aboutsummaryrefslogtreecommitdiffstats
path: root/arch/x86/lib
Commit message (Collapse)AuthorAge
* x86: use early clobbers in usercopy*.cAndi Kleen2009-01-21
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Impact: fix rare (but currently harmless) miscompile with certain configs and gcc versions Hugh Dickins noticed that strncpy_from_user() was miscompiled in some circumstances with gcc 4.3. Thanks to Hugh's excellent analysis it was easy to track down. Hugh writes: > Try building an x86_64 defconfig 2.6.29-rc1 kernel tree, > except not quite defconfig, switch CONFIG_PREEMPT_NONE=y > and CONFIG_PREEMPT_VOLUNTARY off (because it expands a > might_fault() there, which hides the issue): using a > gcc 4.3.2 (I've checked both openSUSE 11.1 and Fedora 10). > > It generates the following: > > 0000000000000000 <__strncpy_from_user>: > 0: 48 89 d1 mov %rdx,%rcx > 3: 48 85 c9 test %rcx,%rcx > 6: 74 0e je 16 <__strncpy_from_user+0x16> > 8: ac lods %ds:(%rsi),%al > 9: aa stos %al,%es:(%rdi) > a: 84 c0 test %al,%al > c: 74 05 je 13 <__strncpy_from_user+0x13> > e: 48 ff c9 dec %rcx > 11: 75 f5 jne 8 <__strncpy_from_user+0x8> > 13: 48 29 c9 sub %rcx,%rcx > 16: 48 89 c8 mov %rcx,%rax > 19: c3 retq > > Observe that "sub %rcx,%rcx; mov %rcx,%rax", whereas gcc 4.2.1 > (and many other configs) say "sub %rcx,%rdx; mov %rdx,%rax". > Isn't it returning 0 when it ought to be returning strlen? The asm constraints for the strncpy_from_user() result were missing an early clobber, which tells gcc that the last output arguments are written before all input arguments are read. Also add more early clobbers in the rest of the file and fix 32-bit usercopy.c in the same way. Signed-off-by: Andi Kleen <ak@linux.intel.com> Signed-off-by: H. Peter Anvin <hpa@zytor.com> [ since this API is rarely used and no in-kernel user relies on a 'len' return value (they only rely on negative return values) this miscompile was never noticed in the field. But it's worth fixing it nevertheless. ] Signed-off-by: Ingo Molnar <mingo@elte.hu>
* Merge commit 'v2.6.28-rc2' into core/lockingIngo Molnar2008-10-28
|\ | | | | | | | | Conflicts: arch/um/include/asm/system.h
| * Merge branch 'x86/unify-cpu-detect' into x86-v28-for-linus-phase4-DIngo Molnar2008-10-11
| |\ | | | | | | | | | | | | | | | | | | Conflicts: arch/x86/kernel/cpu/common.c arch/x86/kernel/signal_64.c include/asm-x86/cpufeature.h
| | * x86: drop -funroll-loops for csum_partial_64.cAndi Kleen2008-09-04
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Impact: performance optimization I did some rebenchmarking with modern compilers and dropping -funroll-loops makes the function consistently go faster by a few percent. So drop that flag. Thanks to Richard Guenther for a hint. Signed-off-by: Andi Kleen <ak@linux.intel.com> Signed-off-by: H. Peter Anvin <hpa@zytor.com>
| | * Merge branch 'x86/urgent' into x86/cpuH. Peter Anvin2008-08-27
| | |\ | | | | | | | | | | | | | | | | | | | | Conflicts: arch/x86/kernel/cpu/cyrix.c
| | * | x86: make movsl_mask definition non-CPU specificThomas Petazzoni2008-08-18
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | movsl_mask is currently defined in arch/x86/kernel/cpu/intel.c, which contains code specific to Intel CPUs. However, movsl_mask is used in the non-CPU specific code in arch/x86/lib/usercopy_32.c, which breaks the compilation when support for Intel CPUs is compiled out. This patch solves this problem by moving movsl_mask's definition close to its users in arch/x86/lib/usercopy_32.c. Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com> Cc: michael@free-electrons.com Signed-off-by: Ingo Molnar <mingo@elte.hu>
| * | | x86: msr-on-cpu: remove unnecessary level of abstractionH. Peter Anvin2008-08-26
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Remove an unnecessary level of abstraction in the msr-on-cpu library. Although this duplicates some code, the duplicated code is less than the additional code, and this way should be faster. Additionally, change the order of the functions to make the regular structure of this file more obvious. Signed-off-by: H. Peter Anvin <hpa@zytor.com>
