> "Andrew" == Andrew Morton <[EMAIL PROTECTED]> writes:
Andrew> Jes Sorensen <[EMAIL PROTECTED]> wrote:
>> Convert /dev/mem read/write calls to use arch_translate_mem_ptr if
>> available. Needed on ia64 for pages converted fo uncached mappings
>> to avoid it being accessed in cached mode afte
Jes Sorensen <[EMAIL PROTECTED]> wrote:
>
> Convert /dev/mem read/write calls to use arch_translate_mem_ptr if
> available. Needed on ia64 for pages converted fo uncached mappings to
> avoid it being accessed in cached mode after the conversion which can
> lead to memory corruption. Introduces P
> "Jes" == Jes Sorensen <[EMAIL PROTECTED]> writes:
> "Andrew" == Andrew Morton <[EMAIL PROTECTED]> writes:
Andrew> This patch causes hiccups on my ia32e box.
Andrew> linux:/home/akpm# /usr/sbin/hwscan --isapnp zsh: 7528
Andrew> segmentation fault
Jes> Weird, I'll take a look.
-EPROGRAM
> "Andrew" == Andrew Morton <[EMAIL PROTECTED]> writes:
Andrew> [EMAIL PROTECTED] (Jes Sorensen) wrote:
>> This patch introduces ia64 specific read/write handlers for
>> /dev/mem access which is needed to avoid uncached pages to be
>> accessed through the cached kernel window which can lead t
[EMAIL PROTECTED] (Jes Sorensen) wrote:
>
> This patch introduces ia64 specific read/write handlers for /dev/mem
> access which is needed to avoid uncached pages to be accessed through
> the cached kernel window which can lead to random corruption.
This patch causes hiccups on my ia32e box.
lin
> "Christoph" == Christoph Hellwig <[EMAIL PROTECTED]> writes:
Christoph> Please remove the ifdef by letting every architecture
Christoph> implement a arch_translate_mem_ptr (and give it a saner
Christoph> name while you're at it).
Ok, I thought it was tidier the other way, but I am not biase
> + page = pfn_to_page(p >> PAGE_SHIFT);
> + /*
> + * On ia64 if a page has been mapped somewhere as
> + * uncached, then it must also be accessed uncached
> + * by the kernel or data corruption may occur
> + */
> +#ifdef A
> "Andrew" == Andrew Morton <[EMAIL PROTECTED]> writes:
Andrew> Jes Sorensen <[EMAIL PROTECTED]> wrote:
>> After applying the clue 2x4 to my head a couple of times, I came
>> up with this patch. Hopefully it will work a bit better ;-)
>>
Andrew> I know it's repetitious, but it's nice to mai
> However what happens if someone wants to share say some
> texture ram between the kernel and a video card and that has to be
> mapped uncached? Though up example here though.
also that's surely supposed to be controlled by some kernel driver,
which in turn can and should export it's own mmap in
> "Arjan" == Arjan van de Ven <[EMAIL PROTECTED]> writes:
Arjan> On Tue, 2005-02-22 at 17:30 -0500, Jes Sorensen wrote:
>> For userspace it's used by some of the MPI type apps in userland.
Arjan> you got to be kidding. Why are these MPI apps accessing memory
Arjan> that the kernel has mapped
On Tue, 2005-02-22 at 16:38 -0500, Jes Sorensen wrote:
> > "Dave" == Dave Hansen <[EMAIL PROTECTED]> writes:
>
> Dave> I was talking with Nigel Cunningham about doing something a
> Dave> little different from the classic page flag bits when the number
> Dave> of users is restricted and perform
Jes Sorensen <[EMAIL PROTECTED]> wrote:
>
> After applying the clue 2x4 to my head a couple of times, I came up
> with this patch. Hopefully it will work a bit better ;-)
>
I know it's repetitious, but it's nice to maintain a changelog entry along
with the patch. Especially when seventy people h
On Tue, 2005-02-22 at 17:30 -0500, Jes Sorensen wrote:
>
> For userspace it's used by some of the MPI type apps in userland.
you got to be kidding. Why are these MPI apps accessing memory that the
kernel has mapped cached (eg ram) via /dev/mem?
