treewide: remove redundant IS_ERR() before error code check

[linux/fpc-iii.git] / arch / riscv / net / bpf_jit_comp.c

// SPDX-License-Identifier: GPL-2.0
/* BPF JIT compiler for RV64G
 *
 * Copyright(c) 2019 Björn Töpel <bjorn.topel@gmail.com>
 *
 */

#include <linux/bpf.h>
#include <linux/filter.h>
#include <asm/cacheflush.h>

enum {
        RV_REG_ZERO =   0,      /* The constant value 0 */
        RV_REG_RA =     1,      /* Return address */
        RV_REG_SP =     2,      /* Stack pointer */
        RV_REG_GP =     3,      /* Global pointer */
        RV_REG_TP =     4,      /* Thread pointer */
        RV_REG_T0 =     5,      /* Temporaries */
        RV_REG_T1 =     6,
        RV_REG_T2 =     7,
        RV_REG_FP =     8,
        RV_REG_S1 =     9,      /* Saved registers */
        RV_REG_A0 =     10,     /* Function argument/return values */
        RV_REG_A1 =     11,     /* Function arguments */
        RV_REG_A2 =     12,
        RV_REG_A3 =     13,
        RV_REG_A4 =     14,
        RV_REG_A5 =     15,
        RV_REG_A6 =     16,
        RV_REG_A7 =     17,
        RV_REG_S2 =     18,     /* Saved registers */
        RV_REG_S3 =     19,
        RV_REG_S4 =     20,
        RV_REG_S5 =     21,
        RV_REG_S6 =     22,
        RV_REG_S7 =     23,
        RV_REG_S8 =     24,
        RV_REG_S9 =     25,
        RV_REG_S10 =    26,
        RV_REG_S11 =    27,
        RV_REG_T3 =     28,     /* Temporaries */
        RV_REG_T4 =     29,
        RV_REG_T5 =     30,
        RV_REG_T6 =     31,
};

#define RV_REG_TCC RV_REG_A6
#define RV_REG_TCC_SAVED RV_REG_S6 /* Store A6 in S6 if program do calls */

static const int regmap[] = {
        [BPF_REG_0] =   RV_REG_A5,
        [BPF_REG_1] =   RV_REG_A0,
        [BPF_REG_2] =   RV_REG_A1,
        [BPF_REG_3] =   RV_REG_A2,
        [BPF_REG_4] =   RV_REG_A3,
        [BPF_REG_5] =   RV_REG_A4,
        [BPF_REG_6] =   RV_REG_S1,
        [BPF_REG_7] =   RV_REG_S2,
        [BPF_REG_8] =   RV_REG_S3,
        [BPF_REG_9] =   RV_REG_S4,
        [BPF_REG_FP] =  RV_REG_S5,
        [BPF_REG_AX] =  RV_REG_T0,
};

enum {
        RV_CTX_F_SEEN_TAIL_CALL =       0,
        RV_CTX_F_SEEN_CALL =            RV_REG_RA,
        RV_CTX_F_SEEN_S1 =              RV_REG_S1,
        RV_CTX_F_SEEN_S2 =              RV_REG_S2,
        RV_CTX_F_SEEN_S3 =              RV_REG_S3,
        RV_CTX_F_SEEN_S4 =              RV_REG_S4,
        RV_CTX_F_SEEN_S5 =              RV_REG_S5,
        RV_CTX_F_SEEN_S6 =              RV_REG_S6,
};

struct rv_jit_context {
        struct bpf_prog *prog;
        u32 *insns; /* RV insns */
        int ninsns;
        int epilogue_offset;
        int *offset; /* BPF to RV */
        unsigned long flags;
        int stack_size;
};

struct rv_jit_data {
        struct bpf_binary_header *header;
        u8 *image;
        struct rv_jit_context ctx;
};

static u8 bpf_to_rv_reg(int bpf_reg, struct rv_jit_context *ctx)
{
        u8 reg = regmap[bpf_reg];

        switch (reg) {
        case RV_CTX_F_SEEN_S1:
        case RV_CTX_F_SEEN_S2:
        case RV_CTX_F_SEEN_S3:
        case RV_CTX_F_SEEN_S4:
        case RV_CTX_F_SEEN_S5:
        case RV_CTX_F_SEEN_S6:
                __set_bit(reg, &ctx->flags);
        }
        return reg;
};

static bool seen_reg(int reg, struct rv_jit_context *ctx)
{
        switch (reg) {
        case RV_CTX_F_SEEN_CALL:
        case RV_CTX_F_SEEN_S1:
        case RV_CTX_F_SEEN_S2:
        case RV_CTX_F_SEEN_S3:
        case RV_CTX_F_SEEN_S4:
        case RV_CTX_F_SEEN_S5:
        case RV_CTX_F_SEEN_S6:
                return test_bit(reg, &ctx->flags);
        }
        return false;
}

static void mark_fp(struct rv_jit_context *ctx)
{
        __set_bit(RV_CTX_F_SEEN_S5, &ctx->flags);
}

static void mark_call(struct rv_jit_context *ctx)
{
        __set_bit(RV_CTX_F_SEEN_CALL, &ctx->flags);
}

static bool seen_call(struct rv_jit_context *ctx)
{
        return test_bit(RV_CTX_F_SEEN_CALL, &ctx->flags);
}

static void mark_tail_call(struct rv_jit_context *ctx)
{
        __set_bit(RV_CTX_F_SEEN_TAIL_CALL, &ctx->flags);
}

static bool seen_tail_call(struct rv_jit_context *ctx)
{
        return test_bit(RV_CTX_F_SEEN_TAIL_CALL, &ctx->flags);
}

static u8 rv_tail_call_reg(struct rv_jit_context *ctx)
{
        mark_tail_call(ctx);

        if (seen_call(ctx)) {
                __set_bit(RV_CTX_F_SEEN_S6, &ctx->flags);
                return RV_REG_S6;
        }
        return RV_REG_A6;
}

static void emit(const u32 insn, struct rv_jit_context *ctx)
{
        if (ctx->insns)
                ctx->insns[ctx->ninsns] = insn;

        ctx->ninsns++;
}

static u32 rv_r_insn(u8 funct7, u8 rs2, u8 rs1, u8 funct3, u8 rd, u8 opcode)
{
        return (funct7 << 25) | (rs2 << 20) | (rs1 << 15) | (funct3 << 12) |
                (rd << 7) | opcode;
}

static u32 rv_i_insn(u16 imm11_0, u8 rs1, u8 funct3, u8 rd, u8 opcode)
{
        return (imm11_0 << 20) | (rs1 << 15) | (funct3 << 12) | (rd << 7) |
                opcode;
}

static u32 rv_s_insn(u16 imm11_0, u8 rs2, u8 rs1, u8 funct3, u8 opcode)
{
        u8 imm11_5 = imm11_0 >> 5, imm4_0 = imm11_0 & 0x1f;

        return (imm11_5 << 25) | (rs2 << 20) | (rs1 << 15) | (funct3 << 12) |
                (imm4_0 << 7) | opcode;
}

static u32 rv_sb_insn(u16 imm12_1, u8 rs2, u8 rs1, u8 funct3, u8 opcode)
{
        u8 imm12 = ((imm12_1 & 0x800) >> 5) | ((imm12_1 & 0x3f0) >> 4);
        u8 imm4_1 = ((imm12_1 & 0xf) << 1) | ((imm12_1 & 0x400) >> 10);

        return (imm12 << 25) | (rs2 << 20) | (rs1 << 15) | (funct3 << 12) |
                (imm4_1 << 7) | opcode;
}

static u32 rv_u_insn(u32 imm31_12, u8 rd, u8 opcode)
{
        return (imm31_12 << 12) | (rd << 7) | opcode;
}

static u32 rv_uj_insn(u32 imm20_1, u8 rd, u8 opcode)
{
        u32 imm;

        imm = (imm20_1 & 0x80000) |  ((imm20_1 & 0x3ff) << 9) |
              ((imm20_1 & 0x400) >> 2) | ((imm20_1 & 0x7f800) >> 11);

        return (imm << 12) | (rd << 7) | opcode;
}

static u32 rv_amo_insn(u8 funct5, u8 aq, u8 rl, u8 rs2, u8 rs1,
                       u8 funct3, u8 rd, u8 opcode)
{
        u8 funct7 = (funct5 << 2) | (aq << 1) | rl;

