LoongArch: Add BPF JIT support

BPF programs are normally handled by a BPF interpreter, add BPF JIT
support for LoongArch to allow the kernel to generate native code when
a program is loaded into the kernel. This will significantly speed-up
processing of BPF programs.

Co-developed-by: Youling Tang <tangyouling@loongson.cn>
Signed-off-by: Youling Tang <tangyouling@loongson.cn>
Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>

3 files changed, 1468 insertions, 0 deletions

diff --git a/arch/loongarch/net/Makefile b/arch/loongarch/net/Makefile
new file mode 100644
index 000000000000..1ec12a0c324a
--- /dev/null
+++ b/arch/loongarch/net/Makefile
@@ -0,0 +1,7 @@
+# SPDX-License-Identifier: GPL-2.0-only
+#
+# Makefile for arch/loongarch/net
+#
+# Copyright (C) 2022 Loongson Technology Corporation Limited
+#
+obj-$(CONFIG_BPF_JIT) += bpf_jit.o
diff --git a/arch/loongarch/net/bpf_jit.c b/arch/loongarch/net/bpf_jit.c
new file mode 100644
index 000000000000..43f0a98efe38
--- /dev/null
+++ b/arch/loongarch/net/bpf_jit.c
@@ -0,0 +1,1179 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * BPF JIT compiler for LoongArch
+ *
+ * Copyright (C) 2022 Loongson Technology Corporation Limited
+ */
+#include "bpf_jit.h"
+
+#define REG_TCC		LOONGARCH_GPR_A6
+#define TCC_SAVED	LOONGARCH_GPR_S5
+
+#define SAVE_RA		BIT(0)
+#define SAVE_TCC	BIT(1)
+
+static const int regmap[] = {
+	/* return value from in-kernel function, and exit value for eBPF program */
+	[BPF_REG_0] = LOONGARCH_GPR_A5,
+	/* arguments from eBPF program to in-kernel function */
+	[BPF_REG_1] = LOONGARCH_GPR_A0,
+	[BPF_REG_2] = LOONGARCH_GPR_A1,
+	[BPF_REG_3] = LOONGARCH_GPR_A2,
+	[BPF_REG_4] = LOONGARCH_GPR_A3,
+	[BPF_REG_5] = LOONGARCH_GPR_A4,
+	/* callee saved registers that in-kernel function will preserve */
+	[BPF_REG_6] = LOONGARCH_GPR_S0,
+	[BPF_REG_7] = LOONGARCH_GPR_S1,
+	[BPF_REG_8] = LOONGARCH_GPR_S2,
+	[BPF_REG_9] = LOONGARCH_GPR_S3,
+	/* read-only frame pointer to access stack */
+	[BPF_REG_FP] = LOONGARCH_GPR_S4,
+	/* temporary register for blinding constants */
+	[BPF_REG_AX] = LOONGARCH_GPR_T0,
+};
+
+static void mark_call(struct jit_ctx *ctx)
+{
+	ctx->flags |= SAVE_RA;
+}
+
+static void mark_tail_call(struct jit_ctx *ctx)
+{
+	ctx->flags |= SAVE_TCC;
+}
+
+static bool seen_call(struct jit_ctx *ctx)
+{
+	return (ctx->flags & SAVE_RA);
+}
+
+static bool seen_tail_call(struct jit_ctx *ctx)
+{
+	return (ctx->flags & SAVE_TCC);
+}
+
+static u8 tail_call_reg(struct jit_ctx *ctx)
+{
+	if (seen_call(ctx))
+		return TCC_SAVED;
+
+	return REG_TCC;
+}
+
+/*
+ * eBPF prog stack layout:
+ *
+ *                                        high
+ * original $sp ------------> +-------------------------+ <--LOONGARCH_GPR_FP
+ *                            |           $ra           |
+ *                            +-------------------------+
+ *                            |           $fp           |
+ *                            +-------------------------+
+ *                            |           $s0           |
+ *                            +-------------------------+
+ *                            |           $s1           |
+ *                            +-------------------------+
+ *                            |           $s2           |
+ *                            +-------------------------+
+ *                            |           $s3           |
+ *                            +-------------------------+
+ *                            |           $s4           |
+ *                            +-------------------------+
+ *                            |           $s5           |
+ *                            +-------------------------+ <--BPF_REG_FP
+ *                            |  prog->aux->stack_depth |
+ *                            |        (optional)       |
+ * current $sp -------------> +-------------------------+
+ *                                        low
+ */
+static void build_prologue(struct jit_ctx *ctx)
+{
+	int stack_adjust = 0, store_offset, bpf_stack_adjust;
+
+	bpf_stack_adjust = round_up(ctx->prog->aux->stack_depth, 16);
+
+	/* To store ra, fp, s0, s1, s2, s3, s4 and s5. */
+	stack_adjust += sizeof(long) * 8;
+
+	stack_adjust = round_up(stack_adjust, 16);
+	stack_adjust += bpf_stack_adjust;
+
+	/*
+	 * First instruction initializes the tail call count (TCC).
+	 * On tail call we skip this instruction, and the TCC is
+	 * passed in REG_TCC from the caller.
+	 */
+	emit_insn(ctx, addid, REG_TCC, LOONGARCH_GPR_ZERO, MAX_TAIL_CALL_CNT);
+
+	emit_insn(ctx, addid, LOONGARCH_GPR_SP, LOONGARCH_GPR_SP, -stack_adjust);
+
+	store_offset = stack_adjust - sizeof(long);
+	emit_insn(ctx, std, LOONGARCH_GPR_RA, LOONGARCH_GPR_SP, store_offset);
+
+	store_offset -= sizeof(long);
+	emit_insn(ctx, std, LOONGARCH_GPR_FP, LOONGARCH_GPR_SP, store_offset);
+
+	store_offset -= sizeof(long);
+	emit_insn(ctx, std, LOONGARCH_GPR_S0, LOONGARCH_GPR_SP, store_offset);
+
+	store_offset -= sizeof(long);
+	emit_insn(ctx, std, LOONGARCH_GPR_S1, LOONGARCH_GPR_SP, store_offset);
+
+	store_offset -= sizeof(long);
+	emit_insn(ctx, std, LOONGARCH_GPR_S2, LOONGARCH_GPR_SP, store_offset);
+
+	store_offset -= sizeof(long);
+	emit_insn(ctx, std, LOONGARCH_GPR_S3, LOONGARCH_GPR_SP, store_offset);
+
+	store_offset -= sizeof(long);
+	emit_insn(ctx, std, LOONGARCH_GPR_S4, LOONGARCH_GPR_SP, store_offset);
+
+	store_offset -= sizeof(long);
+	emit_insn(ctx, std, LOONGARCH_GPR_S5, LOONGARCH_GPR_SP, store_offset);
+
+	emit_insn(ctx, addid, LOONGARCH_GPR_FP, LOONGARCH_GPR_SP, stack_adjust);
+
+	if (bpf_stack_adjust)
+		emit_insn(ctx, addid, regmap[BPF_REG_FP], LOONGARCH_GPR_SP, bpf_stack_adjust);
+
+	/*
+	 * Program contains calls and tail calls, so REG_TCC need
+	 * to be saved across calls.
