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* NOMMU: Don't pass NULL pointers to fput() in do_mmap_pgoff()David Howells2009-10-31
| | | | | | | | | | | | | | | | | | | | | Don't pass NULL pointers to fput() in the error handling paths of the NOMMU do_mmap_pgoff() as it can't handle it. The following can be used as a test program: int main() { static long long a[1024 * 1024 * 20] = { 0 }; return a;} Without the patch, the code oopses in atomic_long_dec_and_test() as called by fput() after the kernel complains that it can't allocate that big a chunk of memory. With the patch, the kernel just complains about the allocation size and then the program segfaults during execve() as execve() can't complete the allocation of all the new ELF program segments. Reported-by: Robin Getz <rgetz@blackfin.uclinux.org> Signed-off-by: David Howells <dhowells@redhat.com> Acked-by: Robin Getz <rgetz@blackfin.uclinux.org> Cc: stable@kernel.org Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* const: mark struct vm_struct_operationsAlexey Dobriyan2009-09-27
| | | | | | | | | | | * mark struct vm_area_struct::vm_ops as const * mark vm_ops in AGP code But leave TTM code alone, something is fishy there with global vm_ops being used. Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* NOMMU: Ignore mmap() address param as it is a hintDavid Howells2009-09-24
| | | | | | | | Ignore the address parameter given to NOMMU mmap() as it is a hint, rather than giving an error if it's non-zero. MAP_FIXED still gets an error. Signed-off-by: David Howells <dhowells@redhat.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* NOMMU: Fix MAP_PRIVATE mmap() of objects where the data can be mapped directlyDavid Howells2009-09-24
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Fix MAP_PRIVATE mmap() of files and devices where the data in the backing store might be mapped directly. Use the BDI_CAP_MAP_DIRECT capability flag to govern whether or not we should be trying to map a file directly. This can be used to determine whether or not a region has been filled in at the point where we call do_mmap_shared() or do_mmap_private(). The BDI_CAP_MAP_DIRECT capability flag is cleared by validate_mmap_request() if there's any reason we can't use it. It's also cleared in do_mmap_pgoff() if f_op->get_unmapped_area() fails. Without this fix, attempting to run a program from a RomFS image on a non-mappable MTD partition results in a BUG as the kernel attempts XIP, and this can be caught in gdb: Program received signal SIGABRT, Aborted. 0xc005dce8 in add_nommu_region (region=<value optimized out>) at mm/nommu.c:547 (gdb) bt #0 0xc005dce8 in add_nommu_region (region=<value optimized out>) at mm/nommu.c:547 #1 0xc005f168 in do_mmap_pgoff (file=0xc31a6620, addr=<value optimized out>, len=3808, prot=3, flags=6146, pgoff=0) at mm/nommu.c:1373 #2 0xc00a96b8 in elf_fdpic_map_file (params=0xc33fbbec, file=0xc31a6620, mm=0xc31bef60, what=0xc0213144 "executable") at mm.h:1145 #3 0xc00aa8b4 in load_elf_fdpic_binary (bprm=0xc316cb00, regs=<value optimized out>) at fs/binfmt_elf_fdpic.c:343 #4 0xc006b588 in search_binary_handler (bprm=0x6, regs=0xc33fbce0) at fs/exec.c:1234 #5 0xc006c648 in do_execve (filename=<value optimized out>, argv=0xc3ad14cc, envp=0xc3ad1460, regs=0xc33fbce0) at fs/exec.c:1356 #6 0xc0008cf0 in sys_execve (name=<value optimized out>, argv=0xc3ad14cc, envp=0xc3ad1460) at arch/frv/kernel/process.c:263 #7 0xc00075dc in __syscall_call () at arch/frv/kernel/entry.S:897 Note that this fix does the following commit differently: commit a190887b58c32d19c2eee007c5eb8faa970a69ba Author: David Howells <dhowells@redhat.com> Date: Sat Sep 5 11:17:07 2009 -0700 nommu: fix error handling in do_mmap_pgoff() Reported-by: Graff Yang <graff.yang@gmail.com> Signed-off-by: David Howells <dhowells@redhat.com> Acked-by: Pekka Enberg <penberg@cs.helsinki.fi> Cc: Paul Mundt <lethal@linux-sh.org> Cc: Mel Gorman <mel@csn.ul.ie> Cc: Greg Ungerer <gerg@snapgear.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* truncate: new helpersnpiggin@suse.de2009-09-24
| | | | | | | | | | Introduce new truncate helpers truncate_pagecache and inode_newsize_ok. vmtruncate is also consolidated from mm/memory.c and mm/nommu.c and into mm/truncate.c. Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Nick Piggin <npiggin@suse.de> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* nommu: fix two build breakagesHugh Dickins2009-09-23
| | | | | | | | | | | | | | | | | | | | | | | My 58fa879e1e640a1856f736b418984ebeccee1c95 "mm: FOLL flags for GUP flags" broke CONFIG_NOMMU build by forgetting to update nommu.c foll_flags type: mm/nommu.c:171: error: conflicting types for `__get_user_pages' mm/internal.h:254: error: previous declaration of `__get_user_pages' was here make[1]: *** [mm/nommu.o] Error 1 My 03f6462a3ae78f36eb1f0ee8b4d5ae2f7859c1d5 "mm: move highest_memmap_pfn" broke CONFIG_NOMMU build by forgetting to add a nommu.c highest_memmap_pfn: mm/built-in.o: In function `memmap_init_zone': (.meminit.text+0x326): undefined reference to `highest_memmap_pfn' mm/built-in.o: In function `memmap_init_zone': (.meminit.text+0x32d): undefined reference to `highest_memmap_pfn' Fix both breakages, and give myself 30 lashes (ouch!) Reported-by: Michal Simek <michal.simek@petalogix.com> Signed-off-by: Hugh Dickins <hugh.dickins@tiscali.co.uk> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* nommu: add support for Memory Protection Units (MPU)Bernd Schmidt2009-09-22
