summaryrefslogtreecommitdiffstats
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.c1190
1 files changed, 1190 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 000000000..81c3d4b4c
--- /dev/null
+++ b/arch/x86/net/bpf_jit_comp.c
@@ -0,0 +1,1190 @@
+/*
+ * bpf_jit_comp.c: BPF JIT compiler
+ *
+ * Copyright (C) 2011-2013 Eric Dumazet (eric.dumazet@gmail.com)
+ * Internal BPF Copyright (c) 2011-2014 PLUMgrid, http://plumgrid.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/netdevice.h>
+#include <linux/filter.h>
+#include <linux/if_vlan.h>
+#include <linux/bpf.h>
+
+#include <asm/set_memory.h>
+#include <asm/nospec-branch.h>
+
+static 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); cnt += 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 EMIT2_off32(b1, b2, off) \
+ do { EMIT2(b1, b2); EMIT(off, 4); } while (0)
+#define EMIT3_off32(b1, b2, b3, off) \
+ do { EMIT3(b1, b2, b3); EMIT(off, 4); } while (0)
+#define EMIT4_off32(b1, b2, b3, b4, off) \
+ do { EMIT4(b1, b2, b3, b4); EMIT(off, 4); } while (0)
+
+static bool is_imm8(int value)
+{
+ return value <= 127 && value >= -128;
+}
+
+static bool is_simm32(s64 value)
+{
+ return value == (s64)(s32)value;
+}
+
+static bool is_uimm32(u64 value)
+{
+ return value == (u64)(u32)value;
+}
+
+/* mov dst, src */
+#define EMIT_mov(DST, SRC) \
+ do { \
+ if (DST != SRC) \
+ EMIT3(add_2mod(0x48, DST, SRC), 0x89, add_2reg(0xC0, DST, SRC)); \
+ } while (0)
+
+static int bpf_size_to_x86_bytes(int bpf_size)
+{
+ if (bpf_size == BPF_W)
+ return 4;
+ else if (bpf_size == BPF_H)
+ return 2;
+ else if (bpf_size == BPF_B)
+ return 1;
+ else if (bpf_size == BPF_DW)
+ return 4; /* imm32 */
+ else
+ return 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 X86_JL 0x7C
+#define X86_JGE 0x7D
+#define X86_JLE 0x7E
+#define X86_JG 0x7F
+
+/* Pick a register outside of BPF range for JIT internal work */
+#define AUX_REG (MAX_BPF_JIT_REG + 1)
+
+/*
+ * The following table maps BPF registers to x86-64 registers.
+ *
+ * x86-64 register R12 is unused, since if used as base address
+ * register in load/store instructions, it always needs an
+ * extra byte of encoding and is callee saved.
+ *
+ * Also x86-64 register R9 is unused. x86-64 register R10 is
+ * used for blinding (if enabled).
+ */
+static const int reg2hex[] = {
+ [BPF_REG_0] = 0, /* RAX */
+ [BPF_REG_1] = 7, /* RDI */
+ [BPF_REG_2] = 6, /* RSI */
+ [BPF_REG_3] = 2, /* RDX */
+ [BPF_REG_4] = 1, /* RCX */
+ [BPF_REG_5] = 0, /* R8 */
+ [BPF_REG_6] = 3, /* RBX callee saved */
+ [BPF_REG_7] = 5, /* R13 callee saved */
+ [BPF_REG_8] = 6, /* R14 callee saved */
+ [BPF_REG_9] = 7, /* R15 callee saved */
+ [BPF_REG_FP] = 5, /* RBP readonly */
+ [BPF_REG_AX] = 2, /* R10 temp register */
+ [AUX_REG] = 3, /* R11 temp register */
+};
+
+/*
+ * is_ereg() == true if BPF register 'reg' maps to x86-64 r8..r15
+ * which need extra byte of encoding.
+ * rax,rcx,...,rbp have simpler encoding
+ */
+static bool is_ereg(u32 reg)
+{
+ return (1 << reg) & (BIT(BPF_REG_5) |
+ BIT(AUX_REG) |
+ BIT(BPF_REG_7) |
+ BIT(BPF_REG_8) |
+ BIT(BPF_REG_9) |
+ BIT(BPF_REG_AX));
+}
+
+/*
+ * is_ereg_8l() == true if BPF register 'reg' is mapped to access x86-64
+ * lower 8-bit registers dil,sil,bpl,spl,r8b..r15b, which need extra byte
+ * of encoding. al,cl,dl,bl have simpler encoding.
+ */
+static bool is_ereg_8l(u32 reg)
+{
+ return is_ereg(reg) ||
+ (1 << reg) & (BIT(BPF_REG_1) |
+ BIT(BPF_REG_2) |
+ BIT(BPF_REG_FP));
+}
+
+static bool is_axreg(u32 reg)
+{
+ return reg == BPF_REG_0;
+}
+
+/* Add modifiers if 'reg' maps to x86-64 registers R8..R15 */
+static u8 add_1mod(u8 byte, u32 reg)
+{
+ if (is_ereg(reg))
+ byte |= 1;
+ return byte;
+}
+
+static u8 add_2mod(u8 byte, u32 r1, u32 r2)
+{
+ if (is_ereg(r1))
+ byte |= 1;
+ if (is_ereg(r2))
+ byte |= 4;
+ return byte;
+}
+
+/* Encode 'dst_reg' register into x86-64 opcode 'byte' */
+static u8 add_1reg(u8 byte, u32 dst_reg)
+{
+ return byte + reg2hex[dst_reg];
+}
+
+/* Encode 'dst_reg' and 'src_reg' registers into x86-64 opcode 'byte' */
+static u8 add_2reg(u8 byte, u32 dst_reg, u32 src_reg)
+{
+ return byte + reg2hex[dst_reg] + (reg2hex[src_reg] << 3);
+}
+
+static void jit_fill_hole(void *area, unsigned int size)
+{
+ /* Fill whole space with INT3 instructions */
+ memset(area, 0xcc, size);
+}
+
+struct jit_context {
+ int cleanup_addr; /* Epilogue code offset */
+};
+
+/* Maximum number of bytes emitted while JITing one eBPF insn */
+#define BPF_MAX_INSN_SIZE 128
+#define BPF_INSN_SAFETY 64
+
+#define PROLOGUE_SIZE 20
+
+/*
+ * Emit x86-64 prologue code for BPF program and check its size.
