x86: mmiotrace, preview 2

Kconfig.debug, Makefile and testmmiotrace.c style fixes.
Use real mutex instead of mutex.
Fix failure path in register probe func.
kmmio: RCU read-locked over single stepping.
Generate mapping id's.
Make mmio-mod.c built-in and rewrite its locking.
Add debugfs file to enable/disable mmiotracing.
kmmio: use irqsave spinlocks.
Lots of cleanups in mmio-mod.c
Marker file moved from /proc into debugfs.
Call mmiotrace entrypoints directly from ioremap.c.

Signed-off-by: Pekka Paalanen <pq@iki.fi>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

1 files changed, 8 insertions, 12 deletions

diff --git a/arch/x86/Kconfig.debug b/arch/x86/Kconfig.debug
index 9491c0ae03a..aa0d6462b1f 100644
--- a/arch/x86/Kconfig.debug
+++ b/arch/x86/Kconfig.debug
@@ -170,22 +170,19 @@ config IOMMU_LEAK
 
 config MMIOTRACE_HOOKS
         bool
-        default n
 
 config MMIOTRACE
-        tristate "Memory mapped IO tracing"
+        bool "Memory mapped IO tracing"
         depends on DEBUG_KERNEL && RELAY && DEBUG_FS
         select MMIOTRACE_HOOKS
-        default n
+        default y
         help
-          This will build a kernel module called mmiotrace.
-          Making this a built-in is heavily discouraged.
-
-          Mmiotrace traces Memory Mapped I/O access and is meant for debugging
-          and reverse engineering. The kernel module offers wrapped
-          versions of the ioremap family of functions. The driver to be traced
-          must be modified to call these wrappers. A user space program is
-          required to collect the MMIO data.
+          Mmiotrace traces Memory Mapped I/O access and is meant for
+          debugging and reverse engineering. It is called from the ioremap
+          implementation and works via page faults. A user space program is
+          required to collect the MMIO data from debugfs files.
+          Tracing is disabled by default and can be enabled from a debugfs
+          file.
 
           See http://nouveau.freedesktop.org/wiki/MmioTrace
           If you are not helping to develop drivers, say N.
@@ -193,7 +190,6 @@ config MMIOTRACE
 config MMIOTRACE_TEST
         tristate "Test module for mmiotrace"
         depends on MMIOTRACE && m
-        default n
         help
           This is a dumb module for testing mmiotrace. It is very dangerous
           as it will write garbage to IO memory starting at a given address.