Re: [PATCH v3 2/3] LoongArch: BPF: Clean up and decouple is32 parameter from move_imm()

[Hengqi Chen]

On Fri, Oct 16, 2026 at 4:10 PM Tiezhu Yang <yangtiezhu@xxxxxxxxxxx> wrote:
>
> The current move_imm() relies on the 'is32' parameter for ALU32 and JMP32,
> forcing the helper to internally clear the upper 32 bits. However, this is
> redundant for 64-bit immediate loads. Furthermore, it is even undesirable
> for load/store signed address offset computations.
>
> Clean up move_imm() by removing the 'is32' parameter which allows it to
> focus on loading values, while moving the zero-extension logic outward to
> the explicit callers. For 64-bit and load-store operations, just drop the
> parameter.
>
> This is preparation for later patch, no functional changes.
>
> Signed-off-by: Tiezhu Yang <yangtiezhu@xxxxxxxxxxx>
> ---

Acked-by: Hengqi Chen <hengqi.chen@xxxxxxxxx>

>  arch/loongarch/net/bpf_jit.c | 102 +++++++++++++++++++----------------
>  arch/loongarch/net/bpf_jit.h |   7 +--
>  2 files changed, 58 insertions(+), 51 deletions(-)
>
> diff --git a/arch/loongarch/net/bpf_jit.c b/arch/loongarch/net/bpf_jit.c
> index e78eb582c300..77cd96a6f84c 100644
> --- a/arch/loongarch/net/bpf_jit.c
> +++ b/arch/loongarch/net/bpf_jit.c
> @@ -194,7 +194,7 @@ static void build_prologue(struct jit_ctx *ctx)
>         ctx->stack_size = stack_adjust;
>
>         if (ctx->arena_vm_start)
> -               move_imm(ctx, REG_ARENA, ctx->arena_vm_start, false);
> +               move_imm(ctx, REG_ARENA, ctx->arena_vm_start);
>  }
>
>  static void __build_epilogue(struct jit_ctx *ctx, bool is_tail_call)
> @@ -339,7 +339,7 @@ static int emit_bpf_tail_call(struct jit_ctx *ctx, int insn)
>
>  static void emit_store_stack_imm64(struct jit_ctx *ctx, int reg, int stack_off, u64 imm64)
>  {
> -       move_imm(ctx, reg, imm64, false);
> +       move_imm(ctx, reg, imm64);
>         emit_insn(ctx, std, reg, LOONGARCH_GPR_FP, stack_off);
>  }
>
> @@ -355,7 +355,7 @@ static int emit_atomic_rmw(const struct bpf_insn *insn, struct jit_ctx *ctx)
>         const s32 imm = insn->imm;
>         const bool isdw = BPF_SIZE(insn->code) == BPF_DW;
>
> -       move_imm(ctx, t1, off, false);
> +       move_imm(ctx, t1, off);
>         emit_insn(ctx, addd, t1, dst, t1);
>         move_reg(ctx, t3, src);
>
> @@ -528,7 +528,7 @@ static int emit_atomic_ld_st(const struct bpf_insn *insn, struct jit_ctx *ctx)
>                         if (is_signed_imm12(off)) {
>                                 emit_insn(ctx, ldbu, dst, src, off);
>                         } else {
> -                               move_imm(ctx, t1, off, false);
> +                               move_imm(ctx, t1, off);
>                                 emit_insn(ctx, ldxbu, dst, src, t1);
>                         }
>                         break;
> @@ -536,7 +536,7 @@ static int emit_atomic_ld_st(const struct bpf_insn *insn, struct jit_ctx *ctx)
>                         if (is_signed_imm12(off)) {
>                                 emit_insn(ctx, ldhu, dst, src, off);
>                         } else {
> -                               move_imm(ctx, t1, off, false);
> +                               move_imm(ctx, t1, off);
>                                 emit_insn(ctx, ldxhu, dst, src, t1);
>                         }
>                         break;
> @@ -544,7 +544,7 @@ static int emit_atomic_ld_st(const struct bpf_insn *insn, struct jit_ctx *ctx)
>                         if (is_signed_imm12(off)) {
>                                 emit_insn(ctx, ldwu, dst, src, off);
>                         } else {
> -                               move_imm(ctx, t1, off, false);
> +                               move_imm(ctx, t1, off);
>                                 emit_insn(ctx, ldxwu, dst, src, t1);
>                         }
>                         break;
> @@ -552,7 +552,7 @@ static int emit_atomic_ld_st(const struct bpf_insn *insn, struct jit_ctx *ctx)
