drivers/firmware/efi/libstub/arm32-stub.c

   1 /*
   2  * Copyright (C) 2013 Linaro Ltd;  <roy.franz@linaro.org>
   3  *
   4  * This program is free software; you can redistribute it and/or modify
   5  * it under the terms of the GNU General Public License version 2 as
   6  * published by the Free Software Foundation.
   7  *
   8  */
   9 #include <linux/efi.h>
  10 #include <asm/efi.h>
  11
  12 efi_status_t check_platform_features(efi_system_table_t *sys_table_arg)
  13 {
  14         int block;
  15
  16         /* non-LPAE kernels can run anywhere */
  17         if (!IS_ENABLED(CONFIG_ARM_LPAE))
  18                 return EFI_SUCCESS;
  19
  20         /* LPAE kernels need compatible hardware */
  21         block = cpuid_feature_extract(CPUID_EXT_MMFR0, 0);
  22         if (block < 5) {
  23                 pr_efi_err(sys_table_arg, "This LPAE kernel is not supported by your CPU\n");
  24                 return EFI_UNSUPPORTED;
  25         }
  26         return EFI_SUCCESS;
  27 }
  28
  29 static efi_guid_t screen_info_guid = LINUX_EFI_ARM_SCREEN_INFO_TABLE_GUID;
  30
  31 struct screen_info *alloc_screen_info(efi_system_table_t *sys_table_arg)
  32 {
  33         struct screen_info *si;
  34         efi_status_t status;
  35
  36         /*
  37          * Unlike on arm64, where we can directly fill out the screen_info
  38          * structure from the stub, we need to allocate a buffer to hold
  39          * its contents while we hand over to the kernel proper from the
  40          * decompressor.
  41          */
  42         status = efi_call_early(allocate_pool, EFI_RUNTIME_SERVICES_DATA,
  43                                 sizeof(*si), (void **)&si);
  44
  45         if (status != EFI_SUCCESS)
  46                 return NULL;
  47
  48         status = efi_call_early(install_configuration_table,
  49                                 &screen_info_guid, si);
  50         if (status == EFI_SUCCESS)
  51                 return si;
  52
  53         efi_call_early(free_pool, si);
  54         return NULL;
  55 }
  56
  57 void free_screen_info(efi_system_table_t *sys_table_arg, struct screen_info *si)
  58 {
  59         if (!si)
  60                 return;
  61
  62         efi_call_early(install_configuration_table, &screen_info_guid, NULL);
  63         efi_call_early(free_pool, si);
  64 }
  65
  66 efi_status_t handle_kernel_image(efi_system_table_t *sys_table,
  67                                  unsigned long *image_addr,
  68                                  unsigned long *image_size,
  69                                  unsigned long *reserve_addr,
  70                                  unsigned long *reserve_size,
  71                                  unsigned long dram_base,
  72                                  efi_loaded_image_t *image)
  73 {
  74         unsigned long nr_pages;
  75         efi_status_t status;
  76         /* Use alloc_addr to tranlsate between types */
  77         efi_physical_addr_t alloc_addr;
  78
  79         /*
  80          * Verify that the DRAM base address is compatible with the ARM
  81          * boot protocol, which determines the base of DRAM by masking
  82          * off the low 27 bits of the address at which the zImage is
  83          * loaded. These assumptions are made by the decompressor,
  84          * before any memory map is available.
  85          */
  86         dram_base = round_up(dram_base, SZ_128M);
  87
  88         /*
  89          * Reserve memory for the uncompressed kernel image. This is
  90          * all that prevents any future allocations from conflicting
  91          * with the kernel. Since we can't tell from the compressed
  92          * image how much DRAM the kernel actually uses (due to BSS
  93          * size uncertainty) we allocate the maximum possible size.
  94          * Do this very early, as prints can cause memory allocations
  95          * that may conflict with this.
  96          */
  97         alloc_addr = dram_base;
  98         *reserve_size = MAX_UNCOMP_KERNEL_SIZE;
  99         nr_pages = round_up(*reserve_size, EFI_PAGE_SIZE) / EFI_PAGE_SIZE;
 100         status = sys_table->boottime->allocate_pages(EFI_ALLOCATE_ADDRESS,
 101                                                      EFI_LOADER_DATA,
 102                                                      nr_pages, &alloc_addr);
 103         if (status != EFI_SUCCESS) {
 104                 *reserve_size = 0;
 105                 pr_efi_err(sys_table, "Unable to allocate memory for uncompressed kernel.\n");
 106                 return status;
 107         }
 108         *reserve_addr = alloc_addr;
 109
 110         /*
 111          * Relocate the zImage, so that it appears in the lowest 128 MB
 112          * memory window.
 113          */
 114         *image_size = image->image_size;
 115         status = efi_relocate_kernel(sys_table, image_addr, *image_size,
 116                                      *image_size,
 117                                      dram_base + MAX_UNCOMP_KERNEL_SIZE, 0);
 118         if (status != EFI_SUCCESS) {
 119                 pr_efi_err(sys_table, "Failed to relocate kernel.\n");
 120                 efi_free(sys_table, *reserve_size, *reserve_addr);
 121                 *reserve_size = 0;
 122                 return status;
 123         }
 124
 125         /*
 126          * Check to see if we were able to allocate memory low enough
 127          * in memory. The kernel determines the base of DRAM from the
 128          * address at which the zImage is loaded.
 129          */
 130         if (*image_addr + *image_size > dram_base + ZIMAGE_OFFSET_LIMIT) {
 131                 pr_efi_err(sys_table, "Failed to relocate kernel, no low memory available.\n");
 132                 efi_free(sys_table, *reserve_size, *reserve_addr);
 133                 *reserve_size = 0;
 134                 efi_free(sys_table, *image_size, *image_addr);
 135                 *image_size = 0;
 136                 return EFI_LOAD_ERROR;
 137         }
 138         return EFI_SUCCESS;
 139 }