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* perf: Enable building perf tools for MetaJames Hogan2013-03-021-0/+6
| | | | | | | | | | | Define rmb(), cpu_relax(), and CPUINFO_PROC for Meta so that the perf tools can be built for Meta. Signed-off-by: James Hogan <james.hogan@imgtec.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Paul Mackerras <paulus@samba.org> Cc: Ingo Molnar <mingo@redhat.com> Cc: Arnaldo Carvalho de Melo <acme@ghostprotocols.net>
* metag: add boot time LNKGET/LNKSET checkJames Hogan2013-03-021-0/+79
| | | | | | | | | | | | | | | | Add boot time check for whether LNKGET/LNKSET go through or around the cache. Depending on the configuration an info message (no harm), warning (technically wrong but no harm), or big WARN (expect failure in either kernel or userland) may be emitted if the behaviour is not as expected: Configuration Hardware Response ------------------------------------------ -------- -------- AROUND_CACHE through pr_info !AROUND_CACHE && ATOMICITY_LNKGET around WARN (kernel) " && !ATOMICITY_LNKGET && SMP around WARN (user) " " && !SMP around pr_warn Signed-off-by: James Hogan <james.hogan@imgtec.com>
* metag: add __init to metag_cache_probe()James Hogan2013-03-021-1/+1
| | | | | | | metag_cache_probe() is only called from setup_arch(), so add the __init attribute to it. Signed-off-by: James Hogan <james.hogan@imgtec.com>
* metag: Add JTAG Debug Adapter (DA) supportJames Hogan2013-03-029-0/+105
| | | | | | | | | | | | Add basic JTAG Debug Adapter (DA) support so that drivers which communicate with the DA can detect whether one is actually present (otherwise the target will halt indefinitely). This allows the metag_da TTY driver and imgdafs filesystem driver to be built, updates defconfigs, and sets up the metag_da console early if it's configured in. Signed-off-by: James Hogan <james.hogan@imgtec.com>
* scripts/checkstack.pl: Add metag supportJames Hogan2013-03-021-2/+6
| | | | | | Adapt checkstack.pl so that it works for metag. Signed-off-by: James Hogan <james.hogan@imgtec.com>
* metag: ftrace supportJames Hogan2013-03-027-1/+248
| | | | | | | | | Add ftrace support for metag. Signed-off-by: James Hogan <james.hogan@imgtec.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Ingo Molnar <mingo@redhat.com> Reviewed-by: Steven Rostedt <rostedt@goodmis.org>
* metag: PerfJames Hogan2013-03-027-0/+1073
| | | | | | | | | | Add Perf support for metag. Signed-off-by: James Hogan <james.hogan@imgtec.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Paul Mackerras <paulus@samba.org> Cc: Ingo Molnar <mingo@redhat.com> Cc: Arnaldo Carvalho de Melo <acme@ghostprotocols.net>
* metag: Build infrastructureJames Hogan2013-03-0219-0/+1124
| | | | | | Add metag build infrastructure. Signed-off-by: James Hogan <james.hogan@imgtec.com>
* Kconfig.debug: add METAG to dependency listsJames Hogan2013-03-021-2/+2
| | | | | | | | | | | | | Add [!]METAG to a couple of Kconfig dependencies in lib/Kconfig.debug. Don't allow stack utilization instrumentation on metag, and allow building with frame pointers. Signed-off-by: James Hogan <james.hogan@imgtec.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: "Paul E. McKenney" <paul.mckenney@linaro.org> Cc: Akinobu Mita <akinobu.mita@gmail.com> Cc: Michel Lespinasse <walken@google.com> Cc: Catalin Marinas <catalin.marinas@arm.com>
* mm: define VM_GROWSUP for CONFIG_METAGJames Hogan2013-03-021-0/+2
| | | | | | | | | | | | | | | | | | Commit cc2383ec06be093789469852e1fe96e1148e9a2c ("mm: introduce arch-specific vma flag VM_ARCH_1") merged in v3.7-rc1. The above commit combined several arch-specific vma flags into one, and in the process it changed the VM_GROWSUP definition to depend on specific architectures rather than CONFIG_STACK_GROWSUP. Therefore add an ifdef for CONFIG_METAG to also set VM_GROWSUP. Signed-off-by: James Hogan <james.hogan@imgtec.com> Cc: Konstantin Khlebnikov <khlebnikov@openvz.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Mel Gorman <mgorman@suse.de> Cc: Michel Lespinasse <walken@google.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: linux-mm@kvack.org
