Adding upstream version 6.1.76.upstream/6.1.76upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 2228 insertions, 0 deletions

diff --git a/arch/arm64/net/bpf_jit_comp.c b/arch/arm64/net/bpf_jit_comp.c
new file mode 100644
index 000000000..0ce5f13ea
--- /dev/null
+++ b/arch/arm64/net/bpf_jit_comp.c
@@ -0,0 +1,2228 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * BPF JIT compiler for ARM64
+ *
+ * Copyright (C) 2014-2016 Zi Shen Lim <zlim.lnx@gmail.com>
+ */
+
+#define pr_fmt(fmt) "bpf_jit: " fmt
+
+#include <linux/bitfield.h>
+#include <linux/bpf.h>
+#include <linux/filter.h>
+#include <linux/memory.h>
+#include <linux/printk.h>
+#include <linux/slab.h>
+
+#include <asm/asm-extable.h>
+#include <asm/byteorder.h>
+#include <asm/cacheflush.h>
+#include <asm/debug-monitors.h>
+#include <asm/insn.h>
+#include <asm/patching.h>
+#include <asm/set_memory.h>
+
+#include "bpf_jit.h"
+
+#define TMP_REG_1 (MAX_BPF_JIT_REG + 0)
+#define TMP_REG_2 (MAX_BPF_JIT_REG + 1)
+#define TCALL_CNT (MAX_BPF_JIT_REG + 2)
+#define TMP_REG_3 (MAX_BPF_JIT_REG + 3)
+#define FP_BOTTOM (MAX_BPF_JIT_REG + 4)
+
+#define check_imm(bits, imm) do {				\
+	if ((((imm) > 0) && ((imm) >> (bits))) ||		\
+	    (((imm) < 0) && (~(imm) >> (bits)))) {		\
+		pr_info("[%2d] imm=%d(0x%x) out of range\n",	\
+			i, imm, imm);				\
+		return -EINVAL;					\
+	}							\
+} while (0)
+#define check_imm19(imm) check_imm(19, imm)
+#define check_imm26(imm) check_imm(26, imm)
+
+/* Map BPF registers to A64 registers */
+static const int bpf2a64[] = {
+	/* return value from in-kernel function, and exit value from eBPF */
+	[BPF_REG_0] = A64_R(7),
+	/* arguments from eBPF program to in-kernel function */
+	[BPF_REG_1] = A64_R(0),
+	[BPF_REG_2] = A64_R(1),
+	[BPF_REG_3] = A64_R(2),
+	[BPF_REG_4] = A64_R(3),
+	[BPF_REG_5] = A64_R(4),
+	/* callee saved registers that in-kernel function will preserve */
+	[BPF_REG_6] = A64_R(19),
+	[BPF_REG_7] = A64_R(20),
+	[BPF_REG_8] = A64_R(21),
+	[BPF_REG_9] = A64_R(22),
+	/* read-only frame pointer to access stack */
+	[BPF_REG_FP] = A64_R(25),
+	/* temporary registers for BPF JIT */
+	[TMP_REG_1] = A64_R(10),
+	[TMP_REG_2] = A64_R(11),
+	[TMP_REG_3] = A64_R(12),
+	/* tail_call_cnt */
+	[TCALL_CNT] = A64_R(26),
+	/* temporary register for blinding constants */
+	[BPF_REG_AX] = A64_R(9),
+	[FP_BOTTOM] = A64_R(27),
+};
+
+struct jit_ctx {
+	const struct bpf_prog *prog;
+	int idx;
+	int epilogue_offset;
+	int *offset;
+	int exentry_idx;
+	__le32 *image;
+	u32 stack_size;
+	int fpb_offset;
+};
+
+struct bpf_plt {
+	u32 insn_ldr; /* load target */
+	u32 insn_br;  /* branch to target */
+	u64 target;   /* target value */
+};
+
+#define PLT_TARGET_SIZE   sizeof_field(struct bpf_plt, target)
+#define PLT_TARGET_OFFSET offsetof(struct bpf_plt, target)
+
+static inline void emit(const u32 insn, struct jit_ctx *ctx)
+{
+	if (ctx->image != NULL)
+		ctx->image[ctx->idx] = cpu_to_le32(insn);
+
+	ctx->idx++;
+}
+
+static inline void emit_a64_mov_i(const int is64, const int reg,
+				  const s32 val, struct jit_ctx *ctx)
+{
+	u16 hi = val >> 16;
+	u16 lo = val & 0xffff;
+
+	if (hi & 0x8000) {
+		if (hi == 0xffff) {
+			emit(A64_MOVN(is64, reg, (u16)~lo, 0), ctx);
+		} else {
+			emit(A64_MOVN(is64, reg, (u16)~hi, 16), ctx);
+			if (lo != 0xffff)
+				emit(A64_MOVK(is64, reg, lo, 0), ctx);
+		}
+	} else {
+		emit(A64_MOVZ(is64, reg, lo, 0), ctx);
+		if (hi)
+			emit(A64_MOVK(is64, reg, hi, 16), ctx);
+	}
+}
+
+static int i64_i16_blocks(const u64 val, bool inverse)
+{
+	return (((val >>  0) & 0xffff) != (inverse ? 0xffff : 0x0000)) +
+	       (((val >> 16) & 0xffff) != (inverse ? 0xffff : 0x0000)) +
+	       (((val >> 32) & 0xffff) != (inverse ? 0xffff : 0x0000)) +
+	       (((val >> 48) & 0xffff) != (inverse ? 0xffff : 0x0000));
+}
+
+static inline void emit_a64_mov_i64(const int reg, const u64 val,
+				    struct jit_ctx *ctx)
+{
+	u64 nrm_tmp = val, rev_tmp = ~val;
+	bool inverse;
+	int shift;
+
+	if (!(nrm_tmp >> 32))
+		return emit_a64_mov_i(0, reg, (u32)val, ctx);
+
+	inverse = i64_i16_blocks(nrm_tmp, true) < i64_i16_blocks(nrm_tmp, false);
+	shift = max(round_down((inverse ? (fls64(rev_tmp) - 1) :
+					  (fls64(nrm_tmp) - 1)), 16), 0);
+	if (inverse)
+		emit(A64_MOVN(1, reg, (rev_tmp >> shift) & 0xffff, shift), ctx);
+	else
+		emit(A64_MOVZ(1, reg, (nrm_tmp >> shift) & 0xffff, shift), ctx);
+	shift -= 16;
+	while (shift >= 0) {
+		if (((nrm_tmp >> shift) & 0xffff) != (inverse ? 0xffff : 0x0000))
+			emit(A64_MOVK(1, reg, (nrm_tmp >> shift) & 0xffff, shift), ctx);
+		shift -= 16;
+	}
+}
+
+static inline void emit_bti(u32 insn, struct jit_ctx *ctx)
+{
+	if (IS_ENABLED(CONFIG_ARM64_BTI_KERNEL))
+		emit(insn, ctx);
+}
+
+/*
+ * Kernel addresses in the vmalloc space use at most 48 bits, and the
+ * remaining bits are guaranteed to be 0x1. So we can compose the address
+ * with a fixed length movn/movk/movk sequence.
+ */
+static inline void emit_addr_mov_i64(const int reg, const u64 val,
+				     struct jit_ctx *ctx)
+{
+	u64 tmp = val;
+	int shift = 0;
+
+	emit(A64_MOVN(1, reg, ~tmp & 0xffff, shift), ctx);
+	while (shift < 32) {
+		tmp >>= 16;
+		shift += 16;
+		emit(A64_MOVK(1, reg, tmp & 0xffff, shift), ctx);
+	}
+}
+
+static inline void emit_call(u64 target, struct jit_ctx *ctx)
+{
+	u8 tmp = bpf2a64[TMP_REG_1];
+
+	emit_addr_mov_i64(tmp, target, ctx);
+	emit(A64_BLR(tmp), ctx);
+}
+
+static inline int bpf2a64_offset(int bpf_insn, int off,
+				 const struct jit_ctx *ctx)
+{
+	/* BPF JMP offset is relative to the next instruction */
+	bpf_insn++;
+	/*
+	 * Whereas arm64 branch instructions encode the offset
+	 * from the branch itself, so we must subtract 1 from the
+	 * instruction offset.
+	 */
+	return ctx->offset[bpf_insn + off] - (ctx->offset[bpf_insn] - 1);
+}
+
+static void jit_fill_hole(void *area, unsigned int size)
+{
+	__le32 *ptr;
+	/* We are guaranteed to have aligned memory. */
+	for (ptr = area; size >= sizeof(u32); size -= sizeof(u32))
+		*ptr++ = cpu_to_le32(AARCH64_BREAK_FAULT);
+}
+
+static inline int epilogue_offset(const struct jit_ctx *ctx)
+{
+	int to = ctx->epilogue_offset;
+	int from = ctx->idx;
+
+	return to - from;
+}
+
+static bool is_addsub_imm(u32 imm)
+{
+	/* Either imm12 or shifted imm12. */
+	return !(imm & ~0xfff) || !(imm & ~0xfff000);
+}
+
+/*
+ * There are 3 types of AArch64 LDR/STR (immediate) instruction:
+ * Post-index, Pre-index, Unsigned offset.
+ *
+ * For BPF ldr/str, the "unsigned offset" type is sufficient.
+ *
+ * "Unsigned offset" type LDR(immediate) format:
+ *
+ *    3                   2                   1                   0
+ *  1 0 9 8 7 6 5 4 3 2 1 0 9 8 7 6 5 4 3 2 1 0 9 8 7 6 5 4 3 2 1 0
+ * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ * |x x|1 1 1 0 0 1 0 1|         imm12         |    Rn   |    Rt   |
+ * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ * scale
+ *
+ * "Unsigned offset" type STR(immediate) format:
+ *    3                   2                   1                   0
+ *  1 0 9 8 7 6 5 4 3 2 1 0 9 8 7 6 5 4 3 2 1 0 9 8 7 6 5 4 3 2 1 0
+ * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ * |x x|1 1 1 0 0 1 0 0|         imm12         |    Rn   |    Rt   |
+ * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ * scale
+ *
+ * The offset is calculated from imm12 and scale in the following way:
+ *
+ * offset = (u64)imm12 << scale
+ */
+static bool is_lsi_offset(int offset, int scale)
+{
+	if (offset < 0)
+		return false;
+
+	if (offset > (0xFFF << scale))
+		return false;
+
+	if (offset & ((1 << scale) - 1))
+		return false;
+
+	return true;
+}
+
+/* generated prologue:
+ *      bti c // if CONFIG_ARM64_BTI_KERNEL
+ *      mov x9, lr
+ *      nop  // POKE_OFFSET
+ *      paciasp // if CONFIG_ARM64_PTR_AUTH_KERNEL
+ *      stp x29, lr, [sp, #-16]!
