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* mutexes, sched: Introduce arch_mutex_cpu_relax()Gerald Schaefer2010-11-261-0/+3
| | | | | | | | | | | | | | | | | | The spinning mutex implementation uses cpu_relax() in busy loops as a compiler barrier. Depending on the architecture, cpu_relax() may do more than needed in this specific mutex spin loops. On System z we also give up the time slice of the virtual cpu in cpu_relax(), which prevents effective spinning on the mutex. This patch replaces cpu_relax() in the spinning mutex code with arch_mutex_cpu_relax(), which can be defined by each architecture that selects HAVE_ARCH_MUTEX_CPU_RELAX. The default is still cpu_relax(), so this patch should not affect other architectures than System z for now. Signed-off-by: Gerald Schaefer <gerald.schaefer@de.ibm.com> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> LKML-Reference: <1290437256.7455.4.camel@thinkpad> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* jump label: Add work around to i386 gcc asm goto bugSteven Rostedt2010-10-291-0/+14
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | On i386 (not x86_64) early implementations of gcc would have a bug with asm goto causing it to produce code like the following: (This was noticed by Peter Zijlstra) 56 pushl 0 67 nopl jmp 0x6f popl jmp 0x8c 6f mov test je 0x8c 8c mov call *(%esp) The jump added in the asm goto skipped over the popl that matched the pushl 0, which lead up to a quick crash of the system when the jump was enabled. The nopl is defined in the asm goto () statement and when tracepoints are enabled, the nop changes to a jump to the label that was specified by the asm goto. asm goto is suppose to tell gcc that the code in the asm might jump to an external label. Here gcc obviously fails to make that work. The bug report for gcc is here: http://gcc.gnu.org/bugzilla/show_bug.cgi?id=46226 The bug only appears on x86 when not compiled with -maccumulate-outgoing-args. This option is always set on x86_64 and it is also the work around for a function graph tracer i386 bug. (See commit: 746357d6a526d6da9d89a2ec645b28406e959c2e) This explains why the bug only showed up on i386 when function graph tracer was not enabled. This patch now adds a CONFIG_JUMP_LABEL option that is default off instead of using jump labels by default. When jump labels are enabled, the -maccumulate-outgoing-args will be used (causing a slightly larger kernel image on i386). This option will exist until we have a way to detect if the gcc compiler in use is safe to use on all configurations without the work around. Note, there exists such a test, but for now we will keep the enabling of jump label as a manual option. Archs that know the compiler is safe with asm goto, may choose to select JUMP_LABEL and enable it by default. Reported-by: Ingo Molnar <mingo@elte.hu> Cause-discovered-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Jason Baron <jbaron@redhat.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: David Daney <ddaney@caviumnetworks.com> Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> Cc: David Miller <davem@davemloft.net> Cc: Richard Henderson <rth@redhat.com> LKML-Reference: <1288028746.3673.11.camel@laptop> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
* Merge branch 'tip/perf/core' of ↵Ingo Molnar2010-09-241-0/+3
|\ | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-2.6-trace into perf/core
| * jump label: Base patch for jump labelJason Baron2010-09-221-0/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | base patch to implement 'jump labeling'. Based on a new 'asm goto' inline assembly gcc mechanism, we can now branch to labels from an 'asm goto' statment. This allows us to create a 'no-op' fastpath, which can subsequently be patched with a jump to the slowpath code. This is useful for code which might be rarely used, but which we'd like to be able to call, if needed. Tracepoints are the current usecase that these are being implemented for. Acked-by: David S. Miller <davem@davemloft.net> Signed-off-by: Jason Baron <jbaron@redhat.com> LKML-Reference: <ee8b3595967989fdaf84e698dc7447d315ce972a.1284733808.git.jbaron@redhat.com> [ cleaned up some formating ] Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
* | kprobes: Fix Kconfig dependencyMasami Hiramatsu2010-09-131-2/+2
|/ | | | | | | | | | | | | | | | | | | | | | | | | Fix Kconfig dependency among Kprobes, optprobe and kallsyms. Kprobes uses kallsyms_lookup for finding target function and checking instruction boundary, thus CONFIG_KPROBES should select CONFIG_KALLSYMS. Optprobe is an optional feature which is supported on x86 arch, and it also uses kallsyms_lookup for checking instructions in the target function. Since KALLSYMS_ALL just adds symbols of kernel variables, it doesn't need to select KALLSYMS_ALL. Signed-off-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> Acked-by: Randy Dunlap <randy.dunlap@oracle.com>, Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com> Cc: Felipe Contreras <felipe.contreras@gmail.com> Cc: Randy Dunlap <randy.dunlap@oracle.com> Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com> Cc: Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com> Cc: David S. Miller <davem@davemloft.net> Cc: akpm <akpm@linux-foundation.org> LKML-Reference: <20100913102541.20260.85700.stgit@ltc236.sdl.hitachi.co.jp> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* Merge branch 'perf/nmi' into perf/coreIngo Molnar2010-08-051-0/+7
