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path: root/drivers/firmware/efi/libstub/mem.c
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Diffstat (limited to 'drivers/firmware/efi/libstub/mem.c')
-rw-r--r--drivers/firmware/efi/libstub/mem.c130
1 files changed, 130 insertions, 0 deletions
diff --git a/drivers/firmware/efi/libstub/mem.c b/drivers/firmware/efi/libstub/mem.c
new file mode 100644
index 0000000000..4f1fa30223
--- /dev/null
+++ b/drivers/firmware/efi/libstub/mem.c
@@ -0,0 +1,130 @@
+// 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;
+
+ max = min(max, EFI_ALLOC_LIMIT);
+
+ if (EFI_ALLOC_ALIGN > EFI_PAGE_SIZE)
+ return efi_allocate_pages_aligned(size, addr, max,
+ EFI_ALLOC_ALIGN,
+ EFI_LOADER_DATA);
+
+ 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);
+}