Commit 1cfb7eae authored by Puranjay Mohan's avatar Puranjay Mohan Committed by Alexei Starovoitov
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arm32, bpf: add support for unconditional bswap instruction 



The cpuv4 added a new unconditional bswap instruction with following
behaviour:

BPF_ALU64 | BPF_TO_LE | BPF_END with imm = 16/32/64 means:
dst = bswap16(dst)
dst = bswap32(dst)
dst = bswap64(dst)

As we already support converting to big-endian from little-endian we can
use the same for unconditional bswap. just treat the unconditional scenario
the same as big-endian conversion.

Signed-off-by: default avatarPuranjay Mohan <puranjay12@gmail.com>
Reviewed-by: default avatarRussell King (Oracle) <rmk+kernel@armlinux.org.uk>
Link: https://lore.kernel.org/r/20230907230550.1417590-5-puranjay12@gmail.com


Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
parent fc832653

arch/arm/net/bpf_jit_32.c

+5 −3
Original line number Diff line number Diff line
@@ -1635,10 +1635,12 @@ static int build_insn(const struct bpf_insn *insn, struct jit_ctx *ctx) 
		break;

	/* dst = htole(dst) */

	/* dst = htobe(dst) */

	case BPF_ALU | BPF_END | BPF_FROM_LE:

	case BPF_ALU | BPF_END | BPF_FROM_BE:

	case BPF_ALU | BPF_END | BPF_FROM_LE: /* also BPF_TO_LE */

	case BPF_ALU | BPF_END | BPF_FROM_BE: /* also BPF_TO_BE */

	/* dst = bswap(dst) */

	case BPF_ALU64 | BPF_END | BPF_FROM_LE: /* also BPF_TO_LE */

		rd = arm_bpf_get_reg64(dst, tmp, ctx);

		if (BPF_SRC(code) == BPF_FROM_LE)

		if (BPF_SRC(code) == BPF_FROM_LE && BPF_CLASS(code) != BPF_ALU64)

			goto emit_bswap_uxt;

		switch (imm) {

		case 16: