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2013-05-11perf/x86/intel/lbr: Demand proper privileges for PERF_SAMPLE_BRANCH_KERNELPeter Zijlstra
commit 7cc23cd6c0c7d7f4bee057607e7ce01568925717 upstream. We should always have proper privileges when requesting kernel data. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Andi Kleen <ak@linux.intel.com> Cc: eranian@google.com Link: http://lkml.kernel.org/r/20130503121256.230745028@chello.nl [ Fix build error reported by fengguang.wu@intel.com, propagate error code back. ] Signed-off-by: Ingo Molnar <mingo@kernel.org> Link: http://lkml.kernel.org/n/tip-v0x9ky3ahzr6nm3c6ilwrili@git.kernel.org Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2013-05-11perf/x86/intel/lbr: Fix LBR filterPeter Zijlstra
commit 6e15eb3ba6c0249c9e8c783517d131b47db995ca upstream. The LBR 'from' adddress is under full userspace control; ensure we validate it before reading from it. Note: is_module_text_address() can potentially be quite expensive; for those running into that with high overhead in modules optimize it using an RCU backed rb-tree. Reported-by: Andi Kleen <ak@linux.intel.com> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: eranian@google.com Link: http://lkml.kernel.org/r/20130503121256.158211806@chello.nl Signed-off-by: Ingo Molnar <mingo@kernel.org> Link: http://lkml.kernel.org/n/tip-mk8i82ffzax01cnqo829iy1q@git.kernel.org Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2013-04-25perf/x86: Fix offcore_rsp valid mask for SNB/IVBStephane Eranian
commit f1923820c447e986a9da0fc6bf60c1dccdf0408e upstream. The valid mask for both offcore_response_0 and offcore_response_1 was wrong for SNB/SNB-EP, IVB/IVB-EP. It was possible to write to reserved bit and cause a GP fault crashing the kernel. This patch fixes the problem by correctly marking the reserved bits in the valid mask for all the processors mentioned above. A distinction between desktop and server parts is introduced because bits 24-30 are only available on the server parts. This version of the patch is just a rebase to perf/urgent tree and should apply to older kernels as well. Signed-off-by: Stephane Eranian <eranian@google.com> Cc: peterz@infradead.org Cc: jolsa@redhat.com Cc: ak@linux.intel.com Signed-off-by: Ingo Molnar <mingo@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2013-03-20perf,x86: fix wrmsr_on_cpu() warning on suspend/resumeLinus Torvalds
commit 2a6e06b2aed6995af401dcd4feb5e79a0c7ea554 upstream. Commit 1d9d8639c063 ("perf,x86: fix kernel crash with PEBS/BTS after suspend/resume") fixed a crash when doing PEBS performance profiling after resuming, but in using init_debug_store_on_cpu() to restore the DS_AREA mtrr it also resulted in a new WARN_ON() triggering. init_debug_store_on_cpu() uses "wrmsr_on_cpu()", which in turn uses CPU cross-calls to do the MSR update. Which is not really valid at the early resume stage, and the warning is quite reasonable. Now, it all happens to _work_, for the simple reason that smp_call_function_single() ends up just doing the call directly on the CPU when the CPU number matches, but we really should just do the wrmsr() directly instead. This duplicates the wrmsr() logic, but hopefully we can just remove the wrmsr_on_cpu() version eventually. Reported-and-tested-by: Parag Warudkar <parag.lkml@gmail.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2013-03-20perf,x86: fix kernel crash with PEBS/BTS after suspend/resumeStephane Eranian
commit 1d9d8639c063caf6efc2447f5f26aa637f844ff6 upstream. This patch fixes a kernel crash when using precise sampling (PEBS) after a suspend/resume. Turns out the CPU notifier code is not invoked on CPU0 (BP). Therefore, the DS_AREA (used by PEBS) is not restored properly by the kernel and keeps it power-on/resume value of 0 causing any PEBS measurement to crash when running on CPU0. The workaround is to add a hook in the actual resume code to restore the DS Area MSR value. It is invoked for all CPUS. So for all but CPU0, the DS_AREA will be restored twice but this is harmless. Reported-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Stephane Eranian <eranian@google.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2013-02-28x86: Hyper-V: register clocksource only if its advertisedOlaf Hering
commit 32068f6527b8f1822a30671dedaf59c567325026 upstream. Enable hyperv_clocksource only if its advertised as a feature. XenServer 6 returns the signature which is checked in ms_hyperv_platform(), but it does not offer all features. Currently the clocksource is enabled unconditionally in ms_hyperv_init_platform(), and the result is a hanging guest. Hyper-V spec Bit 1 indicates the availability of Partition Reference Counter. Register the clocksource only if this bit is set. The guest in question prints this in dmesg: [ 0.000000] Hypervisor detected: Microsoft HyperV [ 0.000000] HyperV: features 0x70, hints 0x0 This bug can be reproduced easily be setting 'viridian=1' in a HVM domU .cfg file. A workaround without this patch is to boot the HVM guest with 'clocksource=jiffies'. Signed-off-by: Olaf Hering <olaf@aepfle.de> Link: http://lkml.kernel.org/r/1359940959-32168-1-git-send-email-kys@microsoft.com Signed-off-by: K. Y. Srinivasan <kys@microsoft.com> Signed-off-by: H. Peter Anvin <hpa@linux.intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2013-01-17x86, amd: Disable way access filter on Piledriver CPUsAndre Przywara
