x86 bpf_jit: support MOD operation
commit b6069a9570 (filter: add MOD operation) added generic
support for modulus operation in BPF.
This patch brings JIT support for x86_64
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: George Bakos <gbakos@alpinista.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/arch/x86/net/bpf_jit_comp.c b/arch/x86/net/bpf_jit_comp.c
index 33643a8..106c578 100644
--- a/arch/x86/net/bpf_jit_comp.c
+++ b/arch/x86/net/bpf_jit_comp.c
@@ -280,6 +280,31 @@
}
EMIT4(0x31, 0xd2, 0xf7, 0xf3); /* xor %edx,%edx; div %ebx */
break;
+ case BPF_S_ALU_MOD_X: /* A %= X; */
+ seen |= SEEN_XREG;
+ EMIT2(0x85, 0xdb); /* test %ebx,%ebx */
+ if (pc_ret0 > 0) {
+ /* addrs[pc_ret0 - 1] is start address of target
+ * (addrs[i] - 6) is the address following this jmp
+ * ("xor %edx,%edx; div %ebx;mov %edx,%eax" being 6 bytes long)
+ */
+ EMIT_COND_JMP(X86_JE, addrs[pc_ret0 - 1] -
+ (addrs[i] - 6));
+ } else {
+ EMIT_COND_JMP(X86_JNE, 2 + 5);
+ CLEAR_A();
+ EMIT1_off32(0xe9, cleanup_addr - (addrs[i] - 6)); /* jmp .+off32 */
+ }
+ EMIT2(0x31, 0xd2); /* xor %edx,%edx */
+ EMIT2(0xf7, 0xf3); /* div %ebx */
+ EMIT2(0x89, 0xd0); /* mov %edx,%eax */
+ break;
+ case BPF_S_ALU_MOD_K: /* A %= K; */
+ EMIT2(0x31, 0xd2); /* xor %edx,%edx */
+ EMIT1(0xb9);EMIT(K, 4); /* mov imm32,%ecx */
+ EMIT2(0xf7, 0xf1); /* div %ecx */
+ EMIT2(0x89, 0xd0); /* mov %edx,%eax */
+ break;
case BPF_S_ALU_DIV_K: /* A = reciprocal_divide(A, K); */
EMIT3(0x48, 0x69, 0xc0); /* imul imm32,%rax,%rax */
EMIT(K, 4);