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2007-10-16uml: tickless supportJeff Dike
Enable tickless support. CONFIG_TICK_ONESHOT and CONFIG_NO_HZ are enabled. itimer_clockevent gets CLOCK_EVT_FEAT_ONESHOT and an implementation of .set_next_event. CONFIG_UML_REAL_TIME_CLOCK goes away because it only makes sense when there is a clock ticking away all the time. timer_handler now just calls do_IRQ once without trying to figure out how many ticks to emulate. The idle loop now needs to turn ticking on and off. Userspace ticks keep happening as usual. However, the userspace loop keep track of when the next wakeup should happen and suppresses process ticks until that happens. Signed-off-by: Jeff Dike <jdike@linux.intel.com> Cc: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-10-16uml: GENERIC_CLOCKEVENTS supportJeff Dike
Enable CONFIG_GENERIC_CLOCKEVENTS. timer_irq gets its name changed to timer_handler, and becomes the recipient of timer signals. The clock_event_device is set up to imitate the current ticking clock, i.e. CLOCK_EVT_FEAT_ONESHOT is not enabled yet. disable_timer now doesn't ignore SIGALRM and SIGVTALRM because that breaks delay calibration. Signed-off-by: Jeff Dike <jdike@linux.intel.com> Cc: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-10-16uml: separate timer initializationJeff Dike
Move timer signal initialization from init_irq_signals to a new function, timer_init. Signed-off-by: Jeff Dike <jdike@linux.intel.com> Cc: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-10-16uml: simplify interval settingJeff Dike
set_interval took a timer type as an argument, but it always specified a virtual timer. So, it is not needed, and it is gone, and set_interval is simplified appropriately. Signed-off-by: Jeff Dike <jdike@linux.intel.com> Cc: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-10-16uml: fix timer switchingJeff Dike
Fix up the switching between virtual and real timers. The idle loop sleeps, so the timer at that point must be real time. At all other times, the timer must be virtual. Even when userspace is running, and the kernel is asleep, the virtual timer is correct because the process timer will be running and the process timer will be firing. The timer switch used to be in the context switch and timer handler code. This is moved to the idle loop and the signal handler, making it much more clear why it is happening. switch_timers now returns the old timer type so that it may be restored. The signal handler uses this in order to restore the previous timer type when it returns. Signed-off-by: Jeff Dike <jdike@linux.intel.com> Cc: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-10-16uml: eliminate hz()Jeff Dike
Eliminate hz() since its only purpose was to provide a kernel-space constant to userspace code. This can be done instead by providing the constant directly through kernel_constants.h. Signed-off-by: Jeff Dike <jdike@linux.intel.com> Cc: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-10-16uml: remove unused fileJeff Dike
arch/um/os-Linux/tt.c is no longer used. 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>
2007-10-16uml: style fixes in FP codeJeff Dike
Tidy the code affected by the floating point fixes. A bunch of unused stuff is gone, including two sigcontext.c files, which turned out to be entirely unneeded. There are the usual fixes - whitespace and style cleanups copyright updates emacs formatting comments gone include cleanups adding severities to printks 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>
2007-10-16uml: floating point signal delivery fixesJeff Dike
Handle floating point state in across signals correctly. UML/i386 needs to know whether the host does PTRACE_[GS]ETFPXREGS, so an arch_init_registers hook is added, which on x86_64 does nothing. UML doesn't save and restore floating point registers on kernel entry and exit, so they need to be copied between the host process and the sigcontext. save_fpx_registers and restore_fpx_registers are added for this purpose. save_fp_registers and restore_fp_registers already exist. There was a bunch of floating point state conversion code in arch/um/sys-i386/ptrace.c which isn't needed there, but is needed in signal.c, so it is moved over. The i386 code now distinguishes between fp and fpx state and handles them correctly. The x86_64 code just needs to copy state as-is between the host process and the stack. There are also some fixes there to pass the correct address of the floating point state around. 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>
2007-10-16uml: userspace files should call libc directlyJeff Dike
A number of files that were changed in the recent removal of tt mode are userspace files which call the os_* wrappers instead of calling libc directly. A few other files were affected by this, through This patch makes these call glibc directly. There are also style fixes in the affected areas. os_print_error has no remaining callers, so it is deleted. There is a interface change to os_set_exec_close, eliminating a parameter which was always the same. The callers are fixed as well. os_process_pc got its error path cleaned up. 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>
