aboutsummaryrefslogtreecommitdiff
path: root/arch/x86/net/bpf_jit_comp.c
diff options
context:
space:
mode:
Diffstat (limited to 'arch/x86/net/bpf_jit_comp.c')
-rw-r--r--arch/x86/net/bpf_jit_comp.c654
1 files changed, 654 insertions, 0 deletions
diff --git a/arch/x86/net/bpf_jit_comp.c b/arch/x86/net/bpf_jit_comp.c
new file mode 100644
index 00000000000..bfab3fa10ed
--- /dev/null
+++ b/arch/x86/net/bpf_jit_comp.c
@@ -0,0 +1,654 @@
+/* bpf_jit_comp.c : BPF JIT compiler
+ *
+ * Copyright (C) 2011 Eric Dumazet (eric.dumazet@gmail.com)
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; version 2
+ * of the License.
+ */
+#include <linux/moduleloader.h>
+#include <asm/cacheflush.h>
+#include <linux/netdevice.h>
+#include <linux/filter.h>
+
+/*
+ * Conventions :
+ * EAX : BPF A accumulator
+ * EBX : BPF X accumulator
+ * RDI : pointer to skb (first argument given to JIT function)
+ * RBP : frame pointer (even if CONFIG_FRAME_POINTER=n)
+ * ECX,EDX,ESI : scratch registers
+ * r9d : skb->len - skb->data_len (headlen)
+ * r8 : skb->data
+ * -8(RBP) : saved RBX value
+ * -16(RBP)..-80(RBP) : BPF_MEMWORDS values
+ */
+int bpf_jit_enable __read_mostly;
+
+/*
+ * assembly code in arch/x86/net/bpf_jit.S
+ */
+extern u8 sk_load_word[], sk_load_half[], sk_load_byte[], sk_load_byte_msh[];
+extern u8 sk_load_word_ind[], sk_load_half_ind[], sk_load_byte_ind[];
+
+static inline u8 *emit_code(u8 *ptr, u32 bytes, unsigned int len)
+{
+ if (len == 1)
+ *ptr = bytes;
+ else if (len == 2)
+ *(u16 *)ptr = bytes;
+ else {
+ *(u32 *)ptr = bytes;
+ barrier();
+ }
+ return ptr + len;
+}
+
+#define EMIT(bytes, len) do { prog = emit_code(prog, bytes, len); } while (0)
+
+#define EMIT1(b1) EMIT(b1, 1)
+#define EMIT2(b1, b2) EMIT((b1) + ((b2) << 8), 2)
+#define EMIT3(b1, b2, b3) EMIT((b1) + ((b2) << 8) + ((b3) << 16), 3)
+#define EMIT4(b1, b2, b3, b4) EMIT((b1) + ((b2) << 8) + ((b3) << 16) + ((b4) << 24), 4)
+#define EMIT1_off32(b1, off) do { EMIT1(b1); EMIT(off, 4);} while (0)
+
+#define CLEAR_A() EMIT2(0x31, 0xc0) /* xor %eax,%eax */
+#define CLEAR_X() EMIT2(0x31, 0xdb) /* xor %ebx,%ebx */
+
+static inline bool is_imm8(int value)
+{
+ return value <= 127 && value >= -128;
+}
+
+static inline bool is_near(int offset)
+{
+ return offset <= 127 && offset >= -128;
+}
+
+#define EMIT_JMP(offset) \
+do { \
+ if (offset) { \
+ if (is_near(offset)) \
+ EMIT2(0xeb, offset); /* jmp .+off8 */ \
+ else \
+ EMIT1_off32(0xe9, offset); /* jmp .+off32 */ \
+ } \
+} while (0)
+
+/* list of x86 cond jumps opcodes (. + s8)
