LoongArch: Add BPF JIT support
authorTiezhu Yang <yangtiezhu@loongson.cn>
Wed, 12 Oct 2022 08:36:20 +0000 (16:36 +0800)
committerHuacai Chen <chenhuacai@loongson.cn>
Wed, 12 Oct 2022 08:36:20 +0000 (16:36 +0800)
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>
arch/loongarch/Kbuild
arch/loongarch/Kconfig
arch/loongarch/include/asm/inst.h
arch/loongarch/include/uapi/asm/bpf_perf_event.h [new file with mode: 0644]
arch/loongarch/net/Makefile [new file with mode: 0644]
arch/loongarch/net/bpf_jit.c [new file with mode: 0644]
arch/loongarch/net/bpf_jit.h [new file with mode: 0644]

index ab5373d0a24ffa024386c451e553c105bf11da55..b01f5cdb27e03d778dfa400e370037c39cd7abed 100644 (file)
@@ -1,5 +1,6 @@
 obj-y += kernel/
 obj-y += mm/
+obj-y += net/
 obj-y += vdso/
 
 # for cleaning
index 2837ac5413c08379a064c89898cb0689fbba8169..5c7c2a7762b790d03550da9a6f11acce0f84011b 100644 (file)
@@ -87,6 +87,7 @@ config LOONGARCH
        select HAVE_CONTEXT_TRACKING_USER
        select HAVE_DEBUG_STACKOVERFLOW
        select HAVE_DMA_CONTIGUOUS
+       select HAVE_EBPF_JIT
        select HAVE_EXIT_THREAD
        select HAVE_FAST_GUP
        select HAVE_GENERIC_VDSO
index 63df7efff276668448b7847c125b35bef9e7d23f..fce1843ceebb36a30e67fd01554bca37932dd383 100644 (file)
@@ -345,4 +345,225 @@ static inline bool unsigned_imm_check(unsigned long val, unsigned int bit)
        return val < (1UL << bit);
 }
 
+#define DEF_EMIT_REG0I26_FORMAT(NAME, OP)                              \
+static inline void emit_##NAME(union loongarch_instruction *insn,      \
+                              int offset)                              \
+{                                                                      \
+       unsigned int immediate_l, immediate_h;                          \
+                                                                       \
+       immediate_l = offset & 0xffff;                                  \
+       offset >>= 16;                                                  \
+       immediate_h = offset & 0x3ff;                                   \
+                                                                       \
+       insn->reg0i26_format.opcode = OP;                               \
+       insn->reg0i26_format.immediate_l = immediate_l;                 \
+       insn->reg0i26_format.immediate_h = immediate_h;                 \
+}
+
+DEF_EMIT_REG0I26_FORMAT(b, b_op)
+
+#define DEF_EMIT_REG1I20_FORMAT(NAME, OP)                              \
+static inline void emit_##NAME(union loongarch_instruction *insn,      \
+                              enum loongarch_gpr rd, int imm)          \
+{                                                                      \
+       insn->reg1i20_format.opcode = OP;                               \
+       insn->reg1i20_format.immediate = imm;                           \
+       insn->reg1i20_format.rd = rd;                                   \
+}
+
+DEF_EMIT_REG1I20_FORMAT(lu12iw, lu12iw_op)
+DEF_EMIT_REG1I20_FORMAT(lu32id, lu32id_op)
+DEF_EMIT_REG1I20_FORMAT(pcaddu18i, pcaddu18i_op)
+
+#define DEF_EMIT_REG2_FORMAT(NAME, OP)                                 \
+static inline void emit_##NAME(union loongarch_instruction *insn,      \
+                              enum loongarch_gpr rd,                   \
+                              enum loongarch_gpr rj)                   \
+{                                                                      \