>                         if (is_signed_imm12(off)) {
>                                 emit_insn(ctx, ldd, dst, src, off);
>                         } else {
> -                               move_imm(ctx, t1, off, false);
> +                               move_imm(ctx, t1, off);
>                                 emit_insn(ctx, ldxd, dst, src, t1);
>                         }
>                         break;
> @@ -567,7 +567,7 @@ static int emit_atomic_ld_st(const struct bpf_insn *insn, struct jit_ctx *ctx)
>                         if (is_signed_imm12(off)) {
>                                 emit_insn(ctx, stb, src, dst, off);
>                         } else {
> -                               move_imm(ctx, t1, off, false);
> +                               move_imm(ctx, t1, off);
>                                 emit_insn(ctx, stxb, src, dst, t1);
>                         }
>                         break;
> @@ -575,7 +575,7 @@ static int emit_atomic_ld_st(const struct bpf_insn *insn, struct jit_ctx *ctx)
>                         if (is_signed_imm12(off)) {
>                                 emit_insn(ctx, sth, src, dst, off);
>                         } else {
> -                               move_imm(ctx, t1, off, false);
> +                               move_imm(ctx, t1, off);
>                                 emit_insn(ctx, stxh, src, dst, t1);
>                         }
>                         break;
> @@ -583,7 +583,7 @@ static int emit_atomic_ld_st(const struct bpf_insn *insn, struct jit_ctx *ctx)
>                         if (is_signed_imm12(off)) {
>                                 emit_insn(ctx, stw, src, dst, off);
>                         } else {
> -                               move_imm(ctx, t1, off, false);
> +                               move_imm(ctx, t1, off);
>                                 emit_insn(ctx, stxw, src, dst, t1);
>                         }
>                         break;
> @@ -591,7 +591,7 @@ static int emit_atomic_ld_st(const struct bpf_insn *insn, struct jit_ctx *ctx)
>                         if (is_signed_imm12(off)) {
>                                 emit_insn(ctx, std, src, dst, off);
>                         } else {
> -                               move_imm(ctx, t1, off, false);
> +                               move_imm(ctx, t1, off);
>                                 emit_insn(ctx, stxd, src, dst, t1);
>                         }
>                         break;
> @@ -716,7 +716,7 @@ static int build_insn(const struct bpf_insn *insn, struct jit_ctx *ctx, bool ext
>                 if (insn_is_cast_user(insn)) {
>                         move_reg(ctx, t1, src);
>                         emit_zext_32(ctx, t1, true);
> -                       move_imm(ctx, dst, (ctx->user_vm_start >> 32) << 32, false);
> +                       move_imm(ctx, dst, (ctx->user_vm_start >> 32) << 32);
>                         emit_insn(ctx, beq, t1, LOONGARCH_GPR_ZERO, 2);
>                         emit_insn(ctx, or, t1, dst, t1);
>                         move_reg(ctx, dst, t1);
> @@ -753,7 +753,8 @@ static int build_insn(const struct bpf_insn *insn, struct jit_ctx *ctx, bool ext
>         /* dst = imm */
>         case BPF_ALU | BPF_MOV | BPF_K:
>         case BPF_ALU64 | BPF_MOV | BPF_K:
> -               move_imm(ctx, dst, imm, is32);
> +               move_imm(ctx, dst, imm);
> +               emit_zext_32(ctx, dst, is32);
>                 break;
>
>         /* dst = dst + src */
> @@ -769,7 +770,8 @@ static int build_insn(const struct bpf_insn *insn, struct jit_ctx *ctx, bool ext
>                 if (is_signed_imm12(imm)) {
>                         emit_insn(ctx, addid, dst, dst, imm);
>                 } else {
> -                       move_imm(ctx, t1, imm, is32);
> +                       move_imm(ctx, t1, imm);
> +                       emit_zext_32(ctx, t1, is32);
