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[PATCH] powerpc: fix for hugepage areas straddling 4GB boundary

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Commit 7d24f0b8a5 fixed bugs in the ppc64 SLB
miss handler with respect to hugepage handling, and in the process tweaked
the semantics of the hugepage address masks in mm_context_t.

Unfortunately, it left out a couple of necessary changes to go with that
change.  First, the in_hugepage_area() macro was not updated to match,
second prepare_hugepage_range() was not updated to correctly handle
hugepages regions which straddled the 4GB point.

The latter appears only to cause process-hangs when attempting to map such
a region, but the former can cause oopses if a get_user_pages() is
triggered at the wrong point.  This patch addresses both bugs.

Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This commit is contained in:
David Gibson 2005-11-23 13:37:45 -08:00 committed by Linus Torvalds
parent e9b15b54d3
commit 5e391dc9e3
2 changed files with 6 additions and 6 deletions
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6
arch/powerpc/mm/hugetlbpage.c
View file

@ -287,15 +287,15 @@ static int open_high_hpage_areas(struct mm_struct *mm, u16 newareas)
int prepare_hugepage_range(unsigned long addr, unsigned long len)
{
int err;
int err = 0;
if ( (addr+len) < addr )
return -EINVAL;
if ((addr + len) < 0x100000000UL)
if (addr < 0x100000000UL)
err = open_low_hpage_areas(current->mm,
LOW_ESID_MASK(addr, len));
else
if ((addr + len) >= 0x100000000UL)
err = open_high_hpage_areas(current->mm,
HTLB_AREA_MASK(addr, len));
if (err) {

6
include/asm-powerpc/page_64.h
View file

@ -135,9 +135,9 @@ extern unsigned int HPAGE_SHIFT;
#define in_hugepage_area(context, addr) \
(cpu_has_feature(CPU_FTR_16M_PAGE) && \
( ((1 << GET_HTLB_AREA(addr)) & (context).high_htlb_areas) || \
( ((addr) < 0x100000000L) && \
((1 << GET_ESID(addr)) & (context).low_htlb_areas) ) ) )
( ( (addr) >= 0x100000000UL) \
? ((1 << GET_HTLB_AREA(addr)) & (context).high_htlb_areas) \
: ((1 << GET_ESID(addr)) & (context).low_htlb_areas) ) )
#else /* !CONFIG_HUGETLB_PAGE */