+ *      mov x29, sp
+ *      stp x19, x20, [sp, #-16]!
+ *      stp x21, x22, [sp, #-16]!
+ *      stp x25, x26, [sp, #-16]!
+ *      stp x27, x28, [sp, #-16]!
+ *      mov x25, sp
+ *      mov tcc, #0
+ *      // PROLOGUE_OFFSET
+ */
+
+#define BTI_INSNS (IS_ENABLED(CONFIG_ARM64_BTI_KERNEL) ? 1 : 0)
+#define PAC_INSNS (IS_ENABLED(CONFIG_ARM64_PTR_AUTH_KERNEL) ? 1 : 0)
+
+/* Offset of nop instruction in bpf prog entry to be poked */
+#define POKE_OFFSET (BTI_INSNS + 1)
+
+/* Tail call offset to jump into */
+#define PROLOGUE_OFFSET (BTI_INSNS + 2 + PAC_INSNS + 8)
+
+static int build_prologue(struct jit_ctx *ctx, bool ebpf_from_cbpf)
+{
+	const struct bpf_prog *prog = ctx->prog;
+	const bool is_main_prog = prog->aux->func_idx == 0;
+	const u8 r6 = bpf2a64[BPF_REG_6];
+	const u8 r7 = bpf2a64[BPF_REG_7];
+	const u8 r8 = bpf2a64[BPF_REG_8];
+	const u8 r9 = bpf2a64[BPF_REG_9];
+	const u8 fp = bpf2a64[BPF_REG_FP];
+	const u8 tcc = bpf2a64[TCALL_CNT];
+	const u8 fpb = bpf2a64[FP_BOTTOM];
+	const int idx0 = ctx->idx;
+	int cur_offset;
+
+	/*
+	 * BPF prog stack layout
+	 *
+	 *                         high
+	 * original A64_SP =>   0:+-----+ BPF prologue
+	 *                        |FP/LR|
+	 * current A64_FP =>  -16:+-----+
+	 *                        | ... | callee saved registers
+	 * BPF fp register => -64:+-----+ <= (BPF_FP)
+	 *                        |     |
+	 *                        | ... | BPF prog stack
+	 *                        |     |
+	 *                        +-----+ <= (BPF_FP - prog->aux->stack_depth)
+	 *                        |RSVD | padding
+	 * current A64_SP =>      +-----+ <= (BPF_FP - ctx->stack_size)
+	 *                        |     |
+	 *                        | ... | Function call stack
+	 *                        |     |
+	 *                        +-----+
+	 *                          low
+	 *
+	 */
+
+	/* bpf function may be invoked by 3 instruction types:
+	 * 1. bl, attached via freplace to bpf prog via short jump
+	 * 2. br, attached via freplace to bpf prog via long jump
+	 * 3. blr, working as a function pointer, used by emit_call.
+	 * So BTI_JC should used here to support both br and blr.
+	 */
+	emit_bti(A64_BTI_JC, ctx);
+
+	emit(A64_MOV(1, A64_R(9), A64_LR), ctx);
+	emit(A64_NOP, ctx);
+
+	/* Sign lr */
+	if (IS_ENABLED(CONFIG_ARM64_PTR_AUTH_KERNEL))
+		emit(A64_PACIASP, ctx);
+
+	/* Save FP and LR registers to stay align with ARM64 AAPCS */
+	emit(A64_PUSH(A64_FP, A64_LR, A64_SP), ctx);
+	emit(A64_MOV(1, A64_FP, A64_SP), ctx);
+
+	/* Save callee-saved registers */
+	emit(A64_PUSH(r6, r7, A64_SP), ctx);
+	emit(A64_PUSH(r8, r9, A64_SP), ctx);
+	emit(A64_PUSH(fp, tcc, A64_SP), ctx);
+	emit(A64_PUSH(fpb, A64_R(28), A64_SP), ctx);
+
+	/* Set up BPF prog stack base register */
+	emit(A64_MOV(1, fp, A64_SP), ctx);
+
+	if (!ebpf_from_cbpf && is_main_prog) {
+		/* Initialize tail_call_cnt */
+		emit(A64_MOVZ(1, tcc, 0, 0), ctx);
+
+		cur_offset = ctx->idx - idx0;
+		if (cur_offset != PROLOGUE_OFFSET) {
+			pr_err_once("PROLOGUE_OFFSET = %d, expected %d!\n",
+				    cur_offset, PROLOGUE_OFFSET);
+			return -1;
+		}
+
+		/* BTI landing pad for the tail call, done with a BR */
+		emit_bti(A64_BTI_J, ctx);
+	}
+
+	emit(A64_SUB_I(1, fpb, fp, ctx->fpb_offset), ctx);
+
+	/* Stack must be multiples of 16B */
+	ctx->stack_size = round_up(prog->aux->stack_depth, 16);
+
+	/* Set up function call stack */
+	emit(A64_SUB_I(1, A64_SP, A64_SP, ctx->stack_size), ctx);
+	return 0;
+}
+
+static int out_offset = -1; /* initialized on the first pass of build_body() */
+static int emit_bpf_tail_call(struct jit_ctx *ctx)
+{
+	/* bpf_tail_call(void *prog_ctx, struct bpf_array *array, u64 index) */
+	const u8 r2 = bpf2a64[BPF_REG_2];
+	const u8 r3 = bpf2a64[BPF_REG_3];
+
+	const u8 tmp = bpf2a64[TMP_REG_1];
+	const u8 prg = bpf2a64[TMP_REG_2];
+	const u8 tcc = bpf2a64[TCALL_CNT];
+	const int idx0 = ctx->idx;
+#define cur_offset (ctx->idx - idx0)
+#define jmp_offset (out_offset - (cur_offset))
+	size_t off;
+
+	/* if (index >= array->map.max_entries)
+	 *     goto out;
+	 */
+	off = offsetof(struct bpf_array, map.max_entries);
+	emit_a64_mov_i64(tmp, off, ctx);
+	emit(A64_LDR32(tmp, r2, tmp), ctx);
+	emit(A64_MOV(0, r3, r3), ctx);
+	emit(A64_CMP(0, r3, tmp), ctx);
+	emit(A64_B_(A64_COND_CS, jmp_offset), ctx);
+
+	/*
+	 * if (tail_call_cnt >= MAX_TAIL_CALL_CNT)
+	 *     goto out;
+	 * tail_call_cnt++;
+	 */
+	emit_a64_mov_i64(tmp, MAX_TAIL_CALL_CNT, ctx);
+	emit(A64_CMP(1, tcc, tmp), ctx);
+	emit(A64_B_(A64_COND_CS, jmp_offset), ctx);
+	emit(A64_ADD_I(1, tcc, tcc, 1), ctx);
+
+	/* prog = array->ptrs[index];
+	 * if (prog == NULL)
+	 *     goto out;
+	 */
+	off = offsetof(struct bpf_array, ptrs);
+	emit_a64_mov_i64(tmp, off, ctx);
+	emit(A64_ADD(1, tmp, r2, tmp), ctx);
+	emit(A64_LSL(1, prg, r3, 3), ctx);
+	emit(A64_LDR64(prg, tmp, prg), ctx);
+	emit(A64_CBZ(1, prg, jmp_offset), ctx);
+
+	/* goto *(prog->bpf_func + prologue_offset); */
+	off = offsetof(struct bpf_prog, bpf_func);
+	emit_a64_mov_i64(tmp, off, ctx);
+	emit(A64_LDR64(tmp, prg, tmp), ctx);
+	emit(A64_ADD_I(1, tmp, tmp, sizeof(u32) * PROLOGUE_OFFSET), ctx);
+	emit(A64_ADD_I(1, A64_SP, A64_SP, ctx->stack_size), ctx);
+	emit(A64_BR(tmp), ctx);
+
+	/* out: */
+	if (out_offset == -1)
+		out_offset = cur_offset;
+	if (cur_offset != out_offset) {
+		pr_err_once("tail_call out_offset = %d, expected %d!\n",
+			    cur_offset, out_offset);
+		return -1;
+	}
+	return 0;
+#undef cur_offset
+#undef jmp_offset
+}
+
+#ifdef CONFIG_ARM64_LSE_ATOMICS
+static int emit_lse_atomic(const struct bpf_insn *insn, struct jit_ctx *ctx)
+{
+	const u8 code = insn->code;
+	const u8 dst = bpf2a64[insn->dst_reg];
+	const u8 src = bpf2a64[insn->src_reg];
+	const u8 tmp = bpf2a64[TMP_REG_1];
+	const u8 tmp2 = bpf2a64[TMP_REG_2];
+	const bool isdw = BPF_SIZE(code) == BPF_DW;
+	const s16 off = insn->off;
+	u8 reg;
+
+	if (!off) {
+		reg = dst;
+	} else {
+		emit_a64_mov_i(1, tmp, off, ctx);
+		emit(A64_ADD(1, tmp, tmp, dst), ctx);
+		reg = tmp;
+	}
+
+	switch (insn->imm) {
+	/* lock *(u32/u64 *)(dst_reg + off) <op>= src_reg */
+	case BPF_ADD:
+		emit(A64_STADD(isdw, reg, src), ctx);
+		break;
+	case BPF_AND:
+		emit(A64_MVN(isdw, tmp2, src), ctx);
+		emit(A64_STCLR(isdw, reg, tmp2), ctx);
+		break;
+	case BPF_OR:
+		emit(A64_STSET(isdw, reg, src), ctx);
+		break;
+	case BPF_XOR:
+		emit(A64_STEOR(isdw, reg, src), ctx);
+		break;
+	/* src_reg = atomic_fetch_<op>(dst_reg + off, src_reg) */
+	case BPF_ADD | BPF_FETCH:
+		emit(A64_LDADDAL(isdw, src, reg, src), ctx);
+		break;
+	case BPF_AND | BPF_FETCH:
+		emit(A64_MVN(isdw, tmp2, src), ctx);
+		emit(A64_LDCLRAL(isdw, src, reg, tmp2), ctx);
+		break;
+	case BPF_OR | BPF_FETCH:
+		emit(A64_LDSETAL(isdw, src, reg, src), ctx);
+		break;
+	case BPF_XOR | BPF_FETCH:
+		emit(A64_LDEORAL(isdw, src, reg, src), ctx);
+		break;
+	/* src_reg = atomic_xchg(dst_reg + off, src_reg); */
+	case BPF_XCHG:
+		emit(A64_SWPAL(isdw, src, reg, src), ctx);
+		break;
+	/* r0 = atomic_cmpxchg(dst_reg + off, r0, src_reg); */
+	case BPF_CMPXCHG:
+		emit(A64_CASAL(isdw, src, reg, bpf2a64[BPF_REG_0]), ctx);
+		break;
+	default:
+		pr_err_once("unknown atomic op code %02x\n", insn->imm);
