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* [MIPS] Fix sparsemem support.Chad Reese2006-06-062-0/+16
| | | | | | | | | | | | Move memory_present() in arch/mips/kernel/setup.c. When using sparsemem extreme, this function does an allocate for bootmem. This would always fail since init_bootmem hasn't been called yet. Move memory_present after free_bootmem. This only marks actual memory ranges as present instead of the entire address space. Signed-off-by: Chad Reese <creese@caviumnetworks.com> Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
* [MIPS] Fix 64-bit build for RM7000.Ralf Baechle2006-06-061-0/+1
| | | | | | RM7000 has 40-bit virtual / 36-bit physical address space. Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
* [MIPS] Fix non-linear memory mapping on MIPSSergei Shtylyov2006-06-062-27/+31
| | | | | | | | | | | Fix the non-linear memory mapping done via remap_file_pages() -- it didn't work on any MIPS CPU because the page offset clashing with _PAGE_FILE and some other page protection bits which should have been left zeros for this kind of pages. Signed-off-by: Konstantin Baydarov <kbaidarov@ru.mvista.com> Signed-off-by: Sergei Shtylyov <sshtylyov@ru.mvista.com> Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
* [MIPS] Fix swap entry for MIPS32 36-bit physical addressSergei Shtylyov2006-06-061-2/+14
| | | | | | | | | | | With 64-bit physical address enabled, 'swapon' was causing kernel oops on Alchemy CPUs (MIPS32) because of the swap entry type field corrupting the _PAGE_FILE bit in 'pte_low' field. So, switch to storing the swap entry in 'pte_high' field using all its bits except _PAGE_GLOBAL and _PAGE_VALID which gives 25 bits for the swap entry offset. Signed-off-by: Sergei Shtylyov <sshtylyov@ru.mvista.com> Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
* [MIPS] Fix mprotect() syscall for MIPS32 w/36-bit physical address supportSergei Shtylyov2006-06-061-2/+3
| | | | | | | | | Fix mprotect() syscall for MIPS32 CPUs with 36-bit physical address support: pte_modify() macro didn't clear the hardware page protection bits before modifying... Signed-off-by: Sergei Shtylyov <sshtylyov@ru.mvista.com> Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
* [MIPS] Fix declaration of smp_prepare_cpus() platform hook.Ralf Baechle2006-06-061-2/+2
| | | | | | | A while ago prom_prepare_cpus was replaced by plat_prepare_cpus but the declaration has stayed unchanged. Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
* [MIPS] Fix instable BogoMIPS on multi-issue processors.Ralf Baechle2006-06-061-10/+12
| | | | | | | Increase alignment of BogoMIPS loop to 8 bytes. Having the delay loop overlap cache line boundaries may cause instable delays. Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
* [MIPS] Remove duplicate declaration of cpu_online_map.Ralf Baechle2006-06-061-1/+0
| | | | Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
* Merge master.kernel.org:/pub/scm/linux/kernel/git/davem/sparc-2.6Linus Torvalds2006-06-021-1/+9
|\ | | | | | | | | | | * master.kernel.org:/pub/scm/linux/kernel/git/davem/sparc-2.6: [SPARC64]: Fix D-cache corruption in mremap [SPARC64]: Make smp_processor_id() functional before start_kernel()
| * [SPARC64]: Fix D-cache corruption in mremapDavid S. Miller2006-06-011-1/+9
| | | | | | | | | | | | | | | | | | | | | | | | If we move a mapping from one virtual address to another, and this changes the virtual color of the mapping to those pages, we can see corrupt data due to D-cache aliasing. Check for and deal with this by overriding the move_pte() macro. Set things up so that other platforms can cleanly override the move_pte() macro too. Signed-off-by: David S. Miller <davem@davemloft.net>
* | [MIPS] Treat R14000 like R10000.Kumba2006-06-011-1/+3
| | | | | | | | | | Signed-off-by: Joshua Kinard <kumba@gentoo.org> Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
* | [MIPS] Update/Fix instruction definitionsThiemo Seufer2006-06-011-5/+28
| | | | | | | | | | | | | | | | A small bugfix for up to now unused instruction definitions, and a somewhat larger update to cover MIPS32R2 instructions. Signed-off-by: Thiemo Seufer <ths@networkno.de> Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
* | [MIPS] DSP and MDMX share the same config flag bit.Thiemo Seufer2006-06-011-1/+1
| | | | | | | | | | | | | | Clarify comment. Signed-off-by: Thiemo Seufer <ths@networkno.de> Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
* | [MIPS] Update struct sigcontext member namesDaniel Jacobowitz2006-06-011-2/+8
| | | | | | | | | | | | | | | | Rename the 64-bit sc_hi and sc_lo arrays to use the same names as the 32-bit struct sigcontext (sc_mdhi, sc_hi1, et cetera). Signed-off-by: Daniel Jacobowitz <dan@codesourcery.com> Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