+       insn->reg2_format.opcode = OP;                                  \
+       insn->reg2_format.rd = rd;                                      \
+       insn->reg2_format.rj = rj;                                      \
+}
+
+DEF_EMIT_REG2_FORMAT(revb2h, revb2h_op)
+DEF_EMIT_REG2_FORMAT(revb2w, revb2w_op)
+DEF_EMIT_REG2_FORMAT(revbd, revbd_op)
+
+#define DEF_EMIT_REG2I5_FORMAT(NAME, OP)                               \
+static inline void emit_##NAME(union loongarch_instruction *insn,      \
+                              enum loongarch_gpr rd,                   \
+                              enum loongarch_gpr rj,                   \
+                              int imm)                                 \
+{                                                                      \
+       insn->reg2i5_format.opcode = OP;                                \
+       insn->reg2i5_format.immediate = imm;                            \
+       insn->reg2i5_format.rd = rd;                                    \
+       insn->reg2i5_format.rj = rj;                                    \
+}
+
+DEF_EMIT_REG2I5_FORMAT(slliw, slliw_op)
+DEF_EMIT_REG2I5_FORMAT(srliw, srliw_op)
+DEF_EMIT_REG2I5_FORMAT(sraiw, sraiw_op)
+
+#define DEF_EMIT_REG2I6_FORMAT(NAME, OP)                               \
+static inline void emit_##NAME(union loongarch_instruction *insn,      \
+                              enum loongarch_gpr rd,                   \
+                              enum loongarch_gpr rj,                   \
+                              int imm)                                 \
+{                                                                      \
+       insn->reg2i6_format.opcode = OP;                                \
+       insn->reg2i6_format.immediate = imm;                            \
+       insn->reg2i6_format.rd = rd;                                    \
+       insn->reg2i6_format.rj = rj;                                    \
+}
+
+DEF_EMIT_REG2I6_FORMAT(sllid, sllid_op)
+DEF_EMIT_REG2I6_FORMAT(srlid, srlid_op)
+DEF_EMIT_REG2I6_FORMAT(sraid, sraid_op)
+
+#define DEF_EMIT_REG2I12_FORMAT(NAME, OP)                              \
+static inline void emit_##NAME(union loongarch_instruction *insn,      \
+                              enum loongarch_gpr rd,                   \
+                              enum loongarch_gpr rj,                   \
+                              int imm)                                 \
+{                                                                      \
+       insn->reg2i12_format.opcode = OP;                               \
+       insn->reg2i12_format.immediate = imm;                           \
+       insn->reg2i12_format.rd = rd;                                   \
+       insn->reg2i12_format.rj = rj;                                   \
+}
+
+DEF_EMIT_REG2I12_FORMAT(addiw, addiw_op)
+DEF_EMIT_REG2I12_FORMAT(addid, addid_op)
+DEF_EMIT_REG2I12_FORMAT(lu52id, lu52id_op)
+DEF_EMIT_REG2I12_FORMAT(andi, andi_op)
+DEF_EMIT_REG2I12_FORMAT(ori, ori_op)
+DEF_EMIT_REG2I12_FORMAT(xori, xori_op)
+DEF_EMIT_REG2I12_FORMAT(ldbu, ldbu_op)
+DEF_EMIT_REG2I12_FORMAT(ldhu, ldhu_op)
+DEF_EMIT_REG2I12_FORMAT(ldwu, ldwu_op)
+DEF_EMIT_REG2I12_FORMAT(ldd, ldd_op)
+DEF_EMIT_REG2I12_FORMAT(stb, stb_op)
+DEF_EMIT_REG2I12_FORMAT(sth, sth_op)
+DEF_EMIT_REG2I12_FORMAT(stw, stw_op)
+DEF_EMIT_REG2I12_FORMAT(std, std_op)
