| Message ID | 1350528455-4751-1-git-send-email-tiejun.chen@windriver.com (mailing list archive) |
|---|---|
| State | Superseded |
| Headers | show |
Please ignore v2 temporarily since I have to correct something lately. Sorry for any inconvenience. Tiejun On 10/18/2012 10:47 AM, Tiejun Chen wrote: > When we're in kgdb_singlestep(), we have to work around to get > thread_info by copying from the kernel stack before calling > kgdb_handle_exception(), then copying it back afterwards. > > But for PPC64, we have a lazy interrupt implementation. So after > copying thread info frome kernle stack, if we need to replay an > interrupt, we shouldn't restore that previous backup thread info > to make sure we can replay an interrupt lately with a proper > thread info. > > This patch use __check_irq_replay() to guarantee this process. > > Signed-off-by: Tiejun Chen <tiejun.chen@windriver.com> > --- > arch/powerpc/kernel/irq.c | 12 +++++++++++- > arch/powerpc/kernel/kgdb.c | 7 ++++--- > 2 files changed, 15 insertions(+), 4 deletions(-) > > diff --git a/arch/powerpc/kernel/irq.c b/arch/powerpc/kernel/irq.c > index 71413f4..a773789 100644 > --- a/arch/powerpc/kernel/irq.c > +++ b/arch/powerpc/kernel/irq.c > @@ -332,7 +332,17 @@ bool prep_irq_for_idle(void) > return true; > } > > -#endif /* CONFIG_PPC64 */ > +notrace unsigned int check_irq_replay(void) > +{ > + return __check_irq_replay(); > +} > +#else /* CONFIG_PPC64 */ > +notrace unsigned int check_irq_replay(void) > +{ > + return 0; > +} > +#endif /* !CONFIG_PPC64 */ > +EXPORT_SYMBOL(check_irq_replay); > > int arch_show_interrupts(struct seq_file *p, int prec) > { > diff --git a/arch/powerpc/kernel/kgdb.c b/arch/powerpc/kernel/kgdb.c > index c470a40..c4af341 100644 > --- a/arch/powerpc/kernel/kgdb.c > +++ b/arch/powerpc/kernel/kgdb.c > @@ -151,6 +151,7 @@ static int kgdb_handle_breakpoint(struct pt_regs *regs) > return 1; > } > > +extern notrace unsigned int check_irq_replay(void); > static int kgdb_singlestep(struct pt_regs *regs) > { > struct thread_info *thread_info, *exception_thread_info; > @@ -181,9 +182,9 @@ static int kgdb_singlestep(struct pt_regs *regs) > > kgdb_handle_exception(0, SIGTRAP, 0, regs); > > - if (thread_info != exception_thread_info) > - /* Restore current_thread_info lastly. */ > - memcpy(exception_thread_info, backup_current_thread_info, sizeof *thread_info); > + if ((thread_info != exception_thread_info) && (!check_irq_replay())) > + /* Restore current_thread_info lastly only if we don't replay interrupt. */ > + memcpy(exception_thread_info, backup_current_thread_info, sizeof *thread_info); > > return 1; > } >
diff --git a/arch/powerpc/kernel/irq.c b/arch/powerpc/kernel/irq.c index 71413f4..a773789 100644 --- a/arch/powerpc/kernel/irq.c +++ b/arch/powerpc/kernel/irq.c @@ -332,7 +332,17 @@ bool prep_irq_for_idle(void) return true; } -#endif /* CONFIG_PPC64 */ +notrace unsigned int check_irq_replay(void) +{ + return __check_irq_replay(); +} +#else /* CONFIG_PPC64 */ +notrace unsigned int check_irq_replay(void) +{ + return 0; +} +#endif /* !CONFIG_PPC64 */ +EXPORT_SYMBOL(check_irq_replay); int arch_show_interrupts(struct seq_file *p, int prec) { diff --git a/arch/powerpc/kernel/kgdb.c b/arch/powerpc/kernel/kgdb.c index c470a40..c4af341 100644 --- a/arch/powerpc/kernel/kgdb.c +++ b/arch/powerpc/kernel/kgdb.c @@ -151,6 +151,7 @@ static int kgdb_handle_breakpoint(struct pt_regs *regs) return 1; } +extern notrace unsigned int check_irq_replay(void); static int kgdb_singlestep(struct pt_regs *regs) { struct thread_info *thread_info, *exception_thread_info; @@ -181,9 +182,9 @@ static int kgdb_singlestep(struct pt_regs *regs) kgdb_handle_exception(0, SIGTRAP, 0, regs); - if (thread_info != exception_thread_info) - /* Restore current_thread_info lastly. */ - memcpy(exception_thread_info, backup_current_thread_info, sizeof *thread_info); + if ((thread_info != exception_thread_info) && (!check_irq_replay())) + /* Restore current_thread_info lastly only if we don't replay interrupt. */ + memcpy(exception_thread_info, backup_current_thread_info, sizeof *thread_info); return 1; }
When we're in kgdb_singlestep(), we have to work around to get thread_info by copying from the kernel stack before calling kgdb_handle_exception(), then copying it back afterwards. But for PPC64, we have a lazy interrupt implementation. So after copying thread info frome kernle stack, if we need to replay an interrupt, we shouldn't restore that previous backup thread info to make sure we can replay an interrupt lately with a proper thread info. This patch use __check_irq_replay() to guarantee this process. Signed-off-by: Tiejun Chen <tiejun.chen@windriver.com> --- arch/powerpc/kernel/irq.c | 12 +++++++++++- arch/powerpc/kernel/kgdb.c | 7 ++++--- 2 files changed, 15 insertions(+), 4 deletions(-)