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* x86, vm86: Fix preemption bug for int1 debug and int3 breakpoint handlers.Bart Oldeman2010-09-231-2/+8
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Impact: fix kernel bug such as: BUG: scheduling while atomic: dosemu.bin/19680/0x00000004 See also Ubuntu bug 455067 at https://bugs.launchpad.net/ubuntu/+source/linux/+bug/455067 Commits 4915a35e35a037254550a2ba9f367a812bc37d40 ("Use preempt_conditional_sti/cli in do_int3, like on x86_64.") and 3d2a71a596bd9c761c8487a2178e95f8a61da083 ("x86, traps: converge do_debug handlers") started disabling preemption in int1 and int3 handlers on i386. The problem with vm86 is that the call to handle_vm86_trap() may jump straight to entry_32.S and never returns so preempt is never enabled again, and there is an imbalance in the preempt count. Commit be716615fe596ee117292dc615e95f707fb67fd1 ("x86, vm86: fix preemption bug"), which was later (accidentally?) reverted by commit 08d68323d1f0c34452e614263b212ca556dae47f ("hw-breakpoints: modifying generic debug exception to use thread-specific debug registers") fixed the problem for debug exceptions but not for breakpoints. There are three solutions to this problem. 1. Reenable preemption before calling handle_vm86_trap(). This was the approach that was later reverted. 2. Do not disable preemption for i386 in breakpoint and debug handlers. This was the situation before October 2008. As far as I understand preemption only needs to be disabled on x86_64 because a seperate stack is used, but it's nice to have things work the same way on i386 and x86_64. 3. Let handle_vm86_trap() return instead of jumping to assembly code. By setting a flag in _TIF_WORK_MASK, either TIF_IRET or TIF_NOTIFY_RESUME, the code in entry_32.S is instructed to return to 32 bit mode from V86 mode. The logic in entry_32.S was already present to handle signals. (I chose TIF_IRET because it's slightly more efficient in do_notify_resume() in signal.c, but in fact TIF_IRET can probably be replaced by TIF_NOTIFY_RESUME everywhere.) I'm submitting approach 3, because I believe it is the most elegant and prevents future confusion. Still, an obvious preempt_conditional_cli(regs); is necessary in traps.c to correct the bug. [ hpa: This is technically a regression, but because: 1. the regression is so old, 2. the patch seems relatively high risk, justifying more testing, and 3. we're late in the 2.6.36-rc cycle, I'm queuing it up for the 2.6.37 merge window. It might, however, justify as a -stable backport at a latter time, hence Cc: stable. ] Signed-off-by: Bart Oldeman <bartoldeman@users.sourceforge.net> LKML-Reference: <alpine.DEB.2.00.1009231312330.4732@localhost.localdomain> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: K.Prasad <prasad@linux.vnet.ibm.com> Cc: Alan Stern <stern@rowland.harvard.edu> Cc: Alexander van Heukelum <heukelum@fastmail.fm> Cc: <stable@kernel.org> Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
* x86, 32-bit: Convert sys_vm86 & sys_vm86oldBrian Gerst2009-12-091-6/+5
| | | | | | | | Convert these to new PTREGSCALL stubs. Signed-off-by: Brian Gerst <brgerst@gmail.com> LKML-Reference: <1260403316-5679-6-git-send-email-brgerst@gmail.com> Signed-off-by: H. Peter Anvin <hpa@zytor.com>
* Merge branch 'x86-urgent-for-linus' of ↵Linus Torvalds2009-06-101-4/+5
|\ | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip * 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: x86: Clear TS in irq_ts_save() when in an atomic section x86: Detect use of extended APIC ID for AMD CPUs x86: memtest: remove 64-bit division x86, UV: Fix macros for multiple coherency domains x86: Fix non-lazy GS handling in sys_vm86() x86: Add quirk for reboot stalls on a Dell Optiplex 360 x86: Fix UV BAU activation descriptor init
| * x86: Fix non-lazy GS handling in sys_vm86()Lubomir Rintel2009-06-071-4/+5
| | | | | | | | | | | | | | | | | | | | | | | | | | | | This fixes a stack corruption panic or null dereference oops due to a bad GS in resume_userspace() when returning from sys_vm86() and calling lockdep_sys_exit(). Only a problem when CONFIG_LOCKDEP and CONFIG_CC_STACKPROTECTOR enabled. Signed-off-by: Lubomir Rintel <lkundrak@v3.sk> Cc: H. Peter Anvin <hpa@zytor.com> LKML-Reference: <1244384628.2323.4.camel@bimbo> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* | x86: use symbolic name for VM86_SIGNAL when used as vm86 default returnSamuel Bronson2009-05-061-2/+2
|/ | | | | | | | | | | | | | | This code has apparently used "0" and not VM86_SIGNAL since Linux 1.1.9, when Linus added VM86_SIGNAL to vm86.h. This patch changes the code to use the symbolic name. The magic 0 tripped me up in trying to extend the vm86(2) manpage to actually explain vm86()'s interface -- my greps for VM86_SIGNAL came up fruitless. [ Impact: cleanup; no object code change ] Signed-off-by: Samuel Bronson <naesten@gmail.com> Signed-off-by: H. Peter Anvin <hpa@zytor.com>
* x86: use regparm(3) for passed-in pt_regs pointerBrian Gerst2009-02-111-5/+6
| | | | | | | | | | | | | | | Some syscalls need to access the pt_regs structure, either to copy user register state or to modifiy it. This patch adds stubs to load the address of the pt_regs struct into the %eax register, and changes the syscalls to take the pointer as an argument instead of relying on the assumption that the pt_regs structure overlaps the function arguments. Drop the use of regparm(1) due to concern about gcc bugs, and to move in the direction of the eventual removal of regparm(0) for asmlinkage. Signed-off-by: Brian Gerst <brgerst@gmail.com> Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
