sh: Clear UBC when not in use.

[safe/jmp/linux-2.6] / arch / sh / kernel / ptrace.c

diff --git a/arch/sh/kernel/ptrace.c b/arch/sh/kernel/ptrace.c
index 04ca13a..855f724 100644 (file)
--- a/arch/sh/kernel/ptrace.c
+++ b/arch/sh/kernel/ptrace.c
@@ -8,7 +8,6 @@
  * SuperH version:   Copyright (C) 1999, 2000  Kaz Kojima & Niibe Yutaka
  *
  */
-
 #include <linux/kernel.h>
 #include <linux/sched.h>
 #include <linux/mm.h>
@@ -20,8 +19,7 @@
 #include <linux/slab.h>
 #include <linux/security.h>
 #include <linux/signal.h>
-
-#include <asm/io.h>
+#include <linux/io.h>
 #include <asm/uaccess.h>
 #include <asm/pgtable.h>
 #include <asm/system.h>
@@ -59,6 +57,23 @@ static inline int put_stack_long(struct task_struct *task, int offset,
        return 0;
 }
 
+static void ptrace_disable_singlestep(struct task_struct *child)
+{
+       clear_tsk_thread_flag(child, TIF_SINGLESTEP);
+
+       /*
+        * Ensure the UBC is not programmed at the next context switch.
+        *
+        * Normally this is not needed but there are sequences such as
+        * singlestep, signal delivery, and continue that leave the
+        * ubc_pc non-zero leading to spurious SIGTRAPs.
+        */
+       if (child->thread.ubc_pc != 0) {
+               ubc_usercnt -= 1;
+               child->thread.ubc_pc = 0;
+       }
+}
+
 /*
  * Called by kernel/ptrace.c when detaching..
  *
@@ -66,7 +81,7 @@ static inline int put_stack_long(struct task_struct *task, int offset,
  */
 void ptrace_disable(struct task_struct *child)
 {
-       /* nothing to do.. */
+       ptrace_disable_singlestep(child);
 }
 
 long arch_ptrace(struct task_struct *child, long request, long addr, long data)
@@ -76,7 +91,7 @@ long arch_ptrace(struct task_struct *child, long request, long addr, long data)
 
        switch (request) {
        /* when I and D space are separate, these will need to be fixed. */
-       case PTRACE_PEEKTEXT: /* read word at location addr. */ 
+       case PTRACE_PEEKTEXT: /* read word at location addr. */
        case PTRACE_PEEKDATA: {
                unsigned long tmp;
                int copied;
@@ -94,7 +109,7 @@ long arch_ptrace(struct task_struct *child, long request, long addr, long data)
                unsigned long tmp;
 
                ret = -EIO;
-               if ((addr & 3) || addr < 0 || 
+               if ((addr & 3) || addr < 0 ||
                    addr > sizeof(struct user) - 3)
                        break;
 
@@ -129,7 +144,7 @@ long arch_ptrace(struct task_struct *child, long request, long addr, long data)
 
        case PTRACE_POKEUSR: /* write the word at location addr in the USER area */
                ret = -EIO;
-               if ((addr & 3) || addr < 0 || 
+               if ((addr & 3) || addr < 0 ||
                    addr > sizeof(struct user) - 3)
                        break;
 
@@ -156,6 +171,9 @@ long arch_ptrace(struct task_struct *child, long request, long addr, long data)
                        set_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
                else
                        clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
+
+               ptrace_disable_singlestep(child);
+
                child->exit_code = data;
                wake_up_process(child);
                ret = 0;
@@ -163,14 +181,15 @@ long arch_ptrace(struct task_struct *child, long request, long addr, long data)
        }
 
 /*
- * make the child exit.  Best I can do is send it a sigkill. 
- * perhaps it should be put in the status that it wants to 
+ * make the child exit.  Best I can do is send it a sigkill.
+ * perhaps it should be put in the status that it wants to
  * exit.
  */
        case PTRACE_KILL: {
                ret = 0;
                if (child->exit_state == EXIT_ZOMBIE)   /* already dead */
                        break;
+               ptrace_disable_singlestep(child);
                child->exit_code = SIGKILL;
                wake_up_process(child);
                break;
@@ -196,6 +215,7 @@ long arch_ptrace(struct task_struct *child, long request, long addr, long data)
                        ubc_usercnt += 1;
                child->thread.ubc_pc = pc;
 
+               set_tsk_thread_flag(child, TIF_SINGLESTEP);
                child->exit_code = data;
                /* give it a chance to run. */
                wake_up_process(child);
@@ -248,14 +268,15 @@ asmlinkage void do_syscall_trace(void)
 {
        struct task_struct *tsk = current;
 
-       if (!test_thread_flag(TIF_SYSCALL_TRACE))
+       if (!test_thread_flag(TIF_SYSCALL_TRACE) &&
+           !test_thread_flag(TIF_SINGLESTEP))
                return;
        if (!(tsk->ptrace & PT_PTRACED))
                return;
        /* the 0x80 provides a way for the tracing parent to distinguish
           between a syscall stop and SIGTRAP delivery */
-       ptrace_notify(SIGTRAP | ((current->ptrace & PT_TRACESYSGOOD)
-                                ? 0x80 : 0));
+       ptrace_notify(SIGTRAP | ((current->ptrace & PT_TRACESYSGOOD) &&
+                                !test_thread_flag(TIF_SINGLESTEP) ? 0x80 : 0));
 
        /*
         * this isn't the same as continuing with a signal, but it will do