m32r: use generic ptrace_resume code

Use the generic ptrace_resume code for PTRACE_SYSCALL, PTRACE_CONT,
PTRACE_KILL and PTRACE_SINGLESTEP.  This implies defining
arch_has_single_step in <asm/ptrace.h> and implementing the
user_enable_single_step and user_disable_single_step functions, which also
causes the breakpoint information to be cleared on fork, which could be
considered a bug fix.

Also the TIF_SYSCALL_TRACE thread flag is now cleared on PTRACE_KILL which
it previously wasn't, which is consistent with all architectures using the
modern ptrace code.

The old code only disables the breakpoints on PTRACE_KILL, while after
this patch this also happens for PTRACE_CONT and PTRACE_SYSCALL which
matches the behaviour of the other architetures.  I think this is a
bugfixes, but please double verify this is correct.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Roland McGrath <roland@redhat.com>
Cc: Hirokazu Takata <takata@linux-m32r.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/arch/m32r/include/asm/ptrace.h b/arch/m32r/include/asm/ptrace.h
index a0755b9..840a123 100644 (file)
--- a/arch/m32r/include/asm/ptrace.h
+++ b/arch/m32r/include/asm/ptrace.h
@@ -120,6 +120,8 @@ struct pt_regs {
 
 #include <asm/m32r.h>          /* M32R_PSW_BSM, M32R_PSW_BPM */
 
+#define arch_has_single_step() (1)
+
 struct task_struct;
 extern void init_debug_traps(struct task_struct *);
 #define arch_ptrace_attach(child) \

diff --git a/arch/m32r/kernel/ptrace.c b/arch/m32r/kernel/ptrace.c
index 98682bb..e555091 100644 (file)
--- a/arch/m32r/kernel/ptrace.c
+++ b/arch/m32r/kernel/ptrace.c
@@ -580,6 +580,35 @@ init_debug_traps(struct task_struct *child)
        }
 }
 
+void user_enable_single_step(struct task_struct *child)
+{
+       unsigned long next_pc;
+       unsigned long pc, insn;
+
+       clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
+
+       /* Compute next pc.  */
+       pc = get_stack_long(child, PT_BPC);
+
+       if (access_process_vm(child, pc&~3, &insn, sizeof(insn), 0)
+           != sizeof(insn))
+               break;
+
+       compute_next_pc(insn, pc, &next_pc, child);
+       if (next_pc & 0x80000000)
+               break;
+
+       if (embed_debug_trap(child, next_pc))
+               break;
+
+       invalidate_cache();
+}
+
+void user_disable_single_step(struct task_struct *child)
+{
+       unregister_all_debug_traps(child);
+       invalidate_cache();
+}
 
 /*
  * Called by kernel/ptrace.c when detaching..
@@ -630,74 +659,6 @@ arch_ptrace(struct task_struct *child, long request, long addr, long data)
                ret = ptrace_write_user(child, addr, data);
                break;
 
-       /*
-        * continue/restart and stop at next (return from) syscall
-        */
-       case PTRACE_SYSCALL:
-       case PTRACE_CONT:
-               ret = -EIO;
-               if (!valid_signal(data))
-                       break;
-               if (request == PTRACE_SYSCALL)
-                       set_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
-               else
-                       clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
-               child->exit_code = data;
-               wake_up_process(child);
-               ret = 0;
-               break;
-
-       /*
-        * 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;
-               unregister_all_debug_traps(child);
-               invalidate_cache();
-               if (child->exit_state == EXIT_ZOMBIE)   /* already dead */
-                       break;
-               child->exit_code = SIGKILL;
-               wake_up_process(child);
-               break;
-       }
-
-       /*
-        * execute single instruction.
-        */
-       case PTRACE_SINGLESTEP: {
-               unsigned long next_pc;
-               unsigned long pc, insn;
-
-               ret = -EIO;
-               if (!valid_signal(data))
-                       break;
-               clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
-
-               /* Compute next pc.  */
-               pc = get_stack_long(child, PT_BPC);
-
-               if (access_process_vm(child, pc&~3, &insn, sizeof(insn), 0)
-                   != sizeof(insn))
-                       break;
-
-               compute_next_pc(insn, pc, &next_pc, child);
-               if (next_pc & 0x80000000)
-                       break;
-
-               if (embed_debug_trap(child, next_pc))
-                       break;
-
-               invalidate_cache();
-               child->exit_code = data;
-
-               /* give it a chance to run. */
-               wake_up_process(child);
-               ret = 0;
-               break;
-       }
-
        case PTRACE_GETREGS:
                ret = ptrace_getregs(child, (void __user *)data);
                break;