- 30 1月, 2010 2 次提交
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由 Jason Wessel 提交于
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: NJason Wessel <jason.wessel@windriver.com> Acked-by: NFrederic 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: NIngo Molnar <mingo@elte.hu>
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由 Jason Wessel 提交于
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: NJason Wessel <jason.wessel@windriver.com> Acked-by: NFrederic 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: NIngo Molnar <mingo@elte.hu>
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- 11 12月, 2009 3 次提交
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由 Jason Wessel 提交于
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: NJason Wessel <jason.wessel@windriver.com>
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由 Jason Wessel 提交于
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: NH. Peter Anvin <hpa@zytor.com> Signed-off-by: NJason Wessel <jason.wessel@windriver.com>
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由 Roel Kluin 提交于
The for loop starts with a breakno of 0, and ends when it's 4. so this test is always true. Signed-off-by: NRoel Kluin <roel.kluin@gmail.com> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NJason Wessel <jason.wessel@windriver.com>
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- 13 10月, 2009 1 次提交
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由 H. Peter Anvin 提交于
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: NH. Peter Anvin <hpa@zytor.com> Cc: Jason Wessel <jason.wessel@windriver.com>
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- 03 6月, 2009 1 次提交
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由 K.Prasad 提交于
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: NK.Prasad <prasad@linux.vnet.ibm.com> Signed-off-by: NFrederic Weisbecker <fweisbec@gmail.com>
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- 15 5月, 2009 1 次提交
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由 Jason Wessel 提交于
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: NJason Wessel <jason.wessel@windriver.com>
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- 11 5月, 2009 1 次提交
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由 Alexey Dobriyan 提交于
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: NAlexey Dobriyan <adobriyan@gmail.com> Cc: containers@lists.linux-foundation.org LKML-Reference: <20090503233015.GJ16631@x200.localdomain> Signed-off-by: NIngo Molnar <mingo@elte.hu>
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- 18 2月, 2009 1 次提交
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由 Ingo Molnar 提交于
Impact: cleanup Remove genapic.h and remove all references to it. Signed-off-by: NIngo Molnar <mingo@elte.hu>
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- 29 1月, 2009 2 次提交
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由 Ingo Molnar 提交于
Move mach_ipi.h definitions into genapic.h. Signed-off-by: NIngo Molnar <mingo@elte.hu>
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由 Ingo Molnar 提交于
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: NIngo Molnar <mingo@elte.hu>
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- 07 10月, 2008 1 次提交
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由 Jan Kiszka 提交于
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: NJan Kiszka <jan.kiszka@siemens.com> Signed-off-by: NJason Wessel <jason.wessel@windriver.com>
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- 26 9月, 2008 2 次提交
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由 Jason Wessel 提交于
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: NJason Wessel <jason.wessel@windriver.com>
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由 Jason Wessel 提交于
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: NJason Wessel <jason.wessel@windriver.com>
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- 20 4月, 2008 1 次提交
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由 Ingo Molnar 提交于
Signed-off-by: NIngo Molnar <mingo@elte.hu>
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- 19 4月, 2008 1 次提交
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由 Harvey Harrison 提交于
TF_MASK is no longer defined, use X86_EFLAGS_TF. Signed-off-by: NHarvey Harrison <harvey.harrison@gmail.com> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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- 18 4月, 2008 4 次提交
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由 Jason Wessel 提交于
kgdb core fixes: - Check to see that mm->mmap_cache is not null before calling flush_cache_range(), else on arch=ARM it will cause a fatal fault. - Breakpoints should only be restored if they are in the BP_ACTIVE state. - Fix a typo in comments to "kgdb_register_io_module" x86 kgdb fixes: - Fix the x86 arch handler such that on a kill or detach that the appropriate cleanup on the single stepping flags gets run. - Add in the DIE_NMIWATCHDOG call for x86_64 - Touch the nmi watchdog before returning the system to normal operation after performing any kind of kgdb operation, else the possibility exists to trigger the watchdog. Signed-off-by: NJason Wessel <jason.wessel@windriver.com> Signed-off-by: NIngo Molnar <mingo@elte.hu>
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由 Jason Wessel 提交于
Add HW breakpoints into the arch specific portion of x86 kgdb. In the current x86 kernel.org kernels HW breakpoints are changed out in lazy fashion because there is no infrastructure around changing them when changing to a kernel task or entering the kernel mode via a system call. This lazy approach means that if a user process uses HW breakpoints the kgdb will loose out. This is an acceptable trade off because the developer debugging the kernel is assumed to know what is going on system wide and would be aware of this trade off. There is a minor bug fix to the kgdb core so as to correctly call the hw breakpoint functions with a valid value from the enum. There is also a minor change to the x86_64 startup code when using early HW breakpoints. When the debugger is connected, the cpu startup code must not zero out the HW breakpoint registers or you cannot hit the breakpoints you are interested in, in the first place. Signed-off-by: NJason Wessel <jason.wessel@windriver.com> Signed-off-by: NIngo Molnar <mingo@elte.hu>
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由 Jason Wessel 提交于
This patch fixes the hang regression with kgdb when the NMI interrupt comes in while the master core is returning from an exception. Adjust the NMI logic such that KGDB will not stop NMI exceptions from occurring by in general returning NOTIFY_DONE. It is not possible to distinguish the debug NMI sync vs the normal NMI apic interrupt so kgdb needs to catch the unknown NMI if it the debugger was previously active on one of the cpus. Signed-off-by: NJason Wessel <jason.wessel@windriver.com> Signed-off-by: NIngo Molnar <mingo@elte.hu>
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由 Ingo Molnar 提交于
simplified and streamlined kgdb support on x86, both 32-bit and 64-bit, based on patch from: Subject: kgdb: core-lite From: Jason Wessel <jason.wessel@windriver.com> [ and countless other authors - see the patch for details. ] Signed-off-by: NIngo Molnar <mingo@elte.hu> Signed-off-by: NJason Wessel <jason.wessel@windriver.com> Signed-off-by: NJan Kiszka <jan.kiszka@web.de> Reviewed-by: NThomas Gleixner <tglx@linutronix.de>
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