d/numam-dpdk
1
0
Fork 0
Code Issues Pull Requests Projects Releases Wiki Activity

bpf: fix x86 JIT for immediate loads

Browse Source 
x86 jit can generate invalid code for (BPF_LD | BPF_IMM | EBPF_DW)
instructions, when immediate value is bigger then INT32_MAX.

Fixes: cc752e43e079 ("bpf: add JIT compilation for x86_64 ISA")
Cc: stable@dpdk.org

Signed-off-by: Konstantin Ananyev <konstantin.ananyev@intel.com>
This commit is contained in:
Konstantin Ananyev 2018-11-08 12:36:43 +00:00 committed by Thomas Monjalon
parent 31f19a9beb
commit 95df7307a7
1 changed files with 20 additions and 8 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

28
lib/librte_bpf/bpf_jit_x86.c
View File

@ -208,6 +208,19 @@ emit_sib(struct bpf_jit_state *st, uint32_t scale, uint32_t idx, uint32_t base)
emit_bytes(st, &v, sizeof(v));
}
/*
* emit OPCODE+REGIDX byte
*/
static void
emit_opcode(struct bpf_jit_state *st, uint8_t ops, uint32_t reg)
{
uint8_t v;
v = ops | (reg & 7);
emit_bytes(st, &v, sizeof(v));
}
/*
* emit xchg %<sreg>, %<dreg>
*/
@ -472,19 +485,18 @@ static void
emit_ld_imm64(struct bpf_jit_state *st, uint32_t dreg, uint32_t imm0,
uint32_t imm1)
{
uint32_t op;
const uint8_t ops = 0xB8;
if (imm1 == 0) {
emit_mov_imm(st, EBPF_ALU64 | EBPF_MOV | BPF_K, dreg, imm0);
return;
}
op = (imm1 == 0) ? BPF_ALU : EBPF_ALU64;
emit_rex(st, EBPF_ALU64, 0, dreg);
emit_bytes(st, &ops, sizeof(ops));
emit_modregrm(st, MOD_DIRECT, 0, dreg);
emit_rex(st, op, 0, dreg);
emit_opcode(st, ops, dreg);
emit_imm(st, imm0, sizeof(imm0));
emit_imm(st, imm1, sizeof(imm1));
if (imm1 != 0)
emit_imm(st, imm1, sizeof(imm1));
}
/*