MIPS: Ptrace support for HARDWARE_WATCHPOINTS
This is the final part of the watch register patch. Here we hook up
ptrace so that the user space debugger (gdb), can set and read the
registers.
Signed-off-by: David Daney <ddaney@avtrex.com>
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
diff --git a/arch/mips/kernel/ptrace.c b/arch/mips/kernel/ptrace.c
index 96ffc9c..054861c 100644
--- a/arch/mips/kernel/ptrace.c
+++ b/arch/mips/kernel/ptrace.c
@@ -46,7 +46,8 @@
*/
void ptrace_disable(struct task_struct *child)
{
- /* Nothing to do.. */
+ /* Don't load the watchpoint registers for the ex-child. */
+ clear_tsk_thread_flag(child, TIF_LOAD_WATCH);
}
/*
@@ -167,6 +168,93 @@
return 0;
}
+int ptrace_get_watch_regs(struct task_struct *child,
+ struct pt_watch_regs __user *addr)
+{
+ enum pt_watch_style style;
+ int i;
+
+ if (!cpu_has_watch || current_cpu_data.watch_reg_use_cnt == 0)
+ return -EIO;
+ if (!access_ok(VERIFY_WRITE, addr, sizeof(struct pt_watch_regs)))
+ return -EIO;
+
+#ifdef CONFIG_32BIT
+ style = pt_watch_style_mips32;
+#define WATCH_STYLE mips32
+#else
+ style = pt_watch_style_mips64;
+#define WATCH_STYLE mips64
+#endif
+
+ __put_user(style, &addr->style);
+ __put_user(current_cpu_data.watch_reg_use_cnt,
+ &addr->WATCH_STYLE.num_valid);
+ for (i = 0; i < current_cpu_data.watch_reg_use_cnt; i++) {
+ __put_user(child->thread.watch.mips3264.watchlo[i],
+ &addr->WATCH_STYLE.watchlo[i]);
+ __put_user(child->thread.watch.mips3264.watchhi[i] & 0xfff,
+ &addr->WATCH_STYLE.watchhi[i]);
+ __put_user(current_cpu_data.watch_reg_masks[i],
+ &addr->WATCH_STYLE.watch_masks[i]);
+ }
+ for (; i < 8; i++) {
+ __put_user(0, &addr->WATCH_STYLE.watchlo[i]);
+ __put_user(0, &addr->WATCH_STYLE.watchhi[i]);
+ __put_user(0, &addr->WATCH_STYLE.watch_masks[i]);
+ }
+
+ return 0;
+}
+
+int ptrace_set_watch_regs(struct task_struct *child,
+ struct pt_watch_regs __user *addr)
+{
+ int i;
+ int watch_active = 0;
+ unsigned long lt[NUM_WATCH_REGS];
+ u16 ht[NUM_WATCH_REGS];
+
+ if (!cpu_has_watch || current_cpu_data.watch_reg_use_cnt == 0)
+ return -EIO;
+ if (!access_ok(VERIFY_READ, addr, sizeof(struct pt_watch_regs)))
+ return -EIO;
+ /* Check the values. */
+ for (i = 0; i < current_cpu_data.watch_reg_use_cnt; i++) {
+ __get_user(lt[i], &addr->WATCH_STYLE.watchlo[i]);
+#ifdef CONFIG_32BIT
+ if (lt[i] & __UA_LIMIT)
+ return -EINVAL;
+#else
+ if (test_tsk_thread_flag(child, TIF_32BIT_ADDR)) {
+ if (lt[i] & 0xffffffff80000000UL)
+ return -EINVAL;
+ } else {
+ if (lt[i] & __UA_LIMIT)
+ return -EINVAL;
+ }
+#endif
+ __get_user(ht[i], &addr->WATCH_STYLE.watchhi[i]);
+ if (ht[i] & ~0xff8)
+ return -EINVAL;
+ }
+ /* Install them. */
+ for (i = 0; i < current_cpu_data.watch_reg_use_cnt; i++) {
+ if (lt[i] & 7)
+ watch_active = 1;
+ child->thread.watch.mips3264.watchlo[i] = lt[i];
+ /* Set the G bit. */
+ child->thread.watch.mips3264.watchhi[i] = ht[i];
+ }
+
+ if (watch_active)
+ set_tsk_thread_flag(child, TIF_LOAD_WATCH);
+ else
+ clear_tsk_thread_flag(child, TIF_LOAD_WATCH);
+
+ return 0;
+}
+
long arch_ptrace(struct task_struct *child, long request, long addr, long data)
{
int ret;
@@ -440,6 +528,16 @@
(unsigned long __user *) data);
break;
+ case PTRACE_GET_WATCH_REGS:
+ ret = ptrace_get_watch_regs(child,
+ (struct pt_watch_regs __user *) addr);
+ break;
+
+ case PTRACE_SET_WATCH_REGS:
+ ret = ptrace_set_watch_regs(child,
+ (struct pt_watch_regs __user *) addr);
+ break;
+
default:
ret = ptrace_request(child, request, addr, data);
break;