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From: Andreas Schwab <schwab@suse.de>
To: Xi Ruoyao <xry111@xry111.site>
Cc: liuzhensong <liuzhensong@loongson.cn>,  xuchenghua@loongson.cn,
 chenglulu@loongson.cn,  binutils@sourceware.org,  maskray@google.com,
 caiyinyu@loongson.cn,  Huacai Chen <chenhuacai@kernel.org>
Subject: Re: [PATCH] LoongArch: Set defaults to exec stack 0.
References: <20220725022227.16266-1-liuzhensong@loongson.cn>
 <mvmilnlmx6p.fsf@suse.de>
 <4a264fe57282c1a191204775ffe033512240d2eb.camel@xry111.site>
X-Yow: Now, let's SEND OUT for QUICHE!!
Date: Mon, 25 Jul 2022 10:35:09 +0200
In-Reply-To: <4a264fe57282c1a191204775ffe033512240d2eb.camel@xry111.site> (Xi
 Ruoyao's message of "Mon, 25 Jul 2022 16:14:26 +0800")
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On Jul 25 2022, Xi Ruoyao wrote:

> The doc of elf_backend_default_execstack says:
>
>   /* True if an object file lacking a .note.GNU-stack section
>      should be assumed to be requesting exec stack.  At least one
>      other file in the link needs to have a .note.GNU-stack section
>      for a PT_GNU_STACK segment to be created.  */
>
> So I think it only controls the default behavior of bfd library and is
> not related to the kernel?

The kernel always controls the ultimate decision.

It also means that if no input file has a GNU-stack note, no
PT_GNU_STACK segment is created for the output, in which case the kernel
default (which is PF_X for loongarch) applies.

The value of DEFAULT_STACK_PERMS in glibc must also agree with the
kernel.

-- 
Andreas Schwab, SUSE Labs, schwab@suse.de
GPG Key fingerprint = 0196 BAD8 1CE9 1970 F4BE  1748 E4D4 88E3 0EEA B9D7
"And now for something completely different."