| | | | | | | | | | | | | | | | | | | | | Some architectures (like the Blackfin arch) implement some of the "simpler" features that one would expect out of a MMU such as memory protection. In our case, we actually get read/write/exec protection down to the page boundary so processes can't stomp on each other let alone the kernel. There is a performance decrease (which depends greatly on the workload) however as the hardware/software interaction was not optimized at design time. Signed-off-by: Bernd Schmidt <bernds_cb1@t-online.de> Signed-off-by: Bryan Wu <cooloney@kernel.org> Signed-off-by: Mike Frysinger <vapier@gentoo.org> Acked-by: David Howells <dhowells@redhat.com> Acked-by: Greg Ungerer <gerg@snapgear.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm: FOLL flags for GUP flagsHugh Dickins2009-09-22
| | | | | | | | | | | | | | | | | | | | | | __get_user_pages() has been taking its own GUP flags, then processing them into FOLL flags for follow_page(). Though oddly named, the FOLL flags are more widely used, so pass them to __get_user_pages() now. Sorry, VM flags, VM_FAULT flags and FAULT_FLAGs are still distinct. (The patch to __get_user_pages() looks peculiar, with both gup_flags and foll_flags: the gup_flags remain constant; but as before there's an exceptional case, out of scope of the patch, in which foll_flags per page have FOLL_WRITE masked off.) Signed-off-by: Hugh Dickins <hugh.dickins@tiscali.co.uk> Cc: Rik van Riel <riel@redhat.com> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: Nick Piggin <npiggin@suse.de> Cc: Mel Gorman <mel@csn.ul.ie> Cc: Minchan Kim <minchan.kim@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm: remove unused GUP flagsHugh Dickins2009-09-22
| | | | | | | | | | | | | | | | GUP_FLAGS_IGNORE_VMA_PERMISSIONS and GUP_FLAGS_IGNORE_SIGKILL were flags added solely to prevent __get_user_pages() from doing some of what it usually does, in the munlock case: we can now remove them. Signed-off-by: Hugh Dickins <hugh.dickins@tiscali.co.uk> Acked-by: Rik van Riel <riel@redhat.com> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: Nick Piggin <npiggin@suse.de> Cc: Mel Gorman <mel@csn.ul.ie> Cc: Minchan Kim <minchan.kim@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm: includecheck fix for mm/nommu.cJaswinder Singh Rajput2009-09-22
| | | | | | | | | | | | Fix the following 'make includecheck' warning: mm/nommu.c: internal.h is included more than once. Signed-off-by: Jaswinder Singh Rajput <jaswinderrajput@gmail.com> Cc: David Howells <dhowells@redhat.com> Acked-by: Greg Ungerer <gerg@snapgear.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* nommu: fix error handling in do_mmap_pgoff()David Howells2009-09-05
| | | | | | | | | | | | | | | | | | | | | Fix the error handling in do_mmap_pgoff(). If do_mmap_shared_file() or do_mmap_private() fail, we jump to the error_put_region label at which point we cann __put_nommu_region() on the region - but we haven't yet added the region to the tree, and so __put_nommu_region() may BUG because the region tree is empty or it may corrupt the region tree. To get around this, we can afford to add the region to the region tree before calling do_mmap_shared_file() or do_mmap_private() as we keep nommu_region_sem write-locked, so no-one can race with us by seeing a transient region. Signed-off-by: David Howells <dhowells@redhat.com> Acked-by: Pekka Enberg <penberg@cs.helsinki.fi> Acked-by: Paul Mundt <lethal@linux-sh.org> Cc: Mel Gorman <mel@csn.ul.ie> Acked-by: Greg Ungerer <gerg@snapgear.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* nommu: check fd read permission in validate_mmap_request()Graff Yang2009-08-18
| | | | | | | | | | | | | According to the POSIX (1003.1-2008), the file descriptor shall have been opened with read permission, regardless of the protection options specified to mmap(). The ltp test cases mmap06/07 need this. Signed-off-by: Graff Yang <graff.yang@gmail.com> Acked-by: Paul Mundt <lethal@linux-sh.org> Signed-off-by: David Howells <dhowells@redhat.com> Acked-by: Greg Ungerer <gerg@snapgear.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* Security/SELinux: seperate lsm specific mmap_min_addrEric Paris2009-08-17
| | | | | | | | | | | | | | | | | | | Currently SELinux enforcement of controls on the ability to map low memory is determined by the mmap_min_addr tunable. This patch causes SELinux to ignore the tunable and instead use a seperate Kconfig option specific to how much space the LSM should protect. The tunable will now only control the need for CAP_SYS_RAWIO and SELinux permissions will always protect the amount of low memory designated by CONFIG_LSM_MMAP_MIN_ADDR. This allows users who need to disable the mmap_min_addr controls (usual reason being they run WINE as a non-root user) to do so and still have SELinux controls preventing confined domains (like a web server) from being able to map some area of low memory. Signed-off-by: Eric Paris <eparis@redhat.com> Signed-off-by: James Morris <jmorris@namei.org>
* Merge git://git.kernel.org/pub/scm/linux/kernel/git/lethal/sh-2.6Linus Torvalds2009-07-01
