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* uml: PATH_MAX needs limits.hIngo Molnar2008-06-06
| | | | | | | | | Include limits.h to get a definition of PATH_MAX. Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Jeff Dike <jdike@linux.intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* uml: stub needs to tolerate SIGWINCHJeff Dike2008-06-06
| | | | | | | | | | We lost the marking of SIGWINCH as being OK to receive during stub execution, causing a panic should that happen. Cc: Benedict Verheyen <benedict.verheyen@gmail.com> Signed-off-by: Jeff Dike <jdike@linux.intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* uml: memcpy export needs to follow host declarationJeff Dike2008-06-06
| | | | | | | | | | x86_64 defines either memcpy or __memcpy depending on the gcc version, and it looks like UML needs to follow that in its exporting. Cc: Gabriel C <nix.or.die@googlemail.com> Signed-off-by: Jeff Dike <jdike@linux.intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* uml: deal with inaccessible address space startTom Spink2008-06-06
| | | | | | | | | | | | | | | | | | | | | This patch makes os_get_task_size locate the bottom of the address space, as well as the top. This is for systems which put a lower limit on mmap addresses. It works by manually scanning pages from zero onwards until a valid page is found. Because the bottom of the address space may not be zero, it's not sufficient to assume the top of the address space is the size of the address space. The size is the difference between the top address and bottom address. [jdike@addtoit.com: changed the name to reflect that this function is supposed to return the top of the process address space, not its size and changed the return value to reflect that. Also some minor formatting changes] Signed-off-by: Tom Spink <tspink@gmail.com> Signed-off-by: Jeff Dike <jdike@linux.intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* uml: remove a duplicate includeHuang Weiyi2008-06-06
| | | | | | | | | | Removed duplicated include file "kern_util.h" in arch/um/drivers/ubd_kern.c. Signed-off-by: Huang Weiyi <weiyi.huang@gmail.com> Signed-off-by: Jeff Dike <jdike@linux.intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* uml: deal with host time going backwardsJeff Dike2008-06-06
| | | | | | | | | | | | Protection against the host's time going backwards (eg, ntp activity on the host) by keeping track of the time at the last tick and if it's greater than the current time, keep time stopped until the host catches up. Cc: Nix <nix@esperi.org.uk> Signed-off-by: Jeff Dike <jdike@linux.intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* thanks to net/mac80211 we need to pull drivers/leds/Kconfig on umlAl Viro2008-05-21
| | | | | Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* missing export of csum_partial() on uml/amd64Al Viro2008-05-21
| | | | | Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* uml: add missing exports for UML_RANDOM=mAl Viro2008-05-21
| | | | | Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* fix include order in sys-i386/registers.cAl Viro2008-05-21
| | | | | | | | | We want sys/ptrace.h before any includes of linux/ptrace.h and asm/user.h pulls the latter. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> Acked-by: Jeff Dike <jdike@addtoit.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* missed kmalloc() in pcap_user.cAl Viro2008-05-21
| | | | | | Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> Acked-by: Jeff Dike <jdike@addtoit.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* [PATCH] take init_files to fs/file.cAl Viro2008-05-16
| | | | Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* uml: track and make up lost ticksJeff Dike2008-05-13
| | | | | | | | | | | | Alarm delivery could be noticably late in the !CONFIG_NOHZ case because lost ticks weren't being taken into account. This is now treated more carefully, with the time between ticks being calculated and the appropriate number of ticks delivered to the timekeeping system. Cc: Nix <nix@esperi.org.uk> Signed-off-by: Jeff Dike <jdike@linux.intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* uml: style fixes in the random driverJeff Dike2008-05-13
| | | | | | | | Give random.c a style workover while I'm changing it. Signed-off-by: Jeff Dike <jdike@linux.intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* uml: random driver fixesJeff Dike2008-05-13