        return rv_r_insn(funct7, rs2, rs1, funct3, rd, opcode);
}

static u32 rv_addiw(u8 rd, u8 rs1, u16 imm11_0)
{
        return rv_i_insn(imm11_0, rs1, 0, rd, 0x1b);
}

static u32 rv_addi(u8 rd, u8 rs1, u16 imm11_0)
{
        return rv_i_insn(imm11_0, rs1, 0, rd, 0x13);
}

static u32 rv_addw(u8 rd, u8 rs1, u8 rs2)
{
        return rv_r_insn(0, rs2, rs1, 0, rd, 0x3b);
}

static u32 rv_add(u8 rd, u8 rs1, u8 rs2)
{
        return rv_r_insn(0, rs2, rs1, 0, rd, 0x33);
}

static u32 rv_subw(u8 rd, u8 rs1, u8 rs2)
{
        return rv_r_insn(0x20, rs2, rs1, 0, rd, 0x3b);
}

static u32 rv_sub(u8 rd, u8 rs1, u8 rs2)
{
        return rv_r_insn(0x20, rs2, rs1, 0, rd, 0x33);
}

static u32 rv_and(u8 rd, u8 rs1, u8 rs2)
{
        return rv_r_insn(0, rs2, rs1, 7, rd, 0x33);
}

static u32 rv_or(u8 rd, u8 rs1, u8 rs2)
{
        return rv_r_insn(0, rs2, rs1, 6, rd, 0x33);
}

static u32 rv_xor(u8 rd, u8 rs1, u8 rs2)
{
        return rv_r_insn(0, rs2, rs1, 4, rd, 0x33);
}

static u32 rv_mulw(u8 rd, u8 rs1, u8 rs2)
{
        return rv_r_insn(1, rs2, rs1, 0, rd, 0x3b);
}

static u32 rv_mul(u8 rd, u8 rs1, u8 rs2)
{
        return rv_r_insn(1, rs2, rs1, 0, rd, 0x33);
}

static u32 rv_divuw(u8 rd, u8 rs1, u8 rs2)
{
        return rv_r_insn(1, rs2, rs1, 5, rd, 0x3b);
}

static u32 rv_divu(u8 rd, u8 rs1, u8 rs2)
{
        return rv_r_insn(1, rs2, rs1, 5, rd, 0x33);
}

static u32 rv_remuw(u8 rd, u8 rs1, u8 rs2)
{
        return rv_r_insn(1, rs2, rs1, 7, rd, 0x3b);
}

static u32 rv_remu(u8 rd, u8 rs1, u8 rs2)
{
        return rv_r_insn(1, rs2, rs1, 7, rd, 0x33);
}

static u32 rv_sllw(u8 rd, u8 rs1, u8 rs2)
{
        return rv_r_insn(0, rs2, rs1, 1, rd, 0x3b);
}

static u32 rv_sll(u8 rd, u8 rs1, u8 rs2)
{
        return rv_r_insn(0, rs2, rs1, 1, rd, 0x33);
}

static u32 rv_srlw(u8 rd, u8 rs1, u8 rs2)
{
        return rv_r_insn(0, rs2, rs1, 5, rd, 0x3b);
}

static u32 rv_srl(u8 rd, u8 rs1, u8 rs2)
{
        return rv_r_insn(0, rs2, rs1, 5, rd, 0x33);
}

static u32 rv_sraw(u8 rd, u8 rs1, u8 rs2)
{
        return rv_r_insn(0x20, rs2, rs1, 5, rd, 0x3b);
}

static u32 rv_sra(u8 rd, u8 rs1, u8 rs2)
{
        return rv_r_insn(0x20, rs2, rs1, 5, rd, 0x33);
}

static u32 rv_lui(u8 rd, u32 imm31_12)
{
        return rv_u_insn(imm31_12, rd, 0x37);
}

static u32 rv_slli(u8 rd, u8 rs1, u16 imm11_0)
{
        return rv_i_insn(imm11_0, rs1, 1, rd, 0x13);
}

static u32 rv_andi(u8 rd, u8 rs1, u16 imm11_0)
{
        return rv_i_insn(imm11_0, rs1, 7, rd, 0x13);
}

static u32 rv_ori(u8 rd, u8 rs1, u16 imm11_0)
{
        return rv_i_insn(imm11_0, rs1, 6, rd, 0x13);
}

static u32 rv_xori(u8 rd, u8 rs1, u16 imm11_0)
{
        return rv_i_insn(imm11_0, rs1, 4, rd, 0x13);
}

static u32 rv_slliw(u8 rd, u8 rs1, u16 imm11_0)
{
        return rv_i_insn(imm11_0, rs1, 1, rd, 0x1b);
}

static u32 rv_srliw(u8 rd, u8 rs1, u16 imm11_0)
{
        return rv_i_insn(imm11_0, rs1, 5, rd, 0x1b);
}

static u32 rv_srli(u8 rd, u8 rs1, u16 imm11_0)
{
        return rv_i_insn(imm11_0, rs1, 5, rd, 0x13);
}

static u32 rv_sraiw(u8 rd, u8 rs1, u16 imm11_0)
{
        return rv_i_insn(0x400 | imm11_0, rs1, 5, rd, 0x1b);
}

static u32 rv_srai(u8 rd, u8 rs1, u16 imm11_0)
{
        return rv_i_insn(0x400 | imm11_0, rs1, 5, rd, 0x13);
}

static u32 rv_jal(u8 rd, u32 imm20_1)
{
        return rv_uj_insn(imm20_1, rd, 0x6f);
}

static u32 rv_jalr(u8 rd, u8 rs1, u16 imm11_0)
{
        return rv_i_insn(imm11_0, rs1, 0, rd, 0x67);
}

static u32 rv_beq(u8 rs1, u8 rs2, u16 imm12_1)
{
        return rv_sb_insn(imm12_1, rs2, rs1, 0, 0x63);
}

static u32 rv_bltu(u8 rs1, u8 rs2, u16 imm12_1)
{
        return rv_sb_insn(imm12_1, rs2, rs1, 6, 0x63);
}

static u32 rv_bgeu(u8 rs1, u8 rs2, u16 imm12_1)
{
        return rv_sb_insn(imm12_1, rs2, rs1, 7, 0x63);
}

static u32 rv_bne(u8 rs1, u8 rs2, u16 imm12_1)
{
        return rv_sb_insn(imm12_1, rs2, rs1, 1, 0x63);
}

static u32 rv_blt(u8 rs1, u8 rs2, u16 imm12_1)
{
        return rv_sb_insn(imm12_1, rs2, rs1, 4, 0x63);
}

static u32 rv_bge(u8 rs1, u8 rs2, u16 imm12_1)
{
        return rv_sb_insn(imm12_1, rs2, rs1, 5, 0x63);
}

static u32 rv_sb(u8 rs1, u16 imm11_0, u8 rs2)
{
        return rv_s_insn(imm11_0, rs2, rs1, 0, 0x23);
}

static u32 rv_sh(u8 rs1, u16 imm11_0, u8 rs2)
{
        return rv_s_insn(imm11_0, rs2, rs1, 1, 0x23);
}

static u32 rv_sw(u8 rs1, u16 imm11_0, u8 rs2)
{
        return rv_s_insn(imm11_0, rs2, rs1, 2, 0x23);
}

static u32 rv_sd(u8 rs1, u16 imm11_0, u8 rs2)
{
        return rv_s_insn(imm11_0, rs2, rs1, 3, 0x23);
}

static u32 rv_lbu(u8 rd, u16 imm11_0, u8 rs1)
{
        return rv_i_insn(imm11_0, rs1, 4, rd, 0x03);
}

static u32 rv_lhu(u8 rd, u16 imm11_0, u8 rs1)
{
        return rv_i_insn(imm11_0, rs1, 5, rd, 0x03);
}

static u32 rv_lwu(u8 rd, u16 imm11_0, u8 rs1)
{
        return rv_i_insn(imm11_0, rs1, 6, rd, 0x03);
}

