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* [SPARC64]: Use compat_sys_futimesat in 32-bit syscall table.David S. Miller2006-01-20
| | | | Signed-off-by: David S. Miller <davem@davemloft.net>
* [SPARC]: Add support for *at(), ppoll, and pselect syscalls.David S. Miller2006-01-19
| | | | | | | | | | This also includes by necessity _TIF_RESTORE_SIGMASK support, which actually resulted in a lot of cleanups. The sparc signal handling code is quite a mess and I should clean it up some day. Signed-off-by: David S. Miller <davem@davemloft.net>
* [PATCH] vfs: *at functions: coreUlrich Drepper2006-01-18
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Here is a series of patches which introduce in total 13 new system calls which take a file descriptor/filename pair instead of a single file name. These functions, openat etc, have been discussed on numerous occasions. They are needed to implement race-free filesystem traversal, they are necessary to implement a virtual per-thread current working directory (think multi-threaded backup software), etc. We have in glibc today implementations of the interfaces which use the /proc/self/fd magic. But this code is rather expensive. Here are some results (similar to what Jim Meyering posted before). The test creates a deep directory hierarchy on a tmpfs filesystem. Then rm -fr is used to remove all directories. Without syscall support I get this: real 0m31.921s user 0m0.688s sys 0m31.234s With syscall support the results are much better: real 0m20.699s user 0m0.536s sys 0m20.149s The interfaces are for obvious reasons currently not much used. But they'll be used. coreutils (and Jeff's posixutils) are already using them. Furthermore, code like ftw/fts in libc (maybe even glob) will also start using them. I expect a patch to make follow soon. Every program which is walking the filesystem tree will benefit. Signed-off-by: Ulrich Drepper <drepper@redhat.com> Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com> Cc: Christoph Hellwig <hch@lst.de> Cc: Al Viro <viro@ftp.linux.org.uk> Acked-by: Ingo Molnar <mingo@elte.hu> Cc: Michael Kerrisk <mtk-manpages@gmx.net> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [SPARC64]: Fix build with CONFIG_COMPAT disabled.David S. Miller2006-01-18
| | | | | | Based upon a report and preliminary patch from Jim Gifford. Signed-off-by: David S. Miller <davem@davemloft.net>
* [SPARC64]: Serial Console for E250 PatchEddie C. Dost2006-01-18
| | | | | | | | | | | | | | From: Eddie C. Dost <ecd@brainaid.de> I have the following patch for serial console over the RSC (remote system controller) on my E250 machine. It basically adds support for input-device=rsc and output-device=rsc from OBP, and allows 115200,8,n,1,- serial mode setting. Signed-off-by: David S. Miller <davem@davemloft.net>
* [SPARC64]: Eliminate race condition reading Hummingbird STICK registerRichard Mortimer2006-01-17
| | | | | | | | | | | | | | | | | | | | | | | | | | | Ensure a consistent value is read from the STICK register by ensuring that both high and low are read without high changing due to a roll over of the low register. Various Debian/SPARC users (myself include) have noticed problems with Hummingbird based systems. The symptoms are that the system time is seen to jump forward 3 days, 6 hours, 11 minutes give or take a few seconds. In many cases the system then hangs some time afterwards. I've spotted a race condition in the code to read the STICK register. I could not work out why 3d, 6h, 11m is important but guess that it is due to the 2^32 jump of STICK (forwards on one read and then the next read will seem to be backwards) during a timer interrupt. I'm guessing that a change of -2^32 will get converted to a large unsigned increment after the arithmetic manipulation between STICK, nanoseconds, jiffies etc. I did a test where I modified __hbird_read_stick to artificially inject rollover faults forcefully every few seconds. With this I saw the clock jump over 6 times in 12 hours compared to once every month or so. Signed-off-by: Richard Mortimer <richm@oldelvet.org.uk> Signed-off-by: David S. Miller <davem@davemloft.net>
* [PATCH] sparc64: task_pt_regs()Al Viro2006-01-12
| | | | | | Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] sparc64: task_stack_page()Al Viro2006-01-12
| | | | | | Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] sparc64: task_thread_info()Al Viro2006-01-12
| | | | | | Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] capable/capability.h (arch/)Randy Dunlap2006-01-11
| | | | | | | | arch: Use <linux/capability.h> where capable() is used. Signed-off-by: Randy Dunlap <rdunlap@xenotime.net> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] kprobes: fix race in recovery of reentrant probeKeshavamurthy Anil S2006-01-11