+	 */
+	if (seen_tail_call(ctx) && seen_call(ctx))
+		move_reg(ctx, TCC_SAVED, REG_TCC);
+
+	ctx->stack_size = stack_adjust;
+}
+
+static void __build_epilogue(struct jit_ctx *ctx, bool is_tail_call)
+{
+	int stack_adjust = ctx->stack_size;
+	int load_offset;
+
+	load_offset = stack_adjust - sizeof(long);
+	emit_insn(ctx, ldd, LOONGARCH_GPR_RA, LOONGARCH_GPR_SP, load_offset);
+
+	load_offset -= sizeof(long);
+	emit_insn(ctx, ldd, LOONGARCH_GPR_FP, LOONGARCH_GPR_SP, load_offset);
+
+	load_offset -= sizeof(long);
+	emit_insn(ctx, ldd, LOONGARCH_GPR_S0, LOONGARCH_GPR_SP, load_offset);
+
+	load_offset -= sizeof(long);
+	emit_insn(ctx, ldd, LOONGARCH_GPR_S1, LOONGARCH_GPR_SP, load_offset);
+
+	load_offset -= sizeof(long);
+	emit_insn(ctx, ldd, LOONGARCH_GPR_S2, LOONGARCH_GPR_SP, load_offset);
+
+	load_offset -= sizeof(long);
+	emit_insn(ctx, ldd, LOONGARCH_GPR_S3, LOONGARCH_GPR_SP, load_offset);
+
+	load_offset -= sizeof(long);
+	emit_insn(ctx, ldd, LOONGARCH_GPR_S4, LOONGARCH_GPR_SP, load_offset);
+
+	load_offset -= sizeof(long);
+	emit_insn(ctx, ldd, LOONGARCH_GPR_S5, LOONGARCH_GPR_SP, load_offset);
+
+	emit_insn(ctx, addid, LOONGARCH_GPR_SP, LOONGARCH_GPR_SP, stack_adjust);
+
+	if (!is_tail_call) {
+		/* Set return value */
+		move_reg(ctx, LOONGARCH_GPR_A0, regmap[BPF_REG_0]);
+		/* Return to the caller */
+		emit_insn(ctx, jirl, LOONGARCH_GPR_RA, LOONGARCH_GPR_ZERO, 0);
+	} else {
+		/*
+		 * Call the next bpf prog and skip the first instruction
+		 * of TCC initialization.
+		 */
+		emit_insn(ctx, jirl, LOONGARCH_GPR_T3, LOONGARCH_GPR_ZERO, 1);
+	}
+}
+
+static void build_epilogue(struct jit_ctx *ctx)
+{
+	__build_epilogue(ctx, false);
+}
+
+bool bpf_jit_supports_kfunc_call(void)
+{
+	return true;
+}
+
+/* initialized on the first pass of build_body() */
+static int out_offset = -1;
+static int emit_bpf_tail_call(struct jit_ctx *ctx)
+{
+	int off;
+	u8 tcc = tail_call_reg(ctx);
+	u8 a1 = LOONGARCH_GPR_A1;
+	u8 a2 = LOONGARCH_GPR_A2;
+	u8 t1 = LOONGARCH_GPR_T1;
+	u8 t2 = LOONGARCH_GPR_T2;
+	u8 t3 = LOONGARCH_GPR_T3;
+	const int idx0 = ctx->idx;
+
+#define cur_offset (ctx->idx - idx0)
+#define jmp_offset (out_offset - (cur_offset))
+
+	/*
+	 * a0: &ctx
+	 * a1: &array
+	 * a2: index
+	 *
+	 * if (index >= array->map.max_entries)
+	 *	 goto out;
+	 */
+	off = offsetof(struct bpf_array, map.max_entries);
+	emit_insn(ctx, ldwu, t1, a1, off);
+	/* bgeu $a2, $t1, jmp_offset */
+	if (emit_tailcall_jmp(ctx, BPF_JGE, a2, t1, jmp_offset) < 0)
+		goto toofar;
+
+	/*
+	 * if (--TCC < 0)
+	 *	 goto out;
+	 */
+	emit_insn(ctx, addid, REG_TCC, tcc, -1);
+	if (emit_tailcall_jmp(ctx, BPF_JSLT, REG_TCC, LOONGARCH_GPR_ZERO, jmp_offset) < 0)
+		goto toofar;
+
+	/*
+	 * prog = array->ptrs[index];
+	 * if (!prog)
+	 *	 goto out;
+	 */
+	emit_insn(ctx, alsld, t2, a2, a1, 2);
+	off = offsetof(struct bpf_array, ptrs);
+	emit_insn(ctx, ldd, t2, t2, off);
+	/* beq $t2, $zero, jmp_offset */
+	if (emit_tailcall_jmp(ctx, BPF_JEQ, t2, LOONGARCH_GPR_ZERO, jmp_offset) < 0)
+		goto toofar;
+
+	/* goto *(prog->bpf_func + 4); */
+	off = offsetof(struct bpf_prog, bpf_func);
+	emit_insn(ctx, ldd, t3, t2, off);
+	__build_epilogue(ctx, true);
+
+	/* 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;
+
+toofar:
+	pr_info_once("tail_call: jump too far\n");
+	return -1;
+#undef cur_offset
+#undef jmp_offset
+}
+
+static void emit_atomic(const struct bpf_insn *insn, struct jit_ctx *ctx)
+{
+	const u8 t1 = LOONGARCH_GPR_T1;
+	const u8 t2 = LOONGARCH_GPR_T2;
+	const u8 t3 = LOONGARCH_GPR_T3;
+	const u8 src = regmap[insn->src_reg];
+	const u8 dst = regmap[insn->dst_reg];
+	const s16 off = insn->off;
+	const s32 imm = insn->imm;
+	const bool isdw = BPF_SIZE(insn->code) == BPF_DW;
+
+	move_imm(ctx, t1, off, false);
+	emit_insn(ctx, addd, t1, dst, t1);
+	move_reg(ctx, t3, src);
+
+	switch (imm) {
+	/* lock *(size *)(dst + off) <op>= src */
+	case BPF_ADD:
+		if (isdw)
+			emit_insn(ctx, amaddd, t2, t1, src);
+		else
+			emit_insn(ctx, amaddw, t2, t1, src);
+		break;
+	case BPF_AND:
+		if (isdw)
+			emit_insn(ctx, amandd, t2, t1, src);
+		else
+			emit_insn(ctx, amandw, t2, t1, src);
+		break;
+	case BPF_OR:
+		if (isdw)
+			emit_insn(ctx, amord, t2, t1, src);
+		else
+			emit_insn(ctx, amorw, t2, t1, src);
+		break;
+	case BPF_XOR:
+		if (isdw)
+			emit_insn(ctx, amxord, t2, t1, src);
+		else
+			emit_insn(ctx, amxorw, t2, t1, src);
+		break;
+	/* src = atomic_fetch_<op>(dst + off, src) */