|\ | | | | | | | | | | | | | | | | Conflicts: kernel/Makefile Merge reason: Add the now complete topic, fix the conflict. Signed-off-by: Ingo Molnar <mingo@elte.hu>
| * lockup_detector: Introduce CONFIG_HARDLOCKUP_DETECTORFrederic Weisbecker2010-05-161-0/+4
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This new config is deemed to simplify even more the lockup detector dependencies and can make it easier to bring a smooth sorting between archs that support the new generic lockup detector and those that still have their own, especially for those that are in the middle of this migration. Instead of checking whether we have CONFIG_LOCKUP_DETECTOR + CONFIG_PERF_EVENTS_NMI each time an arch wants to know if it needs to build its own lockup detector, take a shortcut with this new config. It is enabled only if the hardlockup detection part of the whole lockup detector is on. Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Don Zickus <dzickus@redhat.com> Cc: Cyrill Gorcunov <gorcunov@gmail.com>
| * lockup_detector: Adapt CONFIG_PERF_EVENT_NMI to other archsFrederic Weisbecker2010-05-161-0/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | CONFIG_PERF_EVENT_NMI is something that need to be enabled from the arch. This is fine on x86 as PERF_EVENTS is builtin but if other archs select it, they will need to handle the PERF_EVENTS dependency. Instead, handle the dependency in the generic layer: - archs need to tell what they support through HAVE_PERF_EVENTS_NMI - Enable magically PERF_EVENTS_NMI if we have PERF_EVENTS and HAVE_PERF_EVENTS_NMI. Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Don Zickus <dzickus@redhat.com> Cc: Cyrill Gorcunov <gorcunov@gmail.com>
* | hw-breakpoints: Separate constraint space for data and instruction breakpointsFrederic Weisbecker2010-05-011-0/+11
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | There are two outstanding fashions for archs to implement hardware breakpoints. The first is to separate breakpoint address pattern definition space between data and instruction breakpoints. We then have typically distinct instruction address breakpoint registers and data address breakpoint registers, delivered with separate control registers for data and instruction breakpoints as well. This is the case of PowerPc and ARM for example. The second consists in having merged breakpoint address space definition between data and instruction breakpoint. Address registers can host either instruction or data address and the access mode for the breakpoint is defined in a control register. This is the case of x86 and Super H. This patch adds a new CONFIG_HAVE_MIXED_BREAKPOINTS_REGS config that archs can select if they belong to the second case. Those will have their slot allocation merged for instructions and data breakpoints. The others will have a separate slot tracking between data and instruction breakpoints. Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Acked-by: Paul Mundt <lethal@linux-sh.org> Cc: Will Deacon <will.deacon@arm.com> Cc: Mahesh Salgaonkar <mahesh@linux.vnet.ibm.com> Cc: K. Prasad <prasad@linux.vnet.ibm.com> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Paul Mackerras <paulus@samba.org> Cc: Ingo Molnar <mingo@elte.hu>
* | kprobes: Hide CONFIG_OPTPROBES and set if arch supports optimized kprobesMasami Hiramatsu2010-03-161-7/+2
|/ | | | | | | | | | | | | | | | | | | | | Hide CONFIG_OPTPROBES and set if the arch supports optimized kprobes (IOW, HAVE_OPTPROBES=y), since this option doesn't change the major behavior of kprobes, and workarounds for minor changes are documented. Signed-off-by: Masami Hiramatsu <mhiramat@redhat.com> Cc: systemtap <systemtap@sources.redhat.com> Cc: DLE <dle-develop@lists.sourceforge.net> Cc: Dieter Ries <mail@dieterries.net> Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com> Cc: OGAWA Hirofumi <hirofumi@mail.parknet.co.jp> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Mike Galbraith <efault@gmx.de> Cc: Paul Mackerras <paulus@samba.org> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> LKML-Reference: <20100315170054.31593.3153.stgit@localhost6.localdomain6> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* Merge branch 'perf-probes-for-linus-2' of ↵Linus Torvalds2010-03-051-0/+13
