* [PATCH 1/3] kgdb,ppc: do not set kgdb_single_step on ppc @ 2012-08-22 10:43 Tiejun Chen 2012-08-22 10:43 ` [PATCH 2/3] powerpc: Bail out of KGDB when we've been triggered Tiejun Chen 2012-08-22 10:43 ` [PATCH 3/3] powerpc/kgdb: restore current_thread_info properly Tiejun Chen 0 siblings, 2 replies; 5+ messages in thread From: Tiejun Chen @ 2012-08-22 10:43 UTC (permalink / raw) To: benh; +Cc: linuxppc-dev, linux-kernel, jason.wessel The kgdb_single_step flag has the possibility to indefinitely hang the system on an SMP system. The x86 arch have the same problem, and that problem was fixed by commit 8097551d9ab9b9e3630(kgdb,x86: do not set kgdb_single_step on x86). This patch does the same behaviors as x86's patch. Signed-off-by: Dongdong Deng <dongdong.deng@windriver.com> Signed-off-by: Jason Wessel <jason.wessel@windriver.com> Signed-off-by: Tiejun Chen <tiejun.chen@windriver.com> --- arch/powerpc/kernel/kgdb.c | 1 - 1 files changed, 0 insertions(+), 1 deletions(-) diff --git a/arch/powerpc/kernel/kgdb.c b/arch/powerpc/kernel/kgdb.c index 782bd0a..bbabc5a 100644 --- a/arch/powerpc/kernel/kgdb.c +++ b/arch/powerpc/kernel/kgdb.c @@ -410,7 +410,6 @@ int kgdb_arch_handle_exception(int vector, int signo, int err_code, #else linux_regs->msr |= MSR_SE; #endif - kgdb_single_step = 1; atomic_set(&kgdb_cpu_doing_single_step, raw_smp_processor_id()); } -- 1.5.6 ^ permalink raw reply related [flat|nested] 5+ messages in thread
* [PATCH 2/3] powerpc: Bail out of KGDB when we've been triggered 2012-08-22 10:43 [PATCH 1/3] kgdb,ppc: do not set kgdb_single_step on ppc Tiejun Chen @ 2012-08-22 10:43 ` Tiejun Chen 2012-08-22 15:07 ` Tabi Timur-B04825 2012-08-22 10:43 ` [PATCH 3/3] powerpc/kgdb: restore current_thread_info properly Tiejun Chen 1 sibling, 1 reply; 5+ messages in thread From: Tiejun Chen @ 2012-08-22 10:43 UTC (permalink / raw) To: benh; +Cc: linuxppc-dev, linux-kernel, jason.wessel We need to skip a breakpoint exception when it occurs after a breakpoint has already been removed. Signed-off-by: Tiejun Chen <tiejun.chen@windriver.com> --- arch/powerpc/kernel/kgdb.c | 18 ++++++++++++++++++ 1 files changed, 18 insertions(+), 0 deletions(-) diff --git a/arch/powerpc/kernel/kgdb.c b/arch/powerpc/kernel/kgdb.c index bbabc5a..e84252b 100644 --- a/arch/powerpc/kernel/kgdb.c +++ b/arch/powerpc/kernel/kgdb.c @@ -101,6 +101,24 @@ static int computeSignal(unsigned int tt) return SIGHUP; /* default for things we don't know about */ } +/** + * + * kgdb_skipexception - Bail out of KGDB when we've been triggered. + * @exception: Exception vector number + * @regs: Current &struct pt_regs. + * + * On some architectures we need to skip a breakpoint exception when + * it occurs after a breakpoint has been removed. + * + */ +int kgdb_skipexception(int exception, struct pt_regs *regs) +{ + if (kgdb_isremovedbreak(regs->nip)) + return 1; + + return 0; +} + static int kgdb_call_nmi_hook(struct pt_regs *regs) { kgdb_nmicallback(raw_smp_processor_id(), regs); -- 1.5.6 ^ permalink raw reply related [flat|nested] 5+ messages in thread
* Re: [PATCH 2/3] powerpc: Bail out of KGDB when we've been triggered 2012-08-22 10:43 ` [PATCH 2/3] powerpc: Bail out of KGDB when we've been triggered Tiejun Chen @ 2012-08-22 15:07 ` Tabi Timur-B04825 2012-08-23 1:54 ` tiejun.chen 0 siblings, 1 reply; 5+ messages in thread From: Tabi Timur-B04825 @ 2012-08-22 15:07 UTC (permalink / raw) To: Tiejun Chen; +Cc: linuxppc-dev, linux-kernel, jason.wessel On Wed, Aug 22, 2012 at 5:43 AM, Tiejun Chen <tiejun.chen@windriver.com> wr= ote: > +int kgdb_skipexception(int exception, struct pt_regs *regs) > +{ > + if (kgdb_isremovedbreak(regs->nip)) > + return 1; > + > + return 0; > +} int kgdb_skipexception(int exception, struct pt_regs *regs) { return !!kgdb_isremovedbreak(regs->nip)); } If the caller only cares about zero vs. non-zero, you can drop the !!. --=20 Timur Tabi Linux kernel developer at Freescale= ^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH 2/3] powerpc: Bail out of KGDB when we've been triggered 2012-08-22 15:07 ` Tabi Timur-B04825 @ 2012-08-23 1:54 ` tiejun.chen 0 siblings, 0 replies; 5+ messages in thread From: tiejun.chen @ 2012-08-23 1:54 UTC (permalink / raw) To: Tabi Timur-B04825; +Cc: linuxppc-dev, linux-kernel, jason.wessel On 08/22/2012 11:07 PM, Tabi Timur-B04825 wrote: > On Wed, Aug 22, 2012 at 5:43 AM, Tiejun Chen <tiejun.chen@windriver.com> wrote: > >> +int kgdb_skipexception(int exception, struct pt_regs *regs) >> +{ >> + if (kgdb_isremovedbreak(regs->nip)) >> + return 1; >> + >> + return 0; >> +} > > int kgdb_skipexception(int exception, struct pt_regs *regs) > { > return !!kgdb_isremovedbreak(regs->nip)); > } > > If the caller only cares about zero vs. non-zero, you can drop the !!. Yes, so 'return kgdb_isremovedbreak(regs->nip);' is already fine and simple. I'll update this as v2 so thanks your comment. Tiejun ^ permalink raw reply [flat|nested] 5+ messages in thread
* [PATCH 3/3] powerpc/kgdb: restore current_thread_info properly 2012-08-22 10:43 [PATCH 1/3] kgdb,ppc: do not set kgdb_single_step on ppc Tiejun Chen 2012-08-22 10:43 ` [PATCH 2/3] powerpc: Bail out of KGDB when we've been triggered Tiejun Chen @ 2012-08-22 10:43 ` Tiejun Chen 1 sibling, 0 replies; 5+ messages in thread From: Tiejun Chen @ 2012-08-22 10:43 UTC (permalink / raw) To: benh; +Cc: linuxppc-dev, linux-kernel, jason.wessel For powerpc BooKE and e200, singlestep is handled on the critical/dbg exception stack. This causes current_thread_info() to fail for kgdb internal, so previously We work around this issue by copying the thread_info from the kernel stack before calling kgdb_handle_exception, and copying it back afterwards. But actually we don't do this previously. We should backp current_thread_info then restore that when exit. CC: Jason Wessel <jason.wessel@windriver.com> Signed-off-by: Tiejun Chen <tiejun.chen@windriver.com> --- arch/powerpc/kernel/kgdb.c | 11 +++++++++-- 1 files changed, 9 insertions(+), 2 deletions(-) diff --git a/arch/powerpc/kernel/kgdb.c b/arch/powerpc/kernel/kgdb.c index e84252b..7dcdbe7 100644 --- a/arch/powerpc/kernel/kgdb.c +++ b/arch/powerpc/kernel/kgdb.c @@ -25,6 +25,7 @@ #include <asm/processor.h> #include <asm/machdep.h> #include <asm/debug.h> +#include <linux/slab.h> /* * This table contains the mapping between PowerPC hardware trap types, and @@ -156,6 +157,8 @@ static int kgdb_handle_breakpoint(struct pt_regs *regs) static int kgdb_singlestep(struct pt_regs *regs) { struct thread_info *thread_info, *exception_thread_info; + struct thread_info *backup_current_thread_info = \ + (struct thread_info *)kmalloc(sizeof(struct thread_info), GFP_KERNEL); if (user_mode(regs)) return 0; @@ -173,13 +176,17 @@ static int kgdb_singlestep(struct pt_regs *regs) thread_info = (struct thread_info *)(regs->gpr[1] & ~(THREAD_SIZE-1)); exception_thread_info = current_thread_info(); - if (thread_info != exception_thread_info) + if (thread_info != exception_thread_info) { + /* Save the original current_thread_info. */ + memcpy(backup_current_thread_info, exception_thread_info, sizeof *thread_info); memcpy(exception_thread_info, thread_info, sizeof *thread_info); + } kgdb_handle_exception(0, SIGTRAP, 0, regs); if (thread_info != exception_thread_info) - memcpy(thread_info, exception_thread_info, sizeof *thread_info); + /* Restore current_thread_info lastly. */ + memcpy(exception_thread_info, backup_current_thread_info, sizeof *thread_info); return 1; } -- 1.5.6 ^ permalink raw reply related [flat|nested] 5+ messages in thread
end of thread, other threads:[~2012-08-23 2:02 UTC | newest] Thread overview: 5+ messages (download: mbox.gz / follow: Atom feed) -- links below jump to the message on this page -- 2012-08-22 10:43 [PATCH 1/3] kgdb,ppc: do not set kgdb_single_step on ppc Tiejun Chen 2012-08-22 10:43 ` [PATCH 2/3] powerpc: Bail out of KGDB when we've been triggered Tiejun Chen 2012-08-22 15:07 ` Tabi Timur-B04825 2012-08-23 1:54 ` tiejun.chen 2012-08-22 10:43 ` [PATCH 3/3] powerpc/kgdb: restore current_thread_info properly Tiejun Chen
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