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2011-03-10arch/tile: support 4KB page size as well as 64KBChris Metcalf
The Tilera architecture traditionally supports 64KB page sizes to improve TLB utilization and improve performance when the hardware is being used primarily to run a single application. For more generic server scenarios, it can be beneficial to run with 4KB page sizes, so this commit allows that to be specified (by modifying the arch/tile/include/hv/pagesize.h header). As part of this change, we also re-worked the PTE management slightly so that PTE writes all go through a __set_pte() function where we can do some additional validation. The set_pte_order() function was eliminated since the "order" argument wasn't being used. One bug uncovered was in the PCI DMA code, which wasn't properly flushing the specified range. This was benign with 64KB pages, but with 4KB pages we were getting some larger flushes wrong. The per-cpu memory reservation code also needed updating to conform with the newer percpu stuff; before it always chose 64KB, and that was always correct, but with 4KB granularity we now have to pay closer attention and reserve the amount of memory that will be requested when the percpu code starts allocating. Signed-off-by: Chris Metcalf <cmetcalf@tilera.com>
2011-03-10arch/tile: add some more VMSPLIT options and use consistent namingChris Metcalf
This renames 3G_OPT to 2_75G, and adds 2_5G and 2_25G. For memory-intensive applications that are also network-buffer intensive it can be helpful to be able to tune the virtual address of the start of kernel memory. Signed-off-by: Chris Metcalf <cmetcalf@tilera.com>
2011-03-10arch/tile: fix some comments and whitespaceChris Metcalf
This is a grab bag of changes with no actual change to generated code. This includes whitespace and comment typos, plus a couple of stale comments being removed. Signed-off-by: Chris Metcalf <cmetcalf@tilera.com>
2011-03-01arch/tile: export some additional module symbolsChris Metcalf
This adds a grab bag of symbols that have been missing for various modules. Signed-off-by: Chris Metcalf <cmetcalf@tilera.com>
2011-03-01arch/tile: enhance existing finv_buffer_remote() routineChris Metcalf
It now takes an additional argument so it can be used to flush-and-invalidate pages that are cached using hash-for-home as well those that are cached with coherence point on a single cpu. This allows it to be used more widely for changing the coherence point of arbitrary pages when necessary. Signed-off-by: Chris Metcalf <cmetcalf@tilera.com>
2011-03-01arch/tile: fix two bugs in the backtracer codeChris Metcalf
The first is that we were using an incorrect hand-rolled variant of __kernel_text_address() which didn't handle module PCs. We now just use the standard API. The second was that we weren't accounting for the three-level page table when we were trying to pre-verify the addresses on the 64-bit TILE-Gx processor; we now do that correctly. Signed-off-by: Chris Metcalf <cmetcalf@tilera.com>
2011-03-01arch/tile: use extended assembly to inline __mb_incoherent()Chris Metcalf
This avoids having to maintain an additional separate assembly file, and of course the inline is slightly more efficient as well. Signed-off-by: Chris Metcalf <cmetcalf@tilera.com>
2011-03-01arch/tile: use a cleaner technique to enable interrupt for cpu_idle()Chris Metcalf
Previously we used iret to atomically return to kernel PL with interrupts enabled. However, it turns out that we are architecturally guaranteed that we can just set and clear the "interrupt critical section" and only interrupt on the following instruction, so we now do that instead, since it's cleaner. Signed-off-by: Chris Metcalf <cmetcalf@tilera.com>
2011-03-01arch/tile: sync up with <arch/sim.h> and <arch/sim_def.h> changesChris Metcalf
These headers are used by Linux but are maintained upstream. This change incorporates a few minor fixes to these headers, including a new sim_print() function, cleaner support for the sim_syscall() API, and a sim_query_cpu_speed() method. Signed-off-by: Chris Metcalf <cmetcalf@tilera.com>
2011-03-01arch/tile: fix reversed test of strict_strtol() return valueChris Metcalf
This fixes the "initfree" boot argument. Signed-off-by: Chris Metcalf <cmetcalf@tilera.com>
2011-03-01arch/tile: avoid a simulator warning during bootupChris Metcalf
