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* kgdb,x86: fix warning about unused variableJason Wessel2012-10-121-0/+2
| | | | | | | | | | | | | | When compiling without CONFIG_DEBUG_RODATA the following compiler warning is generated: arch/x86/kernel/kgdb.c: In function 'kgdb_arch_set_breakpoint': arch/x86/kernel/kgdb.c:749: warning: unused variable 'opc' The variable instantiation needs to be inside the #ifdef to make the warning go away. Reported-by: Thiago Rafael Becker <trbecker@trbecker.org> Signed-off-by: Jason Wessel <jason.wessel@windriver.com>
* x86: Fix kernel-doc warningsWanpeng Li2012-06-181-4/+4
| | | | | | | | | | Signed-off-by: Wanpeng Li <liwp@linux.vnet.ibm.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Jason Wessel <jason.wessel@windriver.com> Cc: Jan Kiszka <jan.kiszka@siemens.com> Cc: Gavin Shan <shangw@linux.vnet.ibm.com> Cc: Wanpeng Li <liwp.linux@gmail.com> Signed-off-by: Ingo Molnar <mingo@kernel.org>
* Merge tag 'for_linus-3.4-rc2' of ↵Linus Torvalds2012-04-041-0/+60
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/jwessel/kgdb Pull KGDB/KDB regression fixes from Jason Wessel: - Fix a Smatch warning that appeared in the 3.4 merge window - Fix kgdb test suite with SMP for all archs without HW single stepping - Fix kgdb sw breakpoints with CONFIG_DEBUG_RODATA=y limitations on x86 - Fix oops on kgdb test suite with CONFIG_DEBUG_RODATA - Fix kgdb test suite with SMP for all archs with HW single stepping * tag 'for_linus-3.4-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/jwessel/kgdb: x86,kgdb: Fix DEBUG_RODATA limitation using text_poke() kgdb,debug_core: pass the breakpoint struct instead of address and memory kgdbts: (2 of 2) fix single step awareness to work correctly with SMP kgdbts: (1 of 2) fix single step awareness to work correctly with SMP kgdbts: Fix kernel oops with CONFIG_DEBUG_RODATA kdb: Fix smatch warning on dbg_io_ops->is_console
| * x86,kgdb: Fix DEBUG_RODATA limitation using text_poke()Jason Wessel2012-03-291-0/+60
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | There has long been a limitation using software breakpoints with a kernel compiled with CONFIG_DEBUG_RODATA going back to 2.6.26. For this particular patch, it will apply cleanly and has been tested all the way back to 2.6.36. The kprobes code uses the text_poke() function which accommodates writing a breakpoint into a read-only page. The x86 kgdb code can solve the problem similarly by overriding the default breakpoint set/remove routines and using text_poke() directly. The x86 kgdb code will first attempt to use the traditional probe_kernel_write(), and next try using a the text_poke() function. The break point install method is tracked such that the correct break point removal routine will get called later on. Cc: x86@kernel.org Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Ingo Molnar <mingo@redhat.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: stable@vger.kernel.org # >= 2.6.36 Inspried-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> Signed-off-by: Jason Wessel <jason.wessel@windriver.com>
* | Merge tag 'split-asm_system_h-for-linus-20120328' of ↵Linus Torvalds2012-03-281-1/+0
|\ \ | |/ |/| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-asm_system Pull "Disintegrate and delete asm/system.h" from David Howells: "Here are a bunch of patches to disintegrate asm/system.h into a set of separate bits to relieve the problem of circular inclusion dependencies. I've built all the working defconfigs from all the arches that I can and made sure that they don't break. The reason for these patches is that I recently encountered a circular dependency problem that came about when I produced some patches to optimise get_order() by rewriting it to use ilog2(). This uses bitops - and on the SH arch asm/bitops.h drags in asm-generic/get_order.h by a circuituous route involving asm/system.h. The main difficulty seems to be asm/system.h. It holds a number of low level bits with no/few dependencies that are commonly used (eg. memory barriers) and a number of bits with more dependencies that aren't used in many places (eg. switch_to()). These patches break asm/system.h up into the following core pieces: (1) asm/barrier.h Move memory barriers here. This already done for MIPS and Alpha. (2) asm/switch_to.h Move switch_to() and