static u32 rv_ld(u8 rd, u16 imm11_0, u8 rs1)
{
        return rv_i_insn(imm11_0, rs1, 3, rd, 0x03);
}

static u32 rv_amoadd_w(u8 rd, u8 rs2, u8 rs1, u8 aq, u8 rl)
{
        return rv_amo_insn(0, aq, rl, rs2, rs1, 2, rd, 0x2f);
}

static u32 rv_amoadd_d(u8 rd, u8 rs2, u8 rs1, u8 aq, u8 rl)
{
        return rv_amo_insn(0, aq, rl, rs2, rs1, 3, rd, 0x2f);
}

static u32 rv_auipc(u8 rd, u32 imm31_12)
{
        return rv_u_insn(imm31_12, rd, 0x17);
}

static bool is_12b_int(s64 val)
{
        return -(1 << 11) <= val && val < (1 << 11);
}

static bool is_13b_int(s64 val)
{
        return -(1 << 12) <= val && val < (1 << 12);
}

static bool is_21b_int(s64 val)
{
        return -(1L << 20) <= val && val < (1L << 20);
}

static bool is_32b_int(s64 val)
{
        return -(1L << 31) <= val && val < (1L << 31);
}

static int is_12b_check(int off, int insn)
{
        if (!is_12b_int(off)) {
                pr_err("bpf-jit: insn=%d 12b < offset=%d not supported yet!\n",
                       insn, (int)off);
                return -1;
        }
        return 0;
}

static void emit_imm(u8 rd, s64 val, struct rv_jit_context *ctx)
{
        /* Note that the immediate from the add is sign-extended,
         * which means that we need to compensate this by adding 2^12,
         * when the 12th bit is set. A simpler way of doing this, and
         * getting rid of the check, is to just add 2**11 before the
         * shift. The "Loading a 32-Bit constant" example from the
         * "Computer Organization and Design, RISC-V edition" book by
         * Patterson/Hennessy highlights this fact.
         *
         * This also means that we need to process LSB to MSB.
         */
        s64 upper = (val + (1 << 11)) >> 12, lower = val & 0xfff;
        int shift;

        if (is_32b_int(val)) {
                if (upper)
                        emit(rv_lui(rd, upper), ctx);

                if (!upper) {
                        emit(rv_addi(rd, RV_REG_ZERO, lower), ctx);
                        return;
                }

                emit(rv_addiw(rd, rd, lower), ctx);
                return;
        }

        shift = __ffs(upper);
        upper >>= shift;
        shift += 12;

        emit_imm(rd, upper, ctx);

        emit(rv_slli(rd, rd, shift), ctx);
        if (lower)
                emit(rv_addi(rd, rd, lower), ctx);
}

static int rv_offset(int insn, int off, struct rv_jit_context *ctx)
{
        int from, to;

        off++; /* BPF branch is from PC+1, RV is from PC */
        from = (insn > 0) ? ctx->offset[insn - 1] : 0;
        to = (insn + off > 0) ? ctx->offset[insn + off - 1] : 0;
        return (to - from) << 2;
}

static int epilogue_offset(struct rv_jit_context *ctx)
{
        int to = ctx->epilogue_offset, from = ctx->ninsns;

        return (to - from) << 2;
}

static void __build_epilogue(bool is_tail_call, struct rv_jit_context *ctx)
{
        int stack_adjust = ctx->stack_size, store_offset = stack_adjust - 8;

        if (seen_reg(RV_REG_RA, ctx)) {
                emit(rv_ld(RV_REG_RA, store_offset, RV_REG_SP), ctx);
                store_offset -= 8;
        }
        emit(rv_ld(RV_REG_FP, store_offset, RV_REG_SP), ctx);
        store_offset -= 8;
        if (seen_reg(RV_REG_S1, ctx)) {
                emit(rv_ld(RV_REG_S1, store_offset, RV_REG_SP), ctx);
                store_offset -= 8;
        }
        if (seen_reg(RV_REG_S2, ctx)) {
                emit(rv_ld(RV_REG_S2, store_offset, RV_REG_SP), ctx);
                store_offset -= 8;
        }
        if (seen_reg(RV_REG_S3, ctx)) {
                emit(rv_ld(RV_REG_S3, store_offset, RV_REG_SP), ctx);
                store_offset -= 8;
        }
        if (seen_reg(RV_REG_S4, ctx)) {
                emit(rv_ld(RV_REG_S4, store_offset, RV_REG_SP), ctx);
                store_offset -= 8;
        }
        if (seen_reg(RV_REG_S5, ctx)) {
                emit(rv_ld(RV_REG_S5, store_offset, RV_REG_SP), ctx);
                store_offset -= 8;
        }
        if (seen_reg(RV_REG_S6, ctx)) {
                emit(rv_ld(RV_REG_S6, store_offset, RV_REG_SP), ctx);
                store_offset -= 8;
        }

        emit(rv_addi(RV_REG_SP, RV_REG_SP, stack_adjust), ctx);
        /* Set return value. */
        if (!is_tail_call)
                emit(rv_addi(RV_REG_A0, RV_REG_A5, 0), ctx);
        emit(rv_jalr(RV_REG_ZERO, is_tail_call ? RV_REG_T3 : RV_REG_RA,
                     is_tail_call ? 4 : 0), /* skip TCC init */
             ctx);
}

/* return -1 or inverted cond */
static int invert_bpf_cond(u8 cond)
{
        switch (cond) {
        case BPF_JEQ:
                return BPF_JNE;
        case BPF_JGT:
                return BPF_JLE;
        case BPF_JLT:
                return BPF_JGE;
        case BPF_JGE:
                return BPF_JLT;
        case BPF_JLE:
                return BPF_JGT;
        case BPF_JNE:
                return BPF_JEQ;
        case BPF_JSGT:
                return BPF_JSLE;
        case BPF_JSLT:
                return BPF_JSGE;
        case BPF_JSGE:
                return BPF_JSLT;
        case BPF_JSLE:
                return BPF_JSGT;
        }
        return -1;
}

static void emit_bcc(u8 cond, u8 rd, u8 rs, int rvoff,
                     struct rv_jit_context *ctx)
{
        switch (cond) {
        case BPF_JEQ:
                emit(rv_beq(rd, rs, rvoff >> 1), ctx);
                return;
        case BPF_JGT:
                emit(rv_bltu(rs, rd, rvoff >> 1), ctx);
                return;
        case BPF_JLT:
                emit(rv_bltu(rd, rs, rvoff >> 1), ctx);
                return;
        case BPF_JGE:
                emit(rv_bgeu(rd, rs, rvoff >> 1), ctx);
                return;
        case BPF_JLE:
                emit(rv_bgeu(rs, rd, rvoff >> 1), ctx);
                return;
        case BPF_JNE:
                emit(rv_bne(rd, rs, rvoff >> 1), ctx);
                return;
        case BPF_JSGT:
                emit(rv_blt(rs, rd, rvoff >> 1), ctx);
                return;
        case BPF_JSLT:
                emit(rv_blt(rd, rs, rvoff >> 1), ctx);
                return;
        case BPF_JSGE:
                emit(rv_bge(rd, rs, rvoff >> 1), ctx);
                return;
        case BPF_JSLE:
                emit(rv_bge(rs, rd, rvoff >> 1), ctx);
        }
}

static void emit_branch(u8 cond, u8 rd, u8 rs, int rvoff,
                        struct rv_jit_context *ctx)
{
        s64 upper, lower;

        if (is_13b_int(rvoff)) {
                emit_bcc(cond, rd, rs, rvoff, ctx);
                return;
        }

        /* Adjust for jal */
        rvoff -= 4;

        /* Transform, e.g.:
         *   bne rd,rs,foo
         * to
         *   beq rd,rs,<.L1>
         *   (auipc foo)
         *   jal(r) foo
         * .L1
         */
        cond = invert_bpf_cond(cond);
        if (is_21b_int(rvoff)) {
                emit_bcc(cond, rd, rs, 8, ctx);
                emit(rv_jal(RV_REG_ZERO, rvoff >> 1), ctx);
                return;
        }

