// SPDX-License-Identifier: GPL-2.0-only
/*
 * eBPF JIT compiler for PPC32
 *
 * Copyright 2020 Christophe Leroy <christophe.leroy@csgroup.eu>
 *                CS GROUP France
 *
 * Based on PPC64 eBPF JIT compiler by Naveen N. Rao
 */
#include <linux/moduleloader.h>
#include <asm/cacheflush.h>
#include <asm/asm-compat.h>
#include <linux/netdevice.h>
#include <linux/filter.h>
#include <linux/if_vlan.h>
#include <asm/kprobes.h>
#include <linux/bpf.h>

#include "bpf_jit.h"

/*
 * Stack layout:
 *
 *              [       prev sp         ] <-------------
 *              [   nv gpr save area    ] 16 * 4        |
 * fp (r31) --> [   ebpf stack space    ] upto 512      |
 *              [     frame header      ] 16            |
 * sp (r1) ---> [    stack pointer      ] --------------
 */

/* for gpr non volatile registers r17 to r31 (14) + tail call */
#define BPF_PPC_STACK_SAVE      (15 * 4 + 4)
/* stack frame, ensure this is quadword aligned */
#define BPF_PPC_STACKFRAME(ctx) (STACK_FRAME_MIN_SIZE + BPF_PPC_STACK_SAVE + (ctx)->stack_size)

#define PPC_EX32(r, i)          EMIT(PPC_RAW_LI((r), (i) < 0 ? -1 : 0))

/* PPC NVR range -- update this if we ever use NVRs below r17 */
#define BPF_PPC_NVR_MIN         _R17
#define BPF_PPC_TC              _R16

/* BPF register usage */
#define TMP_REG                 (MAX_BPF_JIT_REG + 0)

/* BPF to ppc register mappings */
void bpf_jit_init_reg_mapping(struct codegen_context *ctx)
{
        /* function return value */
        ctx->b2p[BPF_REG_0] = _R12;
        /* function arguments */
        ctx->b2p[BPF_REG_1] = _R4;
        ctx->b2p[BPF_REG_2] = _R6;
        ctx->b2p[BPF_REG_3] = _R8;
        ctx->b2p[BPF_REG_4] = _R10;
        ctx->b2p[BPF_REG_5] = _R22;
        /* non volatile registers */
        ctx->b2p[BPF_REG_6] = _R24;
        ctx->b2p[BPF_REG_7] = _R26;
        ctx->b2p[BPF_REG_8] = _R28;
        ctx->b2p[BPF_REG_9] = _R30;
        /* frame pointer aka BPF_REG_10 */
        ctx->b2p[BPF_REG_FP] = _R18;
        /* eBPF jit internal registers */
        ctx->b2p[BPF_REG_AX] = _R20;
        ctx->b2p[TMP_REG] = _R31;               /* 32 bits */
}

static int bpf_jit_stack_offsetof(struct codegen_context *ctx, int reg)
{
        if ((reg >= BPF_PPC_NVR_MIN && reg < 32) || reg == BPF_PPC_TC)
                return BPF_PPC_STACKFRAME(ctx) - 4 * (32 - reg);

        WARN(true, "BPF JIT is asking about unknown registers, will crash the stack");
        /* Use the hole we have left for alignment */
        return BPF_PPC_STACKFRAME(ctx) - 4;
}

#define SEEN_VREG_MASK          0x1ff80000 /* Volatile registers r3-r12 */
#define SEEN_NVREG_FULL_MASK    0x0003ffff /* Non volatile registers r14-r31 */
#define SEEN_NVREG_TEMP_MASK    0x00001e01 /* BPF_REG_5, BPF_REG_AX, TMP_REG */

void bpf_jit_realloc_regs(struct codegen_context *ctx)
{
        unsigned int nvreg_mask;

        if (ctx->seen & SEEN_FUNC)
                nvreg_mask = SEEN_NVREG_TEMP_MASK;
        else
                nvreg_mask = SEEN_NVREG_FULL_MASK;

        while (ctx->seen & nvreg_mask &&
              (ctx->seen & SEEN_VREG_MASK) != SEEN_VREG_MASK) {
                int old = 32 - fls(ctx->seen & (nvreg_mask & 0xaaaaaaab));
                int new = 32 - fls(~ctx->seen & (SEEN_VREG_MASK & 0xaaaaaaaa));
                int i;

                for (i = BPF_REG_0; i <= TMP_REG; i++) {
                        if (ctx->b2p[i] != old)
                                continue;
                        ctx->b2p[i] = new;
                        bpf_set_seen_register(ctx, new);
                        bpf_clear_seen_register(ctx, old);
                        if (i != TMP_REG) {
                                bpf_set_seen_register(ctx, new - 1);
                                bpf_clear_seen_register(ctx, old - 1);
                        }
                        break;
                }
        }
}

void bpf_jit_build_prologue(u32 *image, struct codegen_context *ctx)
{
        int i;

        /* First arg comes in as a 32 bits pointer. */
        EMIT(PPC_RAW_MR(bpf_to_ppc(BPF_REG_1), _R3));
        EMIT(PPC_RAW_LI(bpf_to_ppc(BPF_REG_1) - 1, 0));
        EMIT(PPC_RAW_STWU(_R1, _R1, -BPF_PPC_STACKFRAME(ctx)));

        /*
         * Initialize tail_call_cnt in stack frame if we do tail calls.
         * Otherwise, put in NOPs so that it can be skipped when we are
         * invoked through a tail call.
         */
        if (ctx->seen & SEEN_TAILCALL)
                EMIT(PPC_RAW_STW(bpf_to_ppc(BPF_REG_1) - 1, _R1,
                                 bpf_jit_stack_offsetof(ctx, BPF_PPC_TC)));
        else
                EMIT(PPC_RAW_NOP());

#define BPF_TAILCALL_PROLOGUE_SIZE      16

        /*
         * We need a stack frame, but we don't necessarily need to
         * save/restore LR unless we call other functions
         */
        if (ctx->seen & SEEN_FUNC)
                EMIT(PPC_RAW_MFLR(_R0));

        /*
         * Back up non-volatile regs -- registers r18-r31
         */
        for (i = BPF_PPC_NVR_MIN; i <= 31; i++)
                if (bpf_is_seen_register(ctx, i))
                        EMIT(PPC_RAW_STW(i, _R1, bpf_jit_stack_offsetof(ctx, i)));

        /* If needed retrieve arguments 9 and 10, ie 5th 64 bits arg.*/
        if (bpf_is_seen_register(ctx, bpf_to_ppc(BPF_REG_5))) {
                EMIT(PPC_RAW_LWZ(bpf_to_ppc(BPF_REG_5) - 1, _R1, BPF_PPC_STACKFRAME(ctx)) + 8);
                EMIT(PPC_RAW_LWZ(bpf_to_ppc(BPF_REG_5), _R1, BPF_PPC_STACKFRAME(ctx)) + 12);
        }

        /* Setup frame pointer to point to the bpf stack area */
        if (bpf_is_seen_register(ctx, bpf_to_ppc(BPF_REG_FP))) {
                EMIT(PPC_RAW_LI(bpf_to_ppc(BPF_REG_FP) - 1, 0));
                EMIT(PPC_RAW_ADDI(bpf_to_ppc(BPF_REG_FP), _R1,
                                  STACK_FRAME_MIN_SIZE + ctx->stack_size));
        }

        if (ctx->seen & SEEN_FUNC)
                EMIT(PPC_RAW_STW(_R0, _R1, BPF_PPC_STACKFRAME(ctx) + PPC_LR_STKOFF));
}

static void bpf_jit_emit_common_epilogue(u32 *image, struct codegen_context *ctx)
{
        int i;