* | [MIPS] Update/fix futex assemblyRalf Baechle2006-06-011-25/+116
| | | | | | | | | | | | | | | | | | o Implement futex_atomic_op_inuser() operation o Don't use the R10000-ll/sc bug workaround version for every processor. branch likely is deprecated and some historic ll/sc processors don't implement it. In any case it's slow. Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
* | [MIPS] Fix detection and handling of the 74K processor.Chris Dearman2006-06-011-1/+3
| | | | | | | | | | | | | | | | Nothing exciting; Linux just didn't know it yet so this is most adding a value to a case statement. Signed-off-by: Chris Dearman <chris@mips.com> Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
* | [MIPS] Fix marking buddy of pte global for MIPS32 w/36-bit physical addressSergei Shtylyov2006-06-011-39/+49
|/ | | | | | | | | | | | | | | | | | In case of CONFIG_64BIT_PHYS_ADDR, set_pte() and pte_clear() functions only set _PAGE_GLOBAL bit in the pte_low field of the buddy PTEs, forgetting to propagate ito to pte_high. Thus, the both pages might not really be made global for the CPU (since it AND's the G-bit of the odd / even PTEs together to decide whether they're global or not). Thus, if only a single page is allocated via vmalloc() or ioremap(), it's not really global for CPU (and it must be, since this is kernel mapping), and thus its ASID is compared against the current process' one -- so, we'll get into trouble sooner or later... Also, pte_none() will fail on global pages because _PAGE_GLOBAL bit is set in both pte_low and pte_high, and pte_val() will return u64 value consisting of those fields concateneted. Signed-off-by: Sergei Shtylyov <sshtylyov@ru.mvista.com> Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
* [MIPS] 24K LV: Add core card id.Chris Dearman2006-04-271-0/+1
| | | | Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
* [MIPS] Fix bitops for MIPS32/MIPS64 CPUs.Atsushi Nemoto2006-04-271-32/+24
| | | | | | | | | | With recent rewrite for generic bitops, fls() for 32bit kernel with MIPS64_CPU is broken. Also, ffs(), fls() should be defined the same way as the libc and compiler built-in routines (returns int instead of unsigned long). Signed-off-by: Atsushi Nemoto <anemo@mba.ocn.ne.jp> Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
* [MIPS] Handle IDE PIO cache aliases on SMP.Ralf Baechle2006-04-192-2/+45
| | | | Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
* [MIPS] MIPS boards: Set HZ to 100.Ralf Baechle2006-04-191-0/+13
| | | | | | | 1000Hz will bring an FPGA CPU down on it's knees and it's even worse on multithreaded cores. Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
* [MIPS] FPU affinity for MT ASE.Ralf Baechle2006-04-194-1/+53
| | | | Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
* [MIPS] MT: Improved multithreading support.Ralf Baechle2006-04-1916-21/+924
| | | | Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
* [MIPS] kpsd and other AP/SP improvements.Ralf Baechle2006-04-194-14/+102
| | | | Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
* [MIPS] Fix genrtc compilation.Ralf Baechle2006-04-191-2/+2
| | | | | Signed-off-by: Ralf Roesch <ralf.roesch@rw-gmbh.de> Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
* [MIPS] Use "R" constraint for cache_op.Ralf Baechle2006-04-191-1/+1
| | | | | | | Gcc might emit an absolute address for the the "m" constraint which gas unfortunately does not permit. Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
* [MIPS] Fix the crime against humanity that mipsIRQ.S is.Ralf Baechle2006-04-192-20/+17
| | | | Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
* [MIPS] JMR3927 build fixes for the RTC code.Ralf Baechle2006-04-192-2/+15
| | | | Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
* [MIPS] MV6434x: Add prototype of interrupt dispatch function.Ralf Baechle2006-04-191-0/+2
| | | | Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
* [MIPS] it8172: Fix build of serial driver.Ralf Baechle2006-04-191-6/+6
| | | | Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
* [MIPS] Rewrite spurious_interrupt from assembler to C.Ralf Baechle2006-04-191-0/+1
| | | | Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
* [MIPS] Wire up sync_file_range(2).Ralf Baechle2006-04-191-6/+9
| | | | Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
* [MIPS] Wire splice syscall.Ralf Baechle2006-04-191-6/+9
| | | | Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
* [MIPS] More SHT_* and SHF_* ELF definitions.Ralf Baechle2006-04-191-2/+43
| | | | Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
* [MIPS] Fix vectored interrupt support in TLB exception handler generator.Ralf Baechle2006-04-191-0/+1
| | | | Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
