x86: bpf_jit_comp: add XOR instruction for BPF JIT

[~andy/linux] / arch / x86 / net / bpf_jit_comp.c

diff --git a/arch/x86/net/bpf_jit_comp.c b/arch/x86/net/bpf_jit_comp.c
index 33643a8bcbbb0f1887dc2f815fe469aaf0e0507a..520d2bd0b9c583de16ce246ffbf938c5c9f48b33 100644 (file)
--- a/arch/x86/net/bpf_jit_comp.c
+++ b/arch/x86/net/bpf_jit_comp.c
@@ -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);
@@ -310,9 +335,18 @@ void bpf_jit_compile(struct sk_filter *fp)
                                        EMIT1_off32(0x0d, K);   /* or imm32,%eax */
                                break;
                        case BPF_S_ANC_ALU_XOR_X: /* A ^= X; */
+                       case BPF_S_ALU_XOR_X:
                                seen |= SEEN_XREG;
                                EMIT2(0x31, 0xd8);              /* xor %ebx,%eax */
                                break;
+                       case BPF_S_ALU_XOR_K: /* A ^= K; */
+                               if (K == 0)
+                                       break;
+                               if (is_imm8(K))
+                                       EMIT3(0x83, 0xf0, K);   /* xor imm8,%eax */
+                               else
+                                       EMIT1_off32(0x35, K);   /* xor imm32,%eax */
+                               break;
                        case BPF_S_ALU_LSH_X: /* A <<= X; */
                                seen |= SEEN_XREG;
                                EMIT4(0x89, 0xd9, 0xd3, 0xe0);  /* mov %ebx,%ecx; shl %cl,%eax */