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2007-02-19Merge git://git.kernel.org/pub/scm/linux/kernel/git/bunk/trivialLinus Torvalds1-1/+1
* git://git.kernel.org/pub/scm/linux/kernel/git/bunk/trivial: (25 commits) Documentation/kernel-docs.txt update. arch/cris: typo in KERN_INFO Storage class should be before const qualifier kernel/printk.c: comment fix update I/O sched Kconfig help texts - CFQ is now default, not AS. Remove duplicate listing of Cris arch from README kbuild: more doc. cleanups doc: make doc. for maxcpus= more visible drivers/net/eexpress.c: remove duplicate comment add a help text for BLK_DEV_GENERIC correct a dead URL in the IP_MULTICAST help text fix the BAYCOM_SER_HDX help text fix SCSI_SCAN_ASYNC help text trivial documentation patch for platform.txt Fix typos concerning hierarchy Fix comment typo "spin_lock_irqrestore". Fix misspellings of "agressive". drivers/scsi/a100u2w.c: trivial typo patch Correct trivial typo in log2.h. Remove useless FIND_FIRST_BIT() macro from cardbus.c. ...
2007-02-18Merge NetSilicon NS93xx treeRussell King1-2/+2
Fixed conflicts: arch/arm/Makefile arch/arm/mm/Kconfig Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2007-02-17Merge AT91, EP93xx, General devel, PXA, S3C, V6+ and Xscale treesRussell King8-95/+228
2007-02-17[ARM] 4210/1: base for new machine type "NetSilicon NS9360"Uwe Kleine-König1-2/+2
Signed-off-by: Uwe Kleine-König <ukleinek@informatik.uni-freiburg.de> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2007-02-17kbuild: Replace remaining "depends" with "depends on"Robert P. J. Day1-1/+1
Replace the very few remaining "depends" Kconfig directives with "depends on". Signed-off-by: Robert P. J. Day <rpjday@mindspring.com> Signed-off-by: Adrian Bunk <bunk@stusta.de>
2007-02-16[ARM] 4191/1: Remove redundant __flush_dcache_page() function prototypeGeorge G. Davis1-2/+0
Commit 1c9d3df5e88ad7db23f5b22f4341c39722a904a4 added function prototype __flush_dcache_page() in include/asm-arm/cacheflush.h. So we can remove the prototype for same in arch/arm/mm/fault-armv.c since it is now redundant to have it there. Signed-off-by: George G. Davis <gdavis@mvista.com> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2007-02-15Merge Realview GIC codeRussell King1-3/+5
2007-02-15[ARM] 4109/2: Add support for the RealView/EB MPCore revC platformCatalin Marinas1-3/+5
The kernel originally supported revB only. This patch enables revC by default and adds a config option for building the kernel for the revB platform. Since the SCU base address was hard-coded in the proc-v6.S file (and only valid for RealView/EB revB), this patch also adds a more generic support for defining the SCU information. Signed-off-by: Catalin Marinas <catalin.marinas@arm.com> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2007-02-11[ARM] 4158/1: Fix user page protection macrosImre_Deak1-0/+3
The PAGE_* user page protection macros don't take into account the configured memory policy and other architecture specific bits like the global/ASID and shared mapping bits. Instead of constants let these depend on a variable fixed up at init just like PAGE_KERNEL. Signed-off-by: Imre Deak <imre.deak@solidboot.com> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2007-02-11[ARM] 4135/1: Add support for the L210/L220 cache controllersCatalin Marinas3-0/+110
This patch adds the support for the L210/L220 (outer) cache controller. The cache range operations are done by index/way since L2 cache controller only accepts physical addresses. Signed-off-by: Catalin Marinas <catalin.marinas@arm.com> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2007-02-08[ARM] Always mark ARMv6 PTWs outer cacheableRussell King1-6/+8
Other platforms other than SMP may have an outer cache. For these, we also need to mark the page table walks outer cacheable. Since marking the walks always outer cacheable apparantly has no side effects, we might as well always mark them so. However, we continue to only mark PTWs shared if we have SMP enabled. Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2007-02-08[ARM] 4153/1: fix consistent_sync() off-by-one BUG checkLennert Buytenhek1-1/+1
