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Re: [Patch V6 12/16] mm: provide early_memremap_ro to establish read-only mapping

From Juergen Gross <jgross@suse.com>
Newsgroups linux.kernel
Subject Re: [Patch V6 12/16] mm: provide early_memremap_ro to establish read-only mapping
Date 2015-08-05 13:20 +0200
Message-ID <pU4TL-85f-1@gated-at.bofh.it> (permalink)
References <pN5UC-3zO-11@gated-at.bofh.it> <pN5UC-3zO-9@gated-at.bofh.it> <pOxF7-6iR-7@gated-at.bofh.it> <pRvQu-3ZS-7@gated-at.bofh.it>
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MM maintainers,

is it really so hard to comment on this patch?


Juergen

On 07/29/2015 11:20 AM, Juergen Gross wrote:
> On 07/21/2015 06:49 AM, Juergen Gross wrote:
>> Hi MM maintainers,
>>
>> this patch is the last requiring an ack for the series to go in.
>> Could you please comment?
>
> PING?
>
>>
>>
>> Juergen
>>
>> On 07/17/2015 06:51 AM, Juergen Gross wrote:
>>> During early boot as Xen pv domain the kernel needs to map some page
>>> tables supplied by the hypervisor read only. This is needed to be
>>> able to relocate some data structures conflicting with the physical
>>> memory map especially on systems with huge RAM (above 512GB).
>>>
>>> Provide the function early_memremap_ro() to provide this read only
>>> mapping.
>>>
>>> Signed-off-by: Juergen Gross <jgross@suse.com>
>>> Acked-by: Konrad Rzeszutek Wilk <Konrad.wilk@oracle.com>
>>> Cc: Arnd Bergmann <arnd@arndb.de>
>>> Cc: linux-mm@kvack.org
>>> Cc: linux-arch@vger.kernel.org
>>> ---
>>>   include/asm-generic/early_ioremap.h |  2 ++
>>>   include/asm-generic/fixmap.h        |  3 +++
>>>   mm/early_ioremap.c                  | 12 ++++++++++++
>>>   3 files changed, 17 insertions(+)
>>>
>>> diff --git a/include/asm-generic/early_ioremap.h
>>> b/include/asm-generic/early_ioremap.h
>>> index a5de55c..316bd04 100644
>>> --- a/include/asm-generic/early_ioremap.h
>>> +++ b/include/asm-generic/early_ioremap.h
>>> @@ -11,6 +11,8 @@ extern void __iomem *early_ioremap(resource_size_t
>>> phys_addr,
>>>                      unsigned long size);
>>>   extern void *early_memremap(resource_size_t phys_addr,
>>>                   unsigned long size);
>>> +extern void *early_memremap_ro(resource_size_t phys_addr,
>>> +                   unsigned long size);
>>>   extern void early_iounmap(void __iomem *addr, unsigned long size);
>>>   extern void early_memunmap(void *addr, unsigned long size);
>>>
>>> diff --git a/include/asm-generic/fixmap.h b/include/asm-generic/fixmap.h
>>> index f23174f..1cbb833 100644
>>> --- a/include/asm-generic/fixmap.h
>>> +++ b/include/asm-generic/fixmap.h
>>> @@ -46,6 +46,9 @@ static inline unsigned long virt_to_fix(const
>>> unsigned long vaddr)
>>>   #ifndef FIXMAP_PAGE_NORMAL
>>>   #define FIXMAP_PAGE_NORMAL PAGE_KERNEL
>>>   #endif
>>> +#if !defined(FIXMAP_PAGE_RO) && defined(PAGE_KERNEL_RO)
>>> +#define FIXMAP_PAGE_RO PAGE_KERNEL_RO
>>> +#endif
>>>   #ifndef FIXMAP_PAGE_NOCACHE
>>>   #define FIXMAP_PAGE_NOCACHE PAGE_KERNEL_NOCACHE
>>>   #endif
>>> diff --git a/mm/early_ioremap.c b/mm/early_ioremap.c
>>> index e10ccd2..0cfadaf 100644
>>> --- a/mm/early_ioremap.c
>>> +++ b/mm/early_ioremap.c
>>> @@ -217,6 +217,13 @@ early_memremap(resource_size_t phys_addr,
>>> unsigned long size)
>>>       return (__force void *)__early_ioremap(phys_addr, size,
>>>                              FIXMAP_PAGE_NORMAL);
>>>   }
>>> +#ifdef FIXMAP_PAGE_RO
>>> +void __init *
>>> +early_memremap_ro(resource_size_t phys_addr, unsigned long size)
>>> +{
>>> +    return (__force void *)__early_ioremap(phys_addr, size,
>>> FIXMAP_PAGE_RO);
>>> +}
>>> +#endif
>>>   #else /* CONFIG_MMU */
>>>
>>>   void __init __iomem *
>>> @@ -231,6 +238,11 @@ early_memremap(resource_size_t phys_addr,
>>> unsigned long size)
>>>   {
>>>       return (void *)phys_addr;
>>>   }
>>> +void __init *
>>> +early_memremap_ro(resource_size_t phys_addr, unsigned long size)
>>> +{
>>> +    return (void *)phys_addr;
>>> +}
>>>
>>>   void __init early_iounmap(void __iomem *addr, unsigned long size)
>>>   {
>>>
>>
>> --
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>>
>
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Re: [Patch V6 12/16] mm: provide early_memremap_ro to establish  read-only mapping Juergen Gross <jgross@suse.com> - 2015-08-05 13:20 +0200

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