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | * git://git.kernel.org/pub/scm/linux/kernel/git/lethal/sh-2.6: sh: LCDC dcache flush for deferred io sh: Fix compiler error and include the definition of IS_ERR_VALUE sh: re-add LCDC fbdev support to the Migo-R defconfig sh: fix se7724 ceu names sh: ms7724se: Enable sh_eth in defconfig. arch/sh/boards/mach-se/7206/io.c: Remove unnecessary semicolons sh: ms7724se: Add sh_eth support nommu: provide follow_pfn(). sh: Kill off unused DEBUG_BOOTMEM symbol. perf_counter tools: add cpu_relax()/rmb() definitions for sh. sh64: Hook up page fault events for software perf counters. sh: Hook up page fault events for software perf counters. sh: make set_perf_counter_pending() static inline. clocksource: sh_tmu: Make undefined TCOR behaviour less undefined.
| * nommu: provide follow_pfn().Paul Mundt2009-06-25
| | | | | | | | | | | | | | | | | | | | | | | | | | | | With the introduction of follow_pfn() as an exported symbol, modules have begun making use of it. Unfortunately this was not reflected on nommu at the time, so the in-tree users have subsequently all blown up with link errors there. This provides a simple follow_pfn() that just returns addr >> PAGE_SHIFT, which will do the right thing on nommu. There is no need to do range checking within the vma, as the find_vma() case will already take care of this. Signed-off-by: Paul Mundt <lethal@linux-sh.org>
* | clarify get_user_pages() prototypePeter Zijlstra2009-06-25
|/ | | | | | | | | Currently the 4th parameter of get_user_pages() is called len, but its in pages, not bytes. Rename the thing to nr_pages to avoid future confusion. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* nommu: Provide mmap_min_addr definition.Paul Mundt2009-06-09
| | | | | | | | | | | | | | | With the "security: use mmap_min_addr indepedently of security models" change, mmap_min_addr is used in common areas, which susbsequently blows up the nommu build. This stubs in the definition in the nommu case as well. Signed-off-by: Paul Mundt <lethal@linux-sh.org> -- mm/nommu.c | 3 +++ 1 file changed, 3 insertions(+) Signed-off-by: James Morris <jmorris@namei.org>
* NOMMU: Don't check vm_region::vm_start is page aligned in add_nommu_region()David Howells2009-05-07
| | | | | | | | | | Don't check vm_region::vm_start is page aligned in add_nommu_region() because the region may reflect some non-page-aligned mapped file, such as could be obtained from RomFS XIP. Signed-off-by: David Howells <dhowells@redhat.com> Acked-by: Greg Ungerer <gerg@uclinux.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* nommu: make the initial mmap allocation excess behaviour Kconfig configurableDavid Howells2009-05-06
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | NOMMU mmap() has an option controlled by a sysctl variable that determines whether the allocations made by do_mmap_private() should have the excess space trimmed off and returned to the allocator. Make the initial setting of this variable a Kconfig configuration option. The reason there can be excess space is that the allocator only allocates in power-of-2 size chunks, but mmap()'s can be made in sizes that aren't a power of 2. There are two alternatives: (1) Keep the excess as dead space. The dead space then remains unused for the lifetime of the mapping. Mappings of shared objects such as libc, ld.so or busybox's text segment may retain their dead space forever. (2) Return the excess to the allocator. This means that the dead space is limited to less than a page per mapping, but it means that for a transient process, there's more chance of fragmentation as the excess space may be reused fairly quickly. During the boot process, a lot of transient processes are created, and this can cause a lot of fragmentation as the pagecache and various slabs grow greatly during this time. By turning off the trimming of excess space during boot and disabling batching of frees, Coldfire can manage to boot. A better way of doing things might be to have /sbin/init turn this option off. By that point libc, ld.so and init - which are all long-duration processes - have all been loaded and trimmed. Reported-by: Lanttor Guo <lanttor.guo@freescale.com> Signed-off-by: David Howells <dhowells@redhat.com> Tested-by: Lanttor Guo <lanttor.guo@freescale.com> Cc: Greg Ungerer <gerg@snapgear.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm: fix Committed_AS underflow on large NR_CPUS environmentKOSAKI Motohiro2009-05-02
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The Committed_AS field can underflow in certain situations: > # while true; do cat /proc/meminfo | grep _AS; sleep 1; done | uniq -c > 1 Committed_AS: 18446744073709323392 kB > 11 Committed_AS: 18446744073709455488 kB > 6 Committed_AS: 35136 kB > 5 Committed_AS: 18446744073709454400 kB > 7 Committed_AS: 35904 kB > 3 Committed_AS: 18446744073709453248 kB > 2 Committed_AS: 34752 kB > 9 Committed_AS: 18446744073709453248 kB > 8 Committed_AS: 34752 kB > 3 Committed_AS: 18446744073709320960 kB > 7 Committed_AS: 18446744073709454080 kB > 3 Committed_AS: 18446744073709320960 kB > 5 Committed_AS: 18446744073709454080 kB > 6 Committed_AS: 18446744073709320960 kB Because NR_CPUS can be greater than 1000 and meminfo_proc_show() does not check for underflow. But NR_CPUS proportional isn't good calculation. In general, possibility of lock contention is proportional to the number of online cpus, not theorical maximum cpus (NR_CPUS). The current kernel has generic percpu-counter stuff. using it is right way. it makes code simplify and percpu_counter_read_positive() don't make underflow issue. Reported-by: Dave Hansen <dave@linux.vnet.ibm.com> Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: Eric B Munson <ebmunson@us.ibm.com> Cc: Mel Gorman <mel@csn.ul.ie> Cc: Christoph Lameter <cl@linux-foundation.org> Cc: <stable@kernel.org> [All kernel versions] Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* nommu: fix a number of issues with the per-MM VMA patchDavid Howells2009-04-02
