pt_regs *regs);
#define ELF_CORE_COPY_REGS(_dest, _regs) elf32_core_copy_regs(_dest, _regs);
#define ELF_CORE_COPY_TASK_REGS(_tsk, _dest) \
({ \
int __res = 1; \
elf32_core_copy_regs(*(_dest), task_pt_regs(_tsk)); \
__res; \
})
#include <linux/module.h>
#include <linux/elfcore.h>
#include <linux/compat.h>
#include <linux/math64.h>
#define elf_prstatus elf_prstatus32
struct elf_prstatus32
{
struct elf_siginfo pr_info; /* Info associated with signal */
short pr_cursig; /* Current signal */
unsigned int pr_sigpend; /* Set of pending signals */
unsigned int pr_sighold; /* Set of held signals */
pid_t pr_pid;
pid_t pr_ppid;
pid_t pr_pgrp;
pid_t pr_sid;
struct compat_timeval pr_utime; /* User time */
struct compat_timeval pr_stime; /* System time */
struct compat_timeval pr_cutime;/* Cumulative user time */
struct compat_timeval pr_cstime;/* Cumulative system time */
elf_gregset_t pr_reg; /* GP registers */
int pr_fpvalid; /* True if math co-processor being used. */
};
#define elf_prpsinfo elf_prpsinfo32
struct elf_prpsinfo32
{
char pr_state; /* numeric process state */
char pr_sname; /* char for pr_state */
char pr_zomb; /* zombie */
char pr_nice; /* nice val */
unsigned int pr_flag; /* flags */
__kernel_uid_t pr_uid;
__kernel_gid_t pr_gid;
pid_t pr_pid, pr_ppid, pr_pgrp, pr_sid;
/* Lots missing */
char pr_fname[16]; /* filename of executable */
char pr_psargs[ELF_PRARGSZ]; /* initial part of arg list */
};
#define elf_caddr_t u32
#define init_elf_binfmt init_elf32_binfmt
#define jiffies_to_timeval jiffies_to_compat_timeval
static inline void
jiffies_to_compat_timeval(unsigned long jiffies, struct compat_timeval *value)
{
/*
* Convert jiffies to nanoseconds and separate with
* one divide.
*/
u64 nsec = (u64)jiffies * TICK_NSEC;
u32 rem;
value->tv_sec = div_u64_rem(nsec, NSEC_PER_SEC, &rem);
value->tv_usec = rem / NSEC_PER_USEC;
}
void elf32_core_copy_regs(elf_gregset_t grp, struct pt_regs *regs)
{
int i;
for (i = 0; i < EF_R0; i++)
grp[i] = 0;
grp[EF_R0] = 0;
for (i = 1; i <= 31; i++)
grp[EF_R0 + i] = (elf_greg_t) regs->regs[i];
grp[EF_R26] = 0;
grp[EF_R27] = 0;
grp[EF_LO] = (elf_greg_t) regs->lo;
grp[EF_HI] = (elf_greg_t) regs->hi;
grp[EF_CP0_EPC] = (elf_greg_t) regs->cp0_epc;
grp[EF_CP0_BADVADDR] = (elf_greg_t) regs->cp0_badvaddr;
grp[EF_CP0_STATUS] = (elf_greg_t) regs->cp0_status;
grp[EF_CP0_CAUSE] = (elf_greg_t) regs->cp0_cause;
#ifdef EF_UNUSED0
grp[EF_UNUSED0] = 0;
#endif
}
MODULE_DESCRIPTION("Binary format loader for compatibility with o32 Linux/MIPS binaries");
MODULE_AUTHOR("Ralf Baechle (ralf@linux-mips.org)");
#undef MODULE_DESCRIPTION
#undef MODULE_AUTHOR
#undef TASK_SIZE
#define TASK_SIZE TASK_SIZE32
#undef cputime_to_timeval
#define cputime_to_timeval cputime_to_compat_timeval
static __inline__ void
cputime_to_compat_timeval(const cputime_t cputime, struct compat_timeval *value)
{
unsigned long jiffies = cputime_to_jiffies(cputime);
value->tv_usec = (jiffies % HZ) * (1000000L / HZ);
value->tv_sec = jiffies / HZ;
}
#include "../../../fs/binfmt_elf.c"
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