* metag: Various other headersJames Hogan2013-03-0211-0/+526
| | | | | | | | | Add the remaining metag header files: - byteorder.h, swab.h (byte order and swapping) - barrier.h, cpu.h. hwthread.h, processor.h (hardware thread related) - bug.h, elf.h, gpio.h, linkage.h, resource.h (other) Signed-off-by: James Hogan <james.hogan@imgtec.com>
* metag: Stack unwindingJames Hogan2013-03-022-0/+207
| | | | | | Add stack unwinding support for metag. Signed-off-by: James Hogan <james.hogan@imgtec.com>
* metag: Optimised library functionsJames Hogan2013-03-0220-0/+1474
| | | | | | Add optimised library functions for metag. Signed-off-by: James Hogan <james.hogan@imgtec.com>
* metag: DMAJames Hogan2013-03-022-0/+690
| | | | | | Add DMA mapping code. Signed-off-by: James Hogan <james.hogan@imgtec.com>
* metag: SMP supportJames Hogan2013-03-029-0/+1064
| | | | | | | | Add SMP support for metag. This allows Linux to take control of multiple hardware threads on a single Meta core, treating them as separate Linux CPUs. Signed-off-by: James Hogan <james.hogan@imgtec.com>
* metag: Basic documentationJames Hogan2013-03-024-0/+266
| | | | | | | | | | | Add basic metag documentation. This includes an outline description of the ABIs (including syscall ABI) and calling conventions, similar to the one in Documentation/frv/. Signed-off-by: James Hogan <james.hogan@imgtec.com> Cc: Rob Landley <rob@landley.net> Cc: Al Viro <viro@ZenIV.linux.org.uk> Cc: linux-doc@vger.kernel.org
* metag: Atomics, locks and bitopsJames Hogan2013-03-0213-0/+1395
| | | | | | | | | | | | | | | | | | | | | | Add header files to implement Meta hardware thread locks (used by some other atomic operations), atomics, spinlocks, and bitops. There are 2 main types of atomic primitives for metag (in addition to IRQs off on UP): - LOCK instructions provide locking between hardware threads. - LNKGET/LNKSET instructions provide load-linked/store-conditional operations allowing for lighter weight atomics on Meta2 LOCK instructions allow for hardware threads to acquire voluntary or exclusive hardware thread locks: - LOCK0 releases exclusive and voluntary lock from the running hardware thread. - LOCK1 acquires the voluntary hardware lock, blocking until it becomes available. - LOCK2 implies LOCK1, and additionally acquires the exclusive hardware lock, blocking all other hardware threads from executing. Signed-off-by: James Hogan <james.hogan@imgtec.com>
* metag: Module supportJames Hogan2013-03-022-0/+321
| | | | Signed-off-by: James Hogan <james.hogan@imgtec.com>
* metag: Scheduling/Process managementJames Hogan2013-03-022-0/+616
| | | | Signed-off-by: James Hogan <james.hogan@imgtec.com>
* metag: System CallsJames Hogan2013-03-028-0/+508
| | | | | | | | | | | | | Add metag system call and gateway page interfaces. The metag architecture port uses the generic system call numbers from asm-generic/unistd.h, as well as a user gateway page mapped at 0x6ffff000 which contains fast atomic primitives (depending on SMP) and a fast method of accessing TLS data. System calls use the SWITCH instruction with the immediate 0x440001 to signal a system call. Signed-off-by: James Hogan <james.hogan@imgtec.com>
* metag: Internal and external irqchipsJames Hogan2013-03-028-0/+1359
| | | | | | | | | | | | | | | | | | | | | | | | Meta core internal interrupts (from HWSTATMETA and friends) are vectored onto the TR1 core trigger for the current thread. This is demultiplexed in irq-metag.c to individual Linux IRQs for each internal interrupt. External SoC interrupts (from HWSTATEXT and friends) are vectored onto the TR2 core trigger for the current thread. This is demultiplexed in irq-metag-ext.c to individual Linux IRQs for each external SoC interrupt. The external irqchip has devicetree bindings for configuring the number of irq banks and the type of masking available. Signed-off-by: James Hogan <james.hogan@imgtec.com> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Grant Likely <grant.likely@secretlab.ca> Cc: Rob Herring <rob.herring@calxeda.com> Cc: Rob Landley <rob@landley.net> Cc: Dom Cobley <popcornmix@gmail.com> Cc: Simon Arlott <simon@fire.lp0.eu> Cc: Viresh Kumar <viresh.kumar@linaro.org> Cc: Maxime Ripard <maxime.ripard@free-electrons.com> Cc: devicetree-discuss@lists.ozlabs.org Cc: linux-doc@vger.kernel.org
