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2008-10-06kgdb: call touch_softlockup_watchdog on resumeJason Wessel
The softlockup watchdog needs to be touched when resuming the from the kgdb stopped state to avoid the printk that a CPU is stuck if the debugger was active for longer than the softlockup threshold. Signed-off-by: Jason Wessel <jason.wessel@windriver.com>
2008-09-26kgdb, x86, arm, mips, powerpc: ignore user space single steppingJason Wessel
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>
2008-09-26kgdb: could not write to the last of valid memory with kgdbAtsuo Igarashi
On the ARM architecture, kgdb will crash the kernel if the last byte of valid memory is written due to a flush_icache_range flushing beyond the memory boundary. Signed-off-by: Atsuo Igarashi <atsuo_igarashi@tripeaks.co.jp> Signed-off-by: Jason Wessel <jason.wessel@windriver.com>
2008-08-01kgdb: fix gdb serial thread queriesJason Wessel
The command "info threads" did not work correctly with kgdb. It would result in a silent kernel hang if used. This patach addresses several problems. - Fix use of deprecated NR_CPUS - Fix kgdb to not walk linearly through the pid space - Correctly implement shadow pids - Change the threads per query to a #define - Fix kgdb_hex2long to work with negated values The threads 0 and -1 are reserved to represent the current task. That means that CPU 0 will start with a shadow thread id of -2, and CPU 1 will have a shadow thread id of -3, etc... From the debugger you can switch to a shadow thread to see what one of the other cpus was doing, however it is not possible to execute run control operations on any other cpu execept the cpu executing the kgdb_handle_exception(). Signed-off-by: Jason Wessel <jason.wessel@windriver.com>
2008-08-01kgdb: fix kgdb_validate_break_address to perform a mem writeJason Wessel
A regression to the kgdb core was found in the case of using the CONFIG_DEBUG_RODATA kernel option. When this option is on, a breakpoint cannot be written into any readonly memory page. When an external debugger requests a breakpoint to get set, the kgdb_validate_break_address() was only checking to see if the address to place the breakpoint was readable and lacked a write check. This patch changes the validate routine to try reading (via the breakpoint set request) and also to try immediately writing the break point. If either fails, an error is correctly returned and the debugger behaves correctly. Then an end user can make the descision to use hardware breakpoints. Also update the documentation to reflect that using CONFIG_DEBUG_RODATA will inhibit the use of software breakpoints. Signed-off-by: Jason Wessel <jason.wessel@windriver.com>
2008-06-24kgdb: sparse fixJason Wessel
- Fix warning reported by sparse kernel/kgdb.c:1502:6: warning: symbol 'kgdb_console_write' was not declared. Should it be static? Signed-off-by: Jason Wessel <jason.wessel@windriver.com>
2008-05-28kgdb: use common ascii helpers and put_unaligned_be32 helperHarvey Harrison
Signed-off-by: Harvey Harrison <harvey.harrison@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Jason Wessel <jason.wessel@windriver.com>
2008-05-14lib: create common ascii hex arrayHarvey Harrison
Add a common hex array in hexdump.c so everyone can use it. Add a common hi/lo helper to avoid the shifting masking that is done to get the upper and lower nibbles of a byte value. Pull the pack_hex_byte helper from kgdb as it is opencoded many places in the tree that will be consolidated. Signed-off-by: Harvey Harrison <harvey.harrison@gmail.com> Acked-by: Paul Mundt <lethal@linux-sh.org> Cc: Jason Wessel <jason.wessel@windriver.com> Cc: Ingo Molnar <mingo@elte.hu> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-05-05kgdb: fix signedness mixmatches, add statics, add declaration to headerHarvey Harrison
Noticed by sparse: arch/x86/kernel/kgdb.c:556:15: warning: symbol 'kgdb_arch_pc' was not declared. Should it be static? kernel/kgdb.c:149:8: warning: symbol 'kgdb_do_roundup' was not declared. Should it be static? kernel/kgdb.c:193:22: warning: symbol 'kgdb_arch_pc' was not declared. Should it be static? kernel/kgdb.c:712:5: warning: symbol 'remove_all_break' was not declared. Should it be static? Related to kgdb_hex2long: arch/x86/kernel/kgdb.c:371:28: warning: incorrect type in argument 2 (different signedness) arch/x86/kernel/kgdb.c:371:28: expected long *long_val arch/x86/kernel/kgdb.c:371:28: got unsigned long *<noident> kernel/kgdb.c:469:27: warning: incorrect type in argument 