2007-10-16uml: replace clone with forkJeff Dike
Convert the boot-time host ptrace testing from clone to fork. They were essentially doing fork anyway. This cleans up the code a bit, and makes valgrind a bit happier about grinding 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>
2007-10-16uml: remove os_* usage from userspace filesJeff Dike
This patch fixes some userspace files which were calling libc through the os_* wrappers. It turns out that there was only one user of os_new_tty_pgrp, so it can be deleted. There are also some style and whitespace fixes in here. 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>
2007-10-16uml: rename pt_regs general-purpose register fileJeff Dike
Before the removal of tt mode, access to a register on the skas-mode side of a pt_regs struct looked like pt_regs.regs.skas.regs.regs[FOO]. This was bad enough, but it became pt_regs.regs.regs.regs[FOO] with the removal of the union from the middle. To get rid of the run of three "regs", the last field is renamed to "gp". 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>
2007-10-16uml: get rid of do_longjmpJeff Dike
do_longjmp used to be needed when UML didn't have its own implementation of setjmp and longjmp. They came from libc, and couldn't be called directly from kernel code, as the libc jmp_buf couldn't be imported there. do_longjmp was a userspace function which served to provide longjmp access to kernel code. This is gone, and a number of void * pointers can now be jmp_buf *. 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>
2007-10-16uml: remove __u64 usage from physical memory subsystemJeff Dike
Eliminate some uses of __u64 in the physical memory support. It's hard to get a definition of __u64 in both kernel and userspace code on x86_64, so this changes them to unsigned long long. There are also a copyright update and formatting comment removal from the affected header. 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>
2007-10-16uml: style fixes pass 3Jeff Dike
Formatting changes in the files which have been changed in the course of folding foo_skas functions into their callers. These include: copyright updates header file trimming style fixes adding severity to printks These changes should be entirely non-functional. 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>
2007-10-16uml: remove code made redundant by CHOOSE_MODE removalJeff Dike
This patch makes a number of simplifications enabled by the removal of CHOOSE_MODE. There were lots of functions that looked like int foo(args){ foo_skas(args); } The bodies of foo_skas are now folded into foo, and their declarations (and sometimes entire header files) are deleted. In addition, the union uml_pt_regs, which was a union between the tt and skas register formats, is now a struct, with the tt-mode arm of the union being removed. It turns out that usr2_handler was unused, so it is gone. 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>
2007-10-16uml: throw out CHOOSE_MODEJeff Dike
The next stage after removing code which depends on CONFIG_MODE_TT is removing the CHOOSE_MODE abstraction, which provided both compile-time and run-time branching to either tt-mode or skas-mode code. This patch removes choose-mode.h and all inclusions of it, and replaces all CHOOSE_MODE invocations with the skas branch. This leaves a number of trivial functions which will be dealt with in a later patch. There are some changes in the uaccess and tls support which go somewhat beyond this and eliminate some of the now-redundant functions. 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>
2007-10-16uml: style fixes pass 1Jeff Dike
Formatting changes in the files which have been changed in the tt-removal patchset so far. These include: copyright updates header file trimming style fixes adding severity to printks indenting Kconfig help according to the predominant kernel style These changes should be entirely non-functional. 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>
2007-10-16uml: throw out CONFIG_MODE_TTJeff Dike
This patchset throws out tt mode, which has been non-functional for a while. This is done in phases, interspersed with code cleanups on the affected files. The removal is done as follows: remove all code, config options, and files which depend on CONFIG_MODE_TT get rid of the CHOOSE_MODE macro, which decided whether to call tt-mode or skas-mode code, and replace invocations with their skas portions replace all now-trivial procedures with their skas equivalents There are now a bunch of now-redundant pieces of data structures, including mode-specific pieces of the thread structure, pt_regs, and mm_context. These are all replaced with their skas-specific contents. As part of the ongoing style compliance project, I made a style pass over all files that were changed. There are three such patches, one for each phase, covering the files affected by that phase but no later ones. I noticed that we weren't freeing the LDT state associated with a process when it exited, so that's fixed in one of the later patches. The last patch is a tidying patch which I've had for a while, but which caused inexplicable crashes under tt mode. Since that is no longer a problem, this can now go in. This patch: Start getting rid of tt mode support. This patch throws out CONFIG_MODE_TT and all config options, code, and files which depend on it. CONFIG_MODE_SKAS is gone and everything that depends on it is included unconditionally. The few changed lines are in re-written Kconfig help, lines which needed something skas-related removed from them, and a few more which weren't strictly deletions. 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>
