--- Gnu-Mach/i386/i386at/biosmem.h	2020/09/02 04:53:39	1.1
+++ Gnu-Mach/i386/i386at/biosmem.h	2020/09/02 04:55:40	1.1.1.2
@@ -40,36 +40,51 @@
 #define BIOSMEM_END         0x100000
 
 /*
- * Early initialization of the biosmem module.
+ * Report reserved addresses to the biosmem module.
  *
- * This function processes the given multiboot data for BIOS-provided
- * memory information, and sets up a bootstrap physical page allocator.
+ * Once all boot data have been registered, the user can set up the
+ * early page allocator.
  *
- * It is called before paging is enabled.
+ * If the range is marked temporary, it will be unregistered when
+ * biosmem_free_usable() is called, so that pages that used to store
+ * these boot data may be released to the VM system.
+ */
+void biosmem_register_boot_data(phys_addr_t start, phys_addr_t end,
+                                boolean_t temporary);
+
+/*
+ * Initialize the early page allocator.
+ *
+ * This function uses the memory map provided by the boot loader along
+ * with the registered boot data addresses to set up a heap of free pages
+ * of physical memory.
+ *
+ * Note that on Xen, this function registers all the Xen boot information
+ * as boot data itself.
  */
 #ifdef MACH_HYP
 void biosmem_xen_bootstrap(void);
 #else /* MACH_HYP */
-void biosmem_bootstrap(struct multiboot_raw_info *mbi);
+void biosmem_bootstrap(const struct multiboot_raw_info *mbi);
 #endif /* MACH_HYP */
 
 /*
  * Allocate contiguous physical pages during bootstrap.
  *
- * This function is called before paging is enabled. It should only be used
- * to allocate initial page table pages. Those pages are later loaded into
- * the VM system (as reserved pages) which means they can be freed like other
- * regular pages. Users should fix up the type of those pages once the VM
- * system is initialized.
+ * The pages returned are guaranteed to be part of the direct physical
+ * mapping when paging is enabled.
+ *
+ * This function should only be used to allocate initial page table pages.
+ * Those pages are later loaded into the VM system (as reserved pages)
+ * which means they can be freed like other regular pages. Users should
+ * fix up the type of those pages once the VM system is initialized.
  */
 unsigned long biosmem_bootalloc(unsigned int nr_pages);
 
 /*
- * Return the amount of physical memory that can be directly mapped.
- *
- * This includes the size of both the DMA/DMA32 and DIRECTMAP segments.
+ * Return the limit of physical memory that can be directly mapped.
  */
-phys_addr_t biosmem_directmap_size(void);
+phys_addr_t biosmem_directmap_end(void);
 
 /*
  * Set up physical memory based on the information obtained during bootstrap
@@ -80,8 +95,8 @@ void biosmem_setup(void);
 /*
  * Free all usable memory.
  *
- * This includes ranges that weren't part of the bootstrap allocator initial
- * heap, e.g. because they contained boot data.
+ * This function releases all pages that aren't used by boot data and have
+ * not already been loaded into the VM system.
  */
 void biosmem_free_usable(void);