+		return -EINVAL;
+	}
+
+	return 0;
+}
+#else
+static inline int emit_lse_atomic(const struct bpf_insn *insn, struct jit_ctx *ctx)
+{
+	return -EINVAL;
+}
+#endif
+
+static int emit_ll_sc_atomic(const struct bpf_insn *insn, struct jit_ctx *ctx)
+{
+	const u8 code = insn->code;
+	const u8 dst = bpf2a64[insn->dst_reg];
+	const u8 src = bpf2a64[insn->src_reg];
+	const u8 tmp = bpf2a64[TMP_REG_1];
+	const u8 tmp2 = bpf2a64[TMP_REG_2];
+	const u8 tmp3 = bpf2a64[TMP_REG_3];
+	const int i = insn - ctx->prog->insnsi;
+	const s32 imm = insn->imm;
+	const s16 off = insn->off;
+	const bool isdw = BPF_SIZE(code) == BPF_DW;
+	u8 reg;
+	s32 jmp_offset;
+
+	if (!off) {
+		reg = dst;
+	} else {
+		emit_a64_mov_i(1, tmp, off, ctx);
+		emit(A64_ADD(1, tmp, tmp, dst), ctx);
+		reg = tmp;
+	}
+
+	if (imm == BPF_ADD || imm == BPF_AND ||
+	    imm == BPF_OR || imm == BPF_XOR) {
+		/* lock *(u32/u64 *)(dst_reg + off) <op>= src_reg */
+		emit(A64_LDXR(isdw, tmp2, reg), ctx);
+		if (imm == BPF_ADD)
+			emit(A64_ADD(isdw, tmp2, tmp2, src), ctx);
+		else if (imm == BPF_AND)
+			emit(A64_AND(isdw, tmp2, tmp2, src), ctx);
+		else if (imm == BPF_OR)
+			emit(A64_ORR(isdw, tmp2, tmp2, src), ctx);
+		else
+			emit(A64_EOR(isdw, tmp2, tmp2, src), ctx);
+		emit(A64_STXR(isdw, tmp2, reg, tmp3), ctx);
+		jmp_offset = -3;
+		check_imm19(jmp_offset);
+		emit(A64_CBNZ(0, tmp3, jmp_offset), ctx);
+	} else if (imm == (BPF_ADD | BPF_FETCH) ||
+		   imm == (BPF_AND | BPF_FETCH) ||
+		   imm == (BPF_OR | BPF_FETCH) ||
+		   imm == (BPF_XOR | BPF_FETCH)) {
+		/* src_reg = atomic_fetch_<op>(dst_reg + off, src_reg) */
+		const u8 ax = bpf2a64[BPF_REG_AX];
+
+		emit(A64_MOV(isdw, ax, src), ctx);
+		emit(A64_LDXR(isdw, src, reg), ctx);
+		if (imm == (BPF_ADD | BPF_FETCH))
+			emit(A64_ADD(isdw, tmp2, src, ax), ctx);
+		else if (imm == (BPF_AND | BPF_FETCH))
+			emit(A64_AND(isdw, tmp2, src, ax), ctx);
+		else if (imm == (BPF_OR | BPF_FETCH))
+			emit(A64_ORR(isdw, tmp2, src, ax), ctx);
+		else
+			emit(A64_EOR(isdw, tmp2, src, ax), ctx);
+		emit(A64_STLXR(isdw, tmp2, reg, tmp3), ctx);
+		jmp_offset = -3;
+		check_imm19(jmp_offset);
+		emit(A64_CBNZ(0, tmp3, jmp_offset), ctx);
+		emit(A64_DMB_ISH, ctx);
+	} else if (imm == BPF_XCHG) {
+		/* src_reg = atomic_xchg(dst_reg + off, src_reg); */
+		emit(A64_MOV(isdw, tmp2, src), ctx);
+		emit(A64_LDXR(isdw, src, reg), ctx);
+		emit(A64_STLXR(isdw, tmp2, reg, tmp3), ctx);
+		jmp_offset = -2;
+		check_imm19(jmp_offset);
+		emit(A64_CBNZ(0, tmp3, jmp_offset), ctx);
+		emit(A64_DMB_ISH, ctx);
+	} else if (imm == BPF_CMPXCHG) {
+		/* r0 = atomic_cmpxchg(dst_reg + off, r0, src_reg); */
+		const u8 r0 = bpf2a64[BPF_REG_0];
+
+		emit(A64_MOV(isdw, tmp2, r0), ctx);
+		emit(A64_LDXR(isdw, r0, reg), ctx);
+		emit(A64_EOR(isdw, tmp3, r0, tmp2), ctx);
+		jmp_offset = 4;
+		check_imm19(jmp_offset);
+		emit(A64_CBNZ(isdw, tmp3, jmp_offset), ctx);
+		emit(A64_STLXR(isdw, src, reg, tmp3), ctx);
+		jmp_offset = -4;
+		check_imm19(jmp_offset);
+		emit(A64_CBNZ(0, tmp3, jmp_offset), ctx);
+		emit(A64_DMB_ISH, ctx);
+	} else {
+		pr_err_once("unknown atomic op code %02x\n", imm);
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+void dummy_tramp(void);
+
+asm (
+"	.pushsection .text, \"ax\", @progbits\n"
+"	.global dummy_tramp\n"
+"	.type dummy_tramp, %function\n"
+"dummy_tramp:"
+#if IS_ENABLED(CONFIG_ARM64_BTI_KERNEL)
+"	bti j\n" /* dummy_tramp is called via "br x10" */
+#endif
+"	mov x10, x30\n"
+"	mov x30, x9\n"
+"	ret x10\n"
+"	.size dummy_tramp, .-dummy_tramp\n"
+"	.popsection\n"
+);
+
+/* build a plt initialized like this:
+ *
+ * plt:
+ *      ldr tmp, target
+ *      br tmp
+ * target:
+ *      .quad dummy_tramp
+ *
+ * when a long jump trampoline is attached, target is filled with the
+ * trampoline address, and when the trampoline is removed, target is
+ * restored to dummy_tramp address.
+ */
+static void build_plt(struct jit_ctx *ctx)
+{
+	const u8 tmp = bpf2a64[TMP_REG_1];
+	struct bpf_plt *plt = NULL;
+
+	/* make sure target is 64-bit aligned */
+	if ((ctx->idx + PLT_TARGET_OFFSET / AARCH64_INSN_SIZE) % 2)
+		emit(A64_NOP, ctx);
+
+	plt = (struct bpf_plt *)(ctx->image + ctx->idx);
+	/* plt is called via bl, no BTI needed here */
+	emit(A64_LDR64LIT(tmp, 2 * AARCH64_INSN_SIZE), ctx);
+	emit(A64_BR(tmp), ctx);
+
+	if (ctx->image)
+		plt->target = (u64)&dummy_tramp;
+}
+
+static void build_epilogue(struct jit_ctx *ctx)
+{
+	const u8 r0 = bpf2a64[BPF_REG_0];
+	const u8 r6 = bpf2a64[BPF_REG_6];
+	const u8 r7 = bpf2a64[BPF_REG_7];
+	const u8 r8 = bpf2a64[BPF_REG_8];
+	const u8 r9 = bpf2a64[BPF_REG_9];
+	const u8 fp = bpf2a64[BPF_REG_FP];
+	const u8 fpb = bpf2a64[FP_BOTTOM];
+
+	/* We're done with BPF stack */
+	emit(A64_ADD_I(1, A64_SP, A64_SP, ctx->stack_size), ctx);
+
+	/* Restore x27 and x28 */
+	emit(A64_POP(fpb, A64_R(28), A64_SP), ctx);
+	/* Restore fs (x25) and x26 */
+	emit(A64_POP(fp, A64_R(26), A64_SP), ctx);
+
+	/* Restore callee-saved register */
+	emit(A64_POP(r8, r9, A64_SP), ctx);
+	emit(A64_POP(r6, r7, A64_SP), ctx);
+
+	/* Restore FP/LR registers */
+	emit(A64_POP(A64_FP, A64_LR, A64_SP), ctx);
+
+	/* Set return value */
+	emit(A64_MOV(1, A64_R(0), r0), ctx);
+
+	/* Authenticate lr */
+	if (IS_ENABLED(CONFIG_ARM64_PTR_AUTH_KERNEL))
+		emit(A64_AUTIASP, ctx);
+
+	emit(A64_RET(A64_LR), ctx);
+}
+
+#define BPF_FIXUP_OFFSET_MASK	GENMASK(26, 0)
+#define BPF_FIXUP_REG_MASK	GENMASK(31, 27)
+
+bool ex_handler_bpf(const struct exception_table_entry *ex,
+		    struct pt_regs *regs)
+{
+	off_t offset = FIELD_GET(BPF_FIXUP_OFFSET_MASK, ex->fixup);
+	int dst_reg = FIELD_GET(BPF_FIXUP_REG_MASK, ex->fixup);
+
+	regs->regs[dst_reg] = 0;
+	regs->pc = (unsigned long)&ex->fixup - offset;
+	return true;
+}
+
+/* For accesses to BTF pointers, add an entry to the exception table */
+static int add_exception_handler(const struct bpf_insn *insn,
+				 struct jit_ctx *ctx,
+				 int dst_reg)
+{
+	off_t offset;
+	unsigned long pc;
+	struct exception_table_entry *ex;
+
+	if (!ctx->image)
+		/* First pass */
+		return 0;
+
+	if (BPF_MODE(insn->code) != BPF_PROBE_MEM)
+		return 0;
+
+	if (!ctx->prog->aux->extable ||
+	    WARN_ON_ONCE(ctx->exentry_idx >= ctx->prog->aux->num_exentries))
+		return -EINVAL;
+
+	ex = &ctx->prog->aux->extable[ctx->exentry_idx];
+	pc = (unsigned long)&ctx->image[ctx->idx - 1];
+
+	offset = pc - (long)&ex->insn;
+	if (WARN_ON_ONCE(offset >= 0 || offset < INT_MIN))
+		return -ERANGE;
+	ex->insn = offset;
+
+	/*
+	 * Since the extable follows the program, the fixup offset is always
+	 * negative and limited to BPF_JIT_REGION_SIZE. Store a positive value
+	 * to keep things simple, and put the destination register in the upper
+	 * bits. We don't need to worry about buildtime or runtime sort
+	 * modifying the upper bits because the table is already sorted, and
+	 * isn't part of the main exception table.
+	 */
+	offset = (long)&ex->fixup - (pc + AARCH64_INSN_SIZE);
+	if (!FIELD_FIT(BPF_FIXUP_OFFSET_MASK, offset))
+		return -ERANGE;
+
+	ex->fixup = FIELD_PREP(BPF_FIXUP_OFFSET_MASK, offset) |
+		    FIELD_PREP(BPF_FIXUP_REG_MASK, dst_reg);
+
+	ex->type = EX_TYPE_BPF;
+
+	ctx->exentry_idx++;
+	return 0;
+}
+
+/* JITs an eBPF instruction.
