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2012-02-29i387: re-introduce FPU state preloading at context switch timeLinus Torvalds
commit 34ddc81a230b15c0e345b6b253049db731499f7e upstream. After all the FPU state cleanups and finally finding the problem that caused all our FPU save/restore problems, this re-introduces the preloading of FPU state that was removed in commit b3b0870ef3ff ("i387: do not preload FPU state at task switch time"). However, instead of simply reverting the removal, this reimplements preloading with several fixes, most notably - properly abstracted as a true FPU state switch, rather than as open-coded save and restore with various hacks. In particular, implementing it as a proper FPU state switch allows us to optimize the CR0.TS flag accesses: there is no reason to set the TS bit only to then almost immediately clear it again. CR0 accesses are quite slow and expensive, don't flip the bit back and forth for no good reason. - Make sure that the same model works for both x86-32 and x86-64, so that there are no gratuitous differences between the two due to the way they save and restore segment state differently due to architectural differences that really don't matter to the FPU state. - Avoid exposing the "preload" state to the context switch routines, and in particular allow the concept of lazy state restore: if nothing else has used the FPU in the meantime, and the process is still on the same CPU, we can avoid restoring state from memory entirely, just re-expose the state that is still in the FPU unit. That optimized lazy restore isn't actually implemented here, but the infrastructure is set up for it. Of course, older CPU's that use 'fnsave' to save the state cannot take advantage of this, since the state saving also trashes the state. In other words, there is now an actual _design_ to the FPU state saving, rather than just random historical baggage. Hopefully it's easier to follow as a result. Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2012-02-29i387: do not preload FPU state at task switch timeLinus Torvalds
commit b3b0870ef3ffed72b92415423da864f440f57ad6 upstream. Yes, taking the trap to re-load the FPU/MMX state is expensive, but so is spending several days looking for a bug in the state save/restore code. And the preload code has some rather subtle interactions with both paravirtualization support and segment state restore, so it's not nearly as simple as it should be. Also, now that we no longer necessarily depend on a single bit (ie TS_USEDFPU) for keeping track of the state of the FPU, we migth be able to do better. If we are really switching between two processes that keep touching the FP state, save/restore is inevitable, but in the case of having one process that does most of the FPU usage, we may actually be able to do much better than the preloading. In particular, we may be able to keep track of which CPU the process ran on last, and also per CPU keep track of which process' FP state that CPU has. For modern CPU's that don't destroy the FPU contents on save time, that would allow us to do a lazy restore by just re-enabling the existing FPU state - with no restore cost at all! Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2011-06-09exec: delay address limit change until point of no returnMathias Krause
Unconditionally changing the address limit to USER_DS and not restoring it to its old value in the error path is wrong because it prevents us using kernel memory on repeated calls to this function. This, in fact, breaks the fallback of hard coded paths to the init program from being ever successful if the first candidate fails to load. With this patch applied switching to USER_DS is delayed until the point of no return is reached which makes it possible to have a multi-arch rootfs with one arch specific init binary for each of the (hard coded) probed paths. Since the address limit is already set to USER_DS when start_thread() will be invoked, this redundancy can be safely removed. Signed-off-by: Mathias Krause <minipli@googlemail.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: stable@kernel.org Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-01-12cpuidle/x86/perf: fix power:cpu_idle double end events and throw cpu_idle ↵Thomas Renninger