related stuff here. (3) asm/exec.h Move arch_align_stack() here. Other process execution related bits could perhaps go here from asm/processor.h. (4) asm/cmpxchg.h Move xchg() and cmpxchg() here as they're full word atomic ops and frequently used by atomic_xchg() and atomic_cmpxchg(). (5) asm/bug.h Move die() and related bits. (6) asm/auxvec.h Move AT_VECTOR_SIZE_ARCH here. Other arch headers are created as needed on a per-arch basis." Fixed up some conflicts from other header file cleanups and moving code around that has happened in the meantime, so David's testing is somewhat weakened by that. We'll find out anything that got broken and fix it.. * tag 'split-asm_system_h-for-linus-20120328' of git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-asm_system: (38 commits) Delete all instances of asm/system.h Remove all #inclusions of asm/system.h Add #includes needed to permit the removal of asm/system.h Move all declarations of free_initmem() to linux/mm.h Disintegrate asm/system.h for OpenRISC Split arch_align_stack() out from asm-generic/system.h Split the switch_to() wrapper out of asm-generic/system.h Move the asm-generic/system.h xchg() implementation to asm-generic/cmpxchg.h Create asm-generic/barrier.h Make asm-generic/cmpxchg.h #include asm-generic/cmpxchg-local.h Disintegrate asm/system.h for Xtensa Disintegrate asm/system.h for Unicore32 [based on ver #3, changed by gxt] Disintegrate asm/system.h for Tile Disintegrate asm/system.h for Sparc Disintegrate asm/system.h for SH Disintegrate asm/system.h for Score Disintegrate asm/system.h for S390 Disintegrate asm/system.h for PowerPC Disintegrate asm/system.h for PA-RISC Disintegrate asm/system.h for MN10300 ...
| * Disintegrate asm/system.h for X86David Howells2012-03-281-1/+0
| | | | | | | | | | | | | | | | Disintegrate asm/system.h for X86. Signed-off-by: David Howells <dhowells@redhat.com> Acked-by: H. Peter Anvin <hpa@zytor.com> cc: x86@kernel.org
* | kgdb: x86: Return all segment registers also in 64-bit modeJan Kiszka2012-03-221-2/+4
|/ | | | | | | | | | Even if the content is always 0, gdb expects us to return also ds, es, fs, and gs while in x86-64 mode. Do this to avoid ugly errors on "info registers". [jason.wessel@windriver.com: adjust NUMREGBYTES for two new regs] Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com> Signed-off-by: Jason Wessel <jason.wessel@windriver.com>
* x86, nmi: Wire up NMI handlers to new routinesDon Zickus2011-10-101-15/+45
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Just convert all the files that have an nmi handler to the new routines. Most of it is straight forward conversion. A couple of places needed some tweaking like kgdb which separates the debug notifier from the nmi handler and mce removes a call to notify_die. [Thanks to Ying for finding out the history behind that mce call https://lkml.org/lkml/2010/5/27/114 And Boris responding that he would like to remove that call because of it https://lkml.org/lkml/2011/9/21/163] The things that get converted are the registeration/unregistration routines and the nmi handler itself has its args changed along with code removal to check which list it is on (most are on one NMI list except for kgdb which has both an NMI routine and an NMI Unknown routine). Signed-off-by: Don Zickus <dzickus@redhat.com> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Acked-by: Corey Minyard <minyard@acm.org> Cc: Jason Wessel <jason.wessel@windriver.com> Cc: Andi Kleen <ak@linux.intel.com> Cc: Robert Richter <robert.richter@amd.com> Cc: Huang Ying <ying.huang@intel.com> Cc: Corey Minyard <minyard@acm.org> Cc: Jack Steiner <steiner@sgi.com> Link: http://lkml.kernel.org/r/1317409584-23662-4-git-send-email-dzickus@redhat.com Signed-off-by: Ingo Molnar <mingo@elte.hu>
* perf: Add context field to perf_eventAvi Kivity2011-07-011-1/+1
| | | | | | | | | | | | | | | | | The perf_event overflow handler does not receive any caller-derived argument, so many callers need to resort to looking up the perf_event in their local data structure. This is ugly and doesn't scale if a single callback services many perf_events. Fix by adding a context parameter to perf_event_create_kernel_counter() (and derived hardware breakpoints APIs) and storing it in the perf_event. The field can be accessed from the callback as event->overflow_handler_context. All callers are updated. Signed-off-by: Avi Kivity <avi@redhat.com> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Link: http://lkml.kernel.org/r/1309362157-6596-2-git-send-email-avi@redhat.com Signed-off-by: Ingo Molnar <mingo@elte.hu>
