drivers/firmware/efi/libstub/arm64.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Copyright (C) 2013, 2014 Linaro Ltd;  <roy.franz@linaro.org>
   4  *
   5  * This file implements the EFI boot stub for the arm64 kernel.
   6  * Adapted from ARM version by Mark Salter <msalter@redhat.com>
   7  */
   8
   9
  10 #include <linux/efi.h>
  11 #include <asm/efi.h>
  12 #include <asm/memory.h>
  13 #include <asm/sysreg.h>
  14
  15 #include "efistub.h"
  16
  17 static bool system_needs_vamap(void)
  18 {
  19         const u8 *type1_family = efi_get_smbios_string(1, family);
  20
  21         /*
  22          * Ampere eMAG, Altra, and Altra Max machines crash in SetTime() if
  23          * SetVirtualAddressMap() has not been called prior.
  24          */
  25         if (!type1_family || (
  26             strcmp(type1_family, "eMAG") &&
  27             strcmp(type1_family, "Altra") &&
  28             strcmp(type1_family, "Altra Max")))
  29                 return false;
  30
  31         efi_warn("Working around broken SetVirtualAddressMap()\n");
  32         return true;
  33 }
  34
  35 efi_status_t check_platform_features(void)
  36 {
  37         u64 tg;
  38
  39         /*
  40          * If we have 48 bits of VA space for TTBR0 mappings, we can map the
  41          * UEFI runtime regions 1:1 and so calling SetVirtualAddressMap() is
  42          * unnecessary.
  43          */
  44         if (VA_BITS_MIN >= 48 && !system_needs_vamap())
  45                 efi_novamap = true;
  46
  47         /* UEFI mandates support for 4 KB granularity, no need to check */
  48         if (IS_ENABLED(CONFIG_ARM64_4K_PAGES))
  49                 return EFI_SUCCESS;
  50
  51         tg = (read_cpuid(ID_AA64MMFR0_EL1) >> ID_AA64MMFR0_EL1_TGRAN_SHIFT) & 0xf;
  52         if (tg < ID_AA64MMFR0_EL1_TGRAN_SUPPORTED_MIN || tg > ID_AA64MMFR0_EL1_TGRAN_SUPPORTED_MAX) {
  53                 if (IS_ENABLED(CONFIG_ARM64_64K_PAGES))
  54                         efi_err("This 64 KB granular kernel is not supported by your CPU\n");
  55                 else
  56                         efi_err("This 16 KB granular kernel is not supported by your CPU\n");
  57                 return EFI_UNSUPPORTED;
  58         }
  59         return EFI_SUCCESS;
  60 }
  61
  62 void efi_cache_sync_image(unsigned long image_base,
  63                           unsigned long alloc_size,
  64                           unsigned long code_size)
  65 {
  66         u32 ctr = read_cpuid_effective_cachetype();
  67         u64 lsize = 4 << cpuid_feature_extract_unsigned_field(ctr,
  68                                                 CTR_EL0_DminLine_SHIFT);
  69
  70         do {
  71                 asm("dc civac, %0" :: "r"(image_base));
  72                 image_base += lsize;
  73                 alloc_size -= lsize;
  74         } while (alloc_size >= lsize);
  75
  76         asm("ic ialluis");
  77         dsb(ish);
  78         isb();
  79 }