+ * bpf_tail_call helper will skip it while jumping into another program
+ */
+static void emit_prologue(u8 **pprog, u32 stack_depth, bool ebpf_from_cbpf)
+{
+ u8 *prog = *pprog;
+ int cnt = 0;
+
+ EMIT1(0x55); /* push rbp */
+ EMIT3(0x48, 0x89, 0xE5); /* mov rbp, rsp */
+ /* sub rsp, rounded_stack_depth */
+ EMIT3_off32(0x48, 0x81, 0xEC, round_up(stack_depth, 8));
+ EMIT1(0x53); /* push rbx */
+ EMIT2(0x41, 0x55); /* push r13 */
+ EMIT2(0x41, 0x56); /* push r14 */
+ EMIT2(0x41, 0x57); /* push r15 */
+ if (!ebpf_from_cbpf) {
+ /* zero init tail_call_cnt */
+ EMIT2(0x6a, 0x00);
+ BUILD_BUG_ON(cnt != PROLOGUE_SIZE);
+ }
+ *pprog = prog;
+}
+
+/*
+ * Generate the following code:
+ *
+ * ... bpf_tail_call(void *ctx, struct bpf_array *array, u64 index) ...
+ * if (index >= array->map.max_entries)
+ * goto out;
+ * if (++tail_call_cnt > MAX_TAIL_CALL_CNT)
+ * goto out;
+ * prog = array->ptrs[index];
+ * if (prog == NULL)
+ * goto out;
+ * goto *(prog->bpf_func + prologue_size);
+ * out:
+ */
+static void emit_bpf_tail_call(u8 **pprog)
+{
+ u8 *prog = *pprog;
+ int label1, label2, label3;
+ int cnt = 0;
+
+ /*
+ * rdi - pointer to ctx
+ * rsi - pointer to bpf_array
+ * rdx - index in bpf_array
+ */
+
+ /*
+ * if (index >= array->map.max_entries)
+ * goto out;
+ */
+ EMIT2(0x89, 0xD2); /* mov edx, edx */
+ EMIT3(0x39, 0x56, /* cmp dword ptr [rsi + 16], edx */
+ offsetof(struct bpf_array, map.max_entries));
+#define OFFSET1 (41 + RETPOLINE_RAX_BPF_JIT_SIZE) /* Number of bytes to jump */
+ EMIT2(X86_JBE, OFFSET1); /* jbe out */
+ label1 = cnt;
+
+ /*
+ * if (tail_call_cnt > MAX_TAIL_CALL_CNT)
+ * goto out;
+ */
+ EMIT2_off32(0x8B, 0x85, -36 - MAX_BPF_STACK); /* mov eax, dword ptr [rbp - 548] */
+ EMIT3(0x83, 0xF8, MAX_TAIL_CALL_CNT); /* cmp eax, MAX_TAIL_CALL_CNT */
+#define OFFSET2 (30 + RETPOLINE_RAX_BPF_JIT_SIZE)
+ EMIT2(X86_JA, OFFSET2); /* ja out */
+ label2 = cnt;
+ EMIT3(0x83, 0xC0, 0x01); /* add eax, 1 */
+ EMIT2_off32(0x89, 0x85, -36 - MAX_BPF_STACK); /* mov dword ptr [rbp -548], eax */
+
+ /* prog = array->ptrs[index]; */
+ EMIT4_off32(0x48, 0x8B, 0x84, 0xD6, /* mov rax, [rsi + rdx * 8 + offsetof(...)] */
+ offsetof(struct bpf_array, ptrs));
+
+ /*
+ * if (prog == NULL)
+ * goto out;
+ */
+ EMIT3(0x48, 0x85, 0xC0); /* test rax,rax */
+#define OFFSET3 (8 + RETPOLINE_RAX_BPF_JIT_SIZE)
+ EMIT2(X86_JE, OFFSET3); /* je out */
+ label3 = cnt;
+
+ /* goto *(prog->bpf_func + prologue_size); */
+ EMIT4(0x48, 0x8B, 0x40, /* mov rax, qword ptr [rax + 32] */
+ offsetof(struct bpf_prog, bpf_func));
+ EMIT4(0x48, 0x83, 0xC0, PROLOGUE_SIZE); /* add rax, prologue_size */
+
+ /*
+ * Wow we're ready to jump into next BPF program
+ * rdi == ctx (1st arg)
+ * rax == prog->bpf_func + prologue_size
+ */
+ RETPOLINE_RAX_BPF_JIT();
+
+ /* out: */
+ BUILD_BUG_ON(cnt - label1 != OFFSET1);
+ BUILD_BUG_ON(cnt - label2 != OFFSET2);
+ BUILD_BUG_ON(cnt - label3 != OFFSET3);
+ *pprog = prog;
+}
+
+static void emit_mov_imm32(u8 **pprog, bool sign_propagate,
+ u32 dst_reg, const u32 imm32)
+{
+ u8 *prog = *pprog;
+ u8 b1, b2, b3;
+ int cnt = 0;
+
+ /*
+ * Optimization: if imm32 is positive, use 'mov %eax, imm32'
+ * (which zero-extends imm32) to save 2 bytes.
