powerpc: BookE hardware watchpoint support
This patch implements support for HW based watchpoint via the
DBSR_DAC (Data Address Compare) facility of the BookE processors.
It does so by interfacing with the existing DABR breakpoint code
and adding the necessary bits and pieces for the new bits to
be properly set or cleared
Signed-off-by: Luis Machado <luisgpm@br.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
diff --git a/arch/powerpc/kernel/traps.c b/arch/powerpc/kernel/traps.c
index 878fbdd..81ccb8dd 100644
--- a/arch/powerpc/kernel/traps.c
+++ b/arch/powerpc/kernel/traps.c
@@ -1067,6 +1067,22 @@
}
_exception(SIGTRAP, regs, TRAP_TRACE, regs->nip);
+ } else if (debug_status & (DBSR_DAC1R | DBSR_DAC1W)) {
+ regs->msr &= ~MSR_DE;
+
+ if (user_mode(regs)) {
+ current->thread.dbcr0 &= ~(DBSR_DAC1R | DBSR_DAC1W |
+ DBCR0_IDM);
+ } else {
+ /* Disable DAC interupts */
+ mtspr(SPRN_DBCR0, mfspr(SPRN_DBCR0) & ~(DBSR_DAC1R |
+ DBSR_DAC1W | DBCR0_IDM));
+
+ /* Clear the DAC event */
+ mtspr(SPRN_DBSR, (DBSR_DAC1R | DBSR_DAC1W));
+ }
+ /* Setup and send the trap to the handler */
+ do_dabr(regs, mfspr(SPRN_DAC1), debug_status);
}
}
#endif /* CONFIG_4xx || CONFIG_BOOKE */