---
Here's a cleaned up version of my patch incorporating the changes we've
discussed and some minor tweaks to traps.c. Can you take a look and test
it out. I'm wondering about having to clear MSR_EE & MSR_CE in
prepare_singlestep(). Doesnt seem like we need to do that at all.
- k
Documentation/kprobes.txt | 1 +
arch/powerpc/kernel/kprobes.c | 23 +++++++++++++++++++----
arch/powerpc/kernel/misc_32.S | 2 +-
arch/powerpc/kernel/traps.c | 32 +++++++++++++++++---------------
include/asm-powerpc/system.h | 9 +++++++++
5 files changed, 47 insertions(+), 20 deletions(-)
diff --git a/Documentation/kprobes.txt b/Documentation/kprobes.txt
index 6877e71..a79633d 100644
--- a/Documentation/kprobes.txt
+++ b/Documentation/kprobes.txt
@@ -172,6 +172,7 @@ architectures:
- ia64 (Does not support probes on instruction slot1.)
- sparc64 (Return probes not yet implemented.)
- arm
+- ppc
3. Configuring Kprobes
diff --git a/arch/powerpc/kernel/kprobes.c b/arch/powerpc/kernel/kprobes.c
index 23545a2..0dca55e 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 @@ 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)
@@ -95,7 +103,14 @@ void __kprobes arch_remove_kprobe(struct kprobe *p)
static void __kprobes prepare_singlestep(struct kprobe *p, struct pt_regs
*regs)
{
+#ifdef CONFIG_BOOKE
+ regs->msr &= ~(MSR_EE); /* Turn off 'Externel Interrupt' bits */
+ regs->msr &= ~(MSR_CE); /* Turn off 'Critical Interrupt' bits */
+ regs->msr |= MSR_DE;
+ mtspr(SPRN_DBCR0, mfspr(SPRN_DBCR0) | DBCR0_IC | DBCR0_IDM);
+#else
regs->msr |= MSR_SE;
+#endif
/*
* On powerpc we should single step on the original
@@ -158,7 +173,7 @@ 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;
+ regs->msr &= ~MSR_SINGLESTEP; /* Turn off
'trace' bits */
regs->msr |= kcb->kprobe_saved_msr;
goto no_kprobe;
}
@@ -398,7 +413,7 @@ out:
* will have 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 (single_stepping(regs))
return 0;
return 1;
@@ -421,7 +436,7 @@ 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);
diff --git a/arch/powerpc/kernel/misc_32.S b/arch/powerpc/kernel/misc_32.S
index 89aaaa6..6321ae3 100644
--- a/arch/powerpc/kernel/misc_32.S
+++ b/arch/powerpc/kernel/misc_32.S
@@ -489,7 +489,7 @@ END_FTR_SECTION_IFSET(CPU_FTR_UNIFIED_ID_CACHE)
*
* flush_icache_range(unsigned long start, unsigned long stop)
*/
-_GLOBAL(__flush_icache_range)
+_KPROBE(__flush_icache_range)
BEGIN_FTR_SECTION
blr /* for 601, do nothing */
END_FTR_SECTION_IFSET(CPU_FTR_COHERENT_ICACHE)
diff --git a/arch/powerpc/kernel/traps.c b/arch/powerpc/kernel/traps.c
index 4b5b7ff..985bff5 100644
--- a/arch/powerpc/kernel/traps.c
+++ b/arch/powerpc/kernel/traps.c
@@ -316,10 +316,6 @@ static inline int check_io_access(struct pt_regs *regs)
#define REASON_PRIVILEGED ESR_PPR
#define REASON_TRAP ESR_PTR
-/* single-step stuff */
-#define single_stepping(regs) (current->thread.dbcr0 & DBCR0_IC)
-#define clear_single_step(regs) (current->thread.dbcr0 &= ~DBCR0_IC)
-
#else
/* On non-4xx, the reason for the machine check or program
exception is in the MSR. */
@@ -330,8 +326,6 @@ static inline int check_io_access(struct pt_regs *regs)
#define REASON_PRIVILEGED 0x40000
#define REASON_TRAP 0x20000
-#define single_stepping(regs) ((regs)->msr & MSR_SE)
-#define clear_single_step(regs) ((regs)->msr &= ~MSR_SE)
#endif
#if defined(CONFIG_4xx)
@@ -1030,21 +1024,29 @@ void SoftwareEmulation(struct pt_regs *regs)
#if defined(CONFIG_40x) || defined(CONFIG_BOOKE)
-void DebugException(struct pt_regs *regs, unsigned long debug_status)
+void __kprobes DebugException(struct pt_regs *regs, unsigned long debug_status)
{
if (debug_status & DBSR_IC) { /* instruction completion */
regs->msr &= ~MSR_DE;
+
+ /* Disable instruction completion */
+ mtspr(SPRN_DBCR0, mfspr(SPRN_DBCR0) & ~DBCR0_IC);
+ /* Clear the instruction completion event */
+ mtspr(SPRN_DBSR, DBSR_IC);
+
+ if (notify_die(DIE_SSTEP, "single_step", regs, 5,
+ 5, SIGTRAP) == NOTIFY_STOP) {
+ return;
+ }
+
+ if (debugger_sstep(regs))
+ return;
+
if (user_mode(regs)) {
current->thread.dbcr0 &= ~DBCR0_IC;
- } else {
- /* Disable instruction completion */
- mtspr(SPRN_DBCR0, mfspr(SPRN_DBCR0) & ~DBCR0_IC);
- /* Clear the instruction completion event */
- mtspr(SPRN_DBSR, DBSR_IC);
- if (debugger_sstep(regs))
- return;
}
- _exception(SIGTRAP, regs, TRAP_TRACE, 0);
+
+ _exception(SIGTRAP, regs, TRAP_TRACE, regs->nip);
}
}
#endif /* CONFIG_4xx || CONFIG_BOOKE */
diff --git a/include/asm-powerpc/system.h b/include/asm-powerpc/system.h
index df781ad..2926e29 100644
--- a/include/asm-powerpc/system.h
+++ b/include/asm-powerpc/system.h
@@ -66,6 +66,15 @@
struct task_struct;
struct pt_regs;
+/* single-step stuff */
+#if defined(CONFIG_4xx) || defined(CONFIG_BOOKE)
+#define single_stepping(regs) (current->thread.dbcr0 & DBCR0_IC)
+#define clear_single_step(regs) (current->thread.dbcr0 &= ~DBCR0_IC)
+#else
+#define single_stepping(regs) ((regs)->msr & MSR_SE)
+#define clear_single_step(regs) ((regs)->msr &= ~MSR_SE)
+#endif
+
#if defined(CONFIG_DEBUGGER) || defined(CONFIG_KEXEC)
extern int (*__debugger)(struct pt_regs *regs);
--
1.5.5.1
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