+ * Add 0x10 (and an extra 0x0f) to generate far jumps (. + s32)
+ */
+#define X86_JB 0x72
+#define X86_JAE 0x73
+#define X86_JE 0x74
+#define X86_JNE 0x75
+#define X86_JBE 0x76
+#define X86_JA 0x77
+
+#define EMIT_COND_JMP(op, offset) \
+do { \
+ if (is_near(offset)) \
+ EMIT2(op, offset); /* jxx .+off8 */ \
+ else { \
+ EMIT2(0x0f, op + 0x10); \
+ EMIT(offset, 4); /* jxx .+off32 */ \
+ } \
+} while (0)
+
+#define COND_SEL(CODE, TOP, FOP) \
+ case CODE: \
+ t_op = TOP; \
+ f_op = FOP; \
+ goto cond_branch
+
+
+#define SEEN_DATAREF 1 /* might call external helpers */
+#define SEEN_XREG 2 /* ebx is used */
+#define SEEN_MEM 4 /* use mem[] for temporary storage */
+
+static inline void bpf_flush_icache(void *start, void *end)
+{
+ mm_segment_t old_fs = get_fs();
+
+ set_fs(KERNEL_DS);
+ smp_wmb();
+ flush_icache_range((unsigned long)start, (unsigned long)end);
+ set_fs(old_fs);
+}
+
+
+void bpf_jit_compile(struct sk_filter *fp)
+{
+ u8 temp[64];
+ u8 *prog;
+ unsigned int proglen, oldproglen = 0;
+ int ilen, i;
+ int t_offset, f_offset;
+ u8 t_op, f_op, seen = 0, pass;
+ u8 *image = NULL;
+ u8 *func;
+ int pc_ret0 = -1; /* bpf index of first RET #0 instruction (if any) */
+ unsigned int cleanup_addr; /* epilogue code offset */
+ unsigned int *addrs;
+ const struct sock_filter *filter = fp->insns;
+ int flen = fp->len;
+
+ if (!bpf_jit_enable)
+ return;
+
+ addrs = kmalloc(flen * sizeof(*addrs), GFP_KERNEL);
+ if (addrs == NULL)
+ return;
+
+ /* Before first pass, make a rough estimation of addrs[]
+ * each bpf instruction is translated to less than 64 bytes
+ */
+ for (proglen = 0, i = 0; i < flen; i++) {
+ proglen += 64;
+ addrs[i] = proglen;
+ }
+ cleanup_addr = proglen; /* epilogue address */
+
+ for (pass = 0; pass < 10; pass++) {
+ /* no prologue/epilogue for trivial filters (RET something) */
+ proglen = 0;
+ prog = temp;
+
+ if (seen) {
+ EMIT4(0x55, 0x48, 0x89, 0xe5); /* push %rbp; mov %rsp,%rbp */
+ EMIT4(0x48, 0x83, 0xec, 96); /* subq $96,%rsp */
+ /* note : must save %rbx in case bpf_error is hit */
+ if (seen & (SEEN_XREG | SEEN_DATAREF))
+ EMIT4(0x48, 0x89, 0x5d, 0xf8); /* mov %rbx, -8(%rbp) */
+ if (seen & SEEN_XREG)
+ CLEAR_X(); /* make sure we dont leek kernel memory */
+
+ /*
+ * If this filter needs to access skb data,
+ * loads r9 and r8 with :
+ * r9 = skb->len - skb->data_len
+ * r8 = skb->data
+ */
+ if (seen & SEEN_DATAREF) {
+ if (offsetof(struct sk_buff, len) <= 127)
+ /* mov off8(%rdi),%r9d */
+ EMIT4(0x44, 0x8b, 0x4f, offsetof(struct sk_buff, len));