+ * Returns:
+ * 0  - successfully JITed an 8-byte eBPF instruction.
+ * >0 - successfully JITed a 16-byte eBPF instruction.
+ * <0 - failed to JIT.
+ */
+static int build_insn(const struct bpf_insn *insn, struct jit_ctx *ctx,
+		      bool extra_pass)
+{
+	const u8 code = insn->code;
+	const u8 dst = bpf2a64[insn->dst_reg];
+	const u8 src = bpf2a64[insn->src_reg];
+	const u8 tmp = bpf2a64[TMP_REG_1];
+	const u8 tmp2 = bpf2a64[TMP_REG_2];
+	const u8 fp = bpf2a64[BPF_REG_FP];
+	const u8 fpb = bpf2a64[FP_BOTTOM];
+	const s16 off = insn->off;
+	const s32 imm = insn->imm;
+	const int i = insn - ctx->prog->insnsi;
+	const bool is64 = BPF_CLASS(code) == BPF_ALU64 ||
+			  BPF_CLASS(code) == BPF_JMP;
+	u8 jmp_cond;
+	s32 jmp_offset;
+	u32 a64_insn;
+	u8 src_adj;
+	u8 dst_adj;
+	int off_adj;
+	int ret;
+
+	switch (code) {
+	/* dst = src */
+	case BPF_ALU | BPF_MOV | BPF_X:
+	case BPF_ALU64 | BPF_MOV | BPF_X:
+		emit(A64_MOV(is64, dst, src), ctx);
+		break;
+	/* dst = dst OP src */
+	case BPF_ALU | BPF_ADD | BPF_X:
+	case BPF_ALU64 | BPF_ADD | BPF_X:
+		emit(A64_ADD(is64, dst, dst, src), ctx);
+		break;
+	case BPF_ALU | BPF_SUB | BPF_X:
+	case BPF_ALU64 | BPF_SUB | BPF_X:
+		emit(A64_SUB(is64, dst, dst, src), ctx);
+		break;
+	case BPF_ALU | BPF_AND | BPF_X:
+	case BPF_ALU64 | BPF_AND | BPF_X:
+		emit(A64_AND(is64, dst, dst, src), ctx);
+		break;
+	case BPF_ALU | BPF_OR | BPF_X:
+	case BPF_ALU64 | BPF_OR | BPF_X:
+		emit(A64_ORR(is64, dst, dst, src), ctx);
+		break;
+	case BPF_ALU | BPF_XOR | BPF_X:
+	case BPF_ALU64 | BPF_XOR | BPF_X:
+		emit(A64_EOR(is64, dst, dst, src), ctx);
+		break;
+	case BPF_ALU | BPF_MUL | BPF_X:
+	case BPF_ALU64 | BPF_MUL | BPF_X:
+		emit(A64_MUL(is64, dst, dst, src), ctx);
+		break;
+	case BPF_ALU | BPF_DIV | BPF_X:
+	case BPF_ALU64 | BPF_DIV | BPF_X:
+		emit(A64_UDIV(is64, dst, dst, src), ctx);
+		break;
+	case BPF_ALU | BPF_MOD | BPF_X:
+	case BPF_ALU64 | BPF_MOD | BPF_X:
+		emit(A64_UDIV(is64, tmp, dst, src), ctx);
+		emit(A64_MSUB(is64, dst, dst, tmp, src), ctx);
+		break;
+	case BPF_ALU | BPF_LSH | BPF_X:
+	case BPF_ALU64 | BPF_LSH | BPF_X:
+		emit(A64_LSLV(is64, dst, dst, src), ctx);
+		break;
+	case BPF_ALU | BPF_RSH | BPF_X:
+	case BPF_ALU64 | BPF_RSH | BPF_X:
+		emit(A64_LSRV(is64, dst, dst, src), ctx);
+		break;
+	case BPF_ALU | BPF_ARSH | BPF_X:
+	case BPF_ALU64 | BPF_ARSH | BPF_X:
+		emit(A64_ASRV(is64, dst, dst, src), ctx);
+		break;
+	/* dst = -dst */
+	case BPF_ALU | BPF_NEG:
+	case BPF_ALU64 | BPF_NEG:
+		emit(A64_NEG(is64, dst, dst), ctx);
+		break;
+	/* dst = BSWAP##imm(dst) */
+	case BPF_ALU | BPF_END | BPF_FROM_LE:
+	case BPF_ALU | BPF_END | BPF_FROM_BE:
+#ifdef CONFIG_CPU_BIG_ENDIAN
+		if (BPF_SRC(code) == BPF_FROM_BE)
+			goto emit_bswap_uxt;
+#else /* !CONFIG_CPU_BIG_ENDIAN */
+		if (BPF_SRC(code) == BPF_FROM_LE)
+			goto emit_bswap_uxt;
+#endif
+		switch (imm) {
+		case 16:
+			emit(A64_REV16(is64, dst, dst), ctx);
+			/* zero-extend 16 bits into 64 bits */
+			emit(A64_UXTH(is64, dst, dst), ctx);
+			break;
+		case 32:
+			emit(A64_REV32(is64, dst, dst), ctx);
+			/* upper 32 bits already cleared */
+			break;
+		case 64:
+			emit(A64_REV64(dst, dst), ctx);
+			break;
+		}
+		break;
+emit_bswap_uxt:
+		switch (imm) {
+		case 16:
+			/* zero-extend 16 bits into 64 bits */
+			emit(A64_UXTH(is64, dst, dst), ctx);
+			break;
+		case 32:
+			/* zero-extend 32 bits into 64 bits */
+			emit(A64_UXTW(is64, dst, dst), ctx);
+			break;
+		case 64:
+			/* nop */
+			break;
+		}
+		break;
+	/* dst = imm */
+	case BPF_ALU | BPF_MOV | BPF_K:
+	case BPF_ALU64 | BPF_MOV | BPF_K:
+		emit_a64_mov_i(is64, dst, imm, ctx);
+		break;
+	/* dst = dst OP imm */
+	case BPF_ALU | BPF_ADD | BPF_K:
+	case BPF_ALU64 | BPF_ADD | BPF_K:
+		if (is_addsub_imm(imm)) {
+			emit(A64_ADD_I(is64, dst, dst, imm), ctx);
+		} else if (is_addsub_imm(-imm)) {
+			emit(A64_SUB_I(is64, dst, dst, -imm), ctx);
+		} else {
+			emit_a64_mov_i(is64, tmp, imm, ctx);
+			emit(A64_ADD(is64, dst, dst, tmp), ctx);
+		}
+		break;
+	case BPF_ALU | BPF_SUB | BPF_K:
+	case BPF_ALU64 | BPF_SUB | BPF_K:
+		if (is_addsub_imm(imm)) {
+			emit(A64_SUB_I(is64, dst, dst, imm), ctx);
+		} else if (is_addsub_imm(-imm)) {
+			emit(A64_ADD_I(is64, dst, dst, -imm), ctx);
+		} else {
+			emit_a64_mov_i(is64, tmp, imm, ctx);
+			emit(A64_SUB(is64, dst, dst, tmp), ctx);
+		}
+		break;
+	case BPF_ALU | BPF_AND | BPF_K:
+	case BPF_ALU64 | BPF_AND | BPF_K:
+		a64_insn = A64_AND_I(is64, dst, dst, imm);
+		if (a64_insn != AARCH64_BREAK_FAULT) {
+			emit(a64_insn, ctx);
+		} else {
+			emit_a64_mov_i(is64, tmp, imm, ctx);
+			emit(A64_AND(is64, dst, dst, tmp), ctx);
+		}
+		break;
+	case BPF_ALU | BPF_OR | BPF_K:
+	case BPF_ALU64 | BPF_OR | BPF_K:
+		a64_insn = A64_ORR_I(is64, dst, dst, imm);
+		if (a64_insn != AARCH64_BREAK_FAULT) {
+			emit(a64_insn, ctx);
+		} else {
+			emit_a64_mov_i(is64, tmp, imm, ctx);
+			emit(A64_ORR(is64, dst, dst, tmp), ctx);
+		}
+		break;
+	case BPF_ALU | BPF_XOR | BPF_K:
+	case BPF_ALU64 | BPF_XOR | BPF_K:
+		a64_insn = A64_EOR_I(is64, dst, dst, imm);
+		if (a64_insn != AARCH64_BREAK_FAULT) {
+			emit(a64_insn, ctx);
+		} else {
+			emit_a64_mov_i(is64, tmp, imm, ctx);
+			emit(A64_EOR(is64, dst, dst, tmp), ctx);
+		}
+		break;
+	case BPF_ALU | BPF_MUL | BPF_K:
+	case BPF_ALU64 | BPF_MUL | BPF_K:
+		emit_a64_mov_i(is64, tmp, imm, ctx);
+		emit(A64_MUL(is64, dst, dst, tmp), ctx);
+		break;
+	case BPF_ALU | BPF_DIV | BPF_K:
+	case BPF_ALU64 | BPF_DIV | BPF_K:
+		emit_a64_mov_i(is64, tmp, imm, ctx);
+		emit(A64_UDIV(is64, dst, dst, tmp), ctx);
+		break;
+	case BPF_ALU | BPF_MOD | BPF_K:
+	case BPF_ALU64 | BPF_MOD | BPF_K:
+		emit_a64_mov_i(is64, tmp2, imm, ctx);
+		emit(A64_UDIV(is64, tmp, dst, tmp2), ctx);
+		emit(A64_MSUB(is64, dst, dst, tmp, tmp2), ctx);
+		break;
+	case BPF_ALU | BPF_LSH | BPF_K:
+	case BPF_ALU64 | BPF_LSH | BPF_K:
+		emit(A64_LSL(is64, dst, dst, imm), ctx);
+		break;
+	case BPF_ALU | BPF_RSH | BPF_K:
+	case BPF_ALU64 | BPF_RSH | BPF_K:
+		emit(A64_LSR(is64, dst, dst, imm), ctx);
+		break;
+	case BPF_ALU | BPF_ARSH | BPF_K:
+	case BPF_ALU64 | BPF_ARSH | BPF_K:
+		emit(A64_ASR(is64, dst, dst, imm), ctx);
+		break;
+
+	/* JUMP off */
+	case BPF_JMP | BPF_JA:
+		jmp_offset = bpf2a64_offset(i, off, ctx);
+		check_imm26(jmp_offset);
+		emit(A64_B(jmp_offset), ctx);
+		break;
+	/* IF (dst COND src) JUMP off */
+	case BPF_JMP | BPF_JEQ | 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_JNE | 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_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_JNE | 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:
+		emit(A64_CMP(is64, dst, src), ctx);
+emit_cond_jmp:
+		jmp_offset = bpf2a64_offset(i, off, ctx);
+		check_imm19(jmp_offset);
+		switch (BPF_OP(code)) {
+		case BPF_JEQ:
+			jmp_cond = A64_COND_EQ;
+			break;
+		case BPF_JGT:
+			jmp_cond = A64_COND_HI;
+			break;
+		case BPF_JLT:
+			jmp_cond = A64_COND_CC;
+			break;
+		case BPF_JGE:
+			jmp_cond = A64_COND_CS;
+			break;
+		case BPF_JLE:
+			jmp_cond = A64_COND_LS;
+			break;
+		case BPF_JSET:
+		case BPF_JNE:
+			jmp_cond = A64_COND_NE;
+			break;
+		case BPF_JSGT:
+			jmp_cond = A64_COND_GT;
+			break;
+		case BPF_JSLT:
+			jmp_cond = A64_COND_LT;