* metag: IRQ handlingJames Hogan2013-03-023-0/+444
| | | | | | | Add core IRQ handling for metag. The code in irq.c exposes the TBX signal numbers as Linux IRQs. Signed-off-by: James Hogan <james.hogan@imgtec.com>
* metag: TrapsJames Hogan2013-03-025-0/+1167
| | | | | | | | | | | | | Add trap code for metag. At the lowest level Meta traps (and return from interrupt instruction - RTI) simply swap the PC and PCX registers and optionally toggle the interrupt status bit (ISTAT). Low level TBX code in tbipcx.S handles the core context save, determine the TBX signal number based on the core trigger that fired (using the TXSTATI status register), and call TBX signal handlers (mostly in traps.c) via a vector table. Signed-off-by: James Hogan <james.hogan@imgtec.com> Cc: Al Viro <viro@zeniv.linux.org.uk>
* metag: Time keepingJames Hogan2013-03-0210-0/+378
| | | | | | | | | | | Add time keeping code for metag. Meta hardware threads have 2 timers. The background timer (TXTIMER) is used as a free-running time base, and the interrupt timer (TXTIMERI) is used for the timer interrupt. Both counters traditionally count at approximately 1MHz. Signed-off-by: James Hogan <james.hogan@imgtec.com> Cc: John Stultz <johnstul@us.ibm.com> Cc: Thomas Gleixner <tglx@linutronix.de>
* metag: ptraceJames Hogan2013-03-024-0/+555
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The ptrace interface for metag provides access to some core register sets using the PTRACE_GETREGSET and PTRACE_SETREGSET operations. The details of the internal context structures is abstracted into user API structures to both ease use and allow flexibility to change the internal context layouts. Copyin and copyout functions for these register sets are exposed to allow signal handling code to use them to copy to and from the signal context. struct user_gp_regs (NT_PRSTATUS) provides access to the core general purpose register context. struct user_cb_regs (NT_METAG_CBUF) provides access to the TXCATCH* registers which contains information abuot a memory fault, unaligned access error or watchpoint. This can be modified to alter the way the fault is replayed on resume ("catch replay"), or to prevent the replay taking place. struct user_rp_state (NT_METAG_RPIPE) provides access to the state of the Meta read pipeline which can be used to hide memory latencies in hand optimised data loops. Extended DSP register state, DSP RAM, and hardware breakpoint registers aren't yet exposed through ptrace. Signed-off-by: James Hogan <james.hogan@imgtec.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Denys Vlasenko <vda.linux@googlemail.com> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Tony Lindgren <tony@atomide.com> Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
* metag: Device treeJames Hogan2013-03-025-0/+160
| | | | | | | Add device tree files to arch/metag. Signed-off-by: James Hogan <james.hogan@imgtec.com> Reviewed-by: Vineet Gupta <vgupta@synopsys.com>
* metag: Signal handlingJames Hogan2013-03-023-0/+383
| | | | | | | Add signal handling code for metag. Signed-off-by: James Hogan <james.hogan@imgtec.com> Cc: Al Viro <viro@zeniv.linux.org.uk>
* metag: TCM supportJames Hogan2013-03-025-0/+317
| | | | | | Add some TCM support Signed-off-by: James Hogan <james.hogan@imgtec.com>
* metag: Highmem supportJames Hogan2013-03-023-0/+294
| | | | Signed-off-by: James Hogan <james.hogan@imgtec.com>
* metag: Huge TLBJames Hogan2013-03-022-0/+377
| | | | | | Add huge TLB support to the metag architecture. Signed-off-by: James Hogan <james.hogan@imgtec.com>
* metag: Memory handlingJames Hogan2013-03-025-0/+1904
