kernel.git/arch/powerpc/mm, branch linux-2.6.19.y

[PATCH] hugetlb: prepare_hugepage_range check offset too

2006-11-14T17:09:27Z

(David:) If hugetlbfs_file_mmap() returns a failure to do_mmap_pgoff() - for example, because the given file offset is not hugepage aligned - then do_mmap_pgoff will go to the unmap_and_free_vma backout path. But at this stage the vma hasn't been marked as hugepage, and the backout path will call unmap_region() on it. That will eventually call down to the non-hugepage version of unmap_page_range(). On ppc64, at least, that will cause serious problems if there are any existing hugepage pagetable entries in the vicinity - for example if there are any other hugepage mappings under the same PUD. unmap_page_range() will trigger a bad_pud() on the hugepage pud entries. I suspect this will also cause bad problems on ia64, though I don't have a machine to test it on. (Hugh:) prepare_hugepage_range() should check file offset alignment when it checks virtual address and length, to stop MAP_FIXED with a bad huge offset from unmapping before it fails further down. PowerPC should apply the same prepare_hugepage_range alignment checks as ia64 and all the others do. Then none of the alignment checks in hugetlbfs_file_mmap are required (nor is the check for too small a mapping); but even so, move up setting of VM_HUGETLB and add a comment to warn of what David Gibson discovered - if hugetlbfs_file_mmap fails before setting it, do_mmap_pgoff's unmap_region when unwinding from error will go the non-huge way, which may cause bad behaviour on architectures (powerpc and ia64) which segregate their huge mappings into a separate region of the address space. Signed-off-by: Hugh Dickins Cc: "Luck, Tony" Cc: "David S. Miller" Acked-by: Adam Litke Acked-by: David Gibson Cc: Paul Mackerras Cc: Benjamin Herrenschmidt Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

[POWERPC] Make high hugepage areas preempt safe

2006-11-01T03:52:48Z

Checking source for other get_paca()->field preemption dangers found that open_high_hpage_areas does a structure copy into its paca while preemption is enabled: unsafe however gcc accomplishes it. Just remove that copy: it's done safely afterwards by on_each_cpu, as in open_low_hpage_areas. Signed-off-by: Hugh Dickins Acked-by: David Gibson Signed-off-by: Paul Mackerras

[PATCH] mm: use symbolic names instead of indices for zone initialisation

2006-10-11T18:14:14Z

Arch-independent zone-sizing is using indices instead of symbolic names to offset within an array related to zones (max_zone_pfns). The unintended impact is that ZONE_DMA and ZONE_NORMAL is initialised on powerpc instead of ZONE_DMA and ZONE_HIGHMEM when CONFIG_HIGHMEM is set. As a result, the the machine fails to boot but will boot with CONFIG_HIGHMEM turned off. The following patch properly initialises the max_zone_pfns[] array and uses symbolic names instead of indices in each architecture using arch-independent zone-sizing. Two users have successfully booted their powerpcs with it (one an ibook G4). It has also been boot tested on x86, x86_64, ppc64 and ia64. Please merge for 2.6.19-rc2. Credit to Benjamin Herrenschmidt for identifying the bug and rolling the first fix. Additional credit to Johannes Berg and Andreas Schwab for reporting the problem and testing on powerpc. Signed-off-by: Mel Gorman Cc: Benjamin Herrenschmidt Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

Merge branch 'master' of git://oak/home/sfr/kernels/iseries/work

2006-10-04T05:02:27Z

[POWERPC] implement BEGIN/END_FW_FTR_SECTION

2006-10-03T06:50:21Z

and use it an all the obvious places in assembler code. Signed-off-by: Stephen Rothwell

[PATCH] pidspace: is_init()

