Re: [RFC PATCH 1/2] memremap: add arch specific hook for MEMREMAP_WB mappings

On 23 February 2016 at 23:23, Robert Jarzmik wrote: > Dan Williams writes: > >> On Tue, Feb 23, 2016 at 4:26 AM, Ard Biesheuvel >> wrote: >>> On 23 February 2016 at 13:03, Ard Biesheuvel

Re: [RFC PATCH 1/2] memremap: add arch specific hook for MEMREMAP_WB mappings

On 23 February 2016 at 23:23, Robert Jarzmik wrote: > Dan Williams writes: > >> On Tue, Feb 23, 2016 at 4:26 AM, Ard Biesheuvel >> wrote: >>> On 23 February 2016 at 13:03, Ard Biesheuvel >>> wrote: On 23 February 2016 at 12:58, Russell King - ARM Linux wrote: > On Mon, Feb 22,

Re: [RFC PATCH 1/2] memremap: add arch specific hook for MEMREMAP_WB mappings

Dan Williams writes: > On Tue, Feb 23, 2016 at 4:26 AM, Ard Biesheuvel > wrote: >> On 23 February 2016 at 13:03, Ard Biesheuvel >> wrote: >>> On 23 February 2016 at 12:58, Russell King - ARM Linux >>>

Re: [RFC PATCH 1/2] memremap: add arch specific hook for MEMREMAP_WB mappings

Dan Williams writes: > On Tue, Feb 23, 2016 at 4:26 AM, Ard Biesheuvel > wrote: >> On 23 February 2016 at 13:03, Ard Biesheuvel >> wrote: >>> On 23 February 2016 at 12:58, Russell King - ARM Linux >>> wrote: On Mon, Feb 22, 2016 at 09:35:24PM +0100, Ard Biesheuvel wrote: >> OK, I see

Re: [RFC PATCH 1/2] memremap: add arch specific hook for MEMREMAP_WB mappings

On Tue, Feb 23, 2016 at 4:26 AM, Ard Biesheuvel wrote: > On 23 February 2016 at 13:03, Ard Biesheuvel > wrote: >> On 23 February 2016 at 12:58, Russell King - ARM Linux >> wrote: >>> On Mon, Feb 22, 2016 at

Re: [RFC PATCH 1/2] memremap: add arch specific hook for MEMREMAP_WB mappings

On Tue, Feb 23, 2016 at 4:26 AM, Ard Biesheuvel wrote: > On 23 February 2016 at 13:03, Ard Biesheuvel > wrote: >> On 23 February 2016 at 12:58, Russell King - ARM Linux >> wrote: >>> On Mon, Feb 22, 2016 at 09:35:24PM +0100, Ard Biesheuvel wrote: OK, thanks for the historical context.

Re: [RFC PATCH 1/2] memremap: add arch specific hook for MEMREMAP_WB mappings

On 23 February 2016 at 13:03, Ard Biesheuvel wrote: > On 23 February 2016 at 12:58, Russell King - ARM Linux > wrote: >> On Mon, Feb 22, 2016 at 09:35:24PM +0100, Ard Biesheuvel wrote: >>> OK, thanks for the historical context. >>> >>> So what

Re: [RFC PATCH 1/2] memremap: add arch specific hook for MEMREMAP_WB mappings

On 23 February 2016 at 13:03, Ard Biesheuvel wrote: > On 23 February 2016 at 12:58, Russell King - ARM Linux > wrote: >> On Mon, Feb 22, 2016 at 09:35:24PM +0100, Ard Biesheuvel wrote: >>> OK, thanks for the historical context. >>> >>> So what is your opinion on this series, i.e., to wire up

Re: [RFC PATCH 1/2] memremap: add arch specific hook for MEMREMAP_WB mappings

On 23 February 2016 at 12:58, Russell King - ARM Linux wrote: > On Mon, Feb 22, 2016 at 09:35:24PM +0100, Ard Biesheuvel wrote: >> OK, thanks for the historical context. >> >> So what is your opinion on this series, i.e., to wire up memremap() to >> remap arbitrary memory

Re: [RFC PATCH 1/2] memremap: add arch specific hook for MEMREMAP_WB mappings

On 23 February 2016 at 12:58, Russell King - ARM Linux wrote: > On Mon, Feb 22, 2016 at 09:35:24PM +0100, Ard Biesheuvel wrote: >> OK, thanks for the historical context. >> >> So what is your opinion on this series, i.e., to wire up memremap() to >> remap arbitrary memory regions into the vmalloc

Re: [RFC PATCH 1/2] memremap: add arch specific hook for MEMREMAP_WB mappings

On Mon, Feb 22, 2016 at 09:35:24PM +0100, Ard Biesheuvel wrote: > OK, thanks for the historical context. > > So what is your opinion on this series, i.e., to wire up memremap() to > remap arbitrary memory regions into the vmalloc area with MT_MEMORY_RW > attributes, and at the same time lift the

Re: [RFC PATCH 1/2] memremap: add arch specific hook for MEMREMAP_WB mappings

On Mon, Feb 22, 2016 at 09:35:24PM +0100, Ard Biesheuvel wrote: > OK, thanks for the historical context. > > So what is your opinion on this series, i.e., to wire up memremap() to > remap arbitrary memory regions into the vmalloc area with MT_MEMORY_RW > attributes, and at the same time lift the