+			break;
+		case BPF_JSGE:
+			jmp_cond = A64_COND_GE;
+			break;
+		case BPF_JSLE:
+			jmp_cond = A64_COND_LE;
+			break;
+		default:
+			return -EFAULT;
+		}
+		emit(A64_B_(jmp_cond, jmp_offset), ctx);
+		break;
+	case BPF_JMP | BPF_JSET | BPF_X:
+	case BPF_JMP32 | BPF_JSET | BPF_X:
+		emit(A64_TST(is64, dst, src), ctx);
+		goto emit_cond_jmp;
+	/* IF (dst COND imm) JUMP off */
+	case BPF_JMP | BPF_JEQ | 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_JNE | 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_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_JNE | 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:
+		if (is_addsub_imm(imm)) {
+			emit(A64_CMP_I(is64, dst, imm), ctx);
+		} else if (is_addsub_imm(-imm)) {
+			emit(A64_CMN_I(is64, dst, -imm), ctx);
+		} else {
+			emit_a64_mov_i(is64, tmp, imm, ctx);
+			emit(A64_CMP(is64, dst, tmp), ctx);
+		}
+		goto emit_cond_jmp;
+	case BPF_JMP | BPF_JSET | BPF_K:
+	case BPF_JMP32 | BPF_JSET | BPF_K:
+		a64_insn = A64_TST_I(is64, dst, imm);
+		if (a64_insn != AARCH64_BREAK_FAULT) {
+			emit(a64_insn, ctx);
+		} else {
+			emit_a64_mov_i(is64, tmp, imm, ctx);
+			emit(A64_TST(is64, dst, tmp), ctx);
+		}
+		goto emit_cond_jmp;
+	/* function call */
+	case BPF_JMP | BPF_CALL:
+	{
+		const u8 r0 = bpf2a64[BPF_REG_0];
+		bool func_addr_fixed;
+		u64 func_addr;
+
+		ret = bpf_jit_get_func_addr(ctx->prog, insn, extra_pass,
+					    &func_addr, &func_addr_fixed);
+		if (ret < 0)
+			return ret;
+		emit_call(func_addr, ctx);
+		emit(A64_MOV(1, r0, A64_R(0)), ctx);
+		break;
+	}
+	/* tail call */
+	case BPF_JMP | BPF_TAIL_CALL:
+		if (emit_bpf_tail_call(ctx))
+			return -EFAULT;
+		break;
+	/* function return */
+	case BPF_JMP | BPF_EXIT:
+		/* Optimization: when last instruction is EXIT,
+		   simply fallthrough to epilogue. */
+		if (i == ctx->prog->len - 1)
+			break;
+		jmp_offset = epilogue_offset(ctx);
+		check_imm26(jmp_offset);
+		emit(A64_B(jmp_offset), ctx);
+		break;
+
+	/* dst = imm64 */
+	case BPF_LD | BPF_IMM | BPF_DW:
+	{
+		const struct bpf_insn insn1 = insn[1];
+		u64 imm64;
+
+		imm64 = (u64)insn1.imm << 32 | (u32)imm;
+		if (bpf_pseudo_func(insn))
+			emit_addr_mov_i64(dst, imm64, ctx);
+		else
+			emit_a64_mov_i64(dst, imm64, ctx);
+
+		return 1;
+	}
+
+	/* LDX: dst = *(size *)(src + off) */
+	case BPF_LDX | BPF_MEM | BPF_W:
+	case BPF_LDX | BPF_MEM | BPF_H:
+	case BPF_LDX | BPF_MEM | BPF_B:
+	case BPF_LDX | BPF_MEM | BPF_DW:
+	case BPF_LDX | BPF_PROBE_MEM | BPF_DW:
+	case BPF_LDX | BPF_PROBE_MEM | BPF_W:
+	case BPF_LDX | BPF_PROBE_MEM | BPF_H:
+	case BPF_LDX | BPF_PROBE_MEM | BPF_B:
+		if (ctx->fpb_offset > 0 && src == fp) {
+			src_adj = fpb;
+			off_adj = off + ctx->fpb_offset;
+		} else {
+			src_adj = src;
+			off_adj = off;
+		}
+		switch (BPF_SIZE(code)) {
+		case BPF_W:
+			if (is_lsi_offset(off_adj, 2)) {
+				emit(A64_LDR32I(dst, src_adj, off_adj), ctx);
+			} else {
+				emit_a64_mov_i(1, tmp, off, ctx);
+				emit(A64_LDR32(dst, src, tmp), ctx);
+			}
+			break;
+		case BPF_H:
+			if (is_lsi_offset(off_adj, 1)) {
+				emit(A64_LDRHI(dst, src_adj, off_adj), ctx);
+			} else {
+				emit_a64_mov_i(1, tmp, off, ctx);
+				emit(A64_LDRH(dst, src, tmp), ctx);
+			}
+			break;
+		case BPF_B:
+			if (is_lsi_offset(off_adj, 0)) {
+				emit(A64_LDRBI(dst, src_adj, off_adj), ctx);
+			} else {
+				emit_a64_mov_i(1, tmp, off, ctx);
+				emit(A64_LDRB(dst, src, tmp), ctx);
+			}
+			break;
+		case BPF_DW:
+			if (is_lsi_offset(off_adj, 3)) {
+				emit(A64_LDR64I(dst, src_adj, off_adj), ctx);
+			} else {
+				emit_a64_mov_i(1, tmp, off, ctx);
+				emit(A64_LDR64(dst, src, tmp), ctx);
+			}
+			break;
+		}
+
+		ret = add_exception_handler(insn, ctx, dst);
+		if (ret)
+			return ret;
+		break;
+
+	/* speculation barrier */
+	case BPF_ST | BPF_NOSPEC:
+		/*
+		 * Nothing required here.
+		 *
+		 * In case of arm64, we rely on the firmware mitigation of
+		 * Speculative Store Bypass as controlled via the ssbd kernel
+		 * parameter. Whenever the mitigation is enabled, it works
+		 * for all of the kernel code with no need to provide any
+		 * additional instructions.
+		 */
+		break;
+
+	/* ST: *(size *)(dst + off) = imm */
+	case BPF_ST | BPF_MEM | BPF_W:
+	case BPF_ST | BPF_MEM | BPF_H:
+	case BPF_ST | BPF_MEM | BPF_B:
+	case BPF_ST | BPF_MEM | BPF_DW:
+		if (ctx->fpb_offset > 0 && dst == fp) {
+			dst_adj = fpb;
+			off_adj = off + ctx->fpb_offset;
+		} else {
+			dst_adj = dst;
+			off_adj = off;
+		}
+		/* Load imm to a register then store it */
+		emit_a64_mov_i(1, tmp, imm, ctx);
+		switch (BPF_SIZE(code)) {
+		case BPF_W:
+			if (is_lsi_offset(off_adj, 2)) {
+				emit(A64_STR32I(tmp, dst_adj, off_adj), ctx);
+			} else {
+				emit_a64_mov_i(1, tmp2, off, ctx);
+				emit(A64_STR32(tmp, dst, tmp2), ctx);
+			}
+			break;
+		case BPF_H:
+			if (is_lsi_offset(off_adj, 1)) {
+				emit(A64_STRHI(tmp, dst_adj, off_adj), ctx);
+			} else {
+				emit_a64_mov_i(1, tmp2, off, ctx);
+				emit(A64_STRH(tmp, dst, tmp2), ctx);
+			}
+			break;
+		case BPF_B:
+			if (is_lsi_offset(off_adj, 0)) {
+				emit(A64_STRBI(tmp, dst_adj, off_adj), ctx);
+			} else {
+				emit_a64_mov_i(1, tmp2, off, ctx);
+				emit(A64_STRB(tmp, dst, tmp2), ctx);
+			}
+			break;
+		case BPF_DW:
+			if (is_lsi_offset(off_adj, 3)) {
+				emit(A64_STR64I(tmp, dst_adj, off_adj), ctx);
+			} else {
+				emit_a64_mov_i(1, tmp2, off, ctx);
+				emit(A64_STR64(tmp, dst, tmp2), ctx);
+			}
+			break;
+		}
+		break;
+
+	/* STX: *(size *)(dst + off) = src */
+	case BPF_STX | BPF_MEM | BPF_W:
+	case BPF_STX | BPF_MEM | BPF_H:
+	case BPF_STX | BPF_MEM | BPF_B:
+	case BPF_STX | BPF_MEM | BPF_DW:
+		if (ctx->fpb_offset > 0 && dst == fp) {
+			dst_adj = fpb;
+			off_adj = off + ctx->fpb_offset;
+		} else {
+			dst_adj = dst;
+			off_adj = off;
+		}
+		switch (BPF_SIZE(code)) {
+		case BPF_W:
+			if (is_lsi_offset(off_adj, 2)) {
+				emit(A64_STR32I(src, dst_adj, off_adj), ctx);
+			} else {
+				emit_a64_mov_i(1, tmp, off, ctx);
+				emit(A64_STR32(src, dst, tmp), ctx);
+			}
+			break;
+		case BPF_H:
+			if (is_lsi_offset(off_adj, 1)) {
+				emit(A64_STRHI(src, dst_adj, off_adj), ctx);
+			} else {
+				emit_a64_mov_i(1, tmp, off, ctx);
+				emit(A64_STRH(src, dst, tmp), ctx);
+			}
+			break;
+		case BPF_B:
+			if (is_lsi_offset(off_adj, 0)) {
+				emit(A64_STRBI(src, dst_adj, off_adj), ctx);
+			} else {
+				emit_a64_mov_i(1, tmp, off, ctx);
+				emit(A64_STRB(src, dst, tmp), ctx);
+			}
+			break;
+		case BPF_DW:
+			if (is_lsi_offset(off_adj, 3)) {
+				emit(A64_STR64I(src, dst_adj, off_adj), ctx);
+			} else {
+				emit_a64_mov_i(1, tmp, off, ctx);
+				emit(A64_STR64(src, dst, tmp), ctx);
+			}
+			break;
+		}
+		break;
+
+	case BPF_STX | BPF_ATOMIC | BPF_W:
+	case BPF_STX | BPF_ATOMIC | BPF_DW:
+		if (cpus_have_cap(ARM64_HAS_LSE_ATOMICS))
+			ret = emit_lse_atomic(insn, ctx);
+		else
+			ret = emit_ll_sc_atomic(insn, ctx);
+		if (ret)
+			return ret;
+		break;
+
+	default:
+		pr_err_once("unknown opcode %02x\n", code);
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+/*
+ * Return 0 if FP may change at runtime, otherwise find the minimum negative
+ * offset to FP, converts it to positive number, and align down to 8 bytes.