        /* Restore NVRs */
        for (i = BPF_PPC_NVR_MIN; i <= 31; i++)
                if (bpf_is_seen_register(ctx, i))
                        EMIT(PPC_RAW_LWZ(i, _R1, bpf_jit_stack_offsetof(ctx, i)));
}

void bpf_jit_build_epilogue(u32 *image, struct codegen_context *ctx)
{
        EMIT(PPC_RAW_MR(_R3, bpf_to_ppc(BPF_REG_0)));

        bpf_jit_emit_common_epilogue(image, ctx);

        /* Tear down our stack frame */

        if (ctx->seen & SEEN_FUNC)
                EMIT(PPC_RAW_LWZ(_R0, _R1, BPF_PPC_STACKFRAME(ctx) + PPC_LR_STKOFF));

        EMIT(PPC_RAW_ADDI(_R1, _R1, BPF_PPC_STACKFRAME(ctx)));

        if (ctx->seen & SEEN_FUNC)
                EMIT(PPC_RAW_MTLR(_R0));

        EMIT(PPC_RAW_BLR());
}

int bpf_jit_emit_func_call_rel(u32 *image, struct codegen_context *ctx, u64 func)
{
        s32 rel = (s32)func - (s32)(image + ctx->idx);

        if (image && rel < 0x2000000 && rel >= -0x2000000) {
                PPC_BL(func);
                EMIT(PPC_RAW_NOP());
                EMIT(PPC_RAW_NOP());
                EMIT(PPC_RAW_NOP());
        } else {
                /* Load function address into r0 */
                EMIT(PPC_RAW_LIS(_R0, IMM_H(func)));
                EMIT(PPC_RAW_ORI(_R0, _R0, IMM_L(func)));
                EMIT(PPC_RAW_MTCTR(_R0));
                EMIT(PPC_RAW_BCTRL());
        }

        return 0;
}

static int bpf_jit_emit_tail_call(u32 *image, struct codegen_context *ctx, u32 out)
{
        /*
         * By now, the eBPF program has already setup parameters in r3-r6
         * r3-r4/BPF_REG_1 - pointer to ctx -- passed as is to the next bpf program
         * r5-r6/BPF_REG_2 - pointer to bpf_array
         * r7-r8/BPF_REG_3 - index in bpf_array
         */
        int b2p_bpf_array = bpf_to_ppc(BPF_REG_2);
        int b2p_index = bpf_to_ppc(BPF_REG_3);

        /*
         * if (index >= array->map.max_entries)
         *   goto out;
         */
        EMIT(PPC_RAW_LWZ(_R0, b2p_bpf_array, offsetof(struct bpf_array, map.max_entries)));
        EMIT(PPC_RAW_CMPLW(b2p_index, _R0));
        EMIT(PPC_RAW_LWZ(_R0, _R1, bpf_jit_stack_offsetof(ctx, BPF_PPC_TC)));
        PPC_BCC_SHORT(COND_GE, out);

        /*
         * if (tail_call_cnt >= MAX_TAIL_CALL_CNT)
         *   goto out;
         */
        EMIT(PPC_RAW_CMPLWI(_R0, MAX_TAIL_CALL_CNT));
        /* tail_call_cnt++; */
        EMIT(PPC_RAW_ADDIC(_R0, _R0, 1));
        PPC_BCC_SHORT(COND_GE, out);

        /* prog = array->ptrs[index]; */
        EMIT(PPC_RAW_RLWINM(_R3, b2p_index, 2, 0, 29));
        EMIT(PPC_RAW_ADD(_R3, _R3, b2p_bpf_array));
        EMIT(PPC_RAW_LWZ(_R3, _R3, offsetof(struct bpf_array, ptrs)));
        EMIT(PPC_RAW_STW(_R0, _R1, bpf_jit_stack_offsetof(ctx, BPF_PPC_TC)));

        /*
         * if (prog == NULL)
         *   goto out;
         */
        EMIT(PPC_RAW_CMPLWI(_R3, 0));
        PPC_BCC_SHORT(COND_EQ, out);

        /* goto *(prog->bpf_func + prologue_size); */
        EMIT(PPC_RAW_LWZ(_R3, _R3, offsetof(struct bpf_prog, bpf_func)));

        if (ctx->seen & SEEN_FUNC)
                EMIT(PPC_RAW_LWZ(_R0, _R1, BPF_PPC_STACKFRAME(ctx) + PPC_LR_STKOFF));

        EMIT(PPC_RAW_ADDIC(_R3, _R3, BPF_TAILCALL_PROLOGUE_SIZE));

        if (ctx->seen & SEEN_FUNC)
                EMIT(PPC_RAW_MTLR(_R0));

        EMIT(PPC_RAW_MTCTR(_R3));

        EMIT(PPC_RAW_MR(_R3, bpf_to_ppc(BPF_REG_1)));

        /* tear restore NVRs, ... */
        bpf_jit_emit_common_epilogue(image, ctx);

        EMIT(PPC_RAW_BCTR());

        /* out: */
        return 0;
}

/* Assemble the body code between the prologue & epilogue */
int bpf_jit_build_body(struct bpf_prog *fp, u32 *image, struct codegen_context *ctx,
                       u32 *addrs, int pass)
{
        const struct bpf_insn *insn = fp->insnsi;
        int flen = fp->len;
        int i, ret;

        /* Start of epilogue code - will only be valid 2nd pass onwards */
        u32 exit_addr = addrs[flen];

        for (i = 0; i < flen; i++) {
                u32 code = insn[i].code;
                u32 dst_reg = bpf_to_ppc(insn[i].dst_reg);
                u32 dst_reg_h = dst_reg - 1;
                u32 src_reg = bpf_to_ppc(insn[i].src_reg);
                u32 src_reg_h = src_reg - 1;
                u32 tmp_reg = bpf_to_ppc(TMP_REG);
                u32 size = BPF_SIZE(code);
                s16 off = insn[i].off;
                s32 imm = insn[i].imm;
                bool func_addr_fixed;
                u64 func_addr;
                u32 true_cond;
                u32 tmp_idx;
                int j;

                /*
                 * addrs[] maps a BPF bytecode address into a real offset from
                 * the start of the body code.
                 */
                addrs[i] = ctx->idx * 4;

                /*
                 * As an optimization, we note down which registers
                 * are used so that we can only save/restore those in our
                 * prologue and epilogue. We do this here regardless of whether
                 * the actual BPF instruction uses src/dst registers or not
                 * (for instance, BPF_CALL does not use them). The expectation
                 * is that those instructions will have src_reg/dst_reg set to
                 * 0. Even otherwise, we just lose some prologue/epilogue
                 * optimization but everything else should work without
                 * any issues.
                 */
                if (dst_reg >= 3 && dst_reg < 32) {
                        bpf_set_seen_register(ctx, dst_reg);
                        bpf_set_seen_register(ctx, dst_reg_h);
                }

                if (src_reg >= 3 && src_reg < 32) {
                        bpf_set_seen_register(ctx, src_reg);
                        bpf_set_seen_register(ctx, src_reg_h);
                }