In consistent_sync(), start + size can end up pointing one byte beyond the end of the direct RAM mapping. We shouldn't BUG() when this happens. Signed-off-by: Lennert Buytenhek <buytenh@wantstofly.org> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2007-02-08[ARM] 4145/2: AT91: Add support for AT91SAM9263 processorAndrew Victor1-2/+2
Add support for the Atmel AT91SAM9263 processor. It is similar to the AT91SAM9260 but with more integrated peripherals, 5 GPIO banks, etc. Original patch from Nicolas Ferre. Signed-off-by: Andrew Victor <andrew@sanpeople.com> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2007-02-08[ARM] Convert DMA cache handling to take const void * argsRussell King1-7/+6
The DMA cache handling functions take virtual addresses, but in the form of unsigned long arguments. This leads to a little confusion about what exactly they take. So, convert them to take const void * instead. Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2007-02-08[ARM] 4134/1: Add generic support for outer cachesCatalin Marinas2-0/+9
The outer cache can be L2 as on RealView/EB MPCore platform or even L3 or further on ARMv7 cores. This patch adds the generic support for flushing the outer cache in the DMA operations. Signed-off-by: Catalin Marinas <catalin.marinas@arm.com> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2007-02-08[ARM] 4129/1: Add barriers after the TLB operationsCatalin Marinas1-0/+4
The architecture specification states that TLB operations are guaranteed to be complete only after the execution of a DSB (Data Synchronisation Barrier, former Data Write Barrier or Drain Write Buffer). The branch target cache invalidation is also needed. The ISB (Instruction Synchronisation Barrier, formerly Prefetch Flush) is needed unless there will be a return from exception before the corresponding mapping is used (i.e. user mappings). Signed-off-by: Catalin Marinas <catalin.marinas@arm.com> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2007-02-08[ARM] 4128/1: Architecture compliant TTBR changing sequenceCatalin Marinas1-2/+10
On newer architectures (ARMv6, ARMv7), the depth of the prefetch and branch prediction is implementation defined and there is a small risk of wrong ASID tagging when changing TTBR0 before setting the new context id. The recommended solution is to set a reserved ASID during TTBR changing. This patch reserves ASID 0. Signed-off-by: Catalin Marinas <catalin.marinas@arm.com> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2007-02-08[ARM] 4123/1: xsc3: general cleanupLennert Buytenhek1-76/+75
This patch cleans up proc-xsc3: - Correct a number of typos. - Fix up indentation in a number of places. - Change references to the various caches to be more clear about whether we're talking about the L1 D, the L1 I or the unified L2 cache. - Rename "drain write buffer" to "data write barrier", the official name used in the Manzano manual. - Change the xsc3 cpu name from "XScale-Core3" to "XScale-V3 based processor". Also, since a previously merged patch implements proper support for using a MAC or iWMMXt coprocessor on xsc3 platforms, we no longer need to enable access to CP0 on boot. Signed-off-by: Lennert Buytenhek <buytenh@wantstofly.org> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2007-01-25[ARM] 4112/1: Only ioremap to supersections if DOMAIN_IO is zeroCatalin Marinas1-1/+2
Supersections do not have a field for the domain and it is always 0. This patch prevents the creation of supersections during ioremap when DOMAIN_IO is not zero (i.e. !defined(CONFIG_IO_36)). Signed-off-by: Catalin Marinas <catalin.marinas@arm.com> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2007-01-24[ARM] 4100/1: iop3xx: fix cpu mask for iop333Dan Williams1-1/+1
cosmetic fix so iop333 is not reported as ixp46x iop333 cpuid = 0x69054210 Signed-off-by: Dan Williams <dan.j.williams@intel.com> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2007-01-24[ARM] Fix show_mem() for discontigmemRussell King1-4/+7
show_mem() was assuming incorrectly that the mem_map for any node started at PFN 0. This is obviously wrong; fix it to take account of node_start_pfn. Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2007-01-08[ARM] Resolve fuse and direct-IO failures due to missing cache flushesRussell King1-0/+39