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The random driver would essentially hang if the host's /dev/random returned -EAGAIN. There was a test of need_resched followed by a schedule inside the loop, but that didn't help and it's the wrong way to work anyway. The right way is to ask for an interrupt when there is input available from the host and handle it then rather than polling. Now, when the host's /dev/random returns -EAGAIN, the driver asks for a wakeup when there's randomness available again and sleeps. The interrupt routine just wakes up whatever processes are sleeping on host_read_wait. There is an atomic_t, host_sleep_count, which counts the number of processes waiting for randomness. When this reaches zero, the interrupt is disabled. An added complication is that async I/O notification was only recently added to /dev/random (by me), so essentially all hosts will lack it. So, we use the sigio workaround here, which is to have a separate thread poll on the descriptor and send an interrupt when there is input on it. This mechanism is activated when a process gets -EAGAIN (activating this multiple times is harmless, if a bit wasteful) and deactivated by the last process still waiting. The module name was changed from "random" to "hw_random" in order for udev to recognize it. The sigio workaround needed some changes. sigio_broken was added for cases when we know that async notification doesn't work. This is now called from maybe_sigio_broken, which deals with pts devices. Signed-off-by: Jeff Dike <jdike@linux.intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* uml: physical memory shouldn't include initial stackJeff Dike2008-05-13
| | | | | | | | | | | | The top of physical memory should be below the initial process stack, not the top of the address space, at least for as long as the stack isn't known to the kernel VM system and appropriately reserved. Cc: "Christopher S. Aker" <caker@theshore.net> Signed-off-by: Jeff Dike <jdike@linux.intel.com> Cc: WANG Cong <xiyou.wangcong@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* uml: use PAGE_SIZE in linker scriptsCyrill Gorcunov2008-05-13
| | | | | | | | | | | | | | | This patch includes page.h header into linker scripts that allow us to use PAGE_SIZE macro instead of numeric constant. To be able to include page.h into linker scripts page.h is needed for some modification - i.e. we need to use __ASSEMBLY__ and _AC macro [jdike@linux.intel.com - fixed conflict with as-layout.h] Signed-off-by: Cyrill Gorcunov <gorcunov@gmail.com> Signed-off-by: Jeff Dike <jdike@linux.intel.com> Cc: WANG Cong <xiyou.wangcong@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* uml: use DIV_ROUND_UPJiri Olsa2008-05-13
| | | | | | | | | | | I just saw similar patches in the janitor kernel's list, and spotted place it fits. Signed-off-by: Jiri Olsa <olsajiri@gmail.com> Signed-off-by: Jeff Dike <jdike@linux.intel.com> Cc: WANG Cong <xiyou.wangcong@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* uml: fix CONFIG_RAW dependenciesRobert P. J. Day2008-05-13
| | | | | | | | | | | | | Add the BLOCK dependency for RAW_DRIVER, to match what's in drivers/char/Kconfig. Also, while we're there, update the alleged obsolesence of RAW_DRIVER since it doesn't seem to be going away any time soon. Signed-off-by: Robert P. J. Day <rpjday@crashcourse.ca> Signed-off-by: Jeff Dike <jdike@linux.intel.com> Cc: WANG Cong <xiyou.wangcong@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* uml: use __SPIN_LOCK_UNLOCKEDJeff Dike2008-05-13
| | | | | | | | | | | | From: Robert P. J. Day <rpjday@crashcourse.ca> Use newer, non-deprecated __SPIN_LOCK_UNLOCKED macro. Signed-off-by: Robert P. J. Day <rpjday@crashcourse.ca> Signed-off-by: Jeff Dike <jdike@linux.intel.com> Cc: WANG Cong <xiyou.wangcong@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* uml: fix bad NTP interaction with clockJeff Dike2008-05-13
| | | | | | | | | | | | | | | | UML's supposed nanosecond clock interacts badly with NTP when NTP decides that the clock has drifted ahead and needs to be slowed down. Slowing down the clock is done by decrementing the cycle-to-nanosecond multiplier, which is 1. Decrementing that gives you 0 and time is stopped. This is fixed by switching to a microsecond clock, with a multiplier of 1000. Signed-off-by: Jeff Dike <jdike@linux.intel.com> Cc: WANG Cong <xiyou.wangcong@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* uml: fix build when SLOB is enabledJeff Dike2008-05-13