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Fix a number of issues with the per-MM VMA patch: (1) Make mmap_pages_allocated an atomic_long_t, just in case this is used on a NOMMU system with more than 2G pages. Makes no difference on a 32-bit system. (2) Report vma->vm_pgoff * PAGE_SIZE as a 64-bit value, not a 32-bit value, lest it overflow. (3) Move the allocation of the vm_area_struct slab back for fork.c. (4) Use KMEM_CACHE() for both vm_area_struct and vm_region slabs. (5) Use BUG_ON() rather than if () BUG(). (6) Make the default validate_nommu_regions() a static inline rather than a #define. (7) Make free_page_series()'s objection to pages with a refcount != 1 more informative. (8) Adjust the __put_nommu_region() banner comment to indicate that the semaphore must be held for writing. (9) Limit the number of warnings about munmaps of non-mmapped regions. Reported-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: David Howells <dhowells@redhat.com> Cc: Greg Ungerer <gerg@snapgear.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* uclinux: add process name to allocation error messageGreg Ungerer2009-01-27
| | | | | | | | | This patch adds the name of the process to the bad allocation error message on non-MMU systems. Changed suggested by jsujjavanich@syntech-fuelmaster.com Signed-off-by: Greg Ungerer <gerg@uclinux.org>
* nommu: Stub in vm_map_ram()/vm_unmap_ram()/vm_unmap_aliases().Paul Mundt2009-01-21
| | | | | | | | Presently we do not support these interfaces, so make them BUG() wrappers as per the rest of the vmap interface on nommu. Fixes up the modular xfs build. Signed-off-by: Paul Mundt <lethal@linux-sh.org>
* [CVE-2009-0029] System call wrappers part 13Heiko Carstens2009-01-14
| | | | Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
* [CVE-2009-0029] Convert all system calls to return a longHeiko Carstens2009-01-14
| | | | | | | | | Convert all system calls to return a long. This should be a NOP since all converted types should have the same size anyway. With the exception of sys_exit_group which returned void. But that doesn't matter since the system call doesn't return. Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
* NOMMU: Teach kobjsize() about VMA regions.Paul Mundt2009-01-08
| | | | | | | | | | | | | | Now that we no longer use compound pages for all large allocations, kobjsize() actively breaks things like binfmt_flat by always handing back PAGE_SIZE for mmap'ed regions. Fix this up by looking up the VMA region for non-compounds. Ideally binfmt_flat wants to get rid of kobjsize() completely, but this is an incremental step. Signed-off-by: Paul Mundt <lethal@linux-sh.org> Signed-off-by: David Howells <dhowells@redhat.com> Tested-by: Mike Frysinger <vapier.adi@gmail.com>
* NOMMU: Make mmap allocation page trimming behaviour configurable.Paul Mundt2009-01-08
| | | | | | | | | | | | | | | | | | NOMMU mmap allocates a piece of memory for an mmap that's rounded up in size to the nearest power-of-2 number of pages. Currently it then discards the excess pages back to the page allocator, making that memory available for use by other things. This can, however, cause greater amount of fragmentation. To counter this, a sysctl is added in order to fine-tune the trimming behaviour. The default behaviour remains to trim pages aggressively, while this can either be disabled completely or set to a higher page-granular watermark in order to have finer-grained control. vm region vm_top bits taken from an earlier patch by David Howells. Signed-off-by: Paul Mundt <lethal@linux-sh.org> Signed-off-by: David Howells <dhowells@redhat.com> Tested-by: Mike Frysinger <vapier.adi@gmail.com>
* NOMMU: Make VMAs per MM as for MMU-mode linuxDavid Howells2009-01-08
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Make VMAs per mm_struct as for MMU-mode linux. This solves two problems: (1) In SYSV SHM where nattch for a segment does not reflect the number of shmat's (and forks) done. (2) In mmap() where the VMA's vm_mm is set to point to the parent mm by an exec'ing process when VM_EXECUTABLE is specified, regardless of the fact that a VMA might be shared and already have its vm_mm assigned to another process or a dead process. A new struct (vm_region) is introduced to track a mapped region and to remember the circumstances under which it may be shared and the vm_list_struct structure is discarded as it's no longer required. This patch makes the following additional changes: (1) Regions are now allocated with alloc_pages() rather than kmalloc() and with no recourse to __GFP_COMP, so the pages are not composite. Instead, each page has a reference on it held by the region. Anything else that is interested in such a page will have to get a reference on it to retain it. When the pages are released due to unmapping, each page is passed to put_page() and will be freed when the page usage count reaches zero. (2) Excess