115 lines
3.2 KiB
C
Executable file
115 lines
3.2 KiB
C
Executable file
/* This file contains a collection of miscellaneous procedures:
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* panic abort MINIX due to a fatal error
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* safe_lock lock the kernel, use in combination with safe_unlock
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* safe_unlock unlock the kernel, but prevent breaking nested locks
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* alloc_bit bit map manipulation
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* free_bit bit map manipulation
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*/
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#include "kernel.h"
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#include "assert.h"
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#include <unistd.h>
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#include <minix/com.h>
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PRIVATE int relock_count = 0;
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/*===========================================================================*
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* safe_lock *
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*===========================================================================*/
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PUBLIC void safe_lock(c,v)
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int c;
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char *v;
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{
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if(!(read_cpu_flags() & X86_FLAG_I)) {
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relock_count++;
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} else {
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intr_disable();
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}
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}
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/*===========================================================================*
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* safe_unlock *
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*===========================================================================*/
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PUBLIC void safe_unlock(void)
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{
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if(! relock_count) {
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intr_enable();
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} else {
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relock_count--;
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}
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}
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/*===========================================================================*
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* panic *
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*===========================================================================*/
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PUBLIC void panic(s,n)
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_CONST char *s;
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int n;
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{
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/* The system has run aground of a fatal kernel error. Terminate execution. */
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static int panicking = 0;
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if (panicking ++) /* prevent recursive panics */
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return;
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if (s != NULL) {
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kprintf("\nKernel panic: %s", karg(s));
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if (n != NO_NUM) kprintf(" %d", n);
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kprintf("\n",NO_NUM);
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}
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prepare_shutdown(RBT_PANIC);
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}
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/*===========================================================================*
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* free_bit *
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*===========================================================================*/
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PUBLIC void free_bit(bit_nr, bitmap, nr_bits)
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bit_t bit_nr;
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bitchunk_t *bitmap;
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bit_t nr_bits;
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{
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bitchunk_t *chunk;
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if (bit_nr >= nr_bits) {
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kprintf("Warning, free_bit: %d illegal index\n", bit_nr);
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return;
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}
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chunk = &bitmap[(bit_nr/BITCHUNK_BITS)];
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*chunk &= ~(1 << (bit_nr % BITCHUNK_BITS));
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}
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/*===========================================================================*
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* alloc_bit *
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*===========================================================================*/
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PUBLIC int alloc_bit(bitmap, nr_bits)
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bitchunk_t *bitmap;
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bit_t nr_bits;
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{
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bitchunk_t *chunk;
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int nr_chunks;
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int bit_nr;
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int i;
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/* Iterate over the words in block. */
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nr_chunks = BITMAP_CHUNKS(nr_bits);
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for (chunk = &bitmap[0]; chunk < &bitmap[nr_chunks]; chunk++) {
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/* Does this chunk contain a free bit? */
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if (*chunk == (bitchunk_t) ~0) continue;
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/* Get bit number from the start of the bit map. */
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for (i = 0; (*chunk & (1 << i)) != 0; ++i) {}
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bit_nr = (chunk - &bitmap[0]) * BITCHUNK_BITS + i;
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/* Don't allocate bits beyond the end of the map. */
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if (bit_nr >= nr_bits) break;
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*chunk |= 1 << bit_nr % BITCHUNK_BITS;
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return(bit_nr);
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}
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return(-1);
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}
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