| * | | Merge branch 'x86/urgent' into x86/cleanupsH. Peter Anvin2008-08-26
| |\ \ \ | | | |/ | | |/|
| * | | x86: coding style fixes to arch/x86/lib/string_32.cPaolo Ciarrocchi2008-08-15
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Before: total: 21 errors, 0 warnings, 237 lines checked After: total: 0 errors, 0 warnings, 237 lines checked paolo@paolo-desktop:~/linux.trees.git$ md5sum /tmp/string_32.o.* c55d059ef1612b32a8bb2771a72ae0d5 /tmp/string_32.o.after c55d059ef1612b32a8bb2771a72ae0d5 /tmp/string_32.o.before Signed-off-by: Paolo Ciarrocchi <paolo.ciarrocchi@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
| * | | x86: coding style fixes to arch/x86/lib/strstr_32.cPaolo Ciarrocchi2008-08-15
| | |/ | |/| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Before: total: 3 errors, 0 warnings, 31 lines checked After: total: 0 errors, 0 warnings, 31 lines checked paolo@paolo-desktop:~/linux.trees.git$ md5sum /tmp/strstr_32.o.* c96006ec3387862e5bacb139207a3098 /tmp/strstr_32.o.after c96006ec3387862e5bacb139207a3098 /tmp/strstr_32.o.before Signed-off-by: Paolo Ciarrocchi <paolo.ciarrocchi@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* | | x86: some lock annotations for user copy paths, v3Ingo Molnar2008-09-11
| | | | | | | | | | | | | | | | | | | | | - add annotation back to clear_user() - change probe_kernel_address() to _inatomic*() method Signed-off-by: Ingo Molnar <mingo@elte.hu>
* | | x86: some lock annotations for user copy paths, v2Nick Piggin2008-09-11
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | - introduce might_fault() - handle the atomic user copy paths correctly [ mingo@elte.hu: move might_sleep() outside of in_atomic(). ] Signed-off-by: Nick Piggin <npiggin@suse.de> Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* | | x86: some lock annotations for user copy pathsNick Piggin2008-09-10
| |/ |/| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | copy_to/from_user and all its variants (except the atomic ones) can take a page fault and perform non-trivial work like taking mmap_sem and entering the filesyste/pagecache. Unfortunately, this often escapes lockdep because a common pattern is to use it to read in some arguments just set up from userspace, or write data back to a hot buffer. In those cases, it will be unlikely for page reclaim to get a window in to cause copy_*_user to fault. With the new might_lock primitives, add some annotations to x86. I don't know if I caught all possible faulting points (it's a bit of a maze, and I didn't really look at 32-bit). But this is a starting point. Boots and runs OK so far. Signed-off-by: Nick Piggin <npiggin@suse.de> Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* | x86: msr: propagate errors from smp_call_function_single()H. Peter Anvin2008-08-25
|/ | | | | | | | Propagate error (-ENXIO) from smp_call_function_single(). These errors can happen when a CPU is unplugged while the MSR driver is open. Signed-off-by: H. Peter Anvin <hpa@zytor.com>
* x86: wrong register was used in align macroVitaly Mayatskikh2008-07-30
| | | | | | | | | | | New ALIGN_DESTINATION macro has sad typo: r8d register was used instead of ecx in fixup section. This can be considered as a regression. Register ecx was also wrongly loaded with value in r8d in copy_user_nocache routine. Signed-off-by: Vitaly Mayatskikh <v.mayatskih@gmail.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* Merge branch 'generic-ipi' into generic-ipi-for-linusIngo Molnar2008-07-15
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Conflicts: arch/powerpc/Kconfig arch/s390/kernel/time.c arch/x86/kernel/apic_32.c arch/x86/kernel/cpu/perfctr-watchdog.c arch/x86/kernel/i8259_64.c arch/x86/kernel/ldt.c arch/x86/kernel/nmi_64.c arch/x86/kernel/smpboot.c arch/x86/xen/smp.c include/asm-x86/hw_irq_32.h include/asm-x86/hw_irq_64.h include/asm-x86/mach-default/irq_vectors.h include/asm-x86/mach-voyager/irq_vectors.h include/asm-x86/smp.h kernel/Makefile Signed-off-by: Ingo Molnar <mingo@elte.hu>