                switch (code) {
                /*
                 * Arithmetic operations: ADD/SUB/MUL/DIV/MOD/NEG
                 */
                case BPF_ALU | BPF_ADD | BPF_X: /* (u32) dst += (u32) src */
                        EMIT(PPC_RAW_ADD(dst_reg, dst_reg, src_reg));
                        break;
                case BPF_ALU64 | BPF_ADD | BPF_X: /* dst += src */
                        EMIT(PPC_RAW_ADDC(dst_reg, dst_reg, src_reg));
                        EMIT(PPC_RAW_ADDE(dst_reg_h, dst_reg_h, src_reg_h));
                        break;
                case BPF_ALU | BPF_SUB | BPF_X: /* (u32) dst -= (u32) src */
                        EMIT(PPC_RAW_SUB(dst_reg, dst_reg, src_reg));
                        break;
                case BPF_ALU64 | BPF_SUB | BPF_X: /* dst -= src */
                        EMIT(PPC_RAW_SUBFC(dst_reg, src_reg, dst_reg));
                        EMIT(PPC_RAW_SUBFE(dst_reg_h, src_reg_h, dst_reg_h));
                        break;
                case BPF_ALU | BPF_SUB | BPF_K: /* (u32) dst -= (u32) imm */
                        imm = -imm;
                        fallthrough;
                case BPF_ALU | BPF_ADD | BPF_K: /* (u32) dst += (u32) imm */
                        if (IMM_HA(imm) & 0xffff)
                                EMIT(PPC_RAW_ADDIS(dst_reg, dst_reg, IMM_HA(imm)));
                        if (IMM_L(imm))
                                EMIT(PPC_RAW_ADDI(dst_reg, dst_reg, IMM_L(imm)));
                        break;
                case BPF_ALU64 | BPF_SUB | BPF_K: /* dst -= imm */
                        imm = -imm;
                        fallthrough;
                case BPF_ALU64 | BPF_ADD | BPF_K: /* dst += imm */
                        if (!imm)
                                break;

                        if (imm >= -32768 && imm < 32768) {
                                EMIT(PPC_RAW_ADDIC(dst_reg, dst_reg, imm));
                        } else {
                                PPC_LI32(_R0, imm);
                                EMIT(PPC_RAW_ADDC(dst_reg, dst_reg, _R0));
                        }
                        if (imm >= 0 || (BPF_OP(code) == BPF_SUB && imm == 0x80000000))
                                EMIT(PPC_RAW_ADDZE(dst_reg_h, dst_reg_h));
                        else
                                EMIT(PPC_RAW_ADDME(dst_reg_h, dst_reg_h));
                        break;
                case BPF_ALU64 | BPF_MUL | BPF_X: /* dst *= src */
                        bpf_set_seen_register(ctx, tmp_reg);
                        EMIT(PPC_RAW_MULW(_R0, dst_reg, src_reg_h));
                        EMIT(PPC_RAW_MULW(dst_reg_h, dst_reg_h, src_reg));
                        EMIT(PPC_RAW_MULHWU(tmp_reg, dst_reg, src_reg));
                        EMIT(PPC_RAW_MULW(dst_reg, dst_reg, src_reg));
                        EMIT(PPC_RAW_ADD(dst_reg_h, dst_reg_h, _R0));
                        EMIT(PPC_RAW_ADD(dst_reg_h, dst_reg_h, tmp_reg));
                        break;
                case BPF_ALU | BPF_MUL | BPF_X: /* (u32) dst *= (u32) src */
                        EMIT(PPC_RAW_MULW(dst_reg, dst_reg, src_reg));
                        break;
                case BPF_ALU | BPF_MUL | BPF_K: /* (u32) dst *= (u32) imm */
                        if (imm >= -32768 && imm < 32768) {
                                EMIT(PPC_RAW_MULI(dst_reg, dst_reg, imm));
                        } else {
                                PPC_LI32(_R0, imm);
                                EMIT(PPC_RAW_MULW(dst_reg, dst_reg, _R0));
                        }
                        break;
                case BPF_ALU64 | BPF_MUL | BPF_K: /* dst *= imm */
                        if (!imm) {
                                PPC_LI32(dst_reg, 0);
                                PPC_LI32(dst_reg_h, 0);
                                break;
                        }
                        if (imm == 1)
                                break;
                        if (imm == -1) {
                                EMIT(PPC_RAW_SUBFIC(dst_reg, dst_reg, 0));
                                EMIT(PPC_RAW_SUBFZE(dst_reg_h, dst_reg_h));
                                break;
                        }
                        bpf_set_seen_register(ctx, tmp_reg);
                        PPC_LI32(tmp_reg, imm);
                        EMIT(PPC_RAW_MULW(dst_reg_h, dst_reg_h, tmp_reg));
                        if (imm < 0)
                                EMIT(PPC_RAW_SUB(dst_reg_h, dst_reg_h, dst_reg));
                        EMIT(PPC_RAW_MULHWU(_R0, dst_reg, tmp_reg));
                        EMIT(PPC_RAW_MULW(dst_reg, dst_reg, tmp_reg));
                        EMIT(PPC_RAW_ADD(dst_reg_h, dst_reg_h, _R0));
                        break;
                case BPF_ALU | BPF_DIV | BPF_X: /* (u32) dst /= (u32) src */
                        EMIT(PPC_RAW_DIVWU(dst_reg, dst_reg, src_reg));
                        break;
                case BPF_ALU | BPF_MOD | BPF_X: /* (u32) dst %= (u32) src */
                        EMIT(PPC_RAW_DIVWU(_R0, dst_reg, src_reg));
                        EMIT(PPC_RAW_MULW(_R0, src_reg, _R0));
                        EMIT(PPC_RAW_SUB(dst_reg, dst_reg, _R0));
                        break;
                case BPF_ALU64 | BPF_DIV | BPF_X: /* dst /= src */
                        return -EOPNOTSUPP;
                case BPF_ALU64 | BPF_MOD | BPF_X: /* dst %= src */
                        return -EOPNOTSUPP;
                case BPF_ALU | BPF_DIV | BPF_K: /* (u32) dst /= (u32) imm */
                        if (!imm)
                                return -EINVAL;
                        if (imm == 1)
                                break;

                        PPC_LI32(_R0, imm);
                        EMIT(PPC_RAW_DIVWU(dst_reg, dst_reg, _R0));
                        break;
                case BPF_ALU | BPF_MOD | BPF_K: /* (u32) dst %= (u32) imm */
                        if (!imm)
                                return -EINVAL;

                        if (!is_power_of_2((u32)imm)) {
                                bpf_set_seen_register(ctx, tmp_reg);
                                PPC_LI32(tmp_reg, imm);
                                EMIT(PPC_RAW_DIVWU(_R0, dst_reg, tmp_reg));
                                EMIT(PPC_RAW_MULW(_R0, tmp_reg, _R0));
                                EMIT(PPC_RAW_SUB(dst_reg, dst_reg, _R0));
                                break;
                        }
                        if (imm == 1)
                                EMIT(PPC_RAW_LI(dst_reg, 0));
                        else
                                EMIT(PPC_RAW_RLWINM(dst_reg, dst_reg, 0, 32 - ilog2((u32)imm), 31));

                        break;
                case BPF_ALU64 | BPF_MOD | BPF_K: /* dst %= imm */
                        if (!imm)
                                return -EINVAL;
                        if (imm < 0)
                                imm = -imm;
                        if (!is_power_of_2(imm))
                                return -EOPNOTSUPP;
                        if (imm == 1)
                                EMIT(PPC_RAW_LI(dst_reg, 0));
                        else
                                EMIT(PPC_RAW_RLWINM(dst_reg, dst_reg, 0, 32 - ilog2(imm), 31));
                        EMIT(PPC_RAW_LI(dst_reg_h, 0));
                        break;
                case BPF_ALU64 | BPF_DIV | BPF_K: /* dst /= imm */
                        if (!imm)
                                return -EINVAL;
                        if (!is_power_of_2(abs(imm)))
                                return -EOPNOTSUPP;

