1. 22 12月, 2011 1 次提交
    • S
      x86: Add counter when debug stack is used with interrupts enabled · 42181186
      Steven Rostedt 提交于
      Mathieu Desnoyers pointed out a case that can cause issues with
      NMIs running on the debug stack:
      
        int3 -> interrupt -> NMI -> int3
      
      Because the interrupt changes the stack, the NMI will not see that
      it preempted the debug stack. Looking deeper at this case,
      interrupts only happen when the int3 is from userspace or in
      an a location in the exception table (fixup).
      
        userspace -> int3 -> interurpt -> NMI -> int3
      
      All other int3s that happen in the kernel should be processed
      without ever enabling interrupts, as the do_trap() call will
      panic the kernel if it is called to process any other location
      within the kernel.
      
      Adding a counter around the sections that enable interrupts while
      using the debug stack allows the NMI to also check that case.
      If the NMI sees that it either interrupted a task using the debug
      stack or the debug counter is non-zero, then it will have to
      change the IDT table to make the int3 not change stacks (which will
      corrupt the stack if it does).
      
      Note, I had to move the debug_usage functions out of processor.h
      and into debugreg.h because of the static inlined functions to
      inc and dec the debug_usage counter. __get_cpu_var() requires
      smp.h which includes processor.h, and would fail to build.
      
      Link: http://lkml.kernel.org/r/1323976535.23971.112.camel@gandalf.stny.rr.comReported-by: NMathieu Desnoyers <mathieu.desnoyers@efficios.com>
      Cc: Linus Torvalds <torvalds@linux-foundation.org>
      Cc: Peter Zijlstra <peterz@infradead.org>
      Cc: H. Peter Anvin <hpa@linux.intel.com>
      Cc: Thomas Gleixner <tglx@linutronix.de>
      Cc: Paul Turner <pjt@google.com>
      Cc: Frederic Weisbecker <fweisbec@gmail.com>
      Signed-off-by: NSteven Rostedt <rostedt@goodmis.org>
      42181186
  2. 30 12月, 2010 1 次提交
  3. 29 1月, 2010 1 次提交
  4. 25 11月, 2009 1 次提交
    • T
      x86: Rename global percpu symbol dr7 to cpu_dr7 · 28b4e0d8
      Tejun Heo 提交于
      Percpu symbols now occupy the same namespace as other global
      symbols and as such short global symbols without subsystem
      prefix tend to collide with local variables.  dr7 percpu
      variable used by x86 was hit by this. Rename it to cpu_dr7.
      
      The rename also makes it more consistent with its fellow
      cpu_debugreg percpu variable.
      Signed-off-by: NTejun Heo <tj@kernel.org>
      Cc: Frederic Weisbecker <fweisbec@gmail.com>
      Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
      Cc: Rusty Russell <rusty@rustcorp.com.au>
      Cc: Christoph Lameter <cl@linux-foundation.org>
      Cc: Linus Torvalds <torvalds@linux-foundation.org>,
      Cc: Andrew Morton <akpm@linux-foundation.org>
      LKML-Reference: <20091125115856.GA17856@elte.hu>
      Signed-off-by: NIngo Molnar <mingo@elte.hu>
      Reported-by: NStephen Rothwell <sfr@canb.auug.org.au>
      28b4e0d8
  5. 14 11月, 2009 1 次提交
    • I
      hw-breakpoints, x86: Fix modular KVM build · 68efa37d
      Ingo Molnar 提交于
      This build error:
      
      arch/x86/kvm/x86.c:3655: error: implicit declaration of function 'hw_breakpoint_restore'
      
      Happens because in the CONFIG_KVM=m case there's no 'CONFIG_KVM' define
      in the kernel - it's CONFIG_KVM_MODULE in that case.
      
      Make the prototype available unconditionally.
      
      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: NIngo Molnar <mingo@elte.hu>
      68efa37d
  6. 10 11月, 2009 2 次提交
  7. 08 11月, 2009 1 次提交
    • F
      hw-breakpoints: Rewrite the hw-breakpoints layer on top of perf events · 24f1e32c
      Frederic Weisbecker 提交于
      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: NFrederic 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
  8. 03 6月, 2009 1 次提交
  9. 23 10月, 2008 2 次提交
  10. 23 7月, 2008 1 次提交
    • V
      x86: consolidate header guards · 77ef50a5
      Vegard Nossum 提交于
      This patch is the result of an automatic script that consolidates the
      format of all the headers in include/asm-x86/.
      
      The format:
      
      1. No leading underscore. Names with leading underscores are reserved.
      2. Pathname components are separated by two underscores. So we can
         distinguish between mm_types.h and mm/types.h.
      3. Everything except letters and numbers are turned into single
         underscores.
      Signed-off-by: NVegard Nossum <vegard.nossum@gmail.com>
      77ef50a5
  11. 18 10月, 2007 1 次提交
  12. 11 10月, 2007 1 次提交