+	case BPF_ADD | BPF_FETCH:
+		if (isdw) {
+			emit_insn(ctx, amaddd, src, t1, t3);
+		} else {
+			emit_insn(ctx, amaddw, src, t1, t3);
+			emit_zext_32(ctx, src, true);
+		}
+		break;
+	case BPF_AND | BPF_FETCH:
+		if (isdw) {
+			emit_insn(ctx, amandd, src, t1, t3);
+		} else {
+			emit_insn(ctx, amandw, src, t1, t3);
+			emit_zext_32(ctx, src, true);
+		}
+		break;
+	case BPF_OR | BPF_FETCH:
+		if (isdw) {
+			emit_insn(ctx, amord, src, t1, t3);
+		} else {
+			emit_insn(ctx, amorw, src, t1, t3);
+			emit_zext_32(ctx, src, true);
+		}
+		break;
+	case BPF_XOR | BPF_FETCH:
+		if (isdw) {
+			emit_insn(ctx, amxord, src, t1, t3);
+		} else {
+			emit_insn(ctx, amxorw, src, t1, t3);
+			emit_zext_32(ctx, src, true);
+		}
+		break;
+	/* src = atomic_xchg(dst + off, src); */
+	case BPF_XCHG:
+		if (isdw) {
+			emit_insn(ctx, amswapd, src, t1, t3);
+		} else {
+			emit_insn(ctx, amswapw, src, t1, t3);
+			emit_zext_32(ctx, src, true);
+		}
+		break;
+	/* r0 = atomic_cmpxchg(dst + off, r0, src); */
+	case BPF_CMPXCHG:
+		u8 r0 = regmap[BPF_REG_0];
+
+		move_reg(ctx, t2, r0);
+		if (isdw) {
+			emit_insn(ctx, lld, r0, t1, 0);
+			emit_insn(ctx, bne, t2, r0, 4);
+			move_reg(ctx, t3, src);
+			emit_insn(ctx, scd, t3, t1, 0);
+			emit_insn(ctx, beq, t3, LOONGARCH_GPR_ZERO, -4);
+		} else {
+			emit_insn(ctx, llw, r0, t1, 0);
+			emit_zext_32(ctx, t2, true);
+			emit_zext_32(ctx, r0, true);
+			emit_insn(ctx, bne, t2, r0, 4);
+			move_reg(ctx, t3, src);
+			emit_insn(ctx, scw, t3, t1, 0);
+			emit_insn(ctx, beq, t3, LOONGARCH_GPR_ZERO, -6);
+			emit_zext_32(ctx, r0, true);
+		}
+		break;
+	}
+}
+
+static bool is_signed_bpf_cond(u8 cond)
+{
+	return cond == BPF_JSGT || cond == BPF_JSLT ||
+	       cond == BPF_JSGE || cond == BPF_JSLE;
+}
+
+static int build_insn(const struct bpf_insn *insn, struct jit_ctx *ctx, bool extra_pass)
+{
+	const bool is32 = BPF_CLASS(insn->code) == BPF_ALU ||
+			  BPF_CLASS(insn->code) == BPF_JMP32;
+	const u8 code = insn->code;
+	const u8 cond = BPF_OP(code);
+	const u8 t1 = LOONGARCH_GPR_T1;
+	const u8 t2 = LOONGARCH_GPR_T2;
+	const u8 src = regmap[insn->src_reg];
+	const u8 dst = regmap[insn->dst_reg];
+	const s16 off = insn->off;
+	const s32 imm = insn->imm;
+	int jmp_offset;
+	int i = insn - ctx->prog->insnsi;
+
+	switch (code) {
+	/* dst = src */
+	case BPF_ALU | BPF_MOV | BPF_X:
+	case BPF_ALU64 | BPF_MOV | BPF_X:
+		move_reg(ctx, dst, src);
+		emit_zext_32(ctx, dst, is32);
+		break;
+
+	/* dst = imm */
+	case BPF_ALU | BPF_MOV | BPF_K:
+	case BPF_ALU64 | BPF_MOV | BPF_K:
+		move_imm(ctx, dst, imm, is32);
+		break;
+
+	/* dst = dst + src */
+	case BPF_ALU | BPF_ADD | BPF_X:
+	case BPF_ALU64 | BPF_ADD | BPF_X:
+		emit_insn(ctx, addd, dst, dst, src);
+		emit_zext_32(ctx, dst, is32);
+		break;
+
+	/* dst = dst + imm */
+	case BPF_ALU | BPF_ADD | BPF_K:
+	case BPF_ALU64 | BPF_ADD | BPF_K:
+		if (is_signed_imm12(imm)) {
+			emit_insn(ctx, addid, dst, dst, imm);
+		} else {
+			move_imm(ctx, t1, imm, is32);
+			emit_insn(ctx, addd, dst, dst, t1);
+		}
+		emit_zext_32(ctx, dst, is32);
+		break;
+
+	/* dst = dst - src */
+	case BPF_ALU | BPF_SUB | BPF_X:
+	case BPF_ALU64 | BPF_SUB | BPF_X:
+		emit_insn(ctx, subd, dst, dst, src);
+		emit_zext_32(ctx, dst, is32);
+		break;
+
+	/* dst = dst - imm */
+	case BPF_ALU | BPF_SUB | BPF_K:
+	case BPF_ALU64 | BPF_SUB | BPF_K:
+		if (is_signed_imm12(-imm)) {
+			emit_insn(ctx, addid, dst, dst, -imm);
+		} else {
+			move_imm(ctx, t1, imm, is32);
+			emit_insn(ctx, subd, dst, dst, t1);
+		}
+		emit_zext_32(ctx, dst, is32);
+		break;
+
+	/* dst = dst * src */
+	case BPF_ALU | BPF_MUL | BPF_X:
+	case BPF_ALU64 | BPF_MUL | BPF_X:
+		emit_insn(ctx, muld, dst, dst, src);
+		emit_zext_32(ctx, dst, is32);
+		break;
+
+	/* dst = dst * imm */
+	case BPF_ALU | BPF_MUL | BPF_K:
+	case BPF_ALU64 | BPF_MUL | BPF_K:
+		move_imm(ctx, t1, imm, is32);
+		emit_insn(ctx, muld, dst, dst, t1);
+		emit_zext_32(ctx, dst, is32);
+		break;
+
+	/* dst = dst / src */
+	case BPF_ALU | BPF_DIV | BPF_X:
+	case BPF_ALU64 | BPF_DIV | BPF_X:
+		emit_zext_32(ctx, dst, is32);
+		move_reg(ctx, t1, src);
+		emit_zext_32(ctx, t1, is32);
+		emit_insn(ctx, divdu, dst, dst, t1);
+		emit_zext_32(ctx, dst, is32);
+		break;
+
+	/* dst = dst / imm */
+	case BPF_ALU | BPF_DIV | BPF_K:
+	case BPF_ALU64 | BPF_DIV | BPF_K:
+		move_imm(ctx, t1, imm, is32);
+		emit_zext_32(ctx, dst, is32);
+		emit_insn(ctx, divdu, dst, dst, t1);
