1. 19 Nov, 2012 1 commit
    • David Howells's avatar
      perf: Make perf build for x86 with UAPI disintegration applied · d2709c7c
      David Howells authored
      Make perf build for x86 once the UAPI disintegration patches for that arch
      have been applied by adding the appropriate -I flags - in the right order -
      and then converting some #includes that use ../.. notation to find main kernel
      headerfiles to use <asm/foo.h> and <linux/foo.h> instead.
      
      Note that -Iarch/foo/include/uapi is present _before_ -Iarch/foo/include.
      This makes sure we get the userspace version of the pt_regs struct.  Ideally,
      we wouldn't have the latter -I flag at all, but unfortunately we want
      asm/svm.h and asm/vmx.h in builtin-kvm.c and these aren't part of the UAPI -
      at least not for x86.  I wonder if the bits outside of the __KERNEL__ guards
      *should* be transferred there.
      
      I note also that perf seems to do its dependency handling manually by listing
      all the header files it might want to use in LIB_H in the Makefile.  Can this
      be changed to use -MD?
      
      Note that to do make this work, we need to export and UAPI disintegrate
      linux/hw_breakpoint.h, which I think should've been exported previously so that
      perf can access the bits.  We have to do this in the same patch to maintain
      bisectability.
      Signed-off-by: default avatarDavid Howells <dhowells@redhat.com>
      d2709c7c
  2. 01 Jul, 2011 1 commit
  3. 12 Nov, 2010 1 commit
    • Jason Wessel's avatar
      perf,hw_breakpoint: Initialize hardware api earlier · 3c502e7a
      Jason Wessel authored
      When using early debugging, the kernel does not initialize the
      hw_breakpoint API early enough and causes the late initialization of
      the kernel debugger to fail. The boot arguments are:
      
          earlyprintk=vga ekgdboc=kbd kgdbwait
      
      Then simply type "go" at the kdb prompt and boot. The kernel will
      later emit the message:
      
          kgdb: Could not allocate hwbreakpoints
      
      And at that point the kernel debugger will cease to work correctly.
      
      The solution is to initialize the hw_breakpoint at the same time that
      all the other perf call backs are initialized instead of using a
      core_initcall() initialization which happens well after the kernel
      debugger can make use of hardware breakpoints.
      Signed-off-by: default avatarJason Wessel <jason.wessel@windriver.com>
      CC: Frederic Weisbecker <fweisbec@gmail.com>
      CC: Ingo Molnar <mingo@elte.hu>
      CC: Peter Zijlstra <a.p.zijlstra@chello.nl>
      LKML-Reference: <4CD3396D.1090308@windriver.com>
      Signed-off-by: default avatarFrederic Weisbecker <fweisbec@gmail.com>
      3c502e7a
  4. 30 Apr, 2010 3 commits
    • Frederic Weisbecker's avatar
      hw-breakpoints: Get the number of available registers on boot dynamically · feef47d0
      Frederic Weisbecker authored
      The breakpoint generic layer assumes that archs always know in advance
      the static number of address registers available to host breakpoints
      through the HBP_NUM macro.
      
      However this is not true for every archs. For example Arm needs to get
      this information dynamically to handle the compatiblity between
      different versions.
      
      To solve this, this patch proposes to drop the static HBP_NUM macro
      and let the arch provide the number of available slots through a
      new hw_breakpoint_slots() function. For archs that have
      CONFIG_HAVE_MIXED_BREAKPOINTS_REGS selected, it will be called once
      as the number of registers fits for instruction and data breakpoints
      together.
      For the others it will be called first to get the number of
      instruction breakpoint registers and another time to get the
      data breakpoint registers, the targeted type is given as a
      parameter of hw_breakpoint_slots().
      Reported-by: default avatarWill Deacon <will.deacon@arm.com>
      Signed-off-by: default avatarFrederic Weisbecker <fweisbec@gmail.com>
      Acked-by: default avatarPaul Mundt <lethal@linux-sh.org>
      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: Jason Wessel <jason.wessel@windriver.com>
      Cc: Ingo Molnar <mingo@elte.hu>
      feef47d0
    • Frederic Weisbecker's avatar
      hw-breakpoints: Separate constraint space for data and instruction breakpoints · 0102752e
      Frederic Weisbecker authored
      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: default avatarFrederic Weisbecker <fweisbec@gmail.com>
      Acked-by: default avatarPaul 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>
      0102752e
    • Frederic Weisbecker's avatar
      hw-breakpoints: Tag ptrace breakpoint as exclude_kernel · 73266fc1
      Frederic Weisbecker authored
      Tag ptrace breakpoints with the exclude_kernel attribute set. This
      will make it easier to set generic policies on breakpoints, when it
      comes to ensure nobody unpriviliged try to breakpoint on the kernel.
      Signed-off-by: default avatarFrederic Weisbecker <fweisbec@gmail.com>
      Acked-by: default avatarPaul 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>
      73266fc1
  5. 27 Feb, 2010 1 commit
    • Tejun Heo's avatar
      percpu: Add __percpu sparse annotations to hw_breakpoint · 44ee6358
      Tejun Heo authored
      Add __percpu sparse annotations to hw_breakpoint.
      
      These annotations are to make sparse consider percpu variables to be
      in a different address space and warn if accessed without going
      through percpu accessors.  This patch doesn't affect normal builds.
      