2007-10-16uml: stop saving process FP stateJeff Dike
Throw out a lot of code dealing with saving and restoring floating-point state. In skas mode, where processes run in a restoring floating-point state on kernel entry and exit is pointless. This eliminates most of arch/um/os-Linux/sys-{i386,x86_64}/registers.c. Most of what remained is now arch-indpendent, and can be moved up to arch/um/os-Linux/registers.c. Both arches need the jmp_buf accessor get_thread_reg, and i386 needs {save,restore}_fp_regs because it cheats during sigreturn by getting the fp state using ptrace rather than copying it out of the process sigcontext. After this, it turns out that arch/um/include/skas/mode-skas.h is almost completely unneeded. The declarations in it are variables which either don't exist or which don't have global scope. The one exception is kill_off_processes_skas. If that's removed, this header can be deleted. This uncovered a bug in user.h, which wasn't correctly making sure that a size_t definition was available to both userspace and kernelspace files. 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>
2007-10-16uml: stop using libc asm/page.hJeff Dike
Remove includes of asm/page.h from libc code. This header seems to be disappearing, and UML doesn't make much use of it anyway. The one use, PAGE_SHIFT in stub.h, is handled by copying the constant from the kernel side of the house in common_offsets.h. 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>
2007-10-16uml: tidy recently-moved codeJeff Dike
Now that the generic console operations are in a userspace file, we can do the following: directly call into libc instead of through the os_* wrappers eliminate os_window_size since it has only one user Signed-off-by: Jeff Dike <jdike@linux.intel.com> Cc: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-09-19uml: fix irqstack crashJeff Dike
This patch fixes a crash caused by an interrupt coming in when an IRQ stack is being torn down. When this happens, handle_signal will loop, setting up the IRQ stack again because the tearing down had finished, and handling whatever signals had come in. However, to_irq_stack returns a mask of pending signals to be handled, plus bit zero is set if the IRQ stack was already active, and thus shouldn't be torn down. This causes a problem because when handle_signal goes around the loop, sig will be zero, and to_irq_stack will duly set bit zero in the returned mask, faking handle_signal into believing that it shouldn't tear down the IRQ stack and return thread_info pointers back to their original values. This will eventually cause a crash, as the IRQ stack thread_info will continue pointing to the original task_struct and an interrupt will look into it after it has been freed. The fix is to stop passing a signal number into to_irq_stack. Rather, the pending signals mask is initialized beforehand with the bit for sig already set. References to sig in to_irq_stack can be replaced with references to the mask. [akpm@linux-foundation.org: use UL] 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>
2007-09-19uml: use correct type in BLKGETSIZE ioctlNicolas George
I found a type mismatch in UML that makes host block devices unusable as ubd devices on x86_64 and other 64 bits systems (segfault of the mm subsystem): In block/ioctl.c, the following lines show that the BLKGETSIZE ioctl expects a pointer to a long: case BLKGETSIZE: if ((bdev->bd_inode->i_size >> 9) > ~0UL) return -EFBIG; return put_ulong(arg, bdev->bd_inode->i_size >> 9); In arch/um/os-Linux/file.c, os_file_size calls it with an int. The ioctl_list man page should be fixed as well. Cc: Jeff Dike <jdike@addtoit.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-08-31uml: fix x86_64 core dump crashJeff Dike
Stop UML crashing when trying to dump a process core on x86_64. This is the minimal fix to stop the crash - more things are broken here, and patches are forthcoming. The immediate thing to do is define ELF_CORE_COPY_REGS and ELF_CORE_COPY_FPREGS. Defining ELF_CORE_COPY_FPREGS allows dump_fpu to go away. It is defined in terms of save_fp_registers, so that needs to be added. 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>
2007-07-24uml: more __init annotationsJeff Dike
2.6.23-rc1 turned up another batch of references from non-__init code to __init code. In most cases, these were missing __init annotations. In one case (os_drop_memory), the annotation was present but wrong. init_maps is __init, but for some reason was being very careful about the mechanism by which it allocated memory, checking whether it was OK to use kmalloc (at this point in the boot, it definitely isn't) and using either alloc_bootmem_low_pages or kmalloc/vmalloc. So, the kmalloc/vmalloc code is removed. 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>