events from the cpuidle layer Currently intel_idle and acpi_idle driver show double cpu_idle "exit idle" events -> this patch fixes it and makes cpu_idle events throwing less complex. It also introduces cpu_idle events for all architectures which use the cpuidle subsystem, namely: - arch/arm/mach-at91/cpuidle.c - arch/arm/mach-davinci/cpuidle.c - arch/arm/mach-kirkwood/cpuidle.c - arch/arm/mach-omap2/cpuidle34xx.c - arch/drivers/acpi/processor_idle.c (for all cases, not only mwait) - arch/x86/kernel/process.c (did throw events before, but was a mess) - drivers/idle/intel_idle.c (did throw events before) Convention should be: Fire cpu_idle events inside the current pm_idle function (not somewhere down the the callee tree) to keep things easy. Current possible pm_idle functions in X86: c1e_idle, poll_idle, cpuidle_idle_call, mwait_idle, default_idle -> this is really easy is now. This affects userspace: The type field of the cpu_idle power event can now direclty get mapped to: /sys/devices/system/cpu/cpuX/cpuidle/stateX/{name,desc,usage,time,...} instead of throwing very CPU/mwait specific values. This change is not visible for the intel_idle driver. For the acpi_idle driver it should only be visible if the vendor misses out C-states in his BIOS. Another (perf timechart) patch reads out cpuidle info of cpu_idle events from: /sys/.../cpuidle/stateX/*, then the cpuidle events are mapped to the correct C-/cpuidle state again, even if e.g. vendors miss out C-states in their BIOS and for example only export C1 and C3. -> everything is fine. Signed-off-by: Thomas Renninger <trenn@suse.de> CC: Robert Schoene <robert.schoene@tu-dresden.de> CC: Jean Pihet <j-pihet@ti.com> CC: Arjan van de Ven <arjan@linux.intel.com> CC: Ingo Molnar <mingo@elte.hu> CC: Frederic Weisbecker <fweisbec@gmail.com> CC: linux-pm@lists.linux-foundation.org CC: linux-acpi@vger.kernel.org CC: linux-kernel@vger.kernel.org CC: linux-perf-users@vger.kernel.org CC: linux-omap@vger.kernel.org Signed-off-by: Len Brown <len.brown@intel.com>
2011-01-04perf: Clean up power events by introducing new, more generic onesThomas Renninger
Add these new power trace events: power:cpu_idle power:cpu_frequency power:machine_suspend The old C-state/idle accounting events: power:power_start power:power_end Have now a replacement (but we are still keeping the old tracepoints for compatibility): power:cpu_idle and power:power_frequency is replaced with: power:cpu_frequency power:machine_suspend is newly introduced. Jean Pihet has a patch integrated into the generic layer (kernel/power/suspend.c) which will make use of it. the type= field got removed from both, it was never used and the type is differed by the event type itself. perf timechart userspace tool gets adjusted in a separate patch. Signed-off-by: Thomas Renninger <trenn@suse.de> Signed-off-by: Ingo Molnar <mingo@elte.hu> Acked-by: Arjan van de Ven <arjan@linux.intel.com> Acked-by: Jean Pihet <jean.pihet@newoldbits.com> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: rjw@sisk.pl LKML-Reference: <1294073445-14812-3-git-send-email-trenn@suse.de> Signed-off-by: Ingo Molnar <mingo@elte.hu> LKML-Reference: <1290072314-31155-2-git-send-email-trenn@suse.de>
2010-06-18x86, perf: Add power_end event to process_*.c cpu_idle routineRobert Schöne
Systems using the idle thread from process_32.c and process_64.c do not generate power_end events which could be traced using perf. This patch adds the event generation for such systems. Signed-off-by: Robert Schoene <robert.schoene@tu-dresden.de> Acked-by: Arjan van de Ven <arjan@linux.intel.com> Cc: Peter Zijlstra <peterz@infradead.org> LKML-Reference: <1276515440.5441.45.camel@localhost> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2010-05-18Merge branch 'x86-fpu-for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip * 'x86-fpu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: x86, fpu: Use static_cpu_has() to implement use_xsave() x86: Add new static_cpu_has() function using alternatives x86, fpu: Use the proper asm constraint in use_xsave() x86, fpu: Unbreak FPU emulation x86: Introduce 'struct fpu' and related API x86: Eliminate TS_XSAVE x86-32: Don't set ignore_fpu_irq in simd exception x86: Merge kernel_math_error() into math_error() x86: Merge simd_math_error() into math_error() x86-32: Rework cache flush denied handler Fix trivial conflict in arch/x86/kernel/process.c
2010-05-10x86: Introduce 'struct fpu' and related APIAvi Kivity
Currently all fpu state access is through tsk->thread.xstate. Since we wish to generalize fpu access to non-task contexts, wrap the state in a new 'struct fpu' and convert existing access to use an fpu API. Signal frame handlers are not converted to the API since they will remain task context only things. Signed-off-by: Avi Kivity <avi@redhat.com> Acked-by: Suresh Siddha <suresh.b.siddha@intel.com> LKML-Reference: <1273135546-29690-3-git-send-email-avi@redhat.com> Signed-off-by: H. Peter Anvin <hpa@zytor.com>
2010-03-26x86, perf, bts, mm: Delete the never used BTS-ptrace codePeter Zijlstra
