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authorDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-07 18:49:45 +0000
committerDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-07 18:49:45 +0000
commit2c3c1048746a4622d8c89a29670120dc8fab93c4 (patch)
tree848558de17fb3008cdf4d861b01ac7781903ce39 /arch/x86/net/bpf_jit_comp.c
parentInitial commit. (diff)
downloadlinux-2c3c1048746a4622d8c89a29670120dc8fab93c4.tar.xz
linux-2c3c1048746a4622d8c89a29670120dc8fab93c4.zip
Adding upstream version 6.1.76.upstream/6.1.76
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'arch/x86/net/bpf_jit_comp.c')
-rw-r--r--arch/x86/net/bpf_jit_comp.c2597
1 files changed, 2597 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..b69aee624
--- /dev/null
+++ b/arch/x86/net/bpf_jit_comp.c
@@ -0,0 +1,2597 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * BPF JIT compiler
+ *
+ * Copyright (C) 2011-2013 Eric Dumazet (eric.dumazet@gmail.com)
+ * Copyright (c) 2011-2014 PLUMgrid, http://plumgrid.com
+ */
+#include <linux/netdevice.h>
+#include <linux/filter.h>
+#include <linux/if_vlan.h>
+#include <linux/bpf.h>
+#include <linux/memory.h>
+#include <linux/sort.h>
+#include <asm/extable.h>
+#include <asm/set_memory.h>
+#include <asm/nospec-branch.h>
+#include <asm/text-patching.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); } 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)
+
+#ifdef CONFIG_X86_KERNEL_IBT
+#define EMIT_ENDBR() EMIT(gen_endbr(), 4)
+#else
+#define EMIT_ENDBR()
+#endif
+
+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)
+#define X86_REG_R9 (MAX_BPF_JIT_REG + 2)
+
+/*
+ * 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.
+ *
+ * x86-64 register R9 is not used by BPF programs, but can be used by BPF
+ * trampoline. 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 */
+ [X86_REG_R9] = 1, /* R9 register, 6th function argument */
+};
+
+static const int reg2pt_regs[] = {
+ [BPF_REG_0] = offsetof(struct pt_regs, ax),
+ [BPF_REG_1] = offsetof(struct pt_regs, di),
+ [BPF_REG_2] = offsetof(struct pt_regs, si),
+ [BPF_REG_3] = offsetof(struct pt_regs, dx),
+ [BPF_REG_4] = offsetof(struct pt_regs, cx),
+ [BPF_REG_5] = offsetof(struct pt_regs, r8),
+ [BPF_REG_6] = offsetof(struct pt_regs, bx),
+ [BPF_REG_7] = offsetof(struct pt_regs, r13),
+ [BPF_REG_8] = offsetof(struct pt_regs, r14),
+ [BPF_REG_9] = offsetof(struct pt_regs, r15),
+};
+
+/*
+ * 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(X86_REG_R9) |
+ 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);
+}
+
+/* Some 1-byte opcodes for binary ALU operations */
+static u8 simple_alu_opcodes[] = {
+ [BPF_ADD] = 0x01,
+ [BPF_SUB] = 0x29,
+ [BPF_AND] = 0x21,
+ [BPF_OR] = 0x09,
+ [BPF_XOR] = 0x31,
+ [BPF_LSH] = 0xE0,
+ [BPF_RSH] = 0xE8,
+ [BPF_ARSH] = 0xF8,
+};
+
+static void jit_fill_hole(void *area, unsigned int size)
+{
+ /* Fill whole space with INT3 instructions */
+ memset(area, 0xcc, size);
+}
+
+int bpf_arch_text_invalidate(void *dst, size_t len)
+{
+ return IS_ERR_OR_NULL(text_poke_set(dst, 0xcc, len));
+}
+
+struct jit_context {
+ int cleanup_addr; /* Epilogue code offset */
+
+ /*
+ * Program specific offsets of labels in the code; these rely on the
+ * JIT doing at least 2 passes, recording the position on the first
+ * pass, only to generate the correct offset on the second pass.
+ */
+ int tail_call_direct_label;
+ int tail_call_indirect_label;
+};
+
+/* Maximum number of bytes emitted while JITing one eBPF insn */
+#define BPF_MAX_INSN_SIZE 128
+#define BPF_INSN_SAFETY 64
+
+/* Number of bytes emit_patch() needs to generate instructions */
+#define X86_PATCH_SIZE 5
+/* Number of bytes that will be skipped on tailcall */
+#define X86_TAIL_CALL_OFFSET (11 + ENDBR_INSN_SIZE)
+
+static void push_callee_regs(u8 **pprog, bool *callee_regs_used)
+{
+ u8 *prog = *pprog;
+
+ if (callee_regs_used[0])
+ EMIT1(0x53); /* push rbx */
+ if (callee_regs_used[1])
+ EMIT2(0x41, 0x55); /* push r13 */
+ if (callee_regs_used[2])
+ EMIT2(0x41, 0x56); /* push r14 */
+ if (callee_regs_used[3])
+ EMIT2(0x41, 0x57); /* push r15 */
+ *pprog = prog;
+}
+
+static void pop_callee_regs(u8 **pprog, bool *callee_regs_used)
+{
+ u8 *prog = *pprog;
+
+ if (callee_regs_used[3])
+ EMIT2(0x41, 0x5F); /* pop r15 */
+ if (callee_regs_used[2])
+ EMIT2(0x41, 0x5E); /* pop r14 */
+ if (callee_regs_used[1])
+ EMIT2(0x41, 0x5D); /* pop r13 */
+ if (callee_regs_used[0])
+ EMIT1(0x5B); /* pop rbx */
+ *pprog = prog;
+}
+
+/*
+ * Emit x86-64 prologue code for BPF program.
+ * bpf_tail_call helper will skip the first X86_TAIL_CALL_OFFSET bytes
+ * while jumping to another program
+ */
+static void emit_prologue(u8 **pprog, u32 stack_depth, bool ebpf_from_cbpf,
+ bool tail_call_reachable, bool is_subprog)
+{
+ u8 *prog = *pprog;
+
+ /* BPF trampoline can be made to work without these nops,
+ * but let's waste 5 bytes for now and optimize later
+ */
+ EMIT_ENDBR();
+ memcpy(prog, x86_nops[5], X86_PATCH_SIZE);
+ prog += X86_PATCH_SIZE;
+ if (!ebpf_from_cbpf) {
+ if (tail_call_reachable && !is_subprog)
+ EMIT2(0x31, 0xC0); /* xor eax, eax */
+ else
+ EMIT2(0x66, 0x90); /* nop2 */
+ }
+ EMIT1(0x55); /* push rbp */
+ EMIT3(0x48, 0x89, 0xE5); /* mov rbp, rsp */
+
+ /* X86_TAIL_CALL_OFFSET is here */
+ EMIT_ENDBR();
+
+ /* sub rsp, rounded_stack_depth */
+ if (stack_depth)
+ EMIT3_off32(0x48, 0x81, 0xEC, round_up(stack_depth, 8));
+ if (tail_call_reachable)
+ EMIT1(0x50); /* push rax */
+ *pprog = prog;
+}
+
+static int emit_patch(u8 **pprog, void *func, void *ip, u8 opcode)
+{
+ u8 *prog = *pprog;
+ s64 offset;
+
+ offset = func - (ip + X86_PATCH_SIZE);
+ if (!is_simm32(offset)) {
+ pr_err("Target call %p is out of range\n", func);
+ return -ERANGE;
+ }
+ EMIT1_off32(opcode, offset);
+ *pprog = prog;
+ return 0;
+}
+
+static int emit_call(u8 **pprog, void *func, void *ip)
+{
+ return emit_patch(pprog, func, ip, 0xE8);
+}
+
+static int emit_jump(u8 **pprog, void *func, void *ip)
+{
+ return emit_patch(pprog, func, ip, 0xE9);
+}
+
+static int __bpf_arch_text_poke(void *ip, enum bpf_text_poke_type t,
+ void *old_addr, void *new_addr)
+{
+ const u8 *nop_insn = x86_nops[5];
+ u8 old_insn[X86_PATCH_SIZE];
+ u8 new_insn[X86_PATCH_SIZE];
+ u8 *prog;
+ int ret;
+
+ memcpy(old_insn, nop_insn, X86_PATCH_SIZE);
+ if (old_addr) {
+ prog = old_insn;
+ ret = t == BPF_MOD_CALL ?
+ emit_call(&prog, old_addr, ip) :
+ emit_jump(&prog, old_addr, ip);
+ if (ret)
+ return ret;
+ }
+
+ memcpy(new_insn, nop_insn, X86_PATCH_SIZE);
+ if (new_addr) {
+ prog = new_insn;
+ ret = t == BPF_MOD_CALL ?
+ emit_call(&prog, new_addr, ip) :
+ emit_jump(&prog, new_addr, ip);
+ if (ret)
+ return ret;
+ }
+
+ ret = -EBUSY;
+ mutex_lock(&text_mutex);
+ if (memcmp(ip, old_insn, X86_PATCH_SIZE))
+ goto out;
+ ret = 1;
+ if (memcmp(ip, new_insn, X86_PATCH_SIZE)) {
+ text_poke_bp(ip, new_insn, X86_PATCH_SIZE, NULL);
+ ret = 0;
+ }
+out:
+ mutex_unlock(&text_mutex);
+ return ret;
+}
+
+int bpf_arch_text_poke(void *ip, enum bpf_text_poke_type t,
+ void *old_addr, void *new_addr)
+{
+ if (!is_kernel_text((long)ip) &&
+ !is_bpf_text_address((long)ip))
+ /* BPF poking in modules is not supported */
+ return -EINVAL;
+
+ /*
+ * See emit_prologue(), for IBT builds the trampoline hook is preceded
+ * with an ENDBR instruction.