+ else {
+ /* mov off32(%rdi),%r9d */
+ EMIT3(0x44, 0x8b, 0x8f);
+ EMIT(offsetof(struct sk_buff, len), 4);
+ }
+ if (is_imm8(offsetof(struct sk_buff, data_len)))
+ /* sub off8(%rdi),%r9d */
+ EMIT4(0x44, 0x2b, 0x4f, offsetof(struct sk_buff, data_len));
+ else {
+ EMIT3(0x44, 0x2b, 0x8f);
+ EMIT(offsetof(struct sk_buff, data_len), 4);
+ }
+
+ if (is_imm8(offsetof(struct sk_buff, data)))
+ /* mov off8(%rdi),%r8 */
+ EMIT4(0x4c, 0x8b, 0x47, offsetof(struct sk_buff, data));
+ else {
+ /* mov off32(%rdi),%r8 */
+ EMIT3(0x4c, 0x8b, 0x87);
+ EMIT(offsetof(struct sk_buff, data), 4);
+ }
+ }
+ }
+
+ switch (filter[0].code) {
+ case BPF_S_RET_K:
+ case BPF_S_LD_W_LEN:
+ case BPF_S_ANC_PROTOCOL:
+ case BPF_S_ANC_IFINDEX:
+ case BPF_S_ANC_MARK:
+ case BPF_S_ANC_RXHASH:
+ case BPF_S_ANC_CPU:
+ case BPF_S_ANC_QUEUE:
+ case BPF_S_LD_W_ABS:
+ case BPF_S_LD_H_ABS:
+ case BPF_S_LD_B_ABS:
+ /* first instruction sets A register (or is RET 'constant') */
+ break;
+ default:
+ /* make sure we dont leak kernel information to user */
+ CLEAR_A(); /* A = 0 */
+ }
+
+ for (i = 0; i < flen; i++) {
+ unsigned int K = filter[i].k;
+
+ switch (filter[i].code) {
+ case BPF_S_ALU_ADD_X: /* A += X; */
+ seen |= SEEN_XREG;
+ EMIT2(0x01, 0xd8); /* add %ebx,%eax */
+ break;
+ case BPF_S_ALU_ADD_K: /* A += K; */
+ if (!K)
+ break;
+ if (is_imm8(K))
+ EMIT3(0x83, 0xc0, K); /* add imm8,%eax */
+ else
+ EMIT1_off32(0x05, K); /* add imm32,%eax */
+ break;
+ case BPF_S_ALU_SUB_X: /* A -= X; */
+ seen |= SEEN_XREG;
+ EMIT2(0x29, 0xd8); /* sub %ebx,%eax */
+ break;
+ case BPF_S_ALU_SUB_K: /* A -= K */
+ if (!K)
+ break;
+ if (is_imm8(K))
+ EMIT3(0x83, 0xe8, K); /* sub imm8,%eax */
+ else
+ EMIT1_off32(0x2d, K); /* sub imm32,%eax */
+ break;
+ case BPF_S_ALU_MUL_X: /* A *= X; */
+ seen |= SEEN_XREG;
+ EMIT3(0x0f, 0xaf, 0xc3); /* imul %ebx,%eax */
+ break;
+ case BPF_S_ALU_MUL_K: /* A *= K */
+ if (is_imm8(K))
+ EMIT3(0x6b, 0xc0, K); /* imul imm8,%eax,%eax */
+ else {
+ EMIT2(0x69, 0xc0); /* imul imm32,%eax */
+ EMIT(K, 4);
+ }
+ break;
+ case BPF_S_ALU_DIV_X: /* A /= X; */
+ seen |= SEEN_XREG;
+ EMIT2(0x85, 0xdb); /* test %ebx,%ebx */
+ if (pc_ret0 != -1)
+ EMIT_COND_JMP(X86_JE, addrs[pc_ret0] - (addrs[i] - 4));
+ else {
+ EMIT_COND_JMP(X86_JNE, 2 + 5);
+ CLEAR_A();
+ EMIT1_off32(0xe9, cleanup_addr - (addrs[i] - 4)); /* jmp .+off32 */
+ }
+ EMIT4(0x31, 0xd2, 0xf7, 0xf3); /* xor %edx,%edx; div %ebx */
+ break;
+ case BPF_S_ALU_DIV_K: /* A = reciprocal_divide(A, K); */
+ EMIT3(0x48, 0x69, 0xc0); /* imul imm32,%rax,%rax */