| | | | | | | | | | | | | | | | | | Reintroduce uml_kmalloc for the benefit of UML libc code. The previous tactic of declaring __kmalloc so it could be called directly from the libc side of the house turned out to be getting too intimate with slab, and it doesn't work with slob. So, the uml_kmalloc wrapper is back. It calls kmalloc or whatever that translates into, and libc code calls it. kfree is left alone since that still works, leaving a somewhat inconsistent API. Signed-off-by: Jeff Dike <jdike@linux.intel.com> Cc: WANG Cong <xiyou.wangcong@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* uml: fix errno returnJohann Felix Soden2008-05-13
| | | | | | | | | | Error returns are negative. Signed-off-by: Johann Felix Soden <johfel@users.sourceforge.net> Signed-off-by: Jeff Dike <jdike@linux.intel.com> Cc: WANG Cong <xiyou.wangcong@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* uml: tidy ptrace interfaceJeff Dike2008-05-13
| | | | | | | | | | Tidy the ptrace interface code. Removed a bunch of unused macros. Started converting register sets from arrays of longs to structures. Signed-off-by: Jeff Dike <jdike@linux.intel.com> Cc: WANG Cong <xiyou.wangcong@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* uml: style fixesJeff Dike2008-05-13
| | | | | | | | | A few random style fixes. Signed-off-by: Jeff Dike <jdike@linux.intel.com> Cc: WANG Cong <xiyou.wangcong@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* uml: redo host capability detection and disablingJeff Dike2008-05-13
| | | | | | | | | | | | | | | Redo how host capabilities are recorded at startup and disabled on the command line. There are now explicit variables saying what's been disabled by the command line rather than the implicitness of the have_* variable being zero. The capability variables now start at zero and are set to one as their capabilities are found to be present on the host. Signed-off-by: Jeff Dike <jdike@linux.intel.com> Cc: WANG Cong <xiyou.wangcong@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* uml: fix inconsistence due to tty_operation changeWANG Cong2008-05-08
| | | | | | | | | | | 'put_char' of 'struct tty_operations' has changed from 'void' into 'int'. This can also shut up compiler warnings. Cc: Jeff Dike <jdike@addtoit.com> Signed-off-by: WANG Cong <wangcong@zeuux.org> Acked-by: Alan Cox <alan@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* Revert "uml: fix gcc problem"Linus Torvalds2008-05-06
| | | | | | | | | | | | | | | | This reverts commit 22eecde2f9034764a3fd095eecfa3adfb8ec9a98. Uli reports that it breaks UML on x86-64 with the Fedora 8 gcc (gcc 4.1.2), causing a crash on startup. See http://marc.info/?l=linux-kernel&m=121011722806093&w=2 for a trace. Reported-by: Ulrich Drepper <drepper@redhat.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* uml: fix gcc problemIngo Molnar2008-05-04
| | | | | | | | this is what caused gcc 4.3 to throw an internal error when OPTIMIZE_INLINING was enabled ... Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
* unified (weak) sys_pipe implementationUlrich Drepper2008-05-03
| | | | | | | | | | | | | | | | | | | This replaces the duplicated arch-specific versions of "sys_pipe()" with one unified implementation. This removes almost 250 lines of duplicated code. It's marked __weak, so that *if* an architecture wants to override the default implementation it can do so by simply having its own replacement version, since many architectures use alternate calling conventions for the 'pipe()' system call for legacy reasons (ie traditional UNIX implementations often return the two file descriptors in registers) I still haven't changed the cris version even though Linus says the BKL isn't needed. The arch maintainer can easily do it if there are really no obstacles. Signed-off-by: Ulrich Drepper <drepper@redhat.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* proc: remove proc_root from driversAlexey Dobriyan2008-04-29