(eg my proposal is to make /dev/mem to be just dev
> "Andrew" == Andrew Morton <[EMAIL PROTECTED]> writes:
Andrew> Matthew Wilcox <[EMAIL PROTECTED]> wrote:
>>
>> On Tue, Feb 22, 2005 at 09:41:04AM -0500, Jes Sorensen wrote:
>> > >> + if (page->flags & PG_uncached)
>> >
>> > Andrew> dude. That ain't gonna work ;)
>> >
>> > Pardon my lack o
> "Arjan" == Arjan van de Ven <[EMAIL PROTECTED]> writes:
Arjan> On Tue, 2005-02-22 at 04:52 -0500, Jes Sorensen wrote:
>> Hi,
>>
>> This patch introduces ia64 specific read/write handlers for
>> /dev/mem access which is needed to avoid uncached pages to be
>> accessed through the cached kern
On Tue, 2005-02-22 at 04:52 -0500, Jes Sorensen wrote:
> Hi,
>
> This patch introduces ia64 specific read/write handlers for /dev/mem
> access which is needed to avoid uncached pages to be accessed through
> the cached kernel window which can lead to random corruption. It also
> introduces a new p
> "Dave" == Dave Hansen <[EMAIL PROTECTED]> writes:
Dave> I was talking with Nigel Cunningham about doing something a
Dave> little different from the classic page flag bits when the number
Dave> of users is restricted and performance isn't ultra-critical.
Dave> Would something like this work f
> "Andrew" == Andrew Morton <[EMAIL PROTECTED]> writes:
Andrew> Matthew Wilcox <[EMAIL PROTECTED]> wrote:
>>
>> On Tue, Feb 22, 2005 at 09:41:04AM -0500, Jes Sorensen wrote:
>> > >> + if (page->flags & PG_uncached)
>> >
>> > Andrew> dude. That ain't gonna work ;)
>> >
>> > Pardon my lack o
I was talking with Nigel Cunningham about doing something a little
different from the classic page flag bits when the number of users is
restricted and performance isn't ultra-critical. Would something like
this work for you, instead of using a real page->flags bit for
PG_cached?
http://marc.thea
Matthew Wilcox <[EMAIL PROTECTED]> wrote:
>
> On Tue, Feb 22, 2005 at 09:41:04AM -0500, Jes Sorensen wrote:
> > >> + if (page->flags & PG_uncached)
> >
> > Andrew> dude. That ain't gonna work ;)
> >
> > Pardon my lack of clue, but why not?
if (page->flags & (1< I think you're supp
>On Tue, Feb 22, 2005 at 09:41:04AM -0500, Jes Sorensen wrote:
>> >> + if (page->flags & PG_uncached)
>>
>> Andrew> dude. That ain't gonna work ;)
>>
>> Pardon my lack of clue, but why not?
>
>I think you're supposed to always use test_bit() to check page flags
You defined PG_uncached as "20" .
On Tue, Feb 22, 2005 at 09:41:04AM -0500, Jes Sorensen wrote:
> >> + if (page->flags & PG_uncached)
>
> Andrew> dude. That ain't gonna work ;)
>
> Pardon my lack of clue, but why not?
I think you're supposed to always use test_bit() to check page flags
--
"Next the statesmen will invent cheap
> "Andrew" == Andrew Morton <[EMAIL PROTECTED]> writes:
Andrew> [EMAIL PROTECTED] (Jes Sorensen) wrote:
>> Hi,
>>
>> This patch introduces ia64 specific read/write handlers for
>> /dev/mem access which is needed to avoid uncached pages to be
>> accessed through the cached kernel window which
Andrew Morton <[EMAIL PROTECTED]> writes:
>
> Is it possible to avoid consuming a page flag?
>
> If this is an ia64-only (or 64-bit-only) thing I guess we could use bit 32.
It's not. i386 essentially has the same problem. Other architectures
likely too. We definitely need a generic solution, espec
[EMAIL PROTECTED] (Jes Sorensen) wrote:
>
> Hi,
>
> This patch introduces ia64 specific read/write handlers for /dev/mem
> access which is needed to avoid uncached pages to be accessed through
> the cached kernel window which can lead to random corruption. It also
> introduces a new page-flag PG_u
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