On Thu Jun 4, 2026 at 1:22 PM PDT, Alexis Lothoré (eBPF Foundation) wrote: > 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);
maybe it's an opportunity to cover this into separate helper function? When indent reaches 4 tabs it's about time.