+ */
+static int find_fpb_offset(struct bpf_prog *prog)
+{
+	int i;
+	int offset = 0;
+
+	for (i = 0; i < prog->len; i++) {
+		const struct bpf_insn *insn = &prog->insnsi[i];
+		const u8 class = BPF_CLASS(insn->code);
+		const u8 mode = BPF_MODE(insn->code);
+		const u8 src = insn->src_reg;
+		const u8 dst = insn->dst_reg;
+		const s32 imm = insn->imm;
+		const s16 off = insn->off;
+
+		switch (class) {
+		case BPF_STX:
+		case BPF_ST:
+			/* fp holds atomic operation result */
+			if (class == BPF_STX && mode == BPF_ATOMIC &&
+			    ((imm == BPF_XCHG ||
+			      imm == (BPF_FETCH | BPF_ADD) ||
+			      imm == (BPF_FETCH | BPF_AND) ||
+			      imm == (BPF_FETCH | BPF_XOR) ||
+			      imm == (BPF_FETCH | BPF_OR)) &&
+			     src == BPF_REG_FP))
+				return 0;
+
+			if (mode == BPF_MEM && dst == BPF_REG_FP &&
+			    off < offset)
+				offset = insn->off;
+			break;
+
+		case BPF_JMP32:
+		case BPF_JMP:
+			break;
+
+		case BPF_LDX:
+		case BPF_LD:
+			/* fp holds load result */
+			if (dst == BPF_REG_FP)
+				return 0;
+
+			if (class == BPF_LDX && mode == BPF_MEM &&
+			    src == BPF_REG_FP && off < offset)
+				offset = off;
+			break;
+
+		case BPF_ALU:
+		case BPF_ALU64:
+		default:
+			/* fp holds ALU result */
+			if (dst == BPF_REG_FP)
+				return 0;
+		}
+	}
+
+	if (offset < 0) {
+		/*
+		 * safely be converted to a positive 'int', since insn->off
+		 * is 's16'
+		 */
+		offset = -offset;
+		/* align down to 8 bytes */
+		offset = ALIGN_DOWN(offset, 8);
+	}
+
+	return offset;
+}
+
+static int build_body(struct jit_ctx *ctx, bool extra_pass)
+{
+	const struct bpf_prog *prog = ctx->prog;
+	int i;
+
+	/*
+	 * - offset[0] offset of the end of prologue,
+	 *   start of the 1st instruction.
+	 * - offset[1] - offset of the end of 1st instruction,
+	 *   start of the 2nd instruction
+	 * [....]
+	 * - offset[3] - offset of the end of 3rd instruction,
+	 *   start of 4th instruction
+	 */
+	for (i = 0; i < prog->len; i++) {
+		const struct bpf_insn *insn = &prog->insnsi[i];
+		int ret;
+
+		if (ctx->image == NULL)
+			ctx->offset[i] = ctx->idx;
+		ret = build_insn(insn, ctx, extra_pass);
+		if (ret > 0) {
+			i++;
+			if (ctx->image == NULL)
+				ctx->offset[i] = ctx->idx;
+			continue;
+		}
+		if (ret)
+			return ret;
+	}
+	/*
+	 * offset is allocated with prog->len + 1 so fill in
+	 * the last element with the offset after the last
+	 * instruction (end of program)
+	 */
+	if (ctx->image == NULL)
+		ctx->offset[i] = ctx->idx;
+
+	return 0;
+}
+
+static int validate_code(struct jit_ctx *ctx)
+{
+	int i;
+
+	for (i = 0; i < ctx->idx; i++) {
+		u32 a64_insn = le32_to_cpu(ctx->image[i]);
+
+		if (a64_insn == AARCH64_BREAK_FAULT)
+			return -1;
+	}
+	return 0;
+}
+
+static int validate_ctx(struct jit_ctx *ctx)
+{
+	if (validate_code(ctx))
+		return -1;
+
+	if (WARN_ON_ONCE(ctx->exentry_idx != ctx->prog->aux->num_exentries))
+		return -1;
+
+	return 0;
+}
+
+static inline void bpf_flush_icache(void *start, void *end)
+{
+	flush_icache_range((unsigned long)start, (unsigned long)end);
+}
+
+struct arm64_jit_data {
+	struct bpf_binary_header *header;
+	u8 *image;
+	struct jit_ctx ctx;
+};
+
+struct bpf_prog *bpf_int_jit_compile(struct bpf_prog *prog)
+{
+	int image_size, prog_size, extable_size, extable_align, extable_offset;
+	struct bpf_prog *tmp, *orig_prog = prog;
+	struct bpf_binary_header *header;
+	struct arm64_jit_data *jit_data;
+	bool was_classic = bpf_prog_was_classic(prog);
+	bool tmp_blinded = false;
+	bool extra_pass = false;
+	struct jit_ctx ctx;
+	u8 *image_ptr;
+
+	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;
+	}
+	if (jit_data->ctx.offset) {
+		ctx = jit_data->ctx;
+		image_ptr = jit_data->image;
+		header = jit_data->header;
+		extra_pass = true;
+		prog_size = sizeof(u32) * ctx.idx;
+		goto skip_init_ctx;
+	}
+	memset(&ctx, 0, sizeof(ctx));
+	ctx.prog = prog;
+
+	ctx.offset = kvcalloc(prog->len + 1, sizeof(int), GFP_KERNEL);
+	if (ctx.offset == NULL) {
+		prog = orig_prog;
+		goto out_off;
+	}
+
+	ctx.fpb_offset = find_fpb_offset(prog);
+
+	/*
+	 * 1. Initial fake pass to compute ctx->idx and ctx->offset.
+	 *
+	 * BPF line info needs ctx->offset[i] to be the offset of
+	 * instruction[i] in jited image, so build prologue first.
+	 */
+	if (build_prologue(&ctx, was_classic)) {
+		prog = orig_prog;
+		goto out_off;
+	}
+
+	if (build_body(&ctx, extra_pass)) {
+		prog = orig_prog;
+		goto out_off;
+	}
+
+	ctx.epilogue_offset = ctx.idx;
+	build_epilogue(&ctx);
+	build_plt(&ctx);
+
+	extable_align = __alignof__(struct exception_table_entry);
+	extable_size = prog->aux->num_exentries *
+		sizeof(struct exception_table_entry);
+
+	/* Now we know the actual image size. */
+	prog_size = sizeof(u32) * ctx.idx;
+	/* also allocate space for plt target */
+	extable_offset = round_up(prog_size + PLT_TARGET_SIZE, extable_align);
+	image_size = extable_offset + extable_size;
+	header = bpf_jit_binary_alloc(image_size, &image_ptr,
+				      sizeof(u32), jit_fill_hole);
+	if (header == NULL) {
+		prog = orig_prog;
+		goto out_off;
+	}
+
+	/* 2. Now, the actual pass. */
+
+	ctx.image = (__le32 *)image_ptr;
+	if (extable_size)
+		prog->aux->extable = (void *)image_ptr + extable_offset;
+skip_init_ctx:
+	ctx.idx = 0;
+	ctx.exentry_idx = 0;
+
+	build_prologue(&ctx, was_classic);
+
+	if (build_body(&ctx, extra_pass)) {
+		bpf_jit_binary_free(header);
+		prog = orig_prog;
+		goto out_off;
+	}
+
+	build_epilogue(&ctx);
+	build_plt(&ctx);
+
+	/* 3. Extra pass to validate JITed code. */
+	if (validate_ctx(&ctx)) {
+		bpf_jit_binary_free(header);
+		prog = orig_prog;
+		goto out_off;
+	}
+
+	/* And we're done. */
+	if (bpf_jit_enable > 1)
+		bpf_jit_dump(prog->len, prog_size, 2, ctx.image);
+
+	bpf_flush_icache(header, ctx.image + ctx.idx);
+
+	if (!prog->is_func || extra_pass) {
+		if (extra_pass && ctx.idx != jit_data->ctx.idx) {
+			pr_err_once("multi-func JIT bug %d != %d\n",
+				    ctx.idx, jit_data->ctx.idx);
+			bpf_jit_binary_free(header);
+			prog->bpf_func = NULL;
+			prog->jited = 0;
+			prog->jited_len = 0;
+			goto out_off;
+		}
+		bpf_jit_binary_lock_ro(header);
+	} else {
+		jit_data->ctx = ctx;
+		jit_data->image = image_ptr;
+		jit_data->header = header;
+	}
+	prog->bpf_func = (void *)ctx.image;
+	prog->jited = 1;
+	prog->jited_len = prog_size;
+
+	if (!prog->is_func || extra_pass) {
+		int i;
+
+		/* offset[prog->len] is the size of program */
+		for (i = 0; i <= prog->len; i++)
+			ctx.offset[i] *= AARCH64_INSN_SIZE;
+		bpf_prog_fill_jited_linfo(prog, ctx.offset + 1);
+out_off:
+		kvfree(ctx.offset);
+		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;
+}
+
+u64 bpf_jit_alloc_exec_limit(void)
+{
+	return VMALLOC_END - VMALLOC_START;
+}
+
+void *bpf_jit_alloc_exec(unsigned long size)
+{
+	/* Memory is intended to be executable, reset the pointer tag. */
+	return kasan_reset_tag(vmalloc(size));
+}
+
+void bpf_jit_free_exec(void *addr)
+{
+	return vfree(addr);
+}
+
+/* Indicate the JIT backend supports mixing bpf2bpf and tailcalls. */
+bool bpf_jit_supports_subprog_tailcalls(void)
+{
+	return true;
+}
+
+static void invoke_bpf_prog(struct jit_ctx *ctx, struct bpf_tramp_link *l,
+			    int args_off, int retval_off, int run_ctx_off,
+			    bool save_ret)
+{
+	__le32 *branch;
+	u64 enter_prog;
+	u64 exit_prog;
+	struct bpf_prog *p = l->link.prog;
+	int cookie_off = offsetof(struct bpf_tramp_run_ctx, bpf_cookie);
+
+	enter_prog = (u64)bpf_trampoline_enter(p);
+	exit_prog = (u64)bpf_trampoline_exit(p);
+
+	if (l->cookie == 0) {
+		/* if cookie is zero, one instruction is enough to store it */
+		emit(A64_STR64I(A64_ZR, A64_SP, run_ctx_off + cookie_off), ctx);
+	} else {
+		emit_a64_mov_i64(A64_R(10), l->cookie, ctx);
+		emit(A64_STR64I(A64_R(10), A64_SP, run_ctx_off + cookie_off),
+		     ctx);
+	}
+
+	/* save p to callee saved register x19 to avoid loading p with mov_i64
+	 * each time.