Support for the PMU's BTS features has been upstreamed in v2.6.32, but we still have the old and disabled ptrace-BTS, as Linus noticed it not so long ago. It's buggy: TIF_DEBUGCTLMSR is trampling all over that MSR without regard for other uses (perf) and doesn't provide the flexibility needed for perf either. Its users are ptrace-block-step and ptrace-bts, since ptrace-bts was never used and ptrace-block-step can be implemented using a much simpler approach. So axe all 3000 lines of it. That includes the *locked_memory*() APIs in mm/mlock.c as well. Reported-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Roland McGrath <roland@redhat.com> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Markus Metzger <markus.t.metzger@intel.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Andrew Morton <akpm@linux-foundation.org> LKML-Reference: <20100325135413.938004390@chello.nl> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2010-02-28Merge branch 'x86-asm-for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip * 'x86-asm-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: x86: Mark atomic irq ops raw for 32bit legacy x86: Merge show_regs() x86: Macroise x86 cache descriptors x86-32: clean up rwsem inline asm statements x86: Merge asm/atomic_{32,64}.h x86: Sync asm/atomic_32.h and asm/atomic_64.h x86: Split atomic64_t functions into seperate headers x86-64: Modify memcpy()/memset() alternatives mechanism x86-64: Modify copy_user_generic() alternatives mechanism x86: Lift restriction on the location of FIX_BTMAP_* x86, core: Optimize hweight32()
2010-01-13x86: Merge show_regs()Brian Gerst
Using kernel_stack_pointer() allows 32-bit and 64-bit versions to be merged. This is more correct for 64-bit, since the old %rsp is always saved on the stack. Signed-off-by: Brian Gerst <brgerst@gmail.com> LKML-Reference: <1263397555-27695-1-git-send-email-brgerst@gmail.com> Signed-off-by: H. Peter Anvin <hpa@zytor.com>
2009-12-28x86: Use KERN_DEFAULT log-level in __show_regs()Pekka Enberg
Andrew Morton reported a strange looking kmemcheck warning: WARNING: kmemcheck: Caught 32-bit read from uninitialized memory (ffff88004fba6c20) 0000000000000000310000000000000000000000000000002413000000c9ffff u u u u u u u u u u u u u u u u i i i i i i i i u u u u u u u u [<ffffffff810af3aa>] kmemleak_scan+0x25a/0x540 [<ffffffff810afbcb>] kmemleak_scan_thread+0x5b/0xe0 [<ffffffff8104d0fe>] kthread+0x9e/0xb0 [<ffffffff81003074>] kernel_thread_helper+0x4/0x10 [<ffffffffffffffff>] 0xffffffffffffffff The above printout is missing register dump completely. The problem here is that the output comes from syslog which doesn't show KERN_INFO log-level messages. We didn't see this before because both of us were testing on 32-bit kernels which use the _default_ log-level. Fix that up by explicitly using KERN_DEFAULT log-level for __show_regs() printks. Signed-off-by: Pekka Enberg <penberg@cs.helsinki.fi> Cc: Vegard Nossum <vegard.nossum@gmail.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Arjan van de Ven <arjan@infradead.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> LKML-Reference: <1261988819.4641.2.camel@penberg-laptop> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-12-15Merge branch 'x86/asm' into x86/urgentIngo Molnar
Merge reason: it's stable so lets push it upstream. Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-12-10x86: Merge kernel_thread()Brian Gerst
Signed-off-by: Brian Gerst <brgerst@gmail.com> LKML-Reference: <1260380084-3707-6-git-send-email-brgerst@gmail.com> Signed-off-by: H. Peter Anvin <hpa@zytor.com>
2009-12-10x86: Sync 32/64-bit kernel_threadBrian Gerst
Signed-off-by: Brian Gerst <brgerst@gmail.com> LKML-Reference: <1260380084-3707-5-git-send-email-brgerst@gmail.com> Signed-off-by: H. Peter Anvin <hpa@zytor.com>
2009-12-10x86, 32-bit: Use same regs as 64-bit for kernel_thread_helperBrian Gerst
The arg should be in %eax, but that is clobbered by the return value of clone. The function pointer can be in any register. Also, don't push args onto the stack, since regparm(3) is the normal calling convention now. Signed-off-by: Brian Gerst <brgerst@gmail.com> LKML-Reference: <1260380084-3707-4-git-send-email-brgerst@gmail.com> Signed-off-by: H. Peter Anvin <hpa@zytor.com>
2009-12-09x86: Merge sys_cloneBrian Gerst
Change 32-bit sys_clone to new PTREGSCALL stub, and merge with 64-bit. Signed-off-by: Brian Gerst <brgerst@gmail.com> LKML-Reference: <1260403316-5679-7-git-send-email-brgerst@gmail.com> Signed-off-by: H. Peter Anvin <hpa@zytor.com>
2009-12-09x86: Merge sys_execveBrian Gerst
Change 32-bit sys_execve to PTREGSCALL3, and merge with 64-bit. Signed-off-by: Brian Gerst <brgerst@gmail.com> LKML-Reference: <1260403316-5679-4-git-send-email-brgerst@gmail.com> Signed-off-by: H. Peter Anvin <hpa@zytor.com>
2009-12-09x86: Factor duplicated code out of __show_regs() into show_regs_common()Andy Isaacson
