Re: [PATCH RFC 2/2] LoongArch: BPF: Eliminate zero/sign extensions for 32-bit operations

From: Hengqi Chen

Date: Sun Jul 26 2026 - 05:24:05 EST

On Sat, Jul 11, 2026 at 6:17 PM Tiezhu Yang <yangtiezhu@xxxxxxxxxxx> wrote:
>
> Eliminate frequent and redundant zero-extensions and sign-extensions
> for 32-bit operations. This prevents potential functional bugs caused
> by incorrect extension selections and reduces runtime overhead.
>
> For explicit 32-bit zero-extensions (imm == 1), generate a `lu32id`
> instruction to guarantee the zero-extended form when they cannot be
> bypassed by the look-ahead logic.
>
> For other 32-bit arithmetic, emit LoongArch native 32-bit instructions
> which inherently perform hardware-level sign-extension.
>
> For bitwise logical instructions, append `addiw dst, dst, 0` to enforce
> the standard sign-extended form of the result.
>
> For 32-bit signed conditional jumps, remove redundant register copies
> and pre-jump `emit_sext_32` helpers to leverage native branching, as
> operands are now natively sign-extended.
>
> For 32-bit unsigned conditional jumps, use `bstrpickd` to clear the
> upper 32 bits of the operands.
>
> For JSET bit-testing, maintain `addiw t1, t1, 0` in the jmp32 path to
> ensure correctness.
>
> With this patch, deliver an optimal native execution stream and reduce
> the overall JIT image size.
>
> Signed-off-by: Tiezhu Yang <yangtiezhu@xxxxxxxxxxx>
> ---
> arch/loongarch/net/bpf_jit.c | 357 +++++++++++++++++++----------------
> arch/loongarch/net/bpf_jit.h | 25 +--
> 2 files changed, 198 insertions(+), 184 deletions(-)
>
> diff --git a/arch/loongarch/net/bpf_jit.c b/arch/loongarch/net/bpf_jit.c
> index b8cef3ea5c6d..08a5903dd5a3 100644
> --- a/arch/loongarch/net/bpf_jit.c
> +++ b/arch/loongarch/net/bpf_jit.c
> @@ -209,7 +209,7 @@ 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)
> @@ -311,7 +311,6 @@ static int emit_bpf_tail_call(struct jit_ctx *ctx, int insn)
> * goto out;
> */
> tc_ninsn = insn ? ctx->offset[insn+1] - ctx->offset[insn] : ctx->offset[0];
> - emit_zext_32(ctx, a2, true);
>
> off = offsetof(struct bpf_array, map.max_entries);
> emit_insn(ctx, ldwu, t1, a1, off);
> @@ -361,7 +360,7 @@ 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);
> }
>
> @@ -377,7 +376,7 @@ 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);
>
> @@ -434,7 +433,6 @@ static int emit_atomic_rmw(const struct bpf_insn *insn, struct jit_ctx *ctx)
> return -EINVAL;
> }
> emit_insn(ctx, amaddb, src, t1, t3);
> - emit_zext_32(ctx, src, true);
> break;
> case BPF_H:
> if (!cpu_has_lam_bh) {
> @@ -442,11 +440,9 @@ static int emit_atomic_rmw(const struct bpf_insn *insn, struct jit_ctx *ctx)
> return -EINVAL;
> }
> emit_insn(ctx, amaddh, src, t1, t3);
> - emit_zext_32(ctx, src, true);
> break;
> case BPF_W:
> emit_insn(ctx, amaddw, src, t1, t3);