* perf: Remove the nmi parameter from the swevent and overflow interfacePeter Zijlstra2011-07-011-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The nmi parameter indicated if we could do wakeups from the current context, if not, we would set some state and self-IPI and let the resulting interrupt do the wakeup. For the various event classes: - hardware: nmi=0; PMI is in fact an NMI or we run irq_work_run from the PMI-tail (ARM etc.) - tracepoint: nmi=0; since tracepoint could be from NMI context. - software: nmi=[0,1]; some, like the schedule thing cannot perform wakeups, and hence need 0. As one can see, there is very little nmi=1 usage, and the down-side of not using it is that on some platforms some software events can have a jiffy delay in wakeup (when arch_irq_work_raise isn't implemented). The up-side however is that we can remove the nmi parameter and save a bunch of conditionals in fast paths. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Michael Cree <mcree@orcon.net.nz> Cc: Will Deacon <will.deacon@arm.com> Cc: Deng-Cheng Zhu <dengcheng.zhu@gmail.com> Cc: Anton Blanchard <anton@samba.org> Cc: Eric B Munson <emunson@mgebm.net> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: Paul Mundt <lethal@linux-sh.org> Cc: David S. Miller <davem@davemloft.net> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Jason Wessel <jason.wessel@windriver.com> Cc: Don Zickus <dzickus@redhat.com> Link: http://lkml.kernel.org/n/tip-agjev8eu666tvknpb3iaj0fg@git.kernel.org Signed-off-by: Ingo Molnar <mingo@elte.hu>
* Merge branch 'for_linus' of ↵Linus Torvalds2011-03-251-2/+2
|\ | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/jwessel/linux-2.6-kgdb * 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jwessel/linux-2.6-kgdb: kdb: add usage string of 'per_cpu' command kgdb,x86_64: fix compile warning found with sparse kdb: code cleanup to use macro instead of value kgdboc,kgdbts: strlen() doesn't count the terminator
| * kgdb,x86_64: fix compile warning found with sparseJason Wessel2011-03-251-2/+2
| | | | | | | | | | | | | | | | | | Fix sparse warning: arch/x86/kernel/kgdb.c:123:9: warning: switch with no cases Reported-by: Namhyung Kim <namhyung@gmail.com> Signed-off-by: Jason Wessel <jason.wessel@windriver.com>
* | x86: Fix common misspellingsLucas De Marchi2011-03-181-1/+1
| | | | | | | | | | | | | | | | | | They were generated by 'codespell' and then manually reviewed. Signed-off-by: Lucas De Marchi <lucas.demarchi@profusion.mobi> Cc: trivial@kernel.org LKML-Reference: <1300389856-1099-3-git-send-email-lucas.demarchi@profusion.mobi> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* | x86: Remove die_nmi()Jan Beulich2011-02-181-9/+0
|/ | | | | | | | | | | With no caller left, the function and the DIE_NMIWATCHDOG enumerator can both go away. Signed-off-by: Jan Beulich <jbeulich@novell.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Don Zickus <dzickus@redhat.com> LKML-Reference: <4D5D521C0200007800032702@vpn.id2.novell.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* x86, NMI: Remove DIE_NMI_IPIDon Zickus2011-01-071-4/+0
| | | | | | | | | | | | | | | | | With priorities in place and no one really understanding the difference between DIE_NMI and DIE_NMI_IPI, just remove DIE_NMI_IPI and convert everyone to DIE_NMI. This also simplifies default_do_nmi() a little bit. Instead of calling the die_notifier in both the if and else part, just pull it out and call it before the if-statement. This has the side benefit of avoiding a call to the ioport to see if there is an external NMI sitting around until after the (more frequent) internal NMIs are dealt with. Patch-Inspired-by: Huang Ying <ying.huang@intel.com> Signed-off-by: Don Zickus <dzickus@redhat.com> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> LKML-Reference: <1294348732-15030-5-git-send-email-dzickus@redhat.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* x86, NMI: Add priorities to handlersDon Zickus2011-01-071-1/+2