2007-07-24uml: fix aio compilation bugJeff Dike
Restructure do_aio thanks to commments from Ulrich and Al. Uli started this by seeing that UML's initialization of a struct iocb initialized fields that it shouldn't. Al followed up by adding the following cleanups: eliminating a variable by just using an anonymous structure in its place. hoisting a duplicated line out of the switch. simplifying the error checking at the end. I added a severity to the printk. Signed-off-by: Jeff Dike <jdike@linux.intel.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Ulrich Drepper <drepper@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-07-24uml: fix string exporting on UML/i386Jeff Dike
In 2.6.23-rc1, i386 fiddled its string support such that UML started getting undefined references from modules. The UML asm/string.h was including the i386 string.h, which defined __HAVE_ARCH_STR*, but the corresponding implementations weren't being pulled in. This is fixed by adding arch/i386/lib/string.h to the list of host architecture files to be pulled in to UML. A complication is that the libc exports file assumed that the generic strlen and strstr weren't in use (i.e. __HAVE_ARCH_STR is defined), then they aren't exported. This is untrue for strlen, which is exported in either case, so this logic is not needed. 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>
2007-07-16uml: export hostfs symbolsJeff Dike
Add some exports for hostfs that are required after Alberto Bertogli's fixes for accessing unlinked host files. Also did some style cleanups while I was here. Signed-off-by: Jeff Dike <jdike@linux.intel.com> Cc: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-07-16uml: Eliminate kernel allocator wrappersJeff Dike
UML had two wrapper procedures for kmalloc, um_kmalloc and um_kmalloc_atomic because the flag constants weren't available in userspace code. kern_constants.h had made kernel constants available for a long time, so there is no need for these wrappers any more. Rather, userspace code calls kmalloc directly with the userspace versions of the gfp flags. kmalloc isn't a real procedure, so I had to essentially copy the inline wrapper around __kmalloc. vmalloc also had its own wrapper for no good reason. This is now gone. Signed-off-by: Jeff Dike <jdike@linux.intel.com> Cc: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-07-16uml: simplify helper stack handlingJeff Dike
run_helper and run_helper_thread had arguments which were the same in all callers. run_helper's stack_out was always NULL and run_helper_thread's stack_order was always 0. These are now gone, and the constants folded into the code. Also fixed leaks of the helper stack in the AIO and SIGIO code. 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>
2007-07-16uml: SIGIO support cleanupJeff Dike
Cleanup of the SIGWINCH support. Some code and comment reformatting. The stack used for SIGWINCH threads was leaked. This is now fixed by storing it with the pid and other information, and freeing it when the thread is killed. If something goes wrong with a WIGWINCH thread, and this is discovered in the interrupt handler, the winch record would leak. It is now freed, except that the IRQ isn't freed. This is hard to do from interrupt context. This has the side-effect that the IRQ system maintains a reference to the freed structure, but that shouldn't cause a problem since the descriptor is disabled. register_winch_irq is now much better about cleaning up after an initialization failure. Signed-off-by: Jeff Dike <jdike@linux.intel.com> Cc: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-06-16uml: remove PAGE_SIZE from libc codeJeff Dike
Distros seem to be removing PAGE_SIZE from asm/page.h. So, the libc side of UML should stop using it. I replace it with UM_KERN_PAGE_SIZE, which is defined to be the same as PAGE_SIZE on the kernel side of the house. I could also use getpagesize(), but it's more important that UML have the same value of PAGE_SIZE everywhere. It's conceivable that it could be built with a larger PAGE_SIZE, and use of getpagesize() would break that badly. PAGE_MASK got the same treatment, as it is closely tied to PAGE_SIZE. 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>
2007-05-23uml: improve PTRACE_SYSEMU checkingJeff Dike
Make the PTRACE_SYSEMU checking more robust. It will make sure that system call numbers are reported correctly. If there is a problem, it will disable PTRACE_SYSEMU use and use PTRACE_SYSCALL instead. Thanks to Balaji G for helping reproduce this problem. 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>
2007-05-11uml: iRQ stacksJeff Dike