| * smp_call_function: get rid of the unused nonatomic/retry argumentJens Axboe2008-06-26
| | | | | | | | | | | | | | | | It's never used and the comments refer to nonatomic and retry interchangably. So get rid of it. Acked-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
* | Merge branch 'auto-ftrace-next' into tracing/for-linusIngo Molnar2008-07-14
|\ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Conflicts: arch/x86/kernel/entry_32.S arch/x86/kernel/process_32.c arch/x86/kernel/process_64.c arch/x86/lib/Makefile include/asm-x86/irqflags.h kernel/Makefile kernel/sched.c Signed-off-by: Ingo Molnar <mingo@elte.hu>
| * | Merge branch 'linus' into tracing/ftraceIngo Molnar2008-06-23
| |\|
| * | Merge branch 'linus' into tracing/ftraceIngo Molnar2008-06-16
| |\ \
| * | | ftrace: trace irq disabled critical timingsSteven Rostedt2008-05-23
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This patch adds latency tracing for critical timings (how long interrupts are disabled for). "irqsoff" is added to /debugfs/tracing/available_tracers Note: tracing_max_latency also holds the max latency for irqsoff (in usecs). (default to large number so one must start latency tracing) tracing_thresh threshold (in usecs) to always print out if irqs off is detected to be longer than stated here. If irq_thresh is non-zero, then max_irq_latency is ignored. Here's an example of a trace with ftrace_enabled = 0 ======= preemption latency trace v1.1.5 on 2.6.24-rc7 Signed-off-by: Ingo Molnar <mingo@elte.hu> -------------------------------------------------------------------- latency: 100 us, #3/3, CPU#1 | (M:rt VP:0, KP:0, SP:0 HP:0 #P:2) ----------------- | task: swapper-0 (uid:0 nice:0 policy:0 rt_prio:0) ----------------- => started at: _spin_lock_irqsave+0x2a/0xb7 => ended at: _spin_unlock_irqrestore+0x32/0x5f _------=> CPU# / _-----=> irqs-off | / _----=> need-resched || / _---=> hardirq/softirq ||| / _--=> preempt-depth |||| / ||||| delay cmd pid ||||| time | caller \ / ||||| \ | / swapper-0 1d.s3 0us+: _spin_lock_irqsave+0x2a/0xb7 (e1000_update_stats+0x47/0x64c [e1000]) swapper-0 1d.s3 100us : _spin_unlock_irqrestore+0x32/0x5f (e1000_update_stats+0x641/0x64c [e1000]) swapper-0 1d.s3 100us : trace_hardirqs_on_caller+0x75/0x89 (_spin_unlock_irqrestore+0x32/0x5f) vim:ft=help ======= And this is a trace with ftrace_enabled == 1 ======= preemption latency trace v1.1.5 on 2.6.24-rc7 -------------------------------------------------------------------- latency: 102 us, #12/12, CPU#1 | (M:rt VP:0, KP:0, SP:0 HP:0 #P:2) ----------------- | task: swapper-0 (uid:0 nice:0 policy:0 rt_prio:0) ----------------- => started at: _spin_lock_irqsave+0x2a/0xb7 => ended at: _spin_unlock_irqrestore+0x32/0x5f _------=> CPU# / _-----=> irqs-off | / _----=> need-resched || / _---=> hardirq/softirq ||| / _--=> preempt-depth |||| / ||||| delay cmd pid ||||| time | caller \ / ||||| \ | / swapper-0 1dNs3 0us+: _spin_lock_irqsave+0x2a/0xb7 (e1000_update_stats+0x47/0x64c [e1000]) swapper-0 1dNs3 46us : e1000_read_phy_reg+0x16/0x225 [e1000] (e1000_update_stats+0x5e2/0x64c [e1000]) swapper-0 1dNs3 46us : e1000_swfw_sync_acquire+0x10/0x99 [e1000] (e1000_read_phy_reg+0x49/0x225 [e1000]) swapper-0 1dNs3 46us : e1000_get_hw_eeprom_semaphore+0x12/0xa6 [e1000] (e1000_swfw_sync_acquire+0x36/0x99 [e1000]) swapper-0 1dNs3 47us : __const_udelay+0x9/0x47 (e1000_read_phy_reg+0x116/0x225 [e1000]) swapper-0 1dNs3 47us+: __delay+0x9/0x50 (__const_udelay+0x45/0x47) swapper-0 1dNs3 97us : preempt_schedule+0xc/0x84 (__delay+0x4e/0x50) swapper-0 1dNs3 98us : e1000_swfw_sync_release+0xc/0x55 [e1000] (e1000_read_phy_reg+0x211/0x225 [e1000]) swapper-0 1dNs3 99us+: e1000_put_hw_eeprom_semaphore+0x9/0x35 [e1000] (e1000_swfw_sync_release+0x50/0x55 [e1000]) swapper-0 1dNs3 101us : _spin_unlock_irqrestore+0xe/0x5f (e1000_update_stats+0x641/0x64c [e1000]) swapper-0 1dNs3 102us : _spin_unlock_irqrestore+0x32/0x5f (e1000_update_stats+0x641/0x64c [e1000]) swapper-0 1dNs3 102us : trace_hardirqs_on_caller+0x75/0x89 (_spin_unlock_irqrestore+0x32/0x5f) vim:ft=help ======= Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