| | | | | | | | | | | | | | | | | In order to consolidate the NMI die_chain events, we need to setup the priorities for the die notifiers. I started by defining a bunch of common priorities that can be used by the notifier blocks. Then I modified the notifier blocks to use the newly created priorities. Now that the priorities are straightened out, it should be easier to remove the event DIE_NMI_IPI. Signed-off-by: Don Zickus <dzickus@redhat.com> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> LKML-Reference: <1294348732-15030-4-git-send-email-dzickus@redhat.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* kgdb,x86: fix regression in detach handlingJason Wessel2010-11-171-4/+8
| | | | | | | | | | | | | | | | | | | | | | The fix from ba773f7c510c0b252145933926c636c439889207 (x86,kgdb: Fix hw breakpoint regression) was not entirely complete. The kgdb_remove_all_hw_break() function also needs to call the hw_break_release_slot() or else a breakpoint can get activated again after the debugger has detached. The kgdb test suite exposes the behavior in the form of either a hang or repetitive failure. The kernel config that exposes the problem contains all of the following: CONFIG_DEBUG_RODATA=y CONFIG_KGDB_TESTS=y CONFIG_KGDB_TESTS_ON_BOOT=y CONFIG_KGDB_TESTS_BOOT_STRING="V1F100" Reported-by: Frederic Weisbecker <fweisbec@gmail.com> Signed-off-by: Jason Wessel <jason.wessel@windriver.com> Tested-by: Frederic Weisbecker <fweisbec@gmail.com>
* debug_core,x86,blackfin: Clean up hw debug disable APIDongdong Deng2010-10-291-1/+2
| | | | | | | | | | | | | The kgdb_disable_hw_debug() was an architecture specific function for disabling all hardware breakpoints on a per cpu basis when entering the debug core. This patch will remove the weak function kdbg_disable_hw_debug() and change it into a call back which lives with the rest of hw breakpoint call backs in struct kgdb_arch. Signed-off-by: Dongdong Deng <dongdong.deng@windriver.com> Signed-off-by: Jason Wessel <jason.wessel@windriver.com>
* x86,kgdb: remove unnecessary call to kgdb_correct_hw_break()Dongdong Deng2010-10-221-2/+0
| | | | | | | | | | | | | The kernel debug_core invokes hw breakpoint install and removal via call backs. The architecture specific kgdb stubs only need to implement the call backs and not actually call the functions. Signed-off-by: Dongdong Deng <dongdong.deng@windriver.com> Signed-off-by: Jason Wessel <jason.wessel@windriver.com> CC: x86@kernel.org CC: Thomas Gleixner <tglx@linutronix.de> CC: Ingo Molnar <mingo@redhat.com> CC: H. Peter Anvin <hpa@zytor.com>
* kdb,kgdb: fix sparse fixupsJason Wessel2010-10-221-1/+1
| | | | | | | | | | | | | | | | | Fix the following sparse warnings: kdb_main.c:328:5: warning: symbol 'kdbgetu64arg' was not declared. Should it be static? kgdboc.c:246:12: warning: symbol 'kgdboc_early_init' was not declared. Should it be static? kgdb.c:652:26: warning: incorrect type in argument 1 (different address spaces) kgdb.c:652:26: expected void const *ptr kgdb.c:652:26: got struct perf_event *[noderef] <asn:3>*pev The one in kgdb.c required the (void * __force) because of the return code from register_wide_hw_breakpoint looking like: return (void __percpu __force *)ERR_PTR(err); Signed-off-by: Jason Wessel <jason.wessel@windriver.com>
* x86,kgdb: fix debugger hw breakpoint test regression in 2.6.35Jason Wessel2010-10-221-1/+6
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | HW breakpoints events stopped working correctly with kgdb as a result of commit: 018cbffe6819f6f8db20a0a3acd9bab9bfd667e4 (Merge commit 'v2.6.33' into perf/core), later commit: ba773f7c510c0b252145933926c636c439889207 (x86,kgdb: Fix hw breakpoint regression) allowed breakpoints to propagate to the debugger core but did not completely address the original regression in functionality found in 2.6.35. When the DR_STEP flag is set in dr6 along with any of the DR_TRAP bits, the kgdb exception handler will enter once from the hw_breakpoint API call back and again from the die notifier for do_debug(), which causes the debugger to stop twice and also for the kgdb regression tests to fail running under kvm with: echo V2I1 > /sys/module/kgdbts/parameters/kgdbts To address the problem, the kgdb overflow handler needs to implement the same logic as the ptrace overflow handler call back with respect to updating the virtual copy of dr6. This will allow the kgdb do_debug() die notifier to properly handle the exception and the attached debugger, or kgdb test suite, will only receive a single notification. Signed-off-by: Jason Wessel <jason.wessel@windriver.com> CC: Frederic Weisbecker <fweisbec@gmail.com> CC: x86@kernel.org