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip * 'perf-probes-for-linus-2' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: x86: Issue at least one memory barrier in stop_machine_text_poke() perf probe: Correct probe syntax on command line help perf probe: Add lazy line matching support perf probe: Show more lines after last line perf probe: Check function address range strictly in line finder perf probe: Use libdw callback routines perf probe: Use elfutils-libdw for analyzing debuginfo perf probe: Rename probe finder functions perf probe: Fix bugs in line range finder perf probe: Update perf probe document perf probe: Do not show --line option without dwarf support kprobes: Add documents of jump optimization kprobes/x86: Support kprobes jump optimization on x86 x86: Add text_poke_smp for SMP cross modifying code kprobes/x86: Cleanup save/restore registers kprobes/x86: Boost probes when reentering kprobes: Jump optimization sysctl interface kprobes: Introduce kprobes jump optimization kprobes: Introduce generic insn_slot framework kprobes/x86: Cleanup RELATIVEJUMP_INSTRUCTION to RELATIVEJUMP_OPCODE
| * kprobes: Introduce kprobes jump optimizationMasami Hiramatsu2010-02-251-0/+13
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Introduce kprobes jump optimization arch-independent parts. Kprobes uses breakpoint instruction for interrupting execution flow, on some architectures, it can be replaced by a jump instruction and interruption emulation code. This gains kprobs' performance drastically. To enable this feature, set CONFIG_OPTPROBES=y (default y if the arch supports OPTPROBE). Changes in v9: - Fix a bug to optimize probe when enabling. - Check nearby probes can be optimize/unoptimize when disarming/arming kprobes, instead of registering/unregistering. This will help kprobe-tracer because most of probes on it are usually disabled. Changes in v6: - Cleanup coding style for readability. - Add comments around get/put_online_cpus(). Changes in v5: - Use get_online_cpus()/put_online_cpus() for avoiding text_mutex deadlock. Signed-off-by: Masami Hiramatsu <mhiramat@redhat.com> Cc: systemtap <systemtap@sources.redhat.com> Cc: DLE <dle-develop@lists.sourceforge.net> Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com> Cc: Jim Keniston <jkenisto@us.ibm.com> Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com> Cc: Christoph Hellwig <hch@infradead.org> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Anders Kaseorg <andersk@ksplice.com> Cc: Tim Abbott <tabbott@ksplice.com> Cc: Andi Kleen <andi@firstfloor.org> Cc: Jason Baron <jbaron@redhat.com> Cc: Mathieu Desnoyers <compudj@krystal.dyndns.org> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com> LKML-Reference: <20100225133407.6725.81992.stgit@localhost6.localdomain6> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* | Merge branch 'tracing-core-for-linus' of ↵Linus Torvalds2010-02-281-0/+8
|\ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip * 'tracing-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: (28 commits) ftrace: Add function names to dangling } in function graph tracer tracing: Simplify memory recycle of trace_define_field tracing: Remove unnecessary variable in print_graph_return tracing: Fix typo of info text in trace_kprobe.c tracing: Fix typo in prof_sysexit_enable() tracing: Remove CONFIG_TRACE_POWER from kernel config tracing: Fix ftrace_event_call alignment for use with gcc 4.5 ftrace: Remove memory barriers from NMI code when not needed tracing/kprobes: Add short documentation for HAVE_REGS_AND_STACK_ACCESS_API s390: Add pt_regs register and stack access API tracing/kprobes: Make Kconfig dependencies generic tracing: Unify arch_syscall_addr() implementations tracing: Add notrace to TRACE_EVENT implementation functions ftrace: Allow to remove a single function from function graph filter tracing: Add correct/incorrect to sort keys for branch annotation output tracing: Simplify test for function_graph tracing start point tracing: Drop the tr check from the graph tracing path tracing: Add stack dump to trace_printk if stacktrace option is set tracing: Use appropriate perl constructs in recordmcount.pl tracing: optimize recordmcount.pl for offsets-handling ...
| * | tracing/kprobes: Add short documentation for HAVE_REGS_AND_STACK_ACCESS_APIHeiko Carstens2010-02-221-0/+5
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | So that arch developers know how to implement it without the need to dig into changelogs. Reported-by: Mike Frysinger <vapier.adi@gmail.com> Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com> Acked-by: Masami Hiramatsu <mhiramat@redhat.com> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: "David S . Miller" <davem@davemloft.net> Cc: Paul Mundt <lethal@linux-sh.org> Cc: Steven Rostedt <rostedt@goodmis.org> LKML-Reference: <20100218132521.GB2406@osiris.boeblingen.de.ibm.com> [added reference to ptrace.h in the config help] Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
| * | tracing/kprobes: Make Kconfig dependencies genericHeiko Carstens2010-02-171-0/+3
| |/ | | | | | | | | | | | | | | | | | | | | | | | | | | KPROBES_EVENT actually depends on the regs and stack access API (b1cf540f) and not on x86. So introduce a new config option which architectures can select if they have the API implemented and switch x86. Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com> Acked-by: Masami Hiramatsu <mhiramat@redhat.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> LKML-Reference: <20100210162517.GB6933@osiris.boeblingen.de.ibm.com> Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
* | oprofile/x86: remove OPROFILE_IBS config optionRobert Richter2010-02-261-14/+0
