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x86 bpf_jit: support MOD operation

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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>
This commit is contained in:
Eric Dumazet 2012-09-10 22:48:33 +02:00 • committed by David S. Miller
commit 280050cc81
1 changed files with 25 additions and 0 deletions
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25
arch/x86/net/bpf_jit_comp.c
View file

@ -280,6 +280,31 @@ void bpf_jit_compile(struct sk_filter *fp)
}
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);