From 0e39ac444636ff5be39b26f1cb56d79594654dda Mon Sep 17 00:00:00 2001 From: Mathieu Desnoyers Date: Fri, 6 Mar 2009 10:35:52 -0500 Subject: tracing, Text Edit Lock - Architecture Independent Code This is an architecture independant synchronization around kernel text modifications through use of a global mutex. A mutex has been chosen so that kprobes, the main user of this, can sleep during memory allocation between the memory read of the instructions it must replace and the memory write of the breakpoint. Other user of this interface: immediate values. Paravirt and alternatives are always done when SMP is inactive, so there is no need to use locks. Signed-off-by: Mathieu Desnoyers LKML-Reference: <49B142D8.7020601@redhat.com> Signed-off-by: Ingo Molnar --- include/linux/memory.h | 6 ++++++ 1 file changed, 6 insertions(+) (limited to 'include/linux/memory.h') diff --git a/include/linux/memory.h b/include/linux/memory.h index 3fdc10806d31..86a6c0f0518d 100644 --- a/include/linux/memory.h +++ b/include/linux/memory.h @@ -99,4 +99,10 @@ enum mem_add_context { BOOT, HOTPLUG }; #define hotplug_memory_notifier(fn, pri) do { } while (0) #endif +/* + * Kernel text modification mutex, used for code patching. Users of this lock + * can sleep. + */ +extern struct mutex text_mutex; + #endif /* _LINUX_MEMORY_H_ */ -- cgit v1.2.1 From 06c421ee0d5af95c8c6749ca0ba620cd5010707f Mon Sep 17 00:00:00 2001 From: Kevin Hilman Date: Thu, 2 Apr 2009 16:56:56 -0700 Subject: memory_accessor: new interface for reading/writing persistent memory Add an interface by which other kernel code can read/write persistent memory such as I2C or SPI EEPROMs, or devices which provide NVRAM. Use cases include storage of board-specific configuration data like Ethernet addresses and sensor calibrations. Original idea, review and improvement suggestions by David Brownell. Acked-by: David Brownell Signed-off-by: Kevin Hilman Cc: Jean Delvare Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/linux/memory.h | 11 +++++++++++ 1 file changed, 11 insertions(+) (limited to 'include/linux/memory.h') diff --git a/include/linux/memory.h b/include/linux/memory.h index 3fdc10806d31..42767d1a62e7 100644 --- a/include/linux/memory.h +++ b/include/linux/memory.h @@ -99,4 +99,15 @@ enum mem_add_context { BOOT, HOTPLUG }; #define hotplug_memory_notifier(fn, pri) do { } while (0) #endif +/* + * 'struct memory_accessor' is a generic interface to provide + * in-kernel access to persistent memory such as i2c or SPI EEPROMs + */ +struct memory_accessor { + ssize_t (*read)(struct memory_accessor *, char *buf, off_t offset, + size_t count); + ssize_t (*write)(struct memory_accessor *, const char *buf, + off_t offset, size_t count); +}; + #endif /* _LINUX_MEMORY_H_ */ -- cgit v1.2.1