This series adds a configuration option to selectively compile out
printk message strings based on a verbosity level.
This works by wrapping printk with a macro which evaluates to a
constant if condition which the compiler will be able to optimize
out.
For situation were this filtering mechanism is not desired an
unfiltered variant is introduced: printk_unfiltered.
Currently the unfiltered variant is only used within
drivers/char/mem.c because we don't want to filter user space
data which comes is sent to /dev/kmsg.
Are there other places where the unfiltered variant should be used?
A known problem is that KERN_CONT messages aren't handled correctly.
The series was compile tested with make allyesconfig for x86 and
arm (with a cross compiler) but I might have missed something.
Thanks to Mike Frysinger and Jamie Lokier for their suggestions for
improvement.
All kinds of comments are welcome.
Marc Andre Tanner (5):
printk: introduce CONFIG_PRINTK_VERBOSITY
printk: move printk to the end of the file
printk: introduce printk_unfiltered as an alias to printk
char/mem: replace printk with printk_unfiltered
printk: provide a filtering macro for printk
drivers/char/mem.c | 2 +-
include/linux/kernel.h | 28 ++++++++++++++
init/Kconfig | 28 ++++++++++++++
kernel/printk.c | 95 ++++++++++++++++++++++++++++++------------------
4 files changed, 117 insertions(+), 36 deletions(-)
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