+ */
+ if (sign_propagate && (s32)imm32 < 0) {
+ /* 'mov %rax, imm32' sign extends imm32 */
+ b1 = add_1mod(0x48, dst_reg);
+ b2 = 0xC7;
+ b3 = 0xC0;
+ EMIT3_off32(b1, b2, add_1reg(b3, dst_reg), imm32);
+ goto done;
+ }
+
+ /*
+ * Optimization: if imm32 is zero, use 'xor %eax, %eax'
+ * to save 3 bytes.
+ */
+ if (imm32 == 0) {
+ if (is_ereg(dst_reg))
+ EMIT1(add_2mod(0x40, dst_reg, dst_reg));
+ b2 = 0x31; /* xor */
+ b3 = 0xC0;
+ EMIT2(b2, add_2reg(b3, dst_reg, dst_reg));
+ goto done;
+ }
+
+ /* mov %eax, imm32 */
+ if (is_ereg(dst_reg))
+ EMIT1(add_1mod(0x40, dst_reg));
+ EMIT1_off32(add_1reg(0xB8, dst_reg), imm32);
+done:
+ *pprog = prog;
+}
+
+static void emit_mov_imm64(u8 **pprog, u32 dst_reg,
+ const u32 imm32_hi, const u32 imm32_lo)
+{
+ u8 *prog = *pprog;
+ int cnt = 0;
+
+ if (is_uimm32(((u64)imm32_hi << 32) | (u32)imm32_lo)) {
+ /*
+ * For emitting plain u32, where sign bit must not be
+ * propagated LLVM tends to load imm64 over mov32
+ * directly, so save couple of bytes by just doing
+ * 'mov %eax, imm32' instead.
+ */
+ emit_mov_imm32(&prog, false, dst_reg, imm32_lo);
+ } else {
+ /* movabsq %rax, imm64 */
+ EMIT2(add_1mod(0x48, dst_reg), add_1reg(0xB8, dst_reg));
+ EMIT(imm32_lo, 4);
+ EMIT(imm32_hi, 4);
+ }
+
+ *pprog = prog;
+}
+
+static void emit_mov_reg(u8 **pprog, bool is64, u32 dst_reg, u32 src_reg)
+{
+ u8 *prog = *pprog;
+ int cnt = 0;
+
+ if (is64) {
+ /* mov dst, src */
+ EMIT_mov(dst_reg, src_reg);
+ } else {
+ /* mov32 dst, src */
+ if (is_ereg(dst_reg) || is_ereg(src_reg))
+ EMIT1(add_2mod(0x40, dst_reg, src_reg));
+ EMIT2(0x89, add_2reg(0xC0, dst_reg, src_reg));
+ }
+
+ *pprog = prog;
+}
+
+static int do_jit(struct bpf_prog *bpf_prog, int *addrs, u8 *image,
+ int oldproglen, struct jit_context *ctx)
+{
+ struct bpf_insn *insn = bpf_prog->insnsi;
+ int insn_cnt = bpf_prog->len;
+ bool seen_exit = false;
+ u8 temp[BPF_MAX_INSN_SIZE + BPF_INSN_SAFETY];
+ int i, cnt = 0;
+ int proglen = 0;
+ u8 *prog = temp;
+
+ emit_prologue(&prog, bpf_prog->aux->stack_depth,
+ bpf_prog_was_classic(bpf_prog));
+
+ for (i = 0; i < insn_cnt; i++, insn++) {
+ const s32 imm32 = insn->imm;
+ u32 dst_reg = insn->dst_reg;
+ u32 src_reg = insn->src_reg;
+ u8 b2 = 0, b3 = 0;
+ s64 jmp_offset;
+ u8 jmp_cond;
+ int ilen;
+ u8 *func;
+
+ switch (insn->code) {
+ /* ALU */
+ case BPF_ALU | BPF_ADD | BPF_X:
+ case BPF_ALU | BPF_SUB | BPF_X:
+ case BPF_ALU | BPF_AND | BPF_X:
+ case BPF_ALU | BPF_OR | BPF_X:
+ case BPF_ALU | BPF_XOR | BPF_X:
+ case BPF_ALU64 | BPF_ADD | BPF_X:
+ case BPF_ALU64 | BPF_SUB | BPF_X:
+ case BPF_ALU64 | BPF_AND | BPF_X:
+ case BPF_ALU64 | BPF_OR | BPF_X:
+ case BPF_ALU64 | BPF_XOR | BPF_X:
+ switch (BPF_OP(insn->code)) {
+ case BPF_ADD: b2 = 0x01; break;
+ case BPF_SUB: b2 = 0x29; break;
+ case BPF_AND: b2 = 0x21; break;
+ case BPF_OR: b2 = 0x09; break;
+ case BPF_XOR: b2 = 0x31; break;
+ }
+ if (BPF_CLASS(insn->code) == BPF_ALU64)
+ EMIT1(add_2mod(0x48, dst_reg, src_reg));
+ else if (is_ereg(dst_reg) || is_ereg(src_reg))
+ EMIT1(add_2mod(0x40, dst_reg, src_reg));
+ EMIT2(b2, add_2reg(0xC0, dst_reg, src_reg));
+ break;
+
+ case BPF_ALU64 | BPF_MOV | BPF_X:
+ case BPF_ALU | BPF_MOV | BPF_X:
+ emit_mov_reg(&prog,
+ BPF_CLASS(insn->code) == BPF_ALU64,
+ dst_reg, src_reg);
+ break;
+
+ /* neg dst */
+ case BPF_ALU | BPF_NEG:
+ case BPF_ALU64 | BPF_NEG:
+ if (BPF_CLASS(insn->code) == BPF_ALU64)
+ EMIT1(add_1mod(0x48, dst_reg));
+ else if (is_ereg(dst_reg))
+ EMIT1(add_1mod(0x40, dst_reg));
+ EMIT2(0xF7, add_1reg(0xD8, dst_reg));
+ break;
+
+ case BPF_ALU | BPF_ADD | BPF_K:
+ case BPF_ALU | BPF_SUB | BPF_K:
+ case BPF_ALU | BPF_AND | BPF_K:
+ case BPF_ALU | BPF_OR | BPF_K:
+ case BPF_ALU | BPF_XOR | BPF_K:
+ case BPF_ALU64 | BPF_ADD | BPF_K:
+ case BPF_ALU64 | BPF_SUB | BPF_K:
+ case BPF_ALU64 | BPF_AND | BPF_K:
+ case BPF_ALU64 | BPF_OR | BPF_K:
+ case BPF_ALU64 | BPF_XOR | BPF_K:
+ if (BPF_CLASS(insn->code) == BPF_ALU64)
+ EMIT1(add_1mod(0x48, dst_reg));
+ else if (is_ereg(dst_reg))
+ EMIT1(add_1mod(0x40, dst_reg));
+
+ /*
+ * b3 holds 'normal' opcode, b2 short form only valid
+ * in case dst is eax/rax.
