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* perf/x86/amd: AMD support for bp_len > HW_BREAKPOINT_LEN_8Jacob Shin2014-12-031-0/+5
| | | | | | | | | | | | | | | | | | | | Implement hardware breakpoint address mask for AMD Family 16h and above processors. CPUID feature bit indicates hardware support for DRn_ADDR_MASK MSRs. These masks further qualify DRn/DR7 hardware breakpoint addresses to allow matching of larger addresses ranges. Valuable advice and pseudo code from Oleg Nesterov <oleg@redhat.com> Signed-off-by: Jacob Shin <jacob.w.shin@gmail.com> Signed-off-by: Suravee Suthikulpanit <suravee.suthikulpanit@amd.com> Acked-by: Jiri Olsa <jolsa@kernel.org> Reviewed-by: Oleg Nesterov <oleg@redhat.com> Cc: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Cc: Ingo Molnar <mingo@kernel.org> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: xiakaixu <xiakaixu@huawei.com> Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
* x86: Replace __get_cpu_var usesChristoph Lameter2014-08-261-2/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | __get_cpu_var() is used for multiple purposes in the kernel source. One of them is address calculation via the form &__get_cpu_var(x). This calculates the address for the instance of the percpu variable of the current processor based on an offset. Other use cases are for storing and retrieving data from the current processors percpu area. __get_cpu_var() can be used as an lvalue when writing data or on the right side of an assignment. __get_cpu_var() is defined as : #define __get_cpu_var(var) (*this_cpu_ptr(&(var))) __get_cpu_var() always only does an address determination. However, store and retrieve operations could use a segment prefix (or global register on other platforms) to avoid the address calculation. this_cpu_write() and this_cpu_read() can directly take an offset into a percpu area and use optimized assembly code to read and write per cpu variables. This patch converts __get_cpu_var into either an explicit address calculation using this_cpu_ptr() or into a use of this_cpu operations that use the offset. Thereby address calculations are avoided and less registers are used when code is generated. Transformations done to __get_cpu_var() 1. Determine the address of the percpu instance of the current processor. DEFINE_PER_CPU(int, y); int *x = &__get_cpu_var(y); Converts to int *x = this_cpu_ptr(&y); 2. Same as #1 but this time an array structure is involved. DEFINE_PER_CPU(int, y[20]); int *x = __get_cpu_var(y); Converts to int *x = this_cpu_ptr(y); 3. Retrieve the content of the current processors instance of a per cpu variable. DEFINE_PER_CPU(int, y); int x = __get_cpu_var(y) Converts to int x = __this_cpu_read(y); 4. Retrieve the content of a percpu struct DEFINE_PER_CPU(struct mystruct, y); struct mystruct x = __get_cpu_var(y); Converts to memcpy(&x, this_cpu_ptr(&y), sizeof(x)); 5. Assignment to a per cpu variable DEFINE_PER_CPU(int, y) __get_cpu_var(y) = x; Converts to __this_cpu_write(y, x); 6. Increment/Decrement etc of a per cpu variable DEFINE_PER_CPU(int, y); __get_cpu_var(y)++ Converts to __this_cpu_inc(y) Cc: Thomas Gleixner <tglx@linutronix.de> Cc: x86@kernel.org Acked-by: H. Peter Anvin <hpa@linux.intel.com> Acked-by: Ingo Molnar <mingo@kernel.org> Signed-off-by: Christoph Lameter <cl@linux.com> Signed-off-by: Tejun Heo <tj@kernel.org>
* UAPI: (Scripted) Disintegrate arch/x86/include/asmDavid Howells2012-12-141-78/+1
| | | | | | | | | Signed-off-by: David Howells <dhowells@redhat.com> Acked-by: Arnd Bergmann <arnd@arndb.de> Acked-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: Michael Kerrisk <mtk.manpages@gmail.com> Acked-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Acked-by: Dave Jones <davej@redhat.com>
* x86: relocate get/set debugreg fcns to include/asm/debugreg.Paul Gortmaker2012-02-281-0/+67
| | | | | | | | | | | | | | | | Since we already have a debugreg.h header file, move the assoc. get/set functions to it. In addition to it being the logical home for them, it has a secondary advantage. The functions that are moved use BUG(). So we really need to have linux/bug.h in scope. But asm/processor.h is used about 600 times, vs. only about 15 for debugreg.h -- so adding bug.h to the latter reduces the amount of time we'll be processing it during a compile. Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com> Acked-by: Ingo Molnar <mingo@elte.hu> CC: Thomas Gleixner <tglx@linutronix.de> CC: "H. Peter Anvin" <hpa@zytor.com>
