833c95456a
Many devices run firmware and/or complex hardware, and most of that
can have bugs. When it misbehaves, however, it is often much harder
to debug than software running on the host.
Introduce a "device coredump" mechanism to allow dumping internal
device/firmware state through a generalized mechanism. As devices
are different and information needed can vary accordingly, this
doesn't prescribe a file format - it just provides mechanism to
get data to be able to capture it in a generalized way (e.g. in
distributions.)
The dumped data will be readable in sysfs in the virtual device's
data file under /sys/class/devcoredump/devcd*/. Writing to it will
free the data and remove the device, as does a 5-minute timeout.
Note that generalized capturing of such data may result in privacy
issues, so users generally need to be involved. In order to allow
certain users/system integrators/... to disable the feature at all,
introduce a Kconfig option to override the drivers that would like
to have the feature.
For now, this provides two ways of dumping data:
1) with a vmalloc'ed area, that is then given to the subsystem
and freed after retrieval or timeout
2) with a generalized reader/free function method
We could/should add more options, e.g. a list of pages, since the
vmalloc area is very limited on some architectures.
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
35 lines
986 B
C
35 lines
986 B
C
#ifndef __DEVCOREDUMP_H
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#define __DEVCOREDUMP_H
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#include <linux/device.h>
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#include <linux/module.h>
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#include <linux/vmalloc.h>
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#ifdef CONFIG_DEV_COREDUMP
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void dev_coredumpv(struct device *dev, const void *data, size_t datalen,
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gfp_t gfp);
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void dev_coredumpm(struct device *dev, struct module *owner,
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const void *data, size_t datalen, gfp_t gfp,
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ssize_t (*read)(char *buffer, loff_t offset, size_t count,
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const void *data, size_t datalen),
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void (*free)(const void *data));
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#else
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static inline void dev_coredumpv(struct device *dev, const void *data,
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size_t datalen, gfp_t gfp)
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{
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vfree(data);
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}
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static inline void
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dev_coredumpm(struct device *dev, struct module *owner,
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const void *data, size_t datalen, gfp_t gfp,
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ssize_t (*read)(char *buffer, loff_t offset, size_t count,
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const void *data, size_t datalen),
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void (*free)(const void *data))
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{
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free(data);
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}
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#endif /* CONFIG_DEV_COREDUMP */
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#endif /* __DEVCOREDUMP_H */
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