diff options
Diffstat (limited to 'arch/riscv/kernel')
| -rw-r--r-- | arch/riscv/kernel/entry.S | 8 | ||||
| -rw-r--r-- | arch/riscv/kernel/kernel_mode_vector.c | 133 | ||||
| -rw-r--r-- | arch/riscv/kernel/process.c | 3 | ||||
| -rw-r--r-- | arch/riscv/kernel/vector.c | 31 |
4 files changed, 163 insertions, 12 deletions
diff --git a/arch/riscv/kernel/entry.S b/arch/riscv/kernel/entry.S index 54ca4564a926..9d1a305d5508 100644 --- a/arch/riscv/kernel/entry.S +++ b/arch/riscv/kernel/entry.S @@ -83,6 +83,10 @@ SYM_CODE_START(handle_exception) /* Load the kernel shadow call stack pointer if coming from userspace */ scs_load_current_if_task_changed s5 +#ifdef CONFIG_RISCV_ISA_V_PREEMPTIVE + move a0, sp + call riscv_v_context_nesting_start +#endif move a0, sp /* pt_regs */ la ra, ret_from_exception @@ -138,6 +142,10 @@ SYM_CODE_START_NOALIGN(ret_from_exception) */ csrw CSR_SCRATCH, tp 1: +#ifdef CONFIG_RISCV_ISA_V_PREEMPTIVE + move a0, sp + call riscv_v_context_nesting_end +#endif REG_L a0, PT_STATUS(sp) /* * The current load reservation is effectively part of the processor's diff --git a/arch/riscv/kernel/kernel_mode_vector.c b/arch/riscv/kernel/kernel_mode_vector.c index 241a8f834e1c..6afe80c7f03a 100644 --- a/arch/riscv/kernel/kernel_mode_vector.c +++ b/arch/riscv/kernel/kernel_mode_vector.c @@ -14,10 +14,13 @@ #include <asm/vector.h> #include <asm/switch_to.h> #include <asm/simd.h> +#ifdef CONFIG_RISCV_ISA_V_PREEMPTIVE +#include <asm/asm-prototypes.h> +#endif static inline void riscv_v_flags_set(u32 flags) { - current->thread.riscv_v_flags = flags; + WRITE_ONCE(current->thread.riscv_v_flags, flags); } static inline void riscv_v_start(u32 flags) @@ -27,12 +30,14 @@ static inline void riscv_v_start(u32 flags) orig = riscv_v_flags(); BUG_ON((orig & flags) != 0); riscv_v_flags_set(orig | flags); + barrier(); } static inline void riscv_v_stop(u32 flags) { int orig; + barrier(); orig = riscv_v_flags(); BUG_ON((orig & flags) == 0); riscv_v_flags_set(orig & ~flags); @@ -75,6 +80,117 @@ void put_cpu_vector_context(void) preempt_enable(); } +#ifdef CONFIG_RISCV_ISA_V_PREEMPTIVE +static __always_inline u32 *riscv_v_flags_ptr(void) +{ + return ¤t->thread.riscv_v_flags; +} + +static inline void riscv_preempt_v_set_dirty(void) +{ + *riscv_v_flags_ptr() |= RISCV_PREEMPT_V_DIRTY; +} + +static inline void riscv_preempt_v_reset_flags(void) +{ + *riscv_v_flags_ptr() &= ~(RISCV_PREEMPT_V_DIRTY | RISCV_PREEMPT_V_NEED_RESTORE); +} + +static inline void riscv_v_ctx_depth_inc(void) +{ + *riscv_v_flags_ptr() += RISCV_V_CTX_UNIT_DEPTH; +} + +static inline void riscv_v_ctx_depth_dec(void) +{ + *riscv_v_flags_ptr() -= RISCV_V_CTX_UNIT_DEPTH; +} + +static inline u32 riscv_v_ctx_get_depth(void) +{ + return *riscv_v_flags_ptr() & RISCV_V_CTX_DEPTH_MASK; +} + +static int riscv_v_stop_kernel_context(void) +{ + if (riscv_v_ctx_get_depth() != 0 || !riscv_preempt_v_started(current)) + return 1; + + riscv_preempt_v_clear_dirty(current); + riscv_v_stop(RISCV_PREEMPT_V); + return 