[PATCH v2 00/15] init_mm: cleanup ARCH's text/data/brk setup code
Kefeng Wang
wangkefeng.wang at huawei.com
Mon Jun 7 01:30:40 PDT 2021
On 2021/6/7 13:48, Christophe Leroy wrote:
> Hi Kefeng,
>
> Le 07/06/2021 à 02:55, Kefeng Wang a écrit :
>>
>> On 2021/6/7 5:29, Mike Rapoport wrote:
>>> Hello Kefeng,
>>>
>>> On Fri, Jun 04, 2021 at 03:06:18PM +0800, Kefeng Wang wrote:
>>>> Add setup_initial_init_mm() helper, then use it
>>>> to cleanup the text, data and brk setup code.
>>>>
>>>> v2:
>>>> - change argument from "char *" to "void *" setup_initial_init_mm()
>>>> suggested by Geert Uytterhoeven
>>>> - use NULL instead of (void *)0 on h8300 and m68k
>>>> - collect ACKs
>>>>
>>>> Cc: linux-snps-arc at lists.infradead.org
>>>> Cc: linux-arm-kernel at lists.infradead.org
>>>> Cc: linux-csky at vger.kernel.org
>>>> Cc: uclinux-h8-devel at lists.sourceforge.jp
>>>> Cc: linux-m68k at lists.linux-m68k.org
>>>> Cc: openrisc at lists.librecores.org
>>>> Cc: linuxppc-dev at lists.ozlabs.org
>>>> Cc: linux-riscv at lists.infradead.org
>>>> Cc: linux-sh at vger.kernel.org
>>>> Cc: linux-s390 at vger.kernel.org
>>>> Kefeng Wang (15):
>>>> mm: add setup_initial_init_mm() helper
>>>> arc: convert to setup_initial_init_mm()
>>>> arm: convert to setup_initial_init_mm()
>>>> arm64: convert to setup_initial_init_mm()
>>>> csky: convert to setup_initial_init_mm()
>>>> h8300: convert to setup_initial_init_mm()
>>>> m68k: convert to setup_initial_init_mm()
>>>> nds32: convert to setup_initial_init_mm()
>>>> nios2: convert to setup_initial_init_mm()
>>>> openrisc: convert to setup_initial_init_mm()
>>>> powerpc: convert to setup_initial_init_mm()
>>>> riscv: convert to setup_initial_init_mm()
>>>> s390: convert to setup_initial_init_mm()
>>>> sh: convert to setup_initial_init_mm()
>>>> x86: convert to setup_initial_init_mm()
>>> I might be missing something, but AFAIU the init_mm.start_code and
>>> other
>>> fields are not used really early so the new setup_initial_init_mm()
>>> function can be called in the generic code outside setup_arch(), e.g in
>>> mm_init().
>>
>> Hi Mike, each architecture has their own value, not the same, eg m68K
>> and
>>
>> h8300, also the name of the text/code/brk is different in some arch,
>> so I keep
>>
>> unchanged.
>
> What you could do is to define a __weak function that architectures
> can override and call that function from mm_init() as suggested by Mike,
>
> Something like:
>
> void __weak setup_initial_init_mm(void)
> {
> init_mm.start_code = (unsigned long)_stext;
> init_mm.end_code = (unsigned long)_etext;
> init_mm.end_data = (unsigned long)_edata;
> init_mm.brk = (unsigned long)_end;
> }
>
> Then only the few architecture that are different would override it.
>
> I see a few archictectures are usigne PAGE_OFFSET to set .start_code,
> but it is likely that this is equivalent to _stext.
Yes, the __weak function is option, but the change is only covered 14
archs, there are 7 other archs(alpha hexagon ia64
microblaze mips sparc um xtensa)without related setup code. Also like
x86, it has own brk , maybe there are some
other different in some arch, so I think let's keep unchanged for now,
thanks.
>
> Christophe
> .
>
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