+		emit_zext_32(ctx, dst, is32);
+		break;
+
+	/* dst = dst % src */
+	case BPF_ALU | BPF_MOD | BPF_X:
+	case BPF_ALU64 | BPF_MOD | BPF_X:
+		emit_zext_32(ctx, dst, is32);
+		move_reg(ctx, t1, src);
+		emit_zext_32(ctx, t1, is32);
+		emit_insn(ctx, moddu, dst, dst, t1);
+		emit_zext_32(ctx, dst, is32);
+		break;
+
+	/* dst = dst % imm */
+	case BPF_ALU | BPF_MOD | BPF_K:
+	case BPF_ALU64 | BPF_MOD | BPF_K:
+		move_imm(ctx, t1, imm, is32);
+		emit_zext_32(ctx, dst, is32);
+		emit_insn(ctx, moddu, dst, dst, t1);
+		emit_zext_32(ctx, dst, is32);
+		break;
+
+	/* dst = -dst */
+	case BPF_ALU | BPF_NEG:
+	case BPF_ALU64 | BPF_NEG:
+		move_imm(ctx, t1, imm, is32);
+		emit_insn(ctx, subd, dst, LOONGARCH_GPR_ZERO, dst);
+		emit_zext_32(ctx, dst, is32);
+		break;
+
+	/* dst = dst & src */
+	case BPF_ALU | BPF_AND | BPF_X:
+	case BPF_ALU64 | BPF_AND | BPF_X:
+		emit_insn(ctx, and, dst, dst, src);
+		emit_zext_32(ctx, dst, is32);
+		break;
+
+	/* dst = dst & imm */
+	case BPF_ALU | BPF_AND | BPF_K:
+	case BPF_ALU64 | BPF_AND | BPF_K:
+		if (is_unsigned_imm12(imm)) {
+			emit_insn(ctx, andi, dst, dst, imm);
+		} else {
+			move_imm(ctx, t1, imm, is32);
+			emit_insn(ctx, and, dst, dst, t1);
+		}
+		emit_zext_32(ctx, dst, is32);
+		break;
+
+	/* dst = dst | src */
+	case BPF_ALU | BPF_OR | BPF_X:
+	case BPF_ALU64 | BPF_OR | BPF_X:
+		emit_insn(ctx, or, dst, dst, src);
+		emit_zext_32(ctx, dst, is32);
+		break;
+
+	/* dst = dst | imm */
+	case BPF_ALU | BPF_OR | BPF_K:
+	case BPF_ALU64 | BPF_OR | BPF_K:
+		if (is_unsigned_imm12(imm)) {
+			emit_insn(ctx, ori, dst, dst, imm);
+		} else {
+			move_imm(ctx, t1, imm, is32);
+			emit_insn(ctx, or, dst, dst, t1);
+		}
+		emit_zext_32(ctx, dst, is32);
+		break;
+
+	/* dst = dst ^ src */
+	case BPF_ALU | BPF_XOR | BPF_X:
+	case BPF_ALU64 | BPF_XOR | BPF_X:
+		emit_insn(ctx, xor, dst, dst, src);
+		emit_zext_32(ctx, dst, is32);
+		break;
+
+	/* dst = dst ^ imm */
+	case BPF_ALU | BPF_XOR | BPF_K:
+	case BPF_ALU64 | BPF_XOR | BPF_K:
+		if (is_unsigned_imm12(imm)) {
+			emit_insn(ctx, xori, dst, dst, imm);
+		} else {
+			move_imm(ctx, t1, imm, is32);
+			emit_insn(ctx, xor, dst, dst, t1);
+		}
+		emit_zext_32(ctx, dst, is32);
+		break;
+
+	/* dst = dst << src (logical) */
+	case BPF_ALU | BPF_LSH | BPF_X:
+		emit_insn(ctx, sllw, dst, dst, src);
+		emit_zext_32(ctx, dst, is32);
+		break;
+
+	case BPF_ALU64 | BPF_LSH | BPF_X:
+		emit_insn(ctx, slld, dst, dst, src);
+		break;
+
+	/* dst = dst << imm (logical) */
+	case BPF_ALU | BPF_LSH | BPF_K:
+		emit_insn(ctx, slliw, dst, dst, imm);
+		emit_zext_32(ctx, dst, is32);
+		break;
+
+	case BPF_ALU64 | BPF_LSH | BPF_K:
+		emit_insn(ctx, sllid, dst, dst, imm);
+		break;
+
+	/* dst = dst >> src (logical) */
+	case BPF_ALU | BPF_RSH | BPF_X:
+		emit_insn(ctx, srlw, dst, dst, src);
+		emit_zext_32(ctx, dst, is32);
+		break;
+
+	case BPF_ALU64 | BPF_RSH | BPF_X:
+		emit_insn(ctx, srld, dst, dst, src);
+		break;
+
+	/* dst = dst >> imm (logical) */
+	case BPF_ALU | BPF_RSH | BPF_K:
+		emit_insn(ctx, srliw, dst, dst, imm);
+		emit_zext_32(ctx, dst, is32);
+		break;
+
+	case BPF_ALU64 | BPF_RSH | BPF_K:
+		emit_insn(ctx, srlid, dst, dst, imm);
+		break;
+
+	/* dst = dst >> src (arithmetic) */
+	case BPF_ALU | BPF_ARSH | BPF_X:
+		emit_insn(ctx, sraw, dst, dst, src);
+		emit_zext_32(ctx, dst, is32);
+		break;
+
+	case BPF_ALU64 | BPF_ARSH | BPF_X:
+		emit_insn(ctx, srad, dst, dst, src);
+		break;
+
+	/* dst = dst >> imm (arithmetic) */
+	case BPF_ALU | BPF_ARSH | BPF_K:
+		emit_insn(ctx, sraiw, dst, dst, imm);
+		emit_zext_32(ctx, dst, is32);
+		break;
+
+	case BPF_ALU64 | BPF_ARSH | BPF_K:
+		emit_insn(ctx, sraid, dst, dst, imm);
+		break;
+
+	/* dst = BSWAP##imm(dst) */
+	case BPF_ALU | BPF_END | BPF_FROM_LE:
+		switch (imm) {
+		case 16:
+			/* zero-extend 16 bits into 64 bits */
+			emit_insn(ctx, bstrpickd, dst, dst, 15, 0);
+			break;
+		case 32:
+			/* zero-extend 32 bits into 64 bits */
+			emit_zext_32(ctx, dst, is32);
+			break;
+		case 64:
+			/* do nothing */
+			break;
+		}
+		break;
+
+	case BPF_ALU | BPF_END | BPF_FROM_BE:
+		switch (imm) {
+		case 16:
+			emit_insn(ctx, revb2h, dst, dst);
+			/* zero-extend 16 bits into 64 bits */
+			emit_insn(ctx, bstrpickd, dst, dst, 15, 0);
+			break;
+		case 32:
+			emit_insn(ctx, revb2w, dst, dst);
+			/* zero-extend 32 bits into 64 bits */
+			emit_zext_32(ctx, dst, is32);
+			break;
+		case 64:
+			emit_insn(ctx, revbd, dst, dst);
+			break;
+		}
+		break;
+
+	/* PC += off if dst cond src */
+	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_JGE | BPF_X:
+	case BPF_JMP | BPF_JLT | BPF_X:
+	case BPF_JMP | BPF_JLE | BPF_X:
+	case BPF_JMP | BPF_JSGT | BPF_X:
+	case BPF_JMP | BPF_JSGE | BPF_X:
+	case BPF_JMP | BPF_JSLT | 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_JGE | BPF_X:
+	case BPF_JMP32 | BPF_JLT | BPF_X:
+	case BPF_JMP32 | BPF_JLE | BPF_X:
+	case BPF_JMP32 | BPF_JSGT | BPF_X:
+	case BPF_JMP32 | BPF_JSGE | BPF_X:
+	case BPF_JMP32 | BPF_JSLT | BPF_X:
+	case BPF_JMP32 | BPF_JSLE | BPF_X:
+		jmp_offset = bpf2la_offset(i, off, ctx);
+		move_reg(ctx, t1, dst);
+		move_reg(ctx, t2, src);
+		if (is_signed_bpf_cond(BPF_OP(code))) {
+			emit_sext_32(ctx, t1, is32);
+			emit_sext_32(ctx, t2, is32);
+		} else {
+			emit_zext_32(ctx, t1, is32);
+			emit_zext_32(ctx, t2, is32);
+		}
+		if (emit_cond_jmp(ctx, cond, t1, t2, jmp_offset) < 0)
+			goto toofar;
+		break;
+
+	/* PC += off if dst cond imm */
+	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_JGE | BPF_K:
+	case BPF_JMP | BPF_JLT | BPF_K:
+	case BPF_JMP | BPF_JLE | BPF_K:
+	case BPF_JMP | BPF_JSGT | BPF_K:
+	case BPF_JMP | BPF_JSGE | BPF_K:
+	case BPF_JMP | BPF_JSLT | 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_JGE | BPF_K:
+	case BPF_JMP32 | BPF_JLT | BPF_K:
+	case BPF_JMP32 | BPF_JLE | BPF_K:
+	case BPF_JMP32 | BPF_JSGT | BPF_K:
+	case BPF_JMP32 | BPF_JSGE | BPF_K:
+	case BPF_JMP32 | BPF_JSLT | BPF_K:
+	case BPF_JMP32 | BPF_JSLE | BPF_K:
+		u8 t7 = -1;
+		jmp_offset = bpf2la_offset(i, off, ctx);
+		if (imm) {
+			move_imm(ctx, t1, imm, false);
+			t7 = t1;
+		} else {
+			/* If imm is 0, simply use zero register. */
+			t7 = LOONGARCH_GPR_ZERO;
+		}
+		move_reg(ctx, t2, dst);
+		if (is_signed_bpf_cond(BPF_OP(code))) {
+			emit_sext_32(ctx, t7, is32);
+			emit_sext_32(ctx, t2, is32);
+		} else {
+			emit_zext_32(ctx, t7, is32);
+			emit_zext_32(ctx, t2, is32);
+		}
+		if (emit_cond_jmp(ctx, cond, t2, t7, jmp_offset) < 0)
+			goto toofar;
+		break;
+
+	/* PC += off if dst & src */
+	case BPF_JMP | BPF_JSET | BPF_X:
+	case BPF_JMP32 | BPF_JSET | BPF_X:
+		jmp_offset = bpf2la_offset(i, off, ctx);
+		emit_insn(ctx, and, t1, dst, src);
+		emit_zext_32(ctx, t1, is32);
+		if (emit_cond_jmp(ctx, cond, t1, LOONGARCH_GPR_ZERO, jmp_offset) < 0)
+			goto toofar;
+		break;
+
+	/* PC += off if dst & imm */
+	case BPF_JMP | BPF_JSET | BPF_K:
+	case BPF_JMP32 | BPF_JSET | BPF_K:
+		jmp_offset = bpf2la_offset(i, off, ctx);
+		move_imm(ctx, t1, imm, is32);
+		emit_insn(ctx, and, t1, dst, t1);
+		emit_zext_32(ctx, t1, is32);
+		if (emit_cond_jmp(ctx, cond, t1, LOONGARCH_GPR_ZERO, jmp_offset) < 0)
+			goto toofar;
+		break;
+
+	/* PC += off */
+	case BPF_JMP | BPF_JA:
+		jmp_offset = bpf2la_offset(i, off, ctx);
+		if (emit_uncond_jmp(ctx, jmp_offset) < 0)
+			goto toofar;
+		break;
+
+	/* function call */
+	case BPF_JMP | BPF_CALL:
+		int ret;
+		u64 func_addr;
+		bool func_addr_fixed;
+
+		mark_call(ctx);
+		ret = bpf_jit_get_func_addr(ctx->prog, insn, extra_pass,
+					    &func_addr, &func_addr_fixed);
+		if (ret < 0)
+			return ret;
+
+		move_imm(ctx, t1, func_addr, is32);
+		emit_insn(ctx, jirl, t1, LOONGARCH_GPR_RA, 0);
+		move_reg(ctx, regmap[BPF_REG_0], LOONGARCH_GPR_A0);
+		break;
+
+	/* tail call */
+	case BPF_JMP | BPF_TAIL_CALL:
+		mark_tail_call(ctx);
+		if (emit_bpf_tail_call(ctx) < 0)
+			return -EINVAL;
+		break;
+
+	/* function return */
+	case BPF_JMP | BPF_EXIT:
+		emit_sext_32(ctx, regmap[BPF_REG_0], true);
+
+		if (i == ctx->prog->len - 1)
+			break;
+
+		jmp_offset = epilogue_offset(ctx);
+		if (emit_uncond_jmp(ctx, jmp_offset) < 0)
+			goto toofar;
+		break;
+
+	/* dst = imm64 */
+	case BPF_LD | BPF_IMM | BPF_DW:
+		u64 imm64 = (u64)(insn + 1)->imm << 32 | (u32)insn->imm;
+
+		move_imm(ctx, dst, imm64, is32);
+		return 1;
+
+	/* dst = *(size *)(src + off) */
+	case BPF_LDX | BPF_MEM | BPF_B:
+	case BPF_LDX | BPF_MEM | BPF_H:
+	case BPF_LDX | BPF_MEM | BPF_W:
+	case BPF_LDX | BPF_MEM | BPF_DW:
+		switch (BPF_SIZE(code)) {
+		case BPF_B:
+			if (is_signed_imm12(off)) {
+				emit_insn(ctx, ldbu, dst, src, off);
+			} else {
+				move_imm(ctx, t1, off, is32);
+				emit_insn(ctx, ldxbu, dst, src, t1);
+			}
+			break;
+		case BPF_H:
+			if (is_signed_imm12(off)) {
+				emit_insn(ctx, ldhu, dst, src, off);
+			} else {
+				move_imm(ctx, t1, off, is32);