        /* 32b No need for an additional rvoff adjustment, since we
         * get that from the auipc at PC', where PC = PC' + 4.
         */
        upper = (rvoff + (1 << 11)) >> 12;
        lower = rvoff & 0xfff;

        emit_bcc(cond, rd, rs, 12, ctx);
        emit(rv_auipc(RV_REG_T1, upper), ctx);
        emit(rv_jalr(RV_REG_ZERO, RV_REG_T1, lower), ctx);
}

static void emit_zext_32(u8 reg, struct rv_jit_context *ctx)
{
        emit(rv_slli(reg, reg, 32), ctx);
        emit(rv_srli(reg, reg, 32), ctx);
}

static int emit_bpf_tail_call(int insn, struct rv_jit_context *ctx)
{
        int tc_ninsn, off, start_insn = ctx->ninsns;
        u8 tcc = rv_tail_call_reg(ctx);

        /* a0: &ctx
         * a1: &array
         * a2: index
         *
         * if (index >= array->map.max_entries)
         *      goto out;
         */
        tc_ninsn = insn ? ctx->offset[insn] - ctx->offset[insn - 1] :
                   ctx->offset[0];
        emit_zext_32(RV_REG_A2, ctx);

        off = offsetof(struct bpf_array, map.max_entries);
        if (is_12b_check(off, insn))
                return -1;
        emit(rv_lwu(RV_REG_T1, off, RV_REG_A1), ctx);
        off = (tc_ninsn - (ctx->ninsns - start_insn)) << 2;
        emit_branch(BPF_JGE, RV_REG_A2, RV_REG_T1, off, ctx);

        /* if (TCC-- < 0)
         *     goto out;
         */
        emit(rv_addi(RV_REG_T1, tcc, -1), ctx);
        off = (tc_ninsn - (ctx->ninsns - start_insn)) << 2;
        emit_branch(BPF_JSLT, tcc, RV_REG_ZERO, off, ctx);

        /* prog = array->ptrs[index];
         * if (!prog)
         *     goto out;
         */
        emit(rv_slli(RV_REG_T2, RV_REG_A2, 3), ctx);
        emit(rv_add(RV_REG_T2, RV_REG_T2, RV_REG_A1), ctx);
        off = offsetof(struct bpf_array, ptrs);
        if (is_12b_check(off, insn))
                return -1;
        emit(rv_ld(RV_REG_T2, off, RV_REG_T2), ctx);
        off = (tc_ninsn - (ctx->ninsns - start_insn)) << 2;
        emit_branch(BPF_JEQ, RV_REG_T2, RV_REG_ZERO, off, ctx);

        /* goto *(prog->bpf_func + 4); */
        off = offsetof(struct bpf_prog, bpf_func);
        if (is_12b_check(off, insn))
                return -1;
        emit(rv_ld(RV_REG_T3, off, RV_REG_T2), ctx);
        emit(rv_addi(RV_REG_TCC, RV_REG_T1, 0), ctx);
        __build_epilogue(true, ctx);
        return 0;
}

static void init_regs(u8 *rd, u8 *rs, const struct bpf_insn *insn,
                      struct rv_jit_context *ctx)
{
        u8 code = insn->code;

        switch (code) {
        case BPF_JMP | BPF_JA:
        case BPF_JMP | BPF_CALL:
        case BPF_JMP | BPF_EXIT:
        case BPF_JMP | BPF_TAIL_CALL:
                break;
        default:
                *rd = bpf_to_rv_reg(insn->dst_reg, ctx);
        }

        if (code & (BPF_ALU | BPF_X) || code & (BPF_ALU64 | BPF_X) ||
            code & (BPF_JMP | BPF_X) || code & (BPF_JMP32 | BPF_X) ||
            code & BPF_LDX || code & BPF_STX)
                *rs = bpf_to_rv_reg(insn->src_reg, ctx);
}

static void emit_zext_32_rd_rs(u8 *rd, u8 *rs, struct rv_jit_context *ctx)
{
        emit(rv_addi(RV_REG_T2, *rd, 0), ctx);
        emit_zext_32(RV_REG_T2, ctx);
        emit(rv_addi(RV_REG_T1, *rs, 0), ctx);
        emit_zext_32(RV_REG_T1, ctx);
        *rd = RV_REG_T2;
        *rs = RV_REG_T1;
}

static void emit_sext_32_rd_rs(u8 *rd, u8 *rs, struct rv_jit_context *ctx)
{
        emit(rv_addiw(RV_REG_T2, *rd, 0), ctx);
        emit(rv_addiw(RV_REG_T1, *rs, 0), ctx);
        *rd = RV_REG_T2;
        *rs = RV_REG_T1;
}

static void emit_zext_32_rd_t1(u8 *rd, struct rv_jit_context *ctx)
{
        emit(rv_addi(RV_REG_T2, *rd, 0), ctx);
        emit_zext_32(RV_REG_T2, ctx);
        emit_zext_32(RV_REG_T1, ctx);
        *rd = RV_REG_T2;
}

static void emit_sext_32_rd(u8 *rd, struct rv_jit_context *ctx)
{
        emit(rv_addiw(RV_REG_T2, *rd, 0), ctx);
        *rd = RV_REG_T2;
}

static void emit_jump_and_link(u8 rd, s64 rvoff, bool force_jalr,
                               struct rv_jit_context *ctx)
{
        s64 upper, lower;

        if (rvoff && is_21b_int(rvoff) && !force_jalr) {
                emit(rv_jal(rd, rvoff >> 1), ctx);
                return;
        }

        upper = (rvoff + (1 << 11)) >> 12;
        lower = rvoff & 0xfff;
        emit(rv_auipc(RV_REG_T1, upper), ctx);
        emit(rv_jalr(rd, RV_REG_T1, lower), ctx);
}

static bool is_signed_bpf_cond(u8 cond)
{
        return cond == BPF_JSGT || cond == BPF_JSLT ||
                cond == BPF_JSGE || cond == BPF_JSLE;
}

static int emit_call(bool fixed, u64 addr, struct rv_jit_context *ctx)
{
        s64 off = 0;
        u64 ip;
        u8 rd;

        if (addr && ctx->insns) {
                ip = (u64)(long)(ctx->insns + ctx->ninsns);
                off = addr - ip;
                if (!is_32b_int(off)) {
                        pr_err("bpf-jit: target call addr %pK is out of range\n",
                               (void *)addr);
                        return -ERANGE;
                }
        }

        emit_jump_and_link(RV_REG_RA, off, !fixed, ctx);
        rd = bpf_to_rv_reg(BPF_REG_0, ctx);
        emit(rv_addi(rd, RV_REG_A0, 0), ctx);
        return 0;
}

static int emit_insn(const struct bpf_insn *insn, struct rv_jit_context *ctx,
                     bool extra_pass)
{
        bool is64 = BPF_CLASS(insn->code) == BPF_ALU64 ||
                    BPF_CLASS(insn->code) == BPF_JMP;
        int s, e, rvoff, i = insn - ctx->prog->insnsi;
        struct bpf_prog_aux *aux = ctx->prog->aux;
        u8 rd = -1, rs = -1, code = insn->code;
        s16 off = insn->off;
        s32 imm = insn->imm;

        init_regs(&rd, &rs, insn, ctx);

        switch (code) {
        /* dst = src */
        case BPF_ALU | BPF_MOV | BPF_X:
        case BPF_ALU64 | BPF_MOV | BPF_X:
                if (imm == 1) {
                        /* Special mov32 for zext */
                        emit_zext_32(rd, ctx);
                        break;
                }
                emit(is64 ? rv_addi(rd, rs, 0) : rv_addiw(rd, rs, 0), ctx);
                if (!is64 && !aux->verifier_zext)
                        emit_zext_32(rd, ctx);
                break;