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Meta has instructions for accessing: - bytes - GETB (1 byte) - words - GETW (2 bytes) - doublewords - GETD (4 bytes) - longwords - GETL (8 bytes) All accesses must be aligned. Unaligned accesses can be detected and made to fault on Meta2, however it isn't possible to fix up unaligned writes so we don't bother fixing up reads either. This patch adds metag memory handling code including: - I/O memory (io.h, ioremap.c): Actually any virtual memory can be accessed with these helpers. A part of the non-MMUable address space is used for memory mapped I/O. The ioremap() function is implemented one to one for non-MMUable addresses. - User memory (uaccess.h, usercopy.c): User memory is directly accessible from privileged code. - Kernel memory (maccess.c): probe_kernel_write() needs to be overwridden to use the I/O functions when doing a simple aligned write to non-writecombined memory, otherwise the write may be split by the generic version. Note that due to the fact that a portion of the virtual address space is non-MMUable, and therefore always maps directly to the physical address space, metag specific I/O functions are made available (metag_in32, metag_out32 etc). These cast the address argument to a pointer so that they can be used with raw physical addresses. These accessors are only to be used for accessing fixed core Meta architecture registers in the non-MMU region, and not for any SoC/peripheral registers. Signed-off-by: James Hogan <james.hogan@imgtec.com>
* metag: Memory managementJames Hogan2013-03-0210-0/+1833
| | | | | | | | | | | | | | | | | | | | | | | | Add memory management files for metag. Meta's 32bit virtual address space is split into two halves: - local (0x08000000-0x7fffffff): traditionally local to a hardware thread and incoherent between hardware threads. Each hardware thread has it's own local MMU table. On Meta2 the local space can be globally coherent (GCOn) if the cache partitions coincide. - global (0x88000000-0xffff0000): coherent and traditionally global between hardware threads. On Meta2, each hardware thread has it's own global MMU table. The low 128MiB of each half is non-MMUable and maps directly to the physical address space: - 0x00010000-0x07ffffff: contains Meta core registers and maps SoC bus - 0x80000000-0x87ffffff: contains low latency global core memories Linux usually further splits the local virtual address space like this: - 0x08000000-0x3fffffff: user mappings - 0x40000000-0x7fffffff: kernel mappings Signed-off-by: James Hogan <james.hogan@imgtec.com>
* metag: Cache/TLB handlingJames Hogan2013-03-027-0/+1277
| | | | | | | | | | | | | | | | | Add cache and TLB handling code for metag, including the required callbacks used by MM switches and DMA operations. Caches can be partitioned between the hardware threads and the global space, however this is usually configured by the bootloader so Linux doesn't make any changes to this configuration. TLBs aren't configurable, so only need consideration to flush them. On Meta1 the L1 cache was VIVT which required a full flush on MM switch. Meta2 has a VIPT L1 cache so it doesn't require the full flush on MM switch. Meta2 can also have a writeback L2 with hardware prefetch which requires some special handling. Support is optional, and the L2 can be detected and initialised by Linux. Signed-off-by: James Hogan <james.hogan@imgtec.com>
* metag: TBX sourceJames Hogan2013-03-0211-0/+2172
| | | | | | | | | | Add source files from the Thread Binary Interface (TBI) library which provides useful low level operations and traps/context management. Among other things it handles interrupt/exception/syscall entry (in tbipcx.S). Signed-off-by: James Hogan <james.hogan@imgtec.com>
* metag: TBX headerJames Hogan2013-03-021-0/+1425
| | | | | | | Add the main header for the Thread Binary Interface (TBI) library which provides useful low level operations and trap/context management. Signed-off-by: James Hogan <james.hogan@imgtec.com>
* metag: BootJames Hogan2013-03-026-0/+715