      In kernel/hw_breakpoint.c, per_cpu(nr_task_bp_pinned, cpu)'s will
      trigger spurious noderef related warnings from sparse.  Changing it to
      &per_cpu(nr_task_bp_pinned[0], cpu) will work around the problem but
      deemed to ugly by the maintainer.  Leave it alone until better
      solution can be found.
      Signed-off-by: default avatarTejun Heo <tj@kernel.org>
      Cc: Stephen Rothwell <sfr@canb.auug.org.au>
      Cc: K.Prasad <prasad@linux.vnet.ibm.com>
      LKML-Reference: <4B7B4B7A.9050902@kernel.org>
      Signed-off-by: default avatarFrederic Weisbecker <fweisbec@gmail.com>
      44ee6358
  6. 03 Feb, 2010 1 commit
  7. 30 Jan, 2010 1 commit
    • Jason Wessel's avatar
      perf, hw_breakpoint, kgdb: Do not take mutex for kernel debugger · 5352ae63
      Jason Wessel authored
      This patch fixes the regression in functionality where the
      kernel debugger and the perf API do not nicely share hw
      breakpoint reservations.
      
      The kernel debugger cannot use any mutex_lock() calls because it
      can start the kernel running from an invalid context.
      
      A mutex free version of the reservation API needed to get
      created for the kernel debugger to safely update hw breakpoint
      reservations.
      
      The possibility for a breakpoint reservation to be concurrently
      processed at the time that kgdb interrupts the system is
      improbable. Should this corner case occur the end user is
      warned, and the kernel debugger will prohibit updating the
      hardware breakpoint reservations.
      
      Any time the kernel debugger reserves a hardware breakpoint it
      will be a system wide reservation.
      Signed-off-by: default avatarJason Wessel <jason.wessel@windriver.com>
      Acked-by: default avatarFrederic Weisbecker <fweisbec@gmail.com>
      Cc: kgdb-bugreport@lists.sourceforge.net
      Cc: K.Prasad <prasad@linux.vnet.ibm.com>
      Cc: Peter Zijlstra <peterz@infradead.org>
      Cc: Alan Stern <stern@rowland.harvard.edu>
      Cc: torvalds@linux-foundation.org
      LKML-Reference: <1264719883-7285-3-git-send-email-jason.wessel@windriver.com>
      Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
      5352ae63
  8. 14 Dec, 2009 1 commit
  9. 11 Dec, 2009 1 commit
  10. 09 Dec, 2009 1 commit
    • Frederic Weisbecker's avatar
      hw-breakpoints: Modify breakpoints without unregistering them · 44234adc
      Frederic Weisbecker authored
      Currently, when ptrace needs to modify a breakpoint, like disabling
      it, changing its address, type or len, it calls
      modify_user_hw_breakpoint(). This latter will perform the heavy and
      racy task of unregistering the old breakpoint and registering a new
      one.
      
      This is racy as someone else might steal the reserved breakpoint
      slot under us, which is undesired as the breakpoint is only
      supposed to be modified, sometimes in the middle of a debugging
      workflow. We don't want our slot to be stolen in the middle.
      
      So instead of unregistering/registering the breakpoint, just
      disable it while we modify its breakpoint fields and re-enable it
      after if necessary.
      Signed-off-by: default avatarFrederic Weisbecker <fweisbec@gmail.com>
      Cc: Peter Zijlstra <peterz@infradead.org>
      Cc: Prasad <prasad@linux.vnet.ibm.com>
      LKML-Reference: <1260347148-5519-1-git-send-regression-fweisbec@gmail.com>
      Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
      44234adc
  11. 06 Dec, 2009 3 commits
  12. 26 Nov, 2009 2 commits
  13. 23 Nov, 2009 2 commits
  14. 22 Nov, 2009 1 commit
  15. 13 Nov, 2009 2 commits
    • Ingo Molnar's avatar
      hw-breakpoints: Fix build on !perf architectures · 688bcaff
      Ingo Molnar authored
      the arch/alpha build fails with:
      
       In file included from tip/kernel/exit.c:52:
       tip/include/linux/hw_breakpoint.h: In function 'hw_breakpoint_addr':
       tip/include/linux/hw_breakpoint.h:21: error: 'struct perf_event' has no member named 'attr'
       [...]
      
      Move these helper inlines inside the CONFIG_HAVE_HW_BREAKPOINT ifdef.
      
      Cc: Frederic Weisbecker <fweisbec@gmail.com>
      Cc: Prasad <prasad@linux.vnet.ibm.com>
      LKML-Reference: <1258114575-32655-1-git-send-email-fweisbec@gmail.com>
      Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
      688bcaff
    • Frederic Weisbecker's avatar
      hw-breakpoints: Provide an off-case for counter_arch_bp() · 687b16fb
      Frederic Weisbecker authored
      If an arch doesn't support the hw breakpoints, counter_arch_bp()
      has no off case to cover the missing breakpoint info structure
      from the perf event. The result is a build error in non-x86
      configs.
      Reported-by: default avatarIngo Molnar <mingo@elte.hu>
      Signed-off-by: default avatarFrederic Weisbecker <fweisbec@gmail.com>
      Cc: Prasad <prasad@linux.vnet.ibm.com>
      LKML-Reference: <1258114575-32655-1-git-send-email-fweisbec@gmail.com>
      Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
      Cc: Prasad <prasad@linux.vnet.ibm.com>
      687b16fb
  16. 08 Nov, 2009 1 commit
    • Frederic Weisbecker's avatar
      hw-breakpoints: Rewrite the hw-breakpoints layer on top of perf events · 24f1e32c
      Frederic Weisbecker authored
      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: default avatarFrederic 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>
      24f1e32c
  17. 05 Nov, 2009 1 commit
  18. 02 Jun, 2009 1 commit