commit 2bbf0a1427c377350f001fbc6260995334739ad7 upstream. The Way Access Filter in recent AMD CPUs may hurt the performance of some workloads, caused by aliasing issues in the L1 cache. This patch disables it on the affected CPUs. The issue is similar to that one of last year: http://lkml.indiana.edu/hypermail/linux/kernel/1107.3/00041.html This new patch does not replace the old one, we just need another quirk for newer CPUs. The performance penalty without the patch depends on the circumstances, but is a bit less than the last year's 3%. The workloads affected would be those that access code from the same physical page under different virtual addresses, so different processes using the same libraries with ASLR or multiple instances of PIE-binaries. The code needs to be accessed simultaneously from both cores of the same compute unit. More details can be found here: http://developer.amd.com/Assets/SharedL1InstructionCacheonAMD15hCPU.pdf CPUs affected are anything with the core known as Piledriver. That includes the new parts of the AMD A-Series (aka Trinity) and the just released new CPUs of the FX-Series (aka Vishera). The model numbering is a bit odd here: FX CPUs have model 2, A-Series has model 10h, with possible extensions to 1Fh. Hence the range of model ids. Signed-off-by: Andre Przywara <osp@andrep.de> Link: http://lkml.kernel.org/r/1351700450-9277-1-git-send-email-osp@andrep.de Signed-off-by: H. Peter Anvin <hpa@linux.intel.com> Signed-off-by: CAI Qian <caiqian@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2013-01-11x86, amd: Disable way access filter on Piledriver CPUsAndre Przywara
commit 2bbf0a1427c377350f001fbc6260995334739ad7 upstream. The Way Access Filter in recent AMD CPUs may hurt the performance of some workloads, caused by aliasing issues in the L1 cache. This patch disables it on the affected CPUs. The issue is similar to that one of last year: http://lkml.indiana.edu/hypermail/linux/kernel/1107.3/00041.html This new patch does not replace the old one, we just need another quirk for newer CPUs. The performance penalty without the patch depends on the circumstances, but is a bit less than the last year's 3%. The workloads affected would be those that access code from the same physical page under different virtual addresses, so different processes using the same libraries with ASLR or multiple instances of PIE-binaries. The code needs to be accessed simultaneously from both cores of the same compute unit. More details can be found here: http://developer.amd.com/Assets/SharedL1InstructionCacheonAMD15hCPU.pdf CPUs affected are anything with the core known as Piledriver. That includes the new parts of the AMD A-Series (aka Trinity) and the just released new CPUs of the FX-Series (aka Vishera). The model numbering is a bit odd here: FX CPUs have model 2, A-Series has model 10h, with possible extensions to 1Fh. Hence the range of model ids. Signed-off-by: Andre Przywara <osp@andrep.de> Link: http://lkml.kernel.org/r/1351700450-9277-1-git-send-email-osp@andrep.de Signed-off-by: H. Peter Anvin <hpa@linux.intel.com> Signed-off-by: CAI Qian <caiqian@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2012-08-09x86/mce: Fix siginfo_t->si_addr value for non-recoverable memory faultsTony Luck
commit 6751ed65dc6642af64f7b8a440a75563c8aab7ae upstream. In commit dad1743e5993f1 ("x86/mce: Only restart instruction after machine check recovery if it is safe") we fixed mce_notify_process() to force a signal to the current process if it was not restartable (RIPV bit not set in MCG_STATUS). But doing it here means that the process doesn't get told the virtual address of the fault via siginfo_t->si_addr. This would prevent application level recovery from the fault. Make a new MF_MUST_KILL flag bit for memory_failure() et al. to use so that we will provide the right information with the signal. Signed-off-by: Tony Luck <tony.luck@intel.com> Acked-by: Borislav Petkov <borislav.petkov@amd.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2012-07-16x86, cpufeature: Rename X86_FEATURE_DTS to X86_FEATURE_DTHERMH. Peter Anvin
commit 4ad33411308596f2f918603509729922a1ec4411 upstream. It makes sense to label "Digital Thermal Sensor" as "DTS", but unfortunately the string "dts" was already used for "Debug Store", and /proc/cpuinfo is a user space ABI. Therefore, rename this to "dtherm". This conflict went into mainline via the hwmon tree without any x86 maintainer ack, and without any kind of hint in the subject. a4659053 x86/hwmon: fix initialization of coretemp Reported-by: Jean Delvare <khali@linux-fr.org> Link: http://lkml.kernel.org/r/4FE34BCB.5050305@linux.intel.com Cc: Jan Beulich <JBeulich@suse.com> Signed-off-by: H. Peter Anvin <hpa@linux.intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2012-06-17x86, MCE, AMD: Make APIC LVT thresholding interrupt optionalBorislav Petkov
commit f227d4306cf30e1d5b6f231e8ef9006c34f3d186 upstream. Currently, the APIC LVT interrupt for error thresholding is implicitly enabled. However, there are models in the F15h range which do not enable it. Make the code machinery which sets up the APIC interrupt support an optional setting and add an ->interrupt_capable member to the bank representation mirroring that capability and enable the interrupt offset programming only if it is true. Simplify code and fixup comment style while at it. Signed-off-by: Borislav Petkov <borislav.petkov@amd.com> Cc: Robert Richter <robert.richter@amd.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2012-06-01MCE: Fix vm86 handling for 32bit mce handlerAndi Kleen
commit a129a7c84582629741e5fa6f40026efcd7a65bd4 upstream. When running on 32bit the mce handler could misinterpret vm86 mode as ring 0. This can affect whether it does recovery or not; it was possible to panic when recovery was actually possible. Fix this by always forcing vm86 to look like ring 3. Signed-off-by: Andi Kleen <ak@linux.intel.com> Signed-off-by: Tony Luck <tony.luck@intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2012-06-01x86/mce: Fix check for processor context when machine check was taken.Tony Luck
