Merge tag 'efi-urgent-2020-05-24' of git://git.kernel.org/pub/scm/linux/kernel/git...

[sfrench/cifs-2.6.git] / drivers / firmware / efi / libstub / x86-stub.c

diff --git a/drivers/firmware/efi/libstub/x86-stub.c b/drivers/firmware/efi/libstub/x86-stub.c
index 05ccb229fb45ffbb24df88bbb1f90ffb5ec73f77..f0339b5d3658dc8d282484a93e825e8ac962c896 100644 (file)
--- a/drivers/firmware/efi/libstub/x86-stub.c
+++ b/drivers/firmware/efi/libstub/x86-stub.c
@@ -606,24 +606,18 @@ static efi_status_t allocate_e820(struct boot_params *params,
                                  struct setup_data **e820ext,
                                  u32 *e820ext_size)
 {
-       unsigned long map_size, desc_size, buff_size;
-       struct efi_boot_memmap boot_map;
-       efi_memory_desc_t *map;
+       unsigned long map_size, desc_size, map_key;
        efi_status_t status;
-       __u32 nr_desc;
+       __u32 nr_desc, desc_version;
 
-       boot_map.map            = ↦
-       boot_map.map_size       = &map_size;
-       boot_map.desc_size      = &desc_size;
-       boot_map.desc_ver       = NULL;
-       boot_map.key_ptr        = NULL;
-       boot_map.buff_size      = &buff_size;
+       /* Only need the size of the mem map and size of each mem descriptor */
+       map_size = 0;
+       status = efi_bs_call(get_memory_map, &map_size, NULL, &map_key,
+                            &desc_size, &desc_version);
+       if (status != EFI_BUFFER_TOO_SMALL)
+               return (status != EFI_SUCCESS) ? status : EFI_UNSUPPORTED;
 
-       status = efi_get_memory_map(&boot_map);
-       if (status != EFI_SUCCESS)
-               return status;
-
-       nr_desc = buff_size / desc_size;
+       nr_desc = map_size / desc_size + EFI_MMAP_NR_SLACK_SLOTS;
 
        if (nr_desc > ARRAY_SIZE(params->e820_table)) {
                u32 nr_e820ext = nr_desc - ARRAY_SIZE(params->e820_table);