In order to prepare for KASAN checks insertion before every memory-related load or store, group all BPF_ST instructions that indeed access memory in a single block of fall-through cases to allow instrumenting those in one call, rather than having to instrument all cases individually.
Signed-off-by: Alexis Lothoré (eBPF Foundation) <[email protected]> --- arch/x86/net/bpf_jit_comp.c | 53 ++++++++++++++++++++++++++------------------- 1 file changed, 31 insertions(+), 22 deletions(-) diff --git a/arch/x86/net/bpf_jit_comp.c b/arch/x86/net/bpf_jit_comp.c index 0981791014eb..943a0f315cf2 100644 --- a/arch/x86/net/bpf_jit_comp.c +++ b/arch/x86/net/bpf_jit_comp.c @@ -2300,41 +2300,50 @@ static int do_jit(struct bpf_verifier_env *env, struct bpf_prog *bpf_prog, int * EMIT_LFENCE(); break; - /* ST: *(u8*)(dst_reg + off) = imm */ case BPF_ST | BPF_MEM | BPF_B: - if (is_ereg(dst_reg)) - EMIT2(0x41, 0xC6); - else - EMIT1(0xC6); - goto st; case BPF_ST | BPF_MEM | BPF_H: - if (is_ereg(dst_reg)) - EMIT3(0x66, 0x41, 0xC7); - else - EMIT2(0x66, 0xC7); - goto st; case BPF_ST | BPF_MEM | BPF_W: - if (is_ereg(dst_reg)) - EMIT2(0x41, 0xC7); - else - EMIT1(0xC7); - goto st; case BPF_ST | BPF_MEM | BPF_DW: - if (dst_reg == BPF_REG_PARAMS && insn->off == -8) { - /* Arg 6: store immediate in r9 register */ - emit_mov_imm64(&prog, X86_REG_R9, imm32 >> 31, (u32)imm32); + switch (BPF_SIZE(insn->code)) { + case BPF_B: + if (is_ereg(dst_reg)) + EMIT2(0x41, 0xC6); + else + EMIT1(0xC6); + break; + case BPF_H: + if (is_ereg(dst_reg)) + EMIT3(0x66, 0x41, 0xC7); + else + EMIT2(0x66, 0xC7); + break; + case BPF_W: + if (is_ereg(dst_reg)) + EMIT2(0x41, 0xC7); + else + EMIT1(0xC7); + break; + case BPF_DW: + if (dst_reg == BPF_REG_PARAMS && + insn->off == -8) { + /* Arg 6: store immediate in r9 register */ + emit_mov_imm64(&prog, X86_REG_R9, + imm32 >> 31, (u32)imm32); + break; + } + EMIT2(add_1mod(0x48, dst_reg), 0xC7); break; } - EMIT2(add_1mod(0x48, dst_reg), 0xC7); -st: insn_off = insn->off; + insn_off = insn->off; if (dst_reg == BPF_REG_PARAMS) { /* * Args 7+: reverse BPF negative offsets to * x86 positive rsp offsets. * BPF off=-16 → [rsp+0], off=-24 → [rsp+8], ... */ - insn_off = outgoing_arg_base - outgoing_rsp - insn_off - 16; + insn_off = outgoing_arg_base - outgoing_rsp - + insn_off - 16; dst_reg = BPF_REG_FP; } if (is_imm8(insn_off)) -- 2.54.0
