Replacing (n & (n-1)) in the context of power of 2 checks
with is_power_of_2
Signed-off-by: vignesh babu <vignesh.babu@wipro.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>
Get rid of the notifier list and call the kprobes code directly
if compiled in. This mirrors the changes that recently went
into powerpc, s390 and sparc64.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Tony Luck <tony.luck@intel.com>
IA64 is the origin of the quicklist implementation. So cut out the pieces
that are now in core code and modify the functions called.
Signed-off-by: Christoph Lameter <clameter@sgi.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Tony Luck <tony.luck@intel.com>
* git://git.kernel.org/pub/scm/linux/kernel/git/aegl/linux-2.6:
[IA64] wire up pselect, ppoll
[IA64] Add TIF_RESTORE_SIGMASK
[IA64] unwind did not work for processes born with CLONE_STOPPED
[IA64] Optional method to purge the TLB on SN systems
[IA64] SPIN_LOCK_UNLOCKED macro cleanup in arch/ia64
[IA64-SN2][KJ] mmtimer.c-kzalloc
[IA64] fix stack alignment for ia32 signal handlers
[IA64] - Altix: hotplug after intr redirect can crash system
[IA64] save and restore cpus_allowed in cpu_idle_wait
[IA64] Removal of percpu TR cleanup in kexec code
[IA64] Fix some section mismatch errors
Remove includes of <linux/smp_lock.h> where it is not used/needed.
Suggested by Al Viro.
Builds cleanly on x86_64, i386, alpha, ia64, powerpc, sparc,
sparc64, and arm (all 59 defconfigs).
Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This patch moves the die notifier handling to common code. Previous
various architectures had exactly the same code for it. Note that the new
code is compiled unconditionally, this should be understood as an appel to
the other architecture maintainer to implement support for it aswell (aka
sprinkling a notify_die or two in the proper place)
arm had a notifiy_die that did something totally different, I renamed it to
arm_notify_die as part of the patch and made it static to the file it's
declared and used at. avr32 used to pass slightly less information through
this interface and I brought it into line with the other architectures.
[akpm@linux-foundation.org: build fix]
[akpm@linux-foundation.org: fix vmalloc_sync_all bustage]
[bryan.wu@analog.com: fix vmalloc_sync_all in nommu]
Signed-off-by: Christoph Hellwig <hch@lst.de>
Cc: <linux-arch@vger.kernel.org>
Cc: Russell King <rmk@arm.linux.org.uk>
Signed-off-by: Bryan Wu <bryan.wu@analog.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This is to fix many section mismatches of code related to memory hotplug.
I checked compile with memory hotplug on/off on ia64 and x86-64 box.
Signed-off-by: Yasunori Goto <y-goto@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Handle MAP_FIXED in ia64 arch_get_unmapped_area and
hugetlb_get_unmapped_area(), just call prepare_hugepage_range in the later and
is_hugepage_only_range() in the former.
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Acked-by: William Irwin <bill.irwin@oracle.com>
Cc: "Luck, Tony" <tony.luck@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
If we add a new flag so that we can distinguish between the first page and the
tail pages then we can avoid to use page->private in the first page.
page->private == page for the first page, so there is no real information in
there.
Freeing up page->private makes the use of compound pages more transparent.
They become more usable like real pages. Right now we have to be careful f.e.
if we are going beyond PAGE_SIZE allocations in the slab on i386 because we
can then no longer use the private field. This is one of the issues that
cause us not to support debugging for page size slabs in SLAB.
Having page->private available for SLUB would allow more meta information in
the page struct. I can probably avoid the 16 bit ints that I have in there
right now.
Also if page->private is available then a compound page may be equipped with
buffer heads. This may free up the way for filesystems to support larger
blocks than page size.
We add PageTail as an alias of PageReclaim. Compound pages cannot currently
be reclaimed. Because of the alias one needs to check PageCompound first.