>                         emit_insn(ctx, addd, dst, dst, t1);
>                 }
>                 emit_zext_32(ctx, dst, is32);
> @@ -788,7 +790,8 @@ static int build_insn(const struct bpf_insn *insn, struct jit_ctx *ctx, bool ext
>                 if (is_signed_imm12(-imm)) {
>                         emit_insn(ctx, addid, dst, dst, -imm);
>                 } else {
> -                       move_imm(ctx, t1, imm, is32);
> +                       move_imm(ctx, t1, imm);
> +                       emit_zext_32(ctx, t1, is32);
>                         emit_insn(ctx, subd, dst, dst, t1);
>                 }
>                 emit_zext_32(ctx, dst, is32);
> @@ -804,7 +807,8 @@ static int build_insn(const struct bpf_insn *insn, struct jit_ctx *ctx, bool ext
>         /* dst = dst * imm */
>         case BPF_ALU | BPF_MUL | BPF_K:
>         case BPF_ALU64 | BPF_MUL | BPF_K:
> -               move_imm(ctx, t1, imm, is32);
> +               move_imm(ctx, t1, imm);
> +               emit_zext_32(ctx, t1, is32);
>                 emit_insn(ctx, muld, dst, dst, t1);
>                 emit_zext_32(ctx, dst, is32);
>                 break;
> @@ -831,12 +835,13 @@ static int build_insn(const struct bpf_insn *insn, struct jit_ctx *ctx, bool ext
>         case BPF_ALU | BPF_DIV | BPF_K:
>         case BPF_ALU64 | BPF_DIV | BPF_K:
>                 if (!off) {
> -                       move_imm(ctx, t1, imm, is32);
> +                       move_imm(ctx, t1, imm);
> +                       emit_zext_32(ctx, t1, is32);
>                         emit_zext_32(ctx, dst, is32);
>                         emit_insn(ctx, divdu, dst, dst, t1);
>                         emit_zext_32(ctx, dst, is32);
>                 } else {
> -                       move_imm(ctx, t1, imm, false);
> +                       move_imm(ctx, t1, imm);
>                         emit_sext_32(ctx, t1, is32);
>                         emit_sext_32(ctx, dst, is32);
>                         emit_insn(ctx, divd, dst, dst, t1);
> @@ -866,12 +871,13 @@ static int build_insn(const struct bpf_insn *insn, struct jit_ctx *ctx, bool ext
>         case BPF_ALU | BPF_MOD | BPF_K:
>         case BPF_ALU64 | BPF_MOD | BPF_K:
>                 if (!off) {
> -                       move_imm(ctx, t1, imm, is32);
> +                       move_imm(ctx, t1, imm);
> +                       emit_zext_32(ctx, t1, is32);
>                         emit_zext_32(ctx, dst, is32);
>                         emit_insn(ctx, moddu, dst, dst, t1);
>                         emit_zext_32(ctx, dst, is32);
>                 } else {
> -                       move_imm(ctx, t1, imm, false);
> +                       move_imm(ctx, t1, imm);
>                         emit_sext_32(ctx, t1, is32);
>                         emit_sext_32(ctx, dst, is32);
>                         emit_insn(ctx, modd, dst, dst, t1);
> @@ -899,7 +905,8 @@ static int build_insn(const struct bpf_insn *insn, struct jit_ctx *ctx, bool ext
>                 if (is_unsigned_imm12(imm)) {
>                         emit_insn(ctx, andi, dst, dst, imm);
>                 } else {
> -                       move_imm(ctx, t1, imm, is32);
> +                       move_imm(ctx, t1, imm);
> +                       emit_zext_32(ctx, t1, is32);
>                         emit_insn(ctx, and, dst, dst, t1);
>                 }
>                 emit_zext_32(ctx, dst, is32);
> @@ -918,7 +925,8 @@ static int build_insn(const struct bpf_insn *insn, struct jit_ctx *ctx, bool ext
>                 if (is_unsigned_imm12(imm)) {
>                         emit_insn(ctx, ori, dst, dst, imm);
>                 } else {
> -                       move_imm(ctx, t1, imm, is32);
> +                       move_imm(ctx, t1, imm);
> +                       emit_zext_32(ctx, t1, is32);
>                         emit_insn(ctx, or, dst, dst, t1);
>                 }
>                 emit_zext_32(ctx, dst, is32);