> - emit_zext_32(ctx, src, true);
> break;
> case BPF_DW:
> emit_insn(ctx, amaddd, src, t1, t3);
> @@ -454,28 +450,22 @@ static int emit_atomic_rmw(const struct bpf_insn *insn, struct jit_ctx *ctx)
> }
> break;
> case BPF_AND | BPF_FETCH:
> - if (isdw) {
> + if (isdw)
> emit_insn(ctx, amandd, src, t1, t3);
> - } else {
> + else
> emit_insn(ctx, amandw, src, t1, t3);
> - emit_zext_32(ctx, src, true);
> - }
> break;
> case BPF_OR | BPF_FETCH:
> - if (isdw) {
> + if (isdw)
> emit_insn(ctx, amord, src, t1, t3);
> - } else {
> + else
> emit_insn(ctx, amorw, src, t1, t3);
> - emit_zext_32(ctx, src, true);
> - }
> break;
> case BPF_XOR | BPF_FETCH:
> - if (isdw) {
> + if (isdw)
> emit_insn(ctx, amxord, src, t1, t3);
> - } else {
> + else
> emit_insn(ctx, amxorw, src, t1, t3);
> - emit_zext_32(ctx, src, true);
> - }
> break;
> /* src = atomic_xchg(dst + off, src); */
> case BPF_XCHG:
> @@ -486,7 +476,6 @@ static int emit_atomic_rmw(const struct bpf_insn *insn, struct jit_ctx *ctx)
> return -EINVAL;
> }
> emit_insn(ctx, amswapb, src, t1, t3);
> - emit_zext_32(ctx, src, true);
> break;
> case BPF_H:
> if (!cpu_has_lam_bh) {
> @@ -494,11 +483,9 @@ static int emit_atomic_rmw(const struct bpf_insn *insn, struct jit_ctx *ctx)
> return -EINVAL;
> }
> emit_insn(ctx, amswaph, src, t1, t3);
> - emit_zext_32(ctx, src, true);
> break;
> case BPF_W:
> emit_insn(ctx, amswapw, src, t1, t3);
> - emit_zext_32(ctx, src, true);
> break;
> case BPF_DW:
> emit_insn(ctx, amswapd, src, t1, t3);
> @@ -516,13 +503,10 @@ static int emit_atomic_rmw(const struct bpf_insn *insn, struct jit_ctx *ctx)
> emit_insn(ctx, beq, t3, LOONGARCH_GPR_ZERO, -4);
> } else {
> emit_insn(ctx, llw, r0, t1, 0);
> - emit_zext_32(ctx, t2, true);
> - emit_zext_32(ctx, r0, true);
> emit_insn(ctx, bne, t2, r0, 4);
> move_reg(ctx, t3, src);
> emit_insn(ctx, scw, t3, t1, 0);
> emit_insn(ctx, beq, t3, LOONGARCH_GPR_ZERO, -6);
> - emit_zext_32(ctx, r0, true);
> }
> break;
> default:
> @@ -549,7 +533,7 @@ 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;
> @@ -557,7 +541,7 @@ 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;
> @@ -565,7 +549,7 @@ 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;
> @@ -573,7 +557,7 @@ 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;
> @@ -596,7 +580,7 @@ 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;
> @@ -604,7 +588,7 @@ 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;
> @@ -612,7 +596,7 @@ 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;
> @@ -620,7 +604,7 @@ 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;
> @@ -741,28 +725,32 @@ static int build_insn(const struct bpf_insn *insn, struct jit_ctx *ctx, bool ext
> switch (code) {
> /* dst = src */
> case BPF_ALU | BPF_MOV | BPF_X:
> + if (imm == 1) {
> + emit_insn(ctx, lu32id, reg, 0);

reg ?