Unify x86_32 and x86_64 implementations of __show_regs() header, standardizing on the x86_64 format string in the process. Also, 32-bit will now call print_modules. Signed-off-by: Andy Isaacson <adi@hexapodia.org> Cc: Arjan van de Ven <arjan@linux.intel.com> Cc: Robert Hancock <hancockrwd@gmail.com> Cc: Richard Zidlicky <rz@linux-m68k.org> Cc: Andrew Morton <akpm@linux-foundation.org> LKML-Reference: <20091208082942.GA27174@hexapodia.org> [ v2: resolved conflict ] Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-12-05Merge branch 'x86-debug-for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip * 'x86-debug-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: x86: Limit number of per cpu TSC sync messages x86: dumpstack, 64-bit: Disable preemption when walking the IRQ/exception stacks x86: dumpstack: Clean up the x86_stack_ids[][] initalization and other details x86, cpu: mv display_cacheinfo -> cpu_detect_cache_sizes x86: Suppress stack overrun message for init_task x86: Fix cpu_devs[] initialization in early_cpu_init() x86: Remove CPU cache size output for non-Intel too x86: Minimise printk spew from per-vendor init code x86: Remove the CPU cache size printk's cpumask: Avoid cpumask_t in arch/x86/kernel/apic/nmi.c x86: Make sure we also print a Code: line for show_regs()
2009-12-05Merge branch 'x86-cleanups-for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip * 'x86-cleanups-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: x86: Fix a section mismatch in arch/x86/kernel/setup.c x86: Fixup last users of irq_chip->typename x86: Remove BKL from apm_32 x86: Remove BKL from microcode x86: use kernel_stack_pointer() in kprobes.c x86: use kernel_stack_pointer() in kgdb.c x86: use kernel_stack_pointer() in dumpstack.c x86: use kernel_stack_pointer() in process_32.c
2009-11-08hw-breakpoints: Rewrite the hw-breakpoints layer on top of perf eventsFrederic Weisbecker
This patch rebase the implementation of the breakpoints API on top of perf events instances. Each breakpoints are now perf events that handle the register scheduling, thread/cpu attachment, etc.. The new layering is now made as follows: ptrace kgdb ftrace perf syscall \ | / / \ | / / / Core breakpoint API / / | / | / Breakpoints perf events | | Breakpoints PMU ---- Debug Register constraints handling (Part of core breakpoint API) | | Hardware debug registers Reasons of this rewrite: - Use the centralized/optimized pmu registers scheduling, implying an easier arch integration - More powerful register handling: perf attributes (pinned/flexible events, exclusive/non-exclusive, tunable period, etc...) Impact: - New perf ABI: the hardware breakpoints counters - Ptrace breakpoints setting remains tricky and still needs some per thread breakpoints references. Todo (in the order): - Support breakpoints perf counter events for perf tools (ie: implement perf_bpcounter_event()) - Support from perf tools Changes in v2: - Follow the perf "event " rename - The ptrace regression have been fixed (ptrace breakpoint perf events weren't released when a task ended) - Drop the struct hw_breakpoint and store generic fields in perf_event_attr. - Separate core and arch specific headers, drop asm-generic/hw_breakpoint.h and create linux/hw_breakpoint.h - Use new generic len/type for breakpoint - Handle off case: when breakpoints api is not supported by an arch Changes in v3: - Fix broken CONFIG_KVM, we need to propagate the breakpoint api changes to kvm when we exit the guest and restore the bp registers to the host. Changes in v4: - Drop the hw_breakpoint_restore() stub as it is only used by KVM - EXPORT_SYMBOL_GPL hw_breakpoint_restore() as KVM can be built as a module - Restore the breakpoints unconditionally on kvm guest exit: TIF_DEBUG_THREAD doesn't anymore cover every cases of running breakpoints and vcpu->arch.switch_db_regs might not always be set when the guest used debug registers. (Waiting for a reliable optimization) Changes in v5: - Split-up the asm-generic/hw-breakpoint.h moving to linux/hw_breakpoint.h into a separate patch - Optimize the breakpoints restoring while switching from kvm guest to host. We only want to restore the state if we have active breakpoints to the host, otherwise we don't care about messed-up address registers. - Add asm/hw_breakpoint.h to Kbuild - Fix bad breakpoint type in trace_selftest.c Changes in v6: - Fix wrong header inclusion in trace.h (triggered a build error with CONFIG_FTRACE_SELFTEST Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Prasad <prasad@linux.vnet.ibm.com> Cc: Alan Stern <stern@rowland.harvard.edu> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Ingo Molnar <mingo@elte.hu> Cc: Jan Kiszka <jan.kiszka@web.de> Cc: Jiri Slaby <jirislaby@gmail.com> Cc: Li Zefan <lizf@cn.fujitsu.com> Cc: Avi Kivity <avi@redhat.com> Cc: Paul Mackerras <paulus@samba.org> Cc: Mike Galbraith <efault@gmx.de> Cc: Masami Hiramatsu <mhiramat@redhat.com> Cc: Paul Mundt <lethal@linux-sh.org>