+ */
+ if (is_endbr(*(u32 *)ip))
+ ip += ENDBR_INSN_SIZE;
+
+ return __bpf_arch_text_poke(ip, t, old_addr, new_addr);
+}
+
+#define EMIT_LFENCE() EMIT3(0x0F, 0xAE, 0xE8)
+
+static void emit_indirect_jump(u8 **pprog, int reg, u8 *ip)
+{
+ u8 *prog = *pprog;
+
+ if (cpu_feature_enabled(X86_FEATURE_RETPOLINE_LFENCE)) {
+ EMIT_LFENCE();
+ EMIT2(0xFF, 0xE0 + reg);
+ } else if (cpu_feature_enabled(X86_FEATURE_RETPOLINE)) {
+ OPTIMIZER_HIDE_VAR(reg);
+ emit_jump(&prog, &__x86_indirect_thunk_array[reg], ip);
+ } else {
+ EMIT2(0xFF, 0xE0 + reg); /* jmp *%\reg */
+ if (IS_ENABLED(CONFIG_RETPOLINE) || IS_ENABLED(CONFIG_SLS))
+ EMIT1(0xCC); /* int3 */
+ }
+
+ *pprog = prog;
+}
+
+static void emit_return(u8 **pprog, u8 *ip)
+{
+ u8 *prog = *pprog;
+
+ if (cpu_feature_enabled(X86_FEATURE_RETHUNK)) {
+ emit_jump(&prog, &__x86_return_thunk, ip);
+ } else {
+ EMIT1(0xC3); /* ret */
+ if (IS_ENABLED(CONFIG_SLS))
+ EMIT1(0xCC); /* int3 */
+ }
+
+ *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_indirect(u8 **pprog, bool *callee_regs_used,
+ u32 stack_depth, u8 *ip,
+ struct jit_context *ctx)
+{
+ int tcc_off = -4 - round_up(stack_depth, 8);
+ u8 *prog = *pprog, *start = *pprog;
+ int offset;
+
+ /*
+ * 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));
+
+ offset = ctx->tail_call_indirect_label - (prog + 2 - start);
+ EMIT2(X86_JBE, offset); /* jbe out */
+
+ /*
+ * if (tail_call_cnt++ >= MAX_TAIL_CALL_CNT)
+ * goto out;
+ */
+ EMIT2_off32(0x8B, 0x85, tcc_off); /* mov eax, dword ptr [rbp - tcc_off] */
+ EMIT3(0x83, 0xF8, MAX_TAIL_CALL_CNT); /* cmp eax, MAX_TAIL_CALL_CNT */
+
+ offset = ctx->tail_call_indirect_label - (prog + 2 - start);
+ EMIT2(X86_JAE, offset); /* jae out */
+ EMIT3(0x83, 0xC0, 0x01); /* add eax, 1 */
+ EMIT2_off32(0x89, 0x85, tcc_off); /* mov dword ptr [rbp - tcc_off], eax */
+
+ /* prog = array->ptrs[index]; */
+ EMIT4_off32(0x48, 0x8B, 0x8C, 0xD6, /* mov rcx, [rsi + rdx * 8 + offsetof(...)] */
+ offsetof(struct bpf_array, ptrs));
+
+ /*
+ * if (prog == NULL)
+ * goto out;
+ */
+ EMIT3(0x48, 0x85, 0xC9); /* test rcx,rcx */
+
+ offset = ctx->tail_call_indirect_label - (prog + 2 - start);
+ EMIT2(X86_JE, offset); /* je out */
+
+ pop_callee_regs(&prog, callee_regs_used);
+
+ EMIT1(0x58); /* pop rax */
+ if (stack_depth)
+ EMIT3_off32(0x48, 0x81, 0xC4, /* add rsp, sd */
+ round_up(stack_depth, 8));
+
+ /* goto *(prog->bpf_func + X86_TAIL_CALL_OFFSET); */
+ EMIT4(0x48, 0x8B, 0x49, /* mov rcx, qword ptr [rcx + 32] */
+ offsetof(struct bpf_prog, bpf_func));
+ EMIT4(0x48, 0x83, 0xC1, /* add rcx, X86_TAIL_CALL_OFFSET */
+ X86_TAIL_CALL_OFFSET);
+ /*
+ * Now we're ready to jump into next BPF program
+ * rdi == ctx (1st arg)
+ * rcx == prog->bpf_func + X86_TAIL_CALL_OFFSET
+ */
+ emit_indirect_jump(&prog, 1 /* rcx */, ip + (prog - start));
+
+ /* out: */
+ ctx->tail_call_indirect_label = prog - start;
+ *pprog = prog;
+}
+
+static void emit_bpf_tail_call_direct(struct bpf_jit_poke_descriptor *poke,
+ u8 **pprog, u8 *ip,
+ bool *callee_regs_used, u32 stack_depth,
+ struct jit_context *ctx)
+{
+ int tcc_off = -4 - round_up(stack_depth, 8);
+ u8 *prog = *pprog, *start = *pprog;
+ int offset;
+
+ /*
+ * if (tail_call_cnt++ >= MAX_TAIL_CALL_CNT)
+ * goto out;
+ */
+ EMIT2_off32(0x8B, 0x85, tcc_off); /* mov eax, dword ptr [rbp - tcc_off] */
+ EMIT3(0x83, 0xF8, MAX_TAIL_CALL_CNT); /* cmp eax, MAX_TAIL_CALL_CNT */
+
+ offset = ctx->tail_call_direct_label - (prog + 2 - start);
+ EMIT2(X86_JAE, offset); /* jae out */
+ EMIT3(0x83, 0xC0, 0x01); /* add eax, 1 */
+ EMIT2_off32(0x89, 0x85, tcc_off); /* mov dword ptr [rbp - tcc_off], eax */
+
+ poke->tailcall_bypass = ip + (prog - start);
+ poke->adj_off = X86_TAIL_CALL_OFFSET;
+ poke->tailcall_target = ip + ctx->tail_call_direct_label - X86_PATCH_SIZE;
+ poke->bypass_addr = (u8 *)poke->tailcall_target + X86_PATCH_SIZE;
+
+ emit_jump(&prog, (u8 *)poke->tailcall_target + X86_PATCH_SIZE,
+ poke->tailcall_bypass);
+
+ pop_callee_regs(&prog, callee_regs_used);
+ EMIT1(0x58); /* pop rax */
+ if (stack_depth)
+ EMIT3_off32(0x48, 0x81, 0xC4, round_up(stack_depth, 8));
+
+ memcpy(prog, x86_nops[5], X86_PATCH_SIZE);
+ prog += X86_PATCH_SIZE;
+
+ /* out: */
+ ctx->tail_call_direct_label = prog - start;
+
+ *pprog = prog;
+}
+
+static void bpf_tail_call_direct_fixup(struct bpf_prog *prog)
+{
+ struct bpf_jit_poke_descriptor *poke;
+ struct bpf_array *array;
+ struct bpf_prog *target;
+ int i, ret;
+
+ for (i = 0; i < prog->aux->size_poke_tab; i++) {
+ poke = &prog->aux->poke_tab[i];
+ if (poke->aux && poke->aux != prog->aux)
+ continue;
+
+ WARN_ON_ONCE(READ_ONCE(poke->tailcall_target_stable));
+
+ if (poke->reason != BPF_POKE_REASON_TAIL_CALL)
+ continue;
+
+ array = container_of(poke->tail_call.map, struct bpf_array, map);
+ mutex_lock(&array->aux->poke_mutex);
+ target = array->ptrs[poke->tail_call.key];
+ if (target) {
+ ret = __bpf_arch_text_poke(poke->tailcall_target,
+ BPF_MOD_JUMP, NULL,
+ (u8 *)target->bpf_func +
+ poke->adj_off);
+ BUG_ON(ret < 0);
+ ret = __bpf_arch_text_poke(poke->tailcall_bypass,
+ BPF_MOD_JUMP,
+ (u8 *)poke->tailcall_target +
+ X86_PATCH_SIZE, NULL);
+ BUG_ON(ret < 0);
+ }
+ WRITE_ONCE(poke->tailcall_target_stable, true);
+ mutex_unlock(&array->aux->poke_mutex);
+ }
+}
+
+static void emit_mov_imm32(u8 **pprog, bool sign_propagate,
+ u32 dst_reg, const u32 imm32)
+{
+ u8 *prog = *pprog;
+ u8 b1, b2, b3;
+
+ /*
+ * 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;
+
+ 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;
+
+ 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;
+}
+
+/* Emit the suffix (ModR/M etc) for addressing *(ptr_reg + off) and val_reg */
+static void emit_insn_suffix(u8 **pprog, u32 ptr_reg, u32 val_reg, int off)
+{
+ u8 *prog = *pprog;
+
+ if (is_imm8(off)) {
+ /* 1-byte signed displacement.