The RFC for the this approach was discussed at
http://marc.info/?t=117574302800001&r=1&w=2
[nacc@us.ibm.com: fix hugetlbfs]
Signed-off-by: Christoph Lameter <clameter@sgi.com>
Signed-off-by: Nishanth Aravamudan <nacc@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Example memory map (from HP sx1000 with VGA enabled):
0x00000 - 0x9FFFF supports only WB (cacheable) access
0xA0000 - 0xBFFFF supports only UC (uncacheable) access
0xC0000 - 0xFFFFF supports only WB (cacheable) access
pci_read_rom() indirectly uses ioremap(0xC0000) to read the shadow VGA option
ROM. ioremap() used to default to a 16MB or 64MB UC kernel identity mapping,
which would cause an MCA when reading 0xC0000 since only WB is supported there.
X uses reads the option ROM to initialize devices. A smaller test case is:
# echo 1 > /sys/bus/pci/devices/0000:aa:03.0/rom
# cp /sys/bus/pci/devices/0000:aa:03.0/rom x
To avoid this, we can use the same ioremap_page_range() strategy that most
architectures use for all ioremaps. These page table mappings come out of the
vmalloc area. On ia64, these are in region 5 (0xA... addresses) and typically
use 16KB or 64KB mappings instead of 16MB or 64MB mappings. The smaller
mappings give more flexibility to use the correct attributes.
Signed-off-by: Bjorn Helgaas <bjorn.helgaas@hp.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>
No functional change, just use the same names as i386.
Signed-off-by: Bjorn Helgaas <bjorn.helgaas@hp.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>
ia64 expects following vm layout:
== low memory
[register-stack grows up]
[memory-stack grows down]
== high memory
But the code assigns the base of the register stack at the
maximum stack size offset from the fixed address where the
stack *might* start. Stack randomization will result in the
memory stack starting at a lower address than this, and if the
user has set a low stack limit with "ulimit -s", then you can
end up with the register stack above the memory stack (or if
you were very unlucky right on top of it!).
Fix: Calculate the base address for the register stack starting
from the actual address of the memory stack.
Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>
We have seen bad_pte_print when testing crashdump on an SN machine in
recent 2.6.20 kernel. There are tons of bad pte print (pfn < max_low_pfn)
reports when the crash kernel boots up, all those reported bad pages
are inside initmem range; That is because if the crash kernel code and
data happens to be at the beginning of the 1st node. build_node_maps in
discontig.c will bypass reserved regions with filter_rsvd_memory. Since
min_low_pfn is calculated in build_node_map, so in this case, min_low_pfn
will be greater than kernel code and data.
Because pages inside initmem are freed and reused later, we saw
pfn_valid check fail on those pages.
I think this theoretically happen on a normal kernel. When I check
min_low_pfn and max_low_pfn calculation in contig.c and discontig.c.
I found more issues than this.
1. min_low_pfn and max_low_pfn calculation is inconsistent between
contig.c and discontig.c,
min_low_pfn is calculated as the first page number of boot memmap in
contig.c (Why? Though this may work at the most of the time, I don't
think it is the right logic). It is calculated as the lowest physical
memory page number bypass reserved regions in discontig.c.
max_low_pfn is calculated include reserved regions in contig.c. It is
calculated exclude reserved regions in discontig.c.
2. If kernel code and data region is happen to be at the begin or the
end of physical memory, when min_low_pfn and max_low_pfn calculation is
bypassed kernel code and data, pages in initmem will report bad.
3. initrd is also in reserved regions, if it is at the begin or at the
end of physical memory, kernel will refuse to reuse the memory. Because
the virt_addr_valid check in free_initrd_mem.
So it is better to fix and clean up those issues.
Calculate min_low_pfn and max_low_pfn in a consistent way.
Signed-off-by: Zou Nan hai <nanhai.zou@intel.com>
Acked-by: Jay Lan <jlan@sgi.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>
Make saved_max_pfn point to max_pfn of entire system.