As the added comment says, we can sometimes see a coherence warning from our simulator if the "swapper_pgprot" variable on the boot cpu has not been evicted from cache by the time the other cpus come up. Force it to be evicted so we never see the warning. Signed-off-by: Chris Metcalf <cmetcalf@tilera.com>
2011-03-01arch/tile: export <asm/hardwall.h> to userspaceChris Metcalf
This should have been as part of the initial hardwall submission to LKML but was overlooked. The header provides the ioctl definitions for manipulating the hardwall fd, so needs to be available to userspace. Signed-off-by: Chris Metcalf <cmetcalf@tilera.com>
2011-03-01arch/tile: warn and retry if an IPI is not accepted by the target cpuChris Metcalf
Previously we assumed this was impossible, but in fact it can happen. Handle it gracefully by retrying after issuing a warning. Signed-off-by: Chris Metcalf <cmetcalf@tilera.com>
2011-03-01arch/tile: stop disabling INTCTRL_1 interrupts during hypervisor downcallsChris Metcalf
The problem was that this could lead to IPIs being disabled during the softirq processing after a hypervisor downcall (e.g. for I/O), since both IPI and device interrupts use the INCTRL_1 downcall mechanism. When this happened at the wrong time, it could lead to deadlock. Luckily, we were already maintaining the per-interrupt state we need, and using it in the proper way in the hypervisor, so all we had to do was to change Linux to stop blocking downcall interrupts for the entire length of the downcall. (Now they're blocked while we're executing the downcall routine itself, but not while we're executing any subsequent softirq routines.) The hypervisor is doing a very small amount of work it no longer needs to do (masking INTCTRL_1 on entry to the client interrupt routine), but doing so means that older versions of Tile Linux will continue to work with a current hypervisor, so that seems reasonable. Signed-off-by: Chris Metcalf <cmetcalf@tilera.com>
2011-03-01arch/tile: fix __ndelay etc to work betterChris Metcalf
The current implementations of __ndelay and __udelay call a hypervisor service to delay, but the hypervisor service isn't actually implemented very well, and the consensus is that Linux should handle figuring this out natively and not use a hypervisor service. By converting nanoseconds to cycles, and then spinning until the cycle counter reaches the desired cycle, we get several benefits: first, we are sensitive to the actual clock speed; second, we use less power by issuing a slow SPR read once every six cycles while we delay; and third, we properly handle the case of an interrupt by exiting at the target time rather than after some number of cycles. Signed-off-by: Chris Metcalf <cmetcalf@tilera.com>
2011-03-01arch/tile: bug fix: exec'ed task thought it was still single-steppingChris Metcalf
To handle single-step, tile mmap's a page of memory in the process space for each thread and uses it to construct a version of the instruction that we want to single step. If the process exec's, though, we lose that mapping, and the kernel needs to be aware that it will need to recreate it if the exec'ed process than tries to single-step as well. Also correct some int32_t to s32 for better kernel style. Signed-off-by: Chris Metcalf <cmetcalf@tilera.com>
2011-03-01arch/tile: catch up with section naming convention in 2.6.35Chris Metcalf
The convention changed to, e.g., ".data..page_aligned". This commit fixes the places in the tile architecture that were still using the old convention. One tile-specific section (.init.page) was dropped in favor of just using an "aligned" attribute. Sam Ravnborg <sam@ravnborg.org> pointed out __PAGE_ALIGNED_BSS, etc. Signed-off-by: Chris Metcalf <cmetcalf@tilera.com>
2011-02-25arch/tile: Fix atomic_read() definition to use ACCESS_ONCEChris Metcalf
This adds the volatile cast which forces the compiler to emit the load. Suggested by Peter Zijlstra <peterz@infradead.org>. Signed-off-by: Chris Metcalf <cmetcalf@tilera.com>
2011-02-23tile: Select GENERIC_HARDIRQS_NO_DEPRECATEDThomas Gleixner
irq chip converted and proper accessor functions used. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Chris Metcalf <cmetcalf@tilera.com>
2011-02-23tile: Use proper accessor functions in show_interrupt()Thomas Gleixner
Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Chris Metcalf <cmetcalf@tilera.com>
