powerpc/booke: Add kprobes support for booke style processors

[pandora-kernel.git] / arch / powerpc / kernel / kprobes.c

diff --git a/arch/powerpc/kernel/kprobes.c b/arch/powerpc/kernel/kprobes.c
index 74693d9..4ba2af1 100644 (file)
--- 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 @@ int __kprobes arch_prepare_kprobe(struct kprobe *p)
                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 @@ static void __kprobes prepare_singlestep(struct kprobe *p, struct pt_regs *regs)
         * 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 @@ static int __kprobes kprobe_handler(struct pt_regs *regs)
                        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 @@ out:
 
        /*
         * 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 @@ int __kprobes kprobe_fault_handler(struct pt_regs *regs, int trapnr)
                 * 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);