> + break;
> + }
> +
> + emit_insn(ctx, addw, dst, src, LOONGARCH_GPR_ZERO);
> + break;
> case BPF_ALU64 | BPF_MOV | BPF_X:
> 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, 1);
> emit_insn(ctx, or, t1, dst, t1);
> move_reg(ctx, dst, t1);
> break;
> }
> +
> switch (off) {
> case 0:
> move_reg(ctx, dst, src);
> - emit_zext_32(ctx, dst, is32);
> break;
> case 8:
> emit_insn(ctx, extwb, dst, src);
> - emit_zext_32(ctx, dst, is32);
> break;
> case 16:
> emit_insn(ctx, extwh, dst, src);
> - emit_zext_32(ctx, dst, is32);
> break;
> case 32:
> emit_insn(ctx, addw, dst, src, LOONGARCH_GPR_ZERO);
> @@ -773,202 +761,234 @@ 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);
> break;
>
> /* dst = dst + src */
> case BPF_ALU | BPF_ADD | BPF_X:
> + emit_insn(ctx, addw, dst, dst, src);
> + break;
> case BPF_ALU64 | BPF_ADD | BPF_X:
> emit_insn(ctx, addd, dst, dst, src);
> - emit_zext_32(ctx, dst, is32);
> break;
>
> /* dst = dst + imm */
> case BPF_ALU | BPF_ADD | BPF_K:
> + if (is_signed_imm12(imm)) {
> + emit_insn(ctx, addiw, dst, dst, imm);
> + } else {
> + move_imm(ctx, t1, imm);
> + emit_insn(ctx, addw, dst, dst, t1);
> + }
> + break;
> case BPF_ALU64 | BPF_ADD | BPF_K:
> if (is_signed_imm12(imm)) {
> emit_insn(ctx, addid, dst, dst, imm);
> } else {
> - move_imm(ctx, t1, imm, is32);
> + move_imm(ctx, t1, imm);
> emit_insn(ctx, addd, dst, dst, t1);
> }
> - emit_zext_32(ctx, dst, is32);
> break;
>
> /* dst = dst - src */
> case BPF_ALU | BPF_SUB | BPF_X:
> + emit_insn(ctx, subw, dst, dst, src);
> + break;
> case BPF_ALU64 | BPF_SUB | BPF_X:
> emit_insn(ctx, subd, dst, dst, src);
> - emit_zext_32(ctx, dst, is32);
> break;
>
> /* dst = dst - imm */
> case BPF_ALU | BPF_SUB | BPF_K:
> + if (is_signed_imm12(-imm)) {
> + emit_insn(ctx, addiw, dst, dst, -imm);
> + } else {
> + move_imm(ctx, t1, imm);
> + emit_insn(ctx, subw, dst, dst, t1);
> + }
> + break;
> case BPF_ALU64 | BPF_SUB | BPF_K:
> if (is_signed_imm12(-imm)) {
> emit_insn(ctx, addid, dst, dst, -imm);
> } else {
> - move_imm(ctx, t1, imm, is32);
> + move_imm(ctx, t1, imm);
> emit_insn(ctx, subd, dst, dst, t1);
> }
> - emit_zext_32(ctx, dst, is32);
> break;
>
> /* dst = dst * src */
> case BPF_ALU | BPF_MUL | BPF_X:
> + emit_insn(ctx, mulw, dst, dst, src);
> + break;
> case BPF_ALU64 | BPF_MUL | BPF_X:
> emit_insn(ctx, muld, dst, dst, src);
> - emit_zext_32(ctx, dst, is32);
> break;
>
> /* dst = dst * imm */
> case BPF_ALU | BPF_MUL | BPF_K:
> + move_imm(ctx, t1, imm);
> + emit_insn(ctx, mulw, dst, dst, t1);
> + break;
> case BPF_ALU64 | BPF_MUL | BPF_K:
> - move_imm(ctx, t1, imm, is32);
> + move_imm(ctx, t1, imm);
> emit_insn(ctx, muld, dst, dst, t1);
> - emit_zext_32(ctx, dst, is32);
> break;
>
> /* dst = dst / src */
> case BPF_ALU | BPF_DIV | BPF_X:
> + if (!off)
> + emit_insn(ctx, divwu, dst, dst, src);
> + else
> + emit_insn(ctx, divw, dst, dst, src);
> + break;
> case BPF_ALU64 | BPF_DIV | BPF_X:
> - if (!off) {
> - emit_zext_32(ctx, dst, is32);
> - move_reg(ctx, t1, src);
> - emit_zext_32(ctx, t1, is32);
> - emit_insn(ctx, divdu, dst, dst, t1);
> - emit_zext_32(ctx, dst, is32);