+ */
+ switch (BPF_OP(insn->code)) {
+ case BPF_ADD:
+ b3 = 0xC0;
+ b2 = 0x05;
+ break;
+ case BPF_SUB:
+ b3 = 0xE8;
+ b2 = 0x2D;
+ break;
+ case BPF_AND:
+ b3 = 0xE0;
+ b2 = 0x25;
+ break;
+ case BPF_OR:
+ b3 = 0xC8;
+ b2 = 0x0D;
+ break;
+ case BPF_XOR:
+ b3 = 0xF0;
+ b2 = 0x35;
+ break;
+ }
+
+ if (is_imm8(imm32))
+ EMIT3(0x83, add_1reg(b3, dst_reg), imm32);
+ else if (is_axreg(dst_reg))
+ EMIT1_off32(b2, imm32);
+ else
+ EMIT2_off32(0x81, add_1reg(b3, dst_reg), imm32);
+ break;
+
+ case BPF_ALU64 | BPF_MOV | BPF_K:
+ case BPF_ALU | BPF_MOV | BPF_K:
+ emit_mov_imm32(&prog, BPF_CLASS(insn->code) == BPF_ALU64,
+ dst_reg, imm32);
+ break;
+
+ case BPF_LD | BPF_IMM | BPF_DW:
+ emit_mov_imm64(&prog, dst_reg, insn[1].imm, insn[0].imm);
+ insn++;
+ i++;
+ break;
+
+ /* dst %= src, dst /= src, dst %= imm32, dst /= imm32 */
+ case BPF_ALU | BPF_MOD | BPF_X:
+ case BPF_ALU | BPF_DIV | BPF_X:
+ case BPF_ALU | BPF_MOD | BPF_K:
+ case BPF_ALU | BPF_DIV | BPF_K:
+ case BPF_ALU64 | BPF_MOD | BPF_X:
+ case BPF_ALU64 | BPF_DIV | BPF_X:
+ case BPF_ALU64 | BPF_MOD | BPF_K:
+ case BPF_ALU64 | BPF_DIV | BPF_K:
+ EMIT1(0x50); /* push rax */
+ EMIT1(0x52); /* push rdx */
+
+ if (BPF_SRC(insn->code) == BPF_X)
+ /* mov r11, src_reg */
+ EMIT_mov(AUX_REG, src_reg);
+ else
+ /* mov r11, imm32 */
+ EMIT3_off32(0x49, 0xC7, 0xC3, imm32);
+
+ /* mov rax, dst_reg */
+ EMIT_mov(BPF_REG_0, dst_reg);
+
+ /*
+ * xor edx, edx
+ * equivalent to 'xor rdx, rdx', but one byte less
+ */
+ EMIT2(0x31, 0xd2);
+
+ if (BPF_CLASS(insn->code) == BPF_ALU64)
+ /* div r11 */
+ EMIT3(0x49, 0xF7, 0xF3);
+ else
+ /* div r11d */
+ EMIT3(0x41, 0xF7, 0xF3);
+
+ if (BPF_OP(insn->code) == BPF_MOD)
+ /* mov r11, rdx */
+ EMIT3(0x49, 0x89, 0xD3);
+ else
+ /* mov r11, rax */
+ EMIT3(0x49, 0x89, 0xC3);
+
+ EMIT1(0x5A); /* pop rdx */
+ EMIT1(0x58); /* pop rax */
+
+ /* mov dst_reg, r11 */
+ EMIT_mov(dst_reg, AUX_REG);
+ break;
+
+ case BPF_ALU | BPF_MUL | BPF_K:
+ case BPF_ALU | BPF_MUL | BPF_X:
+ case BPF_ALU64 | BPF_MUL | BPF_K:
+ case BPF_ALU64 | BPF_MUL | BPF_X:
+ {
+ bool is64 = BPF_CLASS(insn->code) == BPF_ALU64;
+
+ if (dst_reg != BPF_REG_0)
+ EMIT1(0x50); /* push rax */
+ if (dst_reg != BPF_REG_3)
+ EMIT1(0x52); /* push rdx */
+
+ /* mov r11, dst_reg */
+ EMIT_mov(AUX_REG, dst_reg);
+
+ if (BPF_SRC(insn->code) == BPF_X)
+ emit_mov_reg(&prog, is64, BPF_REG_0, src_reg);
+ else
+ emit_mov_imm32(&prog, is64, BPF_REG_0, imm32);
+
+ if (is64)
+ EMIT1(add_1mod(0x48, AUX_REG));
+ else if (is_ereg(AUX_REG))
+ EMIT1(add_1mod(0x40, AUX_REG));
+ /* mul(q) r11 */
+ EMIT2(0xF7, add_1reg(0xE0, AUX_REG));
+
+ if (dst_reg != BPF_REG_3)
+ EMIT1(0x5A); /* pop rdx */
+ if (dst_reg != BPF_REG_0) {
+ /* mov dst_reg, rax */
+ EMIT_mov(dst_reg, BPF_REG_0);
+ EMIT1(0x58); /* pop rax */
+ }
+ break;
+ }
+ /* Shifts */
+ case BPF_ALU | BPF_LSH | BPF_K:
+ case BPF_ALU | BPF_RSH | BPF_K:
+ case BPF_ALU | BPF_ARSH | BPF_K:
+ case BPF_ALU64 | BPF_LSH | BPF_K:
+ case BPF_ALU64 | BPF_RSH | BPF_K:
+ case BPF_ALU64 | BPF_ARSH | BPF_K:
+ if (BPF_CLASS(insn->code) == BPF_ALU64)
+ EMIT1(add_1mod(0x48, dst_reg));
+ else if (is_ereg(dst_reg))
+ EMIT1(add_1mod(0x40, dst_reg));
+
+ switch (BPF_OP(insn->code)) {
+ case BPF_LSH: b3 = 0xE0; break;
+ case BPF_RSH: b3 = 0xE8; break;