+ EMIT(K, 4);
+ EMIT4(0x48, 0xc1, 0xe8, 0x20); /* shr $0x20,%rax */
+ break;
+ case BPF_S_ALU_AND_X:
+ seen |= SEEN_XREG;
+ EMIT2(0x21, 0xd8); /* and %ebx,%eax */
+ break;
+ case BPF_S_ALU_AND_K:
+ if (K >= 0xFFFFFF00) {
+ EMIT2(0x24, K & 0xFF); /* and imm8,%al */
+ } else if (K >= 0xFFFF0000) {
+ EMIT2(0x66, 0x25); /* and imm16,%ax */
+ EMIT2(K, 2);
+ } else {
+ EMIT1_off32(0x25, K); /* and imm32,%eax */
+ }
+ break;
+ case BPF_S_ALU_OR_X:
+ seen |= SEEN_XREG;
+ EMIT2(0x09, 0xd8); /* or %ebx,%eax */
+ break;
+ case BPF_S_ALU_OR_K:
+ if (is_imm8(K))
+ EMIT3(0x83, 0xc8, K); /* or imm8,%eax */
+ else
+ EMIT1_off32(0x0d, K); /* or 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 */
+ break;
+ case BPF_S_ALU_LSH_K:
+ if (K == 0)
+ break;
+ else if (K == 1)
+ EMIT2(0xd1, 0xe0); /* shl %eax */
+ else
+ EMIT3(0xc1, 0xe0, K);
+ break;
+ case BPF_S_ALU_RSH_X: /* A >>= X; */
+ seen |= SEEN_XREG;
+ EMIT4(0x89, 0xd9, 0xd3, 0xe8); /* mov %ebx,%ecx; shr %cl,%eax */
+ break;
+ case BPF_S_ALU_RSH_K: /* A >>= K; */
+ if (K == 0)
+ break;
+ else if (K == 1)
+ EMIT2(0xd1, 0xe8); /* shr %eax */
+ else
+ EMIT3(0xc1, 0xe8, K);
+ break;
+ case BPF_S_ALU_NEG:
+ EMIT2(0xf7, 0xd8); /* neg %eax */
+ break;
+ case BPF_S_RET_K:
+ if (!K) {
+ if (pc_ret0 == -1)
+ pc_ret0 = i;
+ CLEAR_A();
+ } else {
+ EMIT1_off32(0xb8, K); /* mov $imm32,%eax */
+ }
+ /* fallinto */
+ case BPF_S_RET_A:
+ if (seen) {
+ if (i != flen - 1) {
+ EMIT_JMP(cleanup_addr - addrs[i]);
+ break;
+ }
+ if (seen & SEEN_XREG)
+ EMIT4(0x48, 0x8b, 0x5d, 0xf8); /* mov -8(%rbp),%rbx */
+ EMIT1(0xc9); /* leaveq */
+ }
+ EMIT1(0xc3); /* ret */
+ break;
+ case BPF_S_MISC_TAX: /* X = A */
+ seen |= SEEN_XREG;
+ EMIT2(0x89, 0xc3); /* mov %eax,%ebx */
+ break;
+ case BPF_S_MISC_TXA: /* A = X */
+ seen |= SEEN_XREG;
+ EMIT2(0x89, 0xd8); /* mov %ebx,%eax */
+ break;
+ case BPF_S_LD_IMM: /* A = K */
+ if (!K)
+ CLEAR_A();
+ else
+ EMIT1_off32(0xb8, K); /* mov $imm32,%eax */
+ break;
+ case BPF_S_LDX_IMM: /* X = K */
+ seen |= SEEN_XREG;
+ if (!K)
+ CLEAR_X();
+ else
+ EMIT1_off32(0xbb, K); /* mov $imm32,%ebx */
+ break;
+ case BPF_S_LD_MEM: /* A = mem[K] : mov off8(%rbp),%eax */
+ seen |= SEEN_MEM;
+ EMIT3(0x8b, 0x45, 0xf0 - K*4);
+ break;
+ case BPF_S_LDX_MEM: /* X = mem[K] : mov off8(%rbp),%ebx */
+ seen |= SEEN_XREG | SEEN_MEM;
+ EMIT3(0x8b, 0x5d, 0xf0 - K*4);
+ break;
+ case BPF_S_ST: /* mem[K] = A : mov %eax,off8(%rbp) */
+ seen |= SEEN_MEM;
+ EMIT3(0x89, 0x45, 0xf0 - K*4);
+ break;
+ case BPF_S_STX: /* mem[K] = X : mov %ebx,off8(%rbp) */