* [MIPS] Provide access functions for c0_badvaddr.Ralf Baechle2006-04-191-0/+3
| | | | Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
* [MIPS] Make set_vi_srs_handler static.Ralf Baechle2006-04-191-1/+0
| | | | Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
* [PATCH] Configurable NODES_SHIFTYasunori Goto2006-04-111-7/+0
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Current implementations define NODES_SHIFT in include/asm-xxx/numnodes.h for each arch. Its definition is sometimes configurable. Indeed, ia64 defines 5 NODES_SHIFT values in the current git tree. But it looks a bit messy. SGI-SN2(ia64) system requires 1024 nodes, and the number of nodes already has been changeable by config. Suitable node's number may be changed in the future even if it is other architecture. So, I wrote configurable node's number. This patch set defines just default value for each arch which needs multi nodes except ia64. But, it is easy to change to configurable if necessary. On ia64 the number of nodes can be already configured in generic ia64 and SN2 config. But, NODES_SHIFT is defined for DIG64 and HP'S machine too. So, I changed it so that all platforms can be configured via CONFIG_NODES_SHIFT. It would be simpler. See also: http://marc.theaimsgroup.com/?l=linux-kernel&m=114358010523896&w=2 Signed-off-by: Yasunori Goto <y-goto@jp.fujitsu.com> Cc: Hirokazu Takata <takata@linux-m32r.org> Cc: "Luck, Tony" <tony.luck@intel.com> Cc: Andi Kleen <ak@muc.de> Cc: Paul Mackerras <paulus@samba.org> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru> Cc: Richard Henderson <rth@twiddle.net> Cc: Kyle McMartin <kyle@mcmartin.ca> Cc: Russell King <rmk@arm.linux.org.uk> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Jack Steiner <steiner@sgi.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* Merge master.kernel.org:/home/rmk/linux-2.6-serialLinus Torvalds2006-03-281-84/+1
|\ | | | | | | | | | | | | | | * master.kernel.org:/home/rmk/linux-2.6-serial: [SERIAL] Provide Cirrus EP93xx AMBA PL010 serial support. [SERIAL] amba-pl010: allow platforms to specify modem control method [SERIAL] Remove obsoleted au1x00_uart driver [SERIAL] Small time UART configuration fix for AU1100 processor
| * [SERIAL] Remove obsoleted au1x00_uart driverRalf Baechle2006-03-261-84/+1
| | | | | | | | | | | | | | As announced in feature-removal-schedule.txt. Signed-off-by: Ralf Baechle <ralf@linux-mips.org> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
* | [PATCH] RTC: Remove RTC UIP synchronization on MIPS MC146818Matt Mackall2006-03-281-31/+2
| | | | | | | | | | | | | | | | Signed-off-by: Matt Mackall <mpm@selenic.com> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Alessandro Zummo <a.zummo@towertech.it> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* | [PATCH] mips: fixed collision of rtc function nameYoichi Yuasa2006-03-271-6/+6
| | | | | | | | | | | | | | | | | | | | Fix the collision of rtc function name. Signed-off-by: Yoichi Yuasa <yoichi_yuasa@tripeaks.co.jp> Cc: Alessandro Zummo <a.zummo@towertech.it> Cc: Ralf Baechle <ralf@linux-mips.org> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* | [PATCH] lightweight robust futexes updatesIngo Molnar2006-03-271-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | - fix: initialize the robust list(s) to NULL in copy_process. - doc update - cleanup: rename _inuser to _inatomic - __user cleanups and other small cleanups Signed-off-by: Ingo Molnar <mingo@elte.hu> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Arjan van de Ven <arjan@infradead.org> Cc: Ulrich Drepper <drepper@redhat.com> Cc: Andi Kleen <ak@muc.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* | [PATCH] lightweight robust futexes: arch defaultsIngo Molnar2006-03-271-0/+6
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This patchset provides a new (written from scratch) implementation of robust futexes, called "lightweight robust futexes". We believe this new implementation is faster and simpler than the vma-based robust futex solutions presented before, and we'd like this patchset to be adopted in the upstream kernel. This is version 1 of the patchset. Background ---------- What are robust futexes? To answer that, we first need to understand what futexes are: normal futexes are special types of locks that in the noncontended case can be acquired/released from userspace without having to enter the kernel. A futex is in essence a user-space address, e.g. a 32-bit lock variable field. If userspace notices contention (the lock is already owned and someone else wants to grab it too) then the lock is marked with a value that says "there's a waiter pending", and the sys_futex(FUTEX_WAIT) syscall is used to wait for the other guy to release