fuse does not work on ARM due to cache incoherency issues - fuse wants to use get_user_pages() to copy data from the current process into kernel space. However, since this accesses userspace via the kernel mapping, the kernel mapping can be out of date wrt data written to userspace. This can lead to unpredictable behaviour (in the case of fuse) or data corruption for direct-IO. This resolves debian bug #402876 Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2006-12-30[ARM] 4078/1: Fix ARM copypage cache coherency problemsRichard Purdie3-0/+16
If PG_dcache_dirty is set for a page, we need to flush the source page before performing any copypage operation using a different virtual address. This fixes the copypage implementations for XScale, StrongARM and ARMv6. This patch fixes segmentation faults seen in the dynamic linker under the usage patterns in glibc 2.4/2.5. Signed-off-by: Richard Purdie <rpurdie@rpsys.net> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2006-12-19[ARM] 4061/1: xsc3: change of maintainerLennert Buytenhek1-1/+1
Deepak Saxena has agreed to hand xsc3 maintainership over to me. Signed-off-by: Lennert Buytenhek <buytenh@wantstofly.org> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2006-12-18[ARM] Fix warnings from asm/system.hRussell King1-0/+20
Move adjust_cr() into arch/arm/mm/mmu.c, and move irqflags.h to a more appropriate place in the header file. Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2006-12-17[ARM] Fix BUG()s in ioremap() codeRussell King1-0/+2
We need to ensure that the area size is page aligned so that remap_area_pte() doesn't increment the address past the end of the desired area. Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2006-12-13[ARM] Clean up ioremap codeRussell King1-58/+40
Since we're keeping the ioremap code, we might as well keep it as close to the standard kernel as possible. Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2006-12-13[ARM] Unuse another Linux PTE bitRussell King25-75/+71
L_PTE_ASID is not really required to be stored in every PTE, since we can identify it via the address passed to set_pte_at(). So, create set_pte_ext() which takes the address of the PTE to set, the Linux PTE value, and the additional CPU PTE bits which aren't encoded in the Linux PTE value. Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2006-12-08[ARM] Formalise the ARMv6 processor name stringRussell King1-1/+1
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2006-12-08[ARM] Handle HWCAP_VFP in VFP support codeRussell King2-7/+2
Don't set HWCAP_VFP in the processor support file; not only does it depend on the processor features, but it also depends on the support code being present. Therefore, only set it if the support code detects that we have a VFP coprocessor attached. Also, move the VFP handling of the coprocessor access register into the VFP support code. Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2006-12-07Merge branch 'for-linus' of master.kernel.org:/home/rmk/linux-2.6-armLinus Torvalds24-39/+43
* 'for-linus' of master.kernel.org:/home/rmk/linux-2.6-arm: (76 commits) [ARM] 4002/1: S3C24XX: leave parent IRQs unmasked [ARM] 4001/1: S3C24XX: shorten reboot time [ARM] 3983/2: remove unused argument to __bug() [ARM] 4000/1: Osiris: add third serial port in [ARM] 3999/1: RX3715: suspend to RAM support [ARM] 3998/1: VR1000: LED platform devices [ARM] 3995/1: iop13xx: add iop13xx support [ARM] 3968/1: iop13xx: add iop13xx_defconfig [ARM] Update mach-types [ARM] Allow gcc to optimise arm_add_memory a little more [ARM] 3991/1: i.MX/MX1 high resolution time source [ARM] 3990/1: i.MX/MX1 more precise PLL decode [ARM] 3986/1: H1940: suspend to RAM support [ARM] 3985/1: ixp4xx clocksource cleanup [ARM] 3984/1: ixp4xx/nslu2: Fix disk LED numbering (take 2) [ARM] 3994/1: ixp23xx: fix handling of pci master aborts [ARM] 3981/1: sched_clock for PXA2xx [ARM] 3980/1: extend the ARM Versatile sched_clock implementation from 32 to 63 bit [ARM] 3979/1: extend the SA11x0 sched_clock implementation from 32 to 63 bit period [ARM] 3978/1: macro to provide a 63-bit value from a 32-bit hardware counter ...
