arm64: Floating point and SIMD
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>
This commit is contained in:
parent
3dd681d944
commit
53631b54c8
64
arch/arm64/include/asm/fpsimd.h
Normal file
64
arch/arm64/include/asm/fpsimd.h
Normal file
|
@ -0,0 +1,64 @@
|
|||
/*
|
||||
* Copyright (C) 2012 ARM Ltd.
|
||||
*
|
||||
* 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/>.
|
||||
*/
|
||||
#ifndef __ASM_FP_H
|
||||
#define __ASM_FP_H
|
||||
|
||||
#include <asm/ptrace.h>
|
||||
|
||||
#ifndef __ASSEMBLY__
|
||||
|
||||
/*
|
||||
* FP/SIMD storage area has:
|
||||
* - FPSR and FPCR
|
||||
* - 32 128-bit data registers
|
||||
*
|
||||
* Note that user_fp forms a prefix of this structure, which is relied
|
||||
* upon in the ptrace FP/SIMD accessors. struct user_fpsimd_state must
|
||||
* form a prefix of struct fpsimd_state.
|
||||
*/
|
||||
struct fpsimd_state {
|
||||
union {
|
||||
struct user_fpsimd_state user_fpsimd;
|
||||
struct {
|
||||
__uint128_t vregs[32];
|
||||
u32 fpsr;
|
||||
u32 fpcr;
|
||||
};
|
||||
};
|
||||
};
|
||||
|
||||
#if defined(__KERNEL__) && defined(CONFIG_COMPAT)
|
||||
/* Masks for extracting the FPSR and FPCR from the FPSCR */
|
||||
#define VFP_FPSCR_STAT_MASK 0xf800009f
|
||||
#define VFP_FPSCR_CTRL_MASK 0x07f79f00
|
||||
/*
|
||||
* The VFP state has 32x64-bit registers and a single 32-bit
|
||||
* control/status register.
|
||||
*/
|
||||
#define VFP_STATE_SIZE ((32 * 8) + 4)
|
||||
#endif
|
||||
|
||||
struct task_struct;
|
||||
|
||||
extern void fpsimd_save_state(struct fpsimd_state *state);
|
||||
extern void fpsimd_load_state(struct fpsimd_state *state);
|
||||
|
||||
extern void fpsimd_thread_switch(struct task_struct *next);
|
||||
extern void fpsimd_flush_thread(void);
|
||||
|
||||
#endif
|
||||
|
||||
#endif
|
80
arch/arm64/kernel/entry-fpsimd.S
Normal file
80
arch/arm64/kernel/entry-fpsimd.S
Normal file
|
@ -0,0 +1,80 @@
|
|||
/*
|
||||
* FP/SIMD state saving and restoring
|
||||
*
|
||||
* 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/linkage.h>
|
||||
|
||||
#include <asm/assembler.h>
|
||||
|
||||
/*
|
||||
* Save the FP registers.
|
||||
*
|
||||
* x0 - pointer to struct fpsimd_state
|
||||
*/
|
||||
ENTRY(fpsimd_save_state)
|
||||
stp q0, q1, [x0, #16 * 0]
|
||||
stp q2, q3, [x0, #16 * 2]
|
||||
stp q4, q5, [x0, #16 * 4]
|
||||
stp q6, q7, [x0, #16 * 6]
|
||||
stp q8, q9, [x0, #16 * 8]
|
||||
stp q10, q11, [x0, #16 * 10]
|
||||
stp q12, q13, [x0, #16 * 12]
|
||||
stp q14, q15, [x0, #16 * 14]
|
||||
stp q16, q17, [x0, #16 * 16]
|
||||
stp q18, q19, [x0, #16 * 18]
|
||||
stp q20, q21, [x0, #16 * 20]
|
||||
stp q22, q23, [x0, #16 * 22]
|
||||
stp q24, q25, [x0, #16 * 24]
|
||||
stp q26, q27, [x0, #16 * 26]
|
||||
stp q28, q29, [x0, #16 * 28]
|
||||
stp q30, q31, [x0, #16 * 30]!
|
||||
mrs x8, fpsr
|
||||
str w8, [x0, #16 * 2]
|
||||
mrs x8, fpcr
|
||||
str w8, [x0, #16 * 2 + 4]
|
||||
ret
|
||||
ENDPROC(fpsimd_save_state)
|
||||
|
||||
/*
|
||||
* Load the FP registers.
|
||||
*
|
||||
* x0 - pointer to struct fpsimd_state
|
||||
*/
|
||||
ENTRY(fpsimd_load_state)
|
||||
ldp q0, q1, [x0, #16 * 0]
|
||||
ldp q2, q3, [x0, #16 * 2]
|
||||
ldp q4, q5, [x0, #16 * 4]
|
||||
ldp q6, q7, [x0, #16 * 6]
|
||||
ldp q8, q9, [x0, #16 * 8]
|
||||
ldp q10, q11, [x0, #16 * 10]
|
||||
ldp q12, q13, [x0, #16 * 12]
|
||||
ldp q14, q15, [x0, #16 * 14]
|
||||
ldp q16, q17, [x0, #16 * 16]
|
||||
ldp q18, q19, [x0, #16 * 18]
|
||||
ldp q20, q21, [x0, #16 * 20]
|
||||
ldp q22, q23, [x0, #16 * 22]
|
||||
ldp q24, q25, [x0, #16 * 24]
|
||||
ldp q26, q27, [x0, #16 * 26]
|
||||
ldp q28, q29, [x0, #16 * 28]
|
||||
ldp q30, q31, [x0, #16 * 30]!
|
||||
ldr w8, [x0, #16 * 2]
|
||||
ldr w9, [x0, #16 * 2 + 4]
|
||||
msr fpsr, x8
|
||||
msr fpcr, x9
|
||||
ret
|
||||
ENDPROC(fpsimd_load_state)
|
106
arch/arm64/kernel/fpsimd.c
Normal file
106
arch/arm64/kernel/fpsimd.c
Normal file
|
@ -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);
|
Loading…
Reference in a new issue