linux-kernel - arch_align_stack() seems useless

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Date:	Mon, 27 Aug 2007 16:08:31 +0200
From:	Franck Bui-Huu <vagabon.xyz@...il.com>
To:	Linux Kernel Mailing List <linux-kernel@...r.kernel.org>
Subject: arch_align_stack() seems useless

Hello folks,

I recently pick up the implementation of arch_align_stack() from x86
architectures to make it available for mips.

But now I just realised that this function seems useless because of
the way it's used.

Currently, this function seems to be only used to randomize the stack
pointer inside a page during an execve() syscall. Only i386, x86_64
and recently mips do that. Here is the code taken from exec.c which
calls it:

	int setup_arg_pages(struct linux_binprm *bprm,
			    unsigned long stack_top,
			    int executable_stack)
	{
		[...]

		stack_top = arch_align_stack(stack_top);
		stack_top = PAGE_ALIGN(stack_top);

		[...]
	}

Since PAGE_ALIGN() is called right after arch_align_stack(), it seems
to me that the call to the latter function is useless...

Am I missing something ?

thanks

		Franck
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