Commit 0845c3db authored by Yonghong Song's avatar Yonghong Song Committed by Alexei Starovoitov
Browse files

bpf: Support new unconditional bswap instruction 



The existing 'be' and 'le' insns will do conditional bswap
depends on host endianness. This patch implements
unconditional bswap insns.

Acked-by: default avatarEduard Zingerman <eddyz87@gmail.com>
Signed-off-by: default avatarYonghong Song <yonghong.song@linux.dev>
Link: https://lore.kernel.org/r/20230728011213.3712808-1-yonghong.song@linux.dev


Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
parent 1f1e864b

arch/x86/net/bpf_jit_comp.c

+1 −0
Original line number Diff line number Diff line
@@ -1322,6 +1322,7 @@ static int do_jit(struct bpf_prog *bpf_prog, int *addrs, u8 *image, u8 *rw_image 
			break;



		case BPF_ALU | BPF_END | BPF_FROM_BE:

		case BPF_ALU64 | BPF_END | BPF_FROM_LE:

			switch (imm32) {

			case 16:

				/* Emit 'ror %ax, 8' to swap lower 2 bytes */

kernel/bpf/core.c

+14 −0
Original line number Diff line number Diff line
@@ -1524,6 +1524,7 @@ EXPORT_SYMBOL_GPL(__bpf_call_base); 
	INSN_3(ALU64, DIV,  X),			\

	INSN_3(ALU64, MOD,  X),			\

	INSN_2(ALU64, NEG),			\

	INSN_3(ALU64, END, TO_LE),		\

	/*   Immediate based. */		\

	INSN_3(ALU64, ADD,  K),			\

	INSN_3(ALU64, SUB,  K),			\
@@ -1848,6 +1849,19 @@ static u64 ___bpf_prog_run(u64 *regs, const struct bpf_insn *insn) 
			break;

		}

		CONT;

	ALU64_END_TO_LE:

		switch (IMM) {

		case 16:

			DST = (__force u16) __swab16(DST);

			break;

		case 32:

			DST = (__force u32) __swab32(DST);

			break;

		case 64:

			DST = (__force u64) __swab64(DST);

			break;

		}

		CONT;



	/* CALL */

	JMP_CALL:

kernel/bpf/verifier.c

+5 −2
Original line number Diff line number Diff line
@@ -3012,8 +3012,10 @@ static bool is_reg64(struct bpf_verifier_env *env, struct bpf_insn *insn, 
		}

	}









	if (class == BPF_ALU64 && op == BPF_END && (insn->imm == 16 || insn->imm == 32))









		return false;

















	if (class == BPF_ALU64 || class == BPF_JMP ||









	    /* BPF_END always use BPF_ALU class. */









	    (class == BPF_ALU && op == BPF_END && insn->imm == 64))









		return true;
















@@ -13076,7 +13078,8 @@ static int check_alu_op(struct bpf_verifier_env *env, struct bpf_insn *insn)







		} else {









			if (insn->src_reg != BPF_REG_0 || insn->off != 0 ||









			    (insn->imm != 16 && insn->imm != 32 && insn->imm != 64) ||









			    BPF_CLASS(insn->code) == BPF_ALU64) {









			    (BPF_CLASS(insn->code) == BPF_ALU64 &&









			     BPF_SRC(insn->code) != BPF_TO_LE)) {









				verbose(env, "BPF_END uses reserved fields\n");









				return -EINVAL;









			}