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From: Eduard Zingerman <eddyz87@gmail.com>
To: Alexei Starovoitov <alexei.starovoitov@gmail.com>
Cc: bpf <bpf@vger.kernel.org>, Alexei Starovoitov <ast@kernel.org>,
	Andrii Nakryiko <andrii@kernel.org>,
	Daniel Borkmann <daniel@iogearbox.net>,
	Martin KaFai Lau <martin.lau@linux.dev>,
	Kernel Team <kernel-team@fb.com>,
	Yonghong Song <yonghong.song@linux.dev>,
	Puranjay Mohan <puranjay@kernel.org>,
	"Jose E. Marchesi" <jose.marchesi@oracle.com>
Subject: Re: [RFC bpf-next v2 2/9] bpf: no_caller_saved_registers attribute for helper calls
Date: Tue, 09 Jul 2024 20:06:22 -0700	[thread overview]
Message-ID: <631943a53448547ecff22103ddf0f27a9053ecbd.camel@gmail.com> (raw)
In-Reply-To: <CAADnVQ+10YQwcddP=oE_NyUyr1WkfW9JoeuNQg3pZb9qK6X6Cw@mail.gmail.com>

On Tue, 2024-07-09 at 18:09 -0700, Alexei Starovoitov wrote:

[...]


> somewhere after spill/fill removal subprog->stack_depth
> needs to be adjust to nocsr_stack_off,
> otherwise extra stack space is wasted.
> I couldn't find this logic in the patch.

Such logic is not present.

> Once the adjustment logic is done, pls add a selftest with
> nocsr and may_goto, since may_goto processing is in the same
> do_misc_fixups() loop and it needs to grow the stack while
> spill/fill removal will shrink the stack.

It might be necessary to move the spill/fill removal to a separate
pass exactly because of this dependency.

I'll think about the implementation, but it might be tricky.

  reply	other threads:[~2024-07-10  3:06 UTC|newest]

Thread overview: 36+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-07-04 10:23 [RFC bpf-next v2 0/9] no_caller_saved_registers attribute for helper calls Eduard Zingerman
2024-07-04 10:23 ` [RFC bpf-next v2 1/9] bpf: add a get_helper_proto() utility function Eduard Zingerman
2024-07-09 23:42   ` Andrii Nakryiko
2024-07-10  0:26     ` Eduard Zingerman
2024-07-04 10:23 ` [RFC bpf-next v2 2/9] bpf: no_caller_saved_registers attribute for helper calls Eduard Zingerman
2024-07-09 23:42   ` Andrii Nakryiko
2024-07-10  3:00     ` Eduard Zingerman
2024-07-10  6:01       ` Andrii Nakryiko
2024-07-10  7:57         ` Eduard Zingerman
2024-07-10 15:36           ` Andrii Nakryiko
2024-07-10 16:15             ` Eduard Zingerman
2024-07-10 17:50               ` Andrii Nakryiko
2024-07-10 18:40                 ` Eduard Zingerman
2024-07-10 18:49                   ` Andrii Nakryiko
2024-07-10 19:03                     ` Eduard Zingerman
2024-07-10 19:16                       ` Andrii Nakryiko
2024-07-10 19:07                   ` Alexei Starovoitov
2024-07-10 19:17                     ` Andrii Nakryiko
2024-07-10 19:01             ` Alexei Starovoitov
2024-07-10  9:46     ` Eduard Zingerman
2024-07-10 15:23       ` Andrii Nakryiko
2024-07-10  1:09   ` Alexei Starovoitov
2024-07-10  3:06     ` Eduard Zingerman [this message]
2024-07-04 10:23 ` [RFC bpf-next v2 3/9] bpf, x86, riscv, arm: no_caller_saved_registers for bpf_get_smp_processor_id() Eduard Zingerman
2024-07-04 10:23 ` [RFC bpf-next v2 4/9] selftests/bpf: extract utility function for BPF disassembly Eduard Zingerman
2024-07-09 23:46   ` Andrii Nakryiko
2024-07-04 10:23 ` [RFC bpf-next v2 5/9] selftests/bpf: no need to track next_match_pos in struct test_loader Eduard Zingerman
2024-07-04 10:23 ` [RFC bpf-next v2 6/9] selftests/bpf: extract test_loader->expect_msgs as a data structure Eduard Zingerman
2024-07-04 10:23 ` [RFC bpf-next v2 7/9] selftests/bpf: allow checking xlated programs in verifier_* tests Eduard Zingerman
2024-07-04 10:24 ` [RFC bpf-next v2 8/9] selftests/bpf: __arch_* macro to limit test cases to specific archs Eduard Zingerman
2024-07-09 23:50   ` Andrii Nakryiko
2024-07-04 10:24 ` [RFC bpf-next v2 9/9] selftests/bpf: test no_caller_saved_registers spill/fill removal Eduard Zingerman
2024-07-08 11:44 ` [RFC bpf-next v2 0/9] no_caller_saved_registers attribute for helper calls Puranjay Mohan
2024-07-08 17:29   ` Eduard Zingerman
2024-07-10  1:18 ` Alexei Starovoitov
2024-07-10  3:35   ` Eduard Zingerman

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