+ *
+ * If off == 0 we could skip this and save one extra byte, but
+ * special case of x86 R13 which always needs an offset is not
+ * worth the hassle
+ */
+ EMIT2(add_2reg(0x40, ptr_reg, val_reg), off);
+ } else {
+ /* 4-byte signed displacement */
+ EMIT1_off32(add_2reg(0x80, ptr_reg, val_reg), off);
+ }
+ *pprog = prog;
+}
+
+/*
+ * Emit a REX byte if it will be necessary to address these registers
+ */
+static void maybe_emit_mod(u8 **pprog, u32 dst_reg, u32 src_reg, bool is64)
+{
+ u8 *prog = *pprog;
+
+ if (is64)
+ 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));
+ *pprog = prog;
+}
+
+/*
+ * Similar version of maybe_emit_mod() for a single register
+ */
+static void maybe_emit_1mod(u8 **pprog, u32 reg, bool is64)
+{
+ u8 *prog = *pprog;
+
+ if (is64)
+ EMIT1(add_1mod(0x48, reg));
+ else if (is_ereg(reg))
+ EMIT1(add_1mod(0x40, reg));
+ *pprog = prog;
+}
+
+/* LDX: dst_reg = *(u8*)(src_reg + off) */
+static void emit_ldx(u8 **pprog, u32 size, u32 dst_reg, u32 src_reg, int off)
+{
+ u8 *prog = *pprog;
+
+ switch (size) {
+ case BPF_B:
+ /* Emit 'movzx rax, byte ptr [rax + off]' */
+ EMIT3(add_2mod(0x48, src_reg, dst_reg), 0x0F, 0xB6);
+ break;
+ case BPF_H:
+ /* Emit 'movzx rax, word ptr [rax + off]' */
+ EMIT3(add_2mod(0x48, src_reg, dst_reg), 0x0F, 0xB7);
+ break;
+ case 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);
+ break;
+ case BPF_DW:
+ /* Emit 'mov rax, qword ptr [rax+0x14]' */
+ EMIT2(add_2mod(0x48, src_reg, dst_reg), 0x8B);
+ break;
+ }
+ emit_insn_suffix(&prog, src_reg, dst_reg, off);
+ *pprog = prog;
+}
+
+/* STX: *(u8*)(dst_reg + off) = src_reg */
+static void emit_stx(u8 **pprog, u32 size, u32 dst_reg, u32 src_reg, int off)
+{
+ u8 *prog = *pprog;
+
+ switch (size) {
+ case 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);
+ break;
+ case 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);
+ break;
+ case BPF_W:
+ if (is_ereg(dst_reg) || is_ereg(src_reg))
+ EMIT2(add_2mod(0x40, dst_reg, src_reg), 0x89);
+ else
+ EMIT1(0x89);
+ break;
+ case BPF_DW:
+ EMIT2(add_2mod(0x48, dst_reg, src_reg), 0x89);
+ break;
+ }
+ emit_insn_suffix(&prog, dst_reg, src_reg, off);
+ *pprog = prog;
+}
+
+static int emit_atomic(u8 **pprog, u8 atomic_op,
+ u32 dst_reg, u32 src_reg, s16 off, u8 bpf_size)
+{
+ u8 *prog = *pprog;
+
+ EMIT1(0xF0); /* lock prefix */
+
+ maybe_emit_mod(&prog, dst_reg, src_reg, bpf_size == BPF_DW);
+
+ /* emit opcode */
+ switch (atomic_op) {
+ case BPF_ADD:
+ case BPF_AND:
+ case BPF_OR:
+ case BPF_XOR:
+ /* lock *(u32/u64*)(dst_reg + off) <op>= src_reg */
+ EMIT1(simple_alu_opcodes[atomic_op]);
+ break;
+ case BPF_ADD | BPF_FETCH:
+ /* src_reg = atomic_fetch_add(dst_reg + off, src_reg); */
+ EMIT2(0x0F, 0xC1);
+ break;
+ case BPF_XCHG:
+ /* src_reg = atomic_xchg(dst_reg + off, src_reg); */
+ EMIT1(0x87);
+ break;
+ case BPF_CMPXCHG:
+ /* r0 = atomic_cmpxchg(dst_reg + off, r0, src_reg); */
+ EMIT2(0x0F, 0xB1);
+ break;
+ default:
+ pr_err("bpf_jit: unknown atomic opcode %02x\n", atomic_op);
+ return -EFAULT;
+ }
+
+ emit_insn_suffix(&prog, dst_reg, src_reg, off);
+
+ *pprog = prog;
+ return 0;
+}
+
+bool ex_handler_bpf(const struct exception_table_entry *x, struct pt_regs *regs)
+{
+ u32 reg = x->fixup >> 8;
+
+ /* jump over faulting load and clear dest register */
+ *(unsigned long *)((void *)regs + reg) = 0;
+ regs->ip += x->fixup & 0xff;
+ return true;
+}
+
+static void detect_reg_usage(struct bpf_insn *insn, int insn_cnt,
+ bool *regs_used, bool *tail_call_seen)
+{
+ int i;
+
+ for (i = 1; i <= insn_cnt; i++, insn++) {
+ if (insn->code == (BPF_JMP | BPF_TAIL_CALL))
+ *tail_call_seen = true;
+ if (insn->dst_reg == BPF_REG_6 || insn->src_reg == BPF_REG_6)
+ regs_used[0] = true;
+ if (insn->dst_reg == BPF_REG_7 || insn->src_reg == BPF_REG_7)
+ regs_used[1] = true;
+ if (insn->dst_reg == BPF_REG_8 || insn->src_reg == BPF_REG_8)
+ regs_used[2] = true;
+ if (insn->dst_reg == BPF_REG_9 || insn->src_reg == BPF_REG_9)
+ regs_used[3] = true;
+ }
+}
+
+static void emit_nops(u8 **pprog, int len)
+{
+ u8 *prog = *pprog;
+ int i, noplen;
+
+ while (len > 0) {
+ noplen = len;
+
+ if (noplen > ASM_NOP_MAX)
+ noplen = ASM_NOP_MAX;
+
+ for (i = 0; i < noplen; i++)
+ EMIT1(x86_nops[noplen][i]);
+ len -= noplen;
+ }
+
+ *pprog = prog;
+}
+
+#define INSN_SZ_DIFF (((addrs[i] - addrs[i - 1]) - (prog - temp)))
+
+/* mov rax, qword ptr [rbp - rounded_stack_depth - 8] */
+#define RESTORE_TAIL_CALL_CNT(stack) \
+ EMIT3_off32(0x48, 0x8B, 0x85, -round_up(stack, 8) - 8)
+
+static int do_jit(struct bpf_prog *bpf_prog, int *addrs, u8 *image, u8 *rw_image,
+ int oldproglen, struct jit_context *ctx, bool jmp_padding)
+{
+ bool tail_call_reachable = bpf_prog->aux->tail_call_reachable;
+ struct bpf_insn *insn = bpf_prog->insnsi;
+ bool callee_regs_used[4] = {};
+ int insn_cnt = bpf_prog->len;
+ bool tail_call_seen = false;
+ bool seen_exit = false;
+ u8 temp[BPF_MAX_INSN_SIZE + BPF_INSN_SAFETY];
+ int i, excnt = 0;
+ int ilen, proglen = 0;
+ u8 *prog = temp;
+ int err;
+
+ detect_reg_usage(insn, insn_cnt, callee_regs_used,
+ &tail_call_seen);
+
+ /* tail call's presence in current prog implies it is reachable */
+ tail_call_reachable |= tail_call_seen;
+
+ emit_prologue(&prog, bpf_prog->aux->stack_depth,
+ bpf_prog_was_classic(bpf_prog), tail_call_reachable,
+ bpf_prog->aux->func_idx != 0);
+ push_callee_regs(&prog, callee_regs_used);
+
+ ilen = prog - temp;
+ if (rw_image)
+ memcpy(rw_image + proglen, temp, ilen);
+ proglen += ilen;
+ addrs[0] = proglen;
+ prog = temp;
+
+ for (i = 1; 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;
+ u8 *start_of_ldx;
+ s64 jmp_offset;
+ u8 jmp_cond;
+ u8 *func;
+ int nops;
+
+ 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:
+ maybe_emit_mod(&prog, dst_reg, src_reg,
+ BPF_CLASS(insn->code) == BPF_ALU64);
+ b2 = simple_alu_opcodes[BPF_OP(insn->code)];
+ 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:
+ maybe_emit_1mod(&prog, dst_reg,
+ BPF_CLASS(insn->code) == BPF_ALU64);
+ 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:
+ maybe_emit_1mod(&prog, dst_reg,
+ BPF_CLASS(insn->code) == BPF_ALU64);
+
+ /*
+ * 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: {
+ 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 */
+
+ if (BPF_SRC(insn->code) == BPF_X) {
+ if (src_reg == BPF_REG_0 ||
+ src_reg == BPF_REG_3) {
+ /* mov r11, src_reg */
+ EMIT_mov(AUX_REG, src_reg);
+ src_reg = AUX_REG;
+ }
+ } else {
+ /* mov r11, imm32 */
+ EMIT3_off32(0x49, 0xC7, 0xC3, imm32);
+ src_reg = AUX_REG;
+ }
+
+ if (dst_reg != BPF_REG_0)
+ /* mov rax, dst_reg */
+ emit_mov_reg(&prog, is64, BPF_REG_0, dst_reg);
+
+ /*
+ * xor edx, edx
+ * equivalent to 'xor rdx, rdx', but one byte less
+ */
+ EMIT2(0x31, 0xd2);
+
+ /* div src_reg */
+ maybe_emit_1mod(&prog, src_reg, is64);
+ EMIT2(0xF7, add_1reg(0xF0, src_reg));
+
+ if (BPF_OP(insn->code) == BPF_MOD &&
+ dst_reg != BPF_REG_3)
+ /* mov dst_reg, rdx */
+ emit_mov_reg(&prog, is64, dst_reg, BPF_REG_3);
+ else if (BPF_OP(insn->code) == BPF_DIV &&
+ dst_reg != BPF_REG_0)
+ /* mov dst_reg, rax */
+ emit_mov_reg(&prog, is64, dst_reg, BPF_REG_0);
+
+ if (dst_reg != BPF_REG_3)
+ EMIT1(0x5A); /* pop rdx */
+ if (dst_reg != BPF_REG_0)
+ EMIT1(0x58); /* pop rax */
+ break;
+ }
+
+ case BPF_ALU | BPF_MUL | BPF_K:
+ case BPF_ALU64 | BPF_MUL | BPF_K:
+ maybe_emit_mod(&prog, dst_reg, dst_reg,
+ BPF_CLASS(insn->code) == BPF_ALU64);
+
+ if (is_imm8(imm32))
+ /* imul dst_reg, dst_reg, imm8 */
+ EMIT3(0x6B, add_2reg(0xC0, dst_reg, dst_reg),
+ imm32);
+ else
+ /* imul dst_reg, dst_reg, imm32 */
+ EMIT2_off32(0x69,
+ add_2reg(0xC0, dst_reg, dst_reg),
+ imm32);
+ break;
+
+ case BPF_ALU | BPF_MUL | BPF_X:
+ case BPF_ALU64 | BPF_MUL | BPF_X:
+ maybe_emit_mod(&prog, src_reg, dst_reg,
+ BPF_CLASS(insn->code) == BPF_ALU64);
+
+ /* imul dst_reg, src_reg */
+ EMIT3(0x0F, 0xAF, add_2reg(0xC0, src_reg, dst_reg));
+ 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:
+ maybe_emit_1mod(&prog, dst_reg,
+ BPF_CLASS(insn->code) == BPF_ALU64);
+
+ b3 = simple_alu_opcodes[BPF_OP(insn->code)];
+ 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 */
+ maybe_emit_1mod(&prog, dst_reg,
+ BPF_CLASS(insn->code) == BPF_ALU64);
+
+ b3 = simple_alu_opcodes[BPF_OP(insn->code)];
+ 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();
+ 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:
+ case BPF_STX | BPF_MEM | BPF_H:
+ case BPF_STX | BPF_MEM | BPF_W:
+ case BPF_STX | BPF_MEM | BPF_DW:
+ emit_stx(&prog, BPF_SIZE(insn->code), dst_reg, src_reg, insn->off);
+ break;
+
+ /* LDX: dst_reg = *(u8*)(src_reg + off) */
+ case BPF_LDX | BPF_MEM | BPF_B:
+ case BPF_LDX | BPF_PROBE_MEM | BPF_B:
+ case BPF_LDX | BPF_MEM | BPF_H:
+ case BPF_LDX | BPF_PROBE_MEM | BPF_H:
+ case BPF_LDX | BPF_MEM | BPF_W:
+ case BPF_LDX | BPF_PROBE_MEM | BPF_W:
+ case BPF_LDX | BPF_MEM | BPF_DW:
+ case BPF_LDX | BPF_PROBE_MEM | BPF_DW:
+ if (BPF_MODE(insn->code) == BPF_PROBE_MEM) {
+ /* Though the verifier prevents negative insn->off in BPF_PROBE_MEM
+ * add abs(insn->off) to the limit to make sure that negative
+ * offset won't be an issue.
