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| author | Russell King <rmk+kernel@armlinux.org.uk> | 2018-07-11 11:32:28 +0200 |
|---|---|---|
| committer | Daniel Borkmann <daniel@iogearbox.net> | 2018-07-12 20:45:23 +0200 |
| commit | b50452299864fbc00a576241e1490541c8754d50 (patch) | |
| tree | 2adf24333f066f1e17a0f2247cce8f0be89b0602 | |
| parent | ARM: net: bpf: avoid reloading 'index' (diff) | |
| download | linux-b50452299864fbc00a576241e1490541c8754d50.tar.xz linux-b50452299864fbc00a576241e1490541c8754d50.zip | |
ARM: net: bpf: avoid reloading 'array'
Rearranging the order of the initial tail call code a little allows is
to avoid reloading the 'array' pointer.
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
| -rw-r--r-- | arch/arm/net/bpf_jit_32.c | 9 |
1 files changed, 4 insertions, 5 deletions
diff --git a/arch/arm/net/bpf_jit_32.c b/arch/arm/net/bpf_jit_32.c index 0a8b3d0903c4..f0cad9692952 100644 --- a/arch/arm/net/bpf_jit_32.c +++ b/arch/arm/net/bpf_jit_32.c @@ -1064,16 +1064,16 @@ static int emit_bpf_tail_call(struct jit_ctx *ctx) BUILD_BUG_ON(offsetof(struct bpf_array, map.max_entries) > ARM_INST_LDST__IMM12); off = offsetof(struct bpf_array, map.max_entries); - /* array->map.max_entries */ - r_array = arm_bpf_get_reg32(r2[1], tmp2[1], ctx); - emit(ARM_LDR_I(tmp[1], r_array, off), ctx); + r_array = arm_bpf_get_reg32(r2[1], tmp2[0], ctx); /* index is 32-bit for arrays */ r_index = arm_bpf_get_reg32(r3[1], tmp2[1], ctx); + /* array->map.max_entries */ + emit(ARM_LDR_I(tmp[1], r_array, off), ctx); /* index >= array->map.max_entries */ emit(ARM_CMP_R(r_index, tmp[1]), ctx); _emit(ARM_COND_CS, ARM_B(jmp_offset), ctx); - /* tmp2[1] = index */ + /* tmp2[0] = array, tmp2[1] = index */ /* if (tail_call_cnt > MAX_TAIL_CALL_CNT) * goto out; @@ -1095,7 +1095,6 @@ static int emit_bpf_tail_call(struct jit_ctx *ctx) */ BUILD_BUG_ON(imm8m(offsetof(struct bpf_array, ptrs)) < 0); off = imm8m(offsetof(struct bpf_array, ptrs)); - r_array = arm_bpf_get_reg32(r2[1], tmp2[0], ctx); emit(ARM_ADD_I(tmp[1], r_array, off), ctx); emit(ARM_LDR_R_SI(tmp[1], tmp[1], r_index, SRTYPE_ASL, 2), ctx); emit(ARM_CMP_I(tmp[1], 0), ctx); |