2 (different signedness) kernel/kgdb.c:469:27: expected long *long_val kernel/kgdb.c:469:27: got unsigned long *<noident> kernel/kgdb.c:470:27: warning: incorrect type in argument 2 (different signedness) kernel/kgdb.c:470:27: expected long *long_val kernel/kgdb.c:470:27: got unsigned long *<noident> kernel/kgdb.c:894:27: warning: incorrect type in argument 2 (different signedness) kernel/kgdb.c:894:27: expected long *long_val kernel/kgdb.c:894:27: got unsigned long *<noident> kernel/kgdb.c:895:27: warning: incorrect type in argument 2 (different signedness) kernel/kgdb.c:895:27: expected long *long_val kernel/kgdb.c:895:27: got unsigned long *<noident> kernel/kgdb.c:1127:28: warning: incorrect type in argument 2 (different signedness) kernel/kgdb.c:1127:28: expected long *long_val kernel/kgdb.c:1127:28: got unsigned long *<noident> kernel/kgdb.c:1132:25: warning: incorrect type in argument 2 (different signedness) kernel/kgdb.c:1132:25: expected long *long_val kernel/kgdb.c:1132:25: got unsigned long *<noident> Signed-off-by: Harvey Harrison <harvey.harrison@gmail.com> Signed-off-by: Jason Wessel <jason.wessel@windriver.com>
2008-04-17kgdb: always use icache flush for sw breakpointsJason Wessel
On the ppc 4xx architecture the instruction cache must be flushed as well as the data cache. This patch just makes it generic for all architectures where CACHE_FLUSH_IS_SAFE is set to 1. Signed-off-by: Jason Wessel <jason.wessel@windriver.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-04-17kgdb: fix SMP NMI kgdb_handle_exception exit raceJason Wessel
Fix the problem of protecting the kgdb handle_exception exit which had an NMI race condition, while trying to restore normal system operation. There was a small window after the master processor sets cpu_in_debug to zero but before it has set kgdb_active to zero where a non-master processor in an SMP system could receive an NMI and re-enter the kgdb_wait() loop. As long as the master processor sets the cpu_in_debug before sending the cpu roundup the cpu_in_debug variable can also be used to guard against the race condition. The kgdb_wait() function no longer needs to check kgdb_active because it is done in the arch specific code and handled along with the nmi traps at the low level. This also allows kgdb_wait() to exit correctly if it was entered for some unknown reason due to a spurious NMI that could not be handled by the arch specific code. Signed-off-by: Jason Wessel <jason.wessel@windriver.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-04-17kgdb: fix several kgdb regressionsJason Wessel
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: Jason Wessel <jason.wessel@windriver.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-04-17kgdb: fix optional arch functions and probe_kernel_*Jason Wessel
Fix two regressions dealing with the kgdb core. 1) kgdb_skipexception and kgdb_post_primary_code are optional functions that are only required on archs that need special exception fixups. 2) The kernel address space scope must be set on any probe_kernel_* function or archs such as ARCH=arm will not allow access to the kernel memory space. As an example, it is required to allow the full kernel address space is when you the kernel debugger to inspect a system call. Signed-off-by: Jason Wessel <jason.wessel@windriver.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-04-17kgdb: add x86 HW breakpointsJason Wessel
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: Jason Wessel <jason.wessel@windriver.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-04-17kgdb: print breakpoint removed on exceptionJason Wessel
If kgdb does remove a breakpoint that had a problem on the recursion check, it should also print the address of the breakpoint. Signed-off-by: Jason Wessel <jason.wessel@windriver.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-04-17kgdb: clocksource watchdogJason Wessel
In order to not trip the clocksource watchdog, kgdb must touch the clocksource watchdog on the return to normal system run state. Signed-off-by: Jason Wessel <jason.wessel@windriver.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-04-17kgdb: coreJason Wessel
kgdb core code. Handles the protocol and the arch details. [ mingo@elte.hu: heavily modified, simplified and cleaned up. ] [ xemul@openvz.org: use find_task_by_pid_ns ] Signed-off-by: Jason Wessel <jason.wessel@windriver.com> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Jan Kiszka <jan.kiszka@web.de> Reviewed-by: Thomas Gleixner <tglx@linutronix.de>