x86: PTRACE_SINGLEBLOCK

This adds the PTRACE_SINGLEBLOCK request on x86, matching the ia64 feature.
The implementation comes from the generic ptrace code and relies on the
low-level machine support provided by arch_has_block_step() et al.

Signed-off-by: Roland McGrath <roland@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

arch/x86/ia32/ptrace32.c

@@ -227,6 +227,7 @@ asmlinkage long sys32_ptrace(long request, u32 pid, u32 addr, u32 data)
 	case PTRACE_KILL:
 	case PTRACE_CONT:
 	case PTRACE_SINGLESTEP:
+	case PTRACE_SINGLEBLOCK:
 	case PTRACE_DETACH:
 	case PTRACE_SYSCALL:
 	case PTRACE_OLDSETOPTIONS:

include/asm-x86/ptrace-abi.h

@@ -78,4 +78,6 @@
 # define PTRACE_SYSEMU_SINGLESTEP 32
 #endif
 
+#define PTRACE_SINGLEBLOCK	33	/* resume execution until next branch */
+
 #endif