+
+#define DEF_EMIT_REG2I14_FORMAT(NAME, OP)                              \
+static inline void emit_##NAME(union loongarch_instruction *insn,      \
+                              enum loongarch_gpr rd,                   \
+                              enum loongarch_gpr rj,                   \
+                              int imm)                                 \
+{                                                                      \
+       insn->reg2i14_format.opcode = OP;                               \
+       insn->reg2i14_format.immediate = imm;                           \
+       insn->reg2i14_format.rd = rd;                                   \
+       insn->reg2i14_format.rj = rj;                                   \
+}
+
+DEF_EMIT_REG2I14_FORMAT(llw, llw_op)
+DEF_EMIT_REG2I14_FORMAT(scw, scw_op)
+DEF_EMIT_REG2I14_FORMAT(lld, lld_op)
+DEF_EMIT_REG2I14_FORMAT(scd, scd_op)
+DEF_EMIT_REG2I14_FORMAT(ldptrw, ldptrw_op)
+DEF_EMIT_REG2I14_FORMAT(stptrw, stptrw_op)
+DEF_EMIT_REG2I14_FORMAT(ldptrd, ldptrd_op)
+DEF_EMIT_REG2I14_FORMAT(stptrd, stptrd_op)
+
+#define DEF_EMIT_REG2I16_FORMAT(NAME, OP)                              \
+static inline void emit_##NAME(union loongarch_instruction *insn,      \
+                              enum loongarch_gpr rj,                   \
+                              enum loongarch_gpr rd,                   \
+                              int offset)                              \
+{                                                                      \
+       insn->reg2i16_format.opcode = OP;                               \
+       insn->reg2i16_format.immediate = offset;                        \
+       insn->reg2i16_format.rj = rj;                                   \
+       insn->reg2i16_format.rd = rd;                                   \
+}
+
+DEF_EMIT_REG2I16_FORMAT(beq, beq_op)
+DEF_EMIT_REG2I16_FORMAT(bne, bne_op)
+DEF_EMIT_REG2I16_FORMAT(blt, blt_op)
+DEF_EMIT_REG2I16_FORMAT(bge, bge_op)
+DEF_EMIT_REG2I16_FORMAT(bltu, bltu_op)
+DEF_EMIT_REG2I16_FORMAT(bgeu, bgeu_op)
+DEF_EMIT_REG2I16_FORMAT(jirl, jirl_op)
+
+#define DEF_EMIT_REG2BSTRD_FORMAT(NAME, OP)                            \
+static inline void emit_##NAME(union loongarch_instruction *insn,      \
+                              enum loongarch_gpr rd,                   \
+                              enum loongarch_gpr rj,                   \
+                              int msbd,                                \
+                              int lsbd)                                \
+{                                                                      \
+       insn->reg2bstrd_format.opcode = OP;                             \
+       insn->reg2bstrd_format.msbd = msbd;                             \
+       insn->reg2bstrd_format.lsbd = lsbd;                             \
+       insn->reg2bstrd_format.rj = rj;                                 \
+       insn->reg2bstrd_format.rd = rd;                                 \
+}
+
+DEF_EMIT_REG2BSTRD_FORMAT(bstrpickd, bstrpickd_op)
+
+#define DEF_EMIT_REG3_FORMAT(NAME, OP)                                 \
+static inline void emit_##NAME(union loongarch_instruction *insn,      \
+                              enum loongarch_gpr rd,                   \
+                              enum loongarch_gpr rj,                   \
+                              enum loongarch_gpr rk)                   \