2011-02-23tile: Convert irq_chip to new functionsThomas Gleixner
Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Chris Metcalf <cmetcalf@tilera.com>
2011-02-23tile: Fix __pte_free_tlbPeter Zijlstra
Tile's __pte_free_tlb() implementation makes assumptions about the generic mmu_gather implementation, cure this ;-) Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Chris Metcalf <cmetcalf@tilera.com>
2011-01-21tile: Use generic irq KconfigThomas Gleixner
No functional change. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: Chris Metcalf <cmetcalf@tilera.com>
2011-01-21genirq: Remove __do_IRQThomas Gleixner
All architectures are finally converted. Remove the cruft. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: Richard Henderson <rth@twiddle.net> Cc: Mike Frysinger <vapier@gentoo.org> Cc: David Howells <dhowells@redhat.com> Cc: Tony Luck <tony.luck@intel.com> Cc: Greg Ungerer <gerg@uclinux.org> Cc: Michal Simek <monstr@monstr.eu> Acked-by: David Howells <dhowells@redhat.com> Cc: Kyle McMartin <kyle@mcmartin.ca> Acked-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Chen Liqin <liqin.chen@sunplusct.com> Cc: "David S. Miller" <davem@davemloft.net> Cc: Chris Metcalf <cmetcalf@tilera.com> Cc: Jeff Dike <jdike@addtoit.com>
2011-01-20kconfig: rename CONFIG_EMBEDDED to CONFIG_EXPERTDavid Rientjes
The meaning of CONFIG_EMBEDDED has long since been obsoleted; the option is used to configure any non-standard kernel with a much larger scope than only small devices. This patch renames the option to CONFIG_EXPERT in init/Kconfig and fixes references to the option throughout the kernel. A new CONFIG_EMBEDDED option is added that automatically selects CONFIG_EXPERT when enabled and can be used in the future to isolate options that should only be considered for embedded systems (RISC architectures, SLOB, etc). Calling the option "EXPERT" more accurately represents its intention: only expert users who understand the impact of the configuration changes they are making should enable it. Reviewed-by: Ingo Molnar <mingo@elte.hu> Acked-by: David Woodhouse <david.woodhouse@intel.com> Signed-off-by: David Rientjes <rientjes@google.com> Cc: Greg KH <gregkh@suse.de> Cc: "David S. Miller" <davem@davemloft.net> Cc: Jens Axboe <axboe@kernel.dk> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Robin Holt <holt@sgi.com> Cc: <linux-arch@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-12-17arch/tile: handle rt_sigreturn() more cleanlyChris Metcalf
The current tile rt_sigreturn() syscall pattern uses the common idiom of loading up pt_regs with all the saved registers from the time of the signal, then anticipating the fact that we will clobber the ABI "return value" register (r0) as we return from the syscall by setting the rt_sigreturn return value to whatever random value was in the pt_regs for r0. However, this breaks in our 64-bit kernel when running "compat" tasks, since we always sign-extend the "return value" register to properly handle returned pointers that are in the upper 2GB of the 32-bit compat address space. Doing this to the sigreturn path then causes occasional random corruption of the 64-bit r0 register. Instead, we stop doing the crazy "load the return-value register" hack in sigreturn. We already have some sigreturn-specific assembly code that we use to pass the pt_regs pointer to C code. We extend that code to also set the link register to point to a spot a few instructions after the usual syscall return address so we don't clobber the saved r0. Now it no longer matters what the rt_sigreturn syscall returns, and the pt_regs structure can be cleanly and completely reloaded. Signed-off-by: Chris Metcalf <cmetcalf@tilera.com>
2010-12-17arch/tile: handle CLONE_SETTLS in copy_thread(), not user spaceChris Metcalf
Previously we were just setting up the "tp" register in the new task as started by clone() in libc. However, this is not quite right, since in principle a signal might be delivered to the new task before it had its TLS set up. (Of course, this race window still exists for resetting the libc getpid() cached value in the new task, in principle. But in any case, we are now doing this exactly the way all other architectures do it.) This change is important for 2.6.37 since the tile glibc we will be submitting upstream will not set TLS in user space any more, so it will only work on a kernel that has this fix. It should also be taken for 2.6.36.x in the stable tree if possible. Signed-off-by: Chris Metcalf <cmetcalf@tilera.com> Cc: stable <stable@kernel.org>
