minix/kernel/utility.c
Tomas Hruby 0a55e63413 SMP - fixed IPI livelock
- two CPUs can issue IPI to each other now without any hazzard

- we must be able to handle synchronous scheduling IPIs from
  other CPUs when we are waiting for attention from another one.
  Otherwise we might livelock.

- necessary barriers to prevent reordering
2012-01-13 11:30:00 +00:00

92 lines
2.3 KiB
C

/* This file contains a collection of miscellaneous procedures:
* panic: abort MINIX due to a fatal error
* kputc: buffered putc used by kernel printf
*/
#include "kernel.h"
#include "proc.h"
#include <minix/syslib.h>
#include <unistd.h>
#include <stdarg.h>
#include <signal.h>
#include <minix/sys_config.h>
#define ARE_PANICING 0xDEADC0FF
/*===========================================================================*
* panic *
*===========================================================================*/
PUBLIC void panic(const char *fmt, ...)
{
va_list arg;
/* The system has run aground of a fatal kernel error. Terminate execution. */
if (minix_panicing == ARE_PANICING) {
arch_monitor();
}
minix_panicing = ARE_PANICING;
if (fmt != NULL) {
printf("kernel panic: ");
va_start(arg, fmt);
vprintf(fmt, arg);
printf("\n");
}
printf("kernel on CPU %d: ", cpuid);
util_stacktrace();
printf("current process : ");
proc_stacktrace(get_cpulocal_var(proc_ptr));
/* Abort MINIX. */
minix_shutdown(NULL);
}
/*===========================================================================*
* kputc *
*===========================================================================*/
PUBLIC void kputc(c)
int c; /* character to append */
{
/* Accumulate a single character for a kernel message. Send a notification
* to the output driver if an END_OF_KMESS is encountered.
*/
if (c != END_OF_KMESS) {
#ifdef DEBUG_SERIAL
if (do_serial_debug) {
if(c == '\n')
ser_putc('\r');
ser_putc(c);
}
#endif
kmess.km_buf[kmess.km_next] = c; /* put normal char in buffer */
if (kmess.km_size < sizeof(kmess.km_buf))
kmess.km_size += 1;
kmess.km_next = (kmess.km_next + 1) % _KMESS_BUF_SIZE;
} else {
int p;
endpoint_t outprocs[] = OUTPUT_PROCS_ARRAY;
if(!(minix_panicing || do_serial_debug)) {
for(p = 0; outprocs[p] != NONE; p++) {
if(isokprocn(outprocs[p]) && !isemptyn(outprocs[p])) {
send_sig(outprocs[p], SIGKMESS);
}
}
}
}
return;
}
PUBLIC void cpu_print_freq(unsigned cpu)
{
u64_t freq;
freq = cpu_get_freq(cpu);
printf("CPU %d freq %lu MHz\n", cpu, div64u(freq, 1000000));
}
PUBLIC int is_fpu(void)
{
return get_cpulocal_var(fpu_presence);
}