0; +} + +static int riscv_v_start_kernel_context(bool *is_nested) +{ + struct __riscv_v_ext_state *kvstate, *uvstate; + + kvstate = ¤t->thread.kernel_vstate; + if (!kvstate->datap) + return -ENOENT; + + if (riscv_preempt_v_started(current)) { + WARN_ON(riscv_v_ctx_get_depth() == 0); + *is_nested = true; + get_cpu_vector_context(); + if (riscv_preempt_v_dirty(current)) { + __riscv_v_vstate_save(kvstate, kvstate->datap); + riscv_preempt_v_clear_dirty(current); + } + riscv_preempt_v_set_restore(current); + return 0; + } + + /* Transfer the ownership of V from user to kernel, then save */ + riscv_v_start(RISCV_PREEMPT_V | RISCV_PREEMPT_V_DIRTY); + if ((task_pt_regs(current)->status & SR_VS) == SR_VS_DIRTY) { + uvstate = ¤t->thread.vstate; + __riscv_v_vstate_save(uvstate, uvstate->datap); + } + riscv_preempt_v_clear_dirty(current); + return 0; +} + +/* low-level V context handling code, called with irq disabled */ +asmlinkage void riscv_v_context_nesting_start(struct pt_regs *regs) +{ + int depth; + + if (!riscv_preempt_v_started(current)) + return; + + depth = riscv_v_ctx_get_depth(); + if (depth == 0 && (regs->status & SR_VS) == SR_VS_DIRTY) + riscv_preempt_v_set_dirty(); + + riscv_v_ctx_depth_inc(); +} + +asmlinkage void riscv_v_context_nesting_end(struct pt_regs *regs) +{ + struct __riscv_v_ext_state *vstate = ¤t->thread.kernel_vstate; + u32 depth; + + WARN_ON(!irqs_disabled()); + + if (!riscv_preempt_v_started(current)) + return; + + riscv_v_ctx_depth_dec(); + depth = riscv_v_ctx_get_depth(); + if (depth == 0) { + if (riscv_preempt_v_restore(current)) { + __riscv_v_vstate_restore(vstate, vstate->datap); + __riscv_v_vstate_clean(regs); + riscv_preempt_v_reset_flags(); + } + } +} +#else +#define riscv_v_start_kernel_context(nested) (-ENOENT) +#define riscv_v_stop_kernel_context() (-ENOENT) +#endif /* CONFIG_RISCV_ISA_V_PREEMPTIVE */ + /* * kernel_vector_begin(): obtain the CPU vector registers for use by the calling * context @@ -90,14 +206,20 @@ void put_cpu_vector_context(void) */ void kernel_vector_begin(void) { + bool nested = false; + if (WARN_ON(!has_vector())) return; BUG_ON(!may_use_simd()); - get_cpu_vector_context(); + if (riscv_v_start_kernel_context(&nested)) { + get_cpu_vector_context(); + riscv_v_vstate_save(¤t->thread.vstate, task_pt_regs(current)); + } - riscv_v_vstate_save(¤t->thread.vstate, task_pt_regs(current)); + if (!nested) + riscv_v_vstate_set_restore(current, task_pt_regs(current)); riscv_v_enable(); } @@ -117,10 +239,9 @@ void kernel_vector_end(void) if (WARN_ON(!has_vector())) return; - riscv_v_vstate_set_restore(current, task_pt_regs(current)); - riscv_v_disable(); - put_cpu_vector_context(); + if (riscv_v_stop_kernel_context()) + put_cpu_vector_context(); } EXPORT_SYMBOL_GPL(kernel_vector_end); diff --git a/arch/riscv/kernel/process.c b/arch/riscv/kernel/process.c index 862d59c3872e..92922dbd5b5c 100644 --- a/arch/riscv/kernel/process.c +++ b/arch/riscv/kernel/process.c @@ -188,6 +188,7 @@ int