+{                                                                      \
+       insn->reg3_format.opcode = OP;                                  \
+       insn->reg3_format.rd = rd;                                      \
+       insn->reg3_format.rj = rj;                                      \
+       insn->reg3_format.rk = rk;                                      \
+}
+
+DEF_EMIT_REG3_FORMAT(addd, addd_op)
+DEF_EMIT_REG3_FORMAT(subd, subd_op)
+DEF_EMIT_REG3_FORMAT(muld, muld_op)
+DEF_EMIT_REG3_FORMAT(divdu, divdu_op)
+DEF_EMIT_REG3_FORMAT(moddu, moddu_op)
+DEF_EMIT_REG3_FORMAT(and, and_op)
+DEF_EMIT_REG3_FORMAT(or, or_op)
+DEF_EMIT_REG3_FORMAT(xor, xor_op)
+DEF_EMIT_REG3_FORMAT(sllw, sllw_op)
+DEF_EMIT_REG3_FORMAT(slld, slld_op)
+DEF_EMIT_REG3_FORMAT(srlw, srlw_op)
+DEF_EMIT_REG3_FORMAT(srld, srld_op)
+DEF_EMIT_REG3_FORMAT(sraw, sraw_op)
+DEF_EMIT_REG3_FORMAT(srad, srad_op)
+DEF_EMIT_REG3_FORMAT(ldxbu, ldxbu_op)
+DEF_EMIT_REG3_FORMAT(ldxhu, ldxhu_op)
+DEF_EMIT_REG3_FORMAT(ldxwu, ldxwu_op)
+DEF_EMIT_REG3_FORMAT(ldxd, ldxd_op)
+DEF_EMIT_REG3_FORMAT(stxb, stxb_op)
+DEF_EMIT_REG3_FORMAT(stxh, stxh_op)
+DEF_EMIT_REG3_FORMAT(stxw, stxw_op)
+DEF_EMIT_REG3_FORMAT(stxd, stxd_op)
+DEF_EMIT_REG3_FORMAT(amaddw, amaddw_op)
+DEF_EMIT_REG3_FORMAT(amaddd, amaddd_op)
+DEF_EMIT_REG3_FORMAT(amandw, amandw_op)
+DEF_EMIT_REG3_FORMAT(amandd, amandd_op)
+DEF_EMIT_REG3_FORMAT(amorw, amorw_op)
+DEF_EMIT_REG3_FORMAT(amord, amord_op)
+DEF_EMIT_REG3_FORMAT(amxorw, amxorw_op)
+DEF_EMIT_REG3_FORMAT(amxord, amxord_op)
+DEF_EMIT_REG3_FORMAT(amswapw, amswapw_op)
+DEF_EMIT_REG3_FORMAT(amswapd, amswapd_op)
+
+#define DEF_EMIT_REG3SA2_FORMAT(NAME, OP)                              \
+static inline void emit_##NAME(union loongarch_instruction *insn,      \
+                              enum loongarch_gpr rd,                   \
+                              enum loongarch_gpr rj,                   \
+                              enum loongarch_gpr rk,                   \
+                              int imm)                                 \
+{                                                                      \
+       insn->reg3sa2_format.opcode = OP;                               \
+       insn->reg3sa2_format.immediate = imm;                           \
+       insn->reg3sa2_format.rd = rd;                                   \
+       insn->reg3sa2_format.rj = rj;                                   \
+       insn->reg3sa2_format.rk = rk;                                   \
+}
+
+DEF_EMIT_REG3SA2_FORMAT(alsld, alsld_op)
+
 #endif /* _ASM_INST_H */
diff --git a/arch/loongarch/include/uapi/asm/bpf_perf_event.h b/arch/loongarch/include/uapi/asm/bpf_perf_event.h
new file mode 100644 (file)
index 0000000..eb6e2fd
--- /dev/null
@@ -0,0 +1,9 @@
+/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
+#ifndef _UAPI__ASM_BPF_PERF_EVENT_H__
+#define _UAPI__ASM_BPF_PERF_EVENT_H__
+
+#include <linux/ptrace.h>
+
+typedef struct user_pt_regs bpf_user_pt_regs_t;
+
+#endif /* _UAPI__ASM_BPF_PERF_EVENT_H__ */
diff --git a/arch/loongarch/net/Makefile b/arch/loongarch/net/Makefile
new file mode 100644 (file)
index 0000000..1ec12a0
--- /dev/null
@@ -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 (file)
index 0000000..43f0a98
--- /dev/null
@@ -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 (file)
index 0000000..e665ddb
--- /dev/null
@@ -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;
+}