        /* dst = dst OP src */
        case BPF_ALU | BPF_ADD | BPF_X:
        case BPF_ALU64 | BPF_ADD | BPF_X:
                emit(is64 ? rv_add(rd, rd, rs) : rv_addw(rd, rd, rs), ctx);
                if (!is64 && !aux->verifier_zext)
                        emit_zext_32(rd, ctx);
                break;
        case BPF_ALU | BPF_SUB | BPF_X:
        case BPF_ALU64 | BPF_SUB | BPF_X:
                emit(is64 ? rv_sub(rd, rd, rs) : rv_subw(rd, rd, rs), ctx);
                if (!is64 && !aux->verifier_zext)
                        emit_zext_32(rd, ctx);
                break;
        case BPF_ALU | BPF_AND | BPF_X:
        case BPF_ALU64 | BPF_AND | BPF_X:
                emit(rv_and(rd, rd, rs), ctx);
                if (!is64 && !aux->verifier_zext)
                        emit_zext_32(rd, ctx);
                break;
        case BPF_ALU | BPF_OR | BPF_X:
        case BPF_ALU64 | BPF_OR | BPF_X:
                emit(rv_or(rd, rd, rs), ctx);
                if (!is64 && !aux->verifier_zext)
                        emit_zext_32(rd, ctx);
                break;
        case BPF_ALU | BPF_XOR | BPF_X:
        case BPF_ALU64 | BPF_XOR | BPF_X:
                emit(rv_xor(rd, rd, rs), ctx);
                if (!is64 && !aux->verifier_zext)
                        emit_zext_32(rd, ctx);
                break;
        case BPF_ALU | BPF_MUL | BPF_X:
        case BPF_ALU64 | BPF_MUL | BPF_X:
                emit(is64 ? rv_mul(rd, rd, rs) : rv_mulw(rd, rd, rs), ctx);
                if (!is64 && !aux->verifier_zext)
                        emit_zext_32(rd, ctx);
                break;
        case BPF_ALU | BPF_DIV | BPF_X:
        case BPF_ALU64 | BPF_DIV | BPF_X:
                emit(is64 ? rv_divu(rd, rd, rs) : rv_divuw(rd, rd, rs), ctx);
                if (!is64 && !aux->verifier_zext)
                        emit_zext_32(rd, ctx);
                break;
        case BPF_ALU | BPF_MOD | BPF_X:
        case BPF_ALU64 | BPF_MOD | BPF_X:
                emit(is64 ? rv_remu(rd, rd, rs) : rv_remuw(rd, rd, rs), ctx);
                if (!is64 && !aux->verifier_zext)
                        emit_zext_32(rd, ctx);
                break;
        case BPF_ALU | BPF_LSH | BPF_X:
        case BPF_ALU64 | BPF_LSH | BPF_X:
                emit(is64 ? rv_sll(rd, rd, rs) : rv_sllw(rd, rd, rs), ctx);
                if (!is64)
                        emit_zext_32(rd, ctx);
                break;
        case BPF_ALU | BPF_RSH | BPF_X:
        case BPF_ALU64 | BPF_RSH | BPF_X:
                emit(is64 ? rv_srl(rd, rd, rs) : rv_srlw(rd, rd, rs), ctx);
                if (!is64 && !aux->verifier_zext)
                        emit_zext_32(rd, ctx);
                break;
        case BPF_ALU | BPF_ARSH | BPF_X:
        case BPF_ALU64 | BPF_ARSH | BPF_X:
                emit(is64 ? rv_sra(rd, rd, rs) : rv_sraw(rd, rd, rs), ctx);
                if (!is64 && !aux->verifier_zext)
                        emit_zext_32(rd, ctx);
                break;

        /* dst = -dst */
        case BPF_ALU | BPF_NEG:
        case BPF_ALU64 | BPF_NEG:
                emit(is64 ? rv_sub(rd, RV_REG_ZERO, rd) :
                     rv_subw(rd, RV_REG_ZERO, rd), ctx);
                if (!is64 && !aux->verifier_zext)
                        emit_zext_32(rd, ctx);
                break;

        /* dst = BSWAP##imm(dst) */
        case BPF_ALU | BPF_END | BPF_FROM_LE:
        {
                int shift = 64 - imm;

                emit(rv_slli(rd, rd, shift), ctx);
                emit(rv_srli(rd, rd, shift), ctx);
                break;
        }
        case BPF_ALU | BPF_END | BPF_FROM_BE:
                emit(rv_addi(RV_REG_T2, RV_REG_ZERO, 0), ctx);

                emit(rv_andi(RV_REG_T1, rd, 0xff), ctx);
                emit(rv_add(RV_REG_T2, RV_REG_T2, RV_REG_T1), ctx);
                emit(rv_slli(RV_REG_T2, RV_REG_T2, 8), ctx);
                emit(rv_srli(rd, rd, 8), ctx);
                if (imm == 16)
                        goto out_be;

                emit(rv_andi(RV_REG_T1, rd, 0xff), ctx);
                emit(rv_add(RV_REG_T2, RV_REG_T2, RV_REG_T1), ctx);
                emit(rv_slli(RV_REG_T2, RV_REG_T2, 8), ctx);
                emit(rv_srli(rd, rd, 8), ctx);

                emit(rv_andi(RV_REG_T1, rd, 0xff), ctx);
                emit(rv_add(RV_REG_T2, RV_REG_T2, RV_REG_T1), ctx);
                emit(rv_slli(RV_REG_T2, RV_REG_T2, 8), ctx);
                emit(rv_srli(rd, rd, 8), ctx);
                if (imm == 32)
                        goto out_be;

                emit(rv_andi(RV_REG_T1, rd, 0xff), ctx);
                emit(rv_add(RV_REG_T2, RV_REG_T2, RV_REG_T1), ctx);
                emit(rv_slli(RV_REG_T2, RV_REG_T2, 8), ctx);
                emit(rv_srli(rd, rd, 8), ctx);

                emit(rv_andi(RV_REG_T1, rd, 0xff), ctx);
                emit(rv_add(RV_REG_T2, RV_REG_T2, RV_REG_T1), ctx);
                emit(rv_slli(RV_REG_T2, RV_REG_T2, 8), ctx);
                emit(rv_srli(rd, rd, 8), ctx);

                emit(rv_andi(RV_REG_T1, rd, 0xff), ctx);
                emit(rv_add(RV_REG_T2, RV_REG_T2, RV_REG_T1), ctx);
                emit(rv_slli(RV_REG_T2, RV_REG_T2, 8), ctx);
                emit(rv_srli(rd, rd, 8), ctx);

                emit(rv_andi(RV_REG_T1, rd, 0xff), ctx);
                emit(rv_add(RV_REG_T2, RV_REG_T2, RV_REG_T1), ctx);
                emit(rv_slli(RV_REG_T2, RV_REG_T2, 8), ctx);
                emit(rv_srli(rd, rd, 8), ctx);
out_be:
                emit(rv_andi(RV_REG_T1, rd, 0xff), ctx);
                emit(rv_add(RV_REG_T2, RV_REG_T2, RV_REG_T1), ctx);

                emit(rv_addi(rd, RV_REG_T2, 0), ctx);
                break;

        /* dst = imm */
        case BPF_ALU | BPF_MOV | BPF_K:
        case BPF_ALU64 | BPF_MOV | BPF_K:
                emit_imm(rd, imm, ctx);
                if (!is64 && !aux->verifier_zext)
                        emit_zext_32(rd, ctx);
                break;