+ seen |= SEEN_XREG | SEEN_MEM;
+ EMIT3(0x89, 0x5d, 0xf0 - K*4);
+ break;
+ case BPF_S_LD_W_LEN: /* A = skb->len; */
+ BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, len) != 4);
+ if (is_imm8(offsetof(struct sk_buff, len)))
+ /* mov off8(%rdi),%eax */
+ EMIT3(0x8b, 0x47, offsetof(struct sk_buff, len));
+ else {
+ EMIT2(0x8b, 0x87);
+ EMIT(offsetof(struct sk_buff, len), 4);
+ }
+ break;
+ case BPF_S_LDX_W_LEN: /* X = skb->len; */
+ seen |= SEEN_XREG;
+ if (is_imm8(offsetof(struct sk_buff, len)))
+ /* mov off8(%rdi),%ebx */
+ EMIT3(0x8b, 0x5f, offsetof(struct sk_buff, len));
+ else {
+ EMIT2(0x8b, 0x9f);
+ EMIT(offsetof(struct sk_buff, len), 4);
+ }
+ break;
+ case BPF_S_ANC_PROTOCOL: /* A = ntohs(skb->protocol); */
+ BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, protocol) != 2);
+ if (is_imm8(offsetof(struct sk_buff, protocol))) {
+ /* movzwl off8(%rdi),%eax */
+ EMIT4(0x0f, 0xb7, 0x47, offsetof(struct sk_buff, protocol));
+ } else {
+ EMIT3(0x0f, 0xb7, 0x87); /* movzwl off32(%rdi),%eax */
+ EMIT(offsetof(struct sk_buff, protocol), 4);
+ }
+ EMIT2(0x86, 0xc4); /* ntohs() : xchg %al,%ah */
+ break;
+ case BPF_S_ANC_IFINDEX:
+ if (is_imm8(offsetof(struct sk_buff, dev))) {
+ /* movq off8(%rdi),%rax */
+ EMIT4(0x48, 0x8b, 0x47, offsetof(struct sk_buff, dev));
+ } else {
+ EMIT3(0x48, 0x8b, 0x87); /* movq off32(%rdi),%rax */
+ EMIT(offsetof(struct sk_buff, dev), 4);
+ }
+ EMIT3(0x48, 0x85, 0xc0); /* test %rax,%rax */
+ EMIT_COND_JMP(X86_JE, cleanup_addr - (addrs[i] - 6));
+ BUILD_BUG_ON(FIELD_SIZEOF(struct net_device, ifindex) != 4);
+ EMIT2(0x8b, 0x80); /* mov off32(%rax),%eax */
+ EMIT(offsetof(struct net_device, ifindex), 4);
+ break;
+ case BPF_S_ANC_MARK:
+ BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, mark) != 4);
+ if (is_imm8(offsetof(struct sk_buff, mark))) {
+ /* mov off8(%rdi),%eax */
+ EMIT3(0x8b, 0x47, offsetof(struct sk_buff, mark));
+ } else {
+ EMIT2(0x8b, 0x87);
+ EMIT(offsetof(struct sk_buff, mark), 4);
+ }
+ break;
+ case BPF_S_ANC_RXHASH:
+ BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, rxhash) != 4);
+ if (is_imm8(offsetof(struct sk_buff, rxhash))) {
+ /* mov off8(%rdi),%eax */
+ EMIT3(0x8b, 0x47, offsetof(struct sk_buff, rxhash));
+ } else {
+ EMIT2(0x8b, 0x87);
+ EMIT(offsetof(struct sk_buff, rxhash), 4);
+ }
+ break;
+ case BPF_S_ANC_QUEUE:
+ BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, queue_mapping) != 2);
+ if (is_imm8(offsetof(struct sk_buff, queue_mapping))) {
+ /* movzwl off8(%rdi),%eax */