| | | | | | | | | | | | | | | | | There is a window where a probe gets removed right after the probe is hit on some different cpu. In this case probe handlers can't find a matching probe instance related to break address. In this case we need to read the original instruction at break address to see if that is not a break/int3 instruction and recover safely. Previous code had a bug where we were not checking for the above race in case of reentrant probes and the below patch fixes this race. Tested on IA64, Powerpc, x86_64. Signed-off-by: Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* Merge master.kernel.org:/pub/scm/linux/kernel/git/davem/sparc-2.6Linus Torvalds2006-01-10
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| * [SPARC64]: Fix sys_fstat64() entry in 64-bit syscall table.David S. Miller2006-01-09
| | | | | | | | | | | | Noticed by Jakub Jelinek. Signed-off-by: David S. Miller <davem@davemloft.net>
* | [PATCH] kprobes: arch_remove_kprobeAnil S Keshavamurthy2006-01-10
| | | | | | | | | | | | | | | | | | | | | | | | | | Currently arch_remove_kprobes() is only implemented/required for x86_64 and powerpc. All other architecture like IA64, i386 and sparc64 implementes a dummy function which is being called from arch independent kprobes.c file. This patch removes the dummy functions and replaces it with #define arch_remove_kprobe(p, s) do { } while(0) Signed-off-by: Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* | [PATCH] kprobes: changed from using spinlock to mutexAnil S Keshavamurthy2006-01-10
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Since Kprobes runtime exception handlers is now lock free as this code path is now using RCU to walk through the list, there is no need for the register/unregister{_kprobe} to use spin_{lock/unlock}_isr{save/restore}. The serialization during registration/unregistration is now possible using just a mutex. In the above process, this patch also fixes a minor memory leak for x86_64 and powerpc. Signed-off-by: Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* | [PATCH] sanitize building of fs/compat_ioctl.cChristoph Hellwig2006-01-10
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Now that all these entries in the arch ioctl32.c files are gone [1], we can build fs/compat_ioctl.c as a normal object and kill tons of cruft. We need a special do_ioctl32_pointer handler for s390 so the compat_ptr call is done. This is not needed but harmless on all other architectures. Also remove some superflous includes in fs/compat_ioctl.c Tested on ppc64. [1] parisc still had it's PPP handler left, which is not fully correct for ppp and besides that ppp uses the generic SIOCPRIV ioctl so it'd kick in for all netdevice users. We can introduce a proper handler in one of the next patch series by adding a compat_ioctl method to struct net_device but for now let's just kill it - parisc doesn't compile in mainline anyway and I don't want this to block this patchset. Signed-off-by: Christoph Hellwig <hch@lst.de> Cc: Matthew Wilcox <willy@debian.org> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* | [PATCH] common compat_sys_timer_createChristoph Hellwig2006-01-10
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The comment in compat.c is wrong, every architecture provides a get_compat_sigevent() for the IPC compat code already. This basically moves the x86_64 version to common code and removes all the others. Signed-off-by: Christoph Hellwig <hch@lst.de> Acked-by: Paul Mackerras <paulus@samba.org> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: "David S. Miller" <davem@davemloft.net> Acked-by: Andi Kleen <ak@muc.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* | [PATCH] dump_thread() cleanupakpm@osdl.org2006-01-10
|/ | | | | | | | | | | | | | | | ) From: Adrian Bunk <bunk@stusta.de> - create one common dump_thread() prototype in kernel.h - dump_thread() is only used in fs/binfmt_aout.c and can therefore be removed on all architectures where CONFIG_BINFMT_AOUT is not available Signed-off-by: Adrian Bunk <bunk@stusta.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* Merge master.kernel.org:/pub/scm/linux/kernel/git/gregkh/pci-2.6Linus Torvalds2006-01-09
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| * [PATCH] PCI: pci_find_device remove (sparc64/kernel/ebus.c)Jiri Slaby2006-01-09
| | | | | | | | | | | | Signed-off-by: Jiri Slaby <xslaby@fi.muni.cz> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
* | [SPARC64]: Fix ptrace/straceRichard Mortimer2006-01-09
