[PATCH v2 00/15] init_mm: cleanup ARCH's text/data/brk setup code
Christophe Leroy
christophe.leroy at csgroup.eu
Sun Jun 6 22:48:54 PDT 2021
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.
Christophe
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