2006-12-07[ARM] Merge individual ARM sub-treesRussell King24-39/+43
Merge: Atmel AT91RM9200 and AT91SAM9260 changes General ARM developments Disconfiguous memory cleanups 64-bit/32-bit division and sched_clock extension patches EP93xx support changes IOP support changes Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2006-12-07[ARM] 3999/1: RX3715: suspend to RAM supportBen Dooks1-1/+3
The RX3715 is similar to the H1940 in the way that suspend to RAM works, so we can use most of the extant support for the H1940 with only a few modifictions Signed-off-by: Ben Dooks <ben-linux@fluff.org> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2006-12-07[ARM] 3995/1: iop13xx: add iop13xx supportDan Williams1-1/+1
The iop348 processor integrates an Xscale (XSC3 512KB L2 Cache) core with a Serial Attached SCSI (SAS) controller, multi-ported DDR2 memory controller, 3 Application Direct Memory Access (DMA) controllers, a 133Mhz PCI-X interface, a x8 PCI-Express interface, and other peripherals to form a system-on-a-chip RAID subsystem engine. The iop342 processor replaces the SAS controller with a second Xscale core for dual core embedded applications. The iop341 processor is the single core version of iop342. This patch supports the two Intel customer reference platforms iq81340mc for external storage and iq81340sc for direct attach (HBA) development. The developer's manual is available here: ftp://download.intel.com/design/iio/docs/31503701.pdf Changelog: * removed virtual addresses from resource definitions * cleaned up some unnecessary #include's Signed-off-by: Dan Williams <dan.j.williams@intel.com> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2006-12-07[PATCH] mm: arch do_page_fault() vs in_atomic()Peter Zijlstra1-1/+1
In light of the recent pagefault and filemap_copy_from_user work I've gone through all the arch pagefault handlers to make sure the inc_preempt_count() 'feature' works as expected. Several sections of code (including the new filemap_copy_from_user) rely on the fact that faults do not take locks under increased preempt count. arch/x86_64 - good arch/powerpc - good arch/cris - fixed arch/i386 - good arch/parisc - fixed arch/sh - good arch/sparc - good arch/s390 - good arch/m68k - fixed arch/ppc - good arch/alpha - fixed arch/mips - good arch/sparc64 - good arch/ia64 - good arch/arm - fixed arch/um - good arch/avr32 - good arch/h8300 - NA arch/m32r - good arch/v850 - good arch/frv - fixed arch/m68knommu - NA arch/arm26 - fixed arch/sh64 - fixed arch/xtensa - good Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Acked-by: Nick Piggin <npiggin@suse.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-12-07[ARM] 3986/1: H1940: suspend to RAM supportBen Dooks1-0/+5
Add support to suspend and resume, using the H1940's bootloader Signed-off-by: Ben Dooks <ben-linux@fluff.org> Signed-off-by: Arnaud Patard <arnaud.patard@rtp-net.org> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2006-12-03[ARM] 3881/4: xscale: clean up cp0/cp1 handlingLennert Buytenhek1-7/+2
XScale cores either have a DSP coprocessor (which contains a single 40 bit accumulator register), or an iWMMXt coprocessor (which contains eight 64 bit registers.) Because of the small amount of state in the DSP coprocessor, access to the DSP coprocessor (CP0) is always enabled, and DSP context switching is done unconditionally on every task switch. Access to the iWMMXt coprocessor (CP0/CP1) is enabled only when an iWMMXt instruction is first issued, and iWMMXt context switching is done lazily. CONFIG_IWMMXT is supposed to mean 'the cpu we will be running on will have iWMMXt support', but boards are supposed to select this config symbol by hand, and at least one pxa27x board doesn't get this right, so on that board, proc-xscale.S will incorrectly assume that we have a DSP coprocessor, enable CP0 on boot, and we will then only save the first iWMMXt register (wR0) on context switches, which is Bad. This patch redefines CONFIG_IWMMXT as 'the cpu we will be running on might have iWMMXt support, and we will enable iWMMXt context switching if it does.' This means that with this patch, running a CONFIG_IWMMXT=n kernel on an iWMMXt-capable CPU will no longer potentially corrupt iWMMXt state over context switches, and running a CONFIG_IWMMXT=y kernel on a non-iWMMXt capable CPU will still do DSP context save/restore. These changes should make iWMMXt work on PXA3xx, and as a side effect, enable proper acc0 save/restore on non-iWMMXt capable xsc3 cores such as IOP13xx and IXP23xx (which will not have CONFIG_CPU_XSCALE defined), as well as setting and using HWCAP_IWMMXT properly. Signed-off-by: Lennert Buytenhek <buytenh@wantstofly.org> Acked-by: Dan Williams <dan.j.williams@intel.com> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2006-12-01[ARM] 3967/1: xsc3: make branch predication configurable on xsc3Dan Williams2-8/+1
