From f9ff5018c13b4918c98178ee81d41372b455201e Mon Sep 17 00:00:00 2001 From: Russell King Date: Thu, 12 Jul 2018 21:50:41 +0100 Subject: [PATCH] ARM: net: bpf: improve 64-bit load immediate implementation Rather than writing each 32-bit half of the 64-bit immediate value separately when the register is on the stack: movw r6, #45056 ; 0xb000 movt r6, #60979 ; 0xee33 str r6, [fp, #-44] ; 0xffffffd4 mov r6, #0 str r6, [fp, #-40] ; 0xffffffd8 arrange to use the double-word store when available instead: movw r6, #45056 ; 0xb000 movt r6, #60979 ; 0xee33 mov r7, #0 strd r6, [fp, #-44] ; 0xffffffd4 Signed-off-by: Russell King Signed-off-by: Daniel Borkmann --- arch/arm/net/bpf_jit_32.c | 32 ++++++++++++++++++++------------ 1 file changed, 20 insertions(+), 12 deletions(-) diff --git a/arch/arm/net/bpf_jit_32.c b/arch/arm/net/bpf_jit_32.c index a9f68a924800..6558bd73bbb9 100644 --- a/arch/arm/net/bpf_jit_32.c +++ b/arch/arm/net/bpf_jit_32.c @@ -599,9 +599,20 @@ static inline void emit_a32_mov_i(const s8 dst, const u32 val, } } +static void emit_a32_mov_i64(const s8 dst[], u64 val, struct jit_ctx *ctx) +{ + const s8 *tmp = bpf2a32[TMP_REG_1]; + const s8 *rd = is_stacked(dst_lo) ? tmp : dst; + + emit_mov_i(rd[1], (u32)val, ctx); + emit_mov_i(rd[0], val >> 32, ctx); + + arm_bpf_put_reg64(dst, rd, ctx); +} + /* Sign extended move */ -static inline void emit_a32_mov_i64(const bool is64, const s8 dst[], - const u32 val, struct jit_ctx *ctx) { +static inline void emit_a32_mov_se_i64(const bool is64, const s8 dst[], + const u32 val, struct jit_ctx *ctx) { u32 hi = 0; if (is64 && (val & (1<<31))) @@ -1309,7 +1320,7 @@ static int build_insn(const struct bpf_insn *insn, struct jit_ctx *ctx) break; case BPF_K: /* Sign-extend immediate value to destination reg */ - emit_a32_mov_i64(is64, dst, imm, ctx); + emit_a32_mov_se_i64(is64, dst, imm, ctx); break; } break; @@ -1358,7 +1369,7 @@ static int build_insn(const struct bpf_insn *insn, struct jit_ctx *ctx) * value into temporary reg and then it would be * safe to do the operation on it. */ - emit_a32_mov_i64(is64, tmp2, imm, ctx); + emit_a32_mov_se_i64(is64, tmp2, imm, ctx); emit_a32_alu_r64(is64, dst, tmp2, ctx, BPF_OP(code)); break; } @@ -1454,7 +1465,7 @@ static int build_insn(const struct bpf_insn *insn, struct jit_ctx *ctx) * reg then it would be safe to do the operation * on it. */ - emit_a32_mov_i64(is64, tmp2, imm, ctx); + emit_a32_mov_se_i64(is64, tmp2, imm, ctx); emit_a32_mul_r64(dst, tmp2, ctx); break; } @@ -1506,12 +1517,9 @@ static int build_insn(const struct bpf_insn *insn, struct jit_ctx *ctx) /* dst = imm64 */ case BPF_LD | BPF_IMM | BPF_DW: { - const struct bpf_insn insn1 = insn[1]; - u32 hi, lo = imm; + u64 val = (u32)imm | (u64)insn[1].imm << 32; - hi = insn1.imm; - emit_a32_mov_i(dst_lo, lo, ctx); - emit_a32_mov_i(dst_hi, hi, ctx); + emit_a32_mov_i64(dst, val, ctx); return 1; } @@ -1531,7 +1539,7 @@ static int build_insn(const struct bpf_insn *insn, struct jit_ctx *ctx) switch (BPF_SIZE(code)) { case BPF_DW: /* Sign-extend immediate value into temp reg */ - emit_a32_mov_i64(true, tmp2, imm, ctx); + emit_a32_mov_se_i64(true, tmp2, imm, ctx); emit_str_r(dst_lo, tmp2[1], off, ctx, BPF_W); emit_str_r(dst_lo, tmp2[0], off+4, ctx, BPF_W); break; @@ -1620,7 +1628,7 @@ static int build_insn(const struct bpf_insn *insn, struct jit_ctx *ctx) rm = tmp2[0]; rn = tmp2[1]; /* Sign-extend immediate value */ - emit_a32_mov_i64(true, tmp2, imm, ctx); + emit_a32_mov_se_i64(true, tmp2, imm, ctx); go_jmp: /* Setup destination register */ rd = arm_bpf_get_reg64(dst, tmp, ctx); -- GitLab