commit 875e26648cf9b6db9d8dc07b7959d7c61fb3f49c upstream. Linus pointed out that there was no value is checking whether m->ip was zero - because zero is a legimate value. If we have a reliable (or faked in the VM86 case) "m->cs" we can use it to tell whether we were in user mode or kernelwhen the machine check hit. Reported-by: Linus Torvalds <torvalds@linuxfoundation.org> Signed-off-by: Tony Luck <tony.luck@intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2012-06-01perf/x86: Update event scheduling constraints for AMD family 15h modelsRobert Richter
commit 5bcdf5e4fee3c45e1281c25e4941f2163cb28c65 upstream. This update is for newer family 15h cpu models from 0x02 to 0x1f. Signed-off-by: Robert Richter <robert.richter@amd.com> Acked-by: Peter Zijlstra <peterz@infradead.org> Cc: Stephane Eranian <eranian@google.com> Link: http://lkml.kernel.org/r/1337337642-1621-1-git-send-email-robert.richter@amd.com Signed-off-by: Ingo Molnar <mingo@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2012-05-14x86/mce: Only restart instruction after machine check recovery if it is safeTony Luck
Section 15.3.1.2 of the software developer manual has this to say about the RIPV bit in the IA32_MCG_STATUS register: RIPV (restart IP valid) flag, bit 0 — Indicates (when set) that program execution can be restarted reliably at the instruction pointed to by the instruction pointer pushed on the stack when the machine-check exception is generated. When clear, the program cannot be reliably restarted at the pushed instruction pointer. We need to save the state of this bit in do_machine_check() and use it in mce_notify_process() to force a signal; even if memory_failure() says it made a complete recovery ... e.g. replaced a clean LRU page. Acked-by: Borislav Petkov <bp@amd64.org> Signed-off-by: Tony Luck <tony.luck@intel.com>
2012-04-27x86/amd: Re-enable CPU topology extensions in case BIOS has disabled itAndreas Herrmann
BIOS will switch off the corresponding feature flag on family 15h models 10h-1fh non-desktop CPUs. The topology extension CPUID leafs are required to detect which cores belong to the same compute unit. (thread siblings mask is set accordingly and also correct information about L1i and L2 cache sharing depends on this). W/o this patch we wouldn't see which cores belong to the same compute unit and also cache sharing information for L1i and L2 would be incorrect on such systems. Signed-off-by: Andreas Herrmann <andreas.herrmann3@amd.com> Signed-off-by: Ingo Molnar <mingo@kernel.org>
2012-04-25Merge tag 'l3-fix-for-3.5' of ↵Ingo Molnar
git://git.kernel.org/pub/scm/linux/kernel/git/bp/bp into x86/urgent A small L3 cache index disable fix from Srivatsa Bhat which unifies the way the code checks for already disabled indices. ( Pulling it into v3.4 despite the v3.5 tag - the fix is small and we better keep the same code across kernel versions for such user facing interfaces. ) Signed-off-by: Ingo Molnar <mingo@kernel.org>
2012-04-19x86, intel_cacheinfo: Fix error return code in amd_set_l3_disable_slot()Srivatsa S. Bhat
If the L3 disable slot is already in use, return -EEXIST instead of -EINVAL. The caller, store_cache_disable(), checks this return value to print an appropriate warning. Also, we want to signal with -EEXIST that the current index we're disabling has actually been already disabled on the node: $ echo 12 > /sys/devices/system/cpu/cpu3/cache/index3/cache_disable_0 $ echo 12 > /sys/devices/system/cpu/cpu3/cache/index3/cache_disable_0 -bash: echo: write error: File exists $ echo 12 > /sys/devices/system/cpu/cpu3/cache/index3/cache_disable_1 -bash: echo: write error: File exists $ echo 12 > /sys/devices/system/cpu/cpu5/cache/index3/cache_disable_1 -bash: echo: write error: File exists The old code would say -bash: echo: write error: Invalid argument for disable slot 1 when playing the example above with no output in dmesg, which is clearly misleading. Reported-by: Dan Carpenter <dan.carpenter@oracle.com> Signed-off-by: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com> Link: http://lkml.kernel.org/r/20120419070053.GB16645@elgon.mountain [Boris: add testing for the other index too] Signed-off-by: Borislav Petkov <borislav.petkov@amd.com>
2012-04-16x86/platform: Remove incorrect error message in x86_default_fixup_cpu_id()Andreas Herrmann
It's only called from amd.c:srat_detect_node(). The introduced condition for calling the fixup code is true for all AMD multi-node processors, e.g. Magny-Cours and Interlagos. There we have 2 NUMA nodes on one socket. Thus there are cores having different numa-node-id but with equal phys_proc_id. There is no point to print error messages in such a situation. The confusing/misleading error message was introduced with commit 64be4c1c2428e148de6081af235e2418e6a66dda ("x86: Add x86_init platform override to fix up NUMA core numbering"). Remove the default fixup function (especially the error message) and replace it by a NULL pointer check, move the Numascale-specific condition for calling the fixup into the fixup-function itself and slightly adapt the comment. Signed-off-by: Andreas Herrmann <andreas.herrmann3@amd.com> Acked-by: Borislav Petkov <borislav.petkov@amd.com> Cc: <stable@kernel.org> Cc: <sp@numascale.com> Cc: <bp@amd64.org> Cc: <daniel@numascale-asia.com> Link: http://lkml.kernel.org/r/20120402160648.GR27684@alberich.amd.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2012-04-16x86/amd: Remove broken links from comment and kernel messageAndreas Herrmann
