ptrace: simplify PTRACE_foo constants and PTRACE_SETOPTIONS code

Exchange PT_TRACESYSGOOD and PT_PTRACE_CAP bit positions, which makes
PT_option bits contiguous and therefore makes code in
ptrace_setoptions() much simpler.

Every PTRACE_O_TRACEevent is defined to (1 << PTRACE_EVENT_event)
instead of using explicit numeric constants, to ensure we don't mess up
relationship between bit positions and event ids.

PT_EVENT_FLAG_SHIFT was not particularly useful, PT_OPT_FLAG_SHIFT with
value of PT_EVENT_FLAG_SHIFT-1 is easier to use.

PT_TRACE_MASK constant is nuked, the only its use is replaced by
(PTRACE_O_MASK << PT_OPT_FLAG_SHIFT).

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
Acked-by: Tejun Heo <tj@kernel.org>
Reviewed-by: Oleg Nesterov <oleg@redhat.com>
Cc: Pedro Alves <palves@redhat.com>
Cc: Jan Kratochvil <jan.kratochvil@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 15 insertions, 18 deletions

diff --git a/include/linux/ptrace.h b/include/linux/ptrace.h
index 6fdb196caa3e..6f1260ee5be5 100644
--- a/include/linux/ptrace.h
+++ b/include/linux/ptrace.h
@@ -54,17 +54,6 @@
 /* flags in @data for PTRACE_SEIZE */
 #define PTRACE_SEIZE_DEVEL      0x80000000 /* temp flag for development */
 
-/* options set using PTRACE_SETOPTIONS */
-#define PTRACE_O_TRACESYSGOOD   0x00000001
-#define PTRACE_O_TRACEFORK      0x00000002
-#define PTRACE_O_TRACEVFORK     0x00000004
-#define PTRACE_O_TRACECLONE     0x00000008
-#define PTRACE_O_TRACEEXEC      0x00000010
-#define PTRACE_O_TRACEVFORKDONE 0x00000020
-#define PTRACE_O_TRACEEXIT      0x00000040
-
-#define PTRACE_O_MASK           0x0000007f
-
 /* Wait extended result codes for the above trace options.  */
 #define PTRACE_EVENT_FORK       1
 #define PTRACE_EVENT_VFORK      2
@@ -74,6 +63,17 @@
 #define PTRACE_EVENT_EXIT       6
 #define PTRACE_EVENT_STOP       7
 
+/* options set using PTRACE_SETOPTIONS */
+#define PTRACE_O_TRACESYSGOOD   1
+#define PTRACE_O_TRACEFORK      (1 << PTRACE_EVENT_FORK)
+#define PTRACE_O_TRACEVFORK     (1 << PTRACE_EVENT_VFORK)
+#define PTRACE_O_TRACECLONE     (1 << PTRACE_EVENT_CLONE)
+#define PTRACE_O_TRACEEXEC      (1 << PTRACE_EVENT_EXEC)
+#define PTRACE_O_TRACEVFORKDONE (1 << PTRACE_EVENT_VFORK_DONE)
+#define PTRACE_O_TRACEEXIT      (1 << PTRACE_EVENT_EXIT)
+
+#define PTRACE_O_MASK           0x0000007f
+
 #include <asm/ptrace.h>
 
 #ifdef __KERNEL__
@@ -88,13 +88,12 @@
 #define PT_SEIZED       0x00010000      /* SEIZE used, enable new behavior */
 #define PT_PTRACED      0x00000001
 #define PT_DTRACE       0x00000002      /* delayed trace (used on m68k, i386) */
-#define PT_TRACESYSGOOD 0x00000004
-#define PT_PTRACE_CAP   0x00000008      /* ptracer can follow suid-exec */
+#define PT_PTRACE_CAP   0x00000004      /* ptracer can follow suid-exec */
 
+#define PT_OPT_FLAG_SHIFT       3
 /* PT_TRACE_* event enable flags */
-#define PT_EVENT_FLAG_SHIFT     4
-#define PT_EVENT_FLAG(event)    (1 << (PT_EVENT_FLAG_SHIFT + (event) - 1))
-
+#define PT_EVENT_FLAG(event)    (1 << (PT_OPT_FLAG_SHIFT + (event)))
+#define PT_TRACESYSGOOD         PT_EVENT_FLAG(0)
 #define PT_TRACE_FORK           PT_EVENT_FLAG(PTRACE_EVENT_FORK)
 #define PT_TRACE_VFORK          PT_EVENT_FLAG(PTRACE_EVENT_VFORK)
 #define PT_TRACE_CLONE          PT_EVENT_FLAG(PTRACE_EVENT_CLONE)
@@ -102,8 +101,6 @@
 #define PT_TRACE_VFORK_DONE     PT_EVENT_FLAG(PTRACE_EVENT_VFORK_DONE)
 #define PT_TRACE_EXIT           PT_EVENT_FLAG(PTRACE_EVENT_EXIT)
 
-#define PT_TRACE_MASK   0x000003f4
-
 /* single stepping state bits (used on ARM and PA-RISC) */
 #define PT_SINGLESTEP_BIT       31
 #define PT_SINGLESTEP           (1<<PT_SINGLESTEP_BIT)