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