> - } else {
> - emit_sext_32(ctx, dst, is32);
> - move_reg(ctx, t1, src);
> - emit_sext_32(ctx, t1, is32);
> - emit_insn(ctx, divd, dst, dst, t1);
> - emit_sext_32(ctx, dst, is32);
> - }
> + if (!off)
> + emit_insn(ctx, divdu, dst, dst, src);
> + else
> + emit_insn(ctx, divd, dst, dst, src);
> break;
>
> /* dst = dst / imm */
> case BPF_ALU | BPF_DIV | BPF_K:
> + move_imm(ctx, t1, imm);
> + if (!off)
> + emit_insn(ctx, divwu, dst, dst, t1);
> + else
> + emit_insn(ctx, divw, dst, dst, t1);
> + break;
> case BPF_ALU64 | BPF_DIV | BPF_K:
> - if (!off) {
> - move_imm(ctx, t1, imm, is32);
> - emit_zext_32(ctx, dst, is32);
> + move_imm(ctx, t1, imm);
> + if (!off)
> emit_insn(ctx, divdu, dst, dst, t1);
> - emit_zext_32(ctx, dst, is32);
> - } else {
> - move_imm(ctx, t1, imm, false);
> - emit_sext_32(ctx, t1, is32);
> - emit_sext_32(ctx, dst, is32);
> + else
> emit_insn(ctx, divd, dst, dst, t1);
> - emit_sext_32(ctx, dst, is32);
> - }
> break;
>
> /* dst = dst % src */
> case BPF_ALU | BPF_MOD | BPF_X:
> + if (!off)
> + emit_insn(ctx, modwu, dst, dst, src);
> + else
> + emit_insn(ctx, modw, dst, dst, src);
> + break;
> case BPF_ALU64 | BPF_MOD | BPF_X:
> - if (!off) {
> - emit_zext_32(ctx, dst, is32);
> - move_reg(ctx, t1, src);
> - emit_zext_32(ctx, t1, is32);
> - emit_insn(ctx, moddu, dst, dst, t1);
> - emit_zext_32(ctx, dst, is32);
> - } else {
> - emit_sext_32(ctx, dst, is32);
> - move_reg(ctx, t1, src);
> - emit_sext_32(ctx, t1, is32);
> - emit_insn(ctx, modd, dst, dst, t1);
> - emit_sext_32(ctx, dst, is32);
> - }
> + if (!off)
> + emit_insn(ctx, moddu, dst, dst, src);
> + else
> + emit_insn(ctx, modd, dst, dst, src);
> break;
>
> /* dst = dst % imm */
> case BPF_ALU | BPF_MOD | BPF_K:
> + move_imm(ctx, t1, imm);
> + if (!off)
> + emit_insn(ctx, modwu, dst, dst, t1);
> + else
> + emit_insn(ctx, modw, dst, dst, t1);
> + break;
> case BPF_ALU64 | BPF_MOD | BPF_K:
> - if (!off) {
> - move_imm(ctx, t1, imm, is32);
> - emit_zext_32(ctx, dst, is32);
> + move_imm(ctx, t1, imm);
> + if (!off)
> emit_insn(ctx, moddu, dst, dst, t1);
> - emit_zext_32(ctx, dst, is32);
> - } else {
> - move_imm(ctx, t1, imm, false);
> - emit_sext_32(ctx, t1, is32);
> - emit_sext_32(ctx, dst, is32);
> + else
> emit_insn(ctx, modd, dst, dst, t1);
> - emit_sext_32(ctx, dst, is32);
> - }
> break;
>
> /* dst = -dst */
> case BPF_ALU | BPF_NEG:
> + emit_insn(ctx, subw, dst, LOONGARCH_GPR_ZERO, dst);
> + break;
> case BPF_ALU64 | BPF_NEG:
> emit_insn(ctx, subd, dst, LOONGARCH_GPR_ZERO, dst);
> - emit_zext_32(ctx, dst, is32);
> break;
>
> /* dst = dst & src */
> case BPF_ALU | BPF_AND | BPF_X:
> + emit_insn(ctx, and, dst, dst, src);
> + emit_insn(ctx, addiw, dst, dst, 0);
> + break;
> case BPF_ALU64 | BPF_AND | BPF_X:
> emit_insn(ctx, and, dst, dst, src);
> - emit_zext_32(ctx, dst, is32);
> break;
>
> /* dst = dst & imm */
> case BPF_ALU | BPF_AND | BPF_K:
> + if (is_unsigned_imm12(imm)) {
> + emit_insn(ctx, andi, dst, dst, imm);
> + } else {
> + move_imm(ctx, t1, imm);
> + emit_insn(ctx, and, dst, dst, t1);
> + }
> + emit_insn(ctx, addiw, dst, dst, 0);

break; ?