| | | | | | | | | | | | | | | | | | | | OProfile support for IBS is now for several versions in the kernel. The feature is stable now and the code can be activated permanently. As a side effect IBS now works also on nosmp configs. Signed-off-by: Robert Richter <robert.richter@amd.com>
* | oprofile: remove EXPERIMENTAL from the config option descriptionRobert Richter2010-02-261-1/+1
| | | | | | | | | | | | OProfile is already used for a long time and no longer experimental. Signed-off-by: Robert Richter <robert.richter@amd.com>
* | oprofile: remove tracing build dependencyRobert Richter2010-02-261-2/+0
|/ | | | | | | | | | | | | | | | | The commit 1155de4 ring-buffer: Make it generally available already made ring-buffer available without the TRACING option enabled. This patch removes the TRACING dependency from oprofile. Fixes also oprofile configuration on ia64. The patch also applies to the 2.6.32-stable kernel. Reported-by: Tony Jones <tonyj@suse.de> Cc: stable@kernel.org Signed-off-by: Robert Richter <robert.richter@amd.com>
* hw-breakpoints: Fix hardware breakpoints -> perf events dependencyFrederic Weisbecker2009-12-181-3/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The kbuild's select command doesn't propagate through the config dependencies. Hence the current rules of hardware breakpoint's config can't ensure perf can never be disabled under us. We have: config X86 selects HAVE_HW_BREAKPOINTS config HAVE_HW_BREAKPOINTS select PERF_EVENTS config PERF_EVENTS [...] x86 will select the breakpoints but that won't propagate to perf events. The user can still disable the latter, but it is necessary for the breakpoints. What we need is: - x86 selects HAVE_HW_BREAKPOINTS and PERF_EVENTS - HAVE_HW_BREAKPOINTS depends on PERF_EVENTS so that we ensure PERF_EVENTS is enabled and frozen for x86. This fixes the following kind of build errors: In file included from arch/x86/kernel/hw_breakpoint.c:31: include/linux/hw_breakpoint.h: In function 'hw_breakpoint_addr': include/linux/hw_breakpoint.h:39: error: 'struct perf_event' has no member named 'attr' v2: Select also ANON_INODES from x86, required for perf Reported-by: Cyrill Gorcunov <gorcunov@gmail.com> Reported-by: Michal Marek <mmarek@suse.cz> Reported-by: Andrew Randrianasulu <randrik_a@yahoo.com> Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Paul Mackerras <paulus@samba.org> Cc: Randy Dunlap <randy.dunlap@oracle.com> Cc: K.Prasad <prasad@linux.vnet.ibm.com> LKML-Reference: <1261010034-7786-1-git-send-regression-fweisbec@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* Merge branch 'kvm-updates/2.6.33' of git://git.kernel.org/pub/scm/virt/kvm/kvmLinus Torvalds2009-12-081-0/+9
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | * 'kvm-updates/2.6.33' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (84 commits) KVM: VMX: Fix comparison of guest efer with stale host value KVM: s390: Fix prefix register checking in arch/s390/kvm/sigp.c KVM: Drop user return notifier when disabling virtualization on a cpu KVM: VMX: Disable unrestricted guest when EPT disabled KVM: x86 emulator: limit instructions to 15 bytes KVM: s390: Make psw available on all exits, not just a subset KVM: x86: Add KVM_GET/SET_VCPU_EVENTS KVM: VMX: Report unexpected simultaneous exceptions as internal errors KVM: Allow internal errors reported to userspace to carry extra data KVM: Reorder IOCTLs in main kvm.h KVM: x86: Polish exception injection via KVM_SET_GUEST_DEBUG KVM: only clear irq_source_id if irqchip is present KVM: x86: disallow KVM_{SET,GET}_LAPIC without allocated in-kernel lapic KVM: x86: disallow multiple KVM_CREATE_IRQCHIP KVM: VMX: Remove vmx->msr_offset_efer KVM: MMU: update invlpg handler comment KVM: VMX: move CR3/PDPTR update to vmx_set_cr3 KVM: remove duplicated task_switch check KVM: powerpc: Fix BUILD_BUG_ON condition KVM: VMX: Use shared msr infrastructure ... Trivial conflicts due to new Kconfig options in arch/Kconfig and kernel/Makefile
| * core, x86: Add user return notifiersAvi Kivity2009-10-011-0/+10
| | | | | | | | | | | | | | | | | | | | | | | | | | | | Add a general per-cpu notifier that is called whenever the kernel is about to return to userspace. The notifier uses a thread_info flag and existing checks, so there is no impact on user return or context switch fast paths. This will be used initially to speed up KVM task switching by lazily updating MSRs. Signed-off-by: Avi Kivity <avi@redhat.com> LKML-Reference: <1253342422-13811-1-git-send-email-avi@redhat.com> Signed-off-by: H. Peter Anvin <hpa@zytor.com>
* | hw-breakpoints: Rewrite the hw-breakpoints layer on top of perf eventsFrederic Weisbecker2009-11-081-0/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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>
* | Merge commit 'perf/core' into perf/hw-breakpointFrederic Weisbecker2009-10-181-0/+1
|\ \ | |/ | | | | | | | | | | | | | | | | | | | | Conflicts: kernel/Makefile kernel/trace/Makefile kernel/trace/trace.h samples/Makefile Merge reason: We need to be uptodate with the perf events development branch because we plan to rewrite the breakpoints API on top of perf events.