* kgdb: add missing __percpu markup in arch/x86/kernel/kgdb.cNamhyung Kim2010-08-161-1/+1
| | | | | | | | breakinfo->pev is a pointer to percpu pointer but was missing __percpu markup. Add it. Signed-off-by: Namhyung Kim <namhyung@gmail.com> Signed-off-by: Jason Wessel <jason.wessel@windriver.com>
* kgdb,x86: use macro HBP_NUM to replace magic number 4Dongdong Deng2010-08-051-9/+9
| | | | | | | Use the macros provided by the HW breakpoint API. Signed-off-by: Dongdong Deng <dongdong.deng@windriver.com> Signed-off-by: Jason Wessel <jason.wessel@windriver.com>
* KGDB: Remove set but unused newPCAndi Kleen2010-08-051-3/+0
| | | | | | | Found by gcc 4.6's new warnings Signed-off-by: Andi Kleen <ak@linux.intel.com> Signed-off-by: Jason Wessel <jason.wessel@windriver.com>
* kgdb,x86: Individual register get/set for x86Jason Wessel2010-08-051-85/+83
| | | | | | | | | | Implement the ability to individually get and set registers for kdb and kgdb for x86. Signed-off-by: Jason Wessel <jason.wessel@windriver.com> Acked-by: H. Peter Anvin <hpa@zytor.com> CC: Ingo Molnar <mingo@redhat.com> CC: x86@kernel.org
* x86,kgdb: Fix hw breakpoint regressionJason Wessel2010-07-281-2/+7
| | | | | | | | | | | | | | | | | | | | | HW breakpoints events stopped working correctly with kgdb as a result of commit: 018cbffe6819f6f8db20a0a3acd9bab9bfd667e4 (Merge commit 'v2.6.33' into perf/core). The regression occurred because the behavior changed for setting NOTIFY_STOP as the return value to the die notifier if the breakpoint was known to the HW breakpoint API. Because kgdb is using the HW breakpoint API to register HW breakpoints slots, it must also now implement the overflow_handler call back else kgdb does not get to see the events from the die notifier. The kgdb_ll_trap function will be changed to be general purpose code which can allow an easy way to implement the hw_breakpoint API overflow call back. Signed-off-by: Jason Wessel <jason.wessel@windriver.com> Acked-by: Dongdong Deng <dongdong.deng@windriver.com> Acked-by: Frederic Weisbecker <fweisbec@gmail.com>
* x86,kgdb: Implement early hardware breakpoint debuggingJason Wessel2010-05-201-2/+28
| | | | | | | | | | | | | | | It is not possible to use the hw_breakpoint.c API prior to mm_init(), but it is possible to use hardware breakpoints with the kernel debugger. Prior to smp_init() it is possible to simply write to the dr registers of the boot cpu directly. This can be used up until the kgdb_arch_late() is invoked, at which point the standard hw_breakpoint.c API will get used. CC: Frederic Weisbecker <fweisbec@gmail.com> CC: Ingo Molnar <mingo@elte.hu> Signed-off-by: Jason Wessel <jason.wessel@windriver.com>
* x86, kgdb, init: Add early and late debug statesJason Wessel2010-05-201-7/+10
| | | | | | | | | | | | | | | | | | The kernel debugger can operate well before mm_init(), but the x86 hardware breakpoint code which uses the perf api requires that the kernel allocators are initialized. This means the kernel debug core needs to provide an optional arch specific call back to allow the initialization functions to run after the kernel has been further initialized. The kdb shell already had a similar restriction with an early initialization and late initialization. The kdb_init() was moved into the debug core's version of the late init which is called dbg_late_init(); CC: kgdb-bugreport@lists.sourceforge.net Signed-off-by: Jason Wessel <jason.wessel@windriver.com>
* x86,kgdb: Add low level debug hookJason Wessel2010-05-201-1/+21
| | | | | | | | | | | | | | | | | The only way the debugger can handle a trap in inside rcu_lock, notify_die, or atomic_notifier_call_chain without a triple fault is to have a low level "first opportunity handler" in the int3 exception handler. Generally this will be something the vast majority of folks will not need, but for those who need it, it is added as a kernel .config option called KGDB_LOW_LEVEL_TRAP. CC: Ingo Molnar <mingo@elte.hu> CC: Thomas Gleixner <tglx@linutronix.de> CC: H. Peter Anvin <hpa@zytor.com> CC: x86@kernel.org Signed-off-by: Jason Wessel <jason.wessel@windriver.com>