        /* dst = dst OP imm */
        case BPF_ALU | BPF_ADD | BPF_K:
        case BPF_ALU64 | BPF_ADD | BPF_K:
                if (is_12b_int(imm)) {
                        emit(is64 ? rv_addi(rd, rd, imm) :
                             rv_addiw(rd, rd, imm), ctx);
                } else {
                        emit_imm(RV_REG_T1, imm, ctx);
                        emit(is64 ? rv_add(rd, rd, RV_REG_T1) :
                             rv_addw(rd, rd, RV_REG_T1), ctx);
                }
                if (!is64 && !aux->verifier_zext)
                        emit_zext_32(rd, ctx);
                break;
        case BPF_ALU | BPF_SUB | BPF_K:
        case BPF_ALU64 | BPF_SUB | BPF_K:
                if (is_12b_int(-imm)) {
                        emit(is64 ? rv_addi(rd, rd, -imm) :
                             rv_addiw(rd, rd, -imm), ctx);
                } else {
                        emit_imm(RV_REG_T1, imm, ctx);
                        emit(is64 ? rv_sub(rd, rd, RV_REG_T1) :
                             rv_subw(rd, rd, RV_REG_T1), ctx);
                }
                if (!is64 && !aux->verifier_zext)
                        emit_zext_32(rd, ctx);
                break;
        case BPF_ALU | BPF_AND | BPF_K:
        case BPF_ALU64 | BPF_AND | BPF_K:
                if (is_12b_int(imm)) {
                        emit(rv_andi(rd, rd, imm), ctx);
                } else {
                        emit_imm(RV_REG_T1, imm, ctx);
                        emit(rv_and(rd, rd, RV_REG_T1), ctx);
                }
                if (!is64 && !aux->verifier_zext)
                        emit_zext_32(rd, ctx);
                break;
        case BPF_ALU | BPF_OR | BPF_K:
        case BPF_ALU64 | BPF_OR | BPF_K:
                if (is_12b_int(imm)) {
                        emit(rv_ori(rd, rd, imm), ctx);
                } else {
                        emit_imm(RV_REG_T1, imm, ctx);
                        emit(rv_or(rd, rd, RV_REG_T1), ctx);
                }
                if (!is64 && !aux->verifier_zext)
                        emit_zext_32(rd, ctx);
                break;
        case BPF_ALU | BPF_XOR | BPF_K:
        case BPF_ALU64 | BPF_XOR | BPF_K:
                if (is_12b_int(imm)) {
                        emit(rv_xori(rd, rd, imm), ctx);
                } else {
                        emit_imm(RV_REG_T1, imm, ctx);
                        emit(rv_xor(rd, rd, RV_REG_T1), ctx);
                }
                if (!is64 && !aux->verifier_zext)
                        emit_zext_32(rd, ctx);
                break;
        case BPF_ALU | BPF_MUL | BPF_K:
        case BPF_ALU64 | BPF_MUL | BPF_K:
                emit_imm(RV_REG_T1, imm, ctx);
                emit(is64 ? rv_mul(rd, rd, RV_REG_T1) :
                     rv_mulw(rd, rd, RV_REG_T1), ctx);
                if (!is64 && !aux->verifier_zext)
                        emit_zext_32(rd, ctx);
                break;
        case BPF_ALU | BPF_DIV | BPF_K:
        case BPF_ALU64 | BPF_DIV | BPF_K:
                emit_imm(RV_REG_T1, imm, ctx);
                emit(is64 ? rv_divu(rd, rd, RV_REG_T1) :
                     rv_divuw(rd, rd, RV_REG_T1), ctx);
                if (!is64 && !aux->verifier_zext)
                        emit_zext_32(rd, ctx);
                break;
        case BPF_ALU | BPF_MOD | BPF_K:
        case BPF_ALU64 | BPF_MOD | BPF_K:
                emit_imm(RV_REG_T1, imm, ctx);
                emit(is64 ? rv_remu(rd, rd, RV_REG_T1) :
                     rv_remuw(rd, rd, RV_REG_T1), ctx);
                if (!is64 && !aux->verifier_zext)
                        emit_zext_32(rd, ctx);
                break;
        case BPF_ALU | BPF_LSH | BPF_K:
        case BPF_ALU64 | BPF_LSH | BPF_K:
                emit(is64 ? rv_slli(rd, rd, imm) : rv_slliw(rd, rd, imm), ctx);
                if (!is64)
                        emit_zext_32(rd, ctx);
                break;
        case BPF_ALU | BPF_RSH | BPF_K:
        case BPF_ALU64 | BPF_RSH | BPF_K:
                emit(is64 ? rv_srli(rd, rd, imm) : rv_srliw(rd, rd, imm), ctx);
                if (!is64)
                        emit_zext_32(rd, ctx);
                break;
        case BPF_ALU | BPF_ARSH | BPF_K:
        case BPF_ALU64 | BPF_ARSH | BPF_K:
                emit(is64 ? rv_srai(rd, rd, imm) : rv_sraiw(rd, rd, imm), ctx);
                if (!is64)
                        emit_zext_32(rd, ctx);
                break;

        /* JUMP off */
        case BPF_JMP | BPF_JA:
                rvoff = rv_offset(i, off, ctx);
                emit_jump_and_link(RV_REG_ZERO, rvoff, false, ctx);
                break;

        /* IF (dst COND src) JUMP off */
        case BPF_JMP | BPF_JEQ | BPF_X:
        case BPF_JMP32 | BPF_JEQ | BPF_X:
        case BPF_JMP | BPF_JGT | BPF_X:
        case BPF_JMP32 | BPF_JGT | BPF_X:
        case BPF_JMP | BPF_JLT | BPF_X:
        case BPF_JMP32 | BPF_JLT | BPF_X:
        case BPF_JMP | BPF_JGE | BPF_X:
        case BPF_JMP32 | BPF_JGE | BPF_X:
        case BPF_JMP | BPF_JLE | BPF_X:
        case BPF_JMP32 | BPF_JLE | BPF_X:
        case BPF_JMP | BPF_JNE | BPF_X:
        case BPF_JMP32 | BPF_JNE | BPF_X:
        case BPF_JMP | BPF_JSGT | BPF_X:
        case BPF_JMP32 | BPF_JSGT | BPF_X:
        case BPF_JMP | BPF_JSLT | BPF_X:
        case BPF_JMP32 | BPF_JSLT | BPF_X:
        case BPF_JMP | BPF_JSGE | BPF_X:
        case BPF_JMP32 | BPF_JSGE | BPF_X:
        case BPF_JMP | BPF_JSLE | BPF_X:
        case BPF_JMP32 | BPF_JSLE | BPF_X:
        case BPF_JMP | BPF_JSET | BPF_X:
        case BPF_JMP32 | BPF_JSET | BPF_X:
                rvoff = rv_offset(i, off, ctx);
                if (!is64) {
                        s = ctx->ninsns;
                        if (is_signed_bpf_cond(BPF_OP(code)))
                                emit_sext_32_rd_rs(&rd, &rs, ctx);
                        else
                                emit_zext_32_rd_rs(&rd, &rs, ctx);
                        e = ctx->ninsns;

                        /* Adjust for extra insns */
                        rvoff -= (e - s) << 2;
                }

                if (BPF_OP(code) == BPF_JSET) {
                        /* Adjust for and */
                        rvoff -= 4;
                        emit(rv_and(RV_REG_T1, rd, rs), ctx);
                        emit_branch(BPF_JNE, RV_REG_T1, RV_REG_ZERO, rvoff,
                                    ctx);
                } else {
                        emit_branch(BPF_OP(code), rd, rs, rvoff, ctx);
                }
                break;

        /* IF (dst COND imm) JUMP off */
        case BPF_JMP | BPF_JEQ | BPF_K:
        case BPF_JMP32 | BPF_JEQ | BPF_K:
        case BPF_JMP | BPF_JGT | BPF_K:
        case BPF_JMP32 | BPF_JGT | BPF_K:
        case BPF_JMP | BPF_JLT | BPF_K:
        case BPF_JMP32 | BPF_JLT | BPF_K:
        case BPF_JMP | BPF_JGE | BPF_K:
        case BPF_JMP32 | BPF_JGE | BPF_K:
        case BPF_JMP | BPF_JLE | BPF_K:
        case BPF_JMP32 | BPF_JLE | BPF_K:
        case BPF_JMP | BPF_JNE | BPF_K:
        case BPF_JMP32 | BPF_JNE | BPF_K:
        case BPF_JMP | BPF_JSGT | BPF_K:
        case BPF_JMP32 | BPF_JSGT | BPF_K:
        case BPF_JMP | BPF_JSLT | BPF_K:
        case BPF_JMP32 | BPF_JSLT | BPF_K:
        case BPF_JMP | BPF_JSGE | BPF_K:
        case BPF_JMP32 | BPF_JSGE | BPF_K:
        case BPF_JMP | BPF_JSLE | BPF_K:
        case BPF_JMP32 | BPF_JSLE | BPF_K:
        case BPF_JMP | BPF_JSET | BPF_K:
        case BPF_JMP32 | BPF_JSET | BPF_K:
                rvoff = rv_offset(i, off, ctx);
                s = ctx->ninsns;
                emit_imm(RV_REG_T1, imm, ctx);
                if (!is64) {
                        if (is_signed_bpf_cond(BPF_OP(code)))
                                emit_sext_32_rd(&rd, ctx);
                        else
                                emit_zext_32_rd_t1(&rd, ctx);
                }
                e = ctx->ninsns;

