1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * Extensible Firmware Interface
4 *
5 * Based on Extensible Firmware Interface Specification version 2.4
6 *
7 * Copyright (C) 2013 - 2015 Linaro Ltd.
8 */
9
10 #define pr_fmt(fmt) "efi: " fmt
11
12 #include <linux/efi.h>
13 #include <linux/fwnode.h>
14 #include <linux/init.h>
15 #include <linux/memblock.h>
16 #include <linux/mm_types.h>
17 #include <linux/of.h>
18 #include <linux/of_address.h>
19 #include <linux/of_fdt.h>
20 #include <linux/platform_device.h>
21 #include <linux/screen_info.h>
22
23 #include <asm/efi.h>
24
is_memory(efi_memory_desc_t * md)25 static int __init is_memory(efi_memory_desc_t *md)
26 {
27 if (md->attribute & (EFI_MEMORY_WB|EFI_MEMORY_WT|EFI_MEMORY_WC))
28 return 1;
29 return 0;
30 }
31
32 /*
33 * Translate a EFI virtual address into a physical address: this is necessary,
34 * as some data members of the EFI system table are virtually remapped after
35 * SetVirtualAddressMap() has been called.
36 */
efi_to_phys(unsigned long addr)37 static phys_addr_t __init efi_to_phys(unsigned long addr)
38 {
39 efi_memory_desc_t *md;
40
41 for_each_efi_memory_desc(md) {
42 if (!(md->attribute & EFI_MEMORY_RUNTIME))
43 continue;
44 if (md->virt_addr == 0)
45 /* no virtual mapping has been installed by the stub */
46 break;
47 if (md->virt_addr <= addr &&
48 (addr - md->virt_addr) < (md->num_pages << EFI_PAGE_SHIFT))
49 return md->phys_addr + addr - md->virt_addr;
50 }
51 return addr;
52 }
53
54 static __initdata unsigned long screen_info_table = EFI_INVALID_TABLE_ADDR;
55 static __initdata unsigned long cpu_state_table = EFI_INVALID_TABLE_ADDR;
56
57 static const efi_config_table_type_t arch_tables[] __initconst = {
58 {LINUX_EFI_ARM_SCREEN_INFO_TABLE_GUID, &screen_info_table},
59 {LINUX_EFI_ARM_CPU_STATE_TABLE_GUID, &cpu_state_table},
60 {}
61 };
62
init_screen_info(void)63 static void __init init_screen_info(void)
64 {
65 struct screen_info *si;
66
67 if (IS_ENABLED(CONFIG_ARM) &&
68 screen_info_table != EFI_INVALID_TABLE_ADDR) {
69 si = early_memremap_ro(screen_info_table, sizeof(*si));
70 if (!si) {
71 pr_err("Could not map screen_info config table\n");
72 return;
73 }
74 screen_info = *si;
75 early_memunmap(si, sizeof(*si));
76
77 /* dummycon on ARM needs non-zero values for columns/lines */
78 screen_info.orig_video_cols = 80;
79 screen_info.orig_video_lines = 25;
80 }
81
82 if (screen_info.orig_video_isVGA == VIDEO_TYPE_EFI &&
83 memblock_is_map_memory(screen_info.lfb_base))
84 memblock_mark_nomap(screen_info.lfb_base, screen_info.lfb_size);
85 }
86
uefi_init(u64 efi_system_table)87 static int __init uefi_init(u64 efi_system_table)
88 {
89 efi_config_table_t *config_tables;
90 efi_system_table_t *systab;
91 size_t table_size;
92 int retval;
93
94 systab = early_memremap_ro(efi_system_table, sizeof(efi_system_table_t));
95 if (systab == NULL) {
96 pr_warn("Unable to map EFI system table.\n");
97 return -ENOMEM;
98 }
99
100 set_bit(EFI_BOOT, &efi.flags);
101 if (IS_ENABLED(CONFIG_64BIT))
102 set_bit(EFI_64BIT, &efi.flags);
103
104 retval = efi_systab_check_header(&systab->hdr, 2);
105 if (retval)
106 goto out;
107
108 efi.runtime = systab->runtime;
109 efi.runtime_version = systab->hdr.revision;
110
111 efi_systab_report_header(&systab->hdr, efi_to_phys(systab->fw_vendor));
112
113 table_size = sizeof(efi_config_table_t) * systab->nr_tables;
114 config_tables = early_memremap_ro(efi_to_phys(systab->tables),
115 table_size);
116 if (config_tables == NULL) {
117 pr_warn("Unable to map EFI config table array.\n");
118 retval = -ENOMEM;
119 goto out;
120 }
121 retval = efi_config_parse_tables(config_tables, systab->nr_tables,
122 IS_ENABLED(CONFIG_ARM) ? arch_tables
123 : NULL);
124
125 early_memunmap(config_tables, table_size);
126 out:
127 early_memunmap(systab, sizeof(efi_system_table_t));
128 return retval;
129 }
130
131 /*
132 * Return true for regions that can be used as System RAM.
