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 <pra...@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.
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