sh: Convert ptrace to hw_breakpoint API.
This is the initial step for converting singlestep handling via ptrace
over to hw_breakpoints.
Signed-off-by: Paul Mundt <lethal@linux-sh.org>
diff --git a/arch/sh/kernel/ptrace_32.c b/arch/sh/kernel/ptrace_32.c
index bdb1044..8e094c4 100644
--- a/arch/sh/kernel/ptrace_32.c
+++ b/arch/sh/kernel/ptrace_32.c
@@ -2,7 +2,7 @@
* SuperH process tracing
*
* Copyright (C) 1999, 2000 Kaz Kojima & Niibe Yutaka
- * Copyright (C) 2002 - 2008 Paul Mundt
+ * Copyright (C) 2002 - 2009 Paul Mundt
*
* Audit support by Yuichi Nakamura <ynakam@hitachisoft.jp>
*
@@ -26,6 +26,7 @@
#include <linux/tracehook.h>
#include <linux/elf.h>
#include <linux/regset.h>
+#include <linux/hw_breakpoint.h>
#include <asm/uaccess.h>
#include <asm/pgtable.h>
#include <asm/system.h>
@@ -63,9 +64,59 @@
return 0;
}
+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.
+ */
+ attr = bp->attr;
+ attr.disabled = true;
+ modify_user_hw_breakpoint(bp, &attr);
+}
+
+static int set_single_step(struct task_struct *tsk, unsigned long addr)
+{
+ struct thread_struct *thread = &tsk->thread;
+ struct perf_event *bp;
+ struct perf_event_attr attr;
+
+ bp = thread->ptrace_bps[0];
+ if (!bp) {
+ hw_breakpoint_init(&attr);
+
+ attr.bp_addr = addr;
+ attr.bp_len = HW_BREAKPOINT_LEN_2;
+ attr.bp_type = HW_BREAKPOINT_R;
+
+ bp = register_user_hw_breakpoint(&attr, ptrace_triggered, tsk);
+ if (IS_ERR(bp))
+ return PTR_ERR(bp);
+
+ thread->ptrace_bps[0] = bp;
+ } else {
+ int err;
+
+ attr = bp->attr;
+ attr.bp_addr = addr;
+ err = modify_user_hw_breakpoint(bp, &attr);
+ if (unlikely(err))
+ return err;
+ }
+
+ return 0;
+}
+
void user_enable_single_step(struct task_struct *child)
{
+ unsigned long pc = get_stack_long(child, offsetof(struct pt_regs, pc));
+
set_tsk_thread_flag(child, TIF_SINGLESTEP);
+
+ set_single_step(child, pc);
}
void user_disable_single_step(struct task_struct *child)