From 01edcd891c3e9f4bb992ff2ceb69836bf76f8ddf Mon Sep 17 00:00:00 2001 From: Hugh Dickins Date: Wed, 23 Nov 2005 13:37:39 -0800 Subject: [PATCH] mm: powerpc ptlock comments Update comments (only) on page_table_lock and mmap_sem in arch/powerpc. Removed the comment on page_table_lock from hash_huge_page: since it's no longer taking page_table_lock itself, it's irrelevant whether others are; but how it is safe (even against huge file truncation?) I can't say. Signed-off-by: Hugh Dickins Cc: Paul Mackerras Cc: Benjamin Herrenschmidt Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- arch/powerpc/mm/hugetlbpage.c | 4 +--- 1 file changed, 1 insertion(+), 3 deletions(-) (limited to 'arch/powerpc/mm/hugetlbpage.c') diff --git a/arch/powerpc/mm/hugetlbpage.c b/arch/powerpc/mm/hugetlbpage.c index 426c269e552e..9250f14be8ef 100644 --- a/arch/powerpc/mm/hugetlbpage.c +++ b/arch/powerpc/mm/hugetlbpage.c @@ -754,9 +754,7 @@ repeat: } /* - * No need to use ldarx/stdcx here because all who - * might be updating the pte will hold the - * page_table_lock + * No need to use ldarx/stdcx here */ *ptep = __pte(new_pte & ~_PAGE_BUSY); -- cgit v1.2.3 From 5e391dc9e3fec68922137ae317bf680a74656c1b Mon Sep 17 00:00:00 2001 From: David Gibson Date: Wed, 23 Nov 2005 13:37:45 -0800 Subject: [PATCH] powerpc: fix for hugepage areas straddling 4GB boundary Commit 7d24f0b8a53261709938ffabe3e00f88f6498df9 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 Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- arch/powerpc/mm/hugetlbpage.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) (limited to 'arch/powerpc/mm/hugetlbpage.c') diff --git a/arch/powerpc/mm/hugetlbpage.c b/arch/powerpc/mm/hugetlbpage.c index 9250f14be8ef..f867bba893ca 100644 --- a/arch/powerpc/mm/hugetlbpage.c +++ b/arch/powerpc/mm/hugetlbpage.c @@ -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) { -- cgit v1.2.3 From 9a94c5793a7b44720f19ebb71b636bc9c31b44d8 Mon Sep 17 00:00:00 2001 From: David Gibson Date: Thu, 24 Nov 2005 13:34:56 +1100 Subject: [PATCH] powerpc: More hugepage boundary case fixes Blah. The patch [0] I recently sent fixing errors with in_hugepage_area() and prepare_hugepage_range() for powerpc itself has an off-by-one bug. Furthermore, the related functions touches_hugepage_*_range() and within_hugepage_*_range() are also buggy. Some of the bugs, like those addressed in [0] originated with commit 7d24f0b8a53261709938ffabe3e00f88f6498df9 where we tweaked the semantics of where hugepages are allowed. Other bugs have been there essentially forever, and are due to the undefined behaviour of '<<' with shift counts greater than the type width (LOW_ESID_MASK could return non-zero for high ranges with the right congruences). The good news is that I now have a testsuite which should pick up things like this if they creep in again. [0] "powerpc-fix-for-hugepage-areas-straddling-4gb-boundary" Signed-off-by: David Gibson Signed-off-by: Paul Mackerras --- arch/powerpc/mm/hugetlbpage.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'arch/powerpc/mm/hugetlbpage.c') diff --git a/arch/powerpc/mm/hugetlbpage.c b/arch/powerpc/mm/hugetlbpage.c index f867bba893ca..6bc9dbad7dea 100644 --- a/arch/powerpc/mm/hugetlbpage.c +++ b/arch/powerpc/mm/hugetlbpage.c @@ -295,7 +295,7 @@ int prepare_hugepage_range(unsigned long addr, unsigned long len) if (addr < 0x100000000UL) err = open_low_hpage_areas(current->mm, LOW_ESID_MASK(addr, len)); - if ((addr + len) >= 0x100000000UL) + if ((addr + len) > 0x100000000UL) err = open_high_hpage_areas(current->mm, HTLB_AREA_MASK(addr, len)); if (err) { -- cgit v1.2.3