From bd446f5df5afab212917f6732ba6442a5e8de85e Mon Sep 17 00:00:00 2001 From: Andy Chiu Date: Mon, 15 Jan 2024 05:59:28 +0000 Subject: riscv: vector: use kmem_cache to manage vector context MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit The allocation size of thread.vstate.datap is always riscv_v_vsize. So it is possbile to use kmem_cache_* to manage the allocation. This gives users more information regarding allocation of vector context via /proc/slabinfo. And it potentially reduces the latency of the first-use trap because of the allocation caches. Signed-off-by: Andy Chiu Tested-by: Björn Töpel Tested-by: Lad Prabhakar Link: https://lore.kernel.org/r/20240115055929.4736-10-andy.chiu@sifive.com Signed-off-by: Palmer Dabbelt --- arch/riscv/include/asm/vector.h | 4 ++++ arch/riscv/kernel/process.c | 7 ++++++- arch/riscv/kernel/vector.c | 19 ++++++++++++++++++- 3 files changed, 28 insertions(+), 2 deletions(-) (limited to 'arch') diff --git a/arch/riscv/include/asm/vector.h b/arch/riscv/include/asm/vector.h index d75079520629..7b316050f24f 100644 --- a/arch/riscv/include/asm/vector.h +++ b/arch/riscv/include/asm/vector.h @@ -26,6 +26,8 @@ void kernel_vector_begin(void); void kernel_vector_end(void); void get_cpu_vector_context(void); void put_cpu_vector_context(void); +void riscv_v_thread_free(struct task_struct *tsk); +void __init riscv_v_setup_ctx_cache(void); static inline u32 riscv_v_flags(void) { @@ -227,6 +229,8 @@ static inline bool riscv_v_vstate_ctrl_user_allowed(void) { return false; } #define __switch_to_vector(__prev, __next) do {} while (0) #define riscv_v_vstate_off(regs) do {} while (0) #define riscv_v_vstate_on(regs) do {} while (0) +#define riscv_v_thread_free(tsk) do {} while (0) +#define riscv_v_setup_ctx_cache() do {} while (0) #endif /* CONFIG_RISCV_ISA_V */ diff --git a/arch/riscv/kernel/process.c b/arch/riscv/kernel/process.c index 36993f408de4..862d59c3872e 100644 --- a/arch/riscv/kernel/process.c +++ b/arch/riscv/kernel/process.c @@ -179,7 +179,7 @@ void arch_release_task_struct(struct task_struct *tsk) { /* Free the vector context of datap. */ if (has_vector()) - kfree(tsk->thread.vstate.datap); + riscv_v_thread_free(tsk); } int arch_dup_task_struct(struct task_struct *dst, struct task_struct *src) @@ -228,3 +228,8 @@ int copy_thread(struct task_struct *p, const struct kernel_clone_args *args) p->thread.sp = (unsigned long)childregs; /* kernel sp */ return 0; } + +void __init arch_task_cache_init(void) +{ + riscv_v_setup_ctx_cache(); +} diff --git a/arch/riscv/kernel/vector.c b/arch/riscv/kernel/vector.c index c1f28bc89ec6..f7b4aeb9e457 100644 --- a/arch/riscv/kernel/vector.c +++ b/arch/riscv/kernel/vector.c @@ -21,6 +21,7 @@ #include static bool riscv_v_implicit_uacc = IS_ENABLED(CONFIG_RISCV_ISA_V_DEFAULT_ENABLE); +static struct kmem_cache *riscv_v_user_cachep; unsigned long riscv_v_vsize __read_mostly; EXPORT_SYMBOL_GPL(riscv_v_vsize); @@ -47,6 +48,16 @@ int riscv_v_setup_vsize(void) return 0; } +void __init riscv_v_setup_ctx_cache(void) +{ + if (!has_vector()) + return; + + riscv_v_user_cachep = kmem_cache_create_usercopy("riscv_vector_ctx", + riscv_v_vsize, 16, SLAB_PANIC, + 0, riscv_v_vsize, NULL); +} + static bool insn_is_vector(u32 insn_buf) { u32 opcode = insn_buf & __INSN_OPCODE_MASK; @@ -84,7 +95,7 @@ static int riscv_v_thread_zalloc(void) { void *datap; - datap = kzalloc(riscv_v_vsize, GFP_KERNEL); + datap = kmem_cache_zalloc(riscv_v_user_cachep, GFP_KERNEL); if (!datap) return -ENOMEM; @@ -94,6 +105,12 @@ static int riscv_v_thread_zalloc(void) return 0; } +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); +} + #define VSTATE_CTRL_GET_CUR(x) ((x) & PR_RISCV_V_VSTATE_CTRL_CUR_MASK) #define VSTATE_CTRL_GET_NEXT(x) (((x) & PR_RISCV_V_VSTATE_CTRL_NEXT_MASK) >> 2) #define VSTATE_CTRL_MAKE_NEXT(x) (((x) << 2) & PR_RISCV_V_VSTATE_CTRL_NEXT_MASK) -- cgit v1.2.3