+ case BPF_ARSH: b3 = 0xF8; break;
+ }
+
+ if (imm32 == 1)
+ EMIT2(0xD1, add_1reg(b3, dst_reg));
+ else
+ EMIT3(0xC1, add_1reg(b3, dst_reg), imm32);
+ break;
+
+ case BPF_ALU | BPF_LSH | BPF_X:
+ case BPF_ALU | BPF_RSH | BPF_X:
+ case BPF_ALU | BPF_ARSH | BPF_X:
+ case BPF_ALU64 | BPF_LSH | BPF_X:
+ case BPF_ALU64 | BPF_RSH | BPF_X:
+ case BPF_ALU64 | BPF_ARSH | BPF_X:
+
+ /* Check for bad case when dst_reg == rcx */
+ if (dst_reg == BPF_REG_4) {
+ /* mov r11, dst_reg */
+ EMIT_mov(AUX_REG, dst_reg);
+ dst_reg = AUX_REG;
+ }
+
+ if (src_reg != BPF_REG_4) { /* common case */
+ EMIT1(0x51); /* push rcx */
+
+ /* mov rcx, src_reg */
+ EMIT_mov(BPF_REG_4, src_reg);
+ }
+
+ /* shl %rax, %cl | shr %rax, %cl | sar %rax, %cl */
+ if (BPF_CLASS(insn->code) == BPF_ALU64)
+ EMIT1(add_1mod(0x48, dst_reg));
+ else if (is_ereg(dst_reg))
+ EMIT1(add_1mod(0x40, dst_reg));
+
+ switch (BPF_OP(insn->code)) {
+ case BPF_LSH: b3 = 0xE0; break;
+ case BPF_RSH: b3 = 0xE8; break;
+ case BPF_ARSH: b3 = 0xF8; break;
+ }
+ EMIT2(0xD3, add_1reg(b3, dst_reg));
+
+ if (src_reg != BPF_REG_4)
+ EMIT1(0x59); /* pop rcx */
+
+ if (insn->dst_reg == BPF_REG_4)
+ /* mov dst_reg, r11 */
+ EMIT_mov(insn->dst_reg, AUX_REG);
+ break;
+
+ case BPF_ALU | BPF_END | BPF_FROM_BE:
+ switch (imm32) {
+ case 16:
+ /* Emit 'ror %ax, 8' to swap lower 2 bytes */
+ EMIT1(0x66);
+ if (is_ereg(dst_reg))
+ EMIT1(0x41);
+ EMIT3(0xC1, add_1reg(0xC8, dst_reg), 8);
+
+ /* Emit 'movzwl eax, ax' */
+ if (is_ereg(dst_reg))
+ EMIT3(0x45, 0x0F, 0xB7);
+ else
+ EMIT2(0x0F, 0xB7);
+ EMIT1(add_2reg(0xC0, dst_reg, dst_reg));
+ break;
+ case 32:
+ /* Emit 'bswap eax' to swap lower 4 bytes */
+ if (is_ereg(dst_reg))
+ EMIT2(0x41, 0x0F);
+ else
+ EMIT1(0x0F);
+ EMIT1(add_1reg(0xC8, dst_reg));
+ break;
+ case 64:
+ /* Emit 'bswap rax' to swap 8 bytes */
+ EMIT3(add_1mod(0x48, dst_reg), 0x0F,
+ add_1reg(0xC8, dst_reg));
+ break;
+ }
+ break;
+
+ case BPF_ALU | BPF_END | BPF_FROM_LE:
+ switch (imm32) {
+ case 16:
+ /*
+ * Emit 'movzwl eax, ax' to zero extend 16-bit
+ * into 64 bit
+ */
+ if (is_ereg(dst_reg))
+ EMIT3(0x45, 0x0F, 0xB7);
+ else
+ EMIT2(0x0F, 0xB7);
+ EMIT1(add_2reg(0xC0, dst_reg, dst_reg));
+ break;
+ case 32:
+ /* Emit 'mov eax, eax' to clear upper 32-bits */
+ if (is_ereg(dst_reg))
+ EMIT1(0x45);
+ EMIT2(0x89, add_2reg(0xC0, dst_reg, dst_reg));
+ break;
+ case 64:
+ /* nop */
+ break;
+ }
+ break;
+
+ /* speculation barrier */
+ case BPF_ST | BPF_NOSPEC:
+ if (boot_cpu_has(X86_FEATURE_XMM2))
+ /* Emit 'lfence' */
+ EMIT3(0x0F, 0xAE, 0xE8);
+ break;
+
+ /* ST: *(u8*)(dst_reg + off) = imm */
+ case BPF_ST | BPF_MEM | BPF_B:
+ if (is_ereg(dst_reg))
+ EMIT2(0x41, 0xC6);
+ else
+ EMIT1(0xC6);
+ goto st;
+ case BPF_ST | BPF_MEM | BPF_H:
+ if (is_ereg(dst_reg))
+ EMIT3(0x66, 0x41, 0xC7);
+ else
+ EMIT2(0x66, 0xC7);
+ goto st;
+ case BPF_ST | BPF_MEM | BPF_W:
+ if (is_ereg(dst_reg))
+ EMIT2(0x41, 0xC7);
+ else
+ EMIT1(0xC7);
+ goto st;
+ case BPF_ST | BPF_MEM | BPF_DW:
+ EMIT2(add_1mod(0x48, dst_reg), 0xC7);
+
+st: if (is_imm8(insn->off))
+ EMIT2(add_1reg(0x40, dst_reg), insn->off);
+ else
+ EMIT1_off32(add_1reg(0x80, dst_reg), insn->off);
+
+ EMIT(imm32, bpf_size_to_x86_bytes(BPF_SIZE(insn->code)));
+ break;
+
+ /* STX: *(u8*)(dst_reg + off) = src_reg */