| * oprofile: fix oprofile regression: select RING_BUFFER_ALLOW_SWAPChristian Borntraeger2009-09-171-0/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | commit 85bac32c4a52c592b857f2c360cc5ec93a097d70 ring-buffer: only enable ring_buffer_swap_cpu when needed broke oprofile (at least on s390, but likely on all platforms). this patch lets oprofile select RING_BUFER_ALLOW_SWAP to make ring_buffer_swap_cpu usable for oprofile. Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com> LKML-Reference: <200909162156.49239.borntraeger@de.ibm.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Robert Richter <robert.richter@amd.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
* | Merge branch 'linus' into tracing/hw-breakpointsIngo Molnar2009-09-151-0/+12
|\ \ | |/ | | | | | | | | | | | | | | | | Conflicts: arch/x86/kernel/process_64.c Semantic conflict fixed in: arch/x86/kvm/x86.c Signed-off-by: Ingo Molnar <mingo@elte.hu>
| * oprofile: Implement performance counter multiplexingJason Yeh2009-07-201-0/+12
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The number of hardware counters is limited. The multiplexing feature enables OProfile to gather more events than counters are provided by the hardware. This is realized by switching between events at an user specified time interval. A new file (/dev/oprofile/time_slice) is added for the user to specify the timer interval in ms. If the number of events to profile is higher than the number of hardware counters available, the patch will schedule a work queue that switches the event counter and re-writes the different sets of values into it. The switching mechanism needs to be implemented for each architecture to support multiplexing. This patch only implements AMD CPU support, but multiplexing can be easily extended for other models and architectures. There are follow-on patches that rework parts of this patch. Signed-off-by: Jason Yeh <jason.yeh@amd.com> Signed-off-by: Robert Richter <robert.richter@amd.com>
* | Merge branch 'tracing/core' into tracing/hw-breakpointsIngo Molnar2009-09-071-0/+2
|\ \ | |/ | | | | | | | | | | | | | | | | | | Conflicts: arch/Kconfig kernel/trace/trace.h Merge reason: resolve the conflicts, plus adopt to the new ring-buffer APIs. Signed-off-by: Ingo Molnar <mingo@elte.hu>
| * gcov: add gcov profiling infrastructurePeter Oberparleiter2009-06-181-0/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Enable the use of GCC's coverage testing tool gcov [1] with the Linux kernel. gcov may be useful for: * debugging (has this code been reached at all?) * test improvement (how do I change my test to cover these lines?) * minimizing kernel configurations (do I need this option if the associated code is never run?) The profiling patch incorporates the following changes: * change kbuild to include profiling flags * provide functions needed by profiling code * present profiling data as files in debugfs Note that on some architectures, enabling gcc's profiling option "-fprofile-arcs" for the entire kernel may trigger compile/link/ run-time problems, some of which are caused by toolchain bugs and others which require adjustment of architecture code. For this reason profiling the entire kernel is initially restricted to those architectures for which it is known to work without changes. This restriction can be lifted once an architecture has been tested and found compatible with gcc's profiling. Profiling of single files or directories is still available on all platforms (see config help text). [1] http://gcc.gnu.org/onlinedocs/gcc/Gcov.html Signed-off-by: Peter Oberparleiter <oberpar@linux.vnet.ibm.com> Cc: Andi Kleen <andi@firstfloor.org> Cc: Huang Ying <ying.huang@intel.com> Cc: Li Wei <W.Li@Sun.COM> Cc: Michael Ellerman <michaele@au1.ibm.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Heiko Carstens <heicars2@linux.vnet.ibm.com> Cc: Martin Schwidefsky <mschwid2@linux.vnet.ibm.com> Cc: Rusty Russell <rusty@rustcorp.com.au> Cc: WANG Cong <xiyou.wangcong@gmail.com> Cc: Sam Ravnborg <sam@ravnborg.org> Cc: Jeff Dike <jdike@addtoit.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | hw-breakpoints: introducing generic hardware breakpoint handler interfacesK.Prasad2009-06-021-0/+4
|/ | | | | | | | | | | | | | | | | | | | | | | | | | | | This patch introduces the generic Hardware Breakpoint interfaces for both user and kernel space requests. This core Api handles the hardware breakpoints through new helpers. It handles the user-space breakpoints and kernel breakpoints in front of arch implementation. One can choose kernel wide breakpoints using the following helpers and passing them a generic struct hw_breakpoint: - register_kernel_hw_breakpoint() - unregister_kernel_hw_breakpoint() - modify_kernel_hw_breakpoint() On the other side, you can choose per task breakpoints. - register_user_hw_breakpoint() - unregister_user_hw_breakpoint() - modify_user_hw_breakpoint() [ fweisbec@gmail.com: fix conflict against perfcounter ] 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>