Signed-off-by: Andreas Herrmann <andreas.herrmann3@amd.com> Link: http://lkml.kernel.org/r/20120411151238.GA4794@alberich.amd.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2012-04-04Merge branch 'perf-urgent-for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull perf fixes from Ingo Molnar. * 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: perf/x86/p4: Add format attributes tracing, sched, vfs: Fix 'old_pid' usage in trace_sched_process_exec()
2012-04-03perf/x86/p4: Add format attributesPeter Zijlstra
Steven reported his P4 not booting properly, the missing format attributes cause a NULL ptr deref. Cure this by adding the missing format specification. I took the format description out of the comment near p4_config_pack*() and hope that comment is still relatively accurate. Reported-by: Steven Rostedt <rostedt@goodmis.org> Reported-by: Bruno Prémont <bonbons@linux-vserver.org> Tested-by: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Jiri Olsa <jolsa@redhat.com> Cc: Cyrill Gorcunov <gorcunov@openvz.org> Cc: Lin Ming <ming.m.lin@intel.com> Cc: Stephane Eranian <eranian@google.com> Link: http://lkml.kernel.org/r/1332859842.16159.227.camel@twins Signed-off-by: Ingo Molnar <mingo@kernel.org>
2012-03-31Merge branch 'perf-urgent-for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull perf updates and fixes from Ingo Molnar: "It's mostly fixes, but there's also two late items: - preliminary GTK GUI support for perf report - PMU raw event format descriptors in sysfs, to be parsed by tooling The raw event format in sysfs is a new ABI. For example for the 'CPU' PMU we have: aldebaran:~> ll /sys/bus/event_source/devices/cpu/format/* -r--r--r--. 1 root root 4096 Mar 31 10:29 /sys/bus/event_source/devices/cpu/format/any -r--r--r--. 1 root root 4096 Mar 31 10:29 /sys/bus/event_source/devices/cpu/format/cmask -r--r--r--. 1 root root 4096 Mar 31 10:29 /sys/bus/event_source/devices/cpu/format/edge -r--r--r--. 1 root root 4096 Mar 31 10:29 /sys/bus/event_source/devices/cpu/format/event -r--r--r--. 1 root root 4096 Mar 31 10:29 /sys/bus/event_source/devices/cpu/format/inv -r--r--r--. 1 root root 4096 Mar 31 10:29 /sys/bus/event_source/devices/cpu/format/offcore_rsp -r--r--r--. 1 root root 4096 Mar 31 10:29 /sys/bus/event_source/devices/cpu/format/pc -r--r--r--. 1 root root 4096 Mar 31 10:29 /sys/bus/event_source/devices/cpu/format/umask those lists of fields contain a specific format: aldebaran:~> cat /sys/bus/event_source/devices/cpu/format/offcore_rsp config1:0-63 So, those who wish to specify raw events can now use the following event format: -e cpu/cmask=1,event=2,umask=3 Most people will not want to specify any events (let alone raw events), they'll just use whatever default event the tools use. But for more obscure PMU events that have no cross-architecture generic events the above syntax is more usable and a bit more structured than specifying hex numbers." * 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (41 commits) perf tools: Remove auto-generated bison/flex files perf annotate: Fix off by one symbol hist size allocation and hit accounting perf tools: Add missing ref-cycles event back to event parser perf annotate: addr2line wants addresses in same format as objdump perf probe: Finder fails to resolve function name to address tracing: Fix ent_size in trace output perf symbols: Handle NULL dso in dso__name_len perf symbols: Do not include libgen.h perf tools: Fix bug in raw sample parsing perf tools: Fix display of first level of callchains perf tools: Switch module.h into export.h perf: Move mmap page data_head offset assertion out of header perf: Fix mmap_page capabilities and docs perf diff: Fix to work with new hists design perf tools: Fix modifier to be applied on correct events perf tools: Fix various casting issues for 32 bits perf tools: Simplify event_read_id exit path tracing: Fix ftrace stack trace entries tracing: Move the tracing_on/off() declarations into CONFIG_TRACING perf report: Add a simple GTK2-based 'perf report' browser ...
2012-03-29Merge branch 'x86-x32-for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull x32 support for x86-64 from Ingo Molnar: "This tree introduces the X32 binary format and execution mode for x86: 32-bit data space binaries using 64-bit instructions and 64-bit kernel syscalls. This allows applications whose working set fits into a 32 bits address space to make use of 64-bit instructions while using a 32-bit address space with shorter pointers, more compressed data structures, etc." Fix up trivial context conflicts in arch/x86/{Kconfig,vdso/vma.c} * 'x86-x32-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (71 commits) x32: Fix alignment fail in struct compat_siginfo x32: Fix stupid ia32/x32 inversion in the siginfo format x32: Add ptrace for x32 x32: Switch to a 64-bit clock_t x32: Provide separate is_ia32_task() and is_x32_task() predicates x86, mtrr: Use explicit sizing and padding for the 64-bit ioctls x86/x32: Fix the binutils auto-detect x32: Warn and disable rather than error if binutils too old x32: Only clear TIF_X32 flag once x32: Make sure TS_COMPAT is cleared for x32 tasks fs: Remove missed ->fds_bits from cessation use of fd_set structs internally fs: Fix close_on_exec pointer in alloc_fdtable x32: Drop non-__vdso weak symbols from the x32 VDSO x32: Fix coding style violations in the x32 VDSO code x32: Add x32 VDSO support x32: Allow x32 to be configured x32: If configured, add x32 system calls to system call tables x32: Handle process creation x32: Signal-related system calls x86: Add #ifdef CONFIG_COMPAT to <asm/sys_ia32.h> ...
