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

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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: Puranjay Mohan <puranjay12@gmail.com>
Reviewed-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
Link: https://lore.kernel.org/r/20230907230550.1417590-2-puranjay12@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
This commit is contained in:
Puranjay Mohan 2023-09-07 23:05:42 +00:00 committed by Alexei Starovoitov
parent 9b2b86332a
commit 471f3d4ee4
1 changed files with 7 additions and 2 deletions
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9
arch/arm/net/bpf_jit_32.c
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@ -1761,10 +1761,15 @@ go_jmp:
break;
/* JMP OFF */
case BPF_JMP | BPF_JA:
case BPF_JMP32 | BPF_JA:
{
if (off == 0)
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;
jmp_offset = bpf2a32_offset(i+off, i, ctx);
check_imm24(jmp_offset);
emit(ARM_B(jmp_offset), ctx);
break;