3rd-party/linux-kernel-module-cheat
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Code Issues Releases Wiki Activity

init_dev_kmsg

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Ciro Santilli
2017-10-01 22:21:14 +01:00
parent 71d673bac4
commit 88cd83cd02
3 changed files with 15 additions and 1 deletions
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1
kernel_module/user/README.md
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@@ -16,6 +16,7 @@ These programs can also be compiled and used on host.
1. inits 1. inits
1. [sleep_forever](sleep_forever.c) 1. [sleep_forever](sleep_forever.c)
1. [poweroff](poweroff.c) 1. [poweroff](poweroff.c)
1. [init_dev_kmsg](init_dev_kmsg.c)
1. [uio_read](uio_read.c) 1. [uio_read](uio_read.c)
1. Module tests 1. Module tests
1. [anonymous_inode](anonymous_inode.c) 1. [anonymous_inode](anonymous_inode.c)

13
kernel_module/user/init_dev_kmsg.c Normal file
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@@ -0,0 +1,13 @@
/* https://stackoverflow.com/questions/12683169/measure-time-taken-for-linux-kernel-from-bootup-to-userpace/46517014#46517014 */
#include <stdio.h>
#include <unistd.h>
int main(void) {
FILE *fp;
fp = fopen("/dev/kmsg", "w");
fputs(__FILE__ "\n", fp);
fclose(fp);
while (1)
sleep(0xFFFFFFFF);
}

2
runqemu
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@@ -10,7 +10,7 @@ kgdb=false
nographic=false nographic=false
# norandmaps: Don't use address space randomization. Equivalent to echo 0 > /proc/sys/kernel/randomize_va_space. # norandmaps: Don't use address space randomization. Equivalent to echo 0 > /proc/sys/kernel/randomize_va_space.
# printk.time=y: log in format: "[time ] msg" for all printk messages. # printk.time=y: log in format: "[time ] msg" for all printk messages.
extra_append='norandmaps printk.time=y' extra_append='norandmaps printk.devkmsg=on printk.time=y'
extra_flags='' extra_flags=''
while getopts a:de:knqt: OPT; do while getopts a:de:knqt: OPT; do
case "$OPT" in case "$OPT" in