* mutex: have non-spinning mutexes on s390 by defaultHeiko Carstens2009-04-091-0/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | Impact: performance regression fix for s390 The adaptive spinning mutexes will not always do what one would expect on virtualized architectures like s390. Especially the cpu_relax() loop in mutex_spin_on_owner might hurt if the mutex holding cpu has been scheduled away by the hypervisor. We would end up in a cpu_relax() loop when there is no chance that the state of the mutex changes until the target cpu has been scheduled again by the hypervisor. For that reason we should change the default behaviour to no-spin on s390. We do have an instruction which allows to yield the current cpu in favour of a different target cpu. Also we have an instruction which allows us to figure out if the target cpu is physically backed. However we need to do some performance tests until we can come up with a solution that will do the right thing on s390. Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com> Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Christian Borntraeger <borntraeger@de.ibm.com> LKML-Reference: <20090409184834.7a0df7b2@osiris.boeblingen.de.ibm.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* Merge branch 'tracing/core-v2' into tracing-for-linusIngo Molnar2009-04-021-0/+1
|\ | | | | | | | | | | | | | | Conflicts: include/linux/slub_def.h lib/Kconfig.debug mm/slob.c mm/slub.c
| * tracing: clean up menuIngo Molnar2009-03-051-0/+1
| | | | | | | | | | | | | | Clean up menu structure, introduce TRACING_SUPPORT switch that signals whether an architecture supports various instrumentation mechanisms. Signed-off-by: Ingo Molnar <mingo@elte.hu>
* | dma-debug: add Kconfig entryJoerg Roedel2009-03-051-0/+2
|/ | | | | | Impact: add a Kconfig entry for DMA-API debugging Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
* [CVE-2009-0029] System call wrapper infrastructureHeiko Carstens2009-01-141-0/+3
| | | | | | | | | | | | | | | From: Martin Schwidefsky <schwidefsky@de.ibm.com> By selecting HAVE_SYSCALL_WRAPPERS architectures can activate system call wrappers in order to sign extend system call arguments. All architectures where the ABI defines that the caller of a function has to perform sign extension probably need this. Reported-by: Christian Borntraeger <borntraeger@de.ibm.com> Acked-by: Ralf Baechle <ralf@linux-mips.org> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com> Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
* oprofile: select RING_BUFFERIngo Molnar2008-12-121-0/+2
| | | | | | | | | | | | | Impact: build fix OProfile now depends on the ring buffer infrastructure: arch/x86/oprofile/built-in.o: In function `oprofile_add_ibs_sample': : undefined reference to `ring_buffer_unlock_commit' Select TRACING and RING_BUFFER when oprofile is enabled. Signed-off-by: Ingo Molnar <mingo@elte.hu>
* remove __ARCH_WANT_COMPAT_SYS_PTRACEChristoph Hellwig2008-11-301-2/+0
| | | | | | | | | | | | | All architectures now use the generic compat_sys_ptrace, as should every new architecture that needs 32bit compat (if we'll ever get another). Remove the now superflous __ARCH_WANT_COMPAT_SYS_PTRACE define, and also kill a comment about __ARCH_SYS_PTRACE that was added after __ARCH_SYS_PTRACE was already gone. Signed-off-by: Christoph Hellwig <hch@lst.de> Acked-by: David S. Miller <davem@davemloft.net> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* Change UTF8 chars in Kconfig help text about Oprofile AMD barcelonaJesper Dangaard Brouer2008-10-271-1/+1
| | | | | | | | | | | | Fixes screwing up text output when doing a make oldconfig and viewing help text of "OProfile AMD IBS support". When the terminal is not using an UTF8 locale / LANG. "make config" breaks terminal output and its not possible to continue. (Change added by changeset 852402cc Tue Jul 22 21:09:06 2008) Signed-off-by: Jesper Dangaard Brouer <hawk@comx.dk> Signed-off-by: Robert Richter <robert.richter@amd.com>
* Kconfig: eliminate "def_bool n" constructsJan Beulich2008-10-161-9/+9
| | | | | | | | | | | | | | | | | Using "def_bool n" is pointless, simply using bool here appears more appropriate. Further, retaining such options that don't have a prompt and aren't selected by anything seems also at least questionable. Signed-off-by: Jan Beulich <jbeulich@novell.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Tony Luck <tony.luck@intel.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com> Cc: Sam Ravnborg <sam@ravnborg.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* Merge branch 'linus' into oprofile-v2Ingo Molnar2008-10-131-0/+18
|\ | | | | | | | | | | | | Conflicts: arch/x86/kernel/apic_32.c arch/x86/oprofile/nmi_int.c include/linux/pci_ids.h