| | | | | | | | | | | | Remove proc_root export. Creation and removal works well if parent PDE is supplied as NULL -- it worked always that way. So, one useless export removed and consistency added, some drivers created PDEs with &proc_root as parent but removed them as NULL and so on. Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* proper extern for late_time_initAdrian Bunk2008-04-29
| | | | | | | | | | | Add a proper extern for late_time_init in include/linux/init.h Signed-off-by: Adrian Bunk <bunk@kernel.org> Acked-by: Ingo Molnar <mingo@elte.hu> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: john stultz <johnstul@us.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* uml: clean up arch/um/drivers/ubd_kern.cWANG Cong2008-04-28
| | | | | | | | | | | | | Make some global functions and variables static. And remove some useless declarations for local functions, since we just need to move their definitions ahead. [jdike@addtoit.com: checkpatch cleanups] Signed-off-by: WANG Cong <wangcong@zeuux.org> Signed-off-by: Jeff Dike <jdike@addtoit.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* arch/um/os-Linux/sys-i386/task_size.c: improve a bitWANG Cong2008-04-28
| | | | | | | | | | Improve this code a bit: check sigaction's return value and remove a useless fflush(). Acked-by: Jeff Dike <jdike@addtoit.com> Signed-off-by: WANG Cong <wangcong@zeuux.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* uml: make several things staticWANG Cong2008-04-28
| | | | | | | | | Make several things static, because they no longer need to be global. Acked-by: Jeff Dike <jdike@addtoit.com> Signed-off-by: WANG Cong <wangcong@zeuux.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* uml: make three functions staticWANG Cong2008-04-28
| | | | | | | | | | | | | Make the following three functions static, since they don't need to be global. arch/um/drivers/mcast_kern.c::mcast_setup() arch/um/drivers/mconsole_user.c::mconsole_reply_v0() arch/um/drivers/port_user.c::port_pre_exec() Acked-by: Jeff Dike <jdike@addtoit.com> Signed-off-by: WANG Cong <wangcong@zeuux.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* uml: remove a useless functionWANG Cong2008-04-28
| | | | | | | | | arch/um/drivers/chan_kern.c::chan_out_fd() is not used by anyone. Remove it. Acked-by: Jeff Dike <jdike@addtoit.com> Signed-off-by: WANG Cong <wangcong@zeuux.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* uml: make a function staticWANG Cong2008-04-28
| | | | | | | | | arch/um/drivers/chan_kern.c::open_chan() can become static. Acked-by: Jeff Dike <jdike@addtoit.com> Signed-off-by: WANG Cong <wangcong@zeuux.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* arch/um/os-Linux/start_up.c: various improvements.WANG Cong2008-04-28
| | | | | | | | | | | - lets ptrace_child become void - adds checking for the return value of change_sig - moves errors info into stderr instead of stdout. Cc: Jeff Dike <jdike@addtoit.com> Signed-off-by: WANG Cong <wangcong@zeuux.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* uml: replace remaining __FUNCTION__ occurrencesHarvey Harrison2008-04-28
| | | | | | | | | __FUNCTION__ is gcc-specific, use __func__ Signed-off-by: Harvey Harrison <harvey.harrison@gmail.com> Cc: Jeff Dike <jdike@addtoit.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* arch/um/kernel/um_arch.c: some small improvementsWANG Cong2008-04-28
| | | | | | | | | Make some small improvements for arch/um/kernel/um_arch.c. Signed-off-by: WANG Cong <xiyou.wangcong@gmail.com> Acked-by: Jeff Dike <jdike@addtoit.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* x86, bitops: select the generic bitmap search functionsAlexander van Heukelum2008-04-26
| | | | | | | | | | | | | | | | | | Introduce GENERIC_FIND_FIRST_BIT and GENERIC_FIND_NEXT_BIT in lib/Kconfig, defaulting to off. An arch that wants to use the generic implementation now only has to use a select statement to include them. I added an always-y option (X86_CPU) to arch/x86/Kconfig.cpu and used that to select the generic search functions. This way ARCH=um SUBARCH=i386 automatically picks up the change too, and arch/um/Kconfig.i386 can therefore be simplified a bit. ARCH=um SUBARCH=x86_64 does things differently, but still compiles fine. It seems that a "def_bool y" always wins over a "def_bool n"? Signed-off-by: Alexander van Heukelum <heukelum@fastmail.fm> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* x86, UML: remove x86-specific implementations of find_first_bitAlexander van Heukelum2008-04-26
