From: "Alexei Starovoitov" <alexei.starovoitov@gmail.com>
To: "Yonghong Song" <yonghong.song@linux.dev>, <bpf@vger.kernel.org>
Cc: "Alexei Starovoitov" <ast@kernel.org>,
"Andrii Nakryiko" <andrii@kernel.org>,
"Daniel Borkmann" <daniel@iogearbox.net>,
"Jose E . Marchesi" <jose.marchesi@oracle.com>,
<kernel-team@fb.com>, "Martin KaFai Lau" <martin.lau@kernel.org>,
"Puranjay Mohan" <puranjay@kernel.org>
Subject: Re: [PATCH bpf-next v2 21/23] bpf, arm64: Map BPF_REG_0 to x8 instead of x7
Date: Fri, 08 May 2026 11:01:51 -0700 [thread overview]
Message-ID: <DIDHQFKDC6HH.4WI1HOEQ6HT5@gmail.com> (raw)
In-Reply-To: <20260507213156.1139442-1-yonghong.song@linux.dev>
On Thu May 7, 2026 at 2:31 PM PDT, Yonghong Song wrote:
> From: Puranjay Mohan <puranjay@kernel.org>
>
> Move the BPF return value register from x7 to x8, freeing x7 for use
> as an argument register. AAPCS64 designates x8 as the indirect result
> location register; it is caller-saved and not used for argument
> passing, making it a suitable home for BPF_REG_0.
>
> This is a prerequisite for stack argument support, which needs x5-x7
> to pass arguments 6-8 to native kfuncs following the AAPCS64 calling
> convention.
>
> Signed-off-by: Yonghong Song <yonghong.song@linux.dev>
> Signed-off-by: Yonghong Song <yonghong.song@linux.dev>
That's not right.
It should probably be:
Signed-off-by: Puranjay Mohan <puranjay@kernel.org>
Signed-off-by: Yonghong Song <yonghong.song@linux.dev>
next prev parent reply other threads:[~2026-05-08 18:01 UTC|newest]
Thread overview: 68+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-05-07 21:29 [PATCH bpf-next v2 00/23] bpf: Support stack arguments for BPF functions and kfuncs Yonghong Song
2026-05-07 21:29 ` [PATCH bpf-next v2 01/23] bpf: Convert bpf_get_spilled_reg macro to static inline function Yonghong Song
2026-05-07 21:29 ` [PATCH bpf-next v2 02/23] bpf: Remove copy_register_state wrapper function Yonghong Song
2026-05-07 21:29 ` [PATCH bpf-next v2 03/23] bpf: Add helper functions for r11-based stack argument insns Yonghong Song
2026-05-07 21:30 ` [PATCH bpf-next v2 04/23] bpf: Set sub->arg_cnt earlier in btf_prepare_func_args() Yonghong Song
2026-05-07 22:11 ` bot+bpf-ci
2026-05-09 13:05 ` Yonghong Song
2026-05-07 21:30 ` [PATCH bpf-next v2 05/23] bpf: Support stack arguments for bpf functions Yonghong Song
2026-05-07 22:26 ` bot+bpf-ci
2026-05-09 12:52 ` Yonghong Song
2026-05-08 18:00 ` Alexei Starovoitov
2026-05-09 12:55 ` Yonghong Song
2026-05-07 21:30 ` [PATCH bpf-next v2 06/23] bpf: Refactor jmp history to use dedicated spi/frame fields Yonghong Song
2026-05-07 21:30 ` [PATCH bpf-next v2 07/23] bpf: Add precision marking and backtracking for stack argument slots Yonghong Song
2026-05-07 22:11 ` bot+bpf-ci
2026-05-09 13:08 ` Yonghong Song
2026-05-09 4:05 ` sashiko-bot
2026-05-10 16:41 ` Yonghong Song
2026-05-07 21:30 ` [PATCH bpf-next v2 08/23] bpf: Refactor record_call_access() to extract per-arg logic Yonghong Song