2009-11-03x86: Make sure we also print a Code: line for show_regs()Arjan van de Ven
show_regs() is called as a mini BUG() equivalent in some places, specifically for the "scheduling while atomic" case. Unfortunately right now it does not print a Code: line unlike a real bug/oops. This patch changes the x86 implementation of show_regs() so that it calls the same function as oopses do to print the registers as well as the Code: line. Signed-off-by: Arjan van de Ven <arjan@linux.intel.com> LKML-Reference: <20091102165915.4a980fc0@infradead.org> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-10-12x86: use kernel_stack_pointer() in process_32.cH. Peter Anvin
The way to obtain a kernel-mode stack pointer from a struct pt_regs in 32-bit mode is "subtle": the stack doesn't actually contain the stack pointer, but rather the location where it would have been marks the actual previous stack frame. For clarity, use kernel_stack_pointer() instead of coding this weirdness explicitly. Signed-off-by: H. Peter Anvin <hpa@zytor.com>
2009-09-15Merge branch 'linus' into tracing/hw-breakpointsIngo Molnar
Conflicts: arch/x86/kernel/process_64.c Semantic conflict fixed in: arch/x86/kvm/x86.c Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-09-14Merge branch 'x86-percpu-for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip * 'x86-percpu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: x86, percpu: Collect hot percpu variables into one cacheline x86, percpu: Fix DECLARE/DEFINE_PER_CPU_PAGE_ALIGNED() x86, percpu: Add 'percpu_read_stable()' interface for cacheable accesses
2009-08-04x86, percpu: Collect hot percpu variables into one cachelineTejun Heo
On x86_64, percpu variables current_task and kernel_stack are used for get_current() and current_thread_info() respectively and thus are often used close to each other. Move definition of current_task to kernel/cpu/common.c right above kernel_stack definition and align it to cacheline so that they always fall into the same cacheline. Two percpu variables defined there together - irq_stack_ptr and irq_count - are also pretty hot and will benefit from sharing the cacheline. For consistency, current_task definition for x86_32 is also moved to kernel/cpu/common.c. Putting current_task and kernel_stack into the same cacheline was suggested by Linus Torvalds. Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Ingo Molnar <mingo@elte.hu> Signed-off-by: H. Peter Anvin <hpa@zytor.com>
2009-06-17x86-32: make sure clts is batched during context switchJeremy Fitzhardinge
If we're preloading the fpu state during context switch, make sure the clts happens while we're batching the cpu context update, then do the actual __math_state_restore once the updates are flushed. This allows more efficient context switches when running paravirtualized, as all the hypercalls can be folded together into one. [ Impact: optimise paravirtual FPU context switch ] Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com> Cc: Alok Kataria <akataria@vmware.com> Cc: Rusty Russell <rusty@rustcorp.com.au>
2009-06-17Merge branch 'linus' into tracing/hw-breakpointsIngo Molnar
Conflicts: arch/x86/Kconfig arch/x86/kernel/traps.c arch/x86/power/cpu.c arch/x86/power/cpu_32.c kernel/Makefile Semantic conflict: arch/x86/kernel/hw_breakpoint.c Merge reason: Resolve the conflicts, move from put_cpu_no_sched() to put_cpu() in arch/x86/kernel/hw_breakpoint.c. Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-06-10Merge branch 'tracing-for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip * 'tracing-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: (244 commits) Revert "x86, bts: reenable ptrace branch trace support" tracing: do not translate event helper macros in print format ftrace/documentation: fix typo in function grapher name tracing/events: convert block trace points to TRACE_EVENT(), fix !CONFIG_BLOCK tracing: add protection around module events unload tracing: add trace_seq_vprint interface tracing: fix the block trace points print size tracing/events: convert block trace points to TRACE_EVENT() ring-buffer: fix ret in rb_add_time_stamp ring-buffer: pass in lockdep class key for reader_lock tracing: add annotation to what type of stack trace is recorded tracing: fix multiple use of __print_flags and __print_symbolic tracing/events: fix output format of user stack tracing/events: fix output format of kernel stack tracing/trace_stack: fix the number of entries in the header ring-buffer: discard timestamps that are at the start of the buffer ring-buffer: try to discard unneeded timestamps ring-buffer: fix bug in ring_buffer_discard_commit ftrace: do not profile functions when disabled tracing: make trace pipe recognize latency format flag ...