+ case BPF_STX | BPF_MEM | BPF_B:
+ /* Emit 'mov byte ptr [rax + off], al' */
+ if (is_ereg(dst_reg) || is_ereg_8l(src_reg))
+ /* Add extra byte for eregs or SIL,DIL,BPL in src_reg */
+ EMIT2(add_2mod(0x40, dst_reg, src_reg), 0x88);
+ else
+ EMIT1(0x88);
+ goto stx;
+ case BPF_STX | BPF_MEM | BPF_H:
+ if (is_ereg(dst_reg) || is_ereg(src_reg))
+ EMIT3(0x66, add_2mod(0x40, dst_reg, src_reg), 0x89);
+ else
+ EMIT2(0x66, 0x89);
+ goto stx;
+ case BPF_STX | BPF_MEM | BPF_W:
+ if (is_ereg(dst_reg) || is_ereg(src_reg))
+ EMIT2(add_2mod(0x40, dst_reg, src_reg), 0x89);
+ else
+ EMIT1(0x89);
+ goto stx;
+ case BPF_STX | BPF_MEM | BPF_DW:
+ EMIT2(add_2mod(0x48, dst_reg, src_reg), 0x89);
+stx: if (is_imm8(insn->off))
+ EMIT2(add_2reg(0x40, dst_reg, src_reg), insn->off);
+ else
+ EMIT1_off32(add_2reg(0x80, dst_reg, src_reg),
+ insn->off);
+ break;
+
+ /* LDX: dst_reg = *(u8*)(src_reg + off) */
+ case BPF_LDX | BPF_MEM | BPF_B:
+ /* Emit 'movzx rax, byte ptr [rax + off]' */
+ EMIT3(add_2mod(0x48, src_reg, dst_reg), 0x0F, 0xB6);
+ goto ldx;
+ case BPF_LDX | BPF_MEM | BPF_H:
+ /* Emit 'movzx rax, word ptr [rax + off]' */
+ EMIT3(add_2mod(0x48, src_reg, dst_reg), 0x0F, 0xB7);
+ goto ldx;
+ case BPF_LDX | BPF_MEM | BPF_W:
+ /* Emit 'mov eax, dword ptr [rax+0x14]' */
+ if (is_ereg(dst_reg) || is_ereg(src_reg))
+ EMIT2(add_2mod(0x40, src_reg, dst_reg), 0x8B);
+ else
+ EMIT1(0x8B);
+ goto ldx;
+ case BPF_LDX | BPF_MEM | BPF_DW:
+ /* Emit 'mov rax, qword ptr [rax+0x14]' */
+ EMIT2(add_2mod(0x48, src_reg, dst_reg), 0x8B);
+ldx: /*
+ * If insn->off == 0 we can save one extra byte, but
+ * special case of x86 R13 which always needs an offset
+ * is not worth the hassle
+ */
+ if (is_imm8(insn->off))
+ EMIT2(add_2reg(0x40, src_reg, dst_reg), insn->off);
+ else
+ EMIT1_off32(add_2reg(0x80, src_reg, dst_reg),
+ insn->off);
+ break;
+
+ /* STX XADD: lock *(u32*)(dst_reg + off) += src_reg */
+ case BPF_STX | BPF_XADD | BPF_W:
+ /* Emit 'lock add dword ptr [rax + off], eax' */
+ if (is_ereg(dst_reg) || is_ereg(src_reg))
+ EMIT3(0xF0, add_2mod(0x40, dst_reg, src_reg), 0x01);
+ else
+ EMIT2(0xF0, 0x01);
+ goto xadd;
+ case BPF_STX | BPF_XADD | BPF_DW:
+ EMIT3(0xF0, add_2mod(0x48, dst_reg, src_reg), 0x01);
+xadd: if (is_imm8(insn->off))
+ EMIT2(add_2reg(0x40, dst_reg, src_reg), insn->off);
+ else
+ EMIT1_off32(add_2reg(0x80, dst_reg, src_reg),
+ insn->off);
+ break;
+
+ /* call */
+ case BPF_JMP | BPF_CALL:
+ func = (u8 *) __bpf_call_base + imm32;
+ jmp_offset = func - (image + addrs[i]);
+ if (!imm32 || !is_simm32(jmp_offset)) {
+ pr_err("unsupported BPF func %d addr %p image %p\n",
+ imm32, func, image);
+ return -EINVAL;
+ }
+ EMIT1_off32(0xE8, jmp_offset);
+ break;
+
+ case BPF_JMP | BPF_TAIL_CALL:
+ emit_bpf_tail_call(&prog);
+ break;
+
+ /* cond jump */
+ case BPF_JMP | BPF_JEQ | BPF_X:
+ case BPF_JMP | BPF_JNE | BPF_X:
+ case BPF_JMP | BPF_JGT | BPF_X:
+ case BPF_JMP | BPF_JLT | BPF_X:
+ case BPF_JMP | BPF_JGE | BPF_X:
+ case BPF_JMP | BPF_JLE | BPF_X:
+ case BPF_JMP | BPF_JSGT | BPF_X:
+ case BPF_JMP | BPF_JSLT | BPF_X:
+ case BPF_JMP | BPF_JSGE | BPF_X:
+ case BPF_JMP | BPF_JSLE | BPF_X:
+ /* cmp dst_reg, src_reg */
+ EMIT3(add_2mod(0x48, dst_reg, src_reg), 0x39,
+ add_2reg(0xC0, dst_reg, src_reg));
+ goto emit_cond_jmp;