2012-03-29Merge branch 'x86-urgent-for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull x86 updates from Ingo Molnar. This touches some non-x86 files due to the sanitized INLINE_SPIN_UNLOCK config usage. Fixed up trivial conflicts due to just header include changes (removing headers due to cpu_idle() merge clashing with the <asm/system.h> split). * 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: x86/apic/amd: Be more verbose about LVT offset assignments x86, tls: Off by one limit check x86/ioapic: Add io_apic_ops driver layer to allow interception x86/olpc: Add debugfs interface for EC commands x86: Merge the x86_32 and x86_64 cpu_idle() functions x86/kconfig: Remove CONFIG_TR=y from the defconfigs x86: Stop recursive fault in print_context_stack after stack overflow x86/io_apic: Move and reenable irq only when CONFIG_GENERIC_PENDING_IRQ=y x86/apic: Add separate apic_id_valid() functions for selected apic drivers locking/kconfig: Simplify INLINE_SPIN_UNLOCK usage x86/kconfig: Update defconfigs x86: Fix excessive MSR print out when show_msr is not specified
2012-03-28Merge tag 'split-asm_system_h-for-linus-20120328' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-asm_system Pull "Disintegrate and delete asm/system.h" from David Howells: "Here are a bunch of patches to disintegrate asm/system.h into a set of separate bits to relieve the problem of circular inclusion dependencies. I've built all the working defconfigs from all the arches that I can and made sure that they don't break. The reason for these patches is that I recently encountered a circular dependency problem that came about when I produced some patches to optimise get_order() by rewriting it to use ilog2(). This uses bitops - and on the SH arch asm/bitops.h drags in asm-generic/get_order.h by a circuituous route involving asm/system.h. The main difficulty seems to be asm/system.h. It holds a number of low level bits with no/few dependencies that are commonly used (eg. memory barriers) and a number of bits with more dependencies that aren't used in many places (eg. switch_to()). These patches break asm/system.h up into the following core pieces: (1) asm/barrier.h Move memory barriers here. This already done for MIPS and Alpha. (2) asm/switch_to.h Move switch_to() and related stuff here. (3) asm/exec.h Move arch_align_stack() here. Other process execution related bits could perhaps go here from asm/processor.h. (4) asm/cmpxchg.h Move xchg() and cmpxchg() here as they're full word atomic ops and frequently used by atomic_xchg() and atomic_cmpxchg(). (5) asm/bug.h Move die() and related bits. (6) asm/auxvec.h Move AT_VECTOR_SIZE_ARCH here. Other arch headers are created as needed on a per-arch basis." Fixed up some conflicts from other header file cleanups and moving code around that has happened in the meantime, so David's testing is somewhat weakened by that. We'll find out anything that got broken and fix it.. * tag 'split-asm_system_h-for-linus-20120328' of git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-asm_system: (38 commits) Delete all instances of asm/system.h Remove all #inclusions of asm/system.h Add #includes needed to permit the removal of asm/system.h Move all declarations of free_initmem() to linux/mm.h Disintegrate asm/system.h for OpenRISC Split arch_align_stack() out from asm-generic/system.h Split the switch_to() wrapper out of asm-generic/system.h Move the asm-generic/system.h xchg() implementation to asm-generic/cmpxchg.h Create asm-generic/barrier.h Make asm-generic/cmpxchg.h #include asm-generic/cmpxchg-local.h Disintegrate asm/system.h for Xtensa Disintegrate asm/system.h for Unicore32 [based on ver #3, changed by gxt] Disintegrate asm/system.h for Tile Disintegrate asm/system.h for Sparc Disintegrate asm/system.h for SH Disintegrate asm/system.h for Score Disintegrate asm/system.h for S390 Disintegrate asm/system.h for PowerPC Disintegrate asm/system.h for PA-RISC Disintegrate asm/system.h for MN10300 ...
2012-03-28Disintegrate asm/system.h for X86David Howells
Disintegrate asm/system.h for X86. Signed-off-by: David Howells <dhowells@redhat.com> Acked-by: H. Peter Anvin <hpa@zytor.com> cc: x86@kernel.org
2012-03-26Merge branch 'linus' into perf/urgentIngo Molnar
Merge reason: we need to fix a non-trivial merge conflict. Signed-off-by: Ingo Molnar <mingo@elte.hu>
2012-03-24Merge tag 'bug-for-3.4' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/paulg/linux Pull <linux/bug.h> cleanup from Paul Gortmaker: "The changes shown here are to unify linux's BUG support under the one <linux/bug.h> file. Due to historical reasons, we have some BUG code in bug.h and some in kernel.h -- i.e. the support for BUILD_BUG in linux/kernel.h predates the addition of linux/bug.h, but old code in kernel.h wasn't moved to bug.h at that time. As a band-aid, kernel.h was including <asm/bug.h> to pseudo link them. This has caused confusion[1] and general yuck/WTF[2] reactions. Here is an example that violates the principle of least surprise: CC lib/string.o lib/string.c: In function 'strlcat': lib/string.c:225:2: error: implicit declaration of function 'BUILD_BUG_ON' make[2]: *** [lib/string.o] Error 1 $ $ grep linux/bug.h lib/string.c #include <linux/bug.h> $ We've included <linux/bug.h> for the BUG infrastructure and yet we still get a compile fail! [We've not kernel.h for BUILD_BUG_ON.] Ugh - very confusing for someone who is new to kernel development. With the above in mind, the goals of this changeset are: 1) find and fix any include/*.h files that were relying on the implicit presence of BUG code. 2) find and fix any C files that were consuming kernel.h and hence relying on implicitly getting some/all BUG code. 3) Move the BUG related code living in kernel.h to <linux/bug.h> 4) remove the asm/bug.h from kernel.h to finally break the chain. During development, the order was more like 3-4, build-test, 1-2. But to ensure that git history for bisect doesn't get needless build failures introduced, the commits have been reorderd to fix the problem areas in advance. [1] https://lkml.org/lkml/2012/1/3/90 [2] https://lkml.org/lkml/2012/1/17/414" Fix up conflicts (new radeon file, reiserfs header cleanups) as per Paul and linux-next. * tag 'bug-for-3.4' of git://git.kernel.org/pub/scm/linux/kernel/git/paulg/linux: kernel.h: doesn't explicitly use bug.h, so don't include it. bug: consolidate BUILD_BUG_ON with other bug code BUG: headers with BUG/BUG_ON etc. need linux/bug.h bug.h: add include of it to various implicit C users lib: fix implicit users of kernel.h for TAINT_WARN spinlock: macroize assert_spin_locked to avoid bug.h dependency x86: relocate get/set debugreg fcns to include/asm/debugreg.