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Don't clobber register %l0 while checking TI_SYS_NOERROR value in syscall return path. This bug was introduced by: db7d9a4eb700be766cc9f29241483dbb1e748832 Problem narrowed down by Luis F. Ortiz and Richard Mortimer. I tried using %l2 as suggested by Luis and that works for me. Looking at the code I wonder if it makes sense to simplify the code a little bit. The following works for me but I'm not sure how to exercise the "NOERROR" codepath. Signed-off-by: David S. Miller <davem@davemloft.net>
* | [SPARC64]: Add needed pm_power_off symbol.David S. Miller2006-01-09
|/ | | | Signed-off-by: David S. Miller <davem@davemloft.net>
* [PATCH] use ptrace_get_task_struct in various placesChristoph Hellwig2006-01-08
| | | | | | | | | | | | | | | | The ptrace_get_task_struct() helper that I added as part of the ptrace consolidation is useful in variety of places that currently opencode it. Switch them to the common helpers. Add a ptrace_traceme() helper that needs to be explicitly called, and simplify the ptrace_get_task_struct() interface. We don't need the request argument now, and we return the task_struct directly, using ERR_PTR() for error returns. It's a bit more code in the callers, but we have two sane routines that do one thing well now. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [SPARC]: Use STABS_DEBUG and DWARF_DEBUG macros in vmlinux.lds.SDavid S. Miller2005-12-28
| | | | Signed-off-by: David S. Miller <davem@davemloft.net>
* [SPARC]: Kill CHILD_MAX.David S. Miller2005-12-23
| | | | | | | | | | | It's definition is wrong (-1 means "no limit" not 999), only the Sparc SunOS/Solaris compat code uses it, so let's just kill it off completely from limits.h and all referencing code. Noticed by Ulrich Drepper. Signed-off-by: David S. Miller <davem@davemloft.net>
* [PATCH] kprobes: increment kprobe missed count for multiprobesKeshavamurthy Anil S2005-12-12
| | | | | | | | | | | | | | When multiple probes are registered at the same address and if due to some recursion (probe getting triggered within a probe handler), we skip calling pre_handlers and just increment nmissed field. The below patch make sure it walks the list for multiple probes case. Without the below patch we get incorrect results of nmissed count for multiple probe case. Signed-off-by: Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] unpaged: fix sound Bad page statesHugh Dickins2005-11-22
| | | | | | | | | | | | | | | | | | Earlier I unifdefed PageCompound, so that snd_pcm_mmap_control_nopage and others can give out a 0-order component of a higher-order page, which won't be mistakenly freed when zap_pte_range unmaps it. But many Bad page states reported a PG_reserved was freed after all: I had missed that we need to say __GFP_COMP to get compound page behaviour. Some of these higher-order pages are allocated by snd_malloc_pages, some by snd_malloc_dev_pages; or if SBUS, by sbus_alloc_consistent - but that has no gfp arg, so add __GFP_COMP into its sparc32/64 implementations. I'm still rather puzzled that DRM seems not to need a similar change. Signed-off-by: Hugh Dickins <hugh@veritas.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [SBUSFB]: implement ->compat_ioctlChristoph Hellwig2005-11-12
| | | | | | | | | | | | | This patch adds a new function, sbusfb_compat_ioctl() to drivers/video/sbuslib.c and uses it as compat_ioctl in all sbus fb drivers This remove the last per-arch compat ioctl bits in arch/sparc64/kernel/ioctl32.c so it would be nice if people could test if this actually copiles and works and if yes apply it :) Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: David S. Miller <davem@davemloft.net>
* [SPARC64]: Restore 2.4.x /proc/cpuinfo behavior for "ncpus probed" field.David S. Miller2005-11-11
| | | | | | | | | | | | | | Noticed by Tom 'spot' Callaway. Even on uniprocessor we always reported the number of physical cpus in the system via /proc/cpuinfo. But when this got changed to use num_possible_cpus() it always reads as "1" on uniprocessor. This change was unintentional. So scan the firmware device tree and count the number of cpu nodes, and report that, as we always did. Signed-off-by: David S. Miller <davem@davemloft.net>
* [SPARC] sbus rtc: implement ->compat_ioctlChristoph Hellwig2005-11-09
| | | | | Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: David S. Miller <davem@davemloft.net>
* [SPARC64]: Use ARRAY_SIZE macroTobias Klauser2005-11-09
| | | | | | | | Use ARRAY_SIZE macro instead of sizeof(x)/sizeof(x[0]) and remove a duplicate of ARRAY_SIZE which is never used anyways. Signed-off-by: Tobias Klauser <tklauser@nuerscht.ch> Signed-off-by: David S. Miller <davem@davemloft.net>
* [PATCH] sched: resched and cpu_idle reworkNick Piggin2005-11-09