Without this patch is so that vmcore is zero length on ia64. This is
because saved_max_pfn was wrongly being set to the max_pfn of the crash
kernel's address space, rather than the max_pfg on the physical memory of
the machine - the whole purpose of vmcore is to access physical memory that
is not part of the crash kernel's addresss space.
Signed-off-by: Simon Horman <horms@verge.net.au>
Signed-off-by: Zou Nan hai <nanhai.zou@intel.com>
Sort-Of-Acked-By: Jay Lan <jlan@sgi.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Tony Luck <tony.luck@intel.com>
Replace appropriate pairs of "kmem_cache_alloc()" + "memset(0)" with the
corresponding "kmem_cache_zalloc()" call.
Signed-off-by: Robert P. J. Day <rpjday@mindspring.com>
Cc: "Luck, Tony" <tony.luck@intel.com>
Cc: Andi Kleen <ak@muc.de>
Cc: Roland McGrath <roland@redhat.com>
Cc: James Bottomley <James.Bottomley@steeleye.com>
Cc: Greg KH <greg@kroah.com>
Acked-by: Joel Becker <Joel.Becker@oracle.com>
Cc: Steven Whitehouse <swhiteho@redhat.com>
Cc: Jan Kara <jack@ucw.cz>
Cc: Michael Halcrow <mhalcrow@us.ibm.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Stephen Smalley <sds@tycho.nsa.gov>
Cc: James Morris <jmorris@namei.org>
Cc: Chris Wright <chrisw@sous-sol.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
ZONE_DMA less operation for IA64 SGI platform
Disable ZONE_DMA for SGI SN2. All memory is addressable by all devices and we
do not need any special memory pool.
Signed-off-by: Christoph Lameter <clameter@sgi.com>
Cc: "Luck, Tony" <tony.luck@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Function is unnecessary now. We can use the summing features of the ZVCs to
get the values we need.
Signed-off-by: Christoph Lameter <clameter@sgi.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Instead of pinning per-cpu TLB into a DTR, use DTC. This will free up
one TLB entry for application, or even kernel if access pattern to
per-cpu data area has high temporal locality.
Since per-cpu is mapped at the top of region 7 address, we just need to
add special case in alt_dtlb_miss. The physical address of per-cpu data
is already conveniently stored in IA64_KR(PER_CPU_DATA). Latency for
alt_dtlb_miss is not affected as we can hide all the latency. It was
measured that alt_dtlb_miss handler has 23 cycles latency before and
after the patch.
The performance effect is massive for applications that put lots of tlb
pressure on CPU. Workload environment like database online transaction
processing or application uses tera-byte of memory would benefit the most.
Measurement with industry standard database benchmark shown an upward
of 1.6% gain. While smaller workloads like cpu, java also showing small
improvement.
Signed-off-by: Ken Chen <kenneth.w.chen@intel.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>
This patch fixes
- marking I-cache clean of pages DMAed to now only done for IA64
- broken multiple inclusion in include/asm-x86_64/swiotlb.h
- missing call to mark_clean in swiotlb_sync_sg()
- a (perhaps only theoretical) issue in swiotlb_dma_supported() when
io_tlb_end is exactly at the end of memory
Signed-off-by: Jan Beulich <jbeulich@novell.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Tony Luck <tony.luck@intel.com>
Eliminate arch specific memory_present call ia64 NUMA by utilizing
sparse_memory_present_with_active_regions.
Acked-by: Mel Gorman <mel@csn.ul.ie>
Signed-off-by: Bob Picco <bob.picco@hp.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Tony Luck <tony.luck@intel.com>
On the ia64 architecture only this patch upgrades show_mem() for sparse
memory to be the same as it was for discontig memory. It has been shown to
work on NUMA and flatmem architectures.