+				emit_insn(ctx, ldxhu, dst, src, t1);
+			}
+			break;
+		case BPF_W:
+			if (is_signed_imm12(off)) {
+				emit_insn(ctx, ldwu, dst, src, off);
+			} else if (is_signed_imm14(off)) {
+				emit_insn(ctx, ldptrw, dst, src, off);
+			} else {
+				move_imm(ctx, t1, off, is32);
+				emit_insn(ctx, ldxwu, dst, src, t1);
+			}
+			break;
+		case BPF_DW:
+			if (is_signed_imm12(off)) {
+				emit_insn(ctx, ldd, dst, src, off);
+			} else if (is_signed_imm14(off)) {
+				emit_insn(ctx, ldptrd, dst, src, off);
+			} else {
+				move_imm(ctx, t1, off, is32);
+				emit_insn(ctx, ldxd, dst, src, t1);
+			}
+			break;
+		}
+		break;
+
+	/* *(size *)(dst + off) = imm */
+	case BPF_ST | BPF_MEM | BPF_B:
+	case BPF_ST | BPF_MEM | BPF_H:
+	case BPF_ST | BPF_MEM | BPF_W:
+	case BPF_ST | BPF_MEM | BPF_DW:
+		switch (BPF_SIZE(code)) {
+		case BPF_B:
+			move_imm(ctx, t1, imm, is32);
+			if (is_signed_imm12(off)) {
+				emit_insn(ctx, stb, t1, dst, off);
+			} else {
+				move_imm(ctx, t2, off, is32);
+				emit_insn(ctx, stxb, t1, dst, t2);
+			}
+			break;
+		case BPF_H:
+			move_imm(ctx, t1, imm, is32);
+			if (is_signed_imm12(off)) {
+				emit_insn(ctx, sth, t1, dst, off);
+			} else {
+				move_imm(ctx, t2, off, is32);
+				emit_insn(ctx, stxh, t1, dst, t2);
+			}
+			break;
+		case BPF_W:
+			move_imm(ctx, t1, imm, is32);
+			if (is_signed_imm12(off)) {
+				emit_insn(ctx, stw, t1, dst, off);
+			} else if (is_signed_imm14(off)) {
+				emit_insn(ctx, stptrw, t1, dst, off);
+			} else {
+				move_imm(ctx, t2, off, is32);
+				emit_insn(ctx, stxw, t1, dst, t2);
+			}
+			break;
+		case BPF_DW:
+			move_imm(ctx, t1, imm, is32);
+			if (is_signed_imm12(off)) {
+				emit_insn(ctx, std, t1, dst, off);
+			} else if (is_signed_imm14(off)) {
+				emit_insn(ctx, stptrd, t1, dst, off);
+			} else {
+				move_imm(ctx, t2, off, is32);
+				emit_insn(ctx, stxd, t1, dst, t2);
+			}
+			break;
+		}
+		break;
+
+	/* *(size *)(dst + off) = src */
+	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:
+		switch (BPF_SIZE(code)) {
+		case BPF_B:
+			if (is_signed_imm12(off)) {
+				emit_insn(ctx, stb, src, dst, off);
+			} else {
+				move_imm(ctx, t1, off, is32);
+				emit_insn(ctx, stxb, src, dst, t1);
+			}
+			break;
+		case BPF_H:
+			if (is_signed_imm12(off)) {
+				emit_insn(ctx, sth, src, dst, off);
+			} else {
+				move_imm(ctx, t1, off, is32);
+				emit_insn(ctx, stxh, src, dst, t1);
+			}
+			break;
+		case BPF_W:
+			if (is_signed_imm12(off)) {
+				emit_insn(ctx, stw, src, dst, off);
+			} else if (is_signed_imm14(off)) {
+				emit_insn(ctx, stptrw, src, dst, off);
+			} else {
+				move_imm(ctx, t1, off, is32);
+				emit_insn(ctx, stxw, src, dst, t1);
+			}
+			break;
+		case BPF_DW:
+			if (is_signed_imm12(off)) {
+				emit_insn(ctx, std, src, dst, off);
+			} else if (is_signed_imm14(off)) {
+				emit_insn(ctx, stptrd, src, dst, off);
+			} else {
+				move_imm(ctx, t1, off, is32);
+				emit_insn(ctx, stxd, src, dst, t1);
+			}
+			break;
+		}
+		break;
+
+	case BPF_STX | BPF_ATOMIC | BPF_W:
+	case BPF_STX | BPF_ATOMIC | BPF_DW:
+		emit_atomic(insn, ctx);
+		break;
+
+	default:
+		pr_err("bpf_jit: unknown opcode %02x\n", code);
+		return -EINVAL;
+	}
+
+	return 0;
+
+toofar:
+	pr_info_once("bpf_jit: opcode %02x, jump too far\n", code);
+	return -E2BIG;
+}
+
+static int build_body(struct jit_ctx *ctx, bool extra_pass)
+{
+	int i;
+	const struct bpf_prog *prog = ctx->prog;
+
+	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;
+	}
+
+	if (ctx->image == NULL)
+		ctx->offset[i] = ctx->idx;
+
+	return 0;
+}
+
+/* Fill space with break instructions */
+static void jit_fill_hole(void *area, unsigned int size)
+{
+	u32 *ptr;
+
+	/* We are guaranteed to have aligned memory */
+	for (ptr = area; size >= sizeof(u32); size -= sizeof(u32))
+		*ptr++ = INSN_BREAK;
+}
+
+static int validate_code(struct jit_ctx *ctx)
+{
+	int i;
+	union loongarch_instruction insn;
+
+	for (i = 0; i < ctx->idx; i++) {
+		insn = ctx->image[i];
+		/* Check INSN_BREAK */
+		if (insn.word == INSN_BREAK)
+			return -1;
+	}
+
+	return 0;
+}
+
+struct bpf_prog *bpf_int_jit_compile(struct bpf_prog *prog)
+{
+	bool tmp_blinded = false, extra_pass = false;
+	u8 *image_ptr;
+	int image_size;
+	struct jit_ctx ctx;
+	struct jit_data *jit_data;
+	struct bpf_binary_header *header;
+	struct bpf_prog *tmp, *orig_prog = prog;
+
+	/*
+	 * If BPF JIT was not enabled then we must fall back to
+	 * the interpreter.