it. The kernel creates a 'futex queue' internally, so that it can later on match up the waiter with the waker - without them having to know about each other. When the owner thread releases the futex, it notices (via the variable value) that there were waiter(s) pending, and does the sys_futex(FUTEX_WAKE) syscall to wake them up. Once all waiters have taken and released the lock, the futex is again back to 'uncontended' state, and there's no in-kernel state associated with it. The kernel completely forgets that there ever was a futex at that address. This method makes futexes very lightweight and scalable. "Robustness" is about dealing with crashes while holding a lock: if a process exits prematurely while holding a pthread_mutex_t lock that is also shared with some other process (e.g. yum segfaults while holding a pthread_mutex_t, or yum is kill -9-ed), then waiters for that lock need to be notified that the last owner of the lock exited in some irregular way. To solve such types of problems, "robust mutex" userspace APIs were created: pthread_mutex_lock() returns an error value if the owner exits prematurely - and the new owner can decide whether the data protected by the lock can be recovered safely. There is a big conceptual problem with futex based mutexes though: it is the kernel that destroys the owner task (e.g. due to a SEGFAULT), but the kernel cannot help with the cleanup: if there is no 'futex queue' (and in most cases there is none, futexes being fast lightweight locks) then the kernel has no information to clean up after the held lock! Userspace has no chance to clean up after the lock either - userspace is the one that crashes, so it has no opportunity to clean up. Catch-22. In practice, when e.g. yum is kill -9-ed (or segfaults), a system reboot is needed to release that futex based lock. This is one of the leading bugreports against yum. To solve this problem, 'Robust Futex' patches were created and presented on lkml: the one written by Todd Kneisel and David Singleton is the most advanced at the moment. These patches all tried to extend the futex abstraction by registering futex-based locks in the kernel - and thus give the kernel a chance to clean up. E.g. in David Singleton's robust-futex-6.patch, there are 3 new syscall variants to sys_futex(): FUTEX_REGISTER, FUTEX_DEREGISTER and FUTEX_RECOVER. The kernel attaches such robust futexes to vmas (via vma->vm_file->f_mapping->robust_head), and at do_exit() time, all vmas are searched to see whether they have a robust_head set. Lots of work went into the vma-based robust-futex patch, and recently it has improved significantly, but unfortunately it still has two fundamental problems left: - they have quite complex locking and race scenarios. The vma-based patches had been pending for years, but they are still not completely reliable. - they have to scan _every_ vma at sys_exit() time, per thread! The second disadvantage is a real killer: pthread_exit() takes around 1 microsecond on Linux, but with thousands (or tens of thousands) of vmas every pthread_exit() takes a millisecond or more, also totally destroying the CPU's L1 and L2 caches! This is very much noticeable even for normal process sys_exit_group() calls: the kernel has to do the vma scanning unconditionally! (this is because the kernel has no knowledge about how many robust futexes there are to be cleaned up, because a robust futex might have been registered in another task, and the futex variable might have been simply mmap()-ed into this process's address space). This huge overhead forced the creation of CONFIG_FUTEX_ROBUST, but worse than that: the overhead makes robust futexes impractical for any type of generic Linux distribution. So it became clear to us, something had to be done. Last week, when Thomas Gleixner tried to fix up the vma-based robust futex patch in the -rt tree, he found a handful of new races and we were talking about it and were analyzing the situation. At that point a fundamentally different solution occured to me. This patchset (written in the past couple of days) implements that new solution. Be warned though - the patchset does things we normally dont do in Linux, so some might find the approach disturbing. Parental advice recommended ;-) New approach to robust futexes ------------------------------ At the heart of this new approach there is a per-thread private list of robust locks that userspace is holding (maintained by glibc) - which userspace list is registered with the kernel via a new syscall [this registration happens at most once per thread lifetime]. At do_exit() time, the kernel checks this user-space list: are there any robust futex locks to be cleaned up? In the common case, at do_exit() time, there is no list