arch_dup_task_struct(struct task_struct *dst, struct task_struct *src) *dst = *src; /* clear entire V context, including datap for a new task */ memset(&dst->thread.vstate, 0, sizeof(struct __riscv_v_ext_state)); + memset(&dst->thread.kernel_vstate, 0, sizeof(struct __riscv_v_ext_state)); clear_tsk_thread_flag(dst, TIF_RISCV_V_DEFER_RESTORE); return 0; @@ -224,6 +225,8 @@ int copy_thread(struct task_struct *p, const struct kernel_clone_args *args) p->thread.s[0] = 0; } p->thread.riscv_v_flags = 0; + if (has_vector()) + riscv_v_thread_alloc(p); p->thread.ra = (unsigned long)ret_from_fork; p->thread.sp = (unsigned long)childregs; /* kernel sp */ return 0; diff --git a/arch/riscv/kernel/vector.c b/arch/riscv/kernel/vector.c index f7b4aeb9e457..6727d1d3b8f2 100644 --- a/arch/riscv/kernel/vector.c +++ b/arch/riscv/kernel/vector.c @@ -22,6 +22,9 @@ static bool riscv_v_implicit_uacc = IS_ENABLED(CONFIG_RISCV_ISA_V_DEFAULT_ENABLE); static struct kmem_cache *riscv_v_user_cachep; +#ifdef CONFIG_RISCV_ISA_V_PREEMPTIVE +static struct kmem_cache *riscv_v_kernel_cachep; +#endif unsigned long riscv_v_vsize __read_mostly; EXPORT_SYMBOL_GPL(riscv_v_vsize); @@ -56,6 +59,11 @@ void __init riscv_v_setup_ctx_cache(void) riscv_v_user_cachep = kmem_cache_create_usercopy("riscv_vector_ctx", riscv_v_vsize, 16, SLAB_PANIC, 0, riscv_v_vsize, NULL); +#ifdef CONFIG_RISCV_ISA_V_PREEMPTIVE + riscv_v_kernel_cachep = kmem_cache_create("riscv_vector_kctx", + riscv_v_vsize, 16, + SLAB_PANIC, NULL); +#endif } static bool insn_is_vector(u32 insn_buf) @@ -91,24 +99,35 @@ static bool insn_is_vector(u32 insn_buf) return false; } -static int riscv_v_thread_zalloc(void) +static int riscv_v_thread_zalloc(struct kmem_cache *cache, + struct __riscv_v_ext_state *ctx) { void *datap; - datap = kmem_cache_zalloc(riscv_v_user_cachep, GFP_KERNEL); + datap = kmem_cache_zalloc(cache, GFP_KERNEL); if (!datap) return -ENOMEM; - current->thread.vstate.datap = datap; - memset(¤t->thread.vstate, 0, offsetof(struct __riscv_v_ext_state, - datap)); + ctx->datap = datap; + memset(ctx, 0, offsetof(struct __riscv_v_ext_state, datap)); return 0; } +void riscv_v_thread_alloc(struct task_struct *tsk) +{ +#ifdef CONFIG_RISCV_ISA_V_PREEMPTIVE + riscv_v_thread_zalloc(riscv_v_kernel_cachep, &tsk->thread.kernel_vstate); +#endif +} + void riscv_v_thread_free(struct task_struct *tsk) { if (tsk->thread.vstate.datap) kmem_cache_free(riscv_v_user_cachep, tsk->thread.vstate.datap); +#ifdef CONFIG_RISCV_ISA_V_PREEMPTIVE + if (tsk->thread.kernel_vstate.datap) + kmem_cache_free(riscv_v_kernel_cachep, tsk->thread.kernel_vstate.datap); +#endif } #define VSTATE_CTRL_GET_CUR(x) ((x) & PR_RISCV_V_VSTATE_CTRL_CUR_MASK) @@ -180,7 +199,7 @@ bool riscv_v_first_use_handler(struct pt_regs *regs) * context where VS has been off. So, try to allocate the user's V * context and resume execution. */ - if (riscv_v_thread_zalloc()) { + if (riscv_v_thread_zalloc(riscv_v_user_cachep, ¤t->thread.vstate)) { force_sig(SIGBUS); return true; } |