* kgdb: remove post_primary_code referencesJason Wessel2010-05-201-29/+0
| | | | | | | | | | | Remove all the references to the kgdb_post_primary_code. This function serves no useful purpose because you can obtain the same information from the "struct kgdb_state *ks" from with in the debugger, if for some reason you want the data. Also remove the unintentional duplicate assignment for ks->ex_vector. Signed-off-by: Jason Wessel <jason.wessel@windriver.com>
* kgdb: core changes to support kdbJason Wessel2010-05-201-0/+5
| | | | | | | | | | | | | | | | | | | | | | | | | | These are the minimum changes to the kgdb core in order to enable an API to connect a new front end (kdb) to the debug core. This patch introduces the dbg_kdb_mode variable controls where the user level I/O is routed. It will be routed to the gdbstub (kgdb) or to the kdb front end which is a simple shell available over the kgdboc connection. You can switch back and forth between kdb or the gdb stub mode of operation dynamically. From gdb stub mode you can blindly type "$3#33", or from the kdb mode you can enter "kgdb" to switch to the gdb stub. The logic in the debug core depends on kdb to look for the typical gdb connection sequences and return immediately with KGDB_PASS_EVENT if a gdb serial command sequence is detected. That should allow a reasonably seamless transition between kdb -> gdb without leaving the kernel exception state. The two gdb serial queries that kdb is responsible for detecting are the "?" and "qSupported" packets. CC: Ingo Molnar <mingo@elte.hu> Signed-off-by: Jason Wessel <jason.wessel@windriver.com> Acked-by: Martin Hicks <mort@sgi.com>
* x86,kgdb: Always initialize the hw breakpoint attributeJason Wessel2010-04-011-1/+1
| | | | | | | | | | | | It is required to call hw_breakpoint_init() on an attr before using it in any other calls. This fixes the problem where kgdb will sometimes fail to initialize on x86_64. Signed-off-by: Jason Wessel <jason.wessel@windriver.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: 2.6.33 <stable@kernel.org> LKML-Reference: <1269975907-27602-1-git-send-email-jason.wessel@windriver.com> Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
* perf, hw_breakpoint, kgdb: Do not take mutex for kernel debuggerJason Wessel2010-01-301-0/+51
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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: Jason Wessel <jason.wessel@windriver.com> Acked-by: Frederic 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: Ingo Molnar <mingo@elte.hu>
* x86, hw_breakpoints, kgdb: Fix kgdb to use hw_breakpoint APIJason Wessel2010-01-301-57/+114
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | In the 2.6.33 kernel, the hw_breakpoint API is now used for the performance event counters. The hw_breakpoint_handler() now consumes the hw breakpoints that were previously set by kgdb arch specific code. In order for kgdb to work in conjunction with this core API change, kgdb must use some of the low level functions of the hw_breakpoint API to install, uninstall, and deal with hw breakpoint reservations. The kgdb core required a change to call kgdb_disable_hw_debug anytime a slave cpu enters kgdb_wait() in order to keep all the hw breakpoints in sync as well as to prevent hitting a hw breakpoint while kgdb is active. During the architecture specific initialization of kgdb, it will pre-allocate 4 disabled (struct perf event **) structures. Kgdb will use these to manage the capabilities for the 4 hw breakpoint registers, per cpu. Right now the hw_breakpoint API does not have a way to ask how many breakpoints are available, on each CPU so it is possible that the install of a breakpoint might fail when kgdb restores the system to the run state. The intent of this patch is to first get the basic functionality of hw breakpoints working and leave it to the person debugging the kernel to understand what hw breakpoints are in use and what restrictions have been imposed as a result. Breakpoint constraints will be dealt with in a future patch. While atomic, the x86 specific kgdb code will call arch_uninstall_hw_breakpoint() and arch_install_hw_breakpoint() to manage the cpu specific hw breakpoints. The net result of these changes allow kgdb to use the same pool of hw_breakpoints that are used by the perf event API, but neither knows about future reservations for the available hw breakpoint slots. Signed-off-by: Jason Wessel <jason.wessel@windriver.com> Acked-by: Frederic 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: <1264719883-7285-2-git-send-email-jason.wessel@windriver.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* kgdb,x86: do not set kgdb_single_step on x86Jason Wessel2009-12-111-1/+0