pages are trimmed after an allocation as the allocation must be made as a power-of-2 quantity of pages. (3) VMAs are added to the parent MM's R/B tree and mmap lists. As an MM may end up with overlapping VMAs within the tree, the VMA struct address is appended to the sort key. (4) Non-anonymous VMAs are now added to the backing inode's prio list. (5) Holes may be punched in anonymous VMAs with munmap(), releasing parts of the backing region. The VMA and region structs will be split if necessary. (6) sys_shmdt() only releases one attachment to a SYSV IPC shared memory segment instead of all the attachments at that addresss. Multiple shmat()'s return the same address under NOMMU-mode instead of different virtual addresses as under MMU-mode. (7) Core dumping for ELF-FDPIC requires fewer exceptions for NOMMU-mode. (8) /proc/maps is now the global list of mapped regions, and may list bits that aren't actually mapped anywhere. (9) /proc/meminfo gains a line (tagged "MmapCopy") that indicates the amount of RAM currently allocated by mmap to hold mappable regions that can't be mapped directly. These are copies of the backing device or file if not anonymous. These changes make NOMMU mode more similar to MMU mode. The downside is that NOMMU mode requires some extra memory to track things over NOMMU without this patch (VMAs are no longer shared, and there are now region structs). Signed-off-by: David Howells <dhowells@redhat.com> Tested-by: Mike Frysinger <vapier.adi@gmail.com> Acked-by: Paul Mundt <lethal@linux-sh.org>
* NOMMU: Delete askedalloc and realalloc variablesDavid Howells2009-01-08
| | | | | | | | | Delete the askedalloc and realalloc variables as nothing actually uses the value calculated. Signed-off-by: David Howells <dhowells@redhat.com> Tested-by: Mike Frysinger <vapier.adi@gmail.com> Acked-by: Paul Mundt <lethal@linux-sh.org>
* inode->i_op is never NULLAl Viro2009-01-05
| | | | | | | | | | We used to have rather schizophrenic set of checks for NULL ->i_op even though it had been eliminated years ago. You'd need to go out of your way to set it to NULL explicitly _and_ a bunch of code would die on such inodes anyway. After killing two remaining places that still did that bogosity, all that crap can go away. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* nfsd: fix vm overcommit crashAlan Cox2008-10-30
| | | | | | | | | | | | | | | | | | | | | | | | Junjiro R. Okajima reported a problem where knfsd crashes if you are using it to export shmemfs objects and run strict overcommit. In this situation the current->mm based modifier to the overcommit goes through a NULL pointer. We could simply check for NULL and skip the modifier but we've caught other real bugs in the past from mm being NULL here - cases where we did need a valid mm set up (eg the exec bug about a year ago). To preserve the checks and get the logic we want shuffle the checking around and add a new helper to the vm_ security wrappers Also fix a current->mm reference in nommu that should use the passed mm [akpm@linux-foundation.org: coding-style fixes] [akpm@linux-foundation.org: fix build] Reported-by: Junjiro R. Okajima <hooanon05@yahoo.co.jp> Acked-by: James Morris <jmorris@namei.org> Signed-off-by: Alan Cox <alan@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mlock: mlocked pages are unevictableNick Piggin2008-10-20
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Make sure that mlocked pages also live on the unevictable LRU, so kswapd will not scan them over and over again. This is achieved through various strategies: 1) add yet another page flag--PG_mlocked--to indicate that the page is locked for efficient testing in vmscan and, optionally, fault path. This allows early culling of unevictable pages, preventing them from getting to page_referenced()/try_to_unmap(). Also allows separate accounting of mlock'd pages, as Nick's original patch did. Note: Nick's original mlock patch used a PG_mlocked flag. I had removed this in favor of the PG_unevictable flag + an mlock_count [new page struct member]. I restored the PG_mlocked flag to eliminate the new count field. 2) add the mlock/unevictable infrastructure to mm/mlock.c, with internal APIs in mm/internal.h. This is a rework of Nick's original patch to these files, taking into account that mlocked pages are now kept on unevictable LRU list. 3) update vmscan.c:page_evictable() to check PageMlocked() and, if vma passed in, the vm_flags. Note that the vma will only be passed in for new pages in the fault path; and then only if the "cull unevictable pages in fault path" patch is included. 