* | | | x86: fix compile error in current tip.gitJeremy Fitzhardinge2008-07-10
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Gas 2.15 complains about 32-bit registers being used in lea. AS arch/x86/lib/copy_user_64.o /local/scratch-2/jeremy/hg/xen/paravirt/linux/arch/x86/lib/copy_user_64.S: Assembler messages: /local/scratch-2/jeremy/hg/xen/paravirt/linux/arch/x86/lib/copy_user_64.S:188: Error: `(%edx,%ecx,8)' is not a valid 64 bit base/index expression /local/scratch-2/jeremy/hg/xen/paravirt/linux/arch/x86/lib/copy_user_64.S:257: Error: `(%edx,%ecx,8)' is not a valid 64 bit base/index expression AS arch/x86/lib/copy_user_nocache_64.o /local/scratch-2/jeremy/hg/xen/paravirt/linux/arch/x86/lib/copy_user_nocache_64.S: Assembler messages: /local/scratch-2/jeremy/hg/xen/paravirt/linux/arch/x86/lib/copy_user_nocache_64.S:107: Error: `(%edx,%ecx,8)' is not a valid 64 bit base/index expression Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com> Cc: Vitaly Mayatskikh <v.mayatskih@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* | | | x86: fix copy_user on x86Vitaly Mayatskikh2008-07-09
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Switch copy_user_generic_string(), copy_user_generic_unrolled() and __copy_user_nocache() from custom tail handlers to generic copy_user_tail_handle(). Signed-off-by: Vitaly Mayatskikh <v.mayatskih@gmail.com> Acked-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* | | | x86: introduce copy_user_handle_tail() routineVitaly Mayatskikh2008-07-09
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Introduce generic C routine for handling necessary tail operations after protection fault in copy_*_user on x86. Signed-off-by: Vitaly Mayatskikh <v.mayatskih@gmail.com> Acked-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* | | | x86: merge putuser asm functions.Glauber Costa2008-07-09
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | putuser_32.S and putuser_64.S are merged into putuser.S. Signed-off-by: Glauber Costa <gcosta@redhat.com> Signed-off-by: H. Peter Anvin <hpa@zytor.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* | | | x86: use macros from asm.h.Glauber Costa2008-07-09
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | In putuser_32.S and putuser_64.S, replace things like .quad, .long, and explicit references to [r|e]ax for the apropriate macros in asm/asm.h. Signed-off-by: Glauber Costa <gcosta@redhat.com> Signed-off-by: H. Peter Anvin <hpa@zytor.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* | | | x86: don't use word-size specifiers in putuser files.Glauber Costa2008-07-09
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Remove them where unambiguous. Signed-off-by: Glauber Costa <gcosta@redhat.com> Signed-off-by: H. Peter Anvin <hpa@zytor.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* | | | x86: replace function headers by macros.Glauber Costa2008-07-09
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | In putuser_64.S, do it the i386 way, and replace the code in beginning and end of functions with macros, since it's always the same thing. Save lines. Signed-off-by: Glauber Costa <gcosta@redhat.com> Signed-off-by: H. Peter Anvin <hpa@zytor.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* | | | x86: change testing logic in putuser_64.S.Glauber Costa2008-07-09
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Instead of operating over a register we need to put back into normal state afterwards (the memory position), just sub from rbx, which is trashed anyway. We can save a few instructions. Also, this is the i386 way. Signed-off-by: Glauber Costa <gcosta@redhat.com> Signed-off-by: H. Peter Anvin <hpa@zytor.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* | | | x86: pass argument to putuser_64 functions in ax register.Glauber Costa2008-07-09