                        if (imm < 0) {
                                EMIT(PPC_RAW_SUBFIC(dst_reg, dst_reg, 0));
                                EMIT(PPC_RAW_SUBFZE(dst_reg_h, dst_reg_h));
                                imm = -imm;
                        }
                        if (imm == 1)
                                break;
                        imm = ilog2(imm);
                        EMIT(PPC_RAW_RLWINM(dst_reg, dst_reg, 32 - imm, imm, 31));
                        EMIT(PPC_RAW_RLWIMI(dst_reg, dst_reg_h, 32 - imm, 0, imm - 1));
                        EMIT(PPC_RAW_SRAWI(dst_reg_h, dst_reg_h, imm));
                        break;
                case BPF_ALU | BPF_NEG: /* (u32) dst = -dst */
                        EMIT(PPC_RAW_NEG(dst_reg, dst_reg));
                        break;
                case BPF_ALU64 | BPF_NEG: /* dst = -dst */
                        EMIT(PPC_RAW_SUBFIC(dst_reg, dst_reg, 0));
                        EMIT(PPC_RAW_SUBFZE(dst_reg_h, dst_reg_h));
                        break;

                /*
                 * Logical operations: AND/OR/XOR/[A]LSH/[A]RSH
                 */
                case BPF_ALU64 | BPF_AND | BPF_X: /* dst = dst & src */
                        EMIT(PPC_RAW_AND(dst_reg, dst_reg, src_reg));
                        EMIT(PPC_RAW_AND(dst_reg_h, dst_reg_h, src_reg_h));
                        break;
                case BPF_ALU | BPF_AND | BPF_X: /* (u32) dst = dst & src */
                        EMIT(PPC_RAW_AND(dst_reg, dst_reg, src_reg));
                        break;
                case BPF_ALU64 | BPF_AND | BPF_K: /* dst = dst & imm */
                        if (imm >= 0)
                                EMIT(PPC_RAW_LI(dst_reg_h, 0));
                        fallthrough;
                case BPF_ALU | BPF_AND | BPF_K: /* (u32) dst = dst & imm */
                        if (!IMM_H(imm)) {
                                EMIT(PPC_RAW_ANDI(dst_reg, dst_reg, IMM_L(imm)));
                        } else if (!IMM_L(imm)) {
                                EMIT(PPC_RAW_ANDIS(dst_reg, dst_reg, IMM_H(imm)));
                        } else if (imm == (((1 << fls(imm)) - 1) ^ ((1 << (ffs(i) - 1)) - 1))) {
                                EMIT(PPC_RAW_RLWINM(dst_reg, dst_reg, 0,
                                                    32 - fls(imm), 32 - ffs(imm)));
                        } else {
                                PPC_LI32(_R0, imm);
                                EMIT(PPC_RAW_AND(dst_reg, dst_reg, _R0));
                        }
                        break;
                case BPF_ALU64 | BPF_OR | BPF_X: /* dst = dst | src */
                        EMIT(PPC_RAW_OR(dst_reg, dst_reg, src_reg));
                        EMIT(PPC_RAW_OR(dst_reg_h, dst_reg_h, src_reg_h));
                        break;
                case BPF_ALU | BPF_OR | BPF_X: /* dst = (u32) dst | (u32) src */
                        EMIT(PPC_RAW_OR(dst_reg, dst_reg, src_reg));
                        break;
                case BPF_ALU64 | BPF_OR | BPF_K:/* dst = dst | imm */
                        /* Sign-extended */
                        if (imm < 0)
                                EMIT(PPC_RAW_LI(dst_reg_h, -1));
                        fallthrough;
                case BPF_ALU | BPF_OR | BPF_K:/* dst = (u32) dst | (u32) imm */
                        if (IMM_L(imm))
                                EMIT(PPC_RAW_ORI(dst_reg, dst_reg, IMM_L(imm)));
                        if (IMM_H(imm))
                                EMIT(PPC_RAW_ORIS(dst_reg, dst_reg, IMM_H(imm)));
                        break;
                case BPF_ALU64 | BPF_XOR | BPF_X: /* dst ^= src */
                        if (dst_reg == src_reg) {
                                EMIT(PPC_RAW_LI(dst_reg, 0));
                                EMIT(PPC_RAW_LI(dst_reg_h, 0));
                        } else {
                                EMIT(PPC_RAW_XOR(dst_reg, dst_reg, src_reg));
                                EMIT(PPC_RAW_XOR(dst_reg_h, dst_reg_h, src_reg_h));
                        }
                        break;
                case BPF_ALU | BPF_XOR | BPF_X: /* (u32) dst ^= src */
                        if (dst_reg == src_reg)
                                EMIT(PPC_RAW_LI(dst_reg, 0));
                        else
                                EMIT(PPC_RAW_XOR(dst_reg, dst_reg, src_reg));
                        break;
                case BPF_ALU64 | BPF_XOR | BPF_K: /* dst ^= imm */
                        if (imm < 0)
                                EMIT(PPC_RAW_NOR(dst_reg_h, dst_reg_h, dst_reg_h));
                        fallthrough;
                case BPF_ALU | BPF_XOR | BPF_K: /* (u32) dst ^= (u32) imm */
                        if (IMM_L(imm))
                                EMIT(PPC_RAW_XORI(dst_reg, dst_reg, IMM_L(imm)));
                        if (IMM_H(imm))
                                EMIT(PPC_RAW_XORIS(dst_reg, dst_reg, IMM_H(imm)));
                        break;
                case BPF_ALU | BPF_LSH | BPF_X: /* (u32) dst <<= (u32) src */
                        EMIT(PPC_RAW_SLW(dst_reg, dst_reg, src_reg));
                        break;
                case BPF_ALU64 | BPF_LSH | BPF_X: /* dst <<= src; */
                        bpf_set_seen_register(ctx, tmp_reg);
                        EMIT(PPC_RAW_SUBFIC(_R0, src_reg, 32));
                        EMIT(PPC_RAW_SLW(dst_reg_h, dst_reg_h, src_reg));
                        EMIT(PPC_RAW_ADDI(tmp_reg, src_reg, 32));
                        EMIT(PPC_RAW_SRW(_R0, dst_reg, _R0));
                        EMIT(PPC_RAW_SLW(tmp_reg, dst_reg, tmp_reg));
                        EMIT(PPC_RAW_OR(dst_reg_h, dst_reg_h, _R0));
                        EMIT(PPC_RAW_SLW(dst_reg, dst_reg, src_reg));
                        EMIT(PPC_RAW_OR(dst_reg_h, dst_reg_h, tmp_reg));
                        break;
                case BPF_ALU | BPF_LSH | BPF_K: /* (u32) dst <<= (u32) imm */
                        if (!imm)
                                break;
                        EMIT(PPC_RAW_SLWI(dst_reg, dst_reg, imm));
                        break;
                case BPF_ALU64 | BPF_LSH | BPF_K: /* dst <<= imm */
                        if (imm < 0)
                                return -EINVAL;
                        if (!imm)
                                break;
                        if (imm < 32) {
                                EMIT(PPC_RAW_RLWINM(dst_reg_h, dst_reg_h, imm, 0, 31 - imm));
                                EMIT(PPC_RAW_RLWIMI(dst_reg_h, dst_reg, imm, 32 - imm, 31));
                                EMIT(PPC_RAW_RLWINM(dst_reg, dst_reg, imm, 0, 31 - imm));
                                break;
                        }
                        if (imm < 64)
                                EMIT(PPC_RAW_RLWINM(dst_reg_h, dst_reg, imm, 0, 31 - imm));
                        else
                                EMIT(PPC_RAW_LI(dst_reg_h, 0));
                        EMIT(PPC_RAW_LI(dst_reg, 0));
                        break;
                case BPF_ALU | BPF_RSH | BPF_X: /* (u32) dst >>= (u32) src */
                        EMIT(PPC_RAW_SRW(dst_reg, dst_reg, src_reg));
                        break;
                case BPF_ALU64 | BPF_RSH | BPF_X: /* dst >>= src */
                        bpf_set_seen_register(ctx, tmp_reg);
                        EMIT(PPC_RAW_SUBFIC(_R0, src_reg, 32));
                        EMIT(PPC_RAW_SRW(dst_reg, dst_reg, src_reg));
                        EMIT(PPC_RAW_ADDI(tmp_reg, src_reg, 32));
                        EMIT(PPC_RAW_SLW(_R0, dst_reg_h, _R0));
                        EMIT(PPC_RAW_SRW(tmp_reg, dst_reg_h, tmp_reg));
                        EMIT(PPC_RAW_OR(dst_reg, dst_reg, _R0));
                        EMIT(PPC_RAW_SRW(dst_reg_h, dst_reg_h, src_reg));
                        EMIT(PPC_RAW_OR(dst_reg, dst_reg, tmp_reg));
                        break;
                case BPF_ALU | BPF_RSH | BPF_K: /* (u32) dst >>= (u32) imm */
                        if (!imm)
                                break;
                        EMIT(PPC_RAW_SRWI(dst_reg, dst_reg, imm));
                        break;
                case BPF_ALU64 | BPF_RSH | BPF_K: /* dst >>= imm */
                        if (imm < 0)
                                return -EINVAL;
                        if (!imm)
                                break;
                        if (imm < 32) {
                                EMIT(PPC_RAW_RLWINM(dst_reg, dst_reg, 32 - imm, imm, 31));
                                EMIT(PPC_RAW_RLWIMI(dst_reg, dst_reg_h, 32 - imm, 0, imm - 1));
                                EMIT(PPC_RAW_RLWINM(dst_reg_h, dst_reg_h, 32 - imm, imm, 31));
                                break;
                        }
                        if (imm < 64)
                                EMIT(PPC_RAW_RLWINM(dst_reg, dst_reg_h, 64 - imm, imm - 32, 31));
                        else
                                EMIT(PPC_RAW_LI(dst_reg, 0));
                        EMIT(PPC_RAW_LI(dst_reg_h, 0));
                        break;
                case BPF_ALU | BPF_ARSH | BPF_X: /* (s32) dst >>= src */
                        EMIT(PPC_RAW_SRAW(dst_reg, dst_reg, src_reg));
                        break;
                case BPF_ALU64 | BPF_ARSH | BPF_X: /* (s64) dst >>= src */
                        bpf_set_seen_register(ctx, tmp_reg);
                        EMIT(PPC_RAW_SUBFIC(_R0, src_reg, 32));
                        EMIT(PPC_RAW_SRW(dst_reg, dst_reg, src_reg));
                        EMIT(PPC_RAW_SLW(_R0, dst_reg_h, _R0));
                        EMIT(PPC_RAW_ADDI(tmp_reg, src_reg, 32));
                        EMIT(PPC_RAW_OR(dst_reg, dst_reg, _R0));
                        EMIT(PPC_RAW_RLWINM(_R0, tmp_reg, 0, 26, 26));
                        EMIT(PPC_RAW_SRAW(tmp_reg, dst_reg_h, tmp_reg));
                        EMIT(PPC_RAW_SRAW(dst_reg_h, dst_reg_h, src_reg));
                        EMIT(PPC_RAW_SLW(tmp_reg, tmp_reg, _R0));
                        EMIT(PPC_RAW_OR(dst_reg, dst_reg, tmp_reg));
                        break;
                case BPF_ALU | BPF_ARSH | BPF_K: /* (s32) dst >>= imm */
                        if (!imm)
                                break;
                        EMIT(PPC_RAW_SRAWI(dst_reg, dst_reg, imm));
                        break;
                case BPF_ALU64 | BPF_ARSH | BPF_K: /* (s64) dst >>= imm */
                        if (imm < 0)
                                return -EINVAL;
                        if (!imm)
                                break;
                        if (imm < 32) {
                                EMIT(PPC_RAW_RLWINM(dst_reg, dst_reg, 32 - imm, imm, 31));
                                EMIT(PPC_RAW_RLWIMI(dst_reg, dst_reg_h, 32 - imm, 0, imm - 1));
                                EMIT(PPC_RAW_SRAWI(dst_reg_h, dst_reg_h, imm));
                                break;
                        }
                        if (imm < 64)
                                EMIT(PPC_RAW_SRAWI(dst_reg, dst_reg_h, imm - 32));
                        else
                                EMIT(PPC_RAW_SRAWI(dst_reg, dst_reg_h, 31));
                        EMIT(PPC_RAW_SRAWI(dst_reg_h, dst_reg_h, 31));
                        break;