2010-11-25Merge git://git.kernel.org/pub/scm/linux/kernel/git/cmetcalf/linux-tileLinus Torvalds
* git://git.kernel.org/pub/scm/linux/kernel/git/cmetcalf/linux-tile: arch/tile: fix memchr() not to dereference memory for zero length arch/tile: make glibc's sysconf(_SC_NPROCESSORS_CONF) work correctly arch/tile: fix rwlock so would-be write lockers don't block new readers
2010-11-25Merge branch 'drivers' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/cmetcalf/linux-tile * 'drivers' of git://git.kernel.org/pub/scm/linux/kernel/git/cmetcalf/linux-tile: pci root complex: support for tile architecture drivers/net/tile/: on-chip network drivers for the tile architecture MAINTAINERS: add drivers/char/hvc_tile.c as maintained by tile
2010-11-24arch/tile: fix memchr() not to dereference memory for zero lengthChris Metcalf
This change fixes a bug that memchr() will read the first word of the source even if the length is zero. Ironically, the code was originally written with a test to avoid exactly this problem, but to make the code conform to Linux coding standards with all declarations preceding all statements, the first load from memory was moved up above that test as the initial value for a variable. The change just moves all the variable declarations to the top of the file, with no initializers, so that the test can also be at the top of the file. Signed-off-by: Chris Metcalf <cmetcalf@tilera.com>
2010-11-24arch/tile: make glibc's sysconf(_SC_NPROCESSORS_CONF) work correctlyChris Metcalf
glibc assumes that it can count /sys/devices/system/cpu/cpu* to get the number of configured cpus. For this to be valid on tile, we need to generate a "cpu" entry for all cpus, including the ones that are not currently allocated for Linux's use. Signed-off-by: Chris Metcalf <cmetcalf@tilera.com>
2010-11-24Merge branch 'master' into for-linusChris Metcalf
2010-11-24pci root complex: support for tile architectureChris Metcalf
This change enables PCI root complex support for TILEPro. Unlike TILE-Gx, TILEPro has no support for memory-mapped I/O, so the PCI support consists of hypervisor upcalls for PIO, DMA, etc. However, the performance is fine for the devices we have tested with so far (1Gb Ethernet, SATA, etc.). The <asm/io.h> header was tweaked to be a little bit more aggressive about disabling attempts to map/unmap IO port space. The hacky <asm/pci-bridge.h> header was rolled into the <asm/pci.h> header and the result was simplified. Both of the latter two headers were preliminary versions not meant for release before now - oh well. There is one quirk for our TILEmpower platform, which accidentally negotiates up to 5GT and needs to be kicked down to 2.5GT. Signed-off-by: Chris Metcalf <cmetcalf@tilera.com>
2010-11-24drivers/net/tile/: on-chip network drivers for the tile architectureChris Metcalf
This change adds the first network driver for the tile architecture, supporting the on-chip XGBE and GBE shims. The infrastructure is present for the TILE-Gx networking drivers (another three source files in the new directory) but for now the the actual tilegx sources are waiting on releasing hardware to initial customers. Note that arch/tile/include/hv/* are "upstream" headers from the Tilera hypervisor and will probably benefit less from LKML review. Signed-off-by: Chris Metcalf <cmetcalf@tilera.com>
2010-11-17BKL: remove extraneous #include <smp_lock.h>Arnd Bergmann
The big kernel lock has been removed from all these files at some point, leaving only the #include. Remove this too as a cleanup. Signed-off-by: Arnd Bergmann <arnd@arndb.de> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-11-15arch/tile: fix rwlock so would-be write lockers don't block new readersChris Metcalf
This avoids a deadlock in the IGMP code where one core gets a read lock, another core starts trying to get a write lock (thus blocking new readers), and then the first core tries to recursively re-acquire the read lock. We still try to preserve some degree of balance by giving priority to additional write lockers that come along while the lock is held for write, so they can all complete quickly and return the lock to the readers. Signed-off-by: Chris Metcalf <cmetcalf@tilera.com>