Signed-off-by: George Beshers <gbeshers@sgi.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Tony Luck <tony.luck@intel.com>
While pursuing and unrelated issue with 64Mb granules I noticed a problem
related to inconsistent use of add_active_range. There doesn't appear any
reason to me why FLATMEM versus DISCONTIG_MEM should register memory to
add_active_range with different code. So I've changed the code into a
common implementation.
The other subtle issue fixed by this patch was calling add_active_range in
count_node_pages before granule aligning is performed. We were lucky with
16MB granules but not so with 64MB granules. count_node_pages has reserved
regions filtered out and as a consequence linked kernel text and data
aren't covered by calls to count_node_pages. So linked kernel regions
wasn't reported to add_active_regions. This resulted in free_initmem
causing numerous bad_page reports. This won't occur with this patch
because now all known memory regions are reported by
register_active_ranges.
Acked-by: Mel Gorman <mel@csn.ul.ie>
Signed-off-by: Bob Picco <bob.picco@hp.com>
Acked-by: Simon Horman <horms@verge.net.au>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Tony Luck <tony.luck@intel.com>
Fix a typo in the saved_max_pfn description in contig.c
Signed-off-by: Simon Horman <horms@verge.net.au>
Signed-off-by: Tony Luck <tony.luck@intel.com>
Set saved_max_pfn when discontig memory is in use.
This sets up saved_max_pfn when disctontig memory is in use.
This mirrors the code for contig memory.
This patch does not entirely solve the problem of making vmcore work,
however it does appear to be neccessary. Please consider applying.
Signed-off-by: Simon Horman <horms@verge.net.au>
Signed-off-by: Tony Luck <tony.luck@intel.com>
Fix an oops experienced on the Cell architecture when init-time functions,
early_*(), are called at runtime. It alters the call paths to make sure
that the callers explicitly say whether the call is being made on behalf of
a hotplug even, or happening at boot-time.
It has been compile tested on ppc64, ia64, s390, i386 and x86_64.
Acked-by: Arnd Bergmann <arndb@de.ibm.com>
Signed-off-by: Dave Hansen <haveblue@us.ibm.com>
Cc: Yasunori Goto <y-goto@jp.fujitsu.com>
Acked-by: Andy Whitcroft <apw@shadowen.org>
Cc: Christoph Lameter <clameter@engr.sgi.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Acked-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This warning only shows up with CONFIG_VIRTUAL_MEM_MAP=y and
CONFIG_FLATMEM=y.
There is only one caller left for register_active_ranges() from the
contig.c code ... so it doesn't need to pick up the node number, the
node number is always zero.
Signed-off-by: Tony Luck <tony.luck@intel.com>
Actually, on reflection I think that there is a good case for
keeping the options separate. I am thinking particularly of people
who want a very small crashdump kernel and thus don't want to compile
in kexec.
The patch below should fix things up so that all valid combinations of
KEXEC, CRASH_DUMP and VMCORE compile cleanly - VMCORE depends on
CRASH_DUMP which is why I said valid combinations. In a nutshell
it just untangles unrelated code and switches around a few defines.
Please note that it creats a new file, arch/ia64/kernel/crash_dump.c
This is in keeping with the i386 implementation.
Signed-off-by: Simon Horman <horms@verge.net.au>
Signed-off-by: Tony Luck <tony.luck@intel.com>
SLAB_KERNEL is an alias of GFP_KERNEL.
Signed-off-by: Christoph Lameter <clameter@sgi.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Following up with the work on shared page table done by Dave McCracken. This
set of patch target shared page table for hugetlb memory only.
The shared page table is particular useful in the situation of large number of
independent processes sharing large shared memory segments. In the normal
page case, the amount of memory saved from process' page table is quite
significant. For hugetlb, the saving on page table memory is not the primary
objective (as hugetlb itself already cuts down page table overhead
significantly), instead, the purpose of using shared page table on hugetlb is
to allow faster TLB refill and smaller cache pollution upon TLB miss.