+ EMIT4(0x0f, 0xb7, 0x47, offsetof(struct sk_buff, queue_mapping));
+ } else {
+ EMIT3(0x0f, 0xb7, 0x87); /* movzwl off32(%rdi),%eax */
+ EMIT(offsetof(struct sk_buff, queue_mapping), 4);
+ }
+ break;
+ case BPF_S_ANC_CPU:
+#ifdef CONFIG_SMP
+ EMIT4(0x65, 0x8b, 0x04, 0x25); /* mov %gs:off32,%eax */
+ EMIT((u32)(unsigned long)&cpu_number, 4); /* A = smp_processor_id(); */
+#else
+ CLEAR_A();
+#endif
+ break;
+ case BPF_S_LD_W_ABS:
+ func = sk_load_word;
+common_load: seen |= SEEN_DATAREF;
+ if ((int)K < 0)
+ goto out;
+ t_offset = func - (image + addrs[i]);
+ EMIT1_off32(0xbe, K); /* mov imm32,%esi */
+ EMIT1_off32(0xe8, t_offset); /* call */
+ break;
+ case BPF_S_LD_H_ABS:
+ func = sk_load_half;
+ goto common_load;
+ case BPF_S_LD_B_ABS:
+ func = sk_load_byte;
+ goto common_load;
+ case BPF_S_LDX_B_MSH:
+ if ((int)K < 0) {
+ if (pc_ret0 != -1) {
+ EMIT_JMP(addrs[pc_ret0] - addrs[i]);
+ break;
+ }
+ CLEAR_A();
+ EMIT_JMP(cleanup_addr - addrs[i]);
+ break;
+ }
+ seen |= SEEN_DATAREF | SEEN_XREG;
+ t_offset = sk_load_byte_msh - (image + addrs[i]);
+ EMIT1_off32(0xbe, K); /* mov imm32,%esi */
+ EMIT1_off32(0xe8, t_offset); /* call sk_load_byte_msh */
+ break;
+ case BPF_S_LD_W_IND:
+ func = sk_load_word_ind;
+common_load_ind: seen |= SEEN_DATAREF | SEEN_XREG;
+ t_offset = func - (image + addrs[i]);
+ EMIT1_off32(0xbe, K); /* mov imm32,%esi */
+ EMIT1_off32(0xe8, t_offset); /* call sk_load_xxx_ind */
+ break;
+ case BPF_S_LD_H_IND:
+ func = sk_load_half_ind;
+ goto common_load_ind;
+ case BPF_S_LD_B_IND:
+ func = sk_load_byte_ind;
+ goto common_load_ind;
+ case BPF_S_JMP_JA:
+ t_offset = addrs[i + K] - addrs[i];
+ EMIT_JMP(t_offset);
+ break;
+ COND_SEL(BPF_S_JMP_JGT_K, X86_JA, X86_JBE);
+ COND_SEL(BPF_S_JMP_JGE_K, X86_JAE, X86_JB);
+ COND_SEL(BPF_S_JMP_JEQ_K, X86_JE, X86_JNE);
+ COND_SEL(BPF_S_JMP_JSET_K,X86_JNE, X86_JE);
+ COND_SEL(BPF_S_JMP_JGT_X, X86_JA, X86_JBE);
+ COND_SEL(BPF_S_JMP_JGE_X, X86_JAE, X86_JB);
+ COND_SEL(BPF_S_JMP_JEQ_X, X86_JE, X86_JNE);
+ COND_SEL(BPF_S_JMP_JSET_X,X86_JNE, X86_JE);
+
+cond_branch: f_offset = addrs[i + filter[i].jf] - addrs[i];
+ t_offset = addrs[i + filter[i].jt] - addrs[i];
+
+ /* same targets, can avoid doing the test :) */
+ if (filter[i].jt == filter[i].jf) {
+ EMIT_JMP(t_offset);
+ break;
+ }
+
+ switch (filter[i].code) {
+ case BPF_S_JMP_JGT_X:
+ case BPF_S_JMP_JGE_X:
+ case BPF_S_JMP_JEQ_X:
+ seen |= SEEN_XREG;
+ EMIT2(0x39, 0xd8); /* cmp %ebx,%eax */
+ break;
+ case BPF_S_JMP_JSET_X:
+ seen |= SEEN_XREG;
+ EMIT2(0x85, 0xd8); /* test %ebx,%eax */