| | | | | | | | | | | | | | | | | | | | | | | | | | | On an SMP system the kgdb_single_step flag has the possibility to indefinitely hang the system in the case. Consider the case where, CPU 1 has the schedule lock and CPU 0 is set to single step, there is no way for CPU 0 to run another task. The easy way to observe the problem is to make 2 cpus busy, and run the kgdb test suite. You will see that it hangs the system very quickly. while [ 1 ] ; do find /proc > /dev/null 2>&1 ; done & while [ 1 ] ; do find /proc > /dev/null 2>&1 ; done & echo V1 > /sys/module/kgdbts/parameters/kgdbts The side effect of this patch is that there is the possibility to miss a breakpoint in the case that a single step operation was executed to step over a breakpoint in common code. The trade off of the missed breakpoint is preferred to hanging the kernel. This can be fixed in the future by using kprobes or another strategy to step over planted breakpoints with out of line execution. CC: Ingo Molnar <mingo@elte.hu> Signed-off-by: Jason Wessel <jason.wessel@windriver.com>
* kgdb,i386: Fix corner case access to ss with NMI watch dog exceptionJason Wessel2009-12-111-2/+8
| | | | | | | | | | | | | It is possible for the user_mode_vm(regs) check to return true on the i368 arch for a non master kgdb cpu or when the master kgdb cpu handles the NMI watch dog exception. The solution is simply to select the correct gdb_ss location based on the check to user_mode_vm(regs). CC: Ingo Molnar <mingo@elte.hu> Acked-by: H. Peter Anvin <hpa@zytor.com> Signed-off-by: Jason Wessel <jason.wessel@windriver.com>
* kgdb,x86: remove redundant testRoel Kluin2009-12-111-2/+1
| | | | | | | | | The for loop starts with a breakno of 0, and ends when it's 4. so this test is always true. Signed-off-by: Roel Kluin <roel.kluin@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Jason Wessel <jason.wessel@windriver.com>
* Merge branch 'x86-cleanups-for-linus' of ↵Linus Torvalds2009-12-051-2/+1
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip * 'x86-cleanups-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: x86: Fix a section mismatch in arch/x86/kernel/setup.c x86: Fixup last users of irq_chip->typename x86: Remove BKL from apm_32 x86: Remove BKL from microcode x86: use kernel_stack_pointer() in kprobes.c x86: use kernel_stack_pointer() in kgdb.c x86: use kernel_stack_pointer() in dumpstack.c x86: use kernel_stack_pointer() in process_32.c
| * x86: use kernel_stack_pointer() in kgdb.cH. Peter Anvin2009-10-121-2/+1
| | | | | | | | | | | | | | | | | | | | | | | | The way to obtain a kernel-mode stack pointer from a struct pt_regs in 32-bit mode is "subtle": the stack doesn't actually contain the stack pointer, but rather the location where it would have been marks the actual previous stack frame. For clarity, use kernel_stack_pointer() instead of coding this weirdness explicitly. Signed-off-by: H. Peter Anvin <hpa@zytor.com> Cc: Jason Wessel <jason.wessel@windriver.com>
* | Merge branch 'linus' into tracing/hw-breakpointsIngo Molnar2009-06-171-1/+1
|\ \ | |/ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Conflicts: arch/x86/Kconfig arch/x86/kernel/traps.c arch/x86/power/cpu.c arch/x86/power/cpu_32.c kernel/Makefile Semantic conflict: arch/x86/kernel/hw_breakpoint.c Merge reason: Resolve the conflicts, move from put_cpu_no_sched() to put_cpu() in arch/x86/kernel/hw_breakpoint.c. Signed-off-by: Ingo Molnar <mingo@elte.hu>
| * Merge branch 'x86-asm-for-linus' of ↵Linus Torvalds2009-06-101-1/+1
| |\ | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip * 'x86-asm-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: x86, 64-bit: ifdef out struct thread_struct::ip x86, 32-bit: ifdef out struct thread_struct::fs x86: clean up alternative.h
