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1// SPDX-License-Identifier: GPL-2.02/*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/image.h>13#include <asm/memory.h>14#include <asm/sysreg.h>15 16#include "efistub.h"17 18static bool system_needs_vamap(void)19{20 const struct efi_smbios_type4_record *record;21 const u32 __aligned(1) *socid;22 const u8 *version;23 24 /*25 * Ampere eMAG, Altra, and Altra Max machines crash in SetTime() if26 * SetVirtualAddressMap() has not been called prior. Most Altra systems27 * can be identified by the SMCCC soc ID, which is conveniently exposed28 * via the type 4 SMBIOS records. Otherwise, test the processor version29 * field. eMAG systems all appear to have the processor version field30 * set to "eMAG".31 */32 record = (struct efi_smbios_type4_record *)efi_get_smbios_record(4);33 if (!record)34 return false;35 36 socid = (u32 *)record->processor_id;37 switch (*socid & 0xffff000f) {38 static char const altra[] = "Ampere(TM) Altra(TM) Processor";39 static char const emag[] = "eMAG";40 41 default:42 version = efi_get_smbios_string(record, processor_version);43 if (!version || (strncmp(version, altra, sizeof(altra) - 1) &&44 strncmp(version, emag, sizeof(emag) - 1)))45 break;46 47 fallthrough;48 49 case 0x0a160001: // Altra50 case 0x0a160002: // Altra Max51 efi_warn("Working around broken SetVirtualAddressMap()\n");52 return true;53 }54 55 return false;56}57 58efi_status_t check_platform_features(void)59{60 u64 tg;61 62 /*63 * If we have 48 bits of VA space for TTBR0 mappings, we can map the64 * UEFI runtime regions 1:1 and so calling SetVirtualAddressMap() is65 * unnecessary.66 */67 if (VA_BITS_MIN >= 48 && !system_needs_vamap())68 efi_novamap = true;69 70 /* UEFI mandates support for 4 KB granularity, no need to check */71 if (IS_ENABLED(CONFIG_ARM64_4K_PAGES))72 return EFI_SUCCESS;73 74 tg = (read_cpuid(ID_AA64MMFR0_EL1) >> ID_AA64MMFR0_EL1_TGRAN_SHIFT) & 0xf;75 if (tg < ID_AA64MMFR0_EL1_TGRAN_SUPPORTED_MIN || tg > ID_AA64MMFR0_EL1_TGRAN_SUPPORTED_MAX) {76 if (IS_ENABLED(CONFIG_ARM64_64K_PAGES))77 efi_err("This 64 KB granular kernel is not supported by your CPU\n");78 else79 efi_err("This 16 KB granular kernel is not supported by your CPU\n");80 return EFI_UNSUPPORTED;81 }82 return EFI_SUCCESS;83}84 85#ifdef CONFIG_ARM64_WORKAROUND_CLEAN_CACHE86#define DCTYPE "civac"87#else88#define DCTYPE "cvau"89#endif90 91u32 __weak code_size;92 93void efi_cache_sync_image(unsigned long image_base,94 unsigned long alloc_size)95{96 u32 ctr = read_cpuid_effective_cachetype();97 u64 lsize = 4 << cpuid_feature_extract_unsigned_field(ctr,98 CTR_EL0_DminLine_SHIFT);99 100 /* only perform the cache maintenance if needed for I/D coherency */101 if (!(ctr & BIT(CTR_EL0_IDC_SHIFT))) {102 unsigned long base = image_base;103 unsigned long size = code_size;104 105 do {106 asm("dc " DCTYPE ", %0" :: "r"(base));107 base += lsize;108 size -= lsize;109 } while (size >= lsize);110 }111 112 asm("ic ialluis");113 dsb(ish);114 isb();115 116 efi_remap_image(image_base, alloc_size, code_size);117}118 119unsigned long __weak primary_entry_offset(void)120{121 /*122 * By default, we can invoke the kernel via the branch instruction in123 * the image header, so offset #0. This will be overridden by the EFI124 * stub build that is linked into the core kernel, as in that case, the125 * image header may not have been loaded into memory, or may be mapped126 * with non-executable permissions.127 */128 return 0;129}130 131void __noreturn efi_enter_kernel(unsigned long entrypoint,132 unsigned long fdt_addr,133 unsigned long fdt_size)134{135 void (* __noreturn enter_kernel)(u64, u64, u64, u64);136 137 enter_kernel = (void *)entrypoint + primary_entry_offset();138 enter_kernel(fdt_addr, 0, 0, 0);139}140