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Make some changes to the NEED_RESCHED and POLLING_NRFLAG to reduce confusion, and make their semantics rigid. Improves efficiency of resched_task and some cpu_idle routines. * In resched_task: - TIF_NEED_RESCHED is only cleared with the task's runqueue lock held, and as we hold it during resched_task, then there is no need for an atomic test and set there. The only other time this should be set is when the task's quantum expires, in the timer interrupt - this is protected against because the rq lock is irq-safe. - If TIF_NEED_RESCHED is set, then we don't need to do anything. It won't get unset until the task get's schedule()d off. - If we are running on the same CPU as the task we resched, then set TIF_NEED_RESCHED and no further action is required. - If we are running on another CPU, and TIF_POLLING_NRFLAG is *not* set after TIF_NEED_RESCHED has been set, then we need to send an IPI. Using these rules, we are able to remove the test and set operation in resched_task, and make clear the previously vague semantics of POLLING_NRFLAG. * In idle routines: - Enter cpu_idle with preempt disabled. When the need_resched() condition becomes true, explicitly call schedule(). This makes things a bit clearer (IMO), but haven't updated all architectures yet. - Many do a test and clear of TIF_NEED_RESCHED for some reason. According to the resched_task rules, this isn't needed (and actually breaks the assumption that TIF_NEED_RESCHED is only cleared with the runqueue lock held). So remove that. Generally one less locked memory op when switching to the idle thread. - Many idle routines clear TIF_POLLING_NRFLAG, and only set it in the inner most polling idle loops. The above resched_task semantics allow it to be set until before the last time need_resched() is checked before going into a halt requiring interrupt wakeup. Many idle routines simply never enter such a halt, and so POLLING_NRFLAG can be always left set, completely eliminating resched IPIs when rescheduling the idle task. POLLING_NRFLAG width can be increased, to reduce the chance of resched IPIs. Signed-off-by: Nick Piggin <npiggin@suse.de> Cc: Ingo Molnar <mingo@elte.hu> Cc: Con Kolivas <kernel@kolivas.org> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] sched: disable preempt in idle tasksNick Piggin2005-11-09
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Run idle threads with preempt disabled. Also corrected a bugs in arm26's cpu_idle (make it actually call schedule()). How did it ever work before? Might fix the CPU hotplugging hang which Nigel Cunningham noted. We think the bug hits if the idle thread is preempted after checking need_resched() and before going to sleep, then the CPU offlined. After calling stop_machine_run, the CPU eventually returns from preemption and into the idle thread and goes to sleep. The CPU will continue executing previous idle and have no chance to call play_dead. By disabling preemption until we are ready to explicitly schedule, this bug is fixed and the idle threads generally become more robust. From: alexs <ashepard@u.washington.edu> PPC build fix From: Yoichi Yuasa <yuasa@hh.iij4u.or.jp> MIPS build fix Signed-off-by: Nick Piggin <npiggin@suse.de> Signed-off-by: Yoichi Yuasa <yuasa@hh.iij4u.or.jp> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] remove ioctl32_handler_tChristoph Hellwig2005-11-09
| | | | | | | | | | | Some architectures define and use this type in their compat_ioctl code, but all of them can easily use the identical ioctl_trans_handler_t type that is defined in common code. Signed-off-by: Christoph Hellwig <hch@lst.de> Cc: Andi Kleen <ak@muc.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [SPARC64]: Kill some unnecessary includes from ioctl32.cDavid S. Miller2005-11-07
| | | | Signed-off-by: David S. Miller <davem@davemloft.net>
* [SPARC64]: remove drm compat ioctl handlingChristoph Hellwig2005-11-07
| | | | | | | | drivers/drm/ now implements proper ->compat_ioctl methods, so this isn't needed anymore. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: David S. Miller <davem@davemloft.net>
* [SPARC] cpwatchdog: implement ->compat_ioctlChristoph Hellwig2005-11-07
| | | | | Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: David S. Miller <davem@davemloft.net>
* [SPARC] display7seg: implement ->unlocked_ioctl and ->compat_ioctlChristoph Hellwig2005-11-07
| | | | | | | | all ioctls are 32bit compat clean, so the driver can use ->compat_ioctl and ->unlocked_ioctl easily. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: David S. Miller <davem@davemloft.net>
* [SPARC] openprom: implement ->compat_ioctlChristoph Hellwig2005-11-07
