Commit graph

50 commits

Author SHA1 Message Date
Justin P. Mattock
6875669906 arch:Kconfig.locks Remove unused config option.
Signed-off-by: Justin P. Mattock <justinmattock@gmail.com>
Acked-by: Steven Rostedt <rostedt@goodmis.org>
Acked-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
2011-04-10 17:01:05 +02:00
Gerald Schaefer
335d7afbfb mutexes, sched: Introduce arch_mutex_cpu_relax()
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>
2010-11-26 15:05:34 +01:00
Steven Rostedt
45f81b1c96 jump label: Add work around to i386 gcc asm goto bug
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: 746357d6a5)
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>
2010-10-29 14:45:29 -04:00
Ingo Molnar
a5a2bad55d Merge branch 'tip/perf/core' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-2.6-trace into perf/core 2010-09-24 09:12:05 +02:00
Jason Baron
bf5438fca2 jump label: Base patch for jump label
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>
2010-09-22 16:29:41 -04:00
Masami Hiramatsu
05ed160e89 kprobes: Fix Kconfig dependency
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>
2010-09-13 20:41:31 +02:00
Ingo Molnar
61be7fdec2 Merge branch 'perf/nmi' into perf/core
Conflicts:
	kernel/Makefile

Merge reason: Add the now complete topic, fix the conflict.

Signed-off-by: Ingo Molnar <mingo@elte.hu>
2010-08-05 08:45:05 +02:00
Frederic Weisbecker
23637d477c lockup_detector: Introduce CONFIG_HARDLOCKUP_DETECTOR
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>
2010-05-16 01:57:42 +02:00
Frederic Weisbecker
c01d432330 lockup_detector: Adapt CONFIG_PERF_EVENT_NMI to other archs
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>
2010-05-16 01:57:36 +02:00
Frederic Weisbecker
0102752e4c hw-breakpoints: Separate constraint space for data and instruction breakpoints
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>
2010-05-01 04:32:11 +02:00
Masami Hiramatsu
5cc718b9da kprobes: Hide CONFIG_OPTPROBES and set if arch supports optimized kprobes
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>
2010-03-16 11:07:23 +01:00
Linus Torvalds
660f6a360b Merge branch 'perf-probes-for-linus-2' of 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
2010-03-05 10:50:22 -08:00
Linus Torvalds
e0d272429a Merge branch 'tracing-core-for-linus' of 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
  ...
2010-02-28 10:17:55 -08:00
Robert Richter
013cfc5067 oprofile/x86: remove OPROFILE_IBS config option
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>
2010-02-26 15:13:55 +01:00
Robert Richter
b309a294e5 oprofile: remove EXPERIMENTAL from the config option description
OProfile is already used for a long time and no longer experimental.

Signed-off-by: Robert Richter <robert.richter@amd.com>
2010-02-26 15:13:54 +01:00
Robert Richter
18b4a4d59e oprofile: remove tracing build dependency
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>
2010-02-26 14:52:52 +01:00
Masami Hiramatsu
afd66255b9 kprobes: Introduce kprobes jump optimization
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>
2010-02-25 17:49:24 +01:00
Heiko Carstens
e01292b1fd tracing/kprobes: Add short documentation for HAVE_REGS_AND_STACK_ACCESS_API
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>
2010-02-22 17:05:51 +01:00
Heiko Carstens
f850c30c8b tracing/kprobes: Make Kconfig dependencies generic
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>
2010-02-17 13:13:08 +01:00
Frederic Weisbecker
99e8c5a3b8 hw-breakpoints: Fix hardware breakpoints -> perf events dependency
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>
2009-12-18 13:11:51 +01:00
Linus Torvalds
ed9216c171 Merge branch 'kvm-updates/2.6.33' of git://git.kernel.org/pub/scm/virt/kvm/kvm
* '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
2009-12-08 08:02:38 -08:00
Frederic Weisbecker
24f1e32c60 hw-breakpoints: Rewrite the hw-breakpoints layer on top of perf events
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>
2009-11-08 15:34:42 +01:00
Frederic Weisbecker
0f8f86c7bd Merge commit 'perf/core' into perf/hw-breakpoint
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.
2009-10-18 01:12:33 +02:00
Avi Kivity
7c68af6e32 core, x86: Add user return notifiers
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>
2009-10-01 12:12:18 -07:00
Christian Borntraeger
9a5963eb49 oprofile: fix oprofile regression: select RING_BUFFER_ALLOW_SWAP
commit 85bac32c4a
    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>
2009-09-17 15:53:42 -04:00
Ingo Molnar
dca2d6ac09 Merge branch 'linus' into tracing/hw-breakpoints
Conflicts:
	arch/x86/kernel/process_64.c

