diff --git a/arch/ia64/kernel/process.c b/arch/ia64/kernel/process.c
index 5c9efe626563..be6c6f7be027 100644
--- a/arch/ia64/kernel/process.c
+++ b/arch/ia64/kernel/process.c
@@ -163,6 +163,8 @@ void tsk_clear_notify_resume(struct task_struct *tsk)
if (tsk->thread.pfm_needs_checking)
return;
#endif
+ if (test_ti_thread_flag(task_thread_info(tsk), TIF_RESTORE_RSE))
+ return;
clear_ti_thread_flag(task_thread_info(tsk), TIF_NOTIFY_RESUME);
}
@@ -184,6 +186,10 @@ do_notify_resume_user (sigset_t *unused, struct sigscratch *scr, long in_syscall
/* deal with pending signal delivery */
if (test_thread_flag(TIF_SIGPENDING)||test_thread_flag(TIF_RESTORE_SIGMASK))
ia64_do_signal(scr, in_syscall);
+
+ /* copy user rbs to kernel rbs */
+ if (unlikely(test_thread_flag(TIF_RESTORE_RSE)))
+ ia64_sync_krbs();
}
static int pal_halt = 1;
diff --git a/arch/ia64/kernel/ptrace.c b/arch/ia64/kernel/ptrace.c
index 2e96f17b2f3b..2de5a524a0ee 100644
--- a/arch/ia64/kernel/ptrace.c
+++ b/arch/ia64/kernel/ptrace.c
@@ -547,6 +547,72 @@ ia64_sync_user_rbs (struct task_struct *child, struct switch_stack *sw,
return 0;
}
+static long
+ia64_sync_kernel_rbs (struct task_struct *child, struct switch_stack *sw,
+ unsigned long user_rbs_start, unsigned long user_rbs_end)
+{
+ unsigned long addr, val;
+ long ret;
+
+ /* now copy word for word from user rbs to kernel rbs: */
+ for (addr = user_rbs_start; addr < user_rbs_end; addr += 8) {
+ if (access_process_vm(child, addr, &val, sizeof(val), 0)
+ != sizeof(val))
+ return -EIO;
+
+ ret = ia64_poke(child, sw, user_rbs_end, addr, val);
+ if (ret < 0)
+ return ret;
+ }
+ return 0;
+}
+
+typedef long (*syncfunc_t)(struct task_struct *, struct switch_stack *,
+ unsigned long, unsigned long);
+
+static void do_sync_rbs(struct unw_frame_info *info, void *arg)
+{
+ struct pt_regs *pt;
+ unsigned long urbs_end;
+ syncfunc_t fn = arg;
+
+ if (unw_unwind_to_user(info) < 0)
+ return;
+ pt = task_pt_regs(info->task);
+ urbs_end = ia64_get_user_rbs_end(info->task, pt, NULL);
+
+ fn(info->task, info->sw, pt->ar_bspstore, urbs_end);
+}
+
+/*
+ * when a thread is stopped (ptraced), debugger might change thread's user
+ * stack (change memory directly), and we must avoid the RSE stored in kernel
+ * to override user stack (user space's RSE is newer than kernel's in the
+ * case). To workaround the issue, we copy kernel RSE to user RSE before the
+ * task is stopped, so user RSE has updated data. we then copy user RSE to
+ * kernel after the task is resummed from traced stop and kernel will use the
+ * newer RSE to return to user. TIF_RESTORE_RSE is the flag to indicate we need
+ * synchronize user RSE to kernel.
+ */
+void ia64_ptrace_stop(void)
+{
+ if (test_and_set_tsk_thread_flag(current, TIF_RESTORE_RSE))
+ return;
+ tsk_set_notify_resume(current);
+ unw_init_running(do_sync_rbs, ia64_sync_user_rbs);
+}
+
+/*
+ * This is called to read back the register backing store.