+ * insn->off is s16, so it won't affect valid pointers.
+ */
+ u64 limit = TASK_SIZE_MAX + PAGE_SIZE + abs(insn->off);
+ u8 *end_of_jmp1, *end_of_jmp2;
+
+ /* Conservatively check that src_reg + insn->off is a kernel address:
+ * 1. src_reg + insn->off >= limit
+ * 2. src_reg + insn->off doesn't become small positive.
+ * Cannot do src_reg + insn->off >= limit in one branch,
+ * since it needs two spare registers, but JIT has only one.
+ */
+
+ /* movabsq r11, limit */
+ EMIT2(add_1mod(0x48, AUX_REG), add_1reg(0xB8, AUX_REG));
+ EMIT((u32)limit, 4);
+ EMIT(limit >> 32, 4);
+ /* cmp src_reg, r11 */
+ maybe_emit_mod(&prog, src_reg, AUX_REG, true);
+ EMIT2(0x39, add_2reg(0xC0, src_reg, AUX_REG));
+ /* if unsigned '<' goto end_of_jmp2 */
+ EMIT2(X86_JB, 0);
+ end_of_jmp1 = prog;
+
+ /* mov r11, src_reg */
+ emit_mov_reg(&prog, true, AUX_REG, src_reg);
+ /* add r11, insn->off */
+ maybe_emit_1mod(&prog, AUX_REG, true);
+ EMIT2_off32(0x81, add_1reg(0xC0, AUX_REG), insn->off);
+ /* jmp if not carry to start_of_ldx
+ * Otherwise ERR_PTR(-EINVAL) + 128 will be the user addr
+ * that has to be rejected.
+ */
+ EMIT2(0x73 /* JNC */, 0);
+ end_of_jmp2 = prog;
+
+ /* xor dst_reg, dst_reg */
+ emit_mov_imm32(&prog, false, dst_reg, 0);
+ /* jmp byte_after_ldx */
+ EMIT2(0xEB, 0);
+
+ /* populate jmp_offset for JB above to jump to xor dst_reg */
+ end_of_jmp1[-1] = end_of_jmp2 - end_of_jmp1;
+ /* populate jmp_offset for JNC above to jump to start_of_ldx */
+ start_of_ldx = prog;
+ end_of_jmp2[-1] = start_of_ldx - end_of_jmp2;
+ }
+ emit_ldx(&prog, BPF_SIZE(insn->code), dst_reg, src_reg, insn->off);
+ if (BPF_MODE(insn->code) == BPF_PROBE_MEM) {
+ struct exception_table_entry *ex;
+ u8 *_insn = image + proglen + (start_of_ldx - temp);
+ s64 delta;
+
+ /* populate jmp_offset for JMP above */
+ start_of_ldx[-1] = prog - start_of_ldx;
+
+ if (!bpf_prog->aux->extable)
+ break;
+
+ if (excnt >= bpf_prog->aux->num_exentries) {
+ pr_err("ex gen bug\n");
+ return -EFAULT;
+ }
+ ex = &bpf_prog->aux->extable[excnt++];
+
+ delta = _insn - (u8 *)&ex->insn;
+ if (!is_simm32(delta)) {
+ pr_err("extable->insn doesn't fit into 32-bit\n");
+ return -EFAULT;
+ }
+ /* switch ex to rw buffer for writes */
+ ex = (void *)rw_image + ((void *)ex - (void *)image);
+
+ ex->insn = delta;
+
+ ex->data = EX_TYPE_BPF;
+
+ if (dst_reg > BPF_REG_9) {
+ pr_err("verifier error\n");
+ return -EFAULT;
+ }
+ /*
+ * Compute size of x86 insn and its target dest x86 register.
+ * ex_handler_bpf() will use lower 8 bits to adjust
+ * pt_regs->ip to jump over this x86 instruction
+ * and upper bits to figure out which pt_regs to zero out.
+ * End result: x86 insn "mov rbx, qword ptr [rax+0x14]"
+ * of 4 bytes will be ignored and rbx will be zero inited.
+ */
+ ex->fixup = (prog - start_of_ldx) | (reg2pt_regs[dst_reg] << 8);
+ }
+ break;
+
+ case BPF_STX | BPF_ATOMIC | BPF_W:
+ case BPF_STX | BPF_ATOMIC | BPF_DW:
+ if (insn->imm == (BPF_AND | BPF_FETCH) ||
+ insn->imm == (BPF_OR | BPF_FETCH) ||
+ insn->imm == (BPF_XOR | BPF_FETCH)) {
+ bool is64 = BPF_SIZE(insn->code) == BPF_DW;
+ u32 real_src_reg = src_reg;
+ u32 real_dst_reg = dst_reg;
+ u8 *branch_target;
+
+ /*
+ * Can't be implemented with a single x86 insn.
+ * Need to do a CMPXCHG loop.
+ */
+
+ /* Will need RAX as a CMPXCHG operand so save R0 */
+ emit_mov_reg(&prog, true, BPF_REG_AX, BPF_REG_0);
+ if (src_reg == BPF_REG_0)
+ real_src_reg = BPF_REG_AX;
+ if (dst_reg == BPF_REG_0)
+ real_dst_reg = BPF_REG_AX;
+
+ branch_target = prog;
+ /* Load old value */
+ emit_ldx(&prog, BPF_SIZE(insn->code),
+ BPF_REG_0, real_dst_reg, insn->off);
+ /*
+ * Perform the (commutative) operation locally,
+ * put the result in the AUX_REG.
+ */
+ emit_mov_reg(&prog, is64, AUX_REG, BPF_REG_0);
+ maybe_emit_mod(&prog, AUX_REG, real_src_reg, is64);
+ EMIT2(simple_alu_opcodes[BPF_OP(insn->imm)],
+ add_2reg(0xC0, AUX_REG, real_src_reg));
+ /* Attempt to swap in new value */
+ err = emit_atomic(&prog, BPF_CMPXCHG,
+ real_dst_reg, AUX_REG,
+ insn->off,
+ BPF_SIZE(insn->code));
+ if (WARN_ON(err))
+ return err;
+ /*
+ * ZF tells us whether we won the race. If it's
+ * cleared we need to try again.
