diff options
author | Thomas Meyer <thomas@m3y3r.de> | 2015-03-28 10:07:37 +0100 |
---|---|---|
committer | Richard Weinberger <richard@nod.at> | 2015-04-13 21:17:37 +0200 |
commit | 04a418495e0852263d77c4fb82adf470feaafef3 (patch) | |
tree | 55101ddcf7076f7f90a4957b3cdaed946289ccd7 /arch/um | |
parent | fc9bea0e28db8cbfe0a08c1bfb1796bfd7adf49b (diff) | |
download | linux-04a418495e0852263d77c4fb82adf470feaafef3.tar.bz2 |
um: add a kmsg_dumper
Add a kmsg_dumper, that dumps the kmsg buffer to stdout, when no console
is available. This an enables the printing of early panic() calls
triggered in uml_postsetup().
When a panic() call happens so early in the UML kernel no
earlyprintk/console is available yet, but with a kmsg_dumper in place
the kernel message buffer will be outputted to the user, to give a
better hint, of what the failure was.
Signed-off-by: Thomas Meyer <thomas@m3y3r.de>
Signed-off-by: Richard Weinberger <richard@nod.at>
Diffstat (limited to 'arch/um')
-rw-r--r-- | arch/um/kernel/Makefile | 2 | ||||
-rw-r--r-- | arch/um/kernel/kmsg_dump.c | 43 | ||||
-rw-r--r-- | arch/um/kernel/um_arch.c | 2 |
3 files changed, 46 insertions, 1 deletions
diff --git a/arch/um/kernel/Makefile b/arch/um/kernel/Makefile index b7e31e5a8c0c..a6a5e42caaef 100644 --- a/arch/um/kernel/Makefile +++ b/arch/um/kernel/Makefile @@ -13,7 +13,7 @@ clean-files := obj-y = config.o exec.o exitcode.o irq.o ksyms.o mem.o \ physmem.o process.o ptrace.o reboot.o sigio.o \ signal.o syscall.o sysrq.o time.o tlb.o trap.o \ - um_arch.o umid.o maccess.o skas/ + um_arch.o umid.o maccess.o kmsg_dump.o skas/ obj-$(CONFIG_BLK_DEV_INITRD) += initrd.o obj-$(CONFIG_GPROF) += gprof_syms.o diff --git a/arch/um/kernel/kmsg_dump.c b/arch/um/kernel/kmsg_dump.c new file mode 100644 index 000000000000..407d49251d6f --- /dev/null +++ b/arch/um/kernel/kmsg_dump.c @@ -0,0 +1,43 @@ +#include <linux/kmsg_dump.h> +#include <linux/console.h> +#include <shared/init.h> +#include <shared/kern.h> +#include <os.h> + +static void kmsg_dumper_stdout(struct kmsg_dumper *dumper, + enum kmsg_dump_reason reason) +{ + static char line[1024]; + + size_t len = 0; + bool con_available = false; + + /* only dump kmsg when no console is available */ + if (!console_trylock()) + return; + + if (console_drivers != NULL) + con_available = true; + + console_unlock(); + + if (con_available == true) + return; + + printf("kmsg_dump:\n"); + while (kmsg_dump_get_line(dumper, true, line, sizeof(line), &len)) { + line[len] = '\0'; + printf("%s", line); + } +} + +static struct kmsg_dumper kmsg_dumper = { + .dump = kmsg_dumper_stdout +}; + +int __init kmsg_dumper_stdout_init(void) +{ + return kmsg_dump_register(&kmsg_dumper); +} + +__uml_postsetup(kmsg_dumper_stdout_init); diff --git a/arch/um/kernel/um_arch.c b/arch/um/kernel/um_arch.c index 9b06957e98ce..926ecdceba86 100644 --- a/arch/um/kernel/um_arch.c +++ b/arch/um/kernel/um_arch.c @@ -11,6 +11,7 @@ #include <linux/string.h> #include <linux/utsname.h> #include <linux/sched.h> +#include <linux/kmsg_dump.h> #include <asm/pgtable.h> #include <asm/processor.h> #include <asm/sections.h> @@ -211,6 +212,7 @@ static void __init uml_postsetup(void) static int panic_exit(struct notifier_block *self, unsigned long unused1, void *unused2) { + kmsg_dump(KMSG_DUMP_PANIC); bust_spinlocks(1); bust_spinlocks(0); uml_exitcode = 1; |