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authorPekka Paalanen <pq@iki.fi>2008-05-12 21:20:56 +0200
committerThomas Gleixner <tglx@linutronix.de>2008-05-24 11:21:14 +0200
commit8b7d89d02ef3c6a7c73d6596f28cea7632850af4 (patch)
tree32601bf4f34dd9e3ec1e9610c555e10dc448006c /arch/x86/Kconfig.debug
parent677aa9f77e8de3791b481a0cec6c8b84d1eec626 (diff)
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x86: mmiotrace - trace memory mapped IO
Mmiotrace is a tool for trapping memory mapped IO (MMIO) accesses within the kernel. It is used for debugging and especially for reverse engineering evil binary drivers. Mmiotrace works by wrapping the ioremap family of kernel functions and marking the returned pages as not present. Access to the IO memory triggers a page fault, which will be handled by mmiotrace's custom page fault handler. This will single-step the faulted instruction with the MMIO page marked as present. Access logs are directed to user space via relay and debug_fs. This page fault approach is necessary, because binary drivers have readl/writel etc. calls inlined and therefore extremely difficult to trap with with e.g. kprobes. This patch depends on the custom page fault handlers patch. Signed-off-by: Pekka Paalanen <pq@iki.fi> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Diffstat (limited to 'arch/x86/Kconfig.debug')
-rw-r--r--arch/x86/Kconfig.debug27
1 files changed, 27 insertions, 0 deletions
diff --git a/arch/x86/Kconfig.debug b/arch/x86/Kconfig.debug
index 9431a8399844..7c6496e2225e 100644
--- a/arch/x86/Kconfig.debug
+++ b/arch/x86/Kconfig.debug
@@ -176,6 +176,33 @@ config PAGE_FAULT_HANDLERS
register a function that is called on every page fault. Custom
handlers are used by some debugging and reverse engineering tools.
+config MMIOTRACE
+ tristate "Memory mapped IO tracing"
+ depends on DEBUG_KERNEL && PAGE_FAULT_HANDLERS && RELAY && DEBUG_FS
+ default n
+ help
+ This will build a kernel module called mmiotrace.
+
+ 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.
+
+ See http://nouveau.freedesktop.org/wiki/MmioTrace
+ If you are not helping to develop drivers, say N.
+
+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.
+ However, it should be safe to use on e.g. unused portion of VRAM.
+
+ Say N, unless you absolutely know what you are doing.
+
#
# IO delay types:
#