+	 */
+	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. Otherwise, we save
+	 * the new JITed code.
+	 */
+	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;
+		image_size = sizeof(u32) * ctx.idx;
+		goto skip_init_ctx;
+	}
+
+	memset(&ctx, 0, sizeof(ctx));
+	ctx.prog = prog;
+
+	ctx.offset = kvcalloc(prog->len + 1, sizeof(u32), GFP_KERNEL);
+	if (ctx.offset == NULL) {
+		prog = orig_prog;
+		goto out_offset;
+	}
+
+	/* 1. Initial fake pass to compute ctx->idx and set ctx->flags */
+	build_prologue(&ctx);
+	if (build_body(&ctx, extra_pass)) {
+		prog = orig_prog;
+		goto out_offset;
+	}
+	ctx.epilogue_offset = ctx.idx;
+	build_epilogue(&ctx);
+
+	/* Now we know the actual image size.
+	 * As each LoongArch instruction is of length 32bit,
+	 * we are translating number of JITed intructions into
+	 * the size required to store these JITed code.
+	 */
+	image_size = sizeof(u32) * ctx.idx;
+	/* Now we know the size of the structure to make */
+	header = bpf_jit_binary_alloc(image_size, &image_ptr,
+				      sizeof(u32), jit_fill_hole);
+	if (header == NULL) {
+		prog = orig_prog;
+		goto out_offset;
+	}
+
+	/* 2. Now, the actual pass to generate final JIT code */
+	ctx.image = (union loongarch_instruction *)image_ptr;
+
+skip_init_ctx:
+	ctx.idx = 0;
+
+	build_prologue(&ctx);
+	if (build_body(&ctx, extra_pass)) {
+		bpf_jit_binary_free(header);
+		prog = orig_prog;
+		goto out_offset;
+	}
+	build_epilogue(&ctx);
+
+	/* 3. Extra pass to validate JITed code */
+	if (validate_code(&ctx)) {
+		bpf_jit_binary_free(header);
+		prog = orig_prog;
+		goto out_offset;
+	}
+
+	/* And we're done */
+	if (bpf_jit_enable > 1)
+		bpf_jit_dump(prog->len, image_size, 2, ctx.image);
+
+	/* Update the icache */
+	flush_icache_range((unsigned long)header, (unsigned long)(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_offset;
+		}
+		bpf_jit_binary_lock_ro(header);
+	} else {
+		jit_data->ctx = ctx;
+		jit_data->image = image_ptr;
+		jit_data->header = header;
+	}
+	prog->jited = 1;
+	prog->jited_len = image_size;
+	prog->bpf_func = (void *)ctx.image;
+
+	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] *= LOONGARCH_INSN_SIZE;
+		bpf_prog_fill_jited_linfo(prog, ctx.offset + 1);
+
+out_offset:
+		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);
+
+	out_offset = -1;
+
+	return prog;
+}
diff --git a/arch/loongarch/net/bpf_jit.h b/arch/loongarch/net/bpf_jit.h
new file mode 100644
index 000000000000..e665ddb0aeb8
--- /dev/null
+++ b/arch/loongarch/net/bpf_jit.h
@@ -0,0 +1,282 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * BPF JIT compiler for LoongArch
+ *
+ * Copyright (C) 2022 Loongson Technology Corporation Limited
+ */
+#include <linux/bpf.h>
+#include <linux/filter.h>
+#include <asm/cacheflush.h>
+#include <asm/inst.h>
+
+struct jit_ctx {
+	const struct bpf_prog *prog;
+	unsigned int idx;
+	unsigned int flags;
+	unsigned int epilogue_offset;
+	u32 *offset;
+	union loongarch_instruction *image;
+	u32 stack_size;
+};
+
+struct jit_data {
+	struct bpf_binary_header *header;
+	u8 *image;
+	struct jit_ctx ctx;
+};
+
+#define emit_insn(ctx, func, ...)						\
+do {										\
+	if (ctx->image != NULL) {						\
+		union loongarch_instruction *insn = &ctx->image[ctx->idx];	\
+		emit_##func(insn, ##__VA_ARGS__);				\
+	}									\
+	ctx->idx++;								\
+} while (0)
+
+#define is_signed_imm12(val)	signed_imm_check(val, 12)
+#define is_signed_imm14(val)	signed_imm_check(val, 14)
+#define is_signed_imm16(val)	signed_imm_check(val, 16)
+#define is_signed_imm26(val)	signed_imm_check(val, 26)
+#define is_signed_imm32(val)	signed_imm_check(val, 32)
+#define is_signed_imm52(val)	signed_imm_check(val, 52)
+#define is_unsigned_imm12(val)	unsigned_imm_check(val, 12)
+
+static inline int bpf2la_offset(int bpf_insn, int off, const struct jit_ctx *ctx)
+{
+	/* BPF JMP offset is relative to the next instruction */
+	bpf_insn++;
+	/*
+	 * Whereas LoongArch 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 inline int epilogue_offset(const struct jit_ctx *ctx)
+{
+	int from = ctx->idx;
+	int to = ctx->epilogue_offset;
+
+	return (to - from);
+}
+
+/* Zero-extend 32 bits into 64 bits */
+static inline void emit_zext_32(struct jit_ctx *ctx, enum loongarch_gpr reg, bool is32)
+{
+	if (!is32)
+		return;
+
+	emit_insn(ctx, lu32id, reg, 0);
+}
+
+/* Signed-extend 32 bits into 64 bits */
+static inline void emit_sext_32(struct jit_ctx *ctx, enum loongarch_gpr reg, bool is32)
+{
+	if (!is32)
+		return;
+
+	emit_insn(ctx, addiw, reg, reg, 0);
+}
+
+static inline void move_imm(struct jit_ctx *ctx, enum loongarch_gpr rd, long imm, bool is32)
+{
+	long imm_11_0, imm_31_12, imm_51_32, imm_63_52, imm_51_0, imm_51_31;
+
+	/* or rd, $zero, $zero */
+	if (imm == 0) {
+		emit_insn(ctx, or, rd, LOONGARCH_GPR_ZERO, LOONGARCH_GPR_ZERO);
+		return;
+	}
+
+	/* addiw rd, $zero, imm_11_0 */
+	if (is_signed_imm12(imm)) {
+		emit_insn(ctx, addiw, rd, LOONGARCH_GPR_ZERO, imm);
+		goto zext;
+	}
+
+	/* ori rd, $zero, imm_11_0 */
+	if (is_unsigned_imm12(imm)) {
+		emit_insn(ctx, ori, rd, LOONGARCH_GPR_ZERO, imm);
+		goto zext;
+	}
+
+	/* lu52id rd, $zero, imm_63_52 */
+	imm_63_52 = (imm >> 52) & 0xfff;
+	imm_51_0 = imm & 0xfffffffffffff;
+	if (imm_63_52 != 0 && imm_51_0 == 0) {
+		emit_insn(ctx, lu52id, rd, LOONGARCH_GPR_ZERO, imm_63_52);
+		return;
+	}
+
+	/* lu12iw rd, imm_31_12 */
+	imm_31_12 = (imm >> 12) & 0xfffff;
+	emit_insn(ctx, lu12iw, rd, imm_31_12);
+
+	/* ori rd, rd, imm_11_0 */
+	imm_11_0 = imm & 0xfff;
+	if (imm_11_0 != 0)
+		emit_insn(ctx, ori, rd, rd, imm_11_0);
+
+	if (!is_signed_imm32(imm)) {
+		if (imm_51_0 != 0) {
+			/*
+			 * If bit[51:31] is all 0 or all 1,
+			 * it means bit[51:32] is sign extended by lu12iw,
+			 * no need to call lu32id to do a new filled operation.