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This is consistent with i386 usage. Signed-off-by: Glauber Costa <gcosta@redhat.com> Signed-off-by: H. Peter Anvin <hpa@zytor.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* | | | x86: clobber rbx in putuser_64.S.Glauber Costa2008-07-09
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Instead of clobbering r8, clobber rbx, which is the i386 way. Signed-off-by: Glauber Costa <gcosta@redhat.com> Signed-off-by: H. Peter Anvin <hpa@zytor.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* | | | x86: don't save ebx in putuser_32.S.Glauber Costa2008-07-09
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Clobber it in the inline asm macros, and let the compiler do this for us. Signed-off-by: Glauber Costa <gcosta@redhat.com> Signed-off-by: H. Peter Anvin <hpa@zytor.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* | | | x86: merge getuser asm functions.Glauber Costa2008-07-09
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | getuser_32.S and getuser_64.S are merged into getuser.S. Signed-off-by: Glauber Costa <gcosta@redhat.com> Signed-off-by: H. Peter Anvin <hpa@zytor.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* | | | x86: use _ASM_PTR instead of explicit word-size pointers.Glauber Costa2008-07-09
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Switch .long and .quad with _ASM_PTR in getuser*.S. Signed-off-by: Glauber Costa <gcosta@redhat.com> Signed-off-by: H. Peter Anvin <hpa@zytor.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* | | | x86: introduce __ASM_REG macro.Glauber Costa2008-07-09
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | There are situations in which the architecture wants to use the register that represents its word-size, whatever it is. For those, introduce __ASM_REG in asm.h, along with the first users _ASM_AX and _ASM_DX. They have users waiting for it, namely the getuser functions. Signed-off-by: Glauber Costa <gcosta@redhat.com> Signed-off-by: H. Peter Anvin <hpa@zytor.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* | | | x86: don't use word-size specifiers on getuser_64.Glauber Costa2008-07-09
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The instructions access registers, so the size is unambiguous. Signed-off-by: Glauber Costa <gcosta@redhat.com> Signed-off-by: H. Peter Anvin <hpa@zytor.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* | | | x86: rename threadinfo to TI.Glauber Costa2008-07-09
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This is for consistency with i386. Signed-off-by: Glauber Costa <gcosta@redhat.com> Signed-off-by: H. Peter Anvin <hpa@zytor.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* | | | x86: adapt x86_64 getuser functions.Glauber Costa2008-07-09
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Instead of doing a sub after the addition, use the offset directly at the memory operand of the mov instructions. This is the way i386 do. Signed-off-by: Glauber Costa <gcosta@redhat.com> Signed-off-by: H. Peter Anvin <hpa@zytor.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* | | | x86: don't use word-size specifiers.Glauber Costa2008-07-09
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Since the instructions refer to registers, they'll be able to figure it out. Signed-off-by: Glauber Costa <gcosta@redhat.com> Signed-off-by: H. Peter Anvin <hpa@zytor.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* | | | x86: don't clobber r8 nor use rcx.Glauber Costa2008-07-09
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | There's really no reason to clobber r8 or pass the address in rcx. We can safely use only two registers (which we already have to touch anyway) to do the job. Signed-off-by: Glauber Costa <gcosta@redhat.com> Signed-off-by: H. Peter Anvin <hpa@zytor.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* | | | x86: integrate delay functions.Glauber Costa2008-07-09