+ */
+void ia64_sync_krbs(void)
+{
+ clear_tsk_thread_flag(current, TIF_RESTORE_RSE);
+ tsk_clear_notify_resume(current);
+
+ unw_init_running(do_sync_rbs, ia64_sync_kernel_rbs);
+}
+
static inline int
thread_matches (struct task_struct *thread, unsigned long addr)
{
@@ -1422,6 +1488,7 @@ sys_ptrace (long request, pid_t pid, unsigned long addr, unsigned long data)
struct task_struct *child;
struct switch_stack *sw;
long ret;
+ struct unw_frame_info info;
lock_kernel();
ret = -EPERM;
@@ -1453,6 +1520,8 @@ sys_ptrace (long request, pid_t pid, unsigned long addr, unsigned long data)
if (request == PTRACE_ATTACH) {
ret = ptrace_attach(child);
+ if (!ret)
+ arch_ptrace_attach(child);
goto out_tsk;
}
@@ -1481,6 +1550,11 @@ sys_ptrace (long request, pid_t pid, unsigned long addr, unsigned long data)
/* write the word at location addr */
urbs_end = ia64_get_user_rbs_end(child, pt, NULL);
ret = ia64_poke(child, sw, urbs_end, addr, data);
+
+ /* Make sure user RBS has the latest data */
+ unw_init_from_blocked_task(&info, child);
+ do_sync_rbs(&info, ia64_sync_user_rbs);
+
goto out_tsk;
case PTRACE_PEEKUSR:
@@ -1634,6 +1708,10 @@ syscall_trace_enter (long arg0, long arg1, long arg2, long arg3,
&& (current->ptrace & PT_PTRACED))
syscall_trace();
+ /* copy user rbs to kernel rbs */
+ if (test_thread_flag(TIF_RESTORE_RSE))
+ ia64_sync_krbs();
+
if (unlikely(current->audit_context)) {
long syscall;
int arch;
@@ -1671,4 +1749,8 @@ syscall_trace_leave (long arg0, long arg1, long arg2, long arg3,
|| test_thread_flag(TIF_SINGLESTEP))
&& (current->ptrace & PT_PTRACED))
syscall_trace();
+
+ /* copy user rbs to kernel rbs */
+ if (test_thread_flag(TIF_RESTORE_RSE))
+ ia64_sync_krbs();
}
diff --git a/include/asm-ia64/ptrace.h b/include/asm-ia64/ptrace.h
index f4ef87a36236..13435f778b0c 100644
--- a/include/asm-ia64/ptrace.h
+++ b/include/asm-ia64/ptrace.h
@@ -292,6 +292,7 @@ struct switch_stack {
unsigned long, long);
extern void ia64_flush_fph (struct task_struct *);
extern void ia64_sync_fph (struct task_struct *);
+ extern void ia64_sync_krbs(void);
extern long ia64_sync_user_rbs (struct task_struct *, struct switch_stack *,
unsigned long, unsigned long);
@@ -303,6 +304,12 @@ struct switch_stack {
extern void ia64_increment_ip (struct pt_regs *pt);
extern void ia64_decrement_ip (struct pt_regs *pt);
+ extern void ia64_ptrace_stop(void);
+ #define arch_ptrace_stop(code, info) \
+ ia64_ptrace_stop()
+ #define arch_ptrace_stop_needed(code, info) \
+ (!test_thread_flag(TIF_RESTORE_RSE))
+
#endif /* !__KERNEL__ */
/* pt_all_user_regs is used for PTRACE_GETREGS PTRACE_SETREGS */
diff --git a/include/asm-ia64/thread_info.h b/include/asm-ia64/thread_info.h
index 5a2c47957069..93d83cbe0c8c 100644
--- a/include/asm-ia64/thread_info.h
+++ b/include/asm-ia64/thread_info.h
@@ -94,6 +94,7 @@ extern void tsk_clear_notify_resume(struct task_struct *tsk);
#define TIF_MCA_INIT 18 /* this task is processing MCA or INIT */
#define TIF_DB_DISABLED 19 /* debug trap disabled for fsyscall */
#define TIF_FREEZE 20 /* is freezing for suspend */
+#define TIF_RESTORE_RSE 21 /* user RBS is newer than kernel RBS */
#define _TIF_SYSCALL_TRACE (1 << TIF_SYSCALL_TRACE)
#define _TIF_SYSCALL_AUDIT (1 << TIF_SYSCALL_AUDIT)
@@ -107,6 +108,7 @@ extern void tsk_clear_notify_resume(struct task_struct *tsk);
#define _TIF_MCA_INIT (1 << TIF_MCA_INIT)
#define _TIF_DB_DISABLED (1 << TIF_DB_DISABLED)
#define _TIF_FREEZE (1 << TIF_FREEZE)
+#define _TIF_RESTORE_RSE (1 << TIF_RESTORE_RSE)
/* "work to do on user-return" bits */
#define TIF_ALLWORK_MASK (_TIF_SIGPENDING|_TIF_NOTIFY_RESUME|_TIF_SYSCALL_AUDIT|\