registered, so the cost of robust futexes is just a simple current->robust_list != NULL comparison. If the thread has registered a list, then normally the list is empty. If the thread/process crashed or terminated in some incorrect way then the list might be non-empty: in this case the kernel carefully walks the list [not trusting it], and marks all locks that are owned by this thread with the FUTEX_OWNER_DEAD bit, and wakes up one waiter (if any). The list is guaranteed to be private and per-thread, so it's lockless. There is one race possible though: since adding to and removing from the list is done after the futex is acquired by glibc, there is a few instructions window for the thread (or process) to die there, leaving the futex hung. To protect against this possibility, userspace (glibc) also maintains a simple per-thread 'list_op_pending' field, to allow the kernel to clean up if the thread dies after acquiring the lock, but just before it could have added itself to the list. Glibc sets this list_op_pending field before it tries to acquire the futex, and clears it after the list-add (or list-remove) has finished. That's all that is needed - all the rest of robust-futex cleanup is done in userspace [just like with the previous patches]. Ulrich Drepper has implemented the necessary glibc support for this new mechanism, which fully enables robust mutexes. (Ulrich plans to commit these changes to glibc-HEAD later today.) Key differences of this userspace-list based approach, compared to the vma based method: - it's much, much faster: at thread exit time, there's no need to loop over every vma (!), which the VM-based method has to do. Only a very simple 'is the list empty' op is done. - no VM changes are needed - 'struct address_space' is left alone. - no registration of individual locks is needed: robust mutexes dont need any extra per-lock syscalls. Robust mutexes thus become a very lightweight primitive - so they dont force the application designer to do a hard choice between performance and robustness - robust mutexes are just as fast. - no per-lock kernel allocation happens. - no resource limits are needed. - no kernel-space recovery call (FUTEX_RECOVER) is needed. - the implementation and the locking is "obvious", and there are no interactions with the VM. Performance ----------- I have benchmarked the time needed for the kernel to process a list of 1 million (!) held locks, using the new method [on a 2GHz CPU]: - with FUTEX_WAIT set [contended mutex]: 130 msecs - without FUTEX_WAIT set [uncontended mutex]: 30 msecs I have also measured an approach where glibc does the lock notification [which it currently does for !pshared robust mutexes], and that took 256 msecs - clearly slower, due to the 1 million FUTEX_WAKE syscalls userspace had to do. (1 million held locks are unheard of - we expect at most a handful of locks to be held at a time. Nevertheless it's nice to know that this approach scales nicely.) Implementation details ---------------------- The patch adds two new syscalls: one to register the userspace list, and one to query the registered list pointer: asmlinkage long sys_set_robust_list(struct robust_list_head __user *head, size_t len); asmlinkage long sys_get_robust_list(int pid, struct robust_list_head __user **head_ptr, size_t __user *len_ptr); List registration is very fast: the pointer is simply stored in current->robust_list. [Note that in the future, if robust futexes become widespread, we could extend sys_clone() to register a robust-list head for new threads, without the need of another syscall.] So there is virtually zero overhead for tasks not using robust futexes, and even for robust futex users, there is only one extra syscall per thread lifetime, and the cleanup operation, if it happens, is fast and straightforward. The kernel doesnt have any internal distinction between robust and normal futexes. If a futex is found to be held at exit time, the kernel sets the highest bit of the futex word: #define FUTEX_OWNER_DIED 0x40000000 and wakes up the next futex waiter (if any). User-space does the rest of the cleanup. Otherwise, robust futexes are acquired by glibc by putting the TID into the futex field atomically. Waiters set the FUTEX_WAITERS bit: #define FUTEX_WAITERS 0x80000000 and the remaining bits are for the TID. Testing, architecture support ----------------------------- I've tested the new syscalls on x86 and x86_64, and have made sure the parsing of the userspace list is robust [ ;-) ] even if the list is deliberately corrupted. i386 and x86_64 syscalls are wired up at the moment, and Ulrich has tested the new glibc code (on x86_64 and i386), and it works for his robust-mutex testcases. All other architectures should build just fine too - but they wont have the new syscalls yet. Architectures need to implement the new futex_atomic_cmpxchg_inuser() inline function before writing up the syscalls (that function returns -ENOSYS right now). This patch: Add placeholder futex_atomic_cmpxchg_inuser() implementations to every architecture that supports futexes. It returns -ENOSYS. Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Arjan van de Ven <arjan@infradead.org> Acked-by: Ulrich Drepper <drepper@redhat.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* | [PATCH] mips: add ptr_to_compat()Ingo Molnar2006-03-271-0/+5