Semantic conflict fixed in:
	arch/x86/kvm/x86.c

Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-09-15 12:18:15 +02:00
Ingo Molnar
a1922ed661 Merge branch 'tracing/core' into tracing/hw-breakpoints
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>
2009-09-07 08:19:51 +02:00
Jason Yeh
4d4036e0e7 oprofile: Implement performance counter multiplexing
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>
2009-07-20 16:33:53 +02:00
Peter Oberparleiter
2521f2c228 gcov: add gcov profiling infrastructure
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>
2009-06-18 13:03:57 -07:00
K.Prasad
62a038d34d hw-breakpoints: introducing generic hardware breakpoint handler interfaces
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>
2009-06-02 22:46:58 +02:00
Heiko Carstens
36cd3c9f92 mutex: have non-spinning mutexes on s390 by default
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>
2009-04-09 19:28:24 +02:00
Ingo Molnar
8302294f43 Merge branch 'tracing/core-v2' into tracing-for-linus
Conflicts:
	include/linux/slub_def.h
	lib/Kconfig.debug
	mm/slob.c
	mm/slub.c
2009-04-02 00:49:02 +02:00
Ingo Molnar
40ada30f96 tracing: clean up menu
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>
2009-03-05 21:53:25 +01:00
Joerg Roedel
5ee00bd469 dma-debug: add Kconfig entry
Impact: add a Kconfig entry for DMA-API debugging

Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
2009-03-05 14:36:50 +01:00
Heiko Carstens
1a94bc3476 [CVE-2009-0029] System call wrapper infrastructure
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>
2009-01-14 14:15:16 +01:00
Ingo Molnar
d69d59f497 oprofile: select RING_BUFFER
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>
2008-12-12 09:46:31 +01:00
Christoph Hellwig
96b8936a9e remove __ARCH_WANT_COMPAT_SYS_PTRACE
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>
2008-11-30 11:00:15 -08:00
Jesper Dangaard Brouer
ba8b453de0 Change UTF8 chars in Kconfig help text about Oprofile AMD barcelona
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>
2008-10-27 19:15:39 +01:00
Jan Beulich
9ba16087d9 Kconfig: eliminate "def_bool n" constructs
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>
2008-10-16 11:21:31 -07:00
Ingo Molnar
accba5f396 Merge branch 'linus' into oprofile-v2
Conflicts:
	arch/x86/kernel/apic_32.c
	arch/x86/oprofile/nmi_int.c
	include/linux/pci_ids.h
2008-10-13 11:05:51 +02:00
Roland McGrath
1f5a4ad97a tracehook: CONFIG_HAVE_ARCH_TRACEHOOK
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>
2008-07-26 12:00:09 -07:00
Robert Richter
852402cc27 x86/oprofile: add CONFIG_OPROFILE_IBS option
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>
2008-07-26 11:48:13 +02:00
Johannes Berg
58340a07c1 introduce HAVE_EFFICIENT_UNALIGNED_ACCESS Kconfig symbol
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>
2008-07-25 10:53:27 -07:00
Rik van Riel
28b2ee20c7 access_process_vm device memory infrastructure
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>
2008-07-24 10:47:15 -07:00
David Brownell
9483a578df add HAVE_CLK to Kconfig, for driver dependencies
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>
2008-07-24 10:47:13 -07:00
Jens Axboe
3d44223327 Add generic helpers for arch IPI function calls
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>
2008-06-26 11:21:34 +02:00
Arthur Kepner
74bc7ceebf dma: add dma_*map*_attrs() interfaces
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>
2008-04-29 08:06:11 -07:00
Ananth N Mavinakayanahalli
9edddaa200 Kprobes: indicate kretprobe support in Kconfig
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>
2008-03-04 16:35:11 -08:00
Mathieu Desnoyers
125e564582 Move Kconfig.instrumentation to arch/Kconfig and init/Kconfig
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>
2008-02-03 08:58:08 +01:00
Mathieu Desnoyers
fb32e03fdc Create arch/Kconfig
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>
2008-02-03 08:58:07 +01:00