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Diffstat (limited to 'arch/arm64/kernel/fpsimd.c')
| -rw-r--r-- | arch/arm64/kernel/fpsimd.c | 106 |
1 files changed, 106 insertions, 0 deletions
diff --git a/arch/arm64/kernel/fpsimd.c b/arch/arm64/kernel/fpsimd.c new file mode 100644 index 000000000000..e8b8357aedb4 --- /dev/null +++ b/arch/arm64/kernel/fpsimd.c @@ -0,0 +1,106 @@ +/* + * 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 <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); +} + +/* + * 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); |