+
+ case BPF_JMP | BPF_JSET | BPF_X:
+ /* test dst_reg, src_reg */
+ EMIT3(add_2mod(0x48, dst_reg, src_reg), 0x85,
+ add_2reg(0xC0, dst_reg, src_reg));
+ goto emit_cond_jmp;
+
+ case BPF_JMP | BPF_JSET | BPF_K:
+ /* test dst_reg, imm32 */
+ EMIT1(add_1mod(0x48, dst_reg));
+ EMIT2_off32(0xF7, add_1reg(0xC0, dst_reg), imm32);
+ goto emit_cond_jmp;
+
+ case BPF_JMP | BPF_JEQ | BPF_K:
+ case BPF_JMP | BPF_JNE | BPF_K:
+ case BPF_JMP | BPF_JGT | BPF_K:
+ case BPF_JMP | BPF_JLT | BPF_K:
+ case BPF_JMP | BPF_JGE | BPF_K:
+ case BPF_JMP | BPF_JLE | BPF_K:
+ case BPF_JMP | BPF_JSGT | BPF_K:
+ case BPF_JMP | BPF_JSLT | BPF_K:
+ case BPF_JMP | BPF_JSGE | BPF_K:
+ case BPF_JMP | BPF_JSLE | BPF_K:
+ /* cmp dst_reg, imm8/32 */
+ EMIT1(add_1mod(0x48, dst_reg));
+
+ if (is_imm8(imm32))
+ EMIT3(0x83, add_1reg(0xF8, dst_reg), imm32);
+ else
+ EMIT2_off32(0x81, add_1reg(0xF8, dst_reg), imm32);
+
+emit_cond_jmp: /* Convert BPF opcode to x86 */
+ switch (BPF_OP(insn->code)) {
+ case BPF_JEQ:
+ jmp_cond = X86_JE;
+ break;
+ case BPF_JSET:
+ case BPF_JNE:
+ jmp_cond = X86_JNE;
+ break;
+ case BPF_JGT:
+ /* GT is unsigned '>', JA in x86 */
+ jmp_cond = X86_JA;
+ break;
+ case BPF_JLT:
+ /* LT is unsigned '<', JB in x86 */
+ jmp_cond = X86_JB;
+ break;
+ case BPF_JGE:
+ /* GE is unsigned '>=', JAE in x86 */
+ jmp_cond = X86_JAE;
+ break;
+ case BPF_JLE:
+ /* LE is unsigned '<=', JBE in x86 */
+ jmp_cond = X86_JBE;
+ break;
+ case BPF_JSGT:
+ /* Signed '>', GT in x86 */
+ jmp_cond = X86_JG;
+ break;
+ case BPF_JSLT:
+ /* Signed '<', LT in x86 */
+ jmp_cond = X86_JL;
+ break;
+ case BPF_JSGE:
+ /* Signed '>=', GE in x86 */
+ jmp_cond = X86_JGE;
+ break;
+ case BPF_JSLE:
+ /* Signed '<=', LE in x86 */
+ jmp_cond = X86_JLE;
+ break;
+ default: /* to silence GCC warning */
+ return -EFAULT;
+ }
+ jmp_offset = addrs[i + insn->off] - addrs[i];
+ if (is_imm8(jmp_offset)) {
+ EMIT2(jmp_cond, jmp_offset);
+ } else if (is_simm32(jmp_offset)) {
+ EMIT2_off32(0x0F, jmp_cond + 0x10, jmp_offset);
+ } else {
+ pr_err("cond_jmp gen bug %llx\n", jmp_offset);
+ return -EFAULT;
+ }
+
+ break;
+
+ case BPF_JMP | BPF_JA:
+ if (insn->off == -1)
+ /* -1 jmp instructions will always jump
+ * backwards two bytes. Explicitly handling
+ * this case avoids wasting too many passes
+ * when there are long sequences of replaced
+ * dead code.
+ */
+ jmp_offset = -2;
+ else
+ jmp_offset = addrs[i + insn->off] - addrs[i];
+
+ if (!jmp_offset)
+ /* Optimize out nop jumps */
+ break;
+emit_jmp:
+ if (is_imm8(jmp_offset)) {
+ EMIT2(0xEB, jmp_offset);
+ } else if (is_simm32(jmp_offset)) {
+ EMIT1_off32(0xE9, jmp_offset);
+ } else {
+ pr_err("jmp gen bug %llx\n", jmp_offset);
+ return -EFAULT;
+ }
+ break;
+
+ case BPF_JMP | BPF_EXIT:
+ if (seen_exit) {
+ jmp_offset = ctx->cleanup_addr - addrs[i];
+ goto emit_jmp;
+ }
+ seen_exit = true;
+ /* Update cleanup_addr */
+ ctx->cleanup_addr = proglen;
+ if (!bpf_prog_was_classic(bpf_prog))
+ EMIT1(0x5B); /* get rid of tail_call_cnt */
+ EMIT2(0x41, 0x5F); /* pop r15 */
+ EMIT2(0x41, 0x5E); /* pop r14 */
+ EMIT2(0x41, 0x5D); /* pop r13 */
+ EMIT1(0x5B); /* pop rbx */
+ EMIT1(0xC9); /* leave */
+ EMIT1(0xC3); /* ret */
+ break;
+
+ default:
+ /*
+ * By design x86-64 JIT should support all BPF instructions.
