177 lines
4.1 KiB
C
177 lines
4.1 KiB
C
/* MN10300 FPU management
|
|
*
|
|
* Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
|
|
* Written by David Howells (dhowells@redhat.com)
|
|
*
|
|
* This program is free software; you can redistribute it and/or
|
|
* modify it under the terms of the GNU General Public Licence
|
|
* as published by the Free Software Foundation; either version
|
|
* 2 of the Licence, or (at your option) any later version.
|
|
*/
|
|
#include <asm/uaccess.h>
|
|
#include <asm/fpu.h>
|
|
#include <asm/elf.h>
|
|
#include <asm/exceptions.h>
|
|
#include <asm/system.h>
|
|
|
|
#ifdef CONFIG_LAZY_SAVE_FPU
|
|
struct task_struct *fpu_state_owner;
|
|
#endif
|
|
|
|
/*
|
|
* error functions in FPU disabled exception
|
|
*/
|
|
asmlinkage void fpu_disabled_in_kernel(struct pt_regs *regs)
|
|
{
|
|
die_if_no_fixup("An FPU Disabled exception happened in kernel space\n",
|
|
regs, EXCEP_FPU_DISABLED);
|
|
}
|
|
|
|
/*
|
|
* handle an FPU operational exception
|
|
* - there's a possibility that if the FPU is asynchronous, the signal might
|
|
* be meant for a process other than the current one
|
|
*/
|
|
asmlinkage void fpu_exception(struct pt_regs *regs, enum exception_code code)
|
|
{
|
|
struct task_struct *tsk = current;
|
|
siginfo_t info;
|
|
u32 fpcr;
|
|
|
|
if (!user_mode(regs))
|
|
die_if_no_fixup("An FPU Operation exception happened in"
|
|
" kernel space\n",
|
|
regs, code);
|
|
|
|
if (!is_using_fpu(tsk))
|
|
die_if_no_fixup("An FPU Operation exception happened,"
|
|
" but the FPU is not in use",
|
|
regs, code);
|
|
|
|
info.si_signo = SIGFPE;
|
|
info.si_errno = 0;
|
|
info.si_addr = (void *) tsk->thread.uregs->pc;
|
|
info.si_code = FPE_FLTINV;
|
|
|
|
unlazy_fpu(tsk);
|
|
|
|
fpcr = tsk->thread.fpu_state.fpcr;
|
|
|
|
if (fpcr & FPCR_EC_Z)
|
|
info.si_code = FPE_FLTDIV;
|
|
else if (fpcr & FPCR_EC_O)
|
|
info.si_code = FPE_FLTOVF;
|
|
else if (fpcr & FPCR_EC_U)
|
|
info.si_code = FPE_FLTUND;
|
|
else if (fpcr & FPCR_EC_I)
|
|
info.si_code = FPE_FLTRES;
|
|
|
|
force_sig_info(SIGFPE, &info, tsk);
|
|
}
|
|
|
|
/*
|
|
* save the FPU state to a signal context
|
|
*/
|
|
int fpu_setup_sigcontext(struct fpucontext *fpucontext)
|
|
{
|
|
struct task_struct *tsk = current;
|
|
|
|
if (!is_using_fpu(tsk))
|
|
return 0;
|
|
|
|
/* transfer the current FPU state to memory and cause fpu_init() to be
|
|
* triggered by the next attempted FPU operation by the current
|
|
* process.
|
|
*/
|
|
preempt_disable();
|
|
|
|
#ifndef CONFIG_LAZY_SAVE_FPU
|
|
if (tsk->thread.fpu_flags & THREAD_HAS_FPU) {
|
|
fpu_save(&tsk->thread.fpu_state);
|
|
tsk->thread.uregs->epsw &= ~EPSW_FE;
|
|
tsk->thread.fpu_flags &= ~THREAD_HAS_FPU;
|
|
}
|
|
#else /* !CONFIG_LAZY_SAVE_FPU */
|
|
if (fpu_state_owner == tsk) {
|
|
fpu_save(&tsk->thread.fpu_state);
|
|
fpu_state_owner->thread.uregs->epsw &= ~EPSW_FE;
|
|
fpu_state_owner = NULL;
|
|
}
|
|
#endif /* !CONFIG_LAZY_SAVE_FPU */
|
|
|
|
preempt_enable();
|
|
|
|
/* we no longer have a valid current FPU state */
|
|
clear_using_fpu(tsk);
|
|
|
|
/* transfer the saved FPU state onto the userspace stack */
|
|
if (copy_to_user(fpucontext,
|
|
&tsk->thread.fpu_state,
|
|
min(sizeof(struct fpu_state_struct),
|
|
sizeof(struct fpucontext))))
|
|
return -1;
|
|
|
|
return 1;
|
|
}
|
|
|
|
/*
|
|
* kill a process's FPU state during restoration after signal handling
|
|
*/
|
|
void fpu_kill_state(struct task_struct *tsk)
|
|
{
|
|
/* disown anything left in the FPU */
|
|
preempt_disable();
|
|
|
|
#ifndef CONFIG_LAZY_SAVE_FPU
|
|
if (tsk->thread.fpu_flags & THREAD_HAS_FPU) {
|
|
tsk->thread.uregs->epsw &= ~EPSW_FE;
|
|
tsk->thread.fpu_flags &= ~THREAD_HAS_FPU;
|
|
}
|
|
#else /* !CONFIG_LAZY_SAVE_FPU */
|
|
if (fpu_state_owner == tsk) {
|
|
fpu_state_owner->thread.uregs->epsw &= ~EPSW_FE;
|
|
fpu_state_owner = NULL;
|
|
}
|
|
#endif /* !CONFIG_LAZY_SAVE_FPU */
|
|
|
|
preempt_enable();
|
|
|
|
/* we no longer have a valid current FPU state */
|
|
clear_using_fpu(tsk);
|
|
}
|
|
|
|
/*
|
|
* restore the FPU state from a signal context
|
|
*/
|
|
int fpu_restore_sigcontext(struct fpucontext *fpucontext)
|
|
{
|
|
struct task_struct *tsk = current;
|
|
int ret;
|
|
|
|
/* load up the old FPU state */
|
|
ret = copy_from_user(&tsk->thread.fpu_state, fpucontext,
|
|
min(sizeof(struct fpu_state_struct),
|
|
sizeof(struct fpucontext)));
|
|
if (!ret)
|
|
set_using_fpu(tsk);
|
|
|
|
return ret;
|
|
}
|
|
|
|
/*
|
|
* fill in the FPU structure for a core dump
|
|
*/
|
|
int dump_fpu(struct pt_regs *regs, elf_fpregset_t *fpreg)
|
|
{
|
|
struct task_struct *tsk = current;
|
|
int fpvalid;
|
|
|
|
fpvalid = is_using_fpu(tsk);
|
|
if (fpvalid) {
|
|
unlazy_fpu(tsk);
|
|
memcpy(fpreg, &tsk->thread.fpu_state, sizeof(*fpreg));
|
|
}
|
|
|
|
return fpvalid;
|
|
}
|