+	 */
+	emit_addr_mov_i64(A64_R(19), (const u64)p, ctx);
+
+	/* arg1: prog */
+	emit(A64_MOV(1, A64_R(0), A64_R(19)), ctx);
+	/* arg2: &run_ctx */
+	emit(A64_ADD_I(1, A64_R(1), A64_SP, run_ctx_off), ctx);
+
+	emit_call(enter_prog, ctx);
+
+	/* if (__bpf_prog_enter(prog) == 0)
+	 *         goto skip_exec_of_prog;
+	 */
+	branch = ctx->image + ctx->idx;
+	emit(A64_NOP, ctx);
+
+	/* save return value to callee saved register x20 */
+	emit(A64_MOV(1, A64_R(20), A64_R(0)), ctx);
+
+	emit(A64_ADD_I(1, A64_R(0), A64_SP, args_off), ctx);
+	if (!p->jited)
+		emit_addr_mov_i64(A64_R(1), (const u64)p->insnsi, ctx);
+
+	emit_call((const u64)p->bpf_func, ctx);
+
+	if (save_ret)
+		emit(A64_STR64I(A64_R(0), A64_SP, retval_off), ctx);
+
+	if (ctx->image) {
+		int offset = &ctx->image[ctx->idx] - branch;
+		*branch = cpu_to_le32(A64_CBZ(1, A64_R(0), offset));
+	}
+
+	/* arg1: prog */
+	emit(A64_MOV(1, A64_R(0), A64_R(19)), ctx);
+	/* arg2: start time */
+	emit(A64_MOV(1, A64_R(1), A64_R(20)), ctx);
+	/* arg3: &run_ctx */
+	emit(A64_ADD_I(1, A64_R(2), A64_SP, run_ctx_off), ctx);
+
+	emit_call(exit_prog, ctx);
+}
+
+static void invoke_bpf_mod_ret(struct jit_ctx *ctx, struct bpf_tramp_links *tl,
+			       int args_off, int retval_off, int run_ctx_off,
+			       __le32 **branches)
+{
+	int i;
+
+	/* The first fmod_ret program will receive a garbage return value.
+	 * Set this to 0 to avoid confusing the program.
+	 */
+	emit(A64_STR64I(A64_ZR, A64_SP, retval_off), ctx);
+	for (i = 0; i < tl->nr_links; i++) {
+		invoke_bpf_prog(ctx, tl->links[i], args_off, retval_off,
+				run_ctx_off, true);
+		/* if (*(u64 *)(sp + retval_off) !=  0)
+		 *	goto do_fexit;
+		 */
+		emit(A64_LDR64I(A64_R(10), A64_SP, retval_off), ctx);
+		/* Save the location of branch, and generate a nop.
+		 * This nop will be replaced with a cbnz later.
+		 */
+		branches[i] = ctx->image + ctx->idx;
+		emit(A64_NOP, ctx);
+	}
+}
+
+static void save_args(struct jit_ctx *ctx, int args_off, int nargs)
+{
+	int i;
+
+	for (i = 0; i < nargs; i++) {
+		emit(A64_STR64I(i, A64_SP, args_off), ctx);
+		args_off += 8;
+	}
+}
+
+static void restore_args(struct jit_ctx *ctx, int args_off, int nargs)
+{
+	int i;
+
+	for (i = 0; i < nargs; i++) {
+		emit(A64_LDR64I(i, A64_SP, args_off), ctx);
+		args_off += 8;
+	}
+}
+
+/* Based on the x86's implementation of arch_prepare_bpf_trampoline().
+ *
+ * bpf prog and function entry before bpf trampoline hooked:
+ *   mov x9, lr
+ *   nop
+ *
+ * bpf prog and function entry after bpf trampoline hooked:
+ *   mov x9, lr
+ *   bl  <bpf_trampoline or plt>
+ *
+ */
+static int prepare_trampoline(struct jit_ctx *ctx, struct bpf_tramp_image *im,
+			      struct bpf_tramp_links *tlinks, void *orig_call,
+			      int nargs, u32 flags)
+{
+	int i;
+	int stack_size;
+	int retaddr_off;
+	int regs_off;
+	int retval_off;
+	int args_off;
+	int nargs_off;
+	int ip_off;
+	int 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];
+	bool save_ret;
+	__le32 **branches = NULL;
+
+	/* trampoline stack layout:
+	 *                  [ parent ip         ]
+	 *                  [ FP                ]
+	 * SP + retaddr_off [ self ip           ]
+	 *                  [ FP                ]
+	 *
+	 *                  [ padding           ] align SP to multiples of 16
+	 *
+	 *                  [ x20               ] callee saved reg x20
+	 * SP + regs_off    [ x19               ] callee saved reg x19
+	 *
+	 * SP + retval_off  [ return value      ] BPF_TRAMP_F_CALL_ORIG or
+	 *                                        BPF_TRAMP_F_RET_FENTRY_RET
+	 *
+	 *                  [ argN              ]
+	 *                  [ ...               ]
+	 * SP + args_off    [ arg1              ]
+	 *
+	 * SP + nargs_off   [ args count        ]
+	 *
+	 * SP + ip_off      [ traced function   ] BPF_TRAMP_F_IP_ARG flag
+	 *
+	 * SP + run_ctx_off [ bpf_tramp_run_ctx ]
+	 */
+
+	stack_size = 0;
+	run_ctx_off = stack_size;
+	/* room for bpf_tramp_run_ctx */
+	stack_size += round_up(sizeof(struct bpf_tramp_run_ctx), 8);
+
+	ip_off = stack_size;
+	/* room for IP address argument */
+	if (flags & BPF_TRAMP_F_IP_ARG)
+		stack_size += 8;
+
+	nargs_off = stack_size;
+	/* room for args count */
+	stack_size += 8;
+
+	args_off = stack_size;
+	/* room for args */
+	stack_size += nargs * 8;
+
+	/* room for return value */
+	retval_off = stack_size;
+	save_ret = flags & (BPF_TRAMP_F_CALL_ORIG | BPF_TRAMP_F_RET_FENTRY_RET);
+	if (save_ret)
+		stack_size += 8;
+
+	/* room for callee saved registers, currently x19 and x20 are used */
+	regs_off = stack_size;
+	stack_size += 16;
+
+	/* round up to multiples of 16 to avoid SPAlignmentFault */
+	stack_size = round_up(stack_size, 16);
+
+	/* return address locates above FP */
+	retaddr_off = stack_size + 8;
+
+	/* bpf trampoline may be invoked by 3 instruction types:
+	 * 1. bl, attached to bpf prog or kernel function via short jump
+	 * 2. br, attached to bpf prog or kernel function via long jump
+	 * 3. blr, working as a function pointer, used by struct_ops.
+	 * So BTI_JC should used here to support both br and blr.
+	 */
+	emit_bti(A64_BTI_JC, ctx);
+
+	/* frame for parent function */
+	emit(A64_PUSH(A64_FP, A64_R(9), A64_SP), ctx);
+	emit(A64_MOV(1, A64_FP, A64_SP), ctx);
+
+	/* frame for patched function */
+	emit(A64_PUSH(A64_FP, A64_LR, A64_SP), ctx);
+	emit(A64_MOV(1, A64_FP, A64_SP), ctx);
+
+	/* allocate stack space */
+	emit(A64_SUB_I(1, A64_SP, A64_SP, stack_size), ctx);
+
+	if (flags & BPF_TRAMP_F_IP_ARG) {
+		/* save ip address of the traced function */
+		emit_addr_mov_i64(A64_R(10), (const u64)orig_call, ctx);
+		emit(A64_STR64I(A64_R(10), A64_SP, ip_off), ctx);
+	}
+
+	/* save args count*/
+	emit(A64_MOVZ(1, A64_R(10), nargs, 0), ctx);
+	emit(A64_STR64I(A64_R(10), A64_SP, nargs_off), ctx);
+
+	/* save args */
+	save_args(ctx, args_off, nargs);
+
+	/* save callee saved registers */
+	emit(A64_STR64I(A64_R(19), A64_SP, regs_off), ctx);
+	emit(A64_STR64I(A64_R(20), A64_SP, regs_off + 8), ctx);
+
+	if (flags & BPF_TRAMP_F_CALL_ORIG) {
+		emit_addr_mov_i64(A64_R(0), (const u64)im, ctx);
+		emit_call((const u64)__bpf_tramp_enter, ctx);
+	}
+
+	for (i = 0; i < fentry->nr_links; i++)
+		invoke_bpf_prog(ctx, fentry->links[i], args_off,
+				retval_off, run_ctx_off,
+				flags & BPF_TRAMP_F_RET_FENTRY_RET);
+
+	if (fmod_ret->nr_links) {
+		branches = kcalloc(fmod_ret->nr_links, sizeof(__le32 *),
+				   GFP_KERNEL);
+		if (!branches)
+			return -ENOMEM;
+
+		invoke_bpf_mod_ret(ctx, fmod_ret, args_off, retval_off,
+				   run_ctx_off, branches);
+	}
+
+	if (flags & BPF_TRAMP_F_CALL_ORIG) {
+		restore_args(ctx, args_off, nargs);
+		/* call original func */
+		emit(A64_LDR64I(A64_R(10), A64_SP, retaddr_off), ctx);
+		emit(A64_ADR(A64_LR, AARCH64_INSN_SIZE * 2), ctx);
+		emit(A64_RET(A64_R(10)), ctx);
+		/* store return value */
+		emit(A64_STR64I(A64_R(0), A64_SP, retval_off), ctx);
+		/* reserve a nop for bpf_tramp_image_put */
+		im->ip_after_call = ctx->image + ctx->idx;
+		emit(A64_NOP, ctx);
+	}
+
+	/* update the branches saved in invoke_bpf_mod_ret with cbnz */
+	for (i = 0; i < fmod_ret->nr_links && ctx->image != NULL; i++) {
+		int offset = &ctx->image[ctx->idx] - branches[i];
+		*branches[i] = cpu_to_le32(A64_CBNZ(1, A64_R(10), offset));
+	}
+
+	for (i = 0; i < fexit->nr_links; i++)
+		invoke_bpf_prog(ctx, fexit->links[i], args_off, retval_off,
+				run_ctx_off, false);
+
+	if (flags & BPF_TRAMP_F_CALL_ORIG) {
+		im->ip_epilogue = ctx->image + ctx->idx;
+		emit_addr_mov_i64(A64_R(0), (const u64)im, ctx);
+		emit_call((const u64)__bpf_tramp_exit, ctx);
+	}
+
+	if (flags & BPF_TRAMP_F_RESTORE_REGS)
+		restore_args(ctx, args_off, nargs);
+
+	/* restore callee saved register x19 and x20 */
+	emit(A64_LDR64I(A64_R(19), A64_SP, regs_off), ctx);
+	emit(A64_LDR64I(A64_R(20), A64_SP, regs_off + 8), ctx);
+
+	if (save_ret)
+		emit(A64_LDR64I(A64_R(0), A64_SP, retval_off), ctx);
+
+	/* reset SP  */
+	emit(A64_MOV(1, A64_SP, A64_FP), ctx);
+
+	/* pop frames  */
+	emit(A64_POP(A64_FP, A64_LR, A64_SP), ctx);
