powerpc/booke: Add kprobes support for booke style processors
This patch is based on work done by Madhvesh. R. Sulibhavi back in
March 2007.
We refactor some of the single step handling since it differs between
"classic" and "booke" powerpc cores.
Signed-off-by: Kumar Gala <galak@kernel.crashing.org>
diff --git a/arch/powerpc/kernel/kprobes.c b/arch/powerpc/kernel/kprobes.c
index 74693d9..4ba2af1 100644
--- a/arch/powerpc/kernel/kprobes.c
+++ b/arch/powerpc/kernel/kprobes.c
@@ -34,6 +34,13 @@
#include <asm/cacheflush.h>
#include <asm/sstep.h>
#include <asm/uaccess.h>
+#include <asm/system.h>
+
+#ifdef CONFIG_BOOKE
+#define MSR_SINGLESTEP (MSR_DE)
+#else
+#define MSR_SINGLESTEP (MSR_SE)
+#endif
DEFINE_PER_CPU(struct kprobe *, current_kprobe) = NULL;
DEFINE_PER_CPU(struct kprobe_ctlblk, kprobe_ctlblk);
@@ -53,7 +60,8 @@
ret = -EINVAL;
}
- /* insn must be on a special executable page on ppc64 */
+ /* insn must be on a special executable page on ppc64. This is
+ * not explicitly required on ppc32 (right now), but it doesn't hurt */
if (!ret) {
p->ainsn.insn = get_insn_slot();
if (!p->ainsn.insn)
@@ -100,7 +108,11 @@
* possible we'd get the single step reported for an exception handler
* like Decrementer or External Interrupt */
regs->msr &= ~MSR_EE;
- regs->msr |= MSR_SE;
+ regs->msr |= MSR_SINGLESTEP;
+#ifdef CONFIG_BOOKE
+ regs->msr &= ~MSR_CE;
+ mtspr(SPRN_DBCR0, mfspr(SPRN_DBCR0) | DBCR0_IC | DBCR0_IDM);
+#endif
/*
* On powerpc we should single step on the original
@@ -163,7 +175,8 @@
kprobe_opcode_t insn = *p->ainsn.insn;
if (kcb->kprobe_status == KPROBE_HIT_SS &&
is_trap(insn)) {
- regs->msr &= ~MSR_SE;
+ /* Turn off 'trace' bits */
+ regs->msr &= ~MSR_SINGLESTEP;
regs->msr |= kcb->kprobe_saved_msr;
goto no_kprobe;
}
@@ -404,10 +417,10 @@
/*
* if somebody else is singlestepping across a probe point, msr
- * will have SE set, in which case, continue the remaining processing
+ * will have DE/SE set, in which case, continue the remaining processing
* of do_debug, as if this is not a probe hit.
*/
- if (regs->msr & MSR_SE)
+ if (regs->msr & MSR_SINGLESTEP)
return 0;
return 1;
@@ -430,7 +443,7 @@
* normal page fault.
*/
regs->nip = (unsigned long)cur->addr;
- regs->msr &= ~MSR_SE;
+ regs->msr &= ~MSR_SINGLESTEP; /* Turn off 'trace' bits */
regs->msr |= kcb->kprobe_saved_msr;
if (kcb->kprobe_status == KPROBE_REENTER)
restore_previous_kprobe(kcb);