> case BPF_ALU64 | BPF_AND | BPF_K:
> if (is_unsigned_imm12(imm)) {
> emit_insn(ctx, andi, dst, dst, imm);
> } else {
> - move_imm(ctx, t1, imm, is32);
> + move_imm(ctx, t1, imm);
> emit_insn(ctx, and, dst, dst, t1);
> }
> - emit_zext_32(ctx, dst, is32);
> break;
>
> /* dst = dst | src */
> case BPF_ALU | BPF_OR | BPF_X:
> + emit_insn(ctx, or, dst, dst, src);
> + emit_insn(ctx, addiw, dst, dst, 0);
> + break;
> case BPF_ALU64 | BPF_OR | BPF_X:
> emit_insn(ctx, or, dst, dst, src);
> - emit_zext_32(ctx, dst, is32);
> break;
>
> /* dst = dst | imm */
> case BPF_ALU | BPF_OR | BPF_K:
> + if (is_unsigned_imm12(imm)) {
> + emit_insn(ctx, ori, dst, dst, imm);
> + } else {
> + move_imm(ctx, t1, imm);
> + emit_insn(ctx, or, dst, dst, t1);
> + }
> + emit_insn(ctx, addiw, dst, dst, 0);
> + break;
> case BPF_ALU64 | BPF_OR | BPF_K:
> if (is_unsigned_imm12(imm)) {
> emit_insn(ctx, ori, dst, dst, imm);
> } else {
> - move_imm(ctx, t1, imm, is32);
> + move_imm(ctx, t1, imm);
> emit_insn(ctx, or, dst, dst, t1);
> }
> - emit_zext_32(ctx, dst, is32);
> break;
>
> /* dst = dst ^ src */
> case BPF_ALU | BPF_XOR | BPF_X:
> + emit_insn(ctx, xor, dst, dst, src);
> + emit_insn(ctx, addiw, dst, dst, 0);
> + break;
> case BPF_ALU64 | BPF_XOR | BPF_X:
> emit_insn(ctx, xor, dst, dst, src);
> - emit_zext_32(ctx, dst, is32);
> break;
>
> /* dst = dst ^ imm */
> case BPF_ALU | BPF_XOR | BPF_K:
> + if (is_unsigned_imm12(imm)) {
> + emit_insn(ctx, xori, dst, dst, imm);
> + } else {
> + move_imm(ctx, t1, imm);
> + emit_insn(ctx, xor, dst, dst, t1);
> + }
> + emit_insn(ctx, addiw, dst, dst, 0);
> + break;
> case BPF_ALU64 | BPF_XOR | BPF_K:
> if (is_unsigned_imm12(imm)) {
> emit_insn(ctx, xori, dst, dst, imm);
> } else {
> - move_imm(ctx, t1, imm, is32);
> + move_imm(ctx, t1, imm);
> emit_insn(ctx, xor, dst, dst, t1);
> }
> - emit_zext_32(ctx, dst, is32);
> break;
>
> /* dst = dst << src (logical) */
> case BPF_ALU | BPF_LSH | BPF_X:
> emit_insn(ctx, sllw, dst, dst, src);
> - emit_zext_32(ctx, dst, is32);
> break;
> -
> case BPF_ALU64 | BPF_LSH | BPF_X:
> emit_insn(ctx, slld, dst, dst, src);
> break;
> @@ -976,9 +996,7 @@ static int build_insn(const struct bpf_insn *insn, struct jit_ctx *ctx, bool ext
> /* dst = dst << imm (logical) */
> case BPF_ALU | BPF_LSH | BPF_K:
> emit_insn(ctx, slliw, dst, dst, imm);
> - emit_zext_32(ctx, dst, is32);
> break;
> -
> case BPF_ALU64 | BPF_LSH | BPF_K:
> emit_insn(ctx, sllid, dst, dst, imm);
> break;
> @@ -986,9 +1004,7 @@ static int build_insn(const struct bpf_insn *insn, struct jit_ctx *ctx, bool ext
> /* dst = dst >> src (logical) */
> case BPF_ALU | BPF_RSH | BPF_X:
> emit_insn(ctx, srlw, dst, dst, src);
> - emit_zext_32(ctx, dst, is32);
> break;
> -
> case BPF_ALU64 | BPF_RSH | BPF_X:
> emit_insn(ctx, srld, dst, dst, src);
> break;
> @@ -996,9 +1012,7 @@ static int build_insn(const struct bpf_insn *insn, struct jit_ctx *ctx, bool ext
> /* dst = dst >> imm (logical) */
> case BPF_ALU | BPF_RSH | BPF_K:
> emit_insn(ctx, srliw, dst, dst, imm);
> - emit_zext_32(ctx, dst, is32);
> break;
> -
> case BPF_ALU64 | BPF_RSH | BPF_K:
> emit_insn(ctx, srlid, dst, dst, imm);
> break;
> @@ -1006,9 +1020,7 @@ static int build_insn(const struct bpf_insn *insn, struct jit_ctx *ctx, bool ext
> /* dst = dst >> src (arithmetic) */
> case BPF_ALU | BPF_ARSH | BPF_X:
> emit_insn(ctx, sraw, dst, dst, src);
> - emit_zext_32(ctx, dst, is32);
> break;
> -
> case BPF_ALU64 | BPF_ARSH | BPF_X:
> emit_insn(ctx, srad, dst, dst, src);
> break;
> @@ -1016,9 +1028,7 @@ static int build_insn(const struct bpf_insn *insn, struct jit_ctx *ctx, bool ext
> /* dst = dst >> imm (arithmetic) */
> case BPF_ALU | BPF_ARSH | BPF_K:
> emit_insn(ctx, sraiw, dst, dst, imm);
> - emit_zext_32(ctx, dst, is32);
> break;
> -
> case BPF_ALU64 | BPF_ARSH | BPF_K:
> emit_insn(ctx, sraid, dst, dst, imm);
> break;
> @@ -1031,8 +1041,7 @@ static int build_insn(const struct bpf_insn *insn, struct jit_ctx *ctx, bool ext
> emit_insn(ctx, bstrpickd, dst, dst, 15, 0);
> break;
> case 32:
> - /* zero-extend 32 bits into 64 bits */
> - emit_zext_32(ctx, dst, is32);
> + emit_insn(ctx, addiw, dst, dst, 0);
> break;
> case 64:
> /* do nothing */
> @@ -1050,8 +1059,6 @@ static int build_insn(const struct bpf_insn *insn, struct jit_ctx *ctx, bool ext
> break;
> case 32:
> emit_insn(ctx, revb2w, dst, dst);
> - /* clear the upper 32 bits */
> - emit_zext_32(ctx, dst, true);
> break;
> case 64:
> emit_insn(ctx, revbd, dst, dst);
> @@ -1070,6 +1077,11 @@ static int build_insn(const struct bpf_insn *insn, struct jit_ctx *ctx, bool ext
> case BPF_JMP | BPF_JSGE | BPF_X:
> case BPF_JMP | BPF_JSLT | BPF_X:
> case BPF_JMP | BPF_JSLE | BPF_X:
> + jmp_offset = bpf2la_offset(i, off, ctx);
> + if (emit_cond_jmp(ctx, cond, dst, src, jmp_offset) < 0)
> + goto toofar;
> + break;
> +
> case BPF_JMP32 | BPF_JEQ | BPF_X:
> case BPF_JMP32 | BPF_JNE | BPF_X:
> case BPF_JMP32 | BPF_JGT | BPF_X:
> @@ -1081,17 +1093,15 @@ static int build_insn(const struct bpf_insn *insn, struct jit_ctx *ctx, bool ext
> case BPF_JMP32 | BPF_JSLT | BPF_X:
> case BPF_JMP32 | BPF_JSLE | BPF_X:
> jmp_offset = bpf2la_offset(i, off, ctx);
> - move_reg(ctx, t1, dst);
> - move_reg(ctx, t2, src);
> if (is_signed_bpf_cond(BPF_OP(code))) {