+	emit(A64_POP(A64_FP, A64_R(9), A64_SP), ctx);
+
+	if (flags & BPF_TRAMP_F_SKIP_FRAME) {
+		/* skip patched function, return to parent */
+		emit(A64_MOV(1, A64_LR, A64_R(9)), ctx);
+		emit(A64_RET(A64_R(9)), ctx);
+	} else {
+		/* return to patched function */
+		emit(A64_MOV(1, A64_R(10), A64_LR), ctx);
+		emit(A64_MOV(1, A64_LR, A64_R(9)), ctx);
+		emit(A64_RET(A64_R(10)), ctx);
+	}
+
+	if (ctx->image)
+		bpf_flush_icache(ctx->image, ctx->image + ctx->idx);
+
+	kfree(branches);
+
+	return ctx->idx;
+}
+
+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 *orig_call)
+{
+	int i, ret;
+	int nargs = m->nr_args;
+	int max_insns = ((long)image_end - (long)image) / AARCH64_INSN_SIZE;
+	struct jit_ctx ctx = {
+		.image = NULL,
+		.idx = 0,
+	};
+
+	/* the first 8 arguments are passed by registers */
+	if (nargs > 8)
+		return -ENOTSUPP;
+
+	/* don't support struct argument */
+	for (i = 0; i < MAX_BPF_FUNC_ARGS; i++) {
+		if (m->arg_flags[i] & BTF_FMODEL_STRUCT_ARG)
+			return -ENOTSUPP;
+	}
+
+	ret = prepare_trampoline(&ctx, im, tlinks, orig_call, nargs, flags);
+	if (ret < 0)
+		return ret;
+
+	if (ret > max_insns)
+		return -EFBIG;
+
+	ctx.image = image;
+	ctx.idx = 0;
+
+	jit_fill_hole(image, (unsigned int)(image_end - image));
+	ret = prepare_trampoline(&ctx, im, tlinks, orig_call, nargs, flags);
+
+	if (ret > 0 && validate_code(&ctx) < 0)
+		ret = -EINVAL;
+
+	if (ret > 0)
+		ret *= AARCH64_INSN_SIZE;
+
+	return ret;
+}
+
+static bool is_long_jump(void *ip, void *target)
+{
+	long offset;
+
+	/* NULL target means this is a NOP */
+	if (!target)
+		return false;
+
+	offset = (long)target - (long)ip;
+	return offset < -SZ_128M || offset >= SZ_128M;
+}
+
+static int gen_branch_or_nop(enum aarch64_insn_branch_type type, void *ip,
+			     void *addr, void *plt, u32 *insn)
+{
+	void *target;
+
+	if (!addr) {
+		*insn = aarch64_insn_gen_nop();
+		return 0;
+	}
+
+	if (is_long_jump(ip, addr))
+		target = plt;
+	else
+		target = addr;
+
+	*insn = aarch64_insn_gen_branch_imm((unsigned long)ip,
+					    (unsigned long)target,
+					    type);
+
+	return *insn != AARCH64_BREAK_FAULT ? 0 : -EFAULT;
+}
+
+/* Replace the branch instruction from @ip to @old_addr in a bpf prog or a bpf
+ * trampoline with the branch instruction from @ip to @new_addr. If @old_addr
+ * or @new_addr is NULL, the old or new instruction is NOP.
+ *
+ * When @ip is the bpf prog entry, a bpf trampoline is being attached or
+ * detached. Since bpf trampoline and bpf prog are allocated separately with
+ * vmalloc, the address distance may exceed 128MB, the maximum branch range.
+ * So long jump should be handled.
+ *
+ * When a bpf prog is constructed, a plt pointing to empty trampoline
+ * dummy_tramp is placed at the end:
+ *
+ *      bpf_prog:
+ *              mov x9, lr
+ *              nop // patchsite
+ *              ...
+ *              ret
+ *
+ *      plt:
+ *              ldr x10, target
+ *              br x10
+ *      target:
+ *              .quad dummy_tramp // plt target
+ *
+ * This is also the state when no trampoline is attached.
+ *
+ * When a short-jump bpf trampoline is attached, the patchsite is patched
+ * to a bl instruction to the trampoline directly:
+ *
+ *      bpf_prog:
+ *              mov x9, lr
+ *              bl <short-jump bpf trampoline address> // patchsite
+ *              ...
+ *              ret
+ *
+ *      plt:
+ *              ldr x10, target
+ *              br x10
+ *      target:
+ *              .quad dummy_tramp // plt target
+ *
+ * When a long-jump bpf trampoline is attached, the plt target is filled with
+ * the trampoline address and the patchsite is patched to a bl instruction to
+ * the plt:
+ *
+ *      bpf_prog:
+ *              mov x9, lr
+ *              bl plt // patchsite
+ *              ...
+ *              ret
+ *
+ *      plt:
+ *              ldr x10, target
+ *              br x10
+ *      target:
+ *              .quad <long-jump bpf trampoline address> // plt target
+ *
+ * The dummy_tramp is used to prevent another CPU from jumping to unknown
+ * locations during the patching process, making the patching process easier.
+ */
+int bpf_arch_text_poke(void *ip, enum bpf_text_poke_type poke_type,
+		       void *old_addr, void *new_addr)
+{
+	int ret;
+	u32 old_insn;
+	u32 new_insn;
+	u32 replaced;
+	struct bpf_plt *plt = NULL;
+	unsigned long size = 0UL;
+	unsigned long offset = ~0UL;
+	enum aarch64_insn_branch_type branch_type;
+	char namebuf[KSYM_NAME_LEN];
+	void *image = NULL;
+	u64 plt_target = 0ULL;
+	bool poking_bpf_entry;
+
+	if (!__bpf_address_lookup((unsigned long)ip, &size, &offset, namebuf))
+		/* Only poking bpf text is supported. Since kernel function
+		 * entry is set up by ftrace, we reply on ftrace to poke kernel
+		 * functions.
+		 */
+		return -ENOTSUPP;
+
+	image = ip - offset;
+	/* zero offset means we're poking bpf prog entry */
+	poking_bpf_entry = (offset == 0UL);
+
+	/* bpf prog entry, find plt and the real patchsite */
+	if (poking_bpf_entry) {
+		/* plt locates at the end of bpf prog */
+		plt = image + size - PLT_TARGET_OFFSET;
+
+		/* skip to the nop instruction in bpf prog entry:
+		 * bti c // if BTI enabled
+		 * mov x9, x30
+		 * nop
+		 */
+		ip = image + POKE_OFFSET * AARCH64_INSN_SIZE;
+	}
+
+	/* long jump is only possible at bpf prog entry */
+	if (WARN_ON((is_long_jump(ip, new_addr) || is_long_jump(ip, old_addr)) &&
+		    !poking_bpf_entry))
+		return -EINVAL;
+
+	if (poke_type == BPF_MOD_CALL)
+		branch_type = AARCH64_INSN_BRANCH_LINK;
+	else
+		branch_type = AARCH64_INSN_BRANCH_NOLINK;
+
+	if (gen_branch_or_nop(branch_type, ip, old_addr, plt, &old_insn) < 0)
+		return -EFAULT;
+
+	if (gen_branch_or_nop(branch_type, ip, new_addr, plt, &new_insn) < 0)
+		return -EFAULT;
+
+	if (is_long_jump(ip, new_addr))
+		plt_target = (u64)new_addr;
+	else if (is_long_jump(ip, old_addr))
+		/* if the old target is a long jump and the new target is not,
+		 * restore the plt target to dummy_tramp, so there is always a
+		 * legal and harmless address stored in plt target, and we'll
+		 * never jump from plt to an unknown place.
+		 */
+		plt_target = (u64)&dummy_tramp;
+
+	if (plt_target) {
+		/* non-zero plt_target indicates we're patching a bpf prog,
+		 * which is read only.
+		 */
+		if (set_memory_rw(PAGE_MASK & ((uintptr_t)&plt->target), 1))
+			return -EFAULT;
+		WRITE_ONCE(plt->target, plt_target);
+		set_memory_ro(PAGE_MASK & ((uintptr_t)&plt->target), 1);
+		/* since plt target points to either the new trampoline
+		 * or dummy_tramp, even if another CPU reads the old plt
+		 * target value before fetching the bl instruction to plt,
+		 * it will be brought back by dummy_tramp, so no barrier is
+		 * required here.
+		 */
+	}
+
+	/* if the old target and the new target are both long jumps, no
+	 * patching is required
+	 */
+	if (old_insn == new_insn)
+		return 0;
+
+	mutex_lock(&text_mutex);
+	if (aarch64_insn_read(ip, &replaced)) {
+		ret = -EFAULT;
+		goto out;
+	}
+
+	if (replaced != old_insn) {
+		ret = -EFAULT;
+		goto out;
+	}
+
+	/* We call aarch64_insn_patch_text_nosync() to replace instruction
+	 * atomically, so no other CPUs will fetch a half-new and half-old
+	 * instruction. But there is chance that another CPU executes the
+	 * old instruction after the patching operation finishes (e.g.,
+	 * pipeline not flushed, or icache not synchronized yet).
+	 *
+	 * 1. when a new trampoline is attached, it is not a problem for
+	 *    different CPUs to jump to different trampolines temporarily.
+	 *
+	 * 2. when an old trampoline is freed, we should wait for all other
+	 *    CPUs to exit the trampoline and make sure the trampoline is no
+	 *    longer reachable, since bpf_tramp_image_put() function already
+	 *    uses percpu_ref and task-based rcu to do the sync, no need to call
+	 *    the sync version here, see bpf_tramp_image_put() for details.
+	 */
+	ret = aarch64_insn_patch_text_nosync(ip, new_insn);
+out:
+	mutex_unlock(&text_mutex);
+
+	return ret;
+}