* x86: pass in pt_regs pointer for syscalls that need itBrian Gerst2009-02-111-8/+7
| | | | | | | | | | | | Some syscalls need to access the pt_regs structure, either to copy user register state or to modifiy it. This patch adds stubs to load the address of the pt_regs struct into the %eax register, and changes the syscalls to regparm(1) to receive the pt_regs pointer as the first argument. Signed-off-by: Brian Gerst <brgerst@gmail.com> Acked-by: Tejun Heo <tj@kernel.org> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* x86: add %gs accessors for x86_32Tejun Heo2009-02-101-2/+2
| | | | | | | | | | | | | | | | | Impact: cleanup On x86_32, %gs is handled lazily. It's not saved and restored on kernel entry/exit but only when necessary which usually is during task switch but there are few other places. Currently, it's done by calling savesegment() and loadsegment() explicitly. Define get_user_gs(), set_user_gs() and task_user_gs() and use them instead. While at it, clean up register access macros in signal.c. This cleans up code a bit and will help future changes. Signed-off-by: Tejun Heo <tj@kernel.org> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* x86: Introducing asm/syscalls.hJaswinder Singh2008-07-221-0/+1
| | | | | | Declaring arch-dependent syscalls for x86 architecture Signed-off-by: Jaswinder Singh <jaswinder@infradead.org>
* x86: replace most VM86 flags with flags from processor-flags.hgorcunov@gmail.com2008-04-171-17/+17
| | | | | Signed-off-by: Cyrill Gorcunov <gorcunov@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* x86: cleanup - rename VM_MASK to X86_VM_MASKgorcunov@gmail.com2008-04-171-1/+1
| | | | | | | | | | | This patch renames VM_MASK to X86_VM_MASK (which in turn defined as alias to X86_EFLAGS_VM) to better distinguish from virtual memory flags. We can't just use X86_EFLAGS_VM instead because it is also used for conditional compilation Signed-off-by: Cyrill Gorcunov <gorcunov@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* x86: handle_vm86_trap cleanupRoland McGrath2008-04-171-8/+1
| | | | | | | Use force_sig in handle_vm86_trap like other machine traps do. Signed-off-by: Roland McGrath <roland@redhat.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* x86: coding style fixes to arch/x86/kernel/vm86_32.cPaolo Ciarrocchi2008-04-171-85/+89
| | | | | | | | | | | | | | | | | | | | | | Before: total: 64 errors, 18 warnings, 840 lines checked After: total: 12 errors, 15 warnings, 844 lines checked No code changed: arch/x86/kernel/vm86_32.o: text data bss dec hex filename 4449 28 132 4609 1201 vm86_32.o.before 4449 28 132 4609 1201 vm86_32.o.after md5: e4e51ed7689d17f04148554a3c6d5bb6 vm86_32.o.before.asm e4e51ed7689d17f04148554a3c6d5bb6 vm86_32.o.after.asm Signed-off-by: Paolo Ciarrocchi <paolo.ciarrocchi@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* arch/x86/: spelling fixesJoe Perches2008-01-301-1/+1
| | | | | | | | Spelling fixes. Signed-off-by: Joe Perches <joe@perches.com> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
* x86: remove all definitions with fastcallHarvey Harrison2008-01-301-2/+1
| | | | | | | | fastcall is always defined to be empty, remove it from arch/x86 Signed-off-by: Harvey Harrison <harvey.harrison@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
* x86: remove last users of FASTCALLHarvey Harrison2008-01-301-1/+1
| | | | | | | | FASTCALL() is always empty. Signed-off-by: Harvey Harrison <harvey.harrison@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
* x86: use generic register name in the thread and tss structuresH. Peter Anvin2008-01-301-8/+8
| | | | | | | | | This changes size-specific register names (eip/rip, esp/rsp, etc.) to generic names in the thread and tss structures. Signed-off-by: H. Peter Anvin <hpa@zytor.com> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
* x86: rename the struct pt_regs members for 32/64-bit consistencyH. Peter Anvin2008-01-301-47/+47
| | | | | | | | | | | | | | | We have a lot of code which differs only by the naming of specific members of structures that contain registers. In order to enable additional unifications, this patch drops the e- or r- size prefix from the register names in struct pt_regs, and drops the x- prefixes for segment registers on the 32-bit side. This patch also performs the equivalent renames in some additional places that might be candidates for unification in the future. Signed-off-by: H. Peter Anvin <hpa@zytor.com> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
* Delete filenames in comments.Dave Jones2007-10-131-2/+0
| | | | | | | | | | | | | | | Since the x86 merge, lots of files that referenced their own filenames are no longer correct. Rather than keep them up to date, just delete them, as they add no real value. Additionally: - fix up comment formatting in scx200_32.c - Remove a credit from myself in setup_64.c from a time when we had no SCM - remove longwinded history from tsc_32.c which can be figured out from git. Signed-off-by: Dave Jones <davej@redhat.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* i386: move kernelThomas Gleixner2007-10-111-0/+843
Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Ingo Molnar <mingo@elte.hu>
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