2012-03-23bitops: rename for_each_set_bit_cont() in favor of analogous list.h functionAkinobu Mita
This renames for_each_set_bit_cont() to for_each_set_bit_from() because it is analogous to list_for_each_entry_from() in list.h rather than list_for_each_entry_continue(). This doesn't remove for_each_set_bit_cont() for now. Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com> Cc: Robert Richter <robert.richter@amd.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Ingo Molnar <mingo@redhat.com> Cc: "H. Peter Anvin" <hpa@zytor.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-03-23x86: Fix excessive MSR print out when show_msr is not specifiedYinghai Lu
Dave found: | During bootup, I now have 162 messages like this.. | [ 0.227346] MSR0000001b: 00000000fee00900 | [ 0.227465] MSR00000021: 0000000000000001 | [ 0.227584] MSR0000002a: 00000000c1c81400 | | commit 21c3fcf3e39353d4f21d50e257cc74f3204b1988 looks suspect. | It claims that it will only print these out if show_msr= is | passed, but that doesn't seem to be the case. Fix it by changing to the version that checks the index. Reported-and-tested-by: Dave Jones <davej@redhat.com> Signed-off-by: Yinghai Lu <yinghai@kernel.org> Link: http://lkml.kernel.org/r/1332477103-4595-1-git-send-email-yinghai@kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
2012-03-23perf: Fix mmap_page capabilities and docsPeter Zijlstra
Complete the syscall-less self-profiling feature and address all complaints, namely: - capabilities, so we can detect what is actually available at runtime Add a capabilities field to perf_event_mmap_page to indicate what is actually available for use. - on x86: RDPMC weirdness due to being 40/48 bits and not sign-extending properly. - ABI documentation as to how all this stuff works. Also improve the documentation for the new features. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Stephane Eranian <eranian@google.com> Cc: Vince Weaver <vweaver1@eecs.utk.edu> Cc: Arnaldo Carvalho de Melo <acme@infradead.org> Cc: Jiri Olsa <jolsa@redhat.com> Link: http://lkml.kernel.org/r/1332433596.2487.33.camel@twins Signed-off-by: Ingo Molnar <mingo@kernel.org>
2012-03-22Merge branch 'x86-urgent-for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull x86 "urgent" leftovers from Ingo Molnar: "Pending x86/urgent bits that were not high prio enough to warrant -rc-less v3.3-final inclusion." * 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: x86, efi: Fix pointer math issue in handle_ramdisks() x86/ioapic: Add register level checks to detect bogus io-apic entries x86, mce: Fix rcu splat in drain_mce_log_buffer() x86, memblock: Move mem_hole_size() to .init
2012-03-22Merge branch 'x86-mce-for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull MCE changes from Ingo Molnar. * 'x86-mce-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: x86/mce: Fix return value of mce_chrdev_read() when erst is disabled x86/mce: Convert static array of pointers to per-cpu variables x86/mce: Replace hard coded hex constants with symbolic defines x86/mce: Recognise machine check bank signature for data path error x86/mce: Handle "action required" errors x86/mce: Add mechanism to safely save information in MCE handler x86/mce: Create helper function to save addr/misc when needed HWPOISON: Add code to handle "action required" errors. HWPOISON: Clean up memory_failure() vs. __memory_failure()
2012-03-22Merge branch 'x86-fpu-for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull x86/fpu changes from Ingo Molnar. * 'x86-fpu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: i387: Split up <asm/i387.h> into exported and internal interfaces i387: Uninline the generic FP helpers that we expose to kernel modules
2012-03-22Merge branch 'x86-debug-for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull x86/debug changes from Ingo Molnar. * 'x86-debug-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: x86: Fix section warnings x86-64: Fix CFI data for common_interrupt() x86: Properly _init-annotate NMI selftest code x86/debug: Fix/improve the show_msr=<cpus> debug print out
2012-03-20Merge tag 'driver-core-3.3' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core Pull driver core patches for 3.4-rc1 from Greg KH: "Here's the big driver core merge for 3.4-rc1. Lots of various things here, sysfs fixes/tweaks (with the nlink breakage reverted), dynamic debugging updates, w1 drivers, hyperv driver updates, and a variety of other bits and pieces, full information in the shortlog." * tag 'driver-core-3.3' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core: (78 commits) Tools: hv: Support enumeration from all the pools Tools: hv: Fully support the new KVP verbs in the user level daemon Drivers: hv: Support the newly introduced KVP messages in the driver Drivers: hv: Add new message types to enhance KVP regulator: Support driver probe deferral Revert "sysfs: Kill nlink counting." uevent: send events in correct order according to seqnum (v3) driver core: minor comment formatting cleanups driver core: move the deferred probe pointer into the private area drivercore: Add driver probe deferral mechanism DS2781 Maxim Stand-Alone Fuel Gauge battery and w1 slave drivers w1_bq27000: Only one thread can access the bq27000 at a time. w1_bq27000 - remove w1_bq27000_write w1_bq27000: remove unnecessary NULL test. sysfs: Fix memory leak in sysfs_sd_setsecdata(). intel_idle: Revert change of auto_demotion_disable_flags for Nehalem w1: Fix w1_bq27000 driver-core: documentation: fix up Greg's email address powernow-k6: Really enable auto-loading powernow-k7: Fix CPU family number ...