| | | | | | | | | | | x86 has been switched to the generic versions of find_first_bit and find_first_zero_bit, but the original versions were retained. This patch just removes the now unused x86-specific versions. also update UML. Signed-off-by: Alexander van Heukelum <heukelum@fastmail.fm> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* x86, uml: fix uml with generic find_next_bit for x86Alexander van Heukelum2008-04-26
| | | | | | | Update UML to use the generic bits too. Signed-off-by: Alexander van Heukelum <heukelum@fastmail.fm> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* uml: Kconfig cleanupIngo Molnar2008-04-26
| | | | | | | | pointed out by Linus: arch/um/Kconfig.x86_64 should include arch/x86/Kconfig.cpu instead of defining those symbols itself. Signed-off-by: Ingo Molnar <mingo@elte.hu>
* uml: fix build errorIngo Molnar2008-04-26
| | | | | | | | | fix: arch/um/os-Linux/helper.c: In function 'run_helper': arch/um/os-Linux/helper.c:73: error: 'PATH_MAX' undeclared (first use in this function) Signed-off-by: Ingo Molnar <mingo@elte.hu>
* Generic semaphore implementationMatthew Wilcox2008-04-17
| | | | | | | | | | | Semaphores are no longer performance-critical, so a generic C implementation is better for maintainability, debuggability and extensibility. Thanks to Peter Zijlstra for fixing the lockdep warning. Thanks to Harvey Harrison for pointing out that the unlikely() was unnecessary. Signed-off-by: Matthew Wilcox <willy@linux.intel.com> Acked-by: Ingo Molnar <mingo@elte.hu>
* [UML]: uml-net: don't set IFF_ALLMULTI in set_multicast_listPatrick McHardy2008-03-26
| | | | | | | | | | | | IFF_ALLMULTI is an indication from the network stack to the driver to disable multicast filters, drivers should never set it directly. Since the UML networking device doesn't have any filtering capabilites, it doesn't the set_multicast_list function at all, it is kept so userspace can still issue SIOCADDMULTI/SIOCDELMULTI ioctls however. Signed-off-by: Patrick McHardy <kaber@trash.net> Signed-off-by: David S. Miller <davem@davemloft.net>
* sched: add declaration of sched_tail to sched.hHarvey Harrison2008-02-25
| | | | | | | | | | Avoids sparse warnings: kernel/sched.c:2170:17: warning: symbol 'schedule_tail' was not declared. Should it be static? Avoids the need for an external declaration in arch/um/process.c Signed-off-by: Harvey Harrison <harvey.harrison@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* uml: fix FP register corruptionJeff Dike2008-02-23
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Commit ee3d9bd4de1ed93d2a7ee41c331ed30a1c7b8acd ("uml: simplify SIGSEGV handling"), while greatly simplifying the kernel SIGSEGV handler that runs in the process address space, introduced a bug which corrupts FP state in the process. Previously, the SIGSEGV handler called the sigreturn system call by hand - it couldn't return through the restorer provided to it because that could try to call the libc restorer which likely wouldn't exist in the process address space. So, it blocked off some signals, including SIGUSR1, on entry to the SIGSEGV handler, queued a SIGUSR1 to itself, and invoked sigreturn. The SIGUSR1 was delivered, and was visible to the UML kernel after sigreturn finished. The commit eliminated the signal masking and the call to sigreturn. The handler simply hits itself with a SIGTRAP to let the UML kernel know that it is finished. UML then restores the process registers, which effectively longjmps the process out of the signal handler, skipping sigreturn's restoring of register state and the signal mask. The bug is that the host apparently sets used_fp to 0 when it saves the process FP state in the sigcontext on the process signal stack. Thus, when the process is longjmped out of the handler, its FP state is corrupt because it wasn't saved on the context switch to the UML kernel. This manifested itself as sleep hanging. For some reason, sleep uses floating point in order to calculate the sleep interval. When a page fault corrupts its FP state, it is faked into essentially sleeping forever. This patch saves the FP state before entering the SIGSEGV handler and restores it afterwards. Signed-off-by: Jeff Dike <jdike@linux.intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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