+ * This error will be seen if new instruction was added
+ * to the interpreter, but not to the JIT, or if there is
+ * junk in bpf_prog.
+ */
+ pr_err("bpf_jit: unknown opcode %02x\n", insn->code);
+ return -EINVAL;
+ }
+
+ ilen = prog - temp;
+ if (ilen > BPF_MAX_INSN_SIZE) {
+ pr_err("bpf_jit: fatal insn size error\n");
+ return -EFAULT;
+ }
+
+ if (image) {
+ /*
+ * When populating the image, assert that:
+ *
+ * i) We do not write beyond the allocated space, and
+ * ii) addrs[i] did not change from the prior run, in order
+ * to validate assumptions made for computing branch
+ * displacements.
+ */
+ if (unlikely(proglen + ilen > oldproglen ||
+ proglen + ilen != addrs[i])) {
+ pr_err("bpf_jit: fatal error\n");
+ return -EFAULT;
+ }
+ memcpy(image + proglen, temp, ilen);
+ }
+ proglen += ilen;
+ addrs[i] = proglen;
+ prog = temp;
+ }
+ return proglen;
+}
+
+struct x64_jit_data {
+ struct bpf_binary_header *header;
+ int *addrs;
+ u8 *image;
+ int proglen;
+ struct jit_context ctx;
+};
+
+struct bpf_prog *bpf_int_jit_compile(struct bpf_prog *prog)
+{
+ struct bpf_binary_header *header = NULL;
+ struct bpf_prog *tmp, *orig_prog = prog;
+ struct x64_jit_data *jit_data;
+ int proglen, oldproglen = 0;
+ struct jit_context ctx = {};
+ bool tmp_blinded = false;
+ bool extra_pass = false;
+ u8 *image = NULL;
+ int *addrs;
+ int pass;
+ int i;
+
+ if (!prog->jit_requested)
+ return orig_prog;
+
+ tmp = bpf_jit_blind_constants(prog);
+ /*
+ * If blinding was requested and we failed during blinding,
+ * we must fall back to the interpreter.
+ */
+ if (IS_ERR(tmp))
+ return orig_prog;
+ if (tmp != prog) {
+ tmp_blinded = true;
+ prog = tmp;
+ }
+
+ jit_data = prog->aux->jit_data;
+ if (!jit_data) {
+ jit_data = kzalloc(sizeof(*jit_data), GFP_KERNEL);
+ if (!jit_data) {
+ prog = orig_prog;
+ goto out;
+ }
+ prog->aux->jit_data = jit_data;
+ }
+ addrs = jit_data->addrs;
+ if (addrs) {
+ ctx = jit_data->ctx;
+ oldproglen = jit_data->proglen;
+ image = jit_data->image;
+ header = jit_data->header;
+ extra_pass = true;
+ goto skip_init_addrs;
+ }
+ addrs = kmalloc_array(prog->len, sizeof(*addrs), GFP_KERNEL);
+ if (!addrs) {
+ prog = orig_prog;
+ goto out_addrs;
+ }
+
+ /*
+ * 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 < prog->len; i++) {
+ proglen += 64;
+ addrs[i] = proglen;
+ }
+ ctx.cleanup_addr = proglen;
+skip_init_addrs:
+
+ /*
+ * JITed image shrinks with every pass and the loop iterates
+ * until the image stops shrinking. Very large BPF programs
+ * may converge on the last pass. In such case do one more
+ * pass to emit the final image.
+ */
+ for (pass = 0; pass < 20 || image; pass++) {
+ proglen = do_jit(prog, addrs, image, oldproglen, &ctx);
+ if (proglen <= 0) {
+out_image:
+ image = NULL;
+ if (header)
+ bpf_jit_binary_free(header);
+ prog = orig_prog;
+ goto out_addrs;
+ }
+ if (image) {
+ if (proglen != oldproglen) {
+ pr_err("bpf_jit: proglen=%d != oldproglen=%d\n",
+ proglen, oldproglen);
+ goto out_image;
+ }
+ break;
+ }
+ if (proglen == oldproglen) {
+ header = bpf_jit_binary_alloc(proglen, &image,
+ 1, jit_fill_hole);
+ if (!header) {
+ prog = orig_prog;
+ goto out_addrs;
+ }
+ }
+ oldproglen = proglen;
+ cond_resched();
+ }
+
+ if (bpf_jit_enable > 1)
+ bpf_jit_dump(prog->len, proglen, pass + 1, image);
+
+ if (image) {
+ if (!prog->is_func || extra_pass) {
+ bpf_jit_binary_lock_ro(header);
+ } else {
+ jit_data->addrs = addrs;
+ jit_data->ctx = ctx;
+ jit_data->proglen = proglen;
+ jit_data->image = image;
+ jit_data->header = header;
+ }
+ prog->bpf_func = (void *)image;
+ prog->jited = 1;
+ prog->jited_len = proglen;
+ } else {
+ prog = orig_prog;
+ }
+
+ if (!image || !prog->is_func || extra_pass) {
+out_addrs:
+ kfree(addrs);
+ kfree(jit_data);
+ prog->aux->jit_data = NULL;
+ }
+out:
+ if (tmp_blinded)
+ bpf_jit_prog_release_other(prog, prog == orig_prog ?
+ tmp : orig_prog);
+ return prog;
+}
generated by cgit v1.2.3 (git 2.39.1) at 2024-12-01 00:12:59 +0000