| | | | | | | | | | | | | | | | Add boot code for metag. Due to the multi-threaded nature of Meta it is not uncommon for an RTOS or bare metal application to be started on other hardware threads by the bootloader. Since there is a single MMU switch which affects all threads, the MMU is traditionally configured by the bootloader prior to starting Linux. The bootloader passes a structure to Linux which among other things contains information about memory regions which have been mapped. Linux then assumes control of the local heap memory region. A kernel arguments string pointer or a flattened device tree pointer can be provided in the third argument. Signed-off-by: James Hogan <james.hogan@imgtec.com>
* metag: Header for core memory mapped registersJames Hogan2013-03-021-0/+1106
| | | | | | | Add the header <asm/metag_mem.h> describing addresses, fields, and bits of various core memory mapped registers in the low non-MMU region. Signed-off-by: James Hogan <james.hogan@imgtec.com>
* metag: Headers for core arch constantsJames Hogan2013-03-022-0/+1261
| | | | | | | | | | | | | | | | Add a couple of header files containing core architecture constants. The first (<asm/metag_isa.h>) contains some constants relating to the instruction set, such as values to give to the CACHEW and CACHER instructions. The second (<asm/metag_regs.h>) contains constants for the core register units directly accessible to various instructions, and for the registers, fields, and bits in those units. The main units described are the control unit (CT.*), the trigger unit (TR.*), and the run-time trace unit (TT.*). Signed-off-by: James Hogan <james.hogan@imgtec.com>
* metag: Add MAINTAINERS entryJames Hogan2013-03-021-0/+7
| | | | | | | | | | | Add MAINTAINERS entry for the metag architecture port. Signed-off-by: James Hogan <james.hogan@imgtec.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Mauro Carvalho Chehab <mchehab@redhat.com> Cc: Cesar Eduardo Barros <cesarb@cesarb.net> Cc: Joe Perches <joe@perches.com> Cc: "David S. Miller" <davem@davemloft.net>
* trace/ring_buffer: handle 64bit aligned structsJames Hogan2013-03-021-2/+4
| | | | | | | | | | | | | | Some 32 bit architectures require 64 bit values to be aligned (for example Meta which has 64 bit read/write instructions). These require 8 byte alignment of event data too, so use !CONFIG_HAVE_64BIT_ALIGNED_ACCESS instead of !CONFIG_64BIT || CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS to decide alignment, and align buffer_data_page::data accordingly. Signed-off-by: James Hogan <james.hogan@imgtec.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Ingo Molnar <mingo@redhat.com> Acked-by: Steven Rostedt <rostedt@goodmis.org> (previous version subtly different)
* Add HAVE_64BIT_ALIGNED_ACCESSJames Hogan2013-03-021-0/+16
| | | | | | | | | | | | | | | | | | | | | | On 64 bit architectures with no efficient unaligned access, padding and explicit alignment must be added in various places to prevent unaligned 64bit accesses (such as taskstats and trace ring buffer). However this also needs to apply to 32 bit architectures with 64 bit accesses requiring alignment such as metag. This is solved by adding a new Kconfig symbol HAVE_64BIT_ALIGNED_ACCESS which defaults to 64BIT && !HAVE_EFFICIENT_UNALIGNED_ACCESS, and can be explicitly selected by METAG and any other relevant architectures. This can be used in various places to determine whether 64bit alignment is required. Signed-off-by: James Hogan <james.hogan@imgtec.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Ingo Molnar <mingo@kernel.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Eric Paris <eparis@redhat.com> Cc: Will Drewry <wad@chromium.org>
* Revert some of "binfmt_elf: cleanups"James Hogan2013-03-021-0/+4
| | | | | | | | | | | | | | The commit "binfmt_elf: cleanups" (f670d0ecda73b7438eec9ed108680bc5f5362ad8) removed an ifndef elf_map but this breaks compilation for metag which does define elf_map. This adds the ifndef back in as it was before, but does not affect the other cleanups made by that patch. Signed-off-by: James Hogan <james.hogan@imgtec.com> Cc: Alexander Viro <viro@zeniv.linux.org.uk> Cc: linux-fsdevel@vger.kernel.org Acked-by: Mikael Pettersson <mikpe@it.uu.se>
* asm-generic/unistd.h: handle symbol prefixes in cond_syscallJames Hogan2013-03-021-1/+8
