Renamed file.

2005-07-14 15:27:40 +00:00
parent 312c004519
commit 2c730e8a8c
1 changed files with 33 additions and 0 deletions
--- a/kernel/utility.c
+++ b/kernel/utility.c
@@ -0,0 +1,115 @@
+/* This file contains a collection of miscellaneous procedures:
+ *   panic	    abort MINIX due to a fatal error
+ *   safe_lock	    lock the kernel, use in combination with safe_unlock
+ *   safe_unlock    unlock the kernel, but prevent breaking nested locks
+ *   alloc_bit      bit map manipulation
+ *   free_bit       bit map manipulation
+ */
+
+#include "kernel.h"
+#include "assert.h"
+#include <unistd.h>
+#include <minix/com.h>
+
+
+PRIVATE int relock_count = 0;
+
+/*===========================================================================*
+ *                                   safe_lock                               *
+ *===========================================================================*/
+PUBLIC void safe_lock(c,v)
+int c;
+char *v;
+{
+  if(!(read_cpu_flags() & X86_FLAG_I)) {
+  	relock_count++;
+  } else {
+  	intr_disable();
+  }
+}
+
+/*===========================================================================*
+ *                                   safe_unlock                             *
+ *===========================================================================*/
+PUBLIC void safe_unlock(void)
+{
+  if(! relock_count) {
+  	intr_enable();
+  } else {
+  	relock_count--;
+  }
+}
+
+/*===========================================================================*
+ *                                   panic                                   *
+ *===========================================================================*/
+PUBLIC void panic(s,n)
+_CONST char *s;
+int n;
+{
+/* The system has run aground of a fatal kernel error. Terminate execution. */
+  static int panicking = 0;
+  if (panicking ++)		/* prevent recursive panics */
+  	return;
+
+  if (s != NULL) {
+	kprintf("\nKernel panic: %s", karg(s));
+	if (n != NO_NUM) kprintf(" %d", n);
+	kprintf("\n",NO_NUM);
+  }
+  prepare_shutdown(RBT_PANIC);
+}
+
+
+
+
+/*===========================================================================*
+ *			   	free_bit				     * 
+ *===========================================================================*/
+PUBLIC void free_bit(bit_nr, bitmap, nr_bits) 
+bit_t bit_nr;
+bitchunk_t *bitmap;
+bit_t nr_bits;
+{
+  bitchunk_t *chunk;
+  if (bit_nr >= nr_bits) {
+  	kprintf("Warning, free_bit: %d illegal index\n", bit_nr);
+  	return;
+  }
+  chunk = &bitmap[(bit_nr/BITCHUNK_BITS)];
+  *chunk &= ~(1 << (bit_nr % BITCHUNK_BITS));
+}
+
+/*===========================================================================*
+ *			   	alloc_bit				     * 
+ *===========================================================================*/
+PUBLIC int alloc_bit(bitmap, nr_bits) 
+bitchunk_t *bitmap;
+bit_t nr_bits;
+{
+    bitchunk_t *chunk;
+    int nr_chunks;
+    int bit_nr;
+    int i;
+    
+    /* Iterate over the words in block. */
+    nr_chunks = BITMAP_CHUNKS(nr_bits);
+    for (chunk = &bitmap[0]; chunk < &bitmap[nr_chunks]; chunk++) {
+
+        /* Does this chunk contain a free bit? */
+        if (*chunk == (bitchunk_t) ~0) continue;
+        
+        /* Get bit number from the start of the bit map. */
+        for (i = 0; (*chunk & (1 << i)) != 0; ++i) {}
+        bit_nr = (chunk - &bitmap[0]) * BITCHUNK_BITS + i;
+        
+        /* Don't allocate bits beyond the end of the map. */
+        if (bit_nr >= nr_bits) break;
+
+        *chunk |= 1 << bit_nr % BITCHUNK_BITS;
+        return(bit_nr);        
+        
+    }
+    return(-1);    
+}
+