| * tracehook: CONFIG_HAVE_ARCH_TRACEHOOKRoland McGrath2008-07-261-0/+18
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This adds the generic HAVE_ARCH_TRACEHOOK kconfig item. Each arch should add to some Kconfig file: select HAVE_ARCH_TRACEHOOK if the arch code uses all the latest hooks to enable newfangled tracing and debugging code. The comment in arch/Kconfig lists all the prerequisite arch support. When all these are available, setting HAVE_ARCH_TRACEHOOK will allow enabling any new features that depend on the modern arch interfaces. Signed-off-by: Roland McGrath <roland@redhat.com> Cc: Oleg Nesterov <oleg@tv-sign.ru> Reviewed-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | x86/oprofile: add CONFIG_OPROFILE_IBS optionRobert Richter2008-07-261-0/+14
|/ | | | | | | | Signed-off-by: Robert Richter <robert.richter@amd.com> Cc: oprofile-list <oprofile-list@lists.sourceforge.net> Cc: Robert Richter <robert.richter@amd.com> Cc: Barry Kasindorf <barry.kasindorf@amd.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* introduce HAVE_EFFICIENT_UNALIGNED_ACCESS Kconfig symbolJohannes Berg2008-07-251-0/+19
| | | | | | | | | | | | | | | | | | | In many cases, especially in networking, it can be beneficial to know at compile time whether the architecture can do unaligned accesses efficiently. This patch introduces a new Kconfig symbol HAVE_EFFICIENT_UNALIGNED_ACCESS for that purpose and adds it to the powerpc and x86 architectures. Also add some documentation about alignment and networking, and especially one intended use of this symbol. Signed-off-by: Johannes Berg <johannes@sipsolutions.net> Acked-by: Sam Ravnborg <sam@ravnborg.org> Acked-by: Ingo Molnar <mingo@elte.hu> [x86 architecture part] Cc: <linux-arch@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* access_process_vm device memory infrastructureRik van Riel2008-07-241-0/+3
| | | | | | | | | | | | | | | | | | | | | | In order to be able to debug things like the X server and programs using the PPC Cell SPUs, the debugger needs to be able to access device memory through ptrace and /proc/pid/mem. This patch: Add the generic_access_phys access function and put the hooks in place to allow access_process_vm to access device or PPC Cell SPU memory. [riel@redhat.com: Add documentation for the vm_ops->access function] Signed-off-by: Rik van Riel <riel@redhat.com> Signed-off-by: Benjamin Herrensmidt <benh@kernel.crashing.org> Cc: Dave Airlie <airlied@linux.ie> Cc: Hugh Dickins <hugh@veritas.com> Cc: Paul Mackerras <paulus@samba.org> Cc: Arnd Bergmann <arnd@arndb.de> Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* add HAVE_CLK to Kconfig, for driver dependenciesDavid Brownell2008-07-241-0/+7
| | | | | | | | | | | | | | | | | | | | Flag platforms as HAVE_CLK (or not) in Kconfig, based on whether they support <linux/clk.h> calls, so that otherwise portable drivers which need those calls can list that dependency. Something like this is a prerequisite for merging the musb_hdrc driver, currently used on platforms including Davinci, OMAP2430, OMAP3xx ... and the discrete TUSB6010 chip, which doesn't have a natural platform dependency. (Used with OMAP 2420 in current Nokia N8x0 tablets.) Signed-off-by: David Brownell <dbrownell@users.sourceforge.net> Cc: Russell King <rmk@arm.linux.org.uk> Acked-by: Haavard Skinnemoen <hskinnemoen@atmel.com> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Paul Mackerras <paulus@samba.org> Cc: Paul Mundt <lethal@linux-sh.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* Add generic helpers for arch IPI function callsJens Axboe2008-06-261-0/+3
| | | | | | | | | | | | | | | | | This adds kernel/smp.c which contains helpers for IPI function calls. In addition to supporting the existing smp_call_function() in a more efficient manner, it also adds a more scalable variant called smp_call_function_single() for calling a given function on a single CPU only. The core of this is based on the x86-64 patch from Nick Piggin, lots of changes since then. "Alan D. Brunelle" <Alan.Brunelle@hp.com> has contributed lots of fixes and suggestions as well. Also thanks to Paul E. McKenney <paulmck@linux.vnet.ibm.com> for reviewing RCU usage and getting rid of the data allocation fallback deadlock. Acked-by: Ingo Molnar <mingo@elte.hu> Reviewed-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