| | | | | | | | | | | Some architectures have symbol prefixes and set CONFIG_SYMBOL_PREFIX, but this wasn't taken into account by the generic cond_syscall. It's easy enough to fix in a generic fashion, so add the symbol prefix to symbol names in cond_syscall when CONFIG_SYMBOL_PREFIX is set. Signed-off-by: James Hogan <james.hogan@imgtec.com> Acked-by: Arnd Bergmann <arnd@arndb.de> Acked-by: Mike Frysinger <vapier@gentoo.org>
* asm-generic/io.h: check CONFIG_VIRT_TO_BUSJames Hogan2013-03-021-0/+2
| | | | | | | | | | Make asm-generic/io.h check CONFIG_VIRT_TO_BUS before defining virt_to_bus() and bus_to_virt(), otherwise it's easy to accidentally have a silently failing incorrect direct mapped definition rather then no definition at all. Signed-off-by: James Hogan <james.hogan@imgtec.com> Acked-by: Arnd Bergmann <arnd@arndb.de>
* Linux 3.8v3.8Linus Torvalds2013-02-181-1/+1
|
* Merge branch 'for-linus' of ↵Linus Torvalds2013-02-183-6/+18
|\ | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/dtor/input Pull input subsystem fixes from Dmitry Torokhov: "Two small driver fixups and a documentation update for managed input devices" * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/dtor/input: Input: wacom - fix wacom_set_report retry logic Input: document that unregistering managed devices is not necessary Input: lm8323 - fix checking PWM interrupt status
| * Input: wacom - fix wacom_set_report retry logicChris Bagwell2013-01-231-3/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Logic sets a value and then reads it back to make sure it worked and retries write on failures. Since read and write share a buffer, it needs to be set back up before writing though. Issue is not seen a lot because 1) it doesn't need to retry for a lot of tablets and 2) a lot of failures that need a retry are from an -ETIMEDOUT and hopefully buffer is not touched in this case. At least one user has shown logs with buffer being modified during -ETIMEDOUT case with linux 3.7 kernel. Signed-off-by: Chris Bagwell <chris@cnpbagwell.com> Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
| * Input: document that unregistering managed devices is not necessaryDmitry Torokhov2013-01-091-2/+14
| | | | | | | | | | | | | | | | | | | | Apparently some users of managed input devices are confused whether input_unregister_device() is needed when working with them. Clarify this in the kernel doc for devm_input_allocate_device(): in most cases there is no need to call neither input_unregister_device() nor input_free_device() when working with managed devices. Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
| * Input: lm8323 - fix checking PWM interrupt statusNickolai Zeldovich2013-01-061-1/+1
| | | | | | | | | | | | | | | | INT_PWM1 is already a bitmask, not the bit number, so shifting by INT_PWM1 is incorrect. Signed-off-by: Nickolai Zeldovich <nickolai@csail.mit.edu> Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
* | mm: fix pageblock bitmap allocationLinus Torvalds2013-02-181-6/+9
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Commit c060f943d092 ("mm: use aligned zone start for pfn_to_bitidx calculation") fixed out calculation of the index into the pageblock bitmap when a !SPARSEMEM zome was not aligned to pageblock_nr_pages. However, the _allocation_ of that bitmap had never taken this alignment requirement into accout, so depending on the exact size and alignment of the zone, the use of that index could then access past the allocation, resulting in some very subtle memory corruption. This was reported (and bisected) by Ingo Molnar: one of his random config builds would hang with certain very specific kernel command line options. In the meantime, commit c060f943d092 has been marked for stable, so this fix needs to be back-ported to the stable kernels that backported the commit to use the right alignment. Bisected-and-tested-by: Ingo Molnar <mingo@kernel.org> Acked-by: Mel Gorman <mgorman@suse.de> Cc: stable@kernel.org Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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