* x86: Add counter when debug stack is used with interrupts enabledSteven Rostedt2011-12-211-0/+22
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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.com Reported-by: Mathieu 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: Steven Rostedt <rostedt@goodmis.org>
* x86: Use this_cpu_ops to optimize codeTejun Heo2010-12-301-1/+1
| | | | | | | | | | | | | Go through x86 code and replace __get_cpu_var and get_cpu_var instances that refer to a scalar and are not used for address determinations. Cc: Yinghai Lu <yinghai@kernel.org> Cc: Ingo Molnar <mingo@elte.hu> Acked-by: Tejun Heo <tj@kernel.org> Acked-by: "H. Peter Anvin" <hpa@zytor.com> Signed-off-by: Christoph Lameter <cl@linux.com> Signed-off-by: Tejun Heo <tj@kernel.org>
* x86/debug: Clear reserved bits of DR6 in do_debug()K.Prasad2010-01-291-0/+3
| | | | | | | | | | | | | | | Clear the reserved bits from the stored copy of debug status register (DR6). This will help easy bitwise operations such as quick testing of a debug event origin. Signed-off-by: K.Prasad <prasad@linux.vnet.ibm.com> Cc: Roland McGrath <roland@redhat.com> Cc: Jan Kiszka <jan.kiszka@siemens.com> Cc: Alan Stern <stern@rowland.harvard.edu> Cc: Ingo Molnar <mingo@elte.hu> LKML-Reference: <20100128111401.GB13935@in.ibm.com> Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
* x86: Rename global percpu symbol dr7 to cpu_dr7Tejun Heo2009-11-251-2/+2
| | | | | | | | | | | | | | | | | | | | | 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: Tejun 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: Ingo Molnar <mingo@elte.hu> Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
* hw-breakpoints, x86: Fix modular KVM buildIngo Molnar2009-11-141-2/+0
| | | | | | | | | | | | | | | | 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: Ingo Molnar <mingo@elte.hu>
* hw-breakpoints: Wrap in the KVM breakpoint active state checkFrederic Weisbecker2009-11-101-0/+5
| | | | | | | | | | | | | Wrap in the cpu dr7 check that tells if we have active breakpoints that need to be restored in the cpu. This wrapper makes the check more self-explainable and also reusable for any further other uses. Reported-by: Jan Kiszka <jan.kiszka@web.de> Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Avi Kivity <avi@redhat.com> Cc: "K. Prasad" <prasad@linux.vnet.ibm.com>
* hw-breakpoints: Fix broken a.out format dumpFrederic Weisbecker2009-11-101-0/+2
| | | | | | | | | | | | Fix the broken a.out format dump. For now we only dump the ptrace breakpoints. TODO: Dump every perf breakpoints for the current thread, not only ptrace based ones. Reported-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: "K. Prasad" <prasad@linux.vnet.ibm.com>
* hw-breakpoints: Rewrite the hw-breakpoints layer on top of perf eventsFrederic Weisbecker2009-11-081-6/+5
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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>
* hw-breakpoints: prepare the code for Hardware Breakpoint interfacesK.Prasad2009-06-021-0/+29
| | | | | | | | | | | | | | | | | | | | | | The generic hardware breakpoint interface provides an abstraction of hardware breakpoints in front of specific arch implementations for both kernel and user side breakpoints. This includes execution breakpoints and read/write breakpoints, also known as "watchpoints". This patch introduces header files containing constants, structure definitions and declaration of functions used by the hardware breakpoint core and x86 specific code. It also introduces an array based storage for the debug-register values in 'struct thread_struct', while modifying all users of debugreg<n> member in the structure. [ Impact: add headers for new hardware breakpoint interface ] 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>
* x86: Fix ASM_X86__ header guardsH. Peter Anvin2008-10-221-3/+3
| | | | | | | | | Change header guards named "ASM_X86__*" to "_ASM_X86_*" since: a. the double underscore is ugly and pointless. b. no leading underscore violates namespace constraints. Signed-off-by: H. Peter Anvin <hpa@zytor.com>
* x86, um: ... and asm-x86 moveAl Viro2008-10-221-0/+70
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: H. Peter Anvin <hpa@zytor.com>
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