xtensa: 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.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Roland McGrath <roland@redhat.com>
Cc: Chris Zankel <chris@zankel.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

2 files changed, 12 insertions, 45 deletions

diff --git a/arch/xtensa/include/asm/ptrace.h b/arch/xtensa/include/asm/ptrace.h
index 905e1e61965..3c549f79872 100644
--- a/arch/xtensa/include/asm/ptrace.h
+++ b/arch/xtensa/include/asm/ptrace.h
@@ -113,6 +113,7 @@ struct pt_regs {
 
 #include <variant/core.h>
 
+# define arch_has_single_step() (1)
 # define task_pt_regs(tsk) ((struct pt_regs*) \
   (task_stack_page(tsk) + KERNEL_STACK_SIZE - (XCHAL_NUM_AREGS-16)*4) - 1)
 # define user_mode(regs) (((regs)->ps & 0x00000020)!=0)
diff --git a/arch/xtensa/kernel/ptrace.c b/arch/xtensa/kernel/ptrace.c
index 9486882ef0a..9d4e1ceb3f0 100644
--- a/arch/xtensa/kernel/ptrace.c
+++ b/arch/xtensa/kernel/ptrace.c
@@ -30,6 +30,17 @@
 #include <asm/elf.h>
 #include <asm/coprocessor.h>
 
+
+void user_enable_single_step(struct task_struct *child)
+{
+        child->ptrace |= PT_SINGLESTEP;
+}
+
+void user_disable_single_step(struct task_struct *child)
+{
+        child->ptrace &= ~PT_SINGLESTEP;
+}
+
 /*
  * Called by kernel/ptrace.c when detaching to disable single stepping.
  */
@@ -268,51 +279,6 @@ long arch_ptrace(struct task_struct *child, long request, long addr, long data)
                 ret = ptrace_pokeusr(child, addr, data);
                 break;
 
-        /* continue and stop at next (return from) syscall */
-
-        case PTRACE_SYSCALL:
-        case PTRACE_CONT: /* restart after signal. */
-        {
-                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;
-                /* Make sure the single step bit is not set. */
-                child->ptrace &= ~PT_SINGLESTEP;
-                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;
-                if (child->exit_state == EXIT_ZOMBIE)   /* already dead */
-                        break;
-                child->exit_code = SIGKILL;
-                child->ptrace &= ~PT_SINGLESTEP;
-                wake_up_process(child);
-                break;
-
-        case PTRACE_SINGLESTEP:
-                ret = -EIO;
-                if (!valid_signal(data))
-                        break;
-                clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
-                child->ptrace |= PT_SINGLESTEP;
-                child->exit_code = data;
-                wake_up_process(child);
-                ret = 0;
-                break;
-
         case PTRACE_GETREGS:
                 ret = ptrace_getregs(child, (void __user *) data);
                 break;