2012-03-16perf: Adding sysfs group format attribute for pmu deviceJiri Olsa
Adding sysfs group 'format' attribute for pmu device that contains a syntax description on how to construct raw events. The event configuration is described in following struct pefr_event_attr attributes: config config1 config2 Each sysfs attribute within the format attribute group, describes mapping of name and bitfield definition within one of above attributes. eg: "/sys/...<dev>/format/event" contains "config:0-7" "/sys/...<dev>/format/umask" contains "config:8-15" "/sys/...<dev>/format/usr" contains "config:16" the attribute value syntax is: line: config ':' bits config: 'config' | 'config1' | 'config2" bits: bits ',' bit_term | bit_term bit_term: VALUE '-' VALUE | VALUE Adding format attribute definitions for x86 cpu pmus. Acked-by: Peter Zijlstra <peterz@infradead.org> Signed-off-by: Peter Zijlstra <peterz@infradead.org> Signed-off-by: Jiri Olsa <jolsa@redhat.com> Link: http://lkml.kernel.org/n/tip-vhdk5y2hyype9j63prymty36@git.kernel.org Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2012-03-14Merge tag 'mce-for-tip' of ↵Ingo Molnar
git://git.kernel.org/pub/scm/linux/kernel/git/ras/ras into x86/mce Apply two miscellaneous MCE fixes. Signed-off-by: Ingo Molnar <mingo@elte.hu>
2012-03-14Merge tag 'v3.3-rc7' into x86/mceIngo Molnar
Merge reason: Update from an ancient -rc1 base to an almost-final stable kernel. Signed-off-by: Ingo Molnar <mingo@elte.hu>
2012-03-12Merge branch 'perf/hw-branch-sampling' into perf/coreIngo Molnar
Merge reason: The 'perf record -b' hardware branch sampling feature is ready for upstream. Signed-off-by: Ingo Molnar <mingo@elte.hu>
2012-03-12perf/x86: Prettify pmu config literalsPeter Zijlstra
I got somewhat tired of having to decode hex numbers.. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Acked-by: Thomas Gleixner <tglx@linutronix.de> Cc: Stephane Eranian <eranian@google.com> Cc: Robert Richter <robert.richter@amd.com> Link: http://lkml.kernel.org/n/tip-0vsy1sgywc4uar3mu1szm0rg@git.kernel.org Signed-off-by: Ingo Molnar <mingo@elte.hu>
2012-03-12Merge branch 'perf/urgent' into perf/coreIngo Molnar
Merge reason: We are going to queue up a dependent patch. Signed-off-by: Ingo Molnar <mingo@elte.hu>
2012-03-12perf/x86: Fix local vs remote memory events for NHM/WSMPeter Zijlstra
Verified using the below proglet.. before: [root@westmere ~]# perf stat -e node-stores -e node-store-misses ./numa 0 remote write Performance counter stats for './numa 0': 2,101,554 node-stores 2,096,931 node-store-misses 5.021546079 seconds time elapsed [root@westmere ~]# perf stat -e node-stores -e node-store-misses ./numa 1 local write Performance counter stats for './numa 1': 501,137 node-stores 199 node-store-misses 5.124451068 seconds time elapsed After: [root@westmere ~]# perf stat -e node-stores -e node-store-misses ./numa 0 remote write Performance counter stats for './numa 0': 2,107,516 node-stores 2,097,187 node-store-misses 5.012755149 seconds time elapsed [root@westmere ~]# perf stat -e node-stores -e node-store-misses ./numa 1 local write Performance counter stats for './numa 1': 2,063,355 node-stores 165 node-store-misses 5.082091494 seconds time elapsed #define _GNU_SOURCE #include <sched.h> #include <stdio.h> #include <errno.h> #include <sys/mman.h> #include <sys/types.h> #include <dirent.h> #include <signal.h> #include <unistd.h> #include <numaif.h> #include <stdlib.h> #define SIZE (32*1024*1024) volatile int done; void sig_done(int sig) { done = 1; } int main(int argc, char **argv) { cpu_set_t *mask, *mask2; size_t size; int i, err, t; int nrcpus = 1024; char *mem; unsigned long nodemask = 0x01; /* node 0 */ DIR *node; struct dirent *de; int read = 0; int local = 0; if (argc < 2) { printf("usage: %s [0-3]\n", argv[0]); printf(" bit0 - local/remote\n"); printf(" bit1 - read/write\n"); exit(0); } switch (atoi(argv[1])) { case 0: printf("remote write\n"); break; case 1: printf("local write\n"); local = 1; break; case 2: printf("remote read\n"); read = 1; break; case 3: printf("local read\n"); local = 1; read = 1; break; } mask = CPU_ALLOC(nrcpus); size = CPU_ALLOC_SIZE(nrcpus); CPU_ZERO_S(size, mask); node = opendir("/sys/devices/system/node/node0/"); if (!node) perror("opendir"); while ((de = readdir(node))) { int cpu; if (sscanf(de->d_name, "cpu%d", &cpu) == 1) CPU_SET_S(cpu, size, mask); } closedir(node); mask2 = CPU_ALLOC(nrcpus); CPU_ZERO_S(size, mask2); for (i = 0; i < size; i++) CPU_SET_S(i, size, mask2); CPU_XOR_S(size, mask2, mask2, mask); // invert if (!local) mask = mask2; err = sched_setaffinity(0, size, mask); if (err) perror("sched_setaffinity"); mem = mmap(0, SIZE, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0); err = mbind(mem, SIZE, MPOL_BIND, &nodemask, 8*sizeof(nodemask), MPOL_MF_MOVE); if (err) perror("mbind"); signal(SIGALRM, sig_done); alarm(5); if (!read) { while (!done) { for (i = 0; i < SIZE; i++) mem[i] = 0x01; } } else { while (!done) { for (i = 0; i < SIZE; i++) t += *(volatile char *)(mem + i); } } return 0; } Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Stephane Eranian <eranian@google.com> Cc: <stable@kernel.org> Link: http://lkml.kernel.org/n/tip-tq73sxus35xmqpojf7ootxgs@git.kernel.org Signed-off-by: Ingo Molnar <mingo@elte.hu>
