1 files changed, 127 insertions, 0 deletions
diff --git a/drivers/firmware/efi/libstub/mem.c b/drivers/firmware/efi/libstub/mem.c
new file mode 100644
index 000000000..45841ef55
--- /dev/null
+++ b/drivers/firmware/efi/libstub/mem.c
@@ -0,0 +1,127 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#include <linux/efi.h>
+#include <asm/efi.h>
+
+#include "efistub.h"
+
+/**
+ * efi_get_memory_map() - get memory map
+ * @map:		pointer to memory map pointer to which to assign the
+ *			newly allocated memory map
+ * @install_cfg_tbl:	whether or not to install the boot memory map as a
+ *			configuration table
+ *
+ * Retrieve the UEFI memory map. The allocated memory leaves room for
+ * up to EFI_MMAP_NR_SLACK_SLOTS additional memory map entries.
+ *
+ * Return:	status code
+ */
+efi_status_t efi_get_memory_map(struct efi_boot_memmap **map,
+				bool install_cfg_tbl)
+{
+	int memtype = install_cfg_tbl ? EFI_ACPI_RECLAIM_MEMORY
+				      : EFI_LOADER_DATA;
+	efi_guid_t tbl_guid = LINUX_EFI_BOOT_MEMMAP_GUID;
+	struct efi_boot_memmap *m, tmp;
+	efi_status_t status;
+	unsigned long size;
+
+	tmp.map_size = 0;
+	status = efi_bs_call(get_memory_map, &tmp.map_size, NULL, &tmp.map_key,
+			     &tmp.desc_size, &tmp.desc_ver);
+	if (status != EFI_BUFFER_TOO_SMALL)
+		return EFI_LOAD_ERROR;
+
+	size = tmp.map_size + tmp.desc_size * EFI_MMAP_NR_SLACK_SLOTS;
+	status = efi_bs_call(allocate_pool, memtype, sizeof(*m) + size,
+			     (void **)&m);
+	if (status != EFI_SUCCESS)
+		return status;
+
+	if (install_cfg_tbl) {
+		/*
+		 * Installing a configuration table might allocate memory, and
+		 * this may modify the memory map. This means we should install
+		 * the configuration table first, and re-install or delete it
+		 * as needed.
+		 */
+		status = efi_bs_call(install_configuration_table, &tbl_guid, m);
+		if (status != EFI_SUCCESS)
+			goto free_map;
+	}
+
+	m->buff_size = m->map_size = size;
+	status = efi_bs_call(get_memory_map, &m->map_size, m->map, &m->map_key,
+			     &m->desc_size, &m->desc_ver);
+	if (status != EFI_SUCCESS)
+		goto uninstall_table;
+
+	*map = m;
+	return EFI_SUCCESS;
+
+uninstall_table:
+	if (install_cfg_tbl)
+		efi_bs_call(install_configuration_table, &tbl_guid, NULL);
+free_map:
+	efi_bs_call(free_pool, m);
+	return status;
+}
+
+/**
+ * efi_allocate_pages() - Allocate memory pages
+ * @size:	minimum number of bytes to allocate
+ * @addr:	On return the address of the first allocated page. The first
+ *		allocated page has alignment EFI_ALLOC_ALIGN which is an
+ *		architecture dependent multiple of the page size.
+ * @max:	the address that the last allocated memory page shall not
+ *		exceed
+ *
+ * Allocate pages as EFI_LOADER_DATA. The allocated pages are aligned according
+ * to EFI_ALLOC_ALIGN. The last allocated page will not exceed the address
+ * given by @max.
+ *
+ * Return:	status code
+ */
+efi_status_t efi_allocate_pages(unsigned long size, unsigned long *addr,
+				unsigned long max)
+{
+	efi_physical_addr_t alloc_addr;
+	efi_status_t status;
+
+	if (EFI_ALLOC_ALIGN > EFI_PAGE_SIZE)
+		return efi_allocate_pages_aligned(size, addr, max,
+						  EFI_ALLOC_ALIGN);
+
+	alloc_addr = ALIGN_DOWN(max + 1, EFI_ALLOC_ALIGN) - 1;
+	status = efi_bs_call(allocate_pages, EFI_ALLOCATE_MAX_ADDRESS,
+			     EFI_LOADER_DATA, DIV_ROUND_UP(size, EFI_PAGE_SIZE),
+			     &alloc_addr);
+	if (status != EFI_SUCCESS)
+		return status;
+
+	*addr = alloc_addr;
+	return EFI_SUCCESS;
+}
+
+/**
+ * efi_free() - free memory pages
+ * @size:	size of the memory area to free in bytes
+ * @addr:	start of the memory area to free (must be EFI_PAGE_SIZE
+ *		aligned)
+ *
+ * @size is rounded up to a multiple of EFI_ALLOC_ALIGN which is an
+ * architecture specific multiple of EFI_PAGE_SIZE. So this function should
+ * only be used to return pages allocated with efi_allocate_pages() or
+ * efi_low_alloc_above().
+ */
+void efi_free(unsigned long size, unsigned long addr)
+{
+	unsigned long nr_pages;
+
+	if (!size)
+		return;
+
+	nr_pages = round_up(size, EFI_ALLOC_ALIGN) / EFI_PAGE_SIZE;
+	efi_bs_call(free_pages, addr, nr_pages);
+}