+ */
+ EMIT2(X86_JNE, -(prog - branch_target) - 2);
+ /* Return the pre-modification value */
+ emit_mov_reg(&prog, is64, real_src_reg, BPF_REG_0);
+ /* Restore R0 after clobbering RAX */
+ emit_mov_reg(&prog, true, BPF_REG_0, BPF_REG_AX);
+ break;
+ }
+
+ err = emit_atomic(&prog, insn->imm, dst_reg, src_reg,
+ insn->off, BPF_SIZE(insn->code));
+ if (err)
+ return err;
+ break;
+
+ /* call */
+ case BPF_JMP | BPF_CALL:
+ func = (u8 *) __bpf_call_base + imm32;
+ if (tail_call_reachable) {
+ RESTORE_TAIL_CALL_CNT(bpf_prog->aux->stack_depth);
+ if (!imm32 || emit_call(&prog, func, image + addrs[i - 1] + 7))
+ return -EINVAL;
+ } else {
+ if (!imm32 || emit_call(&prog, func, image + addrs[i - 1]))
+ return -EINVAL;
+ }
+ break;
+
+ case BPF_JMP | BPF_TAIL_CALL:
+ if (imm32)
+ emit_bpf_tail_call_direct(&bpf_prog->aux->poke_tab[imm32 - 1],
+ &prog, image + addrs[i - 1],
+ callee_regs_used,
+ bpf_prog->aux->stack_depth,
+ ctx);
+ else
+ emit_bpf_tail_call_indirect(&prog,
+ callee_regs_used,
+ bpf_prog->aux->stack_depth,
+ image + addrs[i - 1],
+ ctx);
+ 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:
+ case BPF_JMP32 | BPF_JEQ | BPF_X:
+ case BPF_JMP32 | BPF_JNE | BPF_X:
+ case BPF_JMP32 | BPF_JGT | BPF_X:
+ case BPF_JMP32 | BPF_JLT | BPF_X:
+ case BPF_JMP32 | BPF_JGE | BPF_X:
+ case BPF_JMP32 | BPF_JLE | BPF_X:
+ case BPF_JMP32 | BPF_JSGT | BPF_X:
+ case BPF_JMP32 | BPF_JSLT | BPF_X:
+ case BPF_JMP32 | BPF_JSGE | BPF_X:
+ case BPF_JMP32 | BPF_JSLE | BPF_X:
+ /* cmp dst_reg, src_reg */
+ maybe_emit_mod(&prog, dst_reg, src_reg,
+ BPF_CLASS(insn->code) == BPF_JMP);
+ EMIT2(0x39, add_2reg(0xC0, dst_reg, src_reg));
+ goto emit_cond_jmp;
+
+ case BPF_JMP | BPF_JSET | BPF_X:
+ case BPF_JMP32 | BPF_JSET | BPF_X:
+ /* test dst_reg, src_reg */
+ maybe_emit_mod(&prog, dst_reg, src_reg,
+ BPF_CLASS(insn->code) == BPF_JMP);
+ EMIT2(0x85, add_2reg(0xC0, dst_reg, src_reg));
+ goto emit_cond_jmp;
+
+ case BPF_JMP | BPF_JSET | BPF_K:
+ case BPF_JMP32 | BPF_JSET | BPF_K:
+ /* test dst_reg, imm32 */
+ maybe_emit_1mod(&prog, dst_reg,
+ BPF_CLASS(insn->code) == BPF_JMP);
+ 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:
+ case BPF_JMP32 | BPF_JEQ | BPF_K:
+ case BPF_JMP32 | BPF_JNE | BPF_K:
+ case BPF_JMP32 | BPF_JGT | BPF_K:
+ case BPF_JMP32 | BPF_JLT | BPF_K:
+ case BPF_JMP32 | BPF_JGE | BPF_K:
+ case BPF_JMP32 | BPF_JLE | BPF_K:
+ case BPF_JMP32 | BPF_JSGT | BPF_K:
+ case BPF_JMP32 | BPF_JSLT | BPF_K:
+ case BPF_JMP32 | BPF_JSGE | BPF_K:
+ case BPF_JMP32 | BPF_JSLE | BPF_K:
+ /* test dst_reg, dst_reg to save one extra byte */
+ if (imm32 == 0) {
+ maybe_emit_mod(&prog, dst_reg, dst_reg,
+ BPF_CLASS(insn->code) == BPF_JMP);
+ EMIT2(0x85, add_2reg(0xC0, dst_reg, dst_reg));
+ goto emit_cond_jmp;
+ }
+
+ /* cmp dst_reg, imm8/32 */
+ maybe_emit_1mod(&prog, dst_reg,
+ BPF_CLASS(insn->code) == BPF_JMP);
+
+ 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)) {
+ if (jmp_padding) {
+ /* To keep the jmp_offset valid, the extra bytes are
+ * padded before the jump insn, so we subtract the
+ * 2 bytes of jmp_cond insn from INSN_SZ_DIFF.
+ *
+ * If the previous pass already emits an imm8
+ * jmp_cond, then this BPF insn won't shrink, so
+ * "nops" is 0.
+ *
+ * On the other hand, if the previous pass emits an
+ * imm32 jmp_cond, the extra 4 bytes(*) is padded to
+ * keep the image from shrinking further.
+ *
+ * (*) imm32 jmp_cond is 6 bytes, and imm8 jmp_cond
+ * is 2 bytes, so the size difference is 4 bytes.
+ */
+ nops = INSN_SZ_DIFF - 2;
+ if (nops != 0 && nops != 4) {
+ pr_err("unexpected jmp_cond padding: %d bytes\n",
+ nops);
+ return -EFAULT;
+ }
+ emit_nops(&prog, nops);
+ }
+ 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:
+ case BPF_JMP32 | BPF_JA:
+ if (BPF_CLASS(insn->code) == BPF_JMP) {
+ 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];
+ } else {
+ if (insn->imm == -1)
+ jmp_offset = -2;
+ else
+ jmp_offset = addrs[i + insn->imm] - addrs[i];
+ }
+
+ if (!jmp_offset) {
+ /*
+ * If jmp_padding is enabled, the extra nops will
+ * be inserted. Otherwise, optimize out nop jumps.
+ */
+ if (jmp_padding) {
+ /* There are 3 possible conditions.
+ * (1) This BPF_JA is already optimized out in
+ * the previous run, so there is no need
+ * to pad any extra byte (0 byte).
+ * (2) The previous pass emits an imm8 jmp,
+ * so we pad 2 bytes to match the previous
+ * insn size.
+ * (3) Similarly, the previous pass emits an
+ * imm32 jmp, and 5 bytes is padded.
+ */
+ nops = INSN_SZ_DIFF;
+ if (nops != 0 && nops != 2 && nops != 5) {
+ pr_err("unexpected nop jump padding: %d bytes\n",
+ nops);
+ return -EFAULT;
+ }
+ emit_nops(&prog, nops);
+ }
+ break;
+ }
+emit_jmp:
+ if (is_imm8(jmp_offset)) {
+ if (jmp_padding) {
+ /* To avoid breaking jmp_offset, the extra bytes
+ * are padded before the actual jmp insn, so
+ * 2 bytes is subtracted from INSN_SZ_DIFF.
+ *
+ * If the previous pass already emits an imm8
+ * jmp, there is nothing to pad (0 byte).
+ *
+ * If it emits an imm32 jmp (5 bytes) previously
+ * and now an imm8 jmp (2 bytes), then we pad
+ * (5 - 2 = 3) bytes to stop the image from
+ * shrinking further.
+ */
+ nops = INSN_SZ_DIFF - 2;
+ if (nops != 0 && nops != 3) {
+ pr_err("unexpected jump padding: %d bytes\n",
+ nops);
+ return -EFAULT;
+ }
+ emit_nops(&prog, INSN_SZ_DIFF - 2);
+ }
+ 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;
+ pop_callee_regs(&prog, callee_regs_used);
+ EMIT1(0xC9); /* leave */
+ emit_return(&prog, image + addrs[i - 1] + (prog - temp));
+ 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(rw_image + proglen, temp, ilen);
+ }
+ proglen += ilen;
+ addrs[i] = proglen;
+ prog = temp;
+ }
+
+ if (image && excnt != bpf_prog->aux->num_exentries) {
+ pr_err("extable is not populated\n");
+ return -EFAULT;
+ }
+ return proglen;
+}
+
+static void save_regs(const struct btf_func_model *m, u8 **prog, int nr_regs,
+ int stack_size)
+{
+ int i;
+
+ /* Store function arguments to stack.
+ * For a function that accepts two pointers the sequence will be:
+ * mov QWORD PTR [rbp-0x10],rdi
+ * mov QWORD PTR [rbp-0x8],rsi
+ */
+ for (i = 0; i < min(nr_regs, 6); i++)
+ emit_stx(prog, BPF_DW, BPF_REG_FP,
+ i == 5 ? X86_REG_R9 : BPF_REG_1 + i,
+ -(stack_size - i * 8));
+}
+
+static void restore_regs(const struct btf_func_model *m, u8 **prog, int nr_regs,
+ int stack_size)
+{
+ int i;
+
+ /* Restore function arguments from stack.
+ * For a function that accepts two pointers the sequence will be:
+ * EMIT4(0x48, 0x8B, 0x7D, 0xF0); mov rdi,QWORD PTR [rbp-0x10]
+ * EMIT4(0x48, 0x8B, 0x75, 0xF8); mov rsi,QWORD PTR [rbp-0x8]
+ */
+ for (i = 0; i < min(nr_regs, 6); i++)
+ emit_ldx(prog, BPF_DW,
+ i == 5 ? X86_REG_R9 : BPF_REG_1 + i,
+ BPF_REG_FP,
+ -(stack_size - i * 8));
+}
+
+static int invoke_bpf_prog(const struct btf_func_model *m, u8 **pprog,
+ struct bpf_tramp_link *l, int stack_size,
+ int run_ctx_off, bool save_ret)
+{
+ u8 *prog = *pprog;
+ u8 *jmp_insn;
+ int ctx_cookie_off = offsetof(struct bpf_tramp_run_ctx, bpf_cookie);
+ struct bpf_prog *p = l->link.prog;
+ u64 cookie = l->cookie;
+
+ /* mov rdi, cookie */
+ emit_mov_imm64(&prog, BPF_REG_1, (long) cookie >> 32, (u32) (long) cookie);
+
+ /* Prepare struct bpf_tramp_run_ctx.
