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/*
* 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(¤t->thread.fpsimd_state);
if (next->mm)
fpsimd_load_state(&next->thread.fpsimd_state);
}
void fpsimd_flush_thread(void)
{
memset(¤t->thread.fpsimd_state, 0, sizeof(struct fpsimd_state));
fpsimd_load_state(¤t->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(¤t->thread.fpsimd_state);
}
EXPORT_SYMBOL(kernel_neon_begin);
void kernel_neon_end(void)
{
if (current->mm)
fpsimd_load_state(¤t->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);
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