| | * x86, 64-bit: ifdef out struct thread_struct::ipAlexey Dobriyan2009-05-111-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | struct thread_struct::ip isn't used on x86_64, struct pt_regs::ip is used instead. kgdb should be reading 0 always, but I can't check it. [ Impact: (potentially) reduce thread_struct size on 64-bit ] Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com> Cc: containers@lists.linux-foundation.org LKML-Reference: <20090503233015.GJ16631@x200.localdomain> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* | | hw-breakpoints: reset bits in dr6 after the corresponding exception is handledK.Prasad2009-06-021-0/+6
|/ / | | | | | | | | | | | | | | | | | | | | This patch resets the bit in dr6 after the corresponding exception is handled in code, so that we keep a clean track of the current virtual debug status register. [ Impact: keep track of breakpoints triggering completion ] Signed-off-by: K.Prasad <prasad@linux.vnet.ibm.com> Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
* | kgdb,i386: use address that SP register points to in the exception frameJason Wessel2009-05-151-1/+2
|/ | | | | | | | | | | | The treatment of the SP register is different on x86_64 and i386. This is a regression fix that lived outside the mainline kernel from 2.6.27 to now. The regression was a result of the original merge consolidation of the i386 and x86_64 archs to x86. The incorrectly reported SP on i386 prevented stack tracebacks from working correctly in gdb. Signed-off-by: Jason Wessel <jason.wessel@windriver.com>
* x86, apic: remove genapic.hIngo Molnar2009-02-171-1/+1
| | | | | | | | Impact: cleanup Remove genapic.h and remove all references to it. Signed-off-by: Ingo Molnar <mingo@elte.hu>
* x86, smp: remove mach_ipi.hIngo Molnar2009-01-291-1/+1
| | | | | | Move mach_ipi.h definitions into genapic.h. Signed-off-by: Ingo Molnar <mingo@elte.hu>
* x86, apic: untangle the send_IPI_*() jungleIngo Molnar2009-01-281-1/+1
| | | | | | | | | | | | | | | | Our send_IPI_*() methods and definitions are a twisted mess: the same symbol is defined to different things depending on .config details, in a non-transparent way. - spread out the quirks into separately named per apic driver methods - prefix the standard PC methods with default_ - get rid of wrapper macro obfuscation - clean up various details Signed-off-by: Ingo Molnar <mingo@elte.hu>
* kgdb, x86: Avoid invoking kgdb_nmicallback twice per NMIJan Kiszka2008-10-061-6/+1
| | | | | | | | | | | | Stress-testing KVM's latest NMI support with kgdbts inside an SMP guest, I came across spurious unhandled NMIs while running the singlestep test. Looking closer at the code path each NMI takes when KGDB is enabled, I noticed that kgdb_nmicallback is called twice per event: One time via DIE_NMI_IPI notification, the second time on DIE_NMI. Removing the first invocation cures the unhandled NMIs here. Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com> Signed-off-by: Jason Wessel <jason.wessel@windriver.com>
* kgdb, x86_64: fix PS CS SS registers in gdb serialJason Wessel2008-09-261-4/+21
| | | | | | | | | | | | | On x86_64 the gdb serial register structure defines the PS (also known as eflags), CS and SS registers as 4 bytes entities. This patch splits the x86_64 regnames enum into a 32 and 64 version to account for the 32 bit entities in the gdb serial packets. Also the program counter is properly filled in for the sleeping threads. Signed-off-by: Jason Wessel <jason.wessel@windriver.com>
* kgdb, x86, arm, mips, powerpc: ignore user space single steppingJason Wessel2008-09-261-7/+11
| | | | | | | | | | | | | | | | | | | | On the x86 arch, user space single step exceptions should be ignored if they occur in the kernel space, such as ptrace stepping through a system call. First check if it is kgdb that is executing a single step, then ensure it is not an accidental traversal into the user space, while in kgdb, any other time the TIF_SINGLESTEP is set, kgdb should ignore the exception. On x86, arm, mips and powerpc, the kgdb_contthread usage was inconsistent with the way single stepping is implemented in the kgdb core. The arch specific stub should always set the kgdb_cpu_doing_single_step correctly if it is single stepping. This allows kgdb to correctly process an instruction steps if ptrace happens to be requesting an instruction step over a system call. Signed-off-by: Jason Wessel <jason.wessel@windriver.com>
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