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-rw-r--r--arch/powerpc/kernel/ptrace.c64
1 files changed, 64 insertions, 0 deletions
diff --git a/arch/powerpc/kernel/ptrace.c b/arch/powerpc/kernel/ptrace.c
index 7a0c0199ea28..11f3cd9c832f 100644
--- a/arch/powerpc/kernel/ptrace.c
+++ b/arch/powerpc/kernel/ptrace.c
@@ -32,6 +32,8 @@
#ifdef CONFIG_PPC32
#include <linux/module.h>
#endif
+#include <linux/hw_breakpoint.h>
+#include <linux/perf_event.h>
#include <asm/uaccess.h>
#include <asm/page.h>
@@ -866,9 +868,34 @@ void user_disable_single_step(struct task_struct *task)
clear_tsk_thread_flag(task, TIF_SINGLESTEP);
}
+#ifdef CONFIG_HAVE_HW_BREAKPOINT
+void ptrace_triggered(struct perf_event *bp, int nmi,
+ struct perf_sample_data *data, struct pt_regs *regs)
+{
+ struct perf_event_attr attr;
+
+ /*
+ * Disable the breakpoint request here since ptrace has defined a
+ * one-shot behaviour for breakpoint exceptions in PPC64.
+ * The SIGTRAP signal is generated automatically for us in do_dabr().
+ * We don't have to do anything about that here
+ */
+ attr = bp->attr;
+ attr.disabled = true;
+ modify_user_hw_breakpoint(bp, &attr);
+}
+#endif /* CONFIG_HAVE_HW_BREAKPOINT */
+
int ptrace_set_debugreg(struct task_struct *task, unsigned long addr,
unsigned long data)
{
+#ifdef CONFIG_HAVE_HW_BREAKPOINT
+ int ret;
+ struct thread_struct *thread = &(task->thread);
+ struct perf_event *bp;
+ struct perf_event_attr attr;
+#endif /* CONFIG_HAVE_HW_BREAKPOINT */
+
/* For ppc64 we support one DABR and no IABR's at the moment (ppc64).
* For embedded processors we support one DAC and no IAC's at the
* moment.
@@ -896,6 +923,43 @@ int ptrace_set_debugreg(struct task_struct *task, unsigned long addr,
/* Ensure breakpoint translation bit is set */
if (data && !(data & DABR_TRANSLATION))
return -EIO;
+#ifdef CONFIG_HAVE_HW_BREAKPOINT
+ bp = thread->ptrace_bps[0];
+ if ((!data) || !(data & (DABR_DATA_WRITE | DABR_DATA_READ))) {
+ if (bp) {
+ unregister_hw_breakpoint(bp);
+ thread->ptrace_bps[0] = NULL;
+ }
+ return 0;
+ }
+ if (bp) {
+ attr = bp->attr;
+ attr.bp_addr = data & ~HW_BREAKPOINT_ALIGN;
+ arch_bp_generic_fields(data &
+ (DABR_DATA_WRITE | DABR_DATA_READ),
+ &attr.bp_type);
+ ret = modify_user_hw_breakpoint(bp, &attr);
+ if (ret)
+ return ret;
+ thread->ptrace_bps[0] = bp;
+ thread->dabr = data;
+ return 0;
+ }
+
+ /* Create a new breakpoint request if one doesn't exist already */
+ hw_breakpoint_init(&attr);
+ attr.bp_addr = data & ~HW_BREAKPOINT_ALIGN;
+ arch_bp_generic_fields(data & (DABR_DATA_WRITE | DABR_DATA_READ),
+ &attr.bp_type);
+
+ thread->ptrace_bps[0] = bp = register_user_hw_breakpoint(&attr,
+ ptrace_triggered, task);
+ if (IS_ERR(bp)) {
+ thread->ptrace_bps[0] = NULL;
+ return PTR_ERR(bp);
+ }
+
+#endif /* CONFIG_HAVE_HW_BREAKPOINT */
/* Move contents to the DABR register */
task->thread.dabr = data;