Add a separate IRQ stack. This differs from i386 in having the entire interrupt run on a separate stack rather than starting on the normal kernel stack and switching over once some preparation has been done. The underlying mechanism, is of course, sigaltstack. Another difference is that interrupts that happen in userspace are handled on the normal kernel stack. These cause a wait wakeup instead of a signal delivery so there is no point in trying to switch stacks for these. There's no other stuff on the stack, so there is no extra stack consumption. This quirk makes it possible to have the entire interrupt run on a separate stack - process preemption (and calls to schedule()) happens on a normal kernel stack. If we enable CONFIG_PREEMPT, this will need to be rethought. The IRQ stack for CPU 0 is declared in the same way as the initial kernel stack. IRQ stacks for other CPUs will be allocated dynamically. An extra field was added to the thread_info structure. When the active thread_info is copied to the IRQ stack, the real_thread field points back to the original stack. This makes it easy to tell where to copy the thread_info struct back to when the interrupt is finished. It also serves as a marker of a nested interrupt. It is NULL for the first interrupt on the stack, and non-NULL for any nested interrupts. Care is taken to behave correctly if a second interrupt comes in when the thread_info structure is being set up or taken down. I could just disable interrupts here, but I don't feel like giving up any of the performance gained by not flipping signals on and off. If an interrupt comes in during these critical periods, the handler can't run because it has no idea what shape the stack is in. So, it sets a bit for its signal in a global mask and returns. The outer handler will deal with this signal itself. Atomicity is had with xchg. A nested interrupt that needs to bail out will xchg its signal mask into pending_mask and repeat in case yet another interrupt hit at the same time, until the mask stabilizes. The outermost interrupt will set up the thread_info and xchg a zero into pending_mask when it is done. At this point, nested interrupts will look at ->real_thread and see that no setup needs to be done. They can just continue normally. Similar care needs to be taken when exiting the outer handler. If another interrupt comes in while it is copying the thread_info, it will drop a bit into pending_mask. The outer handler will check this and if it is non-zero, will loop, set up the stack again, and handle the interrupt. Signed-off-by: Jeff Dike <jdike@linux.intel.com> Cc: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-05-11uml: tidy IRQ codeJeff Dike
Some tidying of the irq code before introducing irq stacks. Mostly style fixes, but the timer handler calls the timer code directly rather than going through the generic sig_handler_common_skas. Signed-off-by: Jeff Dike <jdike@linux.intel.com> Cc: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-05-11uml: use UM_THREAD_SIZE in userspace codeJeff Dike
Now that we have UM_THREAD_SIZE, we can replace the calculations in user-space code (an earlier patch took care of the kernel side of the house). Signed-off-by: Jeff Dike <jdike@linux.intel.com> Cc: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-05-11uml: remove task_protectionsJeff Dike
Replaced task_protections with stack_protections since they do the same thing, and task_protections was misnamed anyway. This needs THREAD_SIZE, so that's imported via common-offsets.h Also tidied up the code in the vicinity. Signed-off-by: Jeff Dike <jdike@linux.intel.com> Cc: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-05-09uml: turn build warnings into commentsMiklos Szeredi
These haven't been fixed for ages. Just make comments out of them. arch/um/kernel/skas/process.c:181:2: warning: #warning Need to look up +userspace_pid by cpu arch/um/kernel/skas/process.c:187:2: warning: #warning Need to look up +userspace_pid by cpu arch/um/kernel/skas/process.c:194:2: warning: #warning need to loop over +userspace_pids in kill_off_processes_skas Signed-off-by: Miklos Szeredi <mszeredi@suse.cz> Signed-off-by: Jeff Dike <jdike@linux.intel.com> Cc: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-05-09uml: mark a tt-only functionJeff Dike
Mark another function as tt-mode only. Signed-off-by: Jeff Dike <jdike@linux.intel.com> Cc: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-05-07uml: more page fault path trimmingJeff Dike
More trimming of the page fault path. Permissions are passed around in a single int rather than one bit per int. The permission values are copied from libc so that they can be passed to mmap and mprotect without any further conversion. The register sets used by do_syscall_stub and copy_context_skas0 are initialized once, at boot time, rather than once per call. wait_stub_done checks whether it is getting the signals it expects by comparing the wait status to a mask containing bits for the signals of interest rather than comparing individually to the signal numbers. It also has one check for a wait failure instead of two. The caller is expected to do the initial continue of the stub. This gets rid of an argument and some logic. The fname argument is gone, as that can be had from a stack trace. user_signal() is collapsed into userspace() as it is basically one or two lines of code afterwards. The physical memory remapping stuff is gone, as it is unused. flush_tlb_page is inlined. Signed-off-by: Jeff Dike <jdike@linux.intel.com> Cc: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-05-07uml: speed page fault pathJeff Dike