Re: [RFC PATCH 1/2] memremap: add arch specific hook for MEMREMAP_WB mappings

On 22 February 2016 at 21:02, Russell King - ARM Linux wrote: > On Mon, Feb 22, 2016 at 08:17:11PM +0100, Ard Biesheuvel wrote: >> I am not exactly sure why ioremap_cache() does not use MT_MEMORY_RW >> attributes, but the ARM architecture simply does not allow mismatched

Re: [RFC PATCH 1/2] memremap: add arch specific hook for MEMREMAP_WB mappings

On 22 February 2016 at 21:02, Russell King - ARM Linux wrote: > On Mon, Feb 22, 2016 at 08:17:11PM +0100, Ard Biesheuvel wrote: >> I am not exactly sure why ioremap_cache() does not use MT_MEMORY_RW >> attributes, but the ARM architecture simply does not allow mismatched >> attributes, so we

Re: [RFC PATCH 1/2] memremap: add arch specific hook for MEMREMAP_WB mappings

On Mon, Feb 22, 2016 at 08:17:11PM +0100, Ard Biesheuvel wrote: > I am not exactly sure why ioremap_cache() does not use MT_MEMORY_RW > attributes, but the ARM architecture simply does not allow mismatched > attributes, so we cannot simply replace each instance of > ioremap_cache() with memremap()

Re: [RFC PATCH 1/2] memremap: add arch specific hook for MEMREMAP_WB mappings

On Mon, Feb 22, 2016 at 08:17:11PM +0100, Ard Biesheuvel wrote: > I am not exactly sure why ioremap_cache() does not use MT_MEMORY_RW > attributes, but the ARM architecture simply does not allow mismatched > attributes, so we cannot simply replace each instance of > ioremap_cache() with memremap()

Re: [RFC PATCH 1/2] memremap: add arch specific hook for MEMREMAP_WB mappings

On Mon, Feb 22, 2016 at 11:17 AM, Ard Biesheuvel wrote: > On 22 February 2016 at 20:05, Dan Williams wrote: >> On Mon, Feb 22, 2016 at 6:02 AM, Ard Biesheuvel >> wrote: >>> Currently, the memremap code serves

Re: [RFC PATCH 1/2] memremap: add arch specific hook for MEMREMAP_WB mappings

On Mon, Feb 22, 2016 at 11:17 AM, Ard Biesheuvel wrote: > On 22 February 2016 at 20:05, Dan Williams wrote: >> On Mon, Feb 22, 2016 at 6:02 AM, Ard Biesheuvel >> wrote: >>> Currently, the memremap code serves MEMREMAP_WB mappings directly from >>> the kernel direct mapping, unless the region is

Re: [RFC PATCH 1/2] memremap: add arch specific hook for MEMREMAP_WB mappings

On 22 February 2016 at 20:05, Dan Williams wrote: > On Mon, Feb 22, 2016 at 6:02 AM, Ard Biesheuvel > wrote: >> Currently, the memremap code serves MEMREMAP_WB mappings directly from >> the kernel direct mapping, unless the region is in high

Re: [RFC PATCH 1/2] memremap: add arch specific hook for MEMREMAP_WB mappings

On 22 February 2016 at 20:05, Dan Williams wrote: > On Mon, Feb 22, 2016 at 6:02 AM, Ard Biesheuvel > wrote: >> Currently, the memremap code serves MEMREMAP_WB mappings directly from >> the kernel direct mapping, unless the region is in high memory, in which >> case it falls back to using

Re: [RFC PATCH 1/2] memremap: add arch specific hook for MEMREMAP_WB mappings

On Mon, Feb 22, 2016 at 6:02 AM, Ard Biesheuvel wrote: > Currently, the memremap code serves MEMREMAP_WB mappings directly from > the kernel direct mapping, unless the region is in high memory, in which > case it falls back to using ioremap_cache(). However, the

Re: [RFC PATCH 1/2] memremap: add arch specific hook for MEMREMAP_WB mappings

On Mon, Feb 22, 2016 at 6:02 AM, Ard Biesheuvel wrote: > Currently, the memremap code serves MEMREMAP_WB mappings directly from > the kernel direct mapping, unless the region is in high memory, in which > case it falls back to using ioremap_cache(). However, the semantics of > ioremap_cache() are

[RFC PATCH 1/2] memremap: add arch specific hook for MEMREMAP_WB mappings

Currently, the memremap code serves MEMREMAP_WB mappings directly from the kernel direct mapping, unless the region is in high memory, in which case it falls back to using ioremap_cache(). However, the semantics of ioremap_cache() are not unambiguously defined, and on ARM, it will actually result

[RFC PATCH 1/2] memremap: add arch specific hook for MEMREMAP_WB mappings

Currently, the memremap code serves MEMREMAP_WB mappings directly from the kernel direct mapping, unless the region is in high memory, in which case it falls back to using ioremap_cache(). However, the semantics of ioremap_cache() are not unambiguously defined, and on ARM, it will actually result