[deliverable/linux.git] / arch / arm64 / kernel / fpsimd.c

/*
 * FP/SIMD context switching and fault handling
 *
 * Copyright (C) 2012 ARM Ltd.
 * Author: Catalin Marinas <catalin.marinas@arm.com>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */

#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/sched.h>
#include <linux/signal.h>
#include <linux/hardirq.h>

#include <asm/fpsimd.h>
#include <asm/cputype.h>

#define FPEXC_IOF	(1 << 0)
#define FPEXC_DZF	(1 << 1)
#define FPEXC_OFF	(1 << 2)
#define FPEXC_UFF	(1 << 3)
#define FPEXC_IXF	(1 << 4)
#define FPEXC_IDF	(1 << 7)

/*
 * Trapped FP/ASIMD access.
 */
void do_fpsimd_acc(unsigned int esr, struct pt_regs *regs)
{
	/* TODO: implement lazy context saving/restoring */
	WARN_ON(1);
}

/*
 * Raise a SIGFPE for the current process.
 */
void do_fpsimd_exc(unsigned int esr, struct pt_regs *regs)
{
	siginfo_t info;
	unsigned int si_code = 0;

	if (esr & FPEXC_IOF)
		si_code = FPE_FLTINV;
	else if (esr & FPEXC_DZF)
		si_code = FPE_FLTDIV;
	else if (esr & FPEXC_OFF)
		si_code = FPE_FLTOVF;
	else if (esr & FPEXC_UFF)
		si_code = FPE_FLTUND;
	else if (esr & FPEXC_IXF)
		si_code = FPE_FLTRES;

	memset(&info, 0, sizeof(info));
	info.si_signo = SIGFPE;
	info.si_code = si_code;
	info.si_addr = (void __user *)instruction_pointer(regs);

	send_sig_info(SIGFPE, &info, current);
}

void fpsimd_thread_switch(struct task_struct *next)
{
	/* check if not kernel threads */
	if (current->mm)
		fpsimd_save_state(&current->thread.fpsimd_state);
	if (next->mm)
		fpsimd_load_state(&next->thread.fpsimd_state);
}

void fpsimd_flush_thread(void)
{
	memset(&current->thread.fpsimd_state, 0, sizeof(struct fpsimd_state));
	fpsimd_load_state(&current->thread.fpsimd_state);
}

#ifdef CONFIG_KERNEL_MODE_NEON

/*
 * Kernel-side NEON support functions
 */
void kernel_neon_begin(void)
{
	/* Avoid using the NEON in interrupt context */
	BUG_ON(in_interrupt());
	preempt_disable();

	if (current->mm)
		fpsimd_save_state(&current->thread.fpsimd_state);
}
EXPORT_SYMBOL(kernel_neon_begin);

void kernel_neon_end(void)
{
	if (current->mm)
		fpsimd_load_state(&current->thread.fpsimd_state);

	preempt_enable();
}
EXPORT_SYMBOL(kernel_neon_end);

#endif /* CONFIG_KERNEL_MODE_NEON */

/*
 * FP/SIMD support code initialisation.
 */
static int __init fpsimd_init(void)
{
	u64 pfr = read_cpuid(ID_AA64PFR0_EL1);

	if (pfr & (0xf << 16)) {
		pr_notice("Floating-point is not implemented\n");
		return 0;
	}
	elf_hwcap |= HWCAP_FP;

	if (pfr & (0xf << 20))
		pr_notice("Advanced SIMD is not implemented\n");
	else
		elf_hwcap |= HWCAP_ASIMD;