                /*
                 * MOV
                 */
                case BPF_ALU64 | BPF_MOV | BPF_X: /* dst = src */
                        if (dst_reg == src_reg)
                                break;
                        EMIT(PPC_RAW_MR(dst_reg, src_reg));
                        EMIT(PPC_RAW_MR(dst_reg_h, src_reg_h));
                        break;
                case BPF_ALU | BPF_MOV | BPF_X: /* (u32) dst = src */
                        /* special mov32 for zext */
                        if (imm == 1)
                                EMIT(PPC_RAW_LI(dst_reg_h, 0));
                        else if (dst_reg != src_reg)
                                EMIT(PPC_RAW_MR(dst_reg, src_reg));
                        break;
                case BPF_ALU64 | BPF_MOV | BPF_K: /* dst = (s64) imm */
                        PPC_LI32(dst_reg, imm);
                        PPC_EX32(dst_reg_h, imm);
                        break;
                case BPF_ALU | BPF_MOV | BPF_K: /* (u32) dst = imm */
                        PPC_LI32(dst_reg, imm);
                        break;

                /*
                 * BPF_FROM_BE/LE
                 */
                case BPF_ALU | BPF_END | BPF_FROM_LE:
                        switch (imm) {
                        case 16:
                                /* Copy 16 bits to upper part */
                                EMIT(PPC_RAW_RLWIMI(dst_reg, dst_reg, 16, 0, 15));
                                /* Rotate 8 bits right & mask */
                                EMIT(PPC_RAW_RLWINM(dst_reg, dst_reg, 24, 16, 31));
                                break;
                        case 32:
                                /*
                                 * Rotate word left by 8 bits:
                                 * 2 bytes are already in their final position
                                 * -- byte 2 and 4 (of bytes 1, 2, 3 and 4)
                                 */
                                EMIT(PPC_RAW_RLWINM(_R0, dst_reg, 8, 0, 31));
                                /* Rotate 24 bits and insert byte 1 */
                                EMIT(PPC_RAW_RLWIMI(_R0, dst_reg, 24, 0, 7));
                                /* Rotate 24 bits and insert byte 3 */
                                EMIT(PPC_RAW_RLWIMI(_R0, dst_reg, 24, 16, 23));
                                EMIT(PPC_RAW_MR(dst_reg, _R0));
                                break;
                        case 64:
                                bpf_set_seen_register(ctx, tmp_reg);
                                EMIT(PPC_RAW_RLWINM(tmp_reg, dst_reg, 8, 0, 31));
                                EMIT(PPC_RAW_RLWINM(_R0, dst_reg_h, 8, 0, 31));
                                /* Rotate 24 bits and insert byte 1 */
                                EMIT(PPC_RAW_RLWIMI(tmp_reg, dst_reg, 24, 0, 7));
                                EMIT(PPC_RAW_RLWIMI(_R0, dst_reg_h, 24, 0, 7));
                                /* Rotate 24 bits and insert byte 3 */
                                EMIT(PPC_RAW_RLWIMI(tmp_reg, dst_reg, 24, 16, 23));
                                EMIT(PPC_RAW_RLWIMI(_R0, dst_reg_h, 24, 16, 23));
                                EMIT(PPC_RAW_MR(dst_reg, _R0));
                                EMIT(PPC_RAW_MR(dst_reg_h, tmp_reg));
                                break;
                        }
                        break;
                case BPF_ALU | BPF_END | BPF_FROM_BE:
                        switch (imm) {
                        case 16:
                                /* zero-extend 16 bits into 32 bits */
                                EMIT(PPC_RAW_RLWINM(dst_reg, dst_reg, 0, 16, 31));
                                break;
                        case 32:
                        case 64:
                                /* nop */
                                break;
                        }
                        break;

