vm: verbatim import of x15's physical page allocator

1 files changed, 84 insertions, 0 deletions

diff --git a/i386/i386at/biosmem.h b/i386/i386at/biosmem.h
new file mode 100644
index 0000000..b32e027
--- /dev/null
+++ b/i386/i386at/biosmem.h
@@ -0,0 +1,84 @@
+/*
+ * Copyright (c) 2010-2014 Richard Braun.
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#ifndef _X86_BIOSMEM_H
+#define _X86_BIOSMEM_H
+
+#include <kern/types.h>
+#include <machine/multiboot.h>
+
+/*
+ * Address where the address of the Extended BIOS Data Area segment can be
+ * found.
+ */
+#define BIOSMEM_EBDA_PTR 0x40e
+
+/*
+ * Significant low memory addresses.
+ *
+ * The first 64 KiB are reserved for various reasons (e.g. to preserve BIOS
+ * data and to work around data corruption on some hardware).
+ */
+#define BIOSMEM_BASE        0x010000
+#define BIOSMEM_BASE_END    0x0a0000
+#define BIOSMEM_EXT_ROM     0x0e0000
+#define BIOSMEM_ROM         0x0f0000
+#define BIOSMEM_END         0x100000
+
+/*
+ * Early initialization of the biosmem module.
+ *
+ * This function processes the given multiboot data for BIOS-provided
+ * memory information, and sets up a bootstrap physical page allocator.
+ *
+ * It is called before paging is enabled.
+ */
+void biosmem_bootstrap(struct multiboot_raw_info *mbi);
+
+/*
+ * 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.
+ */
+void * 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.
+ */
+phys_addr_t biosmem_directmap_size(void);
+
+/*
+ * Set up physical memory based on the information obtained during bootstrap
+ * and load it in the VM system.
+ */
+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.
+ */
+void biosmem_free_usable(void);
+
+#endif /* _X86_BIOSMEM_H */