2009-06-10Merge branch 'x86-xen-for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip * 'x86-xen-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: (42 commits) xen: cache cr0 value to avoid trap'n'emulate for read_cr0 xen/x86-64: clean up warnings about IST-using traps xen/x86-64: fix breakpoints and hardware watchpoints xen: reserve Xen start_info rather than e820 reserving xen: add FIX_TEXT_POKE to fixmap lguest: update lazy mmu changes to match lguest's use of kvm hypercalls xen: honour VCPU availability on boot xen: add "capabilities" file xen: drop kexec bits from /sys/hypervisor since kexec isn't implemented yet xen/sys/hypervisor: change writable_pt to features xen: add /sys/hypervisor support xen/xenbus: export xenbus_dev_changed xen: use device model for suspending xenbus devices xen: remove suspend_cancel hook xen/dev-evtchn: clean up locking in evtchn xen: export ioctl headers to userspace xen: add /dev/xen/evtchn driver xen: add irq_from_evtchn xen: clean up gate trap/interrupt constants xen: set _PAGE_NX in __supported_pte_mask before pagetable construction ...
2009-06-02hw-breakpoints: use the new wrapper routines to access debug registers in ↵K.Prasad
process/thread code This patch enables the use of abstract debug registers in process-handling routines, according to the new hardware breakpoint Api. [ Impact: adapt thread breakpoints handling code to the new breakpoint Api ] Original-patch-by: Alan Stern <stern@rowland.harvard.edu> Signed-off-by: K.Prasad <prasad@linux.vnet.ibm.com> Reviewed-by: Alan Stern <stern@rowland.harvard.edu> Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
2009-05-12x86: process.c, remove useless headersAmerigo Wang
<stdarg.h> is not needed by these files, remove them. [ Impact: cleanup ] Signed-off-by: WANG Cong <amwang@redhat.com> Cc: akpm@linux-foundation.org LKML-Reference: <20090512032956.5040.77055.sendpatchset@localhost.localdomain> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-05-12x86: merge process.c a bitAmerigo Wang
Merge arch_align_stack() and arch_randomize_brk(), since they are the same. Tested on x86_64. [ Impact: cleanup ] Signed-off-by: Amerigo Wang <amwang@redhat.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-04-07Merge commit 'origin/master' into for-linus/xen/masterJeremy Fitzhardinge
* commit 'origin/master': (4825 commits) Fix build errors due to CONFIG_BRANCH_TRACER=y parport: Use the PCI IRQ if offered tty: jsm cleanups Adjust path to gpio headers KGDB_SERIAL_CONSOLE check for module Change KCONFIG name tty: Blackin CTS/RTS Change hardware flow control from poll to interrupt driven Add support for the MAX3100 SPI UART. lanana: assign a device name and numbering for MAX3100 serqt: initial clean up pass for tty side tty: Use the generic RS485 ioctl on CRIS tty: Correct inline types for tty_driver_kref_get() splice: fix deadlock in splicing to file nilfs2: support nanosecond timestamp nilfs2: introduce secondary super block nilfs2: simplify handling of active state of segments nilfs2: mark minor flag for checkpoint created by internal operation nilfs2: clean up sketch file nilfs2: super block operations fix endian bug ... Conflicts: arch/x86/include/asm/thread_info.h arch/x86/lguest/boot.c drivers/xen/manage.c
2009-04-07x86, ds: add leakage warningMarkus Metzger
Add a warning in case a debug store context is not removed before the task it is attached to is freed. Remove the old warning at thread exit. It is too early. Declare the debug store context field in thread_struct unconditionally. Remove ds_copy_thread() and ds_exit_thread() and do the work directly in process*.c. Signed-off-by: Markus Metzger <markus.t.metzger@intel.com> Cc: roland@redhat.com Cc: eranian@googlemail.com Cc: oleg@redhat.com Cc: juan.villacis@intel.com Cc: ak@linux.jf.intel.com LKML-Reference: <20090403144601.254472000@intel.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-04-02Simplify copy_thread()Alexey Dobriyan
First argument unused since 2.3.11. [akpm@linux-foundation.org: coding-style fixes] Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com> Cc: <linux-arch@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-03-29x86/paravirt: finish change from lazy cpu to context switch start/endJeremy Fitzhardinge