                /* Adjust for extra insns */
                rvoff -= (e - s) << 2;

                if (BPF_OP(code) == BPF_JSET) {
                        /* Adjust for and */
                        rvoff -= 4;
                        emit(rv_and(RV_REG_T1, rd, RV_REG_T1), ctx);
                        emit_branch(BPF_JNE, RV_REG_T1, RV_REG_ZERO, rvoff,
                                    ctx);
                } else {
                        emit_branch(BPF_OP(code), rd, RV_REG_T1, rvoff, ctx);
                }
                break;

        /* function call */
        case BPF_JMP | BPF_CALL:
        {
                bool fixed;
                int ret;
                u64 addr;

                mark_call(ctx);
                ret = bpf_jit_get_func_addr(ctx->prog, insn, extra_pass, &addr,
                                            &fixed);
                if (ret < 0)
                        return ret;
                ret = emit_call(fixed, addr, ctx);
                if (ret)
                        return ret;
                break;
        }
        /* tail call */
        case BPF_JMP | BPF_TAIL_CALL:
                if (emit_bpf_tail_call(i, ctx))
                        return -1;
                break;

        /* function return */
        case BPF_JMP | BPF_EXIT:
                if (i == ctx->prog->len - 1)
                        break;

                rvoff = epilogue_offset(ctx);
                emit_jump_and_link(RV_REG_ZERO, rvoff, false, ctx);
                break;

        /* dst = imm64 */
        case BPF_LD | BPF_IMM | BPF_DW:
        {
                struct bpf_insn insn1 = insn[1];
                u64 imm64;

                imm64 = (u64)insn1.imm << 32 | (u32)imm;
                emit_imm(rd, imm64, ctx);
                return 1;
        }

        /* LDX: dst = *(size *)(src + off) */
        case BPF_LDX | BPF_MEM | BPF_B:
                if (is_12b_int(off)) {
                        emit(rv_lbu(rd, off, rs), ctx);
                        break;
                }

                emit_imm(RV_REG_T1, off, ctx);
                emit(rv_add(RV_REG_T1, RV_REG_T1, rs), ctx);
                emit(rv_lbu(rd, 0, RV_REG_T1), ctx);
                if (insn_is_zext(&insn[1]))
                        return 1;
                break;
        case BPF_LDX | BPF_MEM | BPF_H:
                if (is_12b_int(off)) {
                        emit(rv_lhu(rd, off, rs), ctx);
                        break;
                }

                emit_imm(RV_REG_T1, off, ctx);
                emit(rv_add(RV_REG_T1, RV_REG_T1, rs), ctx);
                emit(rv_lhu(rd, 0, RV_REG_T1), ctx);
                if (insn_is_zext(&insn[1]))
                        return 1;
                break;
        case BPF_LDX | BPF_MEM | BPF_W:
                if (is_12b_int(off)) {
                        emit(rv_lwu(rd, off, rs), ctx);
                        break;
                }

                emit_imm(RV_REG_T1, off, ctx);
                emit(rv_add(RV_REG_T1, RV_REG_T1, rs), ctx);
                emit(rv_lwu(rd, 0, RV_REG_T1), ctx);
                if (insn_is_zext(&insn[1]))
                        return 1;
                break;
        case BPF_LDX | BPF_MEM | BPF_DW:
                if (is_12b_int(off)) {
                        emit(rv_ld(rd, off, rs), ctx);
                        break;
                }

                emit_imm(RV_REG_T1, off, ctx);
                emit(rv_add(RV_REG_T1, RV_REG_T1, rs), ctx);
                emit(rv_ld(rd, 0, RV_REG_T1), ctx);
                break;

        /* ST: *(size *)(dst + off) = imm */
        case BPF_ST | BPF_MEM | BPF_B:
                emit_imm(RV_REG_T1, imm, ctx);
                if (is_12b_int(off)) {
                        emit(rv_sb(rd, off, RV_REG_T1), ctx);
                        break;
                }

                emit_imm(RV_REG_T2, off, ctx);
                emit(rv_add(RV_REG_T2, RV_REG_T2, rd), ctx);
                emit(rv_sb(RV_REG_T2, 0, RV_REG_T1), ctx);
                break;

        case BPF_ST | BPF_MEM | BPF_H:
                emit_imm(RV_REG_T1, imm, ctx);
                if (is_12b_int(off)) {
                        emit(rv_sh(rd, off, RV_REG_T1), ctx);
                        break;
                }

                emit_imm(RV_REG_T2, off, ctx);
                emit(rv_add(RV_REG_T2, RV_REG_T2, rd), ctx);
                emit(rv_sh(RV_REG_T2, 0, RV_REG_T1), ctx);
                break;
        case BPF_ST | BPF_MEM | BPF_W:
                emit_imm(RV_REG_T1, imm, ctx);
                if (is_12b_int(off)) {
                        emit(rv_sw(rd, off, RV_REG_T1), ctx);
                        break;
                }

                emit_imm(RV_REG_T2, off, ctx);
                emit(rv_add(RV_REG_T2, RV_REG_T2, rd), ctx);
                emit(rv_sw(RV_REG_T2, 0, RV_REG_T1), ctx);
                break;
        case BPF_ST | BPF_MEM | BPF_DW:
                emit_imm(RV_REG_T1, imm, ctx);
                if (is_12b_int(off)) {
                        emit(rv_sd(rd, off, RV_REG_T1), ctx);
                        break;
                }

                emit_imm(RV_REG_T2, off, ctx);
                emit(rv_add(RV_REG_T2, RV_REG_T2, rd), ctx);
                emit(rv_sd(RV_REG_T2, 0, RV_REG_T1), ctx);
                break;

        /* STX: *(size *)(dst + off) = src */
        case BPF_STX | BPF_MEM | BPF_B:
                if (is_12b_int(off)) {
                        emit(rv_sb(rd, off, rs), ctx);
                        break;
                }

                emit_imm(RV_REG_T1, off, ctx);
                emit(rv_add(RV_REG_T1, RV_REG_T1, rd), ctx);
                emit(rv_sb(RV_REG_T1, 0, rs), ctx);
                break;
        case BPF_STX | BPF_MEM | BPF_H:
                if (is_12b_int(off)) {
                        emit(rv_sh(rd, off, rs), ctx);
                        break;
                }

                emit_imm(RV_REG_T1, off, ctx);
                emit(rv_add(RV_REG_T1, RV_REG_T1, rd), ctx);
                emit(rv_sh(RV_REG_T1, 0, rs), ctx);
                break;
        case BPF_STX | BPF_MEM | BPF_W:
                if (is_12b_int(off)) {
                        emit(rv_sw(rd, off, rs), ctx);
                        break;
                }

                emit_imm(RV_REG_T1, off, ctx);
                emit(rv_add(RV_REG_T1, RV_REG_T1, rd), ctx);
                emit(rv_sw(RV_REG_T1, 0, rs), ctx);
                break;
        case BPF_STX | BPF_MEM | BPF_DW:
                if (is_12b_int(off)) {
                        emit(rv_sd(rd, off, rs), ctx);
                        break;
                }

                emit_imm(RV_REG_T1, off, ctx);
                emit(rv_add(RV_REG_T1, RV_REG_T1, rd), ctx);
                emit(rv_sd(RV_REG_T1, 0, rs), ctx);
                break;
        /* STX XADD: lock *(u32 *)(dst + off) += src */
        case BPF_STX | BPF_XADD | BPF_W:
        /* STX XADD: lock *(u64 *)(dst + off) += src */
        case BPF_STX | BPF_XADD | BPF_DW:
                if (off) {
                        if (is_12b_int(off)) {
                                emit(rv_addi(RV_REG_T1, rd, off), ctx);
                        } else {
                                emit_imm(RV_REG_T1, off, ctx);
                                emit(rv_add(RV_REG_T1, RV_REG_T1, rd), ctx);
                        }

