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
25static 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 */
37static 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
54static __initdata unsigned long screen_info_table = EFI_INVALID_TABLE_ADDR;
55static __initdata unsigned long cpu_state_table = EFI_INVALID_TABLE_ADDR;
56
57static 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
63static 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
87static 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);
126out:
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 */
134static __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
165static __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
209void __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
279static 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
290static 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 */
319static int efifb_add_links(const struct fwnode_handle *fwnode,
320			   struct device *dev)
321{
322	struct device_node *sup_np;
323	struct device *sup_dev;
324
325	sup_np = find_pci_overlap_node();
326
327	/*
328	 * If there's no PCI graphics controller backing the efifb, we are
329	 * done here.
330	 */
331	if (!sup_np)
332		return 0;
333
334	sup_dev = get_dev_from_fwnode(&sup_np->fwnode);
335	of_node_put(sup_np);
336
337	/*
338	 * Return -ENODEV if the PCI graphics controller device hasn't been
339	 * registered yet.  This ensures that efifb isn't allowed to probe
340	 * and this function is retried again when new devices are
341	 * registered.
342	 */
343	if (!sup_dev)
344		return -ENODEV;
345
346	/*
347	 * If this fails, retrying this function at a later point won't
348	 * change anything. So, don't return an error after this.
349	 */
350	if (!device_link_add(dev, sup_dev, fw_devlink_get_flags()))
351		dev_warn(dev, "device_link_add() failed\n");
352
353	put_device(sup_dev);
354
355	return 0;
356}
357
358static const struct fwnode_operations efifb_fwnode_ops = {
359	.add_links = efifb_add_links,
360};
361
362static struct fwnode_handle efifb_fwnode = {
363	.ops = &efifb_fwnode_ops,
364};
365
366static int __init register_gop_device(void)
367{
368	struct platform_device *pd;
369	int err;
370
371	if (screen_info.orig_video_isVGA != VIDEO_TYPE_EFI)
372		return 0;
373
374	pd = platform_device_alloc("efi-framebuffer", 0);
375	if (!pd)
376		return -ENOMEM;
377
378	if (IS_ENABLED(CONFIG_PCI))
379		pd->dev.fwnode = &efifb_fwnode;
380
381	err = platform_device_add_data(pd, &screen_info, sizeof(screen_info));
382	if (err)
383		return err;
384
385	return platform_device_add(pd);
386}
387subsys_initcall(register_gop_device);
388