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | delay_32.c, delay_64.c are now equal, and are integrated into delay.c. Signed-off-by: Glauber Costa <gcosta@redhat.com> Signed-off-by: H. Peter Anvin <hpa@zytor.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* | | | x86: explicitly use edx in const delay function.Glauber Costa2008-07-09
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | For x86_64, we can't just use %0, as it would generate a mul against rdx, which is not really what we want (note the ">> 32" in x86_64 version). Using a u64 variable with a shift in i386 generates bad code, so the solution is to explicitly use %%edx in inline assembly for both. Signed-off-by: Glauber Costa <gcosta@redhat.com> Signed-off-by: H. Peter Anvin <hpa@zytor.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* | | | x86: use rdtscll in read_current_timer for i386.Glauber Costa2008-07-09
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This way we achieve the same code for both arches. Signed-off-by: Glauber Costa <gcosta@redhat.com> Signed-off-by: H. Peter Anvin <hpa@zytor.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* | | | x86: provide delay loop for x86_64.Glauber Costa2008-07-09
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This is for consistency with i386. We call use_tsc_delay() at tsc initialization for x86_64, so we'll be always using it. Signed-off-by: Glauber Costa <gcosta@redhat.com> Signed-off-by: H. Peter Anvin <hpa@zytor.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* | | | x86: don't use size specifiers.Glauber Costa2008-07-09
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Remove the "l" from inline asm at arch/x86/lib/delay_32.c. It is not needed. Signed-off-by: Glauber Costa <gcosta@redhat.com> Signed-off-by: H. Peter Anvin <hpa@zytor.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* | | | Merge branch 'linus' into x86/delayIngo Molnar2008-06-25
|\ \ \ \ | | |_|/ | |/| | | | | | | | | | | | | | | | | | | | | | Conflicts: arch/x86/kernel/tsc_32.c Signed-off-by: Ingo Molnar <mingo@elte.hu>
| * | | x86-64: Fix "bytes left to copy" return value for copy_from_user()Linus Torvalds2008-06-17
| | |/ | |/| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Most users by far do not care about the exact return value (they only really care about whether the copy succeeded in its entirety or not), but a few special core routines actually care deeply about exactly how many bytes were copied from user space. And the unrolled versions of the x86-64 user copy routines would sometimes report that it had copied more bytes than it actually had. Very few uses actually have partial copies to begin with, but to make this bug even harder to trigger, most x86 CPU's use the "rep string" instructions for normal user copies, and that version didn't have this issue. To make it even harder to hit, the one user of this that really cared about the return value (and used the uncached version of the copy that doesn't use the "rep string" instructions) was the generic write routine, which pre-populated its source, once more hiding the problem by avoiding the exception case that triggers the bug. In other words, very special thanks to Bron Gondwana who not only triggered this, but created a test-program to show it, and bisected the behavior down to commit 08291429cfa6258c4cd95d8833beb40f828b194e ("mm: fix pagecache write deadlocks") which changed the access pattern just enough that you can now trigger it with 'writev()' with multiple iovec's. That commit itself was not the cause of the bug, it just allowed all the stars to align just right that you could trigger the problem. [ Side note: this is just the minimal fix to make the copy routines (with __copy_from_user_inatomic_nocache as the particular version that was involved in showing this) have the right return values. We really should improve on the exceptional case further - to make the copy do a byte-accurate copy up to the exact page limit that causes it to fail. As it is, the callers have to do extra work to handle the limit case gracefully. ] Reported-by: Bron Gondwana <brong@fastmail.fm> Cc: Nick Piggin <npiggin@suse.de> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Andi Kleen <andi@firstfloor.org> Cc: Al Viro <viro@ZenIV.linux.org.uk> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> (which didn't have this problem), and since most users that do the carethis was very hard to trigger, but