+ *
+ * bpf_tramp_run_ctx is already preserved by
+ * arch_prepare_bpf_trampoline().
+ *
+ * mov QWORD PTR [rbp - run_ctx_off + ctx_cookie_off], rdi
+ */
+ emit_stx(&prog, BPF_DW, BPF_REG_FP, BPF_REG_1, -run_ctx_off + ctx_cookie_off);
+
+ /* arg1: mov rdi, progs[i] */
+ emit_mov_imm64(&prog, BPF_REG_1, (long) p >> 32, (u32) (long) p);
+ /* arg2: lea rsi, [rbp - ctx_cookie_off] */
+ EMIT4(0x48, 0x8D, 0x75, -run_ctx_off);
+
+ if (emit_call(&prog, bpf_trampoline_enter(p), prog))
+ return -EINVAL;
+ /* remember prog start time returned by __bpf_prog_enter */
+ emit_mov_reg(&prog, true, BPF_REG_6, BPF_REG_0);
+
+ /* if (__bpf_prog_enter*(prog) == 0)
+ * goto skip_exec_of_prog;
+ */
+ EMIT3(0x48, 0x85, 0xC0); /* test rax,rax */
+ /* emit 2 nops that will be replaced with JE insn */
+ jmp_insn = prog;
+ emit_nops(&prog, 2);
+
+ /* arg1: lea rdi, [rbp - stack_size] */
+ EMIT4(0x48, 0x8D, 0x7D, -stack_size);
+ /* arg2: progs[i]->insnsi for interpreter */
+ if (!p->jited)
+ emit_mov_imm64(&prog, BPF_REG_2,
+ (long) p->insnsi >> 32,
+ (u32) (long) p->insnsi);
+ /* call JITed bpf program or interpreter */
+ if (emit_call(&prog, p->bpf_func, prog))
+ return -EINVAL;
+
+ /*
+ * BPF_TRAMP_MODIFY_RETURN trampolines can modify the return
+ * of the previous call which is then passed on the stack to
+ * the next BPF program.
+ *
+ * BPF_TRAMP_FENTRY trampoline may need to return the return
+ * value of BPF_PROG_TYPE_STRUCT_OPS prog.
+ */
+ if (save_ret)
+ emit_stx(&prog, BPF_DW, BPF_REG_FP, BPF_REG_0, -8);
+
+ /* replace 2 nops with JE insn, since jmp target is known */
+ jmp_insn[0] = X86_JE;
+ jmp_insn[1] = prog - jmp_insn - 2;
+
+ /* arg1: mov rdi, progs[i] */
+ emit_mov_imm64(&prog, BPF_REG_1, (long) p >> 32, (u32) (long) p);
+ /* arg2: mov rsi, rbx <- start time in nsec */
+ emit_mov_reg(&prog, true, BPF_REG_2, BPF_REG_6);
+ /* arg3: lea rdx, [rbp - run_ctx_off] */
+ EMIT4(0x48, 0x8D, 0x55, -run_ctx_off);
+ if (emit_call(&prog, bpf_trampoline_exit(p), prog))
+ return -EINVAL;
+
+ *pprog = prog;
+ return 0;
+}
+
+static void emit_align(u8 **pprog, u32 align)
+{
+ u8 *target, *prog = *pprog;
+
+ target = PTR_ALIGN(prog, align);
+ if (target != prog)
+ emit_nops(&prog, target - prog);
+
+ *pprog = prog;
+}
+
+static int emit_cond_near_jump(u8 **pprog, void *func, void *ip, u8 jmp_cond)
+{
+ u8 *prog = *pprog;
+ s64 offset;
+
+ offset = func - (ip + 2 + 4);
+ if (!is_simm32(offset)) {
+ pr_err("Target %p is out of range\n", func);
+ return -EINVAL;
+ }
+ EMIT2_off32(0x0F, jmp_cond + 0x10, offset);
+ *pprog = prog;
+ return 0;
+}
+
+static int invoke_bpf(const struct btf_func_model *m, u8 **pprog,
+ struct bpf_tramp_links *tl, int stack_size,
+ int run_ctx_off, bool save_ret)
+{
+ int i;
+ u8 *prog = *pprog;
+
+ for (i = 0; i < tl->nr_links; i++) {
+ if (invoke_bpf_prog(m, &prog, tl->links[i], stack_size,
+ run_ctx_off, save_ret))
+ return -EINVAL;
+ }
+ *pprog = prog;
+ return 0;
+}
+
+static int invoke_bpf_mod_ret(const struct btf_func_model *m, u8 **pprog,
+ struct bpf_tramp_links *tl, int stack_size,
+ int run_ctx_off, u8 **branches)
+{
+ u8 *prog = *pprog;
+ int i;
+
+ /* The first fmod_ret program will receive a garbage return value.
+ * Set this to 0 to avoid confusing the program.
+ */
+ emit_mov_imm32(&prog, false, BPF_REG_0, 0);
+ emit_stx(&prog, BPF_DW, BPF_REG_FP, BPF_REG_0, -8);
+ for (i = 0; i < tl->nr_links; i++) {
+ if (invoke_bpf_prog(m, &prog, tl->links[i], stack_size, run_ctx_off, true))
+ return -EINVAL;
+
+ /* mod_ret prog stored return value into [rbp - 8]. Emit:
+ * if (*(u64 *)(rbp - 8) != 0)
+ * goto do_fexit;
+ */
+ /* cmp QWORD PTR [rbp - 0x8], 0x0 */
+ EMIT4(0x48, 0x83, 0x7d, 0xf8); EMIT1(0x00);
+
+ /* Save the location of the branch and Generate 6 nops
+ * (4 bytes for an offset and 2 bytes for the jump) These nops
+ * are replaced with a conditional jump once do_fexit (i.e. the
+ * start of the fexit invocation) is finalized.
+ */
+ branches[i] = prog;
+ emit_nops(&prog, 4 + 2);
+ }
+
+ *pprog = prog;
+ return 0;
+}
+
+/* Example:
+ * __be16 eth_type_trans(struct sk_buff *skb, struct net_device *dev);
+ * its 'struct btf_func_model' will be nr_args=2
+ * The assembly code when eth_type_trans is executing after trampoline:
+ *
+ * push rbp
+ * mov rbp, rsp
+ * sub rsp, 16 // space for skb and dev
+ * push rbx // temp regs to pass start time
+ * mov qword ptr [rbp - 16], rdi // save skb pointer to stack
+ * mov qword ptr [rbp - 8], rsi // save dev pointer to stack
+ * call __bpf_prog_enter // rcu_read_lock and preempt_disable
+ * mov rbx, rax // remember start time in bpf stats are enabled
+ * lea rdi, [rbp - 16] // R1==ctx of bpf prog
+ * call addr_of_jited_FENTRY_prog
+ * movabsq rdi, 64bit_addr_of_struct_bpf_prog // unused if bpf stats are off
+ * mov rsi, rbx // prog start time
+ * call __bpf_prog_exit // rcu_read_unlock, preempt_enable and stats math
+ * mov rdi, qword ptr [rbp - 16] // restore skb pointer from stack
+ * mov rsi, qword ptr [rbp - 8] // restore dev pointer from stack
+ * pop rbx
+ * leave
+ * ret
+ *
+ * eth_type_trans has 5 byte nop at the beginning. These 5 bytes will be
+ * replaced with 'call generated_bpf_trampoline'. When it returns
+ * eth_type_trans will continue executing with original skb and dev pointers.