                /*
                 * BPF_ST NOSPEC (speculation barrier)
                 */
                case BPF_ST | BPF_NOSPEC:
                        break;

                /*
                 * BPF_ST(X)
                 */
                case BPF_STX | BPF_MEM | BPF_B: /* *(u8 *)(dst + off) = src */
                        EMIT(PPC_RAW_STB(src_reg, dst_reg, off));
                        break;
                case BPF_ST | BPF_MEM | BPF_B: /* *(u8 *)(dst + off) = imm */
                        PPC_LI32(_R0, imm);
                        EMIT(PPC_RAW_STB(_R0, dst_reg, off));
                        break;
                case BPF_STX | BPF_MEM | BPF_H: /* (u16 *)(dst + off) = src */
                        EMIT(PPC_RAW_STH(src_reg, dst_reg, off));
                        break;
                case BPF_ST | BPF_MEM | BPF_H: /* (u16 *)(dst + off) = imm */
                        PPC_LI32(_R0, imm);
                        EMIT(PPC_RAW_STH(_R0, dst_reg, off));
                        break;
                case BPF_STX | BPF_MEM | BPF_W: /* *(u32 *)(dst + off) = src */
                        EMIT(PPC_RAW_STW(src_reg, dst_reg, off));
                        break;
                case BPF_ST | BPF_MEM | BPF_W: /* *(u32 *)(dst + off) = imm */
                        PPC_LI32(_R0, imm);
                        EMIT(PPC_RAW_STW(_R0, dst_reg, off));
                        break;
                case BPF_STX | BPF_MEM | BPF_DW: /* (u64 *)(dst + off) = src */
                        EMIT(PPC_RAW_STW(src_reg_h, dst_reg, off));
                        EMIT(PPC_RAW_STW(src_reg, dst_reg, off + 4));
                        break;
                case BPF_ST | BPF_MEM | BPF_DW: /* *(u64 *)(dst + off) = imm */
                        PPC_LI32(_R0, imm);
                        EMIT(PPC_RAW_STW(_R0, dst_reg, off + 4));
                        PPC_EX32(_R0, imm);
                        EMIT(PPC_RAW_STW(_R0, dst_reg, off));
                        break;

                /*
                 * BPF_STX ATOMIC (atomic ops)
                 */
                case BPF_STX | BPF_ATOMIC | BPF_W:
                        if (imm != BPF_ADD) {
                                pr_err_ratelimited("eBPF filter atomic op code %02x (@%d) unsupported\n",
                                                   code, i);
                                return -ENOTSUPP;
                        }

                        /* *(u32 *)(dst + off) += src */

                        bpf_set_seen_register(ctx, tmp_reg);
                        /* Get offset into TMP_REG */
                        EMIT(PPC_RAW_LI(tmp_reg, off));
                        /* load value from memory into r0 */
                        EMIT(PPC_RAW_LWARX(_R0, tmp_reg, dst_reg, 0));
                        /* add value from src_reg into this */
                        EMIT(PPC_RAW_ADD(_R0, _R0, src_reg));
                        /* store result back */
                        EMIT(PPC_RAW_STWCX(_R0, tmp_reg, dst_reg));
                        /* we're done if this succeeded */
                        PPC_BCC_SHORT(COND_NE, (ctx->idx - 3) * 4);
                        break;

                case BPF_STX | BPF_ATOMIC | BPF_DW: /* *(u64 *)(dst + off) += src */
                        return -EOPNOTSUPP;

                /*
                 * BPF_LDX
                 */
                case BPF_LDX | BPF_MEM | BPF_B: /* dst = *(u8 *)(ul) (src + off) */
                case BPF_LDX | BPF_PROBE_MEM | BPF_B:
                case BPF_LDX | BPF_MEM | BPF_H: /* dst = *(u16 *)(ul) (src + off) */
                case BPF_LDX | BPF_PROBE_MEM | BPF_H:
                case BPF_LDX | BPF_MEM | BPF_W: /* dst = *(u32 *)(ul) (src + off) */
                case BPF_LDX | BPF_PROBE_MEM | BPF_W:
                case BPF_LDX | BPF_MEM | BPF_DW: /* dst = *(u64 *)(ul) (src + off) */
                case BPF_LDX | BPF_PROBE_MEM | BPF_DW:
                        /*
                         * As PTR_TO_BTF_ID that uses BPF_PROBE_MEM mode could either be a valid
                         * kernel pointer or NULL but not a userspace address, execute BPF_PROBE_MEM
                         * load only if addr is kernel address (see is_kernel_addr()), otherwise
                         * set dst_reg=0 and move on.
                         */
                        if (BPF_MODE(code) == BPF_PROBE_MEM) {
                                PPC_LI32(_R0, TASK_SIZE - off);
                                EMIT(PPC_RAW_CMPLW(src_reg, _R0));
                                PPC_BCC_SHORT(COND_GT, (ctx->idx + 4) * 4);
                                EMIT(PPC_RAW_LI(dst_reg, 0));
                                /*
                                 * For BPF_DW case, "li reg_h,0" would be needed when
                                 * !fp->aux->verifier_zext. Emit NOP otherwise.
                                 *
                                 * Note that "li reg_h,0" is emitted for BPF_B/H/W case,
                                 * if necessary. So, jump there insted of emitting an
                                 * additional "li reg_h,0" instruction.
                                 */
                                if (size == BPF_DW && !fp->aux->verifier_zext)
                                        EMIT(PPC_RAW_LI(dst_reg_h, 0));
                                else
                                        EMIT(PPC_RAW_NOP());
                                /*
                                 * Need to jump two instructions instead of one for BPF_DW case
                                 * as there are two load instructions for dst_reg_h & dst_reg
                                 * respectively.
                                 */
                                if (size == BPF_DW)
                                        PPC_JMP((ctx->idx + 3) * 4);
                                else
                                        PPC_JMP((ctx->idx + 2) * 4);
                        }

                        switch (size) {
                        case BPF_B:
                                EMIT(PPC_RAW_LBZ(dst_reg, src_reg, off));
                                break;
                        case BPF_H:
                                EMIT(PPC_RAW_LHZ(dst_reg, src_reg, off));
                                break;
                        case BPF_W:
                                EMIT(PPC_RAW_LWZ(dst_reg, src_reg, off));
                                break;
                        case BPF_DW:
                                EMIT(PPC_RAW_LWZ(dst_reg_h, src_reg, off));
                                EMIT(PPC_RAW_LWZ(dst_reg, src_reg, off + 4));
                                break;
                        }

                        if (size != BPF_DW && !fp->aux->verifier_zext)
                                EMIT(PPC_RAW_LI(dst_reg_h, 0));

                        if (BPF_MODE(code) == BPF_PROBE_MEM) {
                                int insn_idx = ctx->idx - 1;
                                int jmp_off = 4;