4) add try_to_unlock() to rmap.c to walk a page's rmap and ClearPageMlocked() if no other vmas have it mlocked. Reuses as much of try_to_unmap() as possible. This effectively replaces the use of one of the lru list links as an mlock count. If this mechanism let's pages in mlocked vmas leak through w/o PG_mlocked set [I don't know that it does], we should catch them later in try_to_unmap(). One hopes this will be rare, as it will be relatively expensive. Original mm/internal.h, mm/rmap.c and mm/mlock.c changes: Signed-off-by: Nick Piggin <npiggin@suse.de> splitlru: introduce __get_user_pages(): New munlock processing need to GUP_FLAGS_IGNORE_VMA_PERMISSIONS. because current get_user_pages() can't grab PROT_NONE pages theresore it cause PROT_NONE pages can't munlock. [akpm@linux-foundation.org: fix this for pagemap-pass-mm-into-pagewalkers.patch] [akpm@linux-foundation.org: untangle patch interdependencies] [akpm@linux-foundation.org: fix things after out-of-order merging] [hugh@veritas.com: fix page-flags mess] [lee.schermerhorn@hp.com: fix munlock page table walk - now requires 'mm'] [kosaki.motohiro@jp.fujitsu.com: build fix] [kosaki.motohiro@jp.fujitsu.com: fix truncate race and sevaral comments] [kosaki.motohiro@jp.fujitsu.com: splitlru: introduce __get_user_pages()] Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Signed-off-by: Rik van Riel <riel@redhat.com> Signed-off-by: Lee Schermerhorn <lee.schermerhorn@hp.com> Cc: Nick Piggin <npiggin@suse.de> Cc: Dave Hansen <dave@linux.vnet.ibm.com> Cc: Matt Mackall <mpm@selenic.com> Signed-off-by: Hugh Dickins <hugh@veritas.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* nommu: Provide vmalloc_exec().Paul Mundt2008-08-04
| | | | | | | | Now that SH has switched to vmalloc_exec() for PAGE_KERNEL_EXEC usage, it's apparent that nommu has no vmalloc_exec() definition of its own. Stub in the one from mm/vmalloc.c. Signed-off-by: Paul Mundt <lethal@linux-sh.org>
* tracehook: tracehook_expect_breakpointsRoland McGrath2008-07-26
| | | | | | | | | | | | This adds tracehook_expect_breakpoints() as a formal hook for the nommu code to use for its, "Is text-poking likely?" check at mmap time. This names the actual semantics the code means to test, and documents it. Signed-off-by: Roland McGrath <roland@redhat.com> Cc: Oleg Nesterov <oleg@tv-sign.ru> Reviewed-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* nommu: Correct kobjsize() page validity checks.Paul Mundt2008-06-12
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This implements a few changes on top of the recent kobjsize() refactoring introduced by commit 6cfd53fc03670c7a544a56d441eb1a6cc800d72b. As Christoph points out: virt_to_head_page cannot return NULL. virt_to_page also does not return NULL. pfn_valid() needs to be used to figure out if a page is valid. Otherwise the page struct reference that was returned may have PageReserved() set to indicate that it is not a valid page. As discussed further in the thread, virt_addr_valid() is the preferable way to validate the object pointer in this case. In addition to fixing up the reserved page case, it also has the benefit of encapsulating the hack introduced by commit 4016a1390d07f15b267eecb20e76a48fd5c524ef on the impacted platforms, allowing us to get rid of the extra checking in kobjsize() for the platforms that don't perform this type of bizarre memory_end abuse (every nommu platform that isn't blackfin). If blackfin decides to get in line with every other platform and use PageReserved for the DMA pages in question, kobjsize() will also continue to work fine. It also turns out that compound_order() will give us back 0-order for non-head pages, so we can get rid of the PageCompound check and just use compound_order() directly. Clean that up while we're at it. Signed-off-by: Paul Mundt <lethal@linux-sh.org> Reviewed-by: Christoph Lameter <clameter@sgi.com> Acked-by: David Howells <dhowells@redhat.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* nommu: fix kobjsize() for SLOB and SLUBPaul Mundt2008-06-06
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | kobjsize() has been abusing page->index as a method for sorting out compound order, which blows up both for page cache pages, and SLOB's reuse of the index in struct slob_page. Presently we are not able to accurately size arbitrary pointers that don't come from kmalloc(), so the best we can do is sort out the compound order from the head page if it's a compound page, or default to 0-order if it's impossible to ksize() the object. Obviously this leaves quite a bit to be desired in terms of object sizing accuracy, but the behaviour is unchanged over the existing implementation, while fixing the page->index oopses originally reported here: http://marc.info/?l=linux-mm&m=121127773325245&w=2 Accuracy could also be improved by having SLUB and SLOB both set PG_slab on ksizeable pages, rather than just handling the __GFP_COMP cases irregardless of the PG_slab setting, as made possibly with Pekka's patches: http://marc.info/?l=linux-kernel&m=121139439900534&w=2 http://marc.info/?l=linux-kernel&m=121139440000537&w=2 http://marc.info/?l=linux-kernel&m=121139440000540&w=2 This is primarily a bugfix for nommu systems for 2.6.26, with the aim being to gradually kill off kobjsize() and its particular brand of object abuse entirely. Reviewed-by: Pekka Enberg <penberg@cs.helsinki.fi> Signed-off-by: Paul Mundt <lethal@linux-sh.org> Acked-by: David Howells <dhowells@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm: fix atomic_t overflow in vmAlan Cox2008-05-24
| | | | | | | | | | The atomic_t type is 32bit but a 64bit system can have more than 2^32 pages of virtual address space available. Without this we overflow on ludicrously large mappings Signed-off-by: Alan Cox <alan@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* procfs task exe symlinkMatt Helsley2008-04-29
