make alloc_pages_at() able to allocate noncontiguous physical pages

1 files changed, 30 insertions, 3 deletions

diff --git a/kernel/memory/physalloc.h b/kernel/memory/physalloc.h
index d91c57a..e279409 100644
--- a/kernel/memory/physalloc.h
+++ b/kernel/memory/physalloc.h
@@ -11,11 +11,31 @@
 
 #include <comus/memory.h>
 
+/// Represents some contiguous physical pages
+struct phys_page_slice {
+	void *pagestart;
+	size_t num_pages;
+};
+
+#define PHYS_PAGE_SLICE_NULL \
+	((struct phys_page_slice){ .pagestart = NULL, .num_pages = 0 })
+
 /**
  * Initalize the physical page allocator
  */
 void physalloc_init(struct memory_map *map);
 
+/*
+ * Allocates the first page(s) it finds. Returns a pointer to that page
+ * and, if there are (up to max_pages) extra pages free after it, it allocates
+ * them as well.
+ *
+ * @param max_pages - the maximum number of pages to mark as allocated
+ * @returns a slice of all of the allocated pages, num_pages will be
+ * <= max_pages
+ */
+struct phys_page_slice alloc_phys_page_withextra(size_t max_pages);
+
 /**
  * Allocates a single physical page in memory
  * @preturns the physical address of the page
@@ -23,10 +43,11 @@ void physalloc_init(struct memory_map *map);
 void *alloc_phys_page(void);
 
 /**
- * Allocates count physical pages in memory
- * @returns the physical address of the first page
+ * Allocates count contiguous physical pages in memory
+ * @returns the physical address of the first page, or NULL if no
+ * contiguous pages exist.
  */
-void *alloc_phys_pages(size_t count);
+void *alloc_phys_pages_exact(size_t count);
 
 /**
 * Frees a single physical page in memory
@@ -41,4 +62,10 @@ void free_phys_page(void *ptr);
  */
 void free_phys_pages(void *ptr, size_t count);
 
+/**
+ * Frees a slice of physical pages in memory
+ * @param slice - the pages to free
+ */
+void free_phys_pages_slice(struct phys_page_slice slice);
+
 #endif /* physalloc.h */