From 96a27ee76f0e95b56f94b6902da7a5ebef372612 Mon Sep 17 00:00:00 2001 From: Xiao Wang Date: Fri, 24 May 2024 15:55:43 +0800 Subject: [PATCH] riscv, bpf: Introduce shift add helper with Zba optimization MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Zba extension is very useful for generating addresses that index into array of basic data types. This patch introduces sh2add and sh3add helpers for RV32 and RV64 respectively, to accelerate addressing for array of unsigned long data. Signed-off-by: Xiao Wang Signed-off-by: Daniel Borkmann Acked-by: Björn Töpel Link: https://lore.kernel.org/bpf/20240524075543.4050464-3-xiao.w.wang@intel.com --- arch/riscv/net/bpf_jit.h | 33 +++++++++++++++++++++++++++++++++ arch/riscv/net/bpf_jit_comp32.c | 3 +-- arch/riscv/net/bpf_jit_comp64.c | 9 +++------ 3 files changed, 37 insertions(+), 8 deletions(-) diff --git a/arch/riscv/net/bpf_jit.h b/arch/riscv/net/bpf_jit.h index 97041b58237a..1d1c78d4cff1 100644 --- a/arch/riscv/net/bpf_jit.h +++ b/arch/riscv/net/bpf_jit.h @@ -742,6 +742,17 @@ static inline u16 rvc_swsp(u32 imm8, u8 rs2) return rv_css_insn(0x6, imm, rs2, 0x2); } +/* RVZBA instructions. */ +static inline u32 rvzba_sh2add(u8 rd, u8 rs1, u8 rs2) +{ + return rv_r_insn(0x10, rs2, rs1, 0x4, rd, 0x33); +} + +static inline u32 rvzba_sh3add(u8 rd, u8 rs1, u8 rs2) +{ + return rv_r_insn(0x10, rs2, rs1, 0x6, rd, 0x33); +} + /* RVZBB instructions. */ static inline u32 rvzbb_sextb(u8 rd, u8 rs1) { @@ -1095,6 +1106,28 @@ static inline void emit_sw(u8 rs1, s32 off, u8 rs2, struct rv_jit_context *ctx) emit(rv_sw(rs1, off, rs2), ctx); } +static inline void emit_sh2add(u8 rd, u8 rs1, u8 rs2, struct rv_jit_context *ctx) +{ + if (rvzba_enabled()) { + emit(rvzba_sh2add(rd, rs1, rs2), ctx); + return; + } + + emit_slli(rd, rs1, 2, ctx); + emit_add(rd, rd, rs2, ctx); +} + +static inline void emit_sh3add(u8 rd, u8 rs1, u8 rs2, struct rv_jit_context *ctx) +{ + if (rvzba_enabled()) { + emit(rvzba_sh3add(rd, rs1, rs2), ctx); + return; + } + + emit_slli(rd, rs1, 3, ctx); + emit_add(rd, rd, rs2, ctx); +} + /* RV64-only helper functions. */ #if __riscv_xlen == 64 diff --git a/arch/riscv/net/bpf_jit_comp32.c b/arch/riscv/net/bpf_jit_comp32.c index f5ba73bb153d..592dd86fbf81 100644 --- a/arch/riscv/net/bpf_jit_comp32.c +++ b/arch/riscv/net/bpf_jit_comp32.c @@ -811,8 +811,7 @@ static int emit_bpf_tail_call(int insn, struct rv_jit_context *ctx) * if (!prog) * goto out; */ - emit(rv_slli(RV_REG_T0, lo(idx_reg), 2), ctx); - emit(rv_add(RV_REG_T0, RV_REG_T0, lo(arr_reg)), ctx); + emit_sh2add(RV_REG_T0, lo(idx_reg), lo(arr_reg), ctx); off = offsetof(struct bpf_array, ptrs); if (is_12b_check(off, insn)) return -1; diff --git a/arch/riscv/net/bpf_jit_comp64.c b/arch/riscv/net/bpf_jit_comp64.c index 2bc4c14ea59a..d5cebb0b0afe 100644 --- a/arch/riscv/net/bpf_jit_comp64.c +++ b/arch/riscv/net/bpf_jit_comp64.c @@ -380,8 +380,7 @@ static int emit_bpf_tail_call(int insn, struct rv_jit_context *ctx) * if (!prog) * goto out; */ - emit_slli(RV_REG_T2, RV_REG_A2, 3, ctx); - emit_add(RV_REG_T2, RV_REG_T2, RV_REG_A1, ctx); + emit_sh3add(RV_REG_T2, RV_REG_A2, RV_REG_A1, ctx); off = offsetof(struct bpf_array, ptrs); if (is_12b_check(off, insn)) return -1; @@ -1099,12 +1098,10 @@ int bpf_jit_emit_insn(const struct bpf_insn *insn, struct rv_jit_context *ctx, /* Load current CPU number in T1 */ emit_ld(RV_REG_T1, offsetof(struct thread_info, cpu), RV_REG_TP, ctx); - /* << 3 because offsets are 8 bytes */ - emit_slli(RV_REG_T1, RV_REG_T1, 3, ctx); /* Load address of __per_cpu_offset array in T2 */ emit_addr(RV_REG_T2, (u64)&__per_cpu_offset, extra_pass, ctx); - /* Add offset of current CPU to __per_cpu_offset */ - emit_add(RV_REG_T1, RV_REG_T2, RV_REG_T1, ctx); + /* Get address of __per_cpu_offset[cpu] in T1 */ + emit_sh3add(RV_REG_T1, RV_REG_T1, RV_REG_T2, ctx); /* Load __per_cpu_offset[cpu] in T1 */ emit_ld(RV_REG_T1, 0, RV_REG_T1, ctx); /* Add the offset to Rd */