+			 */
+			imm_51_31 = (imm >> 31) & 0x1fffff;
+			if (imm_51_31 != 0 || imm_51_31 != 0x1fffff) {
+				/* lu32id rd, imm_51_32 */
+				imm_51_32 = (imm >> 32) & 0xfffff;
+				emit_insn(ctx, lu32id, rd, imm_51_32);
+			}
+		}
+
+		/* lu52id rd, rd, imm_63_52 */
+		if (!is_signed_imm52(imm))
+			emit_insn(ctx, lu52id, rd, rd, imm_63_52);
+	}
+
+zext:
+	emit_zext_32(ctx, rd, is32);
+}
+
+static inline void move_reg(struct jit_ctx *ctx, enum loongarch_gpr rd,
+			    enum loongarch_gpr rj)
+{
+	emit_insn(ctx, or, rd, rj, LOONGARCH_GPR_ZERO);
+}
+
+static inline int invert_jmp_cond(u8 cond)
+{
+	switch (cond) {
+	case BPF_JEQ:
+		return BPF_JNE;
+	case BPF_JNE:
+	case BPF_JSET:
+		return BPF_JEQ;
+	case BPF_JGT:
+		return BPF_JLE;
+	case BPF_JGE:
+		return BPF_JLT;
+	case BPF_JLT:
+		return BPF_JGE;
+	case BPF_JLE:
+		return BPF_JGT;
+	case BPF_JSGT:
+		return BPF_JSLE;
+	case BPF_JSGE:
+		return BPF_JSLT;
+	case BPF_JSLT:
+		return BPF_JSGE;
+	case BPF_JSLE:
+		return BPF_JSGT;
+	}
+	return -1;
+}
+
+static inline void cond_jmp_offset(struct jit_ctx *ctx, u8 cond, enum loongarch_gpr rj,
+				   enum loongarch_gpr rd, int jmp_offset)
+{
+	switch (cond) {
+	case BPF_JEQ:
+		/* PC += jmp_offset if rj == rd */
+		emit_insn(ctx, beq, rj, rd, jmp_offset);
+		return;
+	case BPF_JNE:
+	case BPF_JSET:
+		/* PC += jmp_offset if rj != rd */
+		emit_insn(ctx, bne, rj, rd, jmp_offset);
+		return;
+	case BPF_JGT:
+		/* PC += jmp_offset if rj > rd (unsigned) */
+		emit_insn(ctx, bltu, rd, rj, jmp_offset);
+		return;
+	case BPF_JLT:
+		/* PC += jmp_offset if rj < rd (unsigned) */
+		emit_insn(ctx, bltu, rj, rd, jmp_offset);
+		return;
+	case BPF_JGE:
+		/* PC += jmp_offset if rj >= rd (unsigned) */
+		emit_insn(ctx, bgeu, rj, rd, jmp_offset);
+		return;
+	case BPF_JLE:
+		/* PC += jmp_offset if rj <= rd (unsigned) */
+		emit_insn(ctx, bgeu, rd, rj, jmp_offset);
+		return;
+	case BPF_JSGT:
+		/* PC += jmp_offset if rj > rd (signed) */
+		emit_insn(ctx, blt, rd, rj, jmp_offset);
+		return;
+	case BPF_JSLT:
+		/* PC += jmp_offset if rj < rd (signed) */
+		emit_insn(ctx, blt, rj, rd, jmp_offset);
+		return;
+	case BPF_JSGE:
+		/* PC += jmp_offset if rj >= rd (signed) */
+		emit_insn(ctx, bge, rj, rd, jmp_offset);
+		return;
+	case BPF_JSLE:
+		/* PC += jmp_offset if rj <= rd (signed) */
+		emit_insn(ctx, bge, rd, rj, jmp_offset);
+		return;
+	}
+}
+
+static inline void cond_jmp_offs26(struct jit_ctx *ctx, u8 cond, enum loongarch_gpr rj,
+				   enum loongarch_gpr rd, int jmp_offset)
+{
+	cond = invert_jmp_cond(cond);
+	cond_jmp_offset(ctx, cond, rj, rd, 2);
+	emit_insn(ctx, b, jmp_offset);
+}
+
+static inline void uncond_jmp_offs26(struct jit_ctx *ctx, int jmp_offset)
+{
+	emit_insn(ctx, b, jmp_offset);
+}
+
+static inline int emit_cond_jmp(struct jit_ctx *ctx, u8 cond, enum loongarch_gpr rj,
+				enum loongarch_gpr rd, int jmp_offset)
+{
+	/*
+	 * A large PC-relative jump offset may overflow the immediate field of
+	 * the native conditional branch instruction, triggering a conversion
+	 * to use an absolute jump instead, this jump sequence is particularly
+	 * nasty. For now, use cond_jmp_offs26() directly to keep it simple.
+	 * In the future, maybe we can add support for far branching, the branch
+	 * relaxation requires more than two passes to converge, the code seems
+	 * too complex to understand, not quite sure whether it is necessary and
+	 * worth the extra pain. Anyway, just leave it as it is to enhance code
+	 * readability now.
+	 */
+	if (is_signed_imm26(jmp_offset)) {
+		cond_jmp_offs26(ctx, cond, rj, rd, jmp_offset);
+		return 0;
+	}
+
+	return -EINVAL;
+}
+
+static inline int emit_uncond_jmp(struct jit_ctx *ctx, int jmp_offset)
+{
+	if (is_signed_imm26(jmp_offset)) {
+		uncond_jmp_offs26(ctx, jmp_offset);
+		return 0;
+	}
+
+	return -EINVAL;
+}
+
+static inline int emit_tailcall_jmp(struct jit_ctx *ctx, u8 cond, enum loongarch_gpr rj,
+				    enum loongarch_gpr rd, int jmp_offset)
+{
+	if (is_signed_imm16(jmp_offset)) {
+		cond_jmp_offset(ctx, cond, rj, rd, jmp_offset);
+		return 0;
+	}
+
+	return -EINVAL;
+}