With PT sharing, pte entries are shared among hundreds of processes, the cache
consumption used by all the page table is smaller and in return, application
gets much higher cache hit ratio. One other effect is that cache hit ratio
with hardware page walker hitting on pte in cache will be higher and this
helps to reduce tlb miss latency. These two effects contribute to higher
application performance.
Signed-off-by: Ken Chen <kenneth.w.chen@intel.com>
Acked-by: Hugh Dickins <hugh@veritas.com>
Cc: Dave McCracken <dmccr@us.ibm.com>
Cc: William Lee Irwin III <wli@holomorphy.com>
Cc: "Luck, Tony" <tony.luck@intel.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: David Gibson <david@gibson.dropbear.id.au>
Cc: Adam Litke <agl@us.ibm.com>
Cc: Paul Mundt <lethal@linux-sh.org>
Cc: "David S. Miller" <davem@davemloft.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
(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 <hugh@veritas.com>
Cc: "Luck, Tony" <tony.luck@intel.com>
Cc: "David S. Miller" <davem@davemloft.net>
Acked-by: Adam Litke <agl@us.ibm.com>
Acked-by: David Gibson <david@gibson.dropbear.id.au>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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 <mel@csn.ul.ie>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
In cases where the acpi memory-add event does not containe the pxm (node)
infomation allow the driver to look up node info based on the address. The
acpi_get_node call returns -1 if it can't decode the pxm info, this causes
add_memory to panic. acpi_get_node would have to decode the resource from the
handle (a lenghty proposition). This seems to be the cleanist point to
interject the hook.
[kamezawa.hiroyu@jp.fujitsu.com: build fixes]
[y-goto@jp.fujitsu.com: build fixes]
Signed-off-by: Keith Mannthey <kmannth@us.ibm.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Andi Kleen <ak@muc.de>
Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Signed-off-by: Yasunori Goto <y-goto@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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 <ebiederm@xmission.com>
Signed-off-by: Sukadev Bhattiprolu <sukadev@us.ibm.com>
Cc: Dave Hansen <haveblue@us.ibm.com>
Cc: Serge Hallyn <serue@us.ibm.com>
Cc: Cedric Le Goater <clg@fr.ibm.com>
Cc: <lxc-devel@lists.sourceforge.net>
Acked-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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 <jbaron@redhat.com>
Cc: Russell King <rmk@arm.linux.org.uk>
Cc: "Luck, Tony" <tony.luck@intel.com>
Cc: Hugh Dickins <hugh@veritas.com>
Cc: Roman Zippel <zippel@linux-m68k.org>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Acked-by: Andi Kleen <ak@muc.de>
Acked-by: Alan Cox <alan@lxorguk.ukuu.org.uk>
Cc: Arjan van de Ven <arjan@linux.intel.com>
Acked-by: Paul Mundt <lethal@linux-sh.org>
Cc: Kazumoto Kojima <kkojima@rr.iij4u.or.jp>
Cc: Ian Molton <spyro@f2s.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* 'release' of git://git.kernel.org/pub/scm/linux/kernel/git/aegl/linux-2.6:
[IA64] minor reformatting to vmlinux.lds.S
[IA64] CMC/CPE: Reverse the order of fetching log and checking poll threshold
[IA64] PAL calls need physical mode, stacked
[IA64] ar.fpsr not set on MCA/INIT kernel entry
[IA64] printing support for MCA/INIT
[IA64] trim output of show_mem()
[IA64] show_mem() printk levels
[IA64] Make gp value point to Region 5 in mca handler
Revert "[IA64] Unwire set/get_robust_list"
[IA64] Implement futex primitives
[IA64-SGI] Do not request DMA memory for BTE
[IA64] Move perfmon tables from thread_struct to pfm_context
[IA64] Add interface so modules can discover whether multithreading is on.
[IA64] kprobes: fixup the pagefault exception caused by probehandlers
[IA64] kprobe opcode 16 bytes alignment on IA64
[IA64] esi-support
[IA64] Add "model name" to /proc/cpuinfo
Cut the number of lines of memory info output per node from five
to one line.