| | | | | | | | | implement a compat_ioctl handle in the driver instead of having table entries in sparc64 ioctl32.c (I plan to get rid of the arch ioctl32.c file eventually) Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: David S. Miller <davem@davemloft.net>
* [SPARC] envctrl: implement ->unlocked_ioctl and ->compat_ioctlChristoph Hellwig2005-11-07
| | | | | | | | all the ioctls in the driver are 32bit compat clean and don't need BKL, so we can switch it to ->unlocked_ioctl and ->compat_ioctl trivially. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: David S. Miller <davem@davemloft.net>
* [SPARC]: Kill remaining kbio.h references.Christoph Hellwig2005-11-07
| | | | | | | | Would you mind applying the following patch that kills those two + the m68k and Documentation/ references? Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: David S. Miller <davem@davemloft.net>
* [SPARC64]: remove duplicated compat ioctl entriesChristoph Hellwig2005-11-07
| | | | | | | all these are handled by fs/compat_ioctls.c already. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: David S. Miller <davem@davemloft.net>
* [SPARC]: remove vuid_event.hChristoph Hellwig2005-11-07
| | | | | | | | I don't know if we ever implemented this, but the only user in any 2.6 tree are the compat ioctls. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: David S. Miller <davem@davemloft.net>
* [SPARC]: remove kbio.hChristoph Hellwig2005-11-07
| | | | | | | | The old keyboard driver is gone in 2.6, so the only user left are the compat ioctls. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: David S. Miller <davem@davemloft.net>
* [SPARC]: remove audioio.hChristoph Hellwig2005-11-07
| | | | | | | | The old sound drivers are gone in 2.6, so the only user left are the compat ioctls. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: David S. Miller <davem@davemloft.net>
* [SPARC64]: remove alloc_user_space()Christoph Hellwig2005-11-07
| | | | | | | | this inline routine in arch/sparc64/kernel/ioctl32.c is completely unused and superceeded by compat_alloc_user_space() Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: David S. Miller <davem@davemloft.net>
* [SPARC64]: Kill off dummy_tick_ops.David S. Miller2005-11-07
| | | | | | | | It only serves to generate false-positive buildcheck warnings. Just set it initially to tick_operations which uses the v9 %tick register which every sparc64 processor has. Signed-off-by: David S. Miller <davem@davemloft.net>
* [SPARC64] mm: Do not flush TLB mm in tlb_finish_mmu()David S. Miller2005-11-07
| | | | | | | | | | It isn't needed any longer, as noted by Hugh Dickins. We still need the flush routines, due to the one remaining call site in hugetlb_prefault_arch_hook(). That can be eliminated at some later point, however. Signed-off-by: David S. Miller <davem@davemloft.net>
* [SPARC64] mm: context switch ptlockHugh Dickins2005-11-07
| | | | | | | | | | | | | | | | | | | | | | | | | | | sparc64 is unique among architectures in taking the page_table_lock in its context switch (well, cris does too, but erroneously, and it's not yet SMP anyway). This seems to be a private affair between switch_mm and activate_mm, using page_table_lock as a per-mm lock, without any relation to its uses elsewhere. That's fine, but comment it as such; and unlock sooner in switch_mm, more like in activate_mm (preemption is disabled here). There is a block of "if (0)"ed code in smp_flush_tlb_pending which would have liked to rely on the page_table_lock, in switch_mm and elsewhere; but its comment explains how dup_mmap's flush_tlb_mm defeated it. And though that could have been changed at any time over the past few years, now the chance vanishes as we push the page_table_lock downwards, and perhaps split it per page table page. Just delete that block of code. Which leaves the mysterious spin_unlock_wait(&oldmm->page_table_lock) in kernel/fork.c copy_mm. Textual analysis (supported by Nick Piggin) suggests that the comment was written by DaveM, and that it relates to the defeated approach in the sparc64 smp_flush_tlb_pending. Just delete this block too. Signed-off-by: Hugh Dickins <hugh@veritas.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* [SPARC64] mm: don't re-evaluate *ptepHugh Dickins2005-11-07
| | | | | | | | | | sparc64 prom_callback and new_setup_frame32 each operates on a user page table without holding lock, and no doubt they've good reason. But I'd feel more confident if they were to do a "pte = *ptep" and then operate on pte, rather than re-evaluating *ptep. Signed-off-by: Hugh Dickins <hugh@veritas.com> Signed-off-by: David S. Miller <davem@davemloft.net>
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