1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * Copyright (C) 2013 Linaro Ltd; <roy.franz@linaro.org> 4 */ 5 #include <linux/efi.h> 6 #include <asm/efi.h> 7 8 #include "efistub.h" 9 10 static efi_guid_t cpu_state_guid = LINUX_EFI_ARM_CPU_STATE_TABLE_GUID; 11 12 struct efi_arm_entry_state *efi_entry_state; 13 14 static void get_cpu_state(u32 *cpsr, u32 *sctlr) 15 { 16 asm("mrs %0, cpsr" : "=r"(*cpsr)); 17 if ((*cpsr & MODE_MASK) == HYP_MODE) 18 asm("mrc p15, 4, %0, c1, c0, 0" : "=r"(*sctlr)); 19 else 20 asm("mrc p15, 0, %0, c1, c0, 0" : "=r"(*sctlr)); 21 } 22 23 efi_status_t check_platform_features(void) 24 { 25 efi_status_t status; 26 u32 cpsr, sctlr; 27 int block; 28 29 get_cpu_state(&cpsr, &sctlr); 30 31 efi_info("Entering in %s mode with MMU %sabled\n", 32 ((cpsr & MODE_MASK) == HYP_MODE) ? "HYP" : "SVC", 33 (sctlr & 1) ? "en" : "dis"); 34 35 status = efi_bs_call(allocate_pool, EFI_LOADER_DATA, 36 sizeof(*efi_entry_state), 37 (void **)&efi_entry_state); 38 if (status != EFI_SUCCESS) { 39 efi_err("allocate_pool() failed\n"); 40 return status; 41 } 42 43 efi_entry_state->cpsr_before_ebs = cpsr; 44 efi_entry_state->sctlr_before_ebs = sctlr; 45 46 status = efi_bs_call(install_configuration_table, &cpu_state_guid, 47 efi_entry_state); 48 if (status != EFI_SUCCESS) { 49 efi_err("install_configuration_table() failed\n"); 50 goto free_state; 51 } 52 53 /* non-LPAE kernels can run anywhere */ 54 if (!IS_ENABLED(CONFIG_ARM_LPAE)) 55 return EFI_SUCCESS; 56 57 /* LPAE kernels need compatible hardware */ 58 block = cpuid_feature_extract(CPUID_EXT_MMFR0, 0); 59 if (block < 5) { 60 efi_err("This LPAE kernel is not supported by your CPU\n"); 61 status = EFI_UNSUPPORTED; 62 goto drop_table; 63 } 64 return EFI_SUCCESS; 65 66 drop_table: 67 efi_bs_call(install_configuration_table, &cpu_state_guid, NULL); 68 free_state: 69 efi_bs_call(free_pool, efi_entry_state); 70 return status; 71 } 72 73 void efi_handle_post_ebs_state(void) 74 { 75 get_cpu_state(&efi_entry_state->cpsr_after_ebs, 76 &efi_entry_state->sctlr_after_ebs); 77 } 78 79 static efi_guid_t screen_info_guid = LINUX_EFI_ARM_SCREEN_INFO_TABLE_GUID; 80 81 struct screen_info *alloc_screen_info(void) 82 { 83 struct screen_info *si; 84 efi_status_t status; 85 86 /* 87 * Unlike on arm64, where we can directly fill out the screen_info 88 * structure from the stub, we need to allocate a buffer to hold 89 * its contents while we hand over to the kernel proper from the 90 * decompressor. 91 */ 92 status = efi_bs_call(allocate_pool, EFI_RUNTIME_SERVICES_DATA, 93 sizeof(*si), (void **)&si); 94 95 if (status != EFI_SUCCESS) 96 return NULL; 97 98 status = efi_bs_call(install_configuration_table, 99 &screen_info_guid, si); 100 if (status == EFI_SUCCESS) 101 return si; 102 103 efi_bs_call(free_pool, si); 104 return NULL; 105 } 106 107 void free_screen_info(struct screen_info *si) 108 { 109 if (!si) 110 return; 111 112 efi_bs_call(install_configuration_table, &screen_info_guid, NULL); 113 efi_bs_call(free_pool, si); 114 } 115 116 efi_status_t handle_kernel_image(unsigned long *image_addr, 117 unsigned long *image_size, 118 unsigned long *reserve_addr, 119 unsigned long *reserve_size, 120 efi_loaded_image_t *image, 121 efi_handle_t image_handle) 122 { 123 const int slack = TEXT_OFFSET - 5 * PAGE_SIZE; 124 int alloc_size = MAX_UNCOMP_KERNEL_SIZE + EFI_PHYS_ALIGN; 125 unsigned long alloc_base, kernel_base; 126 efi_status_t status; 127 128 /* 129 * Allocate space for the decompressed kernel as low as possible. 130 * The region should be 16 MiB aligned, but the first 'slack' bytes 131 * are not used by Linux, so we allow those to be occupied by the 132 * firmware. 133 */ 134 status = efi_low_alloc_above(alloc_size, EFI_PAGE_SIZE, &alloc_base, 0x0); 135 if (status != EFI_SUCCESS) { 136 efi_err("Unable to allocate memory for uncompressed kernel.\n"); 137 return status; 138 } 139 140 if ((alloc_base % EFI_PHYS_ALIGN) > slack) { 141 /* 142 * More than 'slack' bytes are already occupied at the base of 143 * the allocation, so we need to advance to the next 16 MiB block. 144 */ 145 kernel_base = round_up(alloc_base, EFI_PHYS_ALIGN); 146 efi_info("Free memory starts at 0x%lx, setting kernel_base to 0x%lx\n", 147 alloc_base, kernel_base); 148 } else { 149 kernel_base = round_down(alloc_base, EFI_PHYS_ALIGN); 150 } 151 152 *reserve_addr = kernel_base + slack; 153 *reserve_size = MAX_UNCOMP_KERNEL_SIZE; 154 155 /* now free the parts that we will not use */ 156 if (*reserve_addr > alloc_base) { 157 efi_bs_call(free_pages, alloc_base, 158 (*reserve_addr - alloc_base) / EFI_PAGE_SIZE); 159 alloc_size -= *reserve_addr - alloc_base; 160 } 161 efi_bs_call(free_pages, *reserve_addr + MAX_UNCOMP_KERNEL_SIZE, 162 (alloc_size - MAX_UNCOMP_KERNEL_SIZE) / EFI_PAGE_SIZE); 163 164 *image_addr = kernel_base + TEXT_OFFSET; 165 *image_size = 0; 166 167 efi_debug("image addr == 0x%lx, reserve_addr == 0x%lx\n", 168 *image_addr, *reserve_addr); 169 170 return EFI_SUCCESS; 171 } 172