On Fri, Jan 29, 2010 at 01:06:20PM -0500, Ralf Baechle wrote:
> On Fri, Jan 29, 2010 at 09:11:46AM -0800, David Daney wrote:
>
> > >So first question would be: Has anyone successfully loaded a 64
> > >bit mips kernel with 2.6.32 and a page size of 16k or 64k ? This
> > >would at least help me reducing the problem to sb1.
> >
> > Yes, I routinely run with both 64K and 16K page sizes on 2.6.32 and
> > 2.6.33-rc*. I have not seen any crashes that can not be easily
> > explained.
>
> I can reproduce it with today's 14b7baff3eb4b1b46a592630e6f85ded9264798a.
> 4K page size works ok, 16K without IPv6 works ok and 16K with IPv6 crashes.
> Note, I was testing with a non-16K capable userland so ok means userland is
> reached.
>
> Either way, that's good enought to look into things.
>
16k page size works for me with the patch below. Not that I have any idea why;
this was just a blind test.
It seems to me that the notes in arch/mips/include/asm/pgtable-64.h regarding
available virtual memory per page size may contradict with the definition
of VMALLOC_END. VMALLOC_END-VMALLOC_START increases as the page size increases,
but the comments indicate that a system with 16k pages should have _less_
virtual memory available than a system with 4k pages because it only uses
a 2 level page table.
Guenter
---------------
git diff arch/mips/include/asm/pgtable-64.h
diff --git a/arch/mips/include/asm/pgtable-64.h b/arch/mips/include/asm/pgtable-64.h
index 9cd5089..bd61030 100644
--- a/arch/mips/include/asm/pgtable-64.h
+++ b/arch/mips/include/asm/pgtable-64.h
@@ -110,7 +110,7 @@
#define VMALLOC_START MAP_BASE
#define VMALLOC_END \
(VMALLOC_START + \
- PTRS_PER_PGD * PTRS_PER_PMD * PTRS_PER_PTE * PAGE_SIZE - (1UL << 32))
+ (PTRS_PER_PGD * PTRS_PER_PMD * PTRS_PER_PTE * PAGE_SIZE / 16) - (1UL << 32))
#if defined(CONFIG_MODULES) && defined(KBUILD_64BIT_SYM32) && \
VMALLOC_START != CKSSEG
/* Load modules into 32bit-compatible segment. */