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | The kernel implements readlink of /proc/pid/exe by getting the file from the first executable VMA. Then the path to the file is reconstructed and reported as the result. Because of the VMA walk the code is slightly different on nommu systems. This patch avoids separate /proc/pid/exe code on nommu systems. Instead of walking the VMAs to find the first executable file-backed VMA we store a reference to the exec'd file in the mm_struct. That reference would prevent the filesystem holding the executable file from being unmounted even after unmapping the VMAs. So we track the number of VM_EXECUTABLE VMAs and drop the new reference when the last one is unmapped. This avoids pinning the mounted filesystem. [akpm@linux-foundation.org: improve comments] [yamamoto@valinux.co.jp: fix dup_mmap] Signed-off-by: Matt Helsley <matthltc@us.ibm.com> Cc: Oleg Nesterov <oleg@tv-sign.ru> Cc: David Howells <dhowells@redhat.com> Cc:"Eric W. Biederman" <ebiederm@xmission.com> Cc: Christoph Hellwig <hch@lst.de> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Hugh Dickins <hugh@veritas.com> Signed-off-by: YAMAMOTO Takashi <yamamoto@valinux.co.jp> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm/nommu.c: return 0 from kobjsize with invalid objectsMichael Hennerich2008-04-28
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Don't perform kobjsize operations on objects the kernel doesn't manage. On Blackfin, drivers can get dma coherent memory by calling a function dma_alloc_coherent(). We do this in nommu by configuring a chunk of uncached memory at the top of memory. Since we don't want the kernel to use the uncached memory, we lie to the kernel, and tell it that it's max memory is between 0, and the start of the uncached dma coherent section. this all works well, until this memory gets exposed into userspace (with a frame buffer), when you look at the process's maps, it shows the framebuf: root:/proc> cat maps [snip] 03f0ef00-03f34700 rw-p 00000000 1f:00 192 /dev/fb0 root:/proc> This is outside the "normal" range for the kernel. When the kernel tries to find the size of this object (when you run ps), it dies in nommu.c in kobjsize. BUG_ON(page->index >= MAX_ORDER); since the page we are referring to is outside what the kernel thinks is it's max valid memory. root:~> while [ 1 ]; ps > /dev/null; done kernel BUG at mm/nommu.c:119! Kernel panic - not syncing: BUG! We fixed this by adding a check to reject out of range object pointers as it already does that for NULL pointers. Signed-off-by: Michael Hennerich <Michael.Hennerich@analog.com> Signed-off-by: Robin Getz <rgetz@blackfin.uclinux.org> Acked-by: David Howells <dhowells@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* nommu: add new vmalloc_user() and remap_vmalloc_range() interfaces.Paul Mundt2008-02-05
| | | | | | | | | | | | | | | | | | | | | | This builds on top of the earlier vmalloc_32_user() work introduced by b50731732f926d6c49fd0724616a7344c31cd5cf, as we now have places in the nommu allmodconfig that hit up against these missing APIs. As vmalloc_32_user() is already implemented, this is moved over to vmalloc_user() and simply made a wrapper. As all current nommu platforms are 32-bit addressable, there's no special casing we have to do for ZONE_DMA and things of that nature as per GFP_VMALLOC32. remap_vmalloc_range() needs to check VM_USERMAP in order to figure out whether we permit the remap or not, which means that we also have to rework the vmalloc_user() code to grovel for the VMA and set the flag. Signed-off-by: Paul Mundt <lethal@linux-sh.org> Acked-by: David McCullough <david_mccullough@securecomputing.com> Acked-by: David Howells <dhowells@redhat.com> Acked-by: Greg Ungerer <gerg@snapgear.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* vmalloc: add const to void* parametersChristoph Lameter2008-02-05
| | | | | | | | | | Make vmalloc functions work the same way as kfree() and friends that take a const void * argument. [akpm@linux-foundation.org: fix consts, coding-style] 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>
* Security: round mmap hint address above mmap_min_addrEric Paris2007-12-05
| | | | | | | | | | | | | | | | | | | If mmap_min_addr is set and a process attempts to mmap (not fixed) with a non-null hint address less than mmap_min_addr the mapping will fail the security checks. Since this is just a hint address this patch will round such a hint address above mmap_min_addr. gcj was found to try to be very frugal with vm usage and give hint addresses in the 8k-32k range. Without this patch all such programs failed and with the patch they happily get a higher address. This patch is wrappad in CONFIG_SECURITY since mmap_min_addr doesn't exist without it and there would be no security check possible no matter what. So we should not bother compiling in this rounding if it is just a waste of time. Signed-off-by: Eric Paris <eparis@redhat.com> Signed-off-by: James Morris <jmorris@namei.org>
* NOMMU: mm/nommu.c needs linux/module.hDavid Howells2007-10-29
| | | | | | | | mm/nommu.c needs to #include linux/module.h for it to understand EXPORT_*() macros. Signed-off-by: David Howells <dhowells@redhat.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* Explain clearly why kmalloc() can't use __GFP_HIGHMEM.Robert P. J. Day2007-10-19
| | | | | | | | Fix the wishy-washy comment to clearly explain why kmalloc() can't use the __GFP_HIGHMEM zone modifier. Signed-off-by: Robert P. J. Day <rpjday@mindspring.com> Signed-off-by: Adrian Bunk <bunk@kernel.org>
* security/ cleanupsAdrian Bunk2007-10-17