> @@ -937,7 +945,8 @@ static int build_insn(const struct bpf_insn *insn, struct jit_ctx *ctx, bool ext
>                 if (is_unsigned_imm12(imm)) {
>                         emit_insn(ctx, xori, dst, dst, imm);
>                 } else {
> -                       move_imm(ctx, t1, imm, is32);
> +                       move_imm(ctx, t1, imm);
> +                       emit_zext_32(ctx, t1, is32);
>                         emit_insn(ctx, xor, dst, dst, t1);
>                 }
>                 emit_zext_32(ctx, dst, is32);
> @@ -1097,7 +1106,7 @@ static int build_insn(const struct bpf_insn *insn, struct jit_ctx *ctx, bool ext
>         case BPF_JMP32 | BPF_JSLE | BPF_K:
>                 jmp_offset = bpf2la_offset(i, off, ctx);
>                 if (imm) {
> -                       move_imm(ctx, t1, imm, false);
> +                       move_imm(ctx, t1, imm);
>                         tm = t1;
>                 } else {
>                         /* If imm is 0, simply use zero register. */
> @@ -1129,7 +1138,8 @@ static int build_insn(const struct bpf_insn *insn, struct jit_ctx *ctx, bool ext
>         case BPF_JMP | BPF_JSET | BPF_K:
>         case BPF_JMP32 | BPF_JSET | BPF_K:
>                 jmp_offset = bpf2la_offset(i, off, ctx);
> -               move_imm(ctx, t1, imm, is32);
> +               move_imm(ctx, t1, imm);
> +               emit_zext_32(ctx, t1, is32);
>                 emit_insn(ctx, and, t1, dst, t1);
>                 emit_zext_32(ctx, t1, is32);
>                 if (emit_cond_jmp(ctx, cond, t1, LOONGARCH_GPR_ZERO, jmp_offset) < 0)
> @@ -1227,7 +1237,7 @@ static int build_insn(const struct bpf_insn *insn, struct jit_ctx *ctx, bool ext
>                 if (bpf_pseudo_func(insn))
>                         move_addr(ctx, dst, imm64);
>                 else
> -                       move_imm(ctx, dst, imm64, is32);
> +                       move_imm(ctx, dst, imm64);
>                 return 1;
>         }
>
> @@ -1268,7 +1278,7 @@ static int build_insn(const struct bpf_insn *insn, struct jit_ctx *ctx, bool ext
>                                 else
>                                         emit_insn(ctx, ldbu, dst, src, off);
>                         } else {
> -                               move_imm(ctx, t1, off, is32);
> +                               move_imm(ctx, t1, off);
>                                 if (sign_extend)
>                                         emit_insn(ctx, ldxb, dst, src, t1);
>                                 else
> @@ -1282,7 +1292,7 @@ static int build_insn(const struct bpf_insn *insn, struct jit_ctx *ctx, bool ext
>                                 else
>                                         emit_insn(ctx, ldhu, dst, src, off);
>                         } else {
> -                               move_imm(ctx, t1, off, is32);
> +                               move_imm(ctx, t1, off);
>                                 if (sign_extend)
>                                         emit_insn(ctx, ldxh, dst, src, t1);
>                                 else
> @@ -1296,7 +1306,7 @@ static int build_insn(const struct bpf_insn *insn, struct jit_ctx *ctx, bool ext
>                                 else
>                                         emit_insn(ctx, ldwu, dst, src, off);
>                         } else {
> -                               move_imm(ctx, t1, off, is32);
> +                               move_imm(ctx, t1, off);
>                                 if (sign_extend)
>                                         emit_insn(ctx, ldxw, dst, src, t1);
>                                 else
> @@ -1304,7 +1314,7 @@ static int build_insn(const struct bpf_insn *insn, struct jit_ctx *ctx, bool ext
>                         }
>                         break;
>                 case BPF_DW:
> -                       move_imm(ctx, t1, off, is32);
> +                       move_imm(ctx, t1, off);
>                         emit_insn(ctx, ldxd, dst, src, t1);