                                /*
                                 * In case of BPF_DW, two lwz instructions are emitted, one
                                 * for higher 32-bit and another for lower 32-bit. So, set
                                 * ex->insn to the first of the two and jump over both
                                 * instructions in fixup.
                                 *
                                 * Similarly, with !verifier_zext, two instructions are
                                 * emitted for BPF_B/H/W case. So, set ex->insn to the
                                 * instruction that could fault and skip over both
                                 * instructions.
                                 */
                                if (size == BPF_DW || !fp->aux->verifier_zext) {
                                        insn_idx -= 1;
                                        jmp_off += 4;
                                }

                                ret = bpf_add_extable_entry(fp, image, pass, ctx, insn_idx,
                                                            jmp_off, dst_reg);
                                if (ret)
                                        return ret;
                        }
                        break;

                /*
                 * Doubleword load
                 * 16 byte instruction that uses two 'struct bpf_insn'
                 */
                case BPF_LD | BPF_IMM | BPF_DW: /* dst = (u64) imm */
                        tmp_idx = ctx->idx;
                        PPC_LI32(dst_reg_h, (u32)insn[i + 1].imm);
                        PPC_LI32(dst_reg, (u32)insn[i].imm);
                        /* padding to allow full 4 instructions for later patching */
                        for (j = ctx->idx - tmp_idx; j < 4; j++)
                                EMIT(PPC_RAW_NOP());
                        /* Adjust for two bpf instructions */
                        addrs[++i] = ctx->idx * 4;
                        break;

                /*
                 * Return/Exit
                 */
                case BPF_JMP | BPF_EXIT:
                        /*
                         * If this isn't the very last instruction, branch to
                         * the epilogue. If we _are_ the last instruction,
                         * we'll just fall through to the epilogue.
                         */
                        if (i != flen - 1) {
                                ret = bpf_jit_emit_exit_insn(image, ctx, _R0, exit_addr);
                                if (ret)
                                        return ret;
                        }
                        /* else fall through to the epilogue */
                        break;

                /*
                 * Call kernel helper or bpf function
                 */
                case BPF_JMP | BPF_CALL:
                        ctx->seen |= SEEN_FUNC;

                        ret = bpf_jit_get_func_addr(fp, &insn[i], false,
                                                    &func_addr, &func_addr_fixed);
                        if (ret < 0)
                                return ret;

                        if (bpf_is_seen_register(ctx, bpf_to_ppc(BPF_REG_5))) {
                                EMIT(PPC_RAW_STW(bpf_to_ppc(BPF_REG_5) - 1, _R1, 8));
                                EMIT(PPC_RAW_STW(bpf_to_ppc(BPF_REG_5), _R1, 12));
                        }

                        ret = bpf_jit_emit_func_call_rel(image, ctx, func_addr);
                        if (ret)
                                return ret;

                        EMIT(PPC_RAW_MR(bpf_to_ppc(BPF_REG_0) - 1, _R3));
                        EMIT(PPC_RAW_MR(bpf_to_ppc(BPF_REG_0), _R4));
                        break;

                /*
                 * Jumps and branches
                 */
                case BPF_JMP | BPF_JA:
                        PPC_JMP(addrs[i + 1 + off]);
                        break;

                case BPF_JMP | BPF_JGT | BPF_K:
                case BPF_JMP | BPF_JGT | BPF_X:
                case BPF_JMP | BPF_JSGT | BPF_K:
                case BPF_JMP | BPF_JSGT | BPF_X:
                case BPF_JMP32 | BPF_JGT | BPF_K:
                case BPF_JMP32 | BPF_JGT | BPF_X:
                case BPF_JMP32 | BPF_JSGT | BPF_K:
                case BPF_JMP32 | BPF_JSGT | BPF_X:
                        true_cond = COND_GT;
                        goto cond_branch;
                case BPF_JMP | BPF_JLT | BPF_K:
                case BPF_JMP | BPF_JLT | BPF_X:
                case BPF_JMP | BPF_JSLT | BPF_K:
                case BPF_JMP | BPF_JSLT | BPF_X:
                case BPF_JMP32 | BPF_JLT | BPF_K:
                case BPF_JMP32 | BPF_JLT | BPF_X:
                case BPF_JMP32 | BPF_JSLT | BPF_K:
                case BPF_JMP32 | BPF_JSLT | BPF_X:
                        true_cond = COND_LT;
                        goto cond_branch;
                case BPF_JMP | BPF_JGE | BPF_K:
                case BPF_JMP | BPF_JGE | BPF_X:

                case BPF_JMP | BPF_JSGE | BPF_K:
                case BPF_JMP | BPF_JSGE | BPF_X:
                case BPF_JMP32 | BPF_JGE | BPF_K:
                case BPF_JMP32 | BPF_JGE | BPF_X:
                case BPF_JMP32 | BPF_JSGE | BPF_K:
                case BPF_JMP32 | BPF_JSGE | BPF_X:
                        true_cond = COND_GE;
                        goto cond_branch;
                case BPF_JMP | BPF_JLE | BPF_K:
                case BPF_JMP | BPF_JLE | BPF_X:
                case BPF_JMP | BPF_JSLE | BPF_K:
                case BPF_JMP | BPF_JSLE | BPF_X:
                case BPF_JMP32 | BPF_JLE | BPF_K:
                case BPF_JMP32 | BPF_JLE | BPF_X:
                case BPF_JMP32 | BPF_JSLE | BPF_K:
                case BPF_JMP32 | BPF_JSLE | BPF_X:
                        true_cond = COND_LE;
                        goto cond_branch;
                case BPF_JMP | BPF_JEQ | BPF_K:
                case BPF_JMP | BPF_JEQ | BPF_X:
                case BPF_JMP32 | BPF_JEQ | BPF_K:
                case BPF_JMP32 | BPF_JEQ | BPF_X:
                        true_cond = COND_EQ;
                        goto cond_branch;
                case BPF_JMP | BPF_JNE | BPF_K:
                case BPF_JMP | BPF_JNE | BPF_X:
                case BPF_JMP32 | BPF_JNE | BPF_K:
                case BPF_JMP32 | BPF_JNE | BPF_X:
                        true_cond = COND_NE;
                        goto cond_branch;
                case BPF_JMP | BPF_JSET | BPF_K:
                case BPF_JMP | BPF_JSET | BPF_X:
                case BPF_JMP32 | BPF_JSET | BPF_K:
                case BPF_JMP32 | BPF_JSET | BPF_X:
                        true_cond = COND_NE;
                        /* fallthrough; */