133 */
is_usable_memory(efi_memory_desc_t * md)134 static __init int is_usable_memory(efi_memory_desc_t *md)
135 {
136 switch (md->type) {
137 case EFI_LOADER_CODE:
138 case EFI_LOADER_DATA:
139 case EFI_ACPI_RECLAIM_MEMORY:
140 case EFI_BOOT_SERVICES_CODE:
141 case EFI_BOOT_SERVICES_DATA:
142 case EFI_CONVENTIONAL_MEMORY:
143 case EFI_PERSISTENT_MEMORY:
144 /*
145 * Special purpose memory is 'soft reserved', which means it
146 * is set aside initially, but can be hotplugged back in or
147 * be assigned to the dax driver after boot.
148 */
149 if (efi_soft_reserve_enabled() &&
150 (md->attribute & EFI_MEMORY_SP))
151 return false;
152
153 /*
154 * According to the spec, these regions are no longer reserved
155 * after calling ExitBootServices(). However, we can only use
156 * them as System RAM if they can be mapped writeback cacheable.
157 */
158 return (md->attribute & EFI_MEMORY_WB);
159 default:
160 break;
161 }
162 return false;
163 }
164
reserve_regions(void)165 static __init void reserve_regions(void)
166 {
167 efi_memory_desc_t *md;
168 u64 paddr, npages, size;
169
170 if (efi_enabled(EFI_DBG))
171 pr_info("Processing EFI memory map:\n");
172
173 /*
174 * Discard memblocks discovered so far: if there are any at this
175 * point, they originate from memory nodes in the DT, and UEFI
176 * uses its own memory map instead.
177 */
178 memblock_dump_all();
179 memblock_remove(0, PHYS_ADDR_MAX);
180
181 for_each_efi_memory_desc(md) {
182 paddr = md->phys_addr;
183 npages = md->num_pages;
184
185 if (efi_enabled(EFI_DBG)) {
186 char buf[64];
187
188 pr_info(" 0x%012llx-0x%012llx %s\n",
189 paddr, paddr + (npages << EFI_PAGE_SHIFT) - 1,
190 efi_md_typeattr_format(buf, sizeof(buf), md));
191 }
192
193 memrange_efi_to_native(&paddr, &npages);
194 size = npages << PAGE_SHIFT;
195
196 if (is_memory(md)) {
197 early_init_dt_add_memory_arch(paddr, size);
198
199 if (!is_usable_memory(md))
200 memblock_mark_nomap(paddr, size);
201
202 /* keep ACPI reclaim memory intact for kexec etc. */
203 if (md->type == EFI_ACPI_RECLAIM_MEMORY)
204 memblock_reserve(paddr, size);
205 }
206 }
207 }
208
efi_init(void)209 void __init efi_init(void)
210 {
211 struct efi_memory_map_data data;
212 u64 efi_system_table;
213
214 /* Grab UEFI information placed in FDT by stub */
215 efi_system_table = efi_get_fdt_params(&data);
216 if (!efi_system_table)
217 return;
218
219 if (efi_memmap_init_early(&data) < 0) {
220 /*
221 * If we are booting via UEFI, the UEFI memory map is the only
222 * description of memory we have, so there is little point in
223 * proceeding if we cannot access it.