| | | | | | | | | | | | | | | | | | Add ptr_to_compat() - needed by the new robust futex code. Signed-off-by: Ingo Molnar <mingo@elte.hu> Cc: Ralf Baechle <ralf@linux-mips.org> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* | [PATCH] unify pfn_to_page: mips pfn_to_pageKAMEZAWA Hiroyuki2006-03-272-16/+1
| | | | | | | | | | | | | | | | | | MIPS can use generic funcs. Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Ralf Baechle <ralf@linux-mips.org> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* | [PATCH] bitops: mips: use generic bitopsAkinobu Mita2006-03-261-449/+16
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | - remove __{,test_and_}{set,clear,change}_bit() and test_bit() - unless defined(CONFIG_CPU_MIPS32) or defined(CONFIG_CPU_MIPS64) - remove __ffs() - remove ffs() - remove ffz() - remove fls() - remove fls64() - remove find_{next,first}{,_zero}_bit() - remove sched_find_first_bit() - remove generic_hweight64() - remove generic_hweight{32,16,8}() - remove ext2_{set,clear,test,find_first_zero,find_next_zero}_bit() - remove ext2_{set,clear}_bit_atomic() - remove minix_{test,set,test_and_clear,test,find_first_zero}_bit() Signed-off-by: Akinobu Mita <mita@miraclelinux.com> Cc: Ralf Baechle <ralf@linux-mips.org> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* | [PATCH] bitops: use non atomic operations for minix_*_bit() and ext2_*_bit()Akinobu Mita2006-03-261-3/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Bitmap functions for the minix filesystem and the ext2 filesystem except ext2_set_bit_atomic() and ext2_clear_bit_atomic() do not require the atomic guarantees. But these are defined by using atomic bit operations on several architectures. (cris, frv, h8300, ia64, m32r, m68k, m68knommu, mips, s390, sh, sh64, sparc, sparc64, v850, and xtensa) This patch switches to non atomic bit operation. Signed-off-by: Akinobu Mita <mita@miraclelinux.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* | [PATCH] 2TB files: add blkcnt_tTakashi Sato2006-03-261-0/+5
|/ | | | | | | | | | | | | | | | | | | Add blkcnt_t as the type of inode.i_blocks. This enables you to make the size of blkcnt_t either 4 bytes or 8 bytes on 32 bits architecture with CONFIG_LSF. - CONFIG_LSF Add new configuration parameter. - blkcnt_t On h8300, i386, mips, powerpc, s390 and sh that define sector_t, blkcnt_t is defined as u64 if CONFIG_LSF is enabled; otherwise it is defined as unsigned long. On other architectures, it is defined as unsigned long. - inode.i_blocks Change the type from sector_t to blkcnt_t. Signed-off-by: Takashi Sato <sho@tnes.nec.co.jp> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] POLLRDHUP/EPOLLRDHUP handling for half-closed devices notificationsDavide Libenzi2006-03-251-0/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Implement the half-closed devices notifiation, by adding a new POLLRDHUP (and its alias EPOLLRDHUP) bit to the existing poll/select sets. Since the existing POLLHUP handling, that does not report correctly half-closed devices, was feared to be changed, this implementation leaves the current POLLHUP reporting unchanged and simply add a new bit that is set in the few places where it makes sense. The same thing was discussed and conceptually agreed quite some time ago: http://lkml.org/lkml/2003/7/12/116 Since this new event bit is added to the existing Linux poll infrastruture, even the existing poll/select system calls will be able to use it. As far as the existing POLLHUP handling, the patch leaves it as is. The pollrdhup-2.6.16.rc5-0.10.diff defines the POLLRDHUP for all the existing archs and sets the bit in the six relevant files. The other attached diff is the simple change required to sys/epoll.h to add the EPOLLRDHUP definition. There is "a stupid program" to test POLLRDHUP delivery here: http://www.xmailserver.org/pollrdhup-test.c It tests poll(2), but since the delivery is same epoll(2) will work equally. Signed-off-by: Davide Libenzi <davidel@xmailserver.org> Cc: "David S. Miller" <davem@davemloft.net> Cc: Michael Kerrisk <mtk-manpages@gmx.net> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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