* dma: add dma_*map*_attrs() interfacesArthur Kepner2008-04-291-0/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | Introduce new interfaces, dma_*map*_attrs(), for passing architecture-specific attributes when memory is mapped and unmapped for DMA. Give the interfaces default implementations which ignore attributes. Also introduce the dma_{set|get}_attr() interfaces for setting and retrieving individual attributes. Define one attribute, DMA_ATTR_WRITE_BARRIER, in anticipation of its use by ia64/sn. Select whether architectures implement arch-specific versions of the dma_*map*_attrs() interfaces via HAVE_DMA_ATTRS in Kconfig. [markn@au1.ibm.com: dma_{set,get}_attr() have to be static inline] Signed-off-by: Arthur Kepner <akepner@sgi.com> Cc: Tony Luck <tony.luck@intel.com> Cc: Jesse Barnes <jbarnes@virtuousgeek.org> Cc: Jes Sorensen <jes@sgi.com> Cc: Randy Dunlap <randy.dunlap@oracle.com> Cc: Roland Dreier <rdreier@cisco.com> Cc: James Bottomley <James.Bottomley@HansenPartnership.com> Cc: David Miller <davem@davemloft.net> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Grant Grundler <grundler@parisc-linux.org> Cc: Michael Ellerman <michael@ellerman.id.au> Signed-off-by: Mark Nelson <markn@au1.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* Kprobes: indicate kretprobe support in KconfigAnanth N Mavinakayanahalli2008-03-041-0/+7
| | | | | | | | | | | | | | | | | Add CONFIG_HAVE_KRETPROBES to the arch/<arch>/Kconfig file for relevant architectures with kprobes support. This facilitates easy handling of in-kernel modules (like samples/kprobes/kretprobe_example.c) that depend on kretprobes being present in the kernel. Thanks to Sam Ravnborg for helping make the patch more lean. Per Mathieu's suggestion, added CONFIG_KRETPROBES and fixed up dependencies. Signed-off-by: Ananth N Mavinakayanahalli <ananth@in.ibm.com> Acked-by: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca> Acked-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* Move Kconfig.instrumentation to arch/Kconfig and init/KconfigMathieu Desnoyers2008-02-031-0/+28
| | | | | | | | | | | | | | | | | | | | | | Move the instrumentation Kconfig to arch/Kconfig for architecture dependent options - oprofile - kprobes and init/Kconfig for architecture independent options - profiling - markers Remove the "Instrumentation Support" menu. Everything moves to "General setup". Delete the kernel/Kconfig.instrumentation file. Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: <linux-arch@vger.kernel.org> Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
* Create arch/KconfigMathieu Desnoyers2008-02-031-0/+3
Puts the content of arch/Kconfig in the "General setup" menu. Linus: > Should it come with a re-duplication of it's content into each > architecture, which was the case previously ? The oprofile and kprobes > menu entries were litteraly cut and pasted from one architecture to > another. Should we put its content in init/Kconfig then ? I don't think it's a good idea to go back to making it per-architecture, although that extensive "depends on <list-of-archiectures-here>" might indicate that there certainly is room for cleanup there. And I don't think it's wrong keeping it in kernel/Kconfig.xyz per se, I just think it's wrong to (a) lump the code together when it really doesn't necessarily need to and (b) show it to users as some kind of choice that is tied together (whether it then has common code or not). On the per-architecture side, I do think it would be better to *not* have internal architecture knowledge in a generic file, and as such a line like depends on X86_32 || IA64 || PPC || S390 || SPARC64 || X86_64 || AVR32 really shouldn't exist in a file like kernel/Kconfig.instrumentation. It would be much better to do depends on ARCH_SUPPORTS_KPROBES in that generic file, and then architectures that do support it would just have a bool ARCH_SUPPORTS_KPROBES default y in *their* architecture files. That would seem to be much more logical, and is readable both for arch maintainers *and* for people who have no clue - and don't care - about which architecture is supposed to support which interface... Sam Ravnborg: Stuff it into a new file: arch/Kconfig We can then extend this file to include all the 'trailing' Kconfig things that are anyway equal for all ARCHs. But it should be kept clean - so if we introduce such a file then we should use ARCH_HAS_whatever in the arch specific Kconfig files to enable stuff that is not shared. [...] The above suggestion is actually not exactly the best way to do it... First the naming.. A quick grep shows following usage today (in Kconfig files) ARCH_HAS 51 ARCH_SUPPORTS 4 HAVE_ARCH 7 ARCH_HAS is the clear winner. In the common Kconfig file do: config FOO depends on ARCH_HAS_FOO bool "bla bla" config ARCH_HAS_FOO def_bool n In the arch specific Kconfig file in a suitable place do: config SUITABLE_OPTION select ARCH_HAS_FOO The naming of ARCH_HAS_ is fixed and shall be: ARCH_HAS_<config option it will enable> Only a single line added pr. architecture. And we will end up with a (maybe even commented) list of trivial selects. - Yet another update : Moving to HAVE_* now. Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca> Cc: Jeff Dike <jdike@addtoit.com> Cc: David Howells <dhowells@redhat.com> Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com> Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
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