224 */
225 panic("Unable to map EFI memory map.\n");
226 }
227
228 WARN(efi.memmap.desc_version != 1,
229 "Unexpected EFI_MEMORY_DESCRIPTOR version %ld",
230 efi.memmap.desc_version);
231
232 if (uefi_init(efi_system_table) < 0) {
233 efi_memmap_unmap();
234 return;
235 }
236
237 reserve_regions();
238 efi_esrt_init();
239 efi_mokvar_table_init();
240
241 memblock_reserve(data.phys_map & PAGE_MASK,
242 PAGE_ALIGN(data.size + (data.phys_map & ~PAGE_MASK)));
243
244 init_screen_info();
245
246 #ifdef CONFIG_ARM
247 /* ARM does not permit early mappings to persist across paging_init() */
248 efi_memmap_unmap();
249
250 if (cpu_state_table != EFI_INVALID_TABLE_ADDR) {
251 struct efi_arm_entry_state *state;
252 bool dump_state = true;
253
254 state = early_memremap_ro(cpu_state_table,
255 sizeof(struct efi_arm_entry_state));
256 if (state == NULL) {
257 pr_warn("Unable to map CPU entry state table.\n");
258 return;
259 }
260
261 if ((state->sctlr_before_ebs & 1) == 0)
262 pr_warn(FW_BUG "EFI stub was entered with MMU and Dcache disabled, please fix your firmware!\n");
263 else if ((state->sctlr_after_ebs & 1) == 0)
264 pr_warn(FW_BUG "ExitBootServices() returned with MMU and Dcache disabled, please fix your firmware!\n");
265 else
266 dump_state = false;
267
268 if (dump_state || efi_enabled(EFI_DBG)) {
269 pr_info("CPSR at EFI stub entry : 0x%08x\n", state->cpsr_before_ebs);
270 pr_info("SCTLR at EFI stub entry : 0x%08x\n", state->sctlr_before_ebs);
271 pr_info("CPSR after ExitBootServices() : 0x%08x\n", state->cpsr_after_ebs);
272 pr_info("SCTLR after ExitBootServices(): 0x%08x\n", state->sctlr_after_ebs);
273 }
274 early_memunmap(state, sizeof(struct efi_arm_entry_state));
275 }
276 #endif
277 }
278
efifb_overlaps_pci_range(const struct of_pci_range * range)279 static bool efifb_overlaps_pci_range(const struct of_pci_range *range)
280 {
281 u64 fb_base = screen_info.lfb_base;
282
283 if (screen_info.capabilities & VIDEO_CAPABILITY_64BIT_BASE)
284 fb_base |= (u64)(unsigned long)screen_info.ext_lfb_base << 32;
285
286 return fb_base >= range->cpu_addr &&
287 fb_base < (range->cpu_addr + range->size);
288 }
289
find_pci_overlap_node(void)290 static struct device_node *find_pci_overlap_node(void)
291 {
292 struct device_node *np;
293
294 for_each_node_by_type(np, "pci") {
295 struct of_pci_range_parser parser;
296 struct of_pci_range range;
297 int err;
298
299 err = of_pci_range_parser_init(&parser, np);
300 if (err) {
301 pr_warn("of_pci_range_parser_init() failed: %d\n", err);
302 continue;
303 }
304
305 for_each_of_pci_range(&parser, &range)
306 if (efifb_overlaps_pci_range(&range))
307 return np;
308 }
309 return NULL;
310 }
311
312 /*
313 * If the efifb framebuffer is backed by a PCI graphics controller, we have
314 * to ensure that this relation is expressed using a device link when
315 * running in DT mode, or the probe order may be reversed, resulting in a
316 * resource reservation conflict on the memory window that the efifb
317 * framebuffer steals from the PCIe host bridge.
318 */
efifb_add_links(struct fwnode_handle * fwnode)319 static int efifb_add_links(struct fwnode_handle *fwnode)
320 {
321 struct device_node *sup_np;
322
323 sup_np = find_pci_overlap_node();
324
325 /*
326 * If there's no PCI graphics controller backing the efifb, we are
327 * done here.
328 */
329 if (!sup_np)
330 return 0;
331
332 fwnode_link_add(fwnode, of_fwnode_handle(sup_np));
333 of_node_put(sup_np);
334
335 return 0;
336 }
337
338 static const struct fwnode_operations efifb_fwnode_ops = {
339 .add_links = efifb_add_links,
340 };
341
342 static struct fwnode_handle efifb_fwnode;
343
register_gop_device(void)344 static int __init register_gop_device(void)
345 {
346 struct platform_device *pd;
347 int err;
348
349 if (screen_info.orig_video_isVGA != VIDEO_TYPE_EFI)
350 return 0;
351
352 pd = platform_device_alloc("efi-framebuffer", 0);
353 if (!pd)
354 return -ENOMEM;
355
356 if (IS_ENABLED(CONFIG_PCI)) {
357 fwnode_init(&efifb_fwnode, &efifb_fwnode_ops);
358 pd->dev.fwnode = &efifb_fwnode;
359 }
360
361 err = platform_device_add_data(pd, &screen_info, sizeof(screen_info));
362 if (err)
363 return err;
364
365 return platform_device_add(pd);
366 }
367 subsys_initcall(register_gop_device);
368