From: Guo Ren <guo...@linux.alibaba.com> This patch adds task switch support for vector. It supports lazy save and restore mechanism. It also supports all lengths of vlen.
[greentime...@sifive.com: add support for dynamic vlen, fix __vstate_clean() and lazy save/restore bug] [nick.kni...@sifive.com: Rewrite vector.S to support dynamic vlen, xlen and code refine] Signed-off-by: Nick Knight <nick.kni...@sifive.com> Signed-off-by: Greentime Hu <greentime...@sifive.com> Signed-off-by: Guo Ren <guo...@linux.alibaba.com> --- arch/riscv/include/asm/switch_to.h | 71 +++++++++++++++++++++++++ arch/riscv/kernel/Makefile | 1 + arch/riscv/kernel/process.c | 40 ++++++++++++++ arch/riscv/kernel/vector.S | 84 ++++++++++++++++++++++++++++++ 4 files changed, 196 insertions(+) create mode 100644 arch/riscv/kernel/vector.S diff --git a/arch/riscv/include/asm/switch_to.h b/arch/riscv/include/asm/switch_to.h index b9234e7178d0..a047dd75e09d 100644 --- a/arch/riscv/include/asm/switch_to.h +++ b/arch/riscv/include/asm/switch_to.h @@ -6,10 +6,12 @@ #ifndef _ASM_RISCV_SWITCH_TO_H #define _ASM_RISCV_SWITCH_TO_H +#include <linux/slab.h> #include <linux/sched/task_stack.h> #include <asm/processor.h> #include <asm/ptrace.h> #include <asm/csr.h> +#include <asm/asm-offsets.h> #ifdef CONFIG_FPU extern void __fstate_save(struct task_struct *save_to); @@ -63,6 +65,73 @@ extern bool has_fpu; #define __switch_to_fpu(__prev, __next) do { } while (0) #endif +#ifdef CONFIG_VECTOR +extern bool has_vector; +extern unsigned long riscv_vsize; +extern void __vstate_save(struct __riscv_v_state *save_to, void *datap); +extern void __vstate_restore(struct __riscv_v_state *restore_from, void *datap); + +static inline void __vstate_clean(struct pt_regs *regs) +{ + regs->status = (regs->status & ~(SR_VS)) | SR_VS_CLEAN; +} + +static inline void vstate_off(struct task_struct *task, + struct pt_regs *regs) +{ + regs->status = (regs->status & ~SR_VS) | SR_VS_OFF; +} + +static inline void vstate_save(struct task_struct *task, + struct pt_regs *regs) +{ + if ((regs->status & SR_VS) == SR_VS_DIRTY) { + struct __riscv_v_state *vstate = &(task->thread.vstate); + + /* Allocate space for vector registers. */ + if (!vstate->datap) { + vstate->datap = kzalloc(riscv_vsize, GFP_KERNEL); + vstate->size = riscv_vsize; + } + __vstate_save(vstate, vstate->datap); + __vstate_clean(regs); + } +} + +static inline void vstate_restore(struct task_struct *task, + struct pt_regs *regs) +{ + if ((regs->status & SR_VS) != SR_VS_OFF) { + struct __riscv_v_state *vstate = &(task->thread.vstate); + + /* Allocate space for vector registers. */ + if (!vstate->datap) { + vstate->datap = kzalloc(riscv_vsize, GFP_KERNEL); + vstate->size = riscv_vsize; + } + __vstate_restore(vstate, vstate->datap); + __vstate_clean(regs); + } +} + +static inline void __switch_to_vector(struct task_struct *prev, + struct task_struct *next) +{ + struct pt_regs *regs; + + regs = task_pt_regs(prev); + if (unlikely(regs->status & SR_SD)) + vstate_save(prev, regs); + vstate_restore(next, task_pt_regs(next)); +} + +#else +#define has_vector false +#define vstate_save(task, regs) do { } while (0) +#define vstate_restore(task, regs) do { } while (0) +#define __switch_to_vector(__prev, __next) do { } while (0) +#endif + extern struct task_struct *__switch_to(struct task_struct *, struct task_struct *); @@ -72,6 +141,8 @@ do { \ struct task_struct *__next = (next); \ if (has_fpu) \ __switch_to_fpu(__prev, __next); \ + if (has_vector) \ + __switch_to_vector(__prev, __next); \ ((last) = __switch_to(__prev, __next)); \ } while (0) diff --git a/arch/riscv/kernel/Makefile b/arch/riscv/kernel/Makefile index 86c83081044f..dee489a1a526 100644 --- a/arch/riscv/kernel/Makefile +++ b/arch/riscv/kernel/Makefile @@ -33,6 +33,7 @@ obj-$(CONFIG_MMU) += vdso.o vdso/ obj-$(CONFIG_RISCV_M_MODE) += clint.o traps_misaligned.o obj-$(CONFIG_FPU) += fpu.o +obj-$(CONFIG_VECTOR) += vector.o obj-$(CONFIG_SMP) += smpboot.o