To: Amerigo Wang <xiyou.wangcong@gmail.com>
Cc: Tao Ma <tao.ma@oracle.com>, Andrew Morton <akpm@linux-foundation.org>,
       linux-kernel@vger.kernel.org, Alexey Dobriyan <adobriyan@gmail.com>
References: <4A2A7F33.4030807@oracle.com> <4A2AEBE3.4000100@kernel.org>
	<20090608015242.GB2596@cr0.nay.redhat.com>
	<4A2CA96D.3090502@oracle.com>
	<2375c9f90906072341o2cded749m45bdddfdb499469@mail.gmail.com>
	<4A2CC52B.9010602@oracle.com>
	<2375c9f90906081743p77934f47n8ba1a018d333b95b@mail.gmail.com>
	<m1ab4i11zx.fsf@fess.ebiederm.org>
	<20090611050929.GA2706@cr0.nay.redhat.com>
	<m11vpqvozl.fsf@fess.ebiederm.org> <20090613040958.GA2959@cr0>
From: ebiederm@xmission.com (Eric W. Biederman)
Date: Fri, 12 Jun 2009 21:20:50 -0700
In-Reply-To: <20090613040958.GA2959@cr0> (Amerigo Wang's message of "Sat\, 13 Jun 2009 12\:09\:58 +0800")
Message-ID: <m17hzg7oil.fsf@fess.ebiederm.org>
User-Agent: Gnus/5.11 (Gnus v5.11) Emacs/22.2 (gnu/linux)
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Subject: Re: [Patch BUGFIX] kcore: fix its wrong size on x86_64
Sender: linux-kernel-owner@vger.kernel.org
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Amerigo Wang <xiyou.wangcong@gmail.com> writes:

> Fix wrong /proc/kcore size on x86_64.

How does that change anything?

> x86_64 uses __va() macro to caculate the virtual address passed to kclist_add()
> but decodes it with its own macro kc_vadd_to_offset(). This is wrong.
>
> Also, according to Documentation/x86/x86_64/mm.txt, kc_vaddr_to_offset()
> is wrong too.
>
> So just remove them, use the generic macro.
>
> BTW, the man page for /proc/kcore is wrong, its size can be more than
> the physical memory size, because it also contains memory area of
> vmalloc(), vsyscall etc...

The set of offsets that are usable sure.

However the size from stat is:
          proc_root_kcore->size = (size_t)high_memory - PAGE_OFFSET + PAGE_SIZE;

Which can not be different than the physical memory size.

> Reported-by: Tao Ma <tao.ma@oracle.com>
> Signed-off-by: WANG Cong <amwang@redhat.com>
> Cc: Eric W. Biederman <ebiederm@xmission.com>
>
> ---
> diff --git a/arch/x86/include/asm/pgtable_64.h b/arch/x86/include/asm/pgtable_64.h
> index abde308..cdbfd1d 100644
> --- a/arch/x86/include/asm/pgtable_64.h
> +++ b/arch/x86/include/asm/pgtable_64.h
> @@ -163,12 +163,6 @@ extern void cleanup_highmap(void);
>  #define PAGE_AGP    PAGE_KERNEL_NOCACHE
>  #define HAVE_PAGE_AGP 1
>  
> -/* fs/proc/kcore.c */
> -#define	kc_vaddr_to_offset(v) ((v) & __VIRTUAL_MASK)
> -#define	kc_offset_to_vaddr(o)				\
> -	(((o) & (1UL << (__VIRTUAL_MASK_SHIFT - 1)))	\
> -	 ? ((o) | ~__VIRTUAL_MASK)			\
> -	 : (o))
>  
>  #define __HAVE_ARCH_PTE_SAME
>  #endif /* !__ASSEMBLY__ */
--
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