+ break;
+ case BPF_S_JMP_JEQ_K:
+ if (K == 0) {
+ EMIT2(0x85, 0xc0); /* test %eax,%eax */
+ break;
+ }
+ case BPF_S_JMP_JGT_K:
+ case BPF_S_JMP_JGE_K:
+ if (K <= 127)
+ EMIT3(0x83, 0xf8, K); /* cmp imm8,%eax */
+ else
+ EMIT1_off32(0x3d, K); /* cmp imm32,%eax */
+ break;
+ case BPF_S_JMP_JSET_K:
+ if (K <= 0xFF)
+ EMIT2(0xa8, K); /* test imm8,%al */
+ else if (!(K & 0xFFFF00FF))
+ EMIT3(0xf6, 0xc4, K >> 8); /* test imm8,%ah */
+ else if (K <= 0xFFFF) {
+ EMIT2(0x66, 0xa9); /* test imm16,%ax */
+ EMIT(K, 2);
+ } else {
+ EMIT1_off32(0xa9, K); /* test imm32,%eax */
+ }
+ break;
+ }
+ if (filter[i].jt != 0) {
+ if (filter[i].jf)
+ t_offset += is_near(f_offset) ? 2 : 6;
+ EMIT_COND_JMP(t_op, t_offset);
+ if (filter[i].jf)
+ EMIT_JMP(f_offset);
+ break;
+ }
+ EMIT_COND_JMP(f_op, f_offset);
+ break;
+ default:
+ /* hmm, too complex filter, give up with jit compiler */
+ goto out;
+ }
+ ilen = prog - temp;
+ if (image) {
+ if (unlikely(proglen + ilen > oldproglen)) {
+ pr_err("bpb_jit_compile fatal error\n");
+ kfree(addrs);
+ module_free(NULL, image);
+ return;
+ }
+ memcpy(image + proglen, temp, ilen);
+ }
+ proglen += ilen;
+ addrs[i] = proglen;
+ prog = temp;
+ }
+ /* last bpf instruction is always a RET :
+ * use it to give the cleanup instruction(s) addr
+ */
+ cleanup_addr = proglen - 1; /* ret */
+ if (seen)
+ cleanup_addr -= 1; /* leaveq */
+ if (seen & SEEN_XREG)
+ cleanup_addr -= 4; /* mov -8(%rbp),%rbx */
+
+ if (image) {
+ WARN_ON(proglen != oldproglen);
+ break;
+ }
+ if (proglen == oldproglen) {
+ image = module_alloc(max_t(unsigned int,
+ proglen,
+ sizeof(struct work_struct)));
+ if (!image)
+ goto out;
+ }
+ oldproglen = proglen;
+ }
+ if (bpf_jit_enable > 1)
+ pr_err("flen=%d proglen=%u pass=%d image=%p\n",
+ flen, proglen, pass, image);
+
+ if (image) {
+ if (bpf_jit_enable > 1)
+ print_hex_dump(KERN_ERR, "JIT code: ", DUMP_PREFIX_ADDRESS,
+ 16, 1, image, proglen, false);
+
+ bpf_flush_icache(image, image + proglen);
+
+ fp->bpf_func = (void *)image;
+ }
+out:
+ kfree(addrs);
+ return;
+}
+
+static void jit_free_defer(struct work_struct *arg)
+{
+ module_free(NULL, arg);
+}
+
+/* run from softirq, we must use a work_struct to call
+ * module_free() from process context
+ */
+void bpf_jit_free(struct sk_filter *fp)
+{
+ if (fp->bpf_func != sk_run_filter) {
+ struct work_struct *work = (struct work_struct *)fp->bpf_func;
+
+ INIT_WORK(work, jit_free_defer);
+ schedule_work(work);
+ }
+}
generated by cgit v1.2.3-18-g5258 (git 2.32.0) at 2024-11-24 11:13:27 +0000