From: Peter Zijlstra <peterz@infradead.org>
To: Menglong Dong <menglong8.dong@gmail.com>
Cc: Alexei Starovoitov <alexei.starovoitov@gmail.com>,
bpf <bpf@vger.kernel.org>
Subject: Re: Idea for "function meta"
Date: Fri, 20 Dec 2024 15:00:58 +0100 [thread overview]
Message-ID: <20241220140058.GE17537@noisy.programming.kicks-ass.net> (raw)
In-Reply-To: <CADxym3anLzM6cAkn_z71GDd_VeKiqqk1ts=xuiP7pr4PO6USPA@mail.gmail.com>
On Fri, Dec 20, 2024 at 09:57:22PM +0800, Menglong Dong wrote:
> However, the other 5-bytes will be consumed if CFI_CLANG is
> enabled, and the space is not enough anymore in this case, and
> the insn will be like this:
>
> __cfi_do_test:
> mov (5byte)
> nop nop (2 bytes)
> sarq (9 bytes)
> do_test:
> xxx
>
FineIBT will fully consume those 16 bytes.
Also, text is ROX, you cannot easily write there. Furthermore, writing
non-instructions there will destroy disassemblers ability to make sense
of the memory.
So no, don't do this.
next prev parent reply other threads:[~2024-12-20 14:01 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-12-20 13:57 Idea for "function meta" Menglong Dong
2024-12-20 14:00 ` Peter Zijlstra [this message]
2024-12-25 3:26 ` Menglong Dong
2025-01-03 19:28 ` Alexei Starovoitov
2025-01-07 13:28 ` Menglong Dong
2025-02-07 8:16 ` Menglong Dong
[not found] <CADxym3Yop==sWx2q8448kYkDWcK=P7+fqeZLzyzk8D0GwZEV-A@mail.gmail.com>
[not found] ` <CAADnVQ+1mSHwUK4rZ_mJP7W72iSXgsVfazurYPRGi=3p5aBVdQ@mail.gmail.com>
2024-12-18 3:52 ` Menglong Dong
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