PMM and liballoc port

kernel/libk/align.h

@@ -0,0 +1,8 @@
+#ifndef _KERNEL_LIBK_ALIGN_H
+#define _KERNEL_LIBK_ALIGN_H
+
+#define div_align_up(x, div) (((x) + (div) - 1) / (div))
+#define align_down(x, a)  ((x) & ~((a) - 1))
+#define align_up(x, a)  (((x) + ((a) - 1)) & ~((a) - 1))
+
+#endif // _KERNEL_LIBK_ALIGN_H

kernel/libk/bm.c

@@ -0,0 +1,91 @@
+#include <libk/std.h>
+#include <libk/bm.h>
+#include <libk/string.h>
+
+void bm_init(struct bm *bm, uint8_t *base, size_t nbits) {
+  bm->base = base;
+  bm->nbits = nbits;
+  memset(bm->base, 0, (nbits + 7) / 8);
+}
+
+/*
+ * Set a bit in a bitmap.
+ */
+void bm_set(struct bm *bm, size_t k) {
+  if (k >= bm->nbits)
+    return;
+
+  uint8_t *b = (uint8_t *)((uintptr_t)bm->base + (k / 8));
+  *b = ((*b) | (1 << (k % 8)));
+}
+
+/*
+ * Clear a bit in a bitmap.
+ */
+void bm_clear(struct bm *bm, size_t k) {
+  if (k >= bm->nbits)
+    return;
+
+  uint8_t *b = (uint8_t *)((uintptr_t)bm->base + (k / 8));
+  *b = ((*b) & ~(1 << (k % 8)));
+}
+
+/*
+ * Test (true/false) a bit in a bitmap.
+ */
+bool bm_test(struct bm *bm, size_t k) {
+  if (k >= bm->nbits)
+    return false;
+
+  uint8_t *b = (uint8_t *)((uintptr_t)bm->base + (k / 8));
+  return (*b) & (1 << (k % 8));
+}
+
+/*
+ * Set a range of bits in a bitmap. if starting bit is out of range, we fail.
+ */
+bool bm_set_region(struct bm *bm, size_t k, size_t m) {
+  if ((k >= m) || (k >= bm->nbits) || (k + m >= bm->nbits))
+    return false;
+
+  for (size_t i = k; i < m; i++) {
+    bool taken = bm_test(bm, i);
+    if (taken)
+      return false;
+  }
+
+  for (size_t i = k; i < m; i++)
+    bm_set(bm, i);
+  
+  return true;
+}
+
+/*
+ * Clear a range of bits in a bitmap. starting bit must be in range.
+ */
+void bm_clear_region(struct bm *bm, size_t k, size_t m) {
+  if ((k >= m) || (k >= bm->nbits) || (k + m >= bm->nbits))
+    return;
+
+  for (size_t i = k; i < m; i++)
+    bm_clear(bm, i);
+}
+
+/*
+ * Test a range if bits in a bitmap. Return true if at least one bit
+ * is set, else return false (all bits clear). For convenience, if k or m
+ * are out of range, act as if the bits are set / bitmap is full - this is
+ * useful for implementing the physical memory manager algorithm.
+ */
+bool bm_test_region(struct bm *bm, size_t k, size_t m) {
+  if ((k >= m) || (k >= bm->nbits) || (k + m >= bm->nbits))
+    return true;
+
+  for (size_t i = k; i < m; i++) {
+    bool test = bm_test(bm, i);
+    if (test)
+      return true;
+  }
+
+  return false;
+}

kernel/libk/bm.h

@@ -0,0 +1,19 @@
+#ifndef _KERNEL_LIBK_BM_H
+#define _KERNEL_LIBK_BM_H
+
+#include <libk/std.h>
+
+struct bm {
+  uint8_t *base;
+  size_t nbits;
+};
+
+void bm_init(struct bm *bm, uint8_t *base, size_t nbits);
+void bm_set(struct bm *bm, size_t k);
+bool bm_set_region(struct bm *bm, size_t k, size_t m);
+void bm_clear(struct bm *bm, size_t k);
+void bm_clear_region(struct bm *bm, size_t k, size_t m);
+bool bm_test(struct bm *bm, size_t k);
+bool bm_test_region(struct bm *bm, size_t k, size_t m);
+
+#endif // _KERNEL_LIBK_BM_H

kernel/libk/src.mk

@@ -1,7 +1,9 @@
 c += libk/string.c \
 		 libk/printf.c \
-		 libk/putchar_.c
+		 libk/putchar_.c \
+		 libk/bm.c
 
 o += libk/string.o \
 		 libk/printf.o \
-		 libk/putchar_.o
+		 libk/putchar_.o \
+		 libk/bm.o

kernel/libk/std.h

@@ -8,5 +8,6 @@
 #include <stddef.h>
 #include <stdint.h>
 #include <stdnoreturn.h>
+#include <stdatomic.h>
 
 #endif // _KERNEL_LIBK_STD_H