obj-$(CONFIG_SMP) += smp.o obj-$(CONFIG_SMP) += cpu_ops.o diff --git a/arch/riscv/kernel/process.c b/arch/riscv/kernel/process.c index 610c11e91606..fc8761c04e9f 100644 --- a/arch/riscv/kernel/process.c +++ b/arch/riscv/kernel/process.c @@ -76,6 +76,16 @@ void start_thread(struct pt_regs *regs, unsigned long pc, */ fstate_restore(current, regs); } + + if (has_vector) { + regs->status |= SR_VS_INITIAL; + /* + * Restore the initial value to the vector register + * before starting the user program. + */ + vstate_restore(current, regs); + } + regs->epc = pc; regs->sp = sp; set_fs(USER_DS); @@ -92,15 +102,45 @@ void flush_thread(void) fstate_off(current, task_pt_regs(current)); memset(¤t->thread.fstate, 0, sizeof(current->thread.fstate)); #endif +#ifdef CONFIG_VECTOR + /* Reset vector state */ + vstate_off(current, task_pt_regs(current)); + memset(¤t->thread.vstate, 0, sizeof(current->thread.vstate)); +#endif } int arch_dup_task_struct(struct task_struct *dst, struct task_struct *src) { fstate_save(src, task_pt_regs(src)); + if (has_vector) + /* To make sure every dirty vector context is saved. */ + vstate_save(src, task_pt_regs(src)); *dst = *src; + if (has_vector) { + /* Copy vector context to the forked task from parent. */ + if ((task_pt_regs(src)->status & SR_VS) != SR_VS_OFF) { + unsigned long size = src->thread.vstate.size; + + dst->thread.vstate.datap = kzalloc(size, GFP_KERNEL); + /* Failed to allocate memory. */ + if (!dst->thread.vstate.datap) + return -ENOMEM; + /* Copy the src vector context to dst. */ + memcpy(dst->thread.vstate.datap, + src->thread.vstate.datap, size); + } + } + return 0; } +void arch_release_task_struct(struct task_struct *tsk) +{ + /* Free the vector context of datap. */ + if (has_vector) + kfree(tsk->thread.vstate.datap); +} + int copy_thread_tls(unsigned long clone_flags, unsigned long usp, unsigned long arg, struct task_struct *p, unsigned long tls) { diff --git a/arch/riscv/kernel/vector.S b/arch/riscv/kernel/vector.S new file mode 100644 index 000000000000..91d5dd29cd0f --- /dev/null +++ b/arch/riscv/kernel/vector.S @@ -0,0 +1,84 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/* + * Copyright (C) 2012 Regents of the University of California + * Copyright (C) 2017 SiFive + * Copyright (C) 2019 Alibaba Group Holding Limited + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License + * as published by the Free Software Foundation, version 2. + * + * 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. + */ + +#include <linux/linkage.h> + +#include <asm/asm.h> +#include <asm/csr.h> +#include <asm/asm-offsets.h> + +#define vstatep a0 +#define datap a1 +#define x_vstart t0 +#define x_vtype t1 +#define x_vl t2 +#define x_vcsr t3 +#define incr t4 +#define m_one t5 +#define status t6 + +ENTRY(__vstate_save) + li status, SR_VS + csrs sstatus, status + + csrr x_vstart, CSR_VSTART + csrr x_vtype, CSR_VTYPE + csrr x_vl, CSR_VL + csrr x_vcsr, CSR_VCSR + li m_one, -1 + vsetvli incr, m_one, e8, m8 + vse.v v0, (datap) + add datap, datap, incr + vse.v v8, (datap) + add datap, datap, incr + vse.v v16, (datap) + add datap, datap, incr + vse.v v24, (datap) + + REG_S x_vstart, RISCV_V_STATE_VSTART(vstatep) + REG_S x_vtype, RISCV_V_STATE_VTYPE(vstatep) + REG_S x_vl, RISCV_V_STATE_VL(vstatep) + REG_S x_vcsr, RISCV_V_STATE_VCSR(vstatep) + + csrc sstatus, status + ret +ENDPROC(__vstate_save) + +ENTRY(__vstate_restore) + li status, SR_VS + csrs sstatus, status + + li m_one, -1 + vsetvli incr, m_one, e8, m8 + vle.v v0, (datap) + add datap, datap, incr + vle.v v8, (datap) + add datap, datap, incr + vle.v v16, (datap) + add datap, datap, incr + vle.v v24, (datap) + + REG_L x_vstart, RISCV_V_STATE_VSTART(vstatep) + REG_L x_vtype, RISCV_V_STATE_VTYPE(vstatep) + REG_L x_vl, RISCV_V_STATE_VL(vstatep) + REG_L x_vcsr, RISCV_V_STATE_VCSR(vstatep) + vsetvl x0, x_vl, x_vtype + csrw CSR_VSTART, x_vstart + csrw CSR_VCSR, x_vcsr + + csrc sstatus, status + ret +ENDPROC(__vstate_restore) -- 2.26.2