> - emit_sext_32(ctx, t1, is32);
> - emit_sext_32(ctx, t2, is32);
> + if (emit_cond_jmp(ctx, cond, dst, src, jmp_offset) < 0)
> + goto toofar;
> } else {
> - emit_zext_32(ctx, t1, is32);
> - emit_zext_32(ctx, t2, is32);
> + emit_insn(ctx, bstrpickd, t1, dst, 31, 0);
> + emit_insn(ctx, bstrpickd, t2, src, 31, 0);
> + if (emit_cond_jmp(ctx, cond, t1, t2, jmp_offset) < 0)
> + goto toofar;
> }
> - if (emit_cond_jmp(ctx, cond, t1, t2, jmp_offset) < 0)
> - goto toofar;
> break;
>
> /* PC += off if dst cond imm */
> @@ -1105,6 +1115,17 @@ static int build_insn(const struct bpf_insn *insn, struct jit_ctx *ctx, bool ext
> case BPF_JMP | BPF_JSGE | BPF_K:
> case BPF_JMP | BPF_JSLT | BPF_K:
> case BPF_JMP | BPF_JSLE | BPF_K:
> + jmp_offset = bpf2la_offset(i, off, ctx);
> + if (imm) {
> + move_imm(ctx, t1, imm);
> + tm = t1;
> + } else {
> + tm = LOONGARCH_GPR_ZERO;
> + }
> +
> + if (emit_cond_jmp(ctx, cond, dst, tm, jmp_offset) < 0)
> + goto toofar;
> + break;
> case BPF_JMP32 | BPF_JEQ | BPF_K:
> case BPF_JMP32 | BPF_JNE | BPF_K:
> case BPF_JMP32 | BPF_JGT | BPF_K:
> @@ -1117,41 +1138,55 @@ 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. */
> tm = LOONGARCH_GPR_ZERO;
> }
> - move_reg(ctx, t2, dst);
> +
> if (is_signed_bpf_cond(BPF_OP(code))) {
> - emit_sext_32(ctx, tm, is32);
> - emit_sext_32(ctx, t2, is32);
> + if (emit_cond_jmp(ctx, cond, dst, tm, jmp_offset) < 0)
> + goto toofar;
> } else {
> - emit_zext_32(ctx, tm, is32);
> - emit_zext_32(ctx, t2, is32);
> + emit_insn(ctx, bstrpickd, t2, dst, 31, 0);
> + if (imm)
> + emit_insn(ctx, bstrpickd, t1, tm, 31, 0);
> + else
> + t1 = LOONGARCH_GPR_ZERO;
> +
> + if (emit_cond_jmp(ctx, cond, t2, t1, jmp_offset) < 0)
> + goto toofar;
> }
> - if (emit_cond_jmp(ctx, cond, t2, tm, jmp_offset) < 0)
> - goto toofar;
> break;
>
> /* PC += off if dst & src */
> case BPF_JMP | BPF_JSET | BPF_X:
> + jmp_offset = bpf2la_offset(i, off, ctx);
> + emit_insn(ctx, and, t1, dst, src);
> + if (emit_cond_jmp(ctx, cond, t1, LOONGARCH_GPR_ZERO, jmp_offset) < 0)
> + goto toofar;
> + break;
> case BPF_JMP32 | BPF_JSET | BPF_X:
> jmp_offset = bpf2la_offset(i, off, ctx);
> emit_insn(ctx, and, t1, dst, src);
> - emit_zext_32(ctx, t1, is32);
> + emit_insn(ctx, addiw, t1, t1, 0);
> if (emit_cond_jmp(ctx, cond, t1, LOONGARCH_GPR_ZERO, jmp_offset) < 0)
> goto toofar;
> break;
>
> /* PC += off if dst & imm */
> case BPF_JMP | BPF_JSET | BPF_K:
> + jmp_offset = bpf2la_offset(i, off, ctx);
> + move_imm(ctx, t1, imm);
> + emit_insn(ctx, and, t1, dst, t1);
> + if (emit_cond_jmp(ctx, cond, t1, LOONGARCH_GPR_ZERO, jmp_offset) < 0)
> + goto toofar;
