linux-kernel - Re: [PATCH tip] x86/mm: Correct fixmap header usage on adaptable MODULES

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Message-ID: <20170320011408.GA28871@WeideMacBook-Pro.local>
Date:   Mon, 20 Mar 2017 09:14:08 +0800
From:   Wei Yang <richard.weiyang@...il.com>
To:     Thomas Garnier <thgarnie@...gle.com>
Cc:     Wei Yang <richard.weiyang@...il.com>,
        Ingo Molnar <mingo@...hat.com>,
        Andrew Morton <akpm@...ux-foundation.org>,
        the arch/x86 maintainers <x86@...nel.org>,
        LKML <linux-kernel@...r.kernel.org>,
        Linux-MM <linux-mm@...ck.org>
Subject: Re: [PATCH tip] x86/mm: Correct fixmap header usage on adaptable
 MODULES_END

On Sun, Mar 19, 2017 at 09:25:00AM -0700, Thomas Garnier wrote:
>On Sun, Mar 19, 2017 at 9:03 AM, Wei Yang <richard.weiyang@...il.com> wrote:
>> On Fri, Mar 17, 2017 at 10:50:34AM -0700, Thomas Garnier wrote:
>>>This patch remove fixmap header usage on non-x86 code that was
>>>introduced by the adaptable MODULE_END change.
>>
>> Hi, Thomas
>>
>> In this patch, it looks you are trying to do two things for my understanding:
>> 1. To include <asm/fixmap.h> in asm/pagetable_64.h and remove the include in
>> some of the x86 files
>> 2. Remove <asm/fixmap.h> in mm/vmalloc.c
>>
>> I think your change log covers the second task in the patch, but not not talk
>> about the first task you did in the patch. If you could mention it in commit
>> log, it would be good for maintain.
>
>I agree, I am not the best at writing commits (by far). What's the
>best way for me to correct that? (the bot seem to have taken it).
>

Simply mention it in your commit log is enough to me.

>>
>> BTW, I have little knowledge about MODULE_END. By searching the code
>> MODULE_END is not used in arch/x86. If you would like to mention the commit
>> which introduce the problem, it would be more helpful to review the code.
>
>It is used in many places in arch/x86, kasan, head64, fault etc..:
>http://lxr.free-electrons.com/ident?i=MODULES_END
>

Oh, thanks :-)

>>
>>>
>>>Signed-off-by: Thomas Garnier <thgarnie@...gle.com>
>>>---
>>>Based on tip:x86/mm
>>>---
>>> arch/x86/include/asm/pgtable_64.h | 1 +
>>> arch/x86/kernel/module.c          | 1 -
>>> arch/x86/mm/dump_pagetables.c     | 1 -
>>> arch/x86/mm/kasan_init_64.c       | 1 -
>>> mm/vmalloc.c                      | 4 ----
>>> 5 files changed, 1 insertion(+), 7 deletions(-)
>>>
>>>diff --git a/arch/x86/include/asm/pgtable_64.h b/arch/x86/include/asm/pgtable_64.h
>>>index 73c7ccc38912..67608d4abc2c 100644
>>>--- a/arch/x86/include/asm/pgtable_64.h
>>>+++ b/arch/x86/include/asm/pgtable_64.h
>>>@@ -13,6 +13,7 @@
>>> #include <asm/processor.h>
>>> #include <linux/bitops.h>
>>> #include <linux/threads.h>
>>>+#include <asm/fixmap.h>
>>>
>>
>> Hmm... I see in both pgtable_32.h and pgtable_64.h will include <asm/fixmap.h>
>> after this change. And pgtable_32.h and pgtable_64.h will be included only in
>> pgtable.h. So is it possible to include <asm/fixmap.h> in pgtable.h for once
>> instead of include it in both files? Any concerns you would have?
>
>I am not sure I understood. Only 64-bit need this header to correctly
>get MODULES_END, that's why I added it to pgtable_64.h only. I tried
>to add it lower before and ran into multiple header errors.
>

When you look in to pgtable_64.h, you would see it includes <asm/fixmap.h>
too. Hmm... If only 64-bit need this header, would it be possible to remote it
from pgtable_32.h?


>>
>>> extern pud_t level3_kernel_pgt[512];
>>> extern pud_t level3_ident_pgt[512];
>>>diff --git a/arch/x86/kernel/module.c b/arch/x86/kernel/module.c
>>>index fad61caac75e..477ae806c2fa 100644
>>>--- a/arch/x86/kernel/module.c
>>>+++ b/arch/x86/kernel/module.c
>>>@@ -35,7 +35,6 @@
>>> #include <asm/page.h>
>>> #include <asm/pgtable.h>
>>> #include <asm/setup.h>
>>>-#include <asm/fixmap.h>
>>>
>>> #if 0
>>> #define DEBUGP(fmt, ...)                              \
>>>diff --git a/arch/x86/mm/dump_pagetables.c b/arch/x86/mm/dump_pagetables.c
>>>index 75efeecc85eb..58b5bee7ea27 100644
>>>--- a/arch/x86/mm/dump_pagetables.c
>>>+++ b/arch/x86/mm/dump_pagetables.c
>>>@@ -20,7 +20,6 @@
>>>
>>> #include <asm/kasan.h>
>>> #include <asm/pgtable.h>
>>>-#include <asm/fixmap.h>
>>>
>>> /*
>>>  * The dumper groups pagetable entries of the same type into one, and for
>>>diff --git a/arch/x86/mm/kasan_init_64.c b/arch/x86/mm/kasan_init_64.c
>>>index 1bde19ef86bd..8d63d7a104c3 100644
>>>--- a/arch/x86/mm/kasan_init_64.c
>>>+++ b/arch/x86/mm/kasan_init_64.c
>>>@@ -9,7 +9,6 @@
>>>
>>> #include <asm/tlbflush.h>
>>> #include <asm/sections.h>
>>>-#include <asm/fixmap.h>
>>>
>>> extern pgd_t early_level4_pgt[PTRS_PER_PGD];
>>> extern struct range pfn_mapped[E820_X_MAX];
>>>diff --git a/mm/vmalloc.c b/mm/vmalloc.c
>>>index b7d2a23349f4..0dd80222b20b 100644
>>>--- a/mm/vmalloc.c
>>>+++ b/mm/vmalloc.c
>>>@@ -36,10 +36,6 @@
>>> #include <asm/tlbflush.h>
>>> #include <asm/shmparam.h>
>>>
>>>-#ifdef CONFIG_X86
>>>-# include <asm/fixmap.h>
>>>-#endif
>>>-
>>> #include "internal.h"
>>>
>>> struct vfree_deferred {
>>>--
>>>2.12.0.367.g23dc2f6d3c-goog
>>
>> --
>> Wei Yang
>> Help you, Help me
>
>
>
>-- 
>Thomas

-- 
Wei Yang
Help you, Help me

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