Give the page fault code a specialized path. There is only one page to look at, so there's no point in going into the general page table walking code. There's only going to be one host operation, so there are no opportunities for merging. So, we go straight to the pte we want, figure out what needs doing, and do it. While I was in here, I fixed the wart where the address passed to unmap was a void *, but an unsigned long to map and protect. This gives me just under 10% on a kernel build. Signed-off-by: Jeff Dike <jdike@linux.intel.com> Cc: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-05-07uml: aIO deadlock avoidanceJeff Dike
Allow deadlocks to be avoided in the AIO code by setting the pipe to the I/O thread non-blocking. Signed-off-by: Jeff Dike <jdike@linux.intel.com> Cc: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-05-07uml: rename os_{read_write}_file_k back to os_{read_write}_fileJeff Dike
Rename os_{read_write}_file_k back to os_{read_write}_file, delete the originals and their bogus infrastructure, and fix all the callers. Signed-off-by: Jeff Dike <jdike@linux.intel.com> Cc: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-05-07uml: don't try to handle signals on initial process stackJeff Dike
Code running on the initial UML stack can't receive or process signals since current must be valid when IRQs are handled, and there is no current for this stack. So, instead of using UML_LONGJMP and UML_SETJMP, which are careful to save and restore signal state, and, as a side-effect, handle any deferred signals, start_idle_thread must use the bare equivalents, which don't do anything with signals. Signed-off-by: Jeff Dike <jdike@linux.intel.com> Cc: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-05-07uml: dump core on panicJeff Dike
Dump core after a panic. This will provide better debugging information than is currently available. Signed-off-by: Jeff Dike <jdike@linux.intel.com> Cc: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-05-07uml: convert libc layer to call read and writeJeff Dike
This patch converts calls in the os layer to os_{read,write}_file to calls directly to libc read() and write() where it is clear that the I/O buffer is in the kernel. We can do that here instead of calling os_{read,write}_file_k since we are in libc code and can call libc directly. With the change in the calls, error handling needs to be changed to refer to errno directly rather than the return value of the call. CATCH_EINTR wrappers were also added where needed. Signed-off-by: Jeff Dike <jdike@linux.intel.com> Cc: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-05-07uml: tidy libc codeJeff Dike
This patch lays some groundwork for the next one, which converts calls to os_{read,write}_file into {read,write}, by doing some tidying in the affected areas. do_not_aio gets restructured to make the final result a bit cleaner. There are also whitespace and other formatting fixes, fixes in error messages, and a typo fix. Signed-off-by: Jeff Dike <jdike@linux.intel.com> Cc: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-05-07uml: start fixing os_read_file and os_write_fileJeff Dike
This patch starts the removal of a very old, very broken piece of code. This stems from the problem of passing a userspace buffer into read() or write() on the host. If that buffer had not yet been faulted in, read and write will return -EFAULT. To avoid this problem, the solution was to fault the buffer in before the system call by touching the pages that hold the buffer by doing a copy-user of a byte to each page. This is obviously bogus, but it does usually work, in tt mode, since the kernel and process are in the same address space and userspace addresses can be accessed directly in the kernel. In skas mode, where the kernel and process are in separate address spaces, it is completely bogus because the userspace address, which is invalid in the kernel, is passed into the system call instead of the corresponding physical address, which would be valid. Here, it appears that this code, on every host read() or write(), tries to fault in a random process page. This doesn't seem to cause any correctness problems, but there is a performance impact. This patch, and the ones following, result in a 10-15% performance gain on a kernel build. This code can't be immediately tossed out because when it is, you can't log in. Apparently, there is some code in the console driver which depends on this somehow. However, we can start removing it by switching the code which does I/O using kernel addresses to using plain read() and write(). This patch introduces os_read_file_k and os_write_file_k for use with kernel buffers and converts all call locations which use obvious kernel buffers to use them. These include I/O using buffers which are local variables which are on the stack or kmalloc-ed. Later patches will handle the less obvious cases, followed by a mass conversion back to the original interface. Signed-off-by: Jeff Dike <jdike@linux.intel.com> Cc: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>