+ *
+ * The assembly code when eth_type_trans is called from trampoline:
+ *
+ * push rbp
+ * mov rbp, rsp
+ * sub rsp, 24 // space for skb, dev, return value
+ * push rbx // temp regs to pass start time
+ * mov qword ptr [rbp - 24], rdi // save skb pointer to stack
+ * mov qword ptr [rbp - 16], rsi // save dev pointer to stack
+ * call __bpf_prog_enter // rcu_read_lock and preempt_disable
+ * mov rbx, rax // remember start time if bpf stats are enabled
+ * lea rdi, [rbp - 24] // R1==ctx of bpf prog
+ * call addr_of_jited_FENTRY_prog // bpf prog can access skb and dev
+ * movabsq rdi, 64bit_addr_of_struct_bpf_prog // unused if bpf stats are off
+ * mov rsi, rbx // prog start time
+ * call __bpf_prog_exit // rcu_read_unlock, preempt_enable and stats math
+ * mov rdi, qword ptr [rbp - 24] // restore skb pointer from stack
+ * mov rsi, qword ptr [rbp - 16] // restore dev pointer from stack
+ * call eth_type_trans+5 // execute body of eth_type_trans
+ * mov qword ptr [rbp - 8], rax // save return value
+ * call __bpf_prog_enter // rcu_read_lock and preempt_disable
+ * mov rbx, rax // remember start time in bpf stats are enabled
+ * lea rdi, [rbp - 24] // R1==ctx of bpf prog
+ * call addr_of_jited_FEXIT_prog // bpf prog can access skb, dev, return value
+ * movabsq rdi, 64bit_addr_of_struct_bpf_prog // unused if bpf stats are off
+ * mov rsi, rbx // prog start time
+ * call __bpf_prog_exit // rcu_read_unlock, preempt_enable and stats math
+ * mov rax, qword ptr [rbp - 8] // restore eth_type_trans's return value
+ * pop rbx
+ * leave
+ * add rsp, 8 // skip eth_type_trans's frame
+ * ret // return to its caller
+ */
+int arch_prepare_bpf_trampoline(struct bpf_tramp_image *im, void *image, void *image_end,
+ const struct btf_func_model *m, u32 flags,
+ struct bpf_tramp_links *tlinks,
+ void *func_addr)
+{
+ int i, ret, nr_regs = m->nr_args, stack_size = 0;
+ int regs_off, nregs_off, ip_off, run_ctx_off;
+ struct bpf_tramp_links *fentry = &tlinks[BPF_TRAMP_FENTRY];
+ struct bpf_tramp_links *fexit = &tlinks[BPF_TRAMP_FEXIT];
+ struct bpf_tramp_links *fmod_ret = &tlinks[BPF_TRAMP_MODIFY_RETURN];
+ void *orig_call = func_addr;
+ u8 **branches = NULL;
+ u8 *prog;
+ bool save_ret;
+
+ /* extra registers for struct arguments */
+ for (i = 0; i < m->nr_args; i++)
+ if (m->arg_flags[i] & BTF_FMODEL_STRUCT_ARG)
+ nr_regs += (m->arg_size[i] + 7) / 8 - 1;
+
+ /* x86-64 supports up to 6 arguments. 7+ can be added in the future */
+ if (nr_regs > 6)
+ return -ENOTSUPP;
+
+ /* Generated trampoline stack layout:
+ *
+ * RBP + 8 [ return address ]
+ * RBP + 0 [ RBP ]
+ *
+ * RBP - 8 [ return value ] BPF_TRAMP_F_CALL_ORIG or
+ * BPF_TRAMP_F_RET_FENTRY_RET flags
+ *
+ * [ reg_argN ] always
+ * [ ... ]
+ * RBP - regs_off [ reg_arg1 ] program's ctx pointer
+ *
+ * RBP - nregs_off [ regs count ] always
+ *
+ * RBP - ip_off [ traced function ] BPF_TRAMP_F_IP_ARG flag
+ *
+ * RBP - run_ctx_off [ bpf_tramp_run_ctx ]
+ * RSP [ tail_call_cnt ] BPF_TRAMP_F_TAIL_CALL_CTX
+ */
+
+ /* room for return value of orig_call or fentry prog */
+ save_ret = flags & (BPF_TRAMP_F_CALL_ORIG | BPF_TRAMP_F_RET_FENTRY_RET);
+ if (save_ret)
+ stack_size += 8;
+
+ stack_size += nr_regs * 8;
+ regs_off = stack_size;
+
+ /* regs count */
+ stack_size += 8;
+ nregs_off = stack_size;
+
+ if (flags & BPF_TRAMP_F_IP_ARG)
+ stack_size += 8; /* room for IP address argument */
+
+ ip_off = stack_size;
+
+ stack_size += (sizeof(struct bpf_tramp_run_ctx) + 7) & ~0x7;
+ run_ctx_off = stack_size;
+
+ if (flags & BPF_TRAMP_F_SKIP_FRAME) {
+ /* skip patched call instruction and point orig_call to actual
+ * body of the kernel function.
+ */
+ if (is_endbr(*(u32 *)orig_call))
+ orig_call += ENDBR_INSN_SIZE;
+ orig_call += X86_PATCH_SIZE;
+ }
+
+ prog = image;
+
+ EMIT_ENDBR();
+ EMIT1(0x55); /* push rbp */
+ EMIT3(0x48, 0x89, 0xE5); /* mov rbp, rsp */
+ EMIT4(0x48, 0x83, 0xEC, stack_size); /* sub rsp, stack_size */
+ if (flags & BPF_TRAMP_F_TAIL_CALL_CTX)
+ EMIT1(0x50); /* push rax */
+ EMIT1(0x53); /* push rbx */
+
+ /* Store number of argument registers of the traced function:
+ * mov rax, nr_regs
+ * mov QWORD PTR [rbp - nregs_off], rax
+ */
+ emit_mov_imm64(&prog, BPF_REG_0, 0, (u32) nr_regs);
+ emit_stx(&prog, BPF_DW, BPF_REG_FP, BPF_REG_0, -nregs_off);
+
+ if (flags & BPF_TRAMP_F_IP_ARG) {
+ /* Store IP address of the traced function:
+ * movabsq rax, func_addr
+ * mov QWORD PTR [rbp - ip_off], rax
+ */
+ emit_mov_imm64(&prog, BPF_REG_0, (long) func_addr >> 32, (u32) (long) func_addr);
+ emit_stx(&prog, BPF_DW, BPF_REG_FP, BPF_REG_0, -ip_off);
+ }
+
+ save_regs(m, &prog, nr_regs, regs_off);
+
+ if (flags & BPF_TRAMP_F_CALL_ORIG) {
+ /* arg1: mov rdi, im */
+ emit_mov_imm64(&prog, BPF_REG_1, (long) im >> 32, (u32) (long) im);
+ if (emit_call(&prog, __bpf_tramp_enter, prog)) {
+ ret = -EINVAL;
+ goto cleanup;
+ }
+ }
+
+ if (fentry->nr_links)
+ if (invoke_bpf(m, &prog, fentry, regs_off, run_ctx_off,
+ flags & BPF_TRAMP_F_RET_FENTRY_RET))
+ return -EINVAL;
+
+ if (fmod_ret->nr_links) {
+ branches = kcalloc(fmod_ret->nr_links, sizeof(u8 *),
+ GFP_KERNEL);
+ if (!branches)
+ return -ENOMEM;
+
+ if (invoke_bpf_mod_ret(m, &prog, fmod_ret, regs_off,
+ run_ctx_off, branches)) {
+ ret = -EINVAL;
+ goto cleanup;
+ }
+ }
+
+ if (flags & BPF_TRAMP_F_CALL_ORIG) {
+ restore_regs(m, &prog, nr_regs, regs_off);
+
+ if (flags & BPF_TRAMP_F_TAIL_CALL_CTX)
+ /* Before calling the original function, restore the
+ * tail_call_cnt from stack to rax.
+ */
+ RESTORE_TAIL_CALL_CNT(stack_size);
+
+ if (flags & BPF_TRAMP_F_ORIG_STACK) {
+ emit_ldx(&prog, BPF_DW, BPF_REG_6, BPF_REG_FP, 8);
+ EMIT2(0xff, 0xd3); /* call *rbx */
+ } else {
+ /* call original function */
+ if (emit_call(&prog, orig_call, prog)) {
+ ret = -EINVAL;
+ goto cleanup;
+ }
+ }
+ /* remember return value in a stack for bpf prog to access */
+ emit_stx(&prog, BPF_DW, BPF_REG_FP, BPF_REG_0, -8);
+ im->ip_after_call = prog;
+ memcpy(prog, x86_nops[5], X86_PATCH_SIZE);
+ prog += X86_PATCH_SIZE;
+ }
+
+ if (fmod_ret->nr_links) {
+ /* From Intel 64 and IA-32 Architectures Optimization
+ * Reference Manual, 3.4.1.4 Code Alignment, Assembly/Compiler
+ * Coding Rule 11: All branch targets should be 16-byte
+ * aligned.
+ */
+ emit_align(&prog, 16);
+ /* Update the branches saved in invoke_bpf_mod_ret with the
+ * aligned address of do_fexit.
+ */
+ for (i = 0; i < fmod_ret->nr_links; i++)
+ emit_cond_near_jump(&branches[i], prog, branches[i],
+ X86_JNE);
+ }
+
+ if (fexit->nr_links)
+ if (invoke_bpf(m, &prog, fexit, regs_off, run_ctx_off, false)) {
+ ret = -EINVAL;
+ goto cleanup;
+ }
+
+ if (flags & BPF_TRAMP_F_RESTORE_REGS)
+ restore_regs(m, &prog, nr_regs, regs_off);
+
+ /* This needs to be done regardless. If there were fmod_ret programs,
+ * the return value is only updated on the stack and still needs to be
+ * restored to R0.
+ */
+ if (flags & BPF_TRAMP_F_CALL_ORIG) {
+ im->ip_epilogue = prog;
+ /* arg1: mov rdi, im */
+ emit_mov_imm64(&prog, BPF_REG_1, (long) im >> 32, (u32) (long) im);
+ if (emit_call(&prog, __bpf_tramp_exit, prog)) {
+ ret = -EINVAL;
+ goto cleanup;
+ }
+ } else if (flags & BPF_TRAMP_F_TAIL_CALL_CTX)
+ /* Before running the original function, restore the
+ * tail_call_cnt from stack to rax.
+ */
+ RESTORE_TAIL_CALL_CNT(stack_size);
+
+ /* restore return value of orig_call or fentry prog back into RAX */
+ if (save_ret)
+ emit_ldx(&prog, BPF_DW, BPF_REG_0, BPF_REG_FP, -8);
+
+ EMIT1(0x5B); /* pop rbx */
+ EMIT1(0xC9); /* leave */
+ if (flags & BPF_TRAMP_F_SKIP_FRAME)
+ /* skip our return address and return to parent */
+ EMIT4(0x48, 0x83, 0xC4, 8); /* add rsp, 8 */
+ emit_return(&prog, prog);
+ /* Make sure the trampoline generation logic doesn't overflow */
+ if (WARN_ON_ONCE(prog > (u8 *)image_end - BPF_INSN_SAFETY)) {
+ ret = -EFAULT;
+ goto cleanup;
+ }
+ ret = prog - (u8 *)image;
+
+cleanup:
+ kfree(branches);
+ return ret;
+}
+
+static int emit_bpf_dispatcher(u8 **pprog, int a, int b, s64 *progs, u8 *image, u8 *buf)
+{
+ u8 *jg_reloc, *prog = *pprog;
+ int pivot, err, jg_bytes = 1;
+ s64 jg_offset;
+
+ if (a == b) {
+ /* Leaf node of recursion, i.e. not a range of indices
+ * anymore.