2026-05-07 21:30 ` [PATCH bpf-next v2 09/23] bpf: Extend liveness analysis to track stack argument slots Yonghong Song
2026-05-07 22:11 ` bot+bpf-ci
2026-05-09 13:29 ` Yonghong Song
2026-05-09 0:59 ` sashiko-bot
2026-05-10 16:47 ` Yonghong Song
2026-05-07 21:30 ` [PATCH bpf-next v2 10/23] bpf: Reject stack arguments in non-JITed programs Yonghong Song
2026-05-07 22:11 ` bot+bpf-ci
2026-05-09 2:10 ` sashiko-bot
2026-05-10 16:59 ` Yonghong Song
2026-05-07 21:30 ` [PATCH bpf-next v2 11/23] bpf: Prepare architecture JIT support for stack arguments Yonghong Song
2026-05-09 2:19 ` sashiko-bot
2026-05-10 17:05 ` Yonghong Song
2026-05-07 21:30 ` [PATCH bpf-next v2 12/23] bpf: Enable r11 based insns Yonghong Song
2026-05-09 2:59 ` sashiko-bot
2026-05-10 17:11 ` Yonghong Song
2026-05-07 21:30 ` [PATCH bpf-next v2 13/23] bpf: Support stack arguments for kfunc calls Yonghong Song
2026-05-07 21:30 ` [PATCH bpf-next v2 14/23] bpf: Reject stack arguments if tail call reachable Yonghong Song
2026-05-07 22:11 ` bot+bpf-ci
2026-05-09 1:42 ` sashiko-bot
2026-05-10 17:15 ` Yonghong Song
2026-05-07 21:30 ` [PATCH bpf-next v2 15/23] bpf,x86: Implement JIT support for stack arguments Yonghong Song
2026-05-07 22:26 ` bot+bpf-ci
2026-05-10 17:21 ` Yonghong Song
2026-05-09 2:21 ` sashiko-bot
2026-05-10 17:22 ` Yonghong Song
2026-05-07 21:31 ` [PATCH bpf-next v2 16/23] selftests/bpf: Add tests for BPF function " Yonghong Song
2026-05-07 21:31 ` [PATCH bpf-next v2 17/23] selftests/bpf: Add tests for stack argument validation Yonghong Song
2026-05-09 1:30 ` sashiko-bot
2026-05-10 17:23 ` Yonghong Song
2026-05-07 21:31 ` [PATCH bpf-next v2 18/23] selftests/bpf: Add BTF fixup for __naked subprog parameter names Yonghong Song
2026-05-09 1:40 ` sashiko-bot
2026-05-10 17:24 ` Yonghong Song
2026-05-07 21:31 ` [PATCH bpf-next v2 19/23] selftests/bpf: Add verifier tests for stack argument validation Yonghong Song
2026-05-07 22:11 ` bot+bpf-ci
2026-05-10 17:27 ` Yonghong Song
2026-05-09 1:38 ` sashiko-bot
2026-05-10 17:27 ` Yonghong Song
2026-05-07 21:31 ` [PATCH bpf-next v2 20/23] selftests/bpf: Add precision backtracking test for stack arguments Yonghong Song
2026-05-09 1:52 ` sashiko-bot
2026-05-10 17:31 ` Yonghong Song
2026-05-07 21:31 ` [PATCH bpf-next v2 21/23] bpf, arm64: Map BPF_REG_0 to x8 instead of x7 Yonghong Song
2026-05-08 18:01 ` Alexei Starovoitov [this message]
2026-05-09 13:44 ` Yonghong Song
2026-05-07 21:32 ` [PATCH bpf-next v2 22/23] bpf, arm64: Add JIT support for stack arguments Yonghong Song
2026-05-09 2:15 ` sashiko-bot
2026-05-10 17:32 ` Yonghong Song
2026-05-07 21:32 ` [PATCH bpf-next v2 23/23] selftests/bpf: Enable stack argument tests for arm64 Yonghong Song
2026-05-08 18:06 ` [PATCH bpf-next v2 00/23] bpf: Support stack arguments for BPF functions and kfuncs Alexei Starovoitov
2026-05-09 13:43 ` Yonghong Song
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