2012-03-09Merge 3.3-rc6 into driver-core-nextGreg Kroah-Hartman
This was done to resolve a conflict in the drivers/base/cpu.c file. Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2012-03-07x86, mce: Fix rcu splat in drain_mce_log_buffer()Srivatsa S. Bhat
While booting, the following message is seen: [ 21.665087] =============================== [ 21.669439] [ INFO: suspicious RCU usage. ] [ 21.673798] 3.2.0-0.0.0.28.36b5ec9-default #2 Not tainted [ 21.681353] ------------------------------- [ 21.685864] arch/x86/kernel/cpu/mcheck/mce.c:194 suspicious rcu_dereference_index_check() usage! [ 21.695013] [ 21.695014] other info that might help us debug this: [ 21.695016] [ 21.703488] [ 21.703489] rcu_scheduler_active = 1, debug_locks = 1 [ 21.710426] 3 locks held by modprobe/2139: [ 21.714754] #0: (&__lockdep_no_validate__){......}, at: [<ffffffff8133afd3>] __driver_attach+0x53/0xa0 [ 21.725020] #1: [ 21.725323] ioatdma: Intel(R) QuickData Technology Driver 4.00 [ 21.733206] (&__lockdep_no_validate__){......}, at: [<ffffffff8133afe1>] __driver_attach+0x61/0xa0 [ 21.743015] #2: (i7core_edac_lock){+.+.+.}, at: [<ffffffffa01cfa5f>] i7core_probe+0x1f/0x5c0 [i7core_edac] [ 21.753708] [ 21.753709] stack backtrace: [ 21.758429] Pid: 2139, comm: modprobe Not tainted 3.2.0-0.0.0.28.36b5ec9-default #2 [ 21.768253] Call Trace: [ 21.770838] [<ffffffff810977cd>] lockdep_rcu_suspicious+0xcd/0x100 [ 21.777366] [<ffffffff8101aa41>] drain_mcelog_buffer+0x191/0x1b0 [ 21.783715] [<ffffffff8101aa78>] mce_register_decode_chain+0x18/0x20 [ 21.790430] [<ffffffffa01cf8db>] i7core_register_mci+0x2fb/0x3e4 [i7core_edac] [ 21.798003] [<ffffffffa01cfb14>] i7core_probe+0xd4/0x5c0 [i7core_edac] [ 21.804809] [<ffffffff8129566b>] local_pci_probe+0x5b/0xe0 [ 21.810631] [<ffffffff812957c9>] __pci_device_probe+0xd9/0xe0 [ 21.816650] [<ffffffff813362e4>] ? get_device+0x14/0x20 [ 21.822178] [<ffffffff81296916>] pci_device_probe+0x36/0x60 [ 21.828061] [<ffffffff8133ac8a>] really_probe+0x7a/0x2b0 [ 21.833676] [<ffffffff8133af23>] driver_probe_device+0x63/0xc0 [ 21.839868] [<ffffffff8133b01b>] __driver_attach+0x9b/0xa0 [ 21.845718] [<ffffffff8133af80>] ? driver_probe_device+0xc0/0xc0 [ 21.852027] [<ffffffff81339168>] bus_for_each_dev+0x68/0x90 [ 21.857876] [<ffffffff8133aa3c>] driver_attach+0x1c/0x20 [ 21.863462] [<ffffffff8133a64d>] bus_add_driver+0x16d/0x2b0 [ 21.869377] [<ffffffff8133b6dc>] driver_register+0x7c/0x160 [ 21.875220] [<ffffffff81296bda>] __pci_register_driver+0x6a/0xf0 [ 21.881494] [<ffffffffa01fe000>] ? 0xffffffffa01fdfff [ 21.886846] [<ffffffffa01fe047>] i7core_init+0x47/0x1000 [i7core_edac] [ 21.893737] [<ffffffff810001ce>] do_one_initcall+0x3e/0x180 [ 21.899670] [<ffffffff810a9b95>] sys_init_module+0xc5/0x220 [ 21.905542] [<ffffffff8149bc39>] system_call_fastpath+0x16/0x1b Fix this by using ACCESS_ONCE() instead of rcu_dereference_check_mce() over mcelog.next. Since the access to each entry is controlled by the ->finished field, ACCESS_ONCE() should work just fine. An rcu_dereference is unnecessary here. Signed-off-by: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com> Suggested-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Tony Luck <tony.luck@intel.com> Signed-off-by: Borislav Petkov <borislav.petkov@amd.com>
2012-03-05perf: Add callback to flush branch_stack on context switchStephane Eranian
With branch stack sampling, it is possible to filter by priv levels. In system-wide mode, that means it is possible to capture only user level branches. The builtin SW LBR filter needs to disassemble code based on LBR captured addresses. For that, it needs to know the task the addresses are associated with. Because of context switches, the content of the branch stack buffer may contain addresses from different tasks. We need a callback on context switch to either flush the branch stack or save it. This patch adds a new callback in struct pmu which is called during context switches. The callback is called only when necessary. That is when a system-wide context has, at least, one event which uses PERF_SAMPLE_BRANCH_STACK. The callback is never called for per-thread context. In this version, the Intel x86 code simply flushes (resets) the LBR on context switches (fills it with zeroes). Those zeroed branches are then filtered out by the SW filter. Signed-off-by: Stephane Eranian <eranian@google.com> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Link: http://lkml.kernel.org/r/1328826068-11713-11-git-send-email-eranian@google.com Signed-off-by: Ingo Molnar <mingo@elte.hu>
2012-03-05