+ */
+ EMIT1(add_1mod(0x48, BPF_REG_3)); /* cmp rdx,func */
+ if (!is_simm32(progs[a]))
+ return -1;
+ EMIT2_off32(0x81, add_1reg(0xF8, BPF_REG_3),
+ progs[a]);
+ err = emit_cond_near_jump(&prog, /* je func */
+ (void *)progs[a], image + (prog - buf),
+ X86_JE);
+ if (err)
+ return err;
+
+ emit_indirect_jump(&prog, 2 /* rdx */, image + (prog - buf));
+
+ *pprog = prog;
+ return 0;
+ }
+
+ /* Not a leaf node, so we pivot, and recursively descend into
+ * the lower and upper ranges.
+ */
+ pivot = (b - a) / 2;
+ EMIT1(add_1mod(0x48, BPF_REG_3)); /* cmp rdx,func */
+ if (!is_simm32(progs[a + pivot]))
+ return -1;
+ EMIT2_off32(0x81, add_1reg(0xF8, BPF_REG_3), progs[a + pivot]);
+
+ if (pivot > 2) { /* jg upper_part */
+ /* Require near jump. */
+ jg_bytes = 4;
+ EMIT2_off32(0x0F, X86_JG + 0x10, 0);
+ } else {
+ EMIT2(X86_JG, 0);
+ }
+ jg_reloc = prog;
+
+ err = emit_bpf_dispatcher(&prog, a, a + pivot, /* emit lower_part */
+ progs, image, buf);
+ if (err)
+ return err;
+
+ /* From Intel 64 and IA-32 Architectures Optimization
+ * Reference Manual, 3.4.1.4 Code Alignment, Assembly/Compiler
+ * Coding Rule 11: All branch targets should be 16-byte
+ * aligned.
+ */
+ emit_align(&prog, 16);
+ jg_offset = prog - jg_reloc;
+ emit_code(jg_reloc - jg_bytes, jg_offset, jg_bytes);
+
+ err = emit_bpf_dispatcher(&prog, a + pivot + 1, /* emit upper_part */
+ b, progs, image, buf);
+ if (err)
+ return err;
+
+ *pprog = prog;
+ return 0;
+}
+
+static int cmp_ips(const void *a, const void *b)
+{
+ const s64 *ipa = a;
+ const s64 *ipb = b;
+
+ if (*ipa > *ipb)
+ return 1;
+ if (*ipa < *ipb)
+ return -1;
+ return 0;
+}
+
+int arch_prepare_bpf_dispatcher(void *image, void *buf, s64 *funcs, int num_funcs)
+{
+ u8 *prog = buf;
+
+ sort(funcs, num_funcs, sizeof(funcs[0]), cmp_ips, NULL);
+ return emit_bpf_dispatcher(&prog, 0, num_funcs - 1, funcs, image, buf);
+}
+
+struct x64_jit_data {
+ struct bpf_binary_header *rw_header;
+ struct bpf_binary_header *header;
+ int *addrs;
+ u8 *image;
+ int proglen;
+ struct jit_context ctx;
+};
+
+#define MAX_PASSES 20
+#define PADDING_PASSES (MAX_PASSES - 5)
+
+struct bpf_prog *bpf_int_jit_compile(struct bpf_prog *prog)
+{
+ struct bpf_binary_header *rw_header = NULL;
+ 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;
+ bool padding = false;
+ u8 *rw_image = NULL;
+ 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;
+ rw_header = jit_data->rw_header;
+ rw_image = (void *)rw_header + ((void *)image - (void *)header);
+ extra_pass = true;
+ padding = true;
+ goto skip_init_addrs;
+ }
+ addrs = kvmalloc_array(prog->len + 1, 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 < MAX_PASSES || image; pass++) {
+ if (!padding && pass >= PADDING_PASSES)
+ padding = true;
+ proglen = do_jit(prog, addrs, image, rw_image, oldproglen, &ctx, padding);
+ if (proglen <= 0) {
+out_image:
+ image = NULL;
+ if (header) {
+ bpf_arch_text_copy(&header->size, &rw_header->size,
+ sizeof(rw_header->size));
+ bpf_jit_binary_pack_free(header, rw_header);
+ }
+ /* Fall back to interpreter mode */
+ prog = orig_prog;
+ if (extra_pass) {
+ prog->bpf_func = NULL;
+ prog->jited = 0;
+ prog->jited_len = 0;
+ }
+ 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) {
+ /*
+ * The number of entries in extable is the number of BPF_LDX
+ * insns that access kernel memory via "pointer to BTF type".
+ * The verifier changed their opcode from LDX|MEM|size
+ * to LDX|PROBE_MEM|size to make JITing easier.
+ */
+ u32 align = __alignof__(struct exception_table_entry);
+ u32 extable_size = prog->aux->num_exentries *
+ sizeof(struct exception_table_entry);
+
+ /* allocate module memory for x86 insns and extable */
+ header = bpf_jit_binary_pack_alloc(roundup(proglen, align) + extable_size,
+ &image, align, &rw_header, &rw_image,
+ jit_fill_hole);
+ if (!header) {
+ prog = orig_prog;
+ goto out_addrs;
+ }
+ prog->aux->extable = (void *) image + roundup(proglen, align);
+ }
+ oldproglen = proglen;
+ cond_resched();
+ }
+
+ if (bpf_jit_enable > 1)
+ bpf_jit_dump(prog->len, proglen, pass + 1, rw_image);
+
+ if (image) {
+ if (!prog->is_func || extra_pass) {
+ /*
+ * bpf_jit_binary_pack_finalize fails in two scenarios:
+ * 1) header is not pointing to proper module memory;
+ * 2) the arch doesn't support bpf_arch_text_copy().
+ *
+ * Both cases are serious bugs and justify WARN_ON.
+ */
+ if (WARN_ON(bpf_jit_binary_pack_finalize(prog, header, rw_header))) {
+ /* header has been freed */
+ header = NULL;
+ goto out_image;
+ }
+
+ bpf_tail_call_direct_fixup(prog);
+ } else {
+ jit_data->addrs = addrs;
+ jit_data->ctx = ctx;
+ jit_data->proglen = proglen;
+ jit_data->image = image;
+ jit_data->header = header;
+ jit_data->rw_header = rw_header;
+ }
+ prog->bpf_func = (void *)image;
+ prog->jited = 1;
+ prog->jited_len = proglen;
+ } else {
+ prog = orig_prog;
+ }
+
+ if (!image || !prog->is_func || extra_pass) {
+ if (image)
+ bpf_prog_fill_jited_linfo(prog, addrs + 1);
+out_addrs:
+ kvfree(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;
+}
+
+bool bpf_jit_supports_kfunc_call(void)
+{
+ return true;
+}
+
+void *bpf_arch_text_copy(void *dst, void *src, size_t len)
+{
+ if (text_poke_copy(dst, src, len) == NULL)
+ return ERR_PTR(-EINVAL);
+ return dst;
+}
+
+/* Indicate the JIT backend supports mixing bpf2bpf and tailcalls. */
+bool bpf_jit_supports_subprog_tailcalls(void)
+{
+ return true;
+}
+
+void bpf_jit_free(struct bpf_prog *prog)
+{
+ if (prog->jited) {
+ struct x64_jit_data *jit_data = prog->aux->jit_data;
+ struct bpf_binary_header *hdr;
+
+ /*
+ * If we fail the final pass of JIT (from jit_subprogs),
+ * the program may not be finalized yet. Call finalize here
+ * before freeing it.
+ */
+ if (jit_data) {
+ bpf_jit_binary_pack_finalize(prog, jit_data->header,
+ jit_data->rw_header);
+ kvfree(jit_data->addrs);
+ kfree(jit_data);
+ }
+ hdr = bpf_jit_binary_pack_hdr(prog);
+ bpf_jit_binary_pack_free(hdr, NULL);
+ WARN_ON_ONCE(!bpf_prog_kallsyms_verify_off(prog));
+ }
+
+ bpf_prog_unlock_free(prog);
+}
+
+void bpf_arch_poke_desc_update(struct bpf_jit_poke_descriptor *poke,
+ struct bpf_prog *new, struct bpf_prog *old)
+{
+ u8 *old_addr, *new_addr, *old_bypass_addr;
+ int ret;
+
+ old_bypass_addr = old ? NULL : poke->bypass_addr;
+ old_addr = old ? (u8 *)old->bpf_func + poke->adj_off : NULL;
+ new_addr = new ? (u8 *)new->bpf_func + poke->adj_off : NULL;
+
+ /*
+ * On program loading or teardown, the program's kallsym entry
+ * might not be in place, so we use __bpf_arch_text_poke to skip
+ * the kallsyms check.
+ */
+ if (new) {
+ ret = __bpf_arch_text_poke(poke->tailcall_target,
+ BPF_MOD_JUMP,
+ old_addr, new_addr);
+ BUG_ON(ret < 0);
+ if (!old) {
+ ret = __bpf_arch_text_poke(poke->tailcall_bypass,
+ BPF_MOD_JUMP,
+ poke->bypass_addr,
+ NULL);
+ BUG_ON(ret < 0);
+ }
+ } else {
+ ret = __bpf_arch_text_poke(poke->tailcall_bypass,
+ BPF_MOD_JUMP,
+ old_bypass_addr,
+ poke->bypass_addr);
+ BUG_ON(ret < 0);
+ /* let other CPUs finish the execution of program
+ * so that it will not possible to expose them
+ * to invalid nop, stack unwind, nop state
+ */
+ if (!ret)
+ synchronize_rcu();
+ ret = __bpf_arch_text_poke(poke->tailcall_target,
+ BPF_MOD_JUMP,
+ old_addr, NULL);
+ BUG_ON(ret < 0);
+ }
+}