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 Altra machines crash in SetTime() if SetVirtualAddressMap()
  23          * has not been called prior.
  24          */
  25         if (!type1_family || strcmp(type1_family, "Altra"))
  26                 return false;
  27
  28         efi_warn("Working around broken SetVirtualAddressMap()\n");
  29         return true;
  30 }
  31
  32 efi_status_t check_platform_features(void)
  33 {
  34         u64 tg;
  35
  36         /*
  37          * If we have 48 bits of VA space for TTBR0 mappings, we can map the
  38          * UEFI runtime regions 1:1 and so calling SetVirtualAddressMap() is
  39          * unnecessary.
  40          */
  41         if (VA_BITS_MIN >= 48 && !system_needs_vamap())
  42                 efi_novamap = true;
  43
  44         /* UEFI mandates support for 4 KB granularity, no need to check */
  45         if (IS_ENABLED(CONFIG_ARM64_4K_PAGES))
  46                 return EFI_SUCCESS;
  47
  48         tg = (read_cpuid(ID_AA64MMFR0_EL1) >> ID_AA64MMFR0_EL1_TGRAN_SHIFT) & 0xf;
  49         if (tg < ID_AA64MMFR0_EL1_TGRAN_SUPPORTED_MIN || tg > ID_AA64MMFR0_EL1_TGRAN_SUPPORTED_MAX) {
  50                 if (IS_ENABLED(CONFIG_ARM64_64K_PAGES))
  51                         efi_err("This 64 KB granular kernel is not supported by your CPU\n");
  52                 else
  53                         efi_err("This 16 KB granular kernel is not supported by your CPU\n");
  54                 return EFI_UNSUPPORTED;
  55         }
  56         return EFI_SUCCESS;
  57 }
  58
  59 void efi_cache_sync_image(unsigned long image_base,
  60                           unsigned long alloc_size,
  61                           unsigned long code_size)
  62 {
  63         u32 ctr = read_cpuid_effective_cachetype();
  64         u64 lsize = 4 << cpuid_feature_extract_unsigned_field(ctr,
  65                                                 CTR_EL0_DminLine_SHIFT);
  66
  67         do {
  68                 asm("dc civac, %0" :: "r"(image_base));
  69                 image_base += lsize;
  70                 alloc_size -= lsize;
  71         } while (alloc_size >= lsize);
  72
  73         asm("ic ialluis");
  74         dsb(ish);
  75         isb();
  76 }