Signed-off-by: Jes Sorensen <jes@sgi.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>
Use the default sysrq printk level for printing show_mem() output both
for disconfig and contig versions. This is consistent with the printk
level used on other architectures (well ia32 at least).
Signed-off-by: Jes Sorensen <jes@sgi.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>
contig.c (FLATMEM) requires the same optimization as in discontig.c for show_mem
when VIRTUAL_MEM_MAP is in use. Otherwise FLATMEM has softlockup timeouts.
This was boot tested for memory configuration: SPARSEMEM,
DISCONTIG+VIRTUAL_MEM_MAP, FLATMEM, FLATMEM+VIRTUAL_MEM_MAP and
FLATMEM+VIRTUAL_MEM_MAP with largest memory gap less than LARGE_GAP by
using boot parameter "mem=".
This was boot tested and "echo m >/proc/sysrq-trigger" output evaluated for
: FLATMEM, FLATMEM+VIRTUAL_MEM_MAP, DISCONTIGMEM+VIRTUAL_MEM_MAP and
SPARSEMEM.
Signed-off-by: Bob Picco <bob.picco@hp.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>
Assure that vmem_map's high endpoint is MAX_ORDER aligned. Not doing so violates
the buddy allocator algorithm. Also anyone using mem=XXX on boot line and
not aligned to MAX_ORDER requires this patch in order to satisfy buddy
allocator. vmem_map always starts at pfn 0. The potentially large MAX_ORDER
on ia64 (due to hugetlbfs) requires that the end of vmem_map be aligned
to MAX_ORDER_NR_PAGES.
This was boot tested for: FLATMEM, FLATMEM+VIRTUAL_MEM_MAP,
DISCONTIGMEM+VIRTUAL_MEM_MAP and SPARSEMEM.
Signed-off-by: Bob Picco <bob.picco@hp.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>
Fix some sparse warnings on ia64. Large constants that should be long
instead of int. Use NULL instead of 0. Add some missing __iomem
casts. Replace a non-C99 structure assignment.
Signed-off-by: Keith Owens <kaos@sgi.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>
I found a bug in memory hot-add code for ia64.
IA64's code has copies of pgdat's array on each node to reduce memory
access over crossing node. This array is used by NODE_DATA() macro. When
new node is hot-added, this pgdat's array should be updated and copied on
new node too.
However, I used for_each_online_node() in scatter_node_data() to copy
it. This meant its array is not copied on new node.
Because initialization of structures for new node was halfway,
so online_node_map couldn't be set at this time.
To copy arrays on new node, I changed it to check value of pgdat_list[]
which is source array of copies. I tested this patch with my Memory Hotadd
emulation on Tiger4. This patch is for 2.6.17-git20.
Signed-off-by: Yasunori Goto <y-goto@jp.fujitsu.com>
Cc: "Luck, Tony" <tony.luck@intel.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This is a patch to allocate pgdat and per node data area for ia64. The size
for them can be calculated by compute_pernodesize().
Signed-off-by: Yasunori Goto <y-goto@jp.fujitsu.com>
Cc: "Luck, Tony" <tony.luck@intel.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This is to refresh node_data[] array for ia64. As I mentioned previous
patches, ia64 has copies of information of pgdat address array on each node as
per node data.
At v2 of node_add, this function used stop_machine_run() to update them. (I
wished that they were copied safety as much as possible.) But, in this patch,
this arrays are just copied simply, and set node_online_map bit after
completion of pgdat initialization.
So, kernel must touch NODE_DATA() macro after checking node_online_map().
(Current code has already done it.) This is more simple way for just
hot-add.....
Note : It will be problem when hot-remove will occur,
because, even if online_map bit is set, kernel may
touch NODE_DATA() due to race condition. :-(
Signed-off-by: Yasunori Goto <y-goto@jp.fujitsu.com>
Cc: "Luck, Tony" <tony.luck@intel.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
vignesh babu