cond_branch:
                        switch (code) {
                        case BPF_JMP | BPF_JGT | BPF_X:
                        case BPF_JMP | BPF_JLT | BPF_X:
                        case BPF_JMP | BPF_JGE | BPF_X:
                        case BPF_JMP | BPF_JLE | BPF_X:
                        case BPF_JMP | BPF_JEQ | BPF_X:
                        case BPF_JMP | BPF_JNE | BPF_X:
                                /* unsigned comparison */
                                EMIT(PPC_RAW_CMPLW(dst_reg_h, src_reg_h));
                                PPC_BCC_SHORT(COND_NE, (ctx->idx + 2) * 4);
                                EMIT(PPC_RAW_CMPLW(dst_reg, src_reg));
                                break;
                        case BPF_JMP32 | BPF_JGT | BPF_X:
                        case BPF_JMP32 | BPF_JLT | BPF_X:
                        case BPF_JMP32 | BPF_JGE | BPF_X:
                        case BPF_JMP32 | BPF_JLE | BPF_X:
                        case BPF_JMP32 | BPF_JEQ | BPF_X:
                        case BPF_JMP32 | BPF_JNE | BPF_X:
                                /* unsigned comparison */
                                EMIT(PPC_RAW_CMPLW(dst_reg, src_reg));
                                break;
                        case BPF_JMP | BPF_JSGT | BPF_X:
                        case BPF_JMP | BPF_JSLT | BPF_X:
                        case BPF_JMP | BPF_JSGE | BPF_X:
                        case BPF_JMP | BPF_JSLE | BPF_X:
                                /* signed comparison */
                                EMIT(PPC_RAW_CMPW(dst_reg_h, src_reg_h));
                                PPC_BCC_SHORT(COND_NE, (ctx->idx + 2) * 4);
                                EMIT(PPC_RAW_CMPLW(dst_reg, src_reg));
                                break;
                        case BPF_JMP32 | BPF_JSGT | BPF_X:
                        case BPF_JMP32 | BPF_JSLT | BPF_X:
                        case BPF_JMP32 | BPF_JSGE | BPF_X:
                        case BPF_JMP32 | BPF_JSLE | BPF_X:
                                /* signed comparison */
                                EMIT(PPC_RAW_CMPW(dst_reg, src_reg));
                                break;
                        case BPF_JMP | BPF_JSET | BPF_X:
                                EMIT(PPC_RAW_AND_DOT(_R0, dst_reg_h, src_reg_h));
                                PPC_BCC_SHORT(COND_NE, (ctx->idx + 2) * 4);
                                EMIT(PPC_RAW_AND_DOT(_R0, dst_reg, src_reg));
                                break;
                        case BPF_JMP32 | BPF_JSET | BPF_X: {
                                EMIT(PPC_RAW_AND_DOT(_R0, dst_reg, src_reg));
                                break;
                        case BPF_JMP | BPF_JNE | BPF_K:
                        case BPF_JMP | BPF_JEQ | BPF_K:
                        case BPF_JMP | BPF_JGT | BPF_K:
                        case BPF_JMP | BPF_JLT | BPF_K:
                        case BPF_JMP | BPF_JGE | BPF_K:
                        case BPF_JMP | BPF_JLE | BPF_K:
                                /*
                                 * Need sign-extended load, so only positive
                                 * values can be used as imm in cmplwi
                                 */
                                if (imm >= 0 && imm < 32768) {
                                        EMIT(PPC_RAW_CMPLWI(dst_reg_h, 0));
                                        PPC_BCC_SHORT(COND_NE, (ctx->idx + 2) * 4);
                                        EMIT(PPC_RAW_CMPLWI(dst_reg, imm));
                                } else {
                                        /* sign-extending load ... but unsigned comparison */
                                        PPC_EX32(_R0, imm);
                                        EMIT(PPC_RAW_CMPLW(dst_reg_h, _R0));
                                        PPC_LI32(_R0, imm);
                                        PPC_BCC_SHORT(COND_NE, (ctx->idx + 2) * 4);
                                        EMIT(PPC_RAW_CMPLW(dst_reg, _R0));
                                }
                                break;
                        case BPF_JMP32 | BPF_JNE | BPF_K:
                        case BPF_JMP32 | BPF_JEQ | BPF_K:
                        case BPF_JMP32 | BPF_JGT | BPF_K:
                        case BPF_JMP32 | BPF_JLT | BPF_K:
                        case BPF_JMP32 | BPF_JGE | BPF_K:
                        case BPF_JMP32 | BPF_JLE | BPF_K:
                                if (imm >= 0 && imm < 65536) {
                                        EMIT(PPC_RAW_CMPLWI(dst_reg, imm));
                                } else {
                                        PPC_LI32(_R0, imm);
                                        EMIT(PPC_RAW_CMPLW(dst_reg, _R0));
                                }
                                break;
                        }
                        case BPF_JMP | BPF_JSGT | BPF_K:
                        case BPF_JMP | BPF_JSLT | BPF_K:
                        case BPF_JMP | BPF_JSGE | BPF_K:
                        case BPF_JMP | BPF_JSLE | BPF_K:
                                if (imm >= 0 && imm < 65536) {
                                        EMIT(PPC_RAW_CMPWI(dst_reg_h, imm < 0 ? -1 : 0));
                                        PPC_BCC_SHORT(COND_NE, (ctx->idx + 2) * 4);
                                        EMIT(PPC_RAW_CMPLWI(dst_reg, imm));
                                } else {
                                        /* sign-extending load */
                                        EMIT(PPC_RAW_CMPWI(dst_reg_h, imm < 0 ? -1 : 0));
                                        PPC_LI32(_R0, imm);
                                        PPC_BCC_SHORT(COND_NE, (ctx->idx + 2) * 4);
                                        EMIT(PPC_RAW_CMPLW(dst_reg, _R0));
                                }
                                break;
                        case BPF_JMP32 | BPF_JSGT | BPF_K:
                        case BPF_JMP32 | BPF_JSLT | BPF_K:
                        case BPF_JMP32 | BPF_JSGE | BPF_K:
                        case BPF_JMP32 | BPF_JSLE | BPF_K:
                                /*
                                 * signed comparison, so any 16-bit value
                                 * can be used in cmpwi
                                 */
                                if (imm >= -32768 && imm < 32768) {
                                        EMIT(PPC_RAW_CMPWI(dst_reg, imm));
                                } else {
                                        /* sign-extending load */
                                        PPC_LI32(_R0, imm);
                                        EMIT(PPC_RAW_CMPW(dst_reg, _R0));
                                }
                                break;
                        case BPF_JMP | BPF_JSET | BPF_K:
                                /* andi does not sign-extend the immediate */
                                if (imm >= 0 && imm < 32768) {
                                        /* PPC_ANDI is _only/always_ dot-form */
                                        EMIT(PPC_RAW_ANDI(_R0, dst_reg, imm));
                                } else {
                                        PPC_LI32(_R0, imm);
                                        if (imm < 0) {
                                                EMIT(PPC_RAW_CMPWI(dst_reg_h, 0));
                                                PPC_BCC_SHORT(COND_NE, (ctx->idx + 2) * 4);
                                        }
                                        EMIT(PPC_RAW_AND_DOT(_R0, dst_reg, _R0));
                                }
                                break;
                        case BPF_JMP32 | BPF_JSET | BPF_K:
                                /* andi does not sign-extend the immediate */
                                if (imm >= 0 && imm < 32768) {
                                        /* PPC_ANDI is _only/always_ dot-form */
                                        EMIT(PPC_RAW_ANDI(_R0, dst_reg, imm));
                                } else {
                                        PPC_LI32(_R0, imm);
                                        EMIT(PPC_RAW_AND_DOT(_R0, dst_reg, _R0));
                                }
                                break;
                        }
                        PPC_BCC(true_cond, addrs[i + 1 + off]);
                        break;

                /*
                 * Tail call
                 */
                case BPF_JMP | BPF_TAIL_CALL:
                        ctx->seen |= SEEN_TAILCALL;
                        ret = bpf_jit_emit_tail_call(image, ctx, addrs[i + 1]);
                        if (ret < 0)
                                return ret;
                        break;

                default:
                        /*
                         * The filter contains something cruel & unusual.
                         * We don't handle it, but also there shouldn't be
                         * anything missing from our list.
                         */
                        pr_err_ratelimited("eBPF filter opcode %04x (@%d) unsupported\n", code, i);
                        return -EOPNOTSUPP;
                }
                if (BPF_CLASS(code) == BPF_ALU && !fp->aux->verifier_zext &&
                    !insn_is_zext(&insn[i + 1]) && !(BPF_OP(code) == BPF_END && imm == 64))
                        EMIT(PPC_RAW_LI(dst_reg_h, 0));
        }

        /* Set end-of-body-code address for exit. */
        addrs[i] = ctx->idx * 4;

        return 0;
}