[deliverable/linux.git] / arch / mn10300 / kernel / fpu.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>

#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;
}
Commit	Line	Data
b920de1b DH	1	/* MN10300 FPU management
	2	*
	3	* Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
	4	* Written by David Howells (dhowells@redhat.com)
	5	*
	6	* This program is free software; you can redistribute it and/or
	7	* modify it under the terms of the GNU General Public Licence
	8	* as published by the Free Software Foundation; either version
	9	* 2 of the Licence, or (at your option) any later version.
	10	*/
	11	#include <asm/uaccess.h>
	12	#include <asm/fpu.h>
	13	#include <asm/elf.h>
	14	#include <asm/exceptions.h>
	15
278d91c4	16	#ifdef CONFIG_LAZY_SAVE_FPU
b920de1b	17	struct task_struct *fpu_state_owner;
278d91c4	18	#endif
b920de1b DH	19
b920de1b DH	20	/*
278d91c4	21	* error functions in FPU disabled exception
b920de1b	22	*/
278d91c4	23	asmlinkage void fpu_disabled_in_kernel(struct pt_regs *regs)
b920de1b	24	{
278d91c4 AT	25	die_if_no_fixup("An FPU Disabled exception happened in kernel space\n",
278d91c4 AT	26	regs, EXCEP_FPU_DISABLED);
b920de1b DH	27	}
	28
	29	/*
	30	* handle an FPU operational exception
	31	* - there's a possibility that if the FPU is asynchronous, the signal might
	32	* be meant for a process other than the current one
	33	*/
	34	asmlinkage void fpu_exception(struct pt_regs *regs, enum exception_code code)
	35	{
278d91c4	36	struct task_struct *tsk = current;
b920de1b	37	siginfo_t info;
278d91c4	38	u32 fpcr;
b920de1b DH	39
	40	if (!user_mode(regs))
	41	die_if_no_fixup("An FPU Operation exception happened in"
	42	" kernel space\n",
	43	regs, code);
	44
278d91c4	45	if (!is_using_fpu(tsk))
b920de1b DH	46	die_if_no_fixup("An FPU Operation exception happened,"
	47	" but the FPU is not in use",
	48	regs, code);
	49
	50	info.si_signo = SIGFPE;
	51	info.si_errno = 0;
	52	info.si_addr = (void *) tsk->thread.uregs->pc;
	53	info.si_code = FPE_FLTINV;
	54
278d91c4	55	unlazy_fpu(tsk);
b920de1b	56
278d91c4 AT	57	fpcr = tsk->thread.fpu_state.fpcr;
	58
	59	if (fpcr & FPCR_EC_Z)
	60	info.si_code = FPE_FLTDIV;
	61	else if (fpcr & FPCR_EC_O)
	62	info.si_code = FPE_FLTOVF;
	63	else if (fpcr & FPCR_EC_U)
	64	info.si_code = FPE_FLTUND;
	65	else if (fpcr & FPCR_EC_I)
	66	info.si_code = FPE_FLTRES;
b920de1b DH	67
	68	force_sig_info(SIGFPE, &info, tsk);
	69	}
	70
	71	/*
	72	* save the FPU state to a signal context
	73	*/
	74	int fpu_setup_sigcontext(struct fpucontext *fpucontext)
	75	{
b920de1b DH	76	struct task_struct *tsk = current;
	77
	78	if (!is_using_fpu(tsk))
	79	return 0;
	80
	81	/* transfer the current FPU state to memory and cause fpu_init() to be
	82	* triggered by the next attempted FPU operation by the current
	83	* process.
	84	*/
	85	preempt_disable();
	86
278d91c4 AT	87	#ifndef CONFIG_LAZY_SAVE_FPU
	88	if (tsk->thread.fpu_flags & THREAD_HAS_FPU) {
	89	fpu_save(&tsk->thread.fpu_state);
	90	tsk->thread.uregs->epsw &= ~EPSW_FE;
	91	tsk->thread.fpu_flags &= ~THREAD_HAS_FPU;
	92	}
	93	#else /* !CONFIG_LAZY_SAVE_FPU */
b920de1b DH	94	if (fpu_state_owner == tsk) {
	95	fpu_save(&tsk->thread.fpu_state);
	96	fpu_state_owner->thread.uregs->epsw &= ~EPSW_FE;
	97	fpu_state_owner = NULL;
	98	}
278d91c4	99	#endif /* !CONFIG_LAZY_SAVE_FPU */
b920de1b DH	100
	101	preempt_enable();
	102
	103	/* we no longer have a valid current FPU state */
	104	clear_using_fpu(tsk);
	105
	106	/* transfer the saved FPU state onto the userspace stack */
	107	if (copy_to_user(fpucontext,
	108	&tsk->thread.fpu_state,
	109	min(sizeof(struct fpu_state_struct),
	110	sizeof(struct fpucontext))))
	111	return -1;
	112
	113	return 1;
b920de1b DH	114	}
	115
	116	/*
	117	* kill a process's FPU state during restoration after signal handling
	118	*/
	119	void fpu_kill_state(struct task_struct *tsk)
	120	{
b920de1b DH	121	/* disown anything left in the FPU */
	122	preempt_disable();
	123
278d91c4 AT	124	#ifndef CONFIG_LAZY_SAVE_FPU
	125	if (tsk->thread.fpu_flags & THREAD_HAS_FPU) {
	126	tsk->thread.uregs->epsw &= ~EPSW_FE;
	127	tsk->thread.fpu_flags &= ~THREAD_HAS_FPU;
	128	}
	129	#else /* !CONFIG_LAZY_SAVE_FPU */
b920de1b DH	130	if (fpu_state_owner == tsk) {
	131	fpu_state_owner->thread.uregs->epsw &= ~EPSW_FE;
	132	fpu_state_owner = NULL;
	133	}
278d91c4	134	#endif /* !CONFIG_LAZY_SAVE_FPU */
b920de1b DH	135
b920de1b DH	136	preempt_enable();
278d91c4	137
b920de1b DH	138	/* we no longer have a valid current FPU state */
	139	clear_using_fpu(tsk);
	140	}
	141
	142	/*
	143	* restore the FPU state from a signal context
	144	*/
	145	int fpu_restore_sigcontext(struct fpucontext *fpucontext)
	146	{
	147	struct task_struct *tsk = current;
	148	int ret;
	149
	150	/* load up the old FPU state */
278d91c4	151	ret = copy_from_user(&tsk->thread.fpu_state, fpucontext,
b920de1b DH	152	min(sizeof(struct fpu_state_struct),
	153	sizeof(struct fpucontext)));
	154	if (!ret)
	155	set_using_fpu(tsk);
	156
	157	return ret;
	158	}
	159
	160	/*
	161	* fill in the FPU structure for a core dump
	162	*/
	163	int dump_fpu(struct pt_regs regs, elf_fpregset_t fpreg)
	164	{
	165	struct task_struct *tsk = current;
	166	int fpvalid;
	167
	168	fpvalid = is_using_fpu(tsk);
	169	if (fpvalid) {
	170	unlazy_fpu(tsk);
	171	memcpy(fpreg, &tsk->thread.fpu_state, sizeof(*fpreg));
	172	}
	173
	174	return fpvalid;
	175	}