Commit 471f3d4e authored by Puranjay Mohan's avatar Puranjay Mohan Committed by Alexei Starovoitov
Browse files

arm32, bpf: add support for 32-bit offset jmp instruction 



The cpuv4 adds unconditional jump with 32-bit offset where the immediate
field of the instruction is to be used to calculate the jump offset.

BPF_JA | BPF_K | BPF_JMP32 => gotol +imm => PC += imm.

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/20230907230550.1417590-2-puranjay12@gmail.com


Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
parent 9b2b8633

arch/arm/net/bpf_jit_32.c

+7 −2
Original line number Diff line number Diff line
@@ -1761,10 +1761,15 @@ static int build_insn(const struct bpf_insn *insn, struct jit_ctx *ctx) 
		break;

	/* JMP OFF */

	case BPF_JMP | BPF_JA:

	case BPF_JMP32 | BPF_JA:

	{

		if (off == 0)

			break;

		if (BPF_CLASS(code) == BPF_JMP32 && imm != 0)

			jmp_offset = bpf2a32_offset(i + imm, i, ctx);

		else if (BPF_CLASS(code) == BPF_JMP && off != 0)

			jmp_offset = bpf2a32_offset(i + off, i, ctx);

		else

			break;



		check_imm24(jmp_offset);

		emit(ARM_B(jmp_offset), ctx);

		break;