2010-11-01arch/tile: mark "hardwall" device as non-seekableChris Metcalf
Arnd's recent patch series tagged this device with noop_llseek, conservatively. In fact, it should be no_llseek, which we arrange for by opening the device with nonseekable_open(). Signed-off-by: Chris Metcalf <cmetcalf@tilera.com>
2010-11-01asm-generic/stat.h: support 64-bit file time_t for stat()Chris Metcalf
The existing asm-generic/stat.h specifies st_mtime, etc., as a 32-value, and works well for 32-bit architectures (currently microblaze, score, and 32-bit tile). However, for 64-bit architectures it isn't sufficient to return 32 bits of time_t; this isn't good insurance against the 2037 rollover. (It also makes glibc support less convenient, since we can't use glibc's handy STAT_IS_KERNEL_STAT mode.) This change extends the two "timespec" fields for each of the three atime, mtime, and ctime fields from "int" to "long". As a result, on 32-bit platforms nothing changes, and 64-bit platforms will now work as expected. The only wrinkle is 32-bit userspace under 64-bit kernels taking advantage of COMPAT mode. For these, we leave the "struct stat64" definitions with the "int" versions of the time_t and nsec fields, so that architectures can implement compat_sys_stat64() and friends with sys_stat64(), etc., and get the expected 32-bit structure layout. This requires a field-by-field copy in the kernel, implemented by the code guarded under __ARCH_WANT_STAT64. This does mean that the shape of the "struct stat" and "struct stat64" structures is different on a 64-bit kernel, but only one of the two structures should ever be used by any given process: "struct stat" is meant for 64-bit userspace only, and "struct stat64" for 32-bit userspace only. (On a 32-bit kernel the two structures continue to have the same shape, since "long" is 32 bits.) The alternative is keeping the two structures the same shape on 64-bit kernels, which means a 64-bit time_t in "struct stat64" for 32-bit processes. This is a little unnatural since 32-bit userspace can't do anything with 64 bits of time_t information, since time_t is just "long", not "int64_t"; and in any case 32-bit userspace might expect to be running under a 32-bit kernel, which can't provide the high 32 bits anyway. In the case of a 32-bit kernel we'd then be extending the kernel's 32-bit time_t to 64 bits, then truncating it back to 32 bits again in userspace, for no particular reason. And, as mentioned above, if we have 64-bit time_t for 32-bit processes we can't easily use glibc's STAT_IS_KERNEL_STAT, since glibc's stat structure requires an embedded "struct timespec", which is a pair of "long" (32-bit) values in a 32-bit userspace. "Inventive" solutions are possible, but are pretty hacky. Signed-off-by: Chris Metcalf <cmetcalf@tilera.com> Acked-by: Arnd Bergmann <arnd@arndb.de>
2010-11-01arch/tile: don't allow user code to set the PL via ptrace or signal returnChris Metcalf
The kernel was allowing any component of the pt_regs to be updated either by signal handlers writing to the stack, or by processes writing via PTRACE_POKEUSR or PTRACE_SETREGS, which meant they could set their PL up from 0 to 1 and get access to kernel code and data (or, in practice, cause a kernel panic). We now always reset the ex1 field, allowing the user to set their ICS bit only. Signed-off-by: Chris Metcalf <cmetcalf@tilera.com>
2010-11-01arch/tile: correct double syscall restart for nested signalsChris Metcalf
This change is modelled on similar fixes for other architectures. The pt_regs "faultnum" member is set to the trap (fault) number that caused us to enter the kernel, and is INT_SWINT_1 for the syscall software interrupt. We already supported a pseudo value, INT_SWINT_1_SIGRETURN, that we used for the rt_sigreturn syscall; it avoided the case where one signal was handled, then we "tail-called" to another handler. This change avoids the similar case where we start to call one handler, then are preempted into another handler when we start trying to run the first handler. We clear ->faultnum after calling handle_signal(), and to be paranoid also in the case where there was no signal to deliver. Signed-off-by: Chris Metcalf <cmetcalf@tilera.com>
2010-11-01arch/tile: avoid __must_check warning on one strict_strtol checkChris Metcalf