>                         break;
>                 }
> @@ -1331,42 +1341,42 @@ static int build_insn(const struct bpf_insn *insn, struct jit_ctx *ctx, bool ext
>
>                 switch (BPF_SIZE(code)) {
>                 case BPF_B:
> -                       move_imm(ctx, t1, imm, is32);
> +                       move_imm(ctx, t1, imm);
>                         if (is_signed_imm12(off)) {
>                                 emit_insn(ctx, stb, t1, dst, off);
>                         } else {
> -                               move_imm(ctx, t2, off, is32);
> +                               move_imm(ctx, t2, off);
>                                 emit_insn(ctx, stxb, t1, dst, t2);
>                         }
>                         break;
>                 case BPF_H:
> -                       move_imm(ctx, t1, imm, is32);
> +                       move_imm(ctx, t1, imm);
>                         if (is_signed_imm12(off)) {
>                                 emit_insn(ctx, sth, t1, dst, off);
>                         } else {
> -                               move_imm(ctx, t2, off, is32);
> +                               move_imm(ctx, t2, off);
>                                 emit_insn(ctx, stxh, t1, dst, t2);
>                         }
>                         break;
>                 case BPF_W:
> -                       move_imm(ctx, t1, imm, is32);
> +                       move_imm(ctx, t1, imm);
>                         if (is_signed_imm12(off)) {
>                                 emit_insn(ctx, stw, t1, dst, off);
>                         } else if (is_signed_imm14(off)) {
>                                 emit_insn(ctx, stptrw, t1, dst, off);
>                         } else {
> -                               move_imm(ctx, t2, off, is32);
> +                               move_imm(ctx, t2, off);
>                                 emit_insn(ctx, stxw, t1, dst, t2);
>                         }
>                         break;
>                 case BPF_DW:
> -                       move_imm(ctx, t1, imm, is32);
> +                       move_imm(ctx, t1, imm);
>                         if (is_signed_imm12(off)) {
>                                 emit_insn(ctx, std, t1, dst, off);
>                         } else if (is_signed_imm14(off)) {
>                                 emit_insn(ctx, stptrd, t1, dst, off);
>                         } else {
> -                               move_imm(ctx, t2, off, is32);
> +                               move_imm(ctx, t2, off);
>                                 emit_insn(ctx, stxd, t1, dst, t2);
>                         }
>                         break;
> @@ -1397,7 +1407,7 @@ static int build_insn(const struct bpf_insn *insn, struct jit_ctx *ctx, bool ext
>                         if (is_signed_imm12(off)) {
>                                 emit_insn(ctx, stb, src, dst, off);
>                         } else {
> -                               move_imm(ctx, t1, off, is32);
> +                               move_imm(ctx, t1, off);
>                                 emit_insn(ctx, stxb, src, dst, t1);
>                         }
>                         break;
> @@ -1405,7 +1415,7 @@ static int build_insn(const struct bpf_insn *insn, struct jit_ctx *ctx, bool ext
>                         if (is_signed_imm12(off)) {
>                                 emit_insn(ctx, sth, src, dst, off);
>                         } else {
> -                               move_imm(ctx, t1, off, is32);
> +                               move_imm(ctx, t1, off);
>                                 emit_insn(ctx, stxh, src, dst, t1);
>                         }
>                         break;
> @@ -1415,7 +1425,7 @@ static int build_insn(const struct bpf_insn *insn, struct jit_ctx *ctx, bool ext
>                         } else if (is_signed_imm14(off)) {
>                                 emit_insn(ctx, stptrw, src, dst, off);
