Message ID | 20100525091435.GD29003@in.ibm.com (mailing list archive) |
---|---|
State | Superseded |
Headers | show |
On Tue, May 25, 2010 at 02:44:35PM +0530, K.Prasad wrote: > An alignment interrupt may intervene between a DSI/hw-breakpoint exception > and the single-step exception. Enable the alignment interrupt (through > modifications to emulate_single_step()) to notify the single-step exception > handler for proper restoration of hw-breakpoints. > > Signed-off-by: K.Prasad <prasad@linux.vnet.ibm.com> > --- > arch/powerpc/kernel/traps.c | 7 ++----- > 1 file changed, 2 insertions(+), 5 deletions(-) > > Index: linux-2.6.ppc64_test/arch/powerpc/kernel/traps.c > =================================================================== > --- linux-2.6.ppc64_test.orig/arch/powerpc/kernel/traps.c > +++ linux-2.6.ppc64_test/arch/powerpc/kernel/traps.c > @@ -602,7 +602,7 @@ void RunModeException(struct pt_regs *re > > void __kprobes single_step_exception(struct pt_regs *regs) > { > - regs->msr &= ~(MSR_SE | MSR_BE); /* Turn off 'trace' bits */ > + clear_single_step(regs); > > if (notify_die(DIE_SSTEP, "single_step", regs, 5, > 5, SIGTRAP) == NOTIFY_STOP) > @@ -621,10 +621,7 @@ void __kprobes single_step_exception(str > */ > static void emulate_single_step(struct pt_regs *regs) > { > - if (single_stepping(regs)) { > - clear_single_step(regs); > - _exception(SIGTRAP, regs, TRAP_TRACE, 0); > - } > + single_step_exception(regs); > } We still need the if (single_stepping(regs)) in emulate_single_step. We don't want to send the process a SIGTRAP every time it gets an alignment interrupt. :) Paul.
On Thu, May 27, 2010 at 04:20:44PM +1000, Paul Mackerras wrote: > On Tue, May 25, 2010 at 02:44:35PM +0530, K.Prasad wrote: > > > An alignment interrupt may intervene between a DSI/hw-breakpoint exception > > and the single-step exception. Enable the alignment interrupt (through > > modifications to emulate_single_step()) to notify the single-step exception > > handler for proper restoration of hw-breakpoints. > > > > Signed-off-by: K.Prasad <prasad@linux.vnet.ibm.com> > > --- > > arch/powerpc/kernel/traps.c | 7 ++----- > > 1 file changed, 2 insertions(+), 5 deletions(-) > > > > Index: linux-2.6.ppc64_test/arch/powerpc/kernel/traps.c > > =================================================================== > > --- linux-2.6.ppc64_test.orig/arch/powerpc/kernel/traps.c > > +++ linux-2.6.ppc64_test/arch/powerpc/kernel/traps.c > > @@ -602,7 +602,7 @@ void RunModeException(struct pt_regs *re > > > > void __kprobes single_step_exception(struct pt_regs *regs) > > { > > - regs->msr &= ~(MSR_SE | MSR_BE); /* Turn off 'trace' bits */ > > + clear_single_step(regs); > > > > if (notify_die(DIE_SSTEP, "single_step", regs, 5, > > 5, SIGTRAP) == NOTIFY_STOP) > > @@ -621,10 +621,7 @@ void __kprobes single_step_exception(str > > */ > > static void emulate_single_step(struct pt_regs *regs) > > { > > - if (single_stepping(regs)) { > > - clear_single_step(regs); > > - _exception(SIGTRAP, regs, TRAP_TRACE, 0); > > - } > > + single_step_exception(regs); > > } > > We still need the if (single_stepping(regs)) in emulate_single_step. > We don't want to send the process a SIGTRAP every time it gets an > alignment interrupt. :) > > Paul. Agreed, and made changes to that effect in version XXII (as seen in patch linuxppc-dev message-id: 20100528064017.GD8679@in.ibm.com). Thanks, K.Prasad
Index: linux-2.6.ppc64_test/arch/powerpc/kernel/traps.c =================================================================== --- linux-2.6.ppc64_test.orig/arch/powerpc/kernel/traps.c +++ linux-2.6.ppc64_test/arch/powerpc/kernel/traps.c @@ -602,7 +602,7 @@ void RunModeException(struct pt_regs *re void __kprobes single_step_exception(struct pt_regs *regs) { - regs->msr &= ~(MSR_SE | MSR_BE); /* Turn off 'trace' bits */ + clear_single_step(regs); if (notify_die(DIE_SSTEP, "single_step", regs, 5, 5, SIGTRAP) == NOTIFY_STOP) @@ -621,10 +621,7 @@ void __kprobes single_step_exception(str */ static void emulate_single_step(struct pt_regs *regs) { - if (single_stepping(regs)) { - clear_single_step(regs); - _exception(SIGTRAP, regs, TRAP_TRACE, 0); - } + single_step_exception(regs); } static inline int __parse_fpscr(unsigned long fpscr)
An alignment interrupt may intervene between a DSI/hw-breakpoint exception and the single-step exception. Enable the alignment interrupt (through modifications to emulate_single_step()) to notify the single-step exception handler for proper restoration of hw-breakpoints. Signed-off-by: K.Prasad <prasad@linux.vnet.ibm.com> --- arch/powerpc/kernel/traps.c | 7 ++----- 1 file changed, 2 insertions(+), 5 deletions(-)