For the "initfree" boot argument it's not that big a deal, but to avoid warnings in the code, we check for a valid value before allowing the specified argument to override the kernel default. Signed-off-by: Chris Metcalf <cmetcalf@tilera.com>
2010-11-01arch/tile: bomb raw_local_irq_ to arch_local_irq_Chris Metcalf
This completes the tile migration to the new naming scheme for the architecture-specific irq management code. Signed-off-by: Chris Metcalf <cmetcalf@tilera.com>
2010-11-01arch/tile: complete migration to new kmap_atomic schemeChris Metcalf
This change makes KM_TYPE_NR independent of the actual deprecated list of km_type values, which are no longer used in tile code anywhere. For now we leave it set to 8, allowing that many nested mappings, and thus reserving 32MB of address space. A few remaining places using KM_* values were cleaned up as well. Signed-off-by: Chris Metcalf <cmetcalf@tilera.com>
2010-10-28Merge branch 'kconfig' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/mmarek/kbuild-2.6 * 'kconfig' of git://git.kernel.org/pub/scm/linux/kernel/git/mmarek/kbuild-2.6: (38 commits) kbuild: convert `arch/tile' to the kconfig mainmenu upgrade README: cite nconfig Revert "kconfig: Temporarily disable dependency warnings" kconfig: Use PATH_MAX instead of 128 for path buffer sizes. kconfig: Fix realloc usage() kconfig: Propagate const kconfig: Don't go out from read config loop when you read new symbol kconfig: fix menuconfig on debian lenny kbuild: migrate all arch to the kconfig mainmenu upgrade kconfig: expand file names kconfig: use the file's name of sourced file kconfig: constify file name kconfig: don't emit warning upon rootmenu's prompt redefinition kconfig: replace KERNELVERSION usage by the mainmenu's prompt kconfig: delay gconf window initialization kconfig: expand by default the rootmenu's prompt kconfig: add a symbol string expansion helper kconfig: regen parser kconfig: implement the `mainmenu' directive kconfig: allow PACKAGE to be defined on the compiler's command-line ... Fix up trivial conflict in arch/mn10300/Kconfig
2010-10-28kbuild: convert `arch/tile' to the kconfig mainmenu upgradeArnaud Lacombe
Signed-off-by: Arnaud Lacombe <lacombar@gmail.com> Signed-off-by: Michal Marek <mmarek@suse.cz>
2010-10-27Remove duplicate includes from many filesZimny Lech
Signed-off-by: Zimny Lech <napohybelskurwysynom2010@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-10-27ptrace: cleanup arch_ptrace() on tileNamhyung Kim
Remove checking @addr less than 0 because @addr is now unsigned. Signed-off-by: Namhyung Kim <namhyung@gmail.com> Acked-by: Chris Metcalf <cmetcalf@tilera.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-10-27ptrace: change signature of arch_ptrace()Namhyung Kim
Fix up the arguments to arch_ptrace() to take account of the fact that @addr and @data are now unsigned long rather than long as of a preceding patch in this series. Signed-off-by: Namhyung Kim <namhyung@gmail.com> Cc: <linux-arch@vger.kernel.org> Acked-by: Roland McGrath <roland@redhat.com> Acked-by: David Howells <dhowells@redhat.com> Acked-by: Geert Uytterhoeven <geert@linux-m68k.org> Acked-by: David S. Miller <davem@davemloft.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-10-27tile: enable ARCH_DMA_ADDR_T_64BITFUJITA Tomonori
Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp> Acked-by: Chris Metcalf <cmetcalf@tilera.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-10-27mm: fix race in kunmap_atomic()Peter Zijlstra
Christoph reported a nice splat which illustrated a race in the new stack based kmap_atomic implementation. The problem is that we pop our stack slot before we're completely done resetting its state -- in particular clearing the PTE (sometimes that's CONFIG_DEBUG_HIGHMEM). If an interrupt happens before we actually clear the PTE used for the last slot, that interrupt can reuse the slot in a dirty state, which triggers a BUG in kmap_atomic(). Fix this by introducing kmap_atomic_idx() which reports the current slot index without actually releasing it and use that to find the PTE and delay the _pop() until after we're completely done. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Reported-by: Christoph Hellwig <hch@infradead.org> Acked-by: Rik van Riel <riel@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>