Commit 7111afe8 authored by Hengqi Chen's avatar Hengqi Chen Committed by Huacai Chen
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LoongArch: BPF: Support sign-extension load instructions 



Add support for sign-extension load instructions.

Signed-off-by: default avatarHengqi Chen <hengqi.chen@gmail.com>
Signed-off-by: default avatarHuacai Chen <chenhuacai@loongson.cn>
parent add28024

arch/loongarch/net/bpf_jit.c

+39 −10
Original line number Diff line number Diff line
@@ -411,7 +411,11 @@ static int add_exception_handler(const struct bpf_insn *insn, 
	off_t offset;

	struct exception_table_entry *ex;



	if (!ctx->image || !ctx->prog->aux->extable || BPF_MODE(insn->code) != BPF_PROBE_MEM)

	if (!ctx->image || !ctx->prog->aux->extable)

		return 0;



	if (BPF_MODE(insn->code) != BPF_PROBE_MEM &&

	    BPF_MODE(insn->code) != BPF_PROBE_MEMSX)

		return 0;



	if (WARN_ON_ONCE(ctx->num_exentries >= ctx->prog->aux->num_exentries))
@@ -450,7 +454,7 @@ static int build_insn(const struct bpf_insn *insn, struct jit_ctx *ctx, bool ext 
{

	u8 tm = -1;

	u64 func_addr;

	bool func_addr_fixed;

	bool func_addr_fixed, sign_extend;

	int i = insn - ctx->prog->insnsi;

	int ret, jmp_offset;

	const u8 code = insn->code;
@@ -879,30 +883,55 @@ static int build_insn(const struct bpf_insn *insn, struct jit_ctx *ctx, bool ext 
	case BPF_LDX | BPF_PROBE_MEM | BPF_W:

	case BPF_LDX | BPF_PROBE_MEM | BPF_H:

	case BPF_LDX | BPF_PROBE_MEM | BPF_B:

	/* dst_reg = (s64)*(signed size *)(src_reg + off) */

	case BPF_LDX | BPF_MEMSX | BPF_B:

	case BPF_LDX | BPF_MEMSX | BPF_H:

	case BPF_LDX | BPF_MEMSX | BPF_W:

	case BPF_LDX | BPF_PROBE_MEMSX | BPF_B:

	case BPF_LDX | BPF_PROBE_MEMSX | BPF_H:

	case BPF_LDX | BPF_PROBE_MEMSX | BPF_W:

		sign_extend = BPF_MODE(insn->code) == BPF_MEMSX ||

			      BPF_MODE(insn->code) == BPF_PROBE_MEMSX;

		switch (BPF_SIZE(code)) {

		case BPF_B:

			if (is_signed_imm12(off)) {

				if (sign_extend)

					emit_insn(ctx, ldb, dst, src, off);

				else

					emit_insn(ctx, ldbu, dst, src, off);

			} else {

				move_imm(ctx, t1, off, is32);

				if (sign_extend)

					emit_insn(ctx, ldxb, dst, src, t1);

				else

					emit_insn(ctx, ldxbu, dst, src, t1);

			}

			break;

		case BPF_H:

			if (is_signed_imm12(off)) {

				if (sign_extend)

					emit_insn(ctx, ldh, dst, src, off);

				else

					emit_insn(ctx, ldhu, dst, src, off);

			} else {

				move_imm(ctx, t1, off, is32);

				if (sign_extend)

					emit_insn(ctx, ldxh, dst, src, t1);

				else

					emit_insn(ctx, ldxhu, dst, src, t1);

			}

			break;

		case BPF_W:

			if (is_signed_imm12(off)) {

				if (sign_extend)

					emit_insn(ctx, ldw, dst, src, off);

				else

					emit_insn(ctx, ldwu, dst, src, off);

			} else if (is_signed_imm14(off)) {

				emit_insn(ctx, ldptrw, dst, src, off);

			} else {

				move_imm(ctx, t1, off, is32);

				if (sign_extend)

					emit_insn(ctx, ldxw, dst, src, t1);

				else

					emit_insn(ctx, ldxwu, dst, src, t1);

			}

			break;