>                         } else {
> -                               move_imm(ctx, t1, off, is32);
> +                               move_imm(ctx, t1, off);
>                                 emit_insn(ctx, stxw, src, dst, t1);
>                         }
>                         break;
> @@ -1425,7 +1435,7 @@ static int build_insn(const struct bpf_insn *insn, struct jit_ctx *ctx, bool ext
>                         } else if (is_signed_imm14(off)) {
>                                 emit_insn(ctx, stptrd, src, dst, off);
>                         } else {
> -                               move_imm(ctx, t1, off, is32);
> +                               move_imm(ctx, t1, off);
>                                 emit_insn(ctx, stxd, src, dst, t1);
>                         }
>                         break;
> @@ -1537,7 +1547,7 @@ static int emit_jump_and_link(struct jit_ctx *ctx, u8 rd, u64 target)
>                 return -EFAULT;
>         }
>
> -       move_imm(ctx, LOONGARCH_GPR_T1, target, false);
> +       move_imm(ctx, LOONGARCH_GPR_T1, target);
>         emit_insn(ctx, jirl, rd, LOONGARCH_GPR_T1, 0);
>
>         return 0;
> @@ -1734,7 +1744,7 @@ static int invoke_bpf_prog(struct jit_ctx *ctx, struct bpf_tramp_image *im,
>                 emit_insn(ctx, std, LOONGARCH_GPR_ZERO, LOONGARCH_GPR_FP, -run_ctx_off + cookie_off);
>
>         /* arg1: prog */
> -       move_imm(ctx, LOONGARCH_GPR_A0, (const s64)p, false);
> +       move_imm(ctx, LOONGARCH_GPR_A0, (const s64)p);
>         /* arg2: &run_ctx */
>         emit_insn(ctx, addid, LOONGARCH_GPR_A1, LOONGARCH_GPR_FP, -run_ctx_off);
>         ret = emit_call(ctx, (const u64)bpf_trampoline_enter(p));
> @@ -1755,7 +1765,7 @@ static int invoke_bpf_prog(struct jit_ctx *ctx, struct bpf_tramp_image *im,
>         /* arg1: &args_off */
>         emit_insn(ctx, addid, LOONGARCH_GPR_A0, LOONGARCH_GPR_FP, -args_off);
>         if (!p->jited)
> -               move_imm(ctx, LOONGARCH_GPR_A1, (const s64)p->insnsi, false);
> +               move_imm(ctx, LOONGARCH_GPR_A1, (const s64)p->insnsi);
>         ret = emit_call(ctx, (const u64)p->bpf_func);
>         if (ret)
>                 return ret;
> @@ -1772,7 +1782,7 @@ static int invoke_bpf_prog(struct jit_ctx *ctx, struct bpf_tramp_image *im,
>         }
>
>         /* arg1: prog */
> -       move_imm(ctx, LOONGARCH_GPR_A0, (const s64)p, false);
> +       move_imm(ctx, LOONGARCH_GPR_A0, (const s64)p);
>         /* arg2: prog start time */
>         move_reg(ctx, LOONGARCH_GPR_A1, LOONGARCH_GPR_S1);
>         /* arg3: &run_ctx */
> diff --git a/arch/loongarch/net/bpf_jit.h b/arch/loongarch/net/bpf_jit.h
> index bb58c42c2f2a..57a98f8a055b 100644
> --- a/arch/loongarch/net/bpf_jit.h
> +++ b/arch/loongarch/net/bpf_jit.h
> @@ -137,7 +137,7 @@ static inline void move_addr(struct jit_ctx *ctx, enum loongarch_gpr rd, u64 add
>         emit_insn(ctx, lu52id, rd, rd, imm_63_52);
>  }
>
> -static inline void move_imm(struct jit_ctx *ctx, enum loongarch_gpr rd, long imm, bool is32)
> +static inline void move_imm(struct jit_ctx *ctx, enum loongarch_gpr rd, long imm)
>  {
>         long imm_11_0, imm_31_12, imm_51_32, imm_63_52, imm_51_0, imm_51_31;
>
> @@ -150,7 +150,7 @@ static inline void move_imm(struct jit_ctx *ctx, enum loongarch_gpr rd, long imm
>         /* addiw rd, $zero, imm_11_0 */
>         if (is_signed_imm12(imm)) {
>                 emit_insn(ctx, addiw, rd, LOONGARCH_GPR_ZERO, imm);
> -               goto zext;
> +               return;
>         }
>
>         /* ori rd, $zero, imm_11_0 */
> @@ -195,9 +195,6 @@ static inline void move_imm(struct jit_ctx *ctx, enum loongarch_gpr rd, long imm
>                 if (!is_signed_imm52(imm))
>                         emit_insn(ctx, lu52id, rd, rd, imm_63_52);
>         }
> -
> -zext:
> -       emit_zext_32(ctx, rd, is32);
>  }
>
>  static inline void move_reg(struct jit_ctx *ctx, enum loongarch_gpr rd,
> --
> 2.42.0
>