mirror of
https://github.com/AuxXxilium/linux_dsm_epyc7002.git
synced 2024-12-14 17:06:39 +07:00
53631b54c8
This patch adds support for FP/ASIMD register bank saving and restoring during context switch and FP exception handling to generate SIGFPE. There are 32 128-bit registers and the context switching is currently done non-lazily. Benchmarks on real hardware are required before implementing lazy FP state saving/restoring. Signed-off-by: Will Deacon <will.deacon@arm.com> Signed-off-by: Catalin Marinas <catalin.marinas@arm.com> Acked-by: Tony Lindgren <tony@atomide.com> Acked-by: Arnd Bergmann <arnd@arndb.de> Acked-by: Nicolas Pitre <nico@linaro.org> Acked-by: Olof Johansson <olof@lixom.net> Acked-by: Santosh Shilimkar <santosh.shilimkar@ti.com>
107 lines
2.5 KiB
C
107 lines
2.5 KiB
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 <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);
|