Remove BTB_ENABLE from proc-xsc3.S On some early revisions of xsc3 enabling the branch target buffer can cause crashes, see erratum #42. Cc: Lennert Buytenhek <buytenh@wantstofly.org> Signed-off-by: Dan Williams <dan.j.williams@intel.com> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2006-12-01[ARM] 3971/1: xsc3: get rid of L_PTE_COHERENTLennert Buytenhek2-2/+4
Merge L_PTE_COHERENT with L_PTE_SHARED and free up a L_PTE_* bit. Signed-off-by: Lennert Buytenhek <buytenh@wantstofly.org> Signed-off-by: Dan Williams <dan.j.williams@intel.com> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2006-11-30[ARM] Fix nommu buildRussell King2-1/+8
Fix warnings and errors in arch/arm/mm for nommu build. Remove commented out function prototype in pgtable-nommu.h Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2006-11-30[ARM] Include asm/elf.h instead of asm/procinfo.hRussell King20-20/+20
These files want to provide/access ELF hwcap information, so should be including asm/elf.h rather than asm/procinfo.h Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2006-11-30Fix misc Kconfig typosMatt LaPlante1-1/+1
Fix various Kconfig typos. Signed-off-by: Matt LaPlante <kernel1@cyberdogtech.com> Acked-by: Randy Dunlap <randy.dunlap@oracle.com> Signed-off-by: Adrian Bunk <bunk@stusta.de>
2006-11-22[ARM] 3942/1: ARM: comment: consistent_sync should not be called directlyDan Williams1-0/+3
/* * Note: Drivers should NOT use this function directly, as it will break * platforms with CONFIG_DMABOUNCE. * Use the driver DMA support - see dma-mapping.h (dma_sync_*) */ Signed-off-by: Dan Williams <dan.j.williams@intel.com> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2006-11-07[ARM] 3927/1: Allow show_mem() to work with holes in memory map.Ray Lehtiniemi1-27/+34
show_mem() was not correctly handling holes in the memory map. It was treating the freed sections of the map as though they contained valid struct page entries. This could cause incorrect debugging output or even a kernel panic. This patch keeps the struct meminfo around after system initialization so that show_mem() can use it when scanning memory. show_mem() now walks over each bank of each online node, rather than assuming that each node contains a single contiguous bank. Signed-off-by: Ray Lehtiniemi <rayl@mail.com> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2006-11-02[ARM] 3912/1: Make PXA270 advertise HWCAP_IWMMXT capabilityPaul Gortmaker1-1/+1
ARM patch 3756/1 added HWCAP_IWMMXT. This patch adds support for broadcasting that info via /proc/cpuinfo and sets it for the CPU features of the PXA270. I've booted 19rc3 on a pxa270 and confirmed that the /proc/cpuinfo shows "iwmmxt" in the Features. Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com> Signed-off-by: Nicolas Pitre <nico@cam.org> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2006-10-08[PATCH] arm: it's OK to pass pointer to volatile as iounmap() argument...Al Viro1-3/+3
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-10-03Merge branch 'devel' of master.kernel.org:/home/rmk/linux-2.6-armLinus Torvalds1-1/+1
* 'devel' of master.kernel.org:/home/rmk/linux-2.6-arm: [ARM] 3848/1: pxafb: Add option of fixing video modes and spitz QVGA mode support [ARM] 3880/1: remove the last trace of iop31x support [ARM] 3879/1: ep93xx: instantiate platform devices for ep93xx ethernet [ARM] 3809/3: get rid of 4 megabyte kernel image size limit [ARM] Fix XIP_KERNEL build error in arch/arm/mm/mmu.c [ARM] 3874/1: Remove leftover usage of asm/timeofday.h
2006-09-30[ARM] Fix XIP_KERNEL build error in arch/arm/mm/mmu.cRussell King1-1/+1
XIP kernels need to know the start/end of text, but we were missing the declaration of _etext in mmu.c. Add it. Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2006-09-29[PATCH] pidspace: is_init()Sukadev Bhattiprolu1-1/+1
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>
2006-09-29[PATCH] make PROT_WRITE imply PROT_READJason Baron1-1/+1
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>