| | | | | | | | | | | | | | | | This patch contains the following cleanups that are now possible: - remove the unused security_operations->inode_xattr_getsuffix - remove the no longer used security_operations->unregister_security - remove some no longer required exit code - remove a bunch of no longer used exports Signed-off-by: Adrian Bunk <bunk@kernel.org> Acked-by: James Morris <jmorris@namei.org> Cc: Chris Wright <chrisw@sous-sol.org> Cc: Stephen Smalley <sds@tycho.nsa.gov> Cc: Serge Hallyn <serue@us.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* fix NULL pointer dereference in __vm_enough_memory()Alan Cox2007-08-22
| | | | | | | | | | | | | | | | | | | | The new exec code inserts an accounted vma into an mm struct which is not current->mm. The existing memory check code has a hard coded assumption that this does not happen as does the security code. As the correct mm is known we pass the mm to the security method and the helper function. A new security test is added for the case where we need to pass the mm and the existing one is modified to pass current->mm to avoid the need to change large amounts of code. (Thanks to Tobias for fixing rejects and testing) Signed-off-by: Alan Cox <alan@redhat.com> Cc: WU Fengguang <wfg@mail.ustc.edu.cn> Cc: James Morris <jmorris@redhat.com> Cc: Tobias Diedrich <ranma+kernel@tdiedrich.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* nommu: vmalloc_32_user()/vm_insert_page() and symbol exports.Paul Mundt2007-07-21
| | | | | | | | | | | | | | | | | Trying to survive an allmodconfig on a nommu platform results in many screen lengths of module unhappiness. Many of the mmap related things that binfmt_flat hooks in to are never exported despite being global, and there are also missing definitions for vmalloc_32_user() and vm_insert_page(). I've implemented vmalloc_32_user() trying to stick as close to the mm/vmalloc.c implementation as possible, though we don't have any need for VM_USERMAP, so groveling for the VMA can be skipped. vm_insert_page() has been stubbed for now in order to keep the build happy. Signed-off-by: Paul Mundt <lethal@linux-sh.org> Cc: David Howells <dhowells@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm: fault feedback #1Nick Piggin2007-07-19
| | | | | | | | | | | | | | | | | | | | | | | | Change ->fault prototype. We now return an int, which contains VM_FAULT_xxx code in the low byte, and FAULT_RET_xxx code in the next byte. FAULT_RET_ code tells the VM whether a page was found, whether it has been locked, and potentially other things. This is not quite the way he wanted it yet, but that's changed in the next patch (which requires changes to arch code). This means we no longer set VM_CAN_INVALIDATE in the vma in order to say that a page is locked which requires filemap_nopage to go away (because we can no longer remain backward compatible without that flag), but we were going to do that anyway. struct fault_data is renamed to struct vm_fault as Linus asked. address is now a void __user * that we should firmly encourage drivers not to use without really good reason. The page is now returned via a page pointer in the vm_fault struct. Signed-off-by: Nick Piggin <npiggin@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm: merge populate and nopage into fault (fixes nonlinear)Nick Piggin2007-07-19
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Nonlinear mappings are (AFAIKS) simply a virtual memory concept that encodes the virtual address -> file offset differently from linear mappings. ->populate is a layering violation because the filesystem/pagecache code should need to know anything about the virtual memory mapping. The hitch here is that the ->nopage handler didn't pass down enough information (ie. pgoff). But it is more logical to pass pgoff rather than have the ->nopage function calculate it itself anyway (because that's a similar layering violation). Having the populate handler install the pte itself is likewise a nasty thing to be doing. This patch introduces a new fault handler that replaces ->nopage and ->populate and (later) ->nopfn. Most of the old mechanism is still in place so there is a lot of duplication and nice cleanups that can be removed if everyone switches over. The rationale for doing this in the first place is that nonlinear mappings are subject to the pagefault vs invalidate/truncate race too, and it seemed stupid to duplicate the synchronisation logic rather than just consolidate the two. After this patch, MAP_NONBLOCK no longer sets up ptes for pages present in pagecache. Seems like a fringe functionality anyway. NOPAGE_REFAULT is removed. This should be implemented with ->fault, and no users have hit mainline yet. [akpm@linux-foundation.org: cleanup] [randy.dunlap@oracle.com: doc. fixes for readahead] [akpm@linux-foundation.org: build fix] Signed-off-by: Nick Piggin <npiggin@suse.de> Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com> Cc: Mark Fasheh <mark.fasheh@oracle.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* nommu: stub expand_stack() for nommu caseGreg Ungerer2007-07-16
| | | | | | | | | | Be consistent with VM mmap, implement expand_stack(). We can't actually do anything other than return an error in the no MMU case though. Signed-off-by: Greg Ungerer <gerg@uclinux.org> Cc: David Howells <dhowells@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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