2006-09-29T16:18:12Z

This is an updated version of Eric Biederman's is_init() patch. (http://lkml.org/lkml/2006/2/6/280). It applies cleanly to 2.6.18-rc3 and replaces a few more instances of ->pid == 1 with is_init(). Further, is_init() checks pid and thus removes dependency on Eric's other patches for now. Eric's original description: There are a lot of places in the kernel where we test for init because we give it special properties. Most significantly init must not die. This results in code all over the kernel test ->pid == 1. Introduce is_init to capture this case. With multiple pid spaces for all of the cases affected we are looking for only the first process on the system, not some other process that has pid == 1. Signed-off-by: Eric W. Biederman Signed-off-by: Sukadev Bhattiprolu Cc: Dave Hansen Cc: Serge Hallyn Cc: Cedric Le Goater Cc: Acked-by: Paul Mackerras Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

[PATCH] make PROT_WRITE imply PROT_READ

2006-09-29T16:18:05Z

Make PROT_WRITE imply PROT_READ for a number of architectures which don't support write only in hardware. While looking at this, I noticed that some architectures which do not support write only mappings already take the exact same approach. For example, in arch/alpha/mm/fault.c: " if (cause < 0) { if (!(vma->vm_flags & VM_EXEC)) goto bad_area; } else if (!cause) { /* Allow reads even for write-only mappings */ if (!(vma->vm_flags & (VM_READ | VM_WRITE))) goto bad_area; } else { if (!(vma->vm_flags & VM_WRITE)) goto bad_area; } " Thus, this patch brings other architectures which do not support write only mappings in-line and consistent with the rest. I've verified the patch on ia64, x86_64 and x86. Additional discussion: Several architectures, including x86, can not support write-only mappings. The pte for x86 reserves a single bit for protection and its two states are read only or read/write. Thus, write only is not supported in h/w. Currently, if i 'mmap' a page write-only, the first read attempt on that page creates a page fault and will SEGV. That check is enforced in arch/blah/mm/fault.c. However, if i first write that page it will fault in and the pte will be set to read/write. Thus, any subsequent reads to the page will succeed. It is this inconsistency in behavior that this patch is attempting to address. Furthermore, if the page is swapped out, and then brought back the first read will also cause a SEGV. Thus, any arbitrary read on a page can potentially result in a SEGV. According to the SuSv3 spec, "if the application requests only PROT_WRITE, the implementation may also allow read access." Also as mentioned, some archtectures, such as alpha, shown above already take the approach that i am suggesting. The counter-argument to this raised by Arjan, is that the kernel is enforcing the write only mapping the best it can given the h/w limitations. This is true, however Alan Cox, and myself would argue that the inconsitency in behavior, that is applications can sometimes work/sometimes fails is highly undesireable. If you read through the thread, i think people, came to an agreement on the last patch i posted, as nobody has objected to it... Signed-off-by: Jason Baron Cc: Russell King Cc: "Luck, Tony" Cc: Hugh Dickins Cc: Roman Zippel Cc: Geert Uytterhoeven Cc: Paul Mackerras Cc: Benjamin Herrenschmidt Acked-by: Andi Kleen Acked-by: Alan Cox Cc: Arjan van de Ven Acked-by: Paul Mundt Cc: Kazumoto Kojima Cc: Ian Molton Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

[PATCH] Have Power use add_active_range() and free_area_init_nodes()

2006-09-27T15:26:11Z

Size zones and holes in an architecture independent manner for Power. [judith@osdl.org: build fix] Signed-off-by: Mel Gorman Cc: Dave Hansen Cc: Andy Whitcroft Cc: Andi Kleen Cc: Benjamin Herrenschmidt Cc: Paul Mackerras Cc: "Keith Mannthey" Cc: "Luck, Tony" Cc: KAMEZAWA Hiroyuki Cc: Yasunori Goto Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

[POWERPC] fix ioremap for a combined kernel

2006-09-25T03:36:31Z

Signed-off-by: Stephen Rothwell

Merge branch 'merge'

2006-08-25T04:56:07Z