* / | x86: fix bug in arch/i386/lib/delay.c file, delay_loop functionJiri Hladky2008-06-17
|/ / | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | when trying to understand how Bogomips are implemented I have found a bug in arch/i386/lib/delay.c file, delay_loop function. The function fails for loops > 2^31+1. It because SF is set when dec returns numbers > 2^31. The fix is to use jnz instruction instead of jns (and add one decl instruction to the end to have exactly the same number of loops as in original version). Martin Mares observed: > It is a long time since I have hacked that file, but you should definitely > make sure that the function is never called with a zero argument. In such > case, the original version made just a single pass, but your version > makes 2^32 of them. fixed that. Signed-off-by: Ingo Molnar <mingo@elte.hu>
* / x86: enable preemption in delaySteven Rostedt2008-06-04
|/ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The RT team has been searching for a nasty latency. This latency shows up out of the blue and has been seen to be as big as 5ms! Using ftrace I found the cause of the latency. pcscd-2995 3dNh1 52360300us : irq_exit (smp_apic_timer_interrupt) pcscd-2995 3dN.2 52360301us : idle_cpu (irq_exit) pcscd-2995 3dN.2 52360301us : rcu_irq_exit (irq_exit) pcscd-2995 3dN.1 52360771us : smp_apic_timer_interrupt (apic_timer_interrupt ) pcscd-2995 3dN.1 52360771us : exit_idle (smp_apic_timer_interrupt) Here's an example of a 400 us latency. pcscd took a timer interrupt and returned with "need resched" enabled, but did not reschedule until after the next interrupt came in at 52360771us 400us later! At first I thought we somehow missed a preemption check in entry.S. But I also noticed that this always seemed to happen during a __delay call. pcscd-2995 3dN.2 52360836us : rcu_irq_exit (irq_exit) pcscd-2995 3.N.. 52361265us : preempt_schedule (__delay) Looking at the x86 delay, I found my problem. In git commit 35d5d08a085c56f153458c3f5d8ce24123617faf, Andrew Morton placed preempt_disable around the entire delay due to TSC's not working nicely on SMP. Unfortunately for those that care about latencies this is devastating! Especially when we have callers to mdelay(8). Here I enable preemption during the loop and account for anytime the task migrates to a new CPU. The delay asked for may be extended a bit by the migration, but delay only guarantees that it will delay for that minimum time. Delaying longer should not be an issue. [ Thanks to Thomas Gleixner for spotting that cpu wasn't updated, and to place the rep_nop between preempt_enabled/disable. ] Signed-off-by: Steven Rostedt <srostedt@redhat.com> Cc: akpm@osdl.org Cc: Clark Williams <clark.williams@gmail.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: "Luis Claudio R. Goncalves" <lclaudio@uudg.org> Cc: Gregory Haskins <ghaskins@novell.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Andi Kleen <andi-suse@firstfloor.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
* x86: fix csum_partial() exportIngo Molnar2008-05-13
| | | | | | | | | | | | | | | | | | | Fix this symbol export problem: Building modules, stage 2. MODPOST 193 modules ERROR: "csum_partial" [fs/reiserfs/reiserfs.ko] undefined! make[1]: *** [__modpost] Error 1 make: *** [modules] Error 2 This is due to a known weakness of symbol exports: if a symbol's only in-core user is an EXPORT_SYMBOL from a lib-y section, the symbol is not linked in. The solution is to move the export to x8664_ksyms_64.c - but the real solution would be to fix kbuild. Signed-off-by: Ingo Molnar <mingo@elte.hu>
generated by cgit v1.2.2 (git 2.25.0) at 2024-11-18 12:29:18 -0500