	return 0;
}
late_initcall(fpsimd_init);
Commit	Line	Data
53631b54 CM	1	/*
	2	* FP/SIMD context switching and fault handling
	3	*
	4	* Copyright (C) 2012 ARM Ltd.
	5	* Author: Catalin Marinas <catalin.marinas@arm.com>
	6	*
	7	* This program is free software; you can redistribute it and/or modify
	8	* it under the terms of the GNU General Public License version 2 as
	9	* published by the Free Software Foundation.
	10	*
	11	* This program is distributed in the hope that it will be useful,
	12	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	13	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	14	* GNU General Public License for more details.
	15	*
	16	* You should have received a copy of the GNU General Public License
	17	* along with this program. If not, see <http://www.gnu.org/licenses/>.
	18	*/
	19
	20	#include <linux/kernel.h>
	21	#include <linux/init.h>
	22	#include <linux/sched.h>
	23	#include <linux/signal.h>
4cfb3613	24	#include <linux/hardirq.h>
53631b54 CM	25
	26	#include <asm/fpsimd.h>
	27	#include <asm/cputype.h>
	28
	29	#define FPEXC_IOF (1 << 0)
	30	#define FPEXC_DZF (1 << 1)
	31	#define FPEXC_OFF (1 << 2)
	32	#define FPEXC_UFF (1 << 3)
	33	#define FPEXC_IXF (1 << 4)
	34	#define FPEXC_IDF (1 << 7)
	35
	36	/*
	37	* Trapped FP/ASIMD access.
	38	*/
	39	void do_fpsimd_acc(unsigned int esr, struct pt_regs *regs)
	40	{
	41	/* TODO: implement lazy context saving/restoring */
	42	WARN_ON(1);
	43	}
	44
	45	/*
	46	* Raise a SIGFPE for the current process.
	47	*/
	48	void do_fpsimd_exc(unsigned int esr, struct pt_regs *regs)
	49	{
	50	siginfo_t info;
	51	unsigned int si_code = 0;
	52
	53	if (esr & FPEXC_IOF)
	54	si_code = FPE_FLTINV;
	55	else if (esr & FPEXC_DZF)
	56	si_code = FPE_FLTDIV;
	57	else if (esr & FPEXC_OFF)
	58	si_code = FPE_FLTOVF;
	59	else if (esr & FPEXC_UFF)
	60	si_code = FPE_FLTUND;
	61	else if (esr & FPEXC_IXF)
	62	si_code = FPE_FLTRES;
	63
	64	memset(&info, 0, sizeof(info));
	65	info.si_signo = SIGFPE;
	66	info.si_code = si_code;
	67	info.si_addr = (void __user *)instruction_pointer(regs);
	68
	69	send_sig_info(SIGFPE, &info, current);
	70	}
	71
	72	void fpsimd_thread_switch(struct task_struct *next)
	73	{
	74	/* check if not kernel threads */
	75	if (current->mm)
	76	fpsimd_save_state(&current->thread.fpsimd_state);
	77	if (next->mm)
	78	fpsimd_load_state(&next->thread.fpsimd_state);
	79	}
	80
	81	void fpsimd_flush_thread(void)
	82	{
	83	memset(&current->thread.fpsimd_state, 0, sizeof(struct fpsimd_state));
	84	fpsimd_load_state(&current->thread.fpsimd_state);
	85	}
	86
4cfb3613 AB	87	#ifdef CONFIG_KERNEL_MODE_NEON
	88
	89	/*
	90	* Kernel-side NEON support functions
	91	*/
	92	void kernel_neon_begin(void)
	93	{
	94	/* Avoid using the NEON in interrupt context */
	95	BUG_ON(in_interrupt());
	96	preempt_disable();
	97
	98	if (current->mm)
	99	fpsimd_save_state(&current->thread.fpsimd_state);
	100	}
	101	EXPORT_SYMBOL(kernel_neon_begin);
	102
	103	void kernel_neon_end(void)
	104	{
	105	if (current->mm)
	106	fpsimd_load_state(&current->thread.fpsimd_state);
	107
	108	preempt_enable();
	109	}
	110	EXPORT_SYMBOL(kernel_neon_end);
	111
	112	#endif /* CONFIG_KERNEL_MODE_NEON */
	113
53631b54 CM	114	/*
	115	* FP/SIMD support code initialisation.
	116	*/
	117	static int __init fpsimd_init(void)
	118	{
	119	u64 pfr = read_cpuid(ID_AA64PFR0_EL1);
	120
	121	if (pfr & (0xf << 16)) {
	122	pr_notice("Floating-point is not implemented\n");
	123	return 0;
	124	}
	125	elf_hwcap \|= HWCAP_FP;
	126
	127	if (pfr & (0xf << 20))
	128	pr_notice("Advanced SIMD is not implemented\n");
	129	else
	130	elf_hwcap \|= HWCAP_ASIMD;
	131
	132	return 0;
	133	}
	134	late_initcall(fpsimd_init);