> + break;
> 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_insn(ctx, and, t1, dst, t1);
> - emit_zext_32(ctx, t1, is32);
> + emit_insn(ctx, addiw, t1, t1, 0);
> if (emit_cond_jmp(ctx, cond, t1, LOONGARCH_GPR_ZERO, jmp_offset) < 0)
> goto toofar;
> break;
> @@ -1241,7 +1276,7 @@ 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;
> }
>
> @@ -1282,7 +1317,7 @@ 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
> @@ -1296,7 +1331,7 @@ 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
> @@ -1310,7 +1345,7 @@ 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
> @@ -1318,7 +1353,7 @@ 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;
> }
> @@ -1353,42 +1388,42 @@ 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;
> @@ -1419,7 +1454,7 @@ 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;
> @@ -1427,7 +1462,7 @@ 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;
> @@ -1437,7 +1472,7 @@ 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;
> @@ -1447,7 +1482,7 @@ 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;
> @@ -1559,7 +1594,7 @@ 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;
> @@ -1733,7 +1768,7 @@ static int invoke_bpf_prog(struct jit_ctx *ctx, struct bpf_tramp_node *n,
> 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));
> @@ -1754,7 +1789,7 @@ static int invoke_bpf_prog(struct jit_ctx *ctx, struct bpf_tramp_node *n,
> /* 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;
> @@ -1771,7 +1806,7 @@ static int invoke_bpf_prog(struct jit_ctx *ctx, struct bpf_tramp_node *n,
> }
>
> /* 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..2bd0dc5b911c 100644
> --- a/arch/loongarch/net/bpf_jit.h
> +++ b/arch/loongarch/net/bpf_jit.h
> @@ -72,24 +72,6 @@ static inline int epilogue_offset(const struct jit_ctx *ctx)
> return (to - from);
> }
>
> -/* Zero-extend 32 bits into 64 bits */
> -static inline void emit_zext_32(struct jit_ctx *ctx, enum loongarch_gpr reg, bool is32)
> -{
> - if (!is32)
> - return;
> -
> - emit_insn(ctx, lu32id, reg, 0);
> -}
> -
> -/* Signed-extend 32 bits into 64 bits */
> -static inline void emit_sext_32(struct jit_ctx *ctx, enum loongarch_gpr reg, bool is32)
> -{
> - if (!is32)
> - return;
> -
> - emit_insn(ctx, addiw, reg, reg, 0);
> -}
> -
> /* Emit proper extension according to ABI requirements.
> * Note that it requires a value of size `size` already resides in register `reg`.
> */
> @@ -137,7 +119,7 @@ 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 +132,7 @@ 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 +177,6 @@ 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
>
>