Impact: fix lazy context switch API Pass the previous and next tasks into the context switch start end calls, so that the called functions can properly access the task state (esp in end_context_switch, in which the next task is not yet completely current). Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com> Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
2009-03-29x86/pvops: replace arch_enter_lazy_cpu_mode with arch_start_context_switchJeremy Fitzhardinge
Impact: simplification, prepare for later changes Make lazy cpu mode more specific to context switching, so that it makes sense to do more context-switch specific things in the callbacks. Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com> Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
2009-03-02x86: unify chunks of kernel/process*.cJeremy Fitzhardinge
With x86-32 and -64 using the same mechanism for managing the tss io permissions bitmap, large chunks of process*.c are trivially unifyable, including: - exit_thread - flush_thread - __switch_to_xtra (along with tsc enable/disable) and as bonus pickups: - sys_fork - sys_vfork (Note: asmlinkage expands to empty on x86-64) Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-03-02x86-32: use non-lazy io bitmap context switchingJeremy Fitzhardinge
Impact: remove 32-bit optimization to prepare unification x86-32 and -64 differ in the way they context-switch tasks with io permission bitmaps. x86-64 simply copies the next tasks io bitmap into place (if any) on context switch. x86-32 invalidates the bitmap on context switch, so that the next IO instruction will fault; at that point it installs the appropriate IO bitmap. This makes context switching IO-bitmap-using tasks a bit more less expensive, at the cost of making the next IO instruction slower due to the extra fault. This tradeoff only makes sense if IO-bitmap-using processes are relatively common, but they don't actually use IO instructions very often. However, in a typical desktop system, the only process likely to be using IO bitmaps is the X server, and nothing at all on a server. Therefore the lazy context switch doesn't really win all that much, and its just a gratuitious difference from 64-bit code. This patch removes the lazy context switch, with a view to unifying this code in a later change. Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-02-22Merge branch 'linus' into x86/apicIngo Molnar
Conflicts: arch/x86/mach-default/setup.c Semantic conflict resolution: arch/x86/kernel/setup.c Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-02-17x86, rcu: fix strange load average and ksoftirqd behaviorPaul E. McKenney
Damien Wyart reported high ksoftirqd CPU usage (20%) on an otherwise idle system. The function-graph trace Damien provided: > 799.521187 | 1) <idle>-0 | | rcu_check_callbacks() { > 799.521371 | 1) <idle>-0 | | rcu_check_callbacks() { > 799.521555 | 1) <idle>-0 | | rcu_check_callbacks() { > 799.521738 | 1) <idle>-0 | | rcu_check_callbacks() { > 799.521934 | 1) <idle>-0 | | rcu_check_callbacks() { > 799.522068 | 1) ksoftir-2324 | | rcu_check_callbacks() { > 799.522208 | 1) <idle>-0 | | rcu_check_callbacks() { > 799.522392 | 1) <idle>-0 | | rcu_check_callbacks() { > 799.522575 | 1) <idle>-0 | | rcu_check_callbacks() { > 799.522759 | 1) <idle>-0 | | rcu_check_callbacks() { > 799.522956 | 1) <idle>-0 | | rcu_check_callbacks() { > 799.523074 | 1) ksoftir-2324 | | rcu_check_callbacks() { > 799.523214 | 1) <idle>-0 | | rcu_check_callbacks() { > 799.523397 | 1) <idle>-0 | | rcu_check_callbacks() { > 799.523579 | 1) <idle>-0 | | rcu_check_callbacks() { > 799.523762 | 1) <idle>-0 | | rcu_check_callbacks() { > 799.523960 | 1) <idle>-0 | | rcu_check_callbacks() { > 799.524079 | 1) ksoftir-2324 | | rcu_check_callbacks() { > 799.524220 | 1) <idle>-0 | | rcu_check_callbacks() { > 799.524403 | 1) <idle>-0 | | rcu_check_callbacks() { > 799.524587 | 1) <idle>-0 | | rcu_check_callbacks() { > 799.524770 | 1) <idle>-0 | | rcu_check_callbacks() { > [ . . . ] Shows rcu_check_callbacks() being invoked way too often. It should be called once per jiffy, and here it is called no less than 22 times in about 3.5 milliseconds, meaning one call every 160 microseconds or so. Why do we need to call rcu_pending() and rcu_check_callbacks() from the idle loop of 32-bit x86, especially given that no other architecture does this? The following patch removes the call to rcu_pending() and rcu_check_callbacks() from the x86 32-bit idle loop in order to reduce the softirq load on idle systems. Reported-by: Damien Wyart <damien.wyart@free.fr> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-02-11x86: use regparm(3) for passed-in pt_regs pointerBrian Gerst
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>
2009-02-11x86: pass in pt_regs pointer for syscalls that need itBrian Gerst
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>
2009-02-11x86: fix x86_32 stack protector bugsTejun Heo
Impact: fix x86_32 stack protector Brian Gerst found out that %gs was being initialized to stack_canary instead of stack_canary - 20, which basically gave the same canary value for all threads. Fixing this also exposed the following bugs. * cpu_idle() didn't call boot_init_stack_canary() * stack canary switching in switch_to() was being done too late making the initial run of a new thread use the old stack canary value. Fix all of them and while at it update comment in cpu_idle() about calling boot_init_stack_canary(). Reported-by: Brian Gerst <brgerst@gmail.com> Signed-off-by: Tejun Heo <tj@kernel.org> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-02-10x86: implement x86_32 stack protectorTejun Heo
Impact: stack protector for x86_32 Implement stack protector for x86_32. GDT entry 28 is used for it. It's set to point to stack_canary-20 and have the length of 24 bytes. CONFIG_CC_STACKPROTECTOR turns off CONFIG_X86_32_LAZY_GS and sets %gs to the stack canary segment on entry. As %gs is otherwise unused by the kernel, the canary can be anywhere. It's defined as a percpu variable. x86_32 exception handlers take register frame on stack directly as struct pt_regs. With -fstack-protector turned on, gcc copies the whole structure after the stack canary and (of course) doesn't copy back on return thus losing all changed. For now, -fno-stack-protector is added to all files which contain those functions. We definitely need something better. Signed-off-by: Tejun Heo <tj@kernel.org> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-02-10x86: make lazy %gs optional on x86_32Tejun Heo
Impact: pt_regs changed, lazy gs handling made optional, add slight overhead to SAVE_ALL, simplifies error_code path a bit On x86_32, %gs hasn't been used by kernel and handled lazily. pt_regs doesn't have place for it and gs is saved/loaded only when necessary. In preparation for stack protector support, this patch makes lazy %gs handling optional by doing the followings. * Add CONFIG_X86_32_LAZY_GS and place for gs in pt_regs. * Save and restore %gs along with other registers in entry_32.S unless LAZY_GS. Note that this unfortunately adds "pushl $0" on SAVE_ALL even when LAZY_GS. However, it adds no overhead to common exit path and simplifies entry path with error code. * Define different user_gs accessors depending on LAZY_GS and add lazy_save_gs() and lazy_load_gs() which are noop if !LAZY_GS. The lazy_*_gs() ops are used to save, load and clear %gs lazily. * Define ELF_CORE_COPY_KERNEL_REGS() which always read %gs directly. xen and lguest changes need to be verified. Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Jeremy Fitzhardinge <jeremy@xensource.com> Cc: Rusty Russell <rusty@rustcorp.com.au> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-02-10x86: add %gs accessors for x86_32Tejun Heo
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>
2009-01-23x86: remove idle_timestamp from 32bit irq_cpustat_tBrian Gerst
Impact: bogus irq_cpustat field removed idle_timestamp is left over from the removed irqbalance code. Signed-off-by: Brian Gerst <brgerst@gmail.com> Signed-off-by: Tejun Heo <tj@kernel.org>