                        rd = RV_REG_T1;
                }

                emit(BPF_SIZE(code) == BPF_W ?
                     rv_amoadd_w(RV_REG_ZERO, rs, rd, 0, 0) :
                     rv_amoadd_d(RV_REG_ZERO, rs, rd, 0, 0), ctx);
                break;
        default:
                pr_err("bpf-jit: unknown opcode %02x\n", code);
                return -EINVAL;
        }

        return 0;
}

static void build_prologue(struct rv_jit_context *ctx)
{
        int stack_adjust = 0, store_offset, bpf_stack_adjust;

        bpf_stack_adjust = round_up(ctx->prog->aux->stack_depth, 16);
        if (bpf_stack_adjust)
                mark_fp(ctx);

        if (seen_reg(RV_REG_RA, ctx))
                stack_adjust += 8;
        stack_adjust += 8; /* RV_REG_FP */
        if (seen_reg(RV_REG_S1, ctx))
                stack_adjust += 8;
        if (seen_reg(RV_REG_S2, ctx))
                stack_adjust += 8;
        if (seen_reg(RV_REG_S3, ctx))
                stack_adjust += 8;
        if (seen_reg(RV_REG_S4, ctx))
                stack_adjust += 8;
        if (seen_reg(RV_REG_S5, ctx))
                stack_adjust += 8;
        if (seen_reg(RV_REG_S6, ctx))
                stack_adjust += 8;

        stack_adjust = round_up(stack_adjust, 16);
        stack_adjust += bpf_stack_adjust;

        store_offset = stack_adjust - 8;

        /* First instruction is always setting the tail-call-counter
         * (TCC) register. This instruction is skipped for tail calls.
         */
        emit(rv_addi(RV_REG_TCC, RV_REG_ZERO, MAX_TAIL_CALL_CNT), ctx);

        emit(rv_addi(RV_REG_SP, RV_REG_SP, -stack_adjust), ctx);

        if (seen_reg(RV_REG_RA, ctx)) {
                emit(rv_sd(RV_REG_SP, store_offset, RV_REG_RA), ctx);
                store_offset -= 8;
        }
        emit(rv_sd(RV_REG_SP, store_offset, RV_REG_FP), ctx);
        store_offset -= 8;
        if (seen_reg(RV_REG_S1, ctx)) {
                emit(rv_sd(RV_REG_SP, store_offset, RV_REG_S1), ctx);
                store_offset -= 8;
        }
        if (seen_reg(RV_REG_S2, ctx)) {
                emit(rv_sd(RV_REG_SP, store_offset, RV_REG_S2), ctx);
                store_offset -= 8;
        }
        if (seen_reg(RV_REG_S3, ctx)) {
                emit(rv_sd(RV_REG_SP, store_offset, RV_REG_S3), ctx);
                store_offset -= 8;
        }
        if (seen_reg(RV_REG_S4, ctx)) {
                emit(rv_sd(RV_REG_SP, store_offset, RV_REG_S4), ctx);
                store_offset -= 8;
        }
        if (seen_reg(RV_REG_S5, ctx)) {
                emit(rv_sd(RV_REG_SP, store_offset, RV_REG_S5), ctx);
                store_offset -= 8;
        }
        if (seen_reg(RV_REG_S6, ctx)) {
                emit(rv_sd(RV_REG_SP, store_offset, RV_REG_S6), ctx);
                store_offset -= 8;
        }

        emit(rv_addi(RV_REG_FP, RV_REG_SP, stack_adjust), ctx);

        if (bpf_stack_adjust)
                emit(rv_addi(RV_REG_S5, RV_REG_SP, bpf_stack_adjust), ctx);

        /* Program contains calls and tail calls, so RV_REG_TCC need
         * to be saved across calls.
         */
        if (seen_tail_call(ctx) && seen_call(ctx))
                emit(rv_addi(RV_REG_TCC_SAVED, RV_REG_TCC, 0), ctx);

        ctx->stack_size = stack_adjust;
}

static void build_epilogue(struct rv_jit_context *ctx)
{
        __build_epilogue(false, ctx);
}

static int build_body(struct rv_jit_context *ctx, bool extra_pass, int *offset)
{
        const struct bpf_prog *prog = ctx->prog;
        int i;

        for (i = 0; i < prog->len; i++) {
                const struct bpf_insn *insn = &prog->insnsi[i];
                int ret;

                ret = emit_insn(insn, ctx, extra_pass);
                if (ret > 0) {
                        i++;
                        if (offset)
                                offset[i] = ctx->ninsns;
                        continue;
                }
                if (offset)
                        offset[i] = ctx->ninsns;
                if (ret)
                        return ret;
        }
        return 0;
}

static void bpf_fill_ill_insns(void *area, unsigned int size)
{
        memset(area, 0, size);
}

static void bpf_flush_icache(void *start, void *end)
{
        flush_icache_range((unsigned long)start, (unsigned long)end);
}

bool bpf_jit_needs_zext(void)
{
        return true;
}

struct bpf_prog *bpf_int_jit_compile(struct bpf_prog *prog)
{
        bool tmp_blinded = false, extra_pass = false;
        struct bpf_prog *tmp, *orig_prog = prog;
        int pass = 0, prev_ninsns = 0, i;
        struct rv_jit_data *jit_data;
        unsigned int image_size = 0;
        struct rv_jit_context *ctx;

        if (!prog->jit_requested)
                return orig_prog;

        tmp = bpf_jit_blind_constants(prog);
        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;
        }

        ctx = &jit_data->ctx;

        if (ctx->offset) {
                extra_pass = true;
                image_size = sizeof(u32) * ctx->ninsns;
                goto skip_init_ctx;
        }

        ctx->prog = prog;
        ctx->offset = kcalloc(prog->len, sizeof(int), GFP_KERNEL);
        if (!ctx->offset) {
                prog = orig_prog;
                goto out_offset;
        }
        for (i = 0; i < prog->len; i++) {
                prev_ninsns += 32;
                ctx->offset[i] = prev_ninsns;
        }

        for (i = 0; i < 16; i++) {
                pass++;
                ctx->ninsns = 0;
                if (build_body(ctx, extra_pass, ctx->offset)) {
                        prog = orig_prog;
                        goto out_offset;
                }
                build_prologue(ctx);
                ctx->epilogue_offset = ctx->ninsns;
                build_epilogue(ctx);

                if (ctx->ninsns == prev_ninsns) {
                        if (jit_data->header)
                                break;

                        image_size = sizeof(u32) * ctx->ninsns;
                        jit_data->header =
                                bpf_jit_binary_alloc(image_size,
                                                     &jit_data->image,
                                                     sizeof(u32),
                                                     bpf_fill_ill_insns);
                        if (!jit_data->header) {
                                prog = orig_prog;
                                goto out_offset;
                        }

                        ctx->insns = (u32 *)jit_data->image;
                        /* Now, when the image is allocated, the image
                         * can potentially shrink more (auipc/jalr ->
                         * jal).
                         */
                }
                prev_ninsns = ctx->ninsns;
        }

        if (i == 16) {
                pr_err("bpf-jit: image did not converge in <%d passes!\n", i);
                bpf_jit_binary_free(jit_data->header);
                prog = orig_prog;
                goto out_offset;
        }

skip_init_ctx:
        pass++;
        ctx->ninsns = 0;

        build_prologue(ctx);
        if (build_body(ctx, extra_pass, NULL)) {
                bpf_jit_binary_free(jit_data->header);
                prog = orig_prog;
                goto out_offset;
        }
        build_epilogue(ctx);

        if (bpf_jit_enable > 1)
                bpf_jit_dump(prog->len, image_size, pass, ctx->insns);

        prog->bpf_func = (void *)ctx->insns;
        prog->jited = 1;
        prog->jited_len = image_size;

        bpf_flush_icache(jit_data->header, ctx->insns + ctx->ninsns);

        if (!prog->is_func || extra_pass) {
out_offset:
                kfree(ctx->offset);
                kfree(jit_data);
                prog->aux->jit_data = NULL;
        }
out:
        if (tmp_blinded)
                bpf_jit_prog_release_other(prog, prog == orig_prog ?
                                           tmp : orig_prog);
        return prog;
}

void *bpf_jit_alloc_exec(unsigned long size)
{
        return __vmalloc_node_range(size, PAGE_SIZE, BPF_JIT_REGION_START,
                                    BPF_JIT_REGION_END, GFP_KERNEL,
                                    PAGE_KERNEL_EXEC, 0, NUMA_NO_NODE,
                                    __builtin_return_address(0));
}

void bpf_jit_free_exec(void *addr)
{
        return vfree(addr);
}