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From: Nicholas Dudar <main.kalliope@gmail.com>
To: bot+bpf-ci@kernel.org
Cc: ast@kernel.org, daniel@iogearbox.net, andrii@kernel.org,
	eddyz87@gmail.com,  memxor@gmail.com, deller@gmx.de,
	James.Bottomley@hansenpartnership.com,  bpf@vger.kernel.org,
	linux-parisc@vger.kernel.org,  linux-kernel@vger.kernel.org,
	visitorckw@gmail.com, martin.lau@kernel.org,
	 yonghong.song@linux.dev, clm@meta.com, ihor.solodrai@linux.dev
Subject: Re: [PATCH bpf-next 1/2] bpf, parisc: Add support for BPF_SDIV and BPF_SMOD in the parisc64 JIT
Date: Fri, 17 Jul 2026 16:58:27 -0400	[thread overview]
Message-ID: <CAJZwKkjUR3FLKwY-WBSwFgK_nLrV20nGGtHZOt3Jf6SXpgyurg@mail.gmail.com> (raw)
In-Reply-To: <730b11181226fe2aa47c5add541431bb8bd4b4fa6af6e3b41bd8a09161d2f51c@mail.kernel.org>

On Fri, Jul 17, 2026 at 19:16 UTC, sashiko-bot@kernel.org wrote:
> [High] The patch implements BPF_SDIV and BPF_SMOD for the 64-bit
> PA-RISC JIT but omits the 32-bit JIT, causing signed divisions to be
> silently miscompiled as unsigned.

This is a 2-patch series, and patch 2/2 ("bpf, parisc: Add support for
BPF_SDIV and BPF_SMOD in the parisc32 JIT") is the one that modifies
bpf_jit_comp32.c. It threads is_signed = (insn->off == 1) through
emit_alu_r32()/emit_alu_r64() and uses the $$divI/$$remI signed
millicode (ALU32) and the hppa_sdiv64()/hppa_sdiv64_rem() helpers
(ALU64) on the signed path instead of $$divU/$$remU/hppa_div64().

Patch 1/2 adds those shared helpers in bpf_jit_core.c, which is why it
does not touch bpf_jit_comp32.c. With both patches applied the parisc32
JIT returns the signed result the verifier and interpreter compute; the
ALU32/ALU64 SDIV/SMOD test_bpf cases pass.

Nicholas

  reply	other threads:[~2026-07-17 20:58 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-07-17 19:05 [PATCH bpf-next 0/2] bpf, parisc: Add support for BPF_SDIV and BPF_SMOD in the parisc JITs Nicholas Dudar
2026-07-17 19:05 ` [PATCH bpf-next 1/2] bpf, parisc: Add support for BPF_SDIV and BPF_SMOD in the parisc64 JIT Nicholas Dudar
2026-07-17 19:52   ` bot+bpf-ci
2026-07-17 20:58     ` Nicholas Dudar [this message]
2026-07-17 22:27     ` Nicholas Dudar
2026-07-17 19:05 ` [PATCH bpf-next 2/2] bpf, parisc: Add support for BPF_SDIV and BPF_SMOD in the parisc32 JIT Nicholas Dudar

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