2 * x86_64 specific EFI support functions
3 * Based on Extensible Firmware Interface Specification version 1.0
5 * Copyright (C) 2005-2008 Intel Co.
6 * Fenghua Yu <fenghua.yu@intel.com>
7 * Bibo Mao <bibo.mao@intel.com>
8 * Chandramouli Narayanan <mouli@linux.intel.com>
9 * Huang Ying <ying.huang@intel.com>
11 * Code to convert EFI to E820 map has been implemented in elilo bootloader
12 * based on a EFI patch by Edgar Hucek. Based on the E820 map, the page table
13 * is setup appropriately for EFI runtime code.
18 #include <linux/kernel.h>
19 #include <linux/init.h>
21 #include <linux/types.h>
22 #include <linux/spinlock.h>
23 #include <linux/bootmem.h>
24 #include <linux/ioport.h>
25 #include <linux/module.h>
26 #include <linux/efi.h>
27 #include <linux/uaccess.h>
29 #include <linux/reboot.h>
30 #include <linux/slab.h>
32 #include <asm/setup.h>
35 #include <asm/pgtable.h>
36 #include <asm/tlbflush.h>
37 #include <asm/proto.h>
39 #include <asm/cacheflush.h>
40 #include <asm/fixmap.h>
41 #include <asm/realmode.h>
44 static pgd_t *save_pgd __initdata;
45 static unsigned long efi_flags __initdata;
48 * We allocate runtime services regions bottom-up, starting from -4G, i.e.
49 * 0xffff_ffff_0000_0000 and limit EFI VA mapping space to 64G.
51 static u64 efi_va = -4 * (1UL << 30);
52 #define EFI_VA_END (-68 * (1UL << 30))
55 * Scratch space used for switching the pagetable in the EFI stub
65 static void __init early_code_mapping_set_exec(int executable)
67 efi_memory_desc_t *md;
70 if (!(__supported_pte_mask & _PAGE_NX))
73 /* Make EFI service code area executable */
74 for (p = memmap.map; p < memmap.map_end; p += memmap.desc_size) {
76 if (md->type == EFI_RUNTIME_SERVICES_CODE ||
77 md->type == EFI_BOOT_SERVICES_CODE)
78 efi_set_executable(md, executable);
82 void __init efi_call_phys_prolog(void)
84 unsigned long vaddress;
88 if (!efi_enabled(EFI_OLD_MEMMAP))
91 early_code_mapping_set_exec(1);
92 local_irq_save(efi_flags);
94 n_pgds = DIV_ROUND_UP((max_pfn << PAGE_SHIFT), PGDIR_SIZE);
95 save_pgd = kmalloc(n_pgds * sizeof(pgd_t), GFP_KERNEL);
97 for (pgd = 0; pgd < n_pgds; pgd++) {
98 save_pgd[pgd] = *pgd_offset_k(pgd * PGDIR_SIZE);
99 vaddress = (unsigned long)__va(pgd * PGDIR_SIZE);
100 set_pgd(pgd_offset_k(pgd * PGDIR_SIZE), *pgd_offset_k(vaddress));
105 void __init efi_call_phys_epilog(void)
108 * After the lock is released, the original page table is restored.
111 int n_pgds = DIV_ROUND_UP((max_pfn << PAGE_SHIFT) , PGDIR_SIZE);
113 if (!efi_enabled(EFI_OLD_MEMMAP))
116 for (pgd = 0; pgd < n_pgds; pgd++)
117 set_pgd(pgd_offset_k(pgd * PGDIR_SIZE), save_pgd[pgd]);
120 local_irq_restore(efi_flags);
121 early_code_mapping_set_exec(0);
125 * Add low kernel mappings for passing arguments to EFI functions.
127 void efi_sync_low_kernel_mappings(void)
130 pgd_t *pgd = (pgd_t *)__va(real_mode_header->trampoline_pgd);
132 if (efi_enabled(EFI_OLD_MEMMAP))
135 num_pgds = pgd_index(MODULES_END - 1) - pgd_index(PAGE_OFFSET);
137 memcpy(pgd + pgd_index(PAGE_OFFSET),
138 init_mm.pgd + pgd_index(PAGE_OFFSET),
139 sizeof(pgd_t) * num_pgds);
142 int __init efi_setup_page_tables(unsigned long pa_memmap, unsigned num_pages)
149 if (efi_enabled(EFI_OLD_MEMMAP))
152 efi_scratch.efi_pgt = (pgd_t *)(unsigned long)real_mode_header->trampoline_pgd;
153 pgd = __va(efi_scratch.efi_pgt);
156 * It can happen that the physical address of new_memmap lands in memory
157 * which is not mapped in the EFI page table. Therefore we need to go
158 * and ident-map those pages containing the map before calling
159 * phys_efi_set_virtual_address_map().
161 if (kernel_map_pages_in_pgd(pgd, pa_memmap, pa_memmap, num_pages, _PAGE_NX)) {
162 pr_err("Error ident-mapping new memmap (0x%lx)!\n", pa_memmap);
166 efi_scratch.use_pgd = true;
169 * When making calls to the firmware everything needs to be 1:1
170 * mapped and addressable with 32-bit pointers. Map the kernel
171 * text and allocate a new stack because we can't rely on the
172 * stack pointer being < 4GB.
174 if (!IS_ENABLED(CONFIG_EFI_MIXED))
177 page = alloc_page(GFP_KERNEL|__GFP_DMA32);
179 panic("Unable to allocate EFI runtime stack < 4GB\n");
181 efi_scratch.phys_stack = virt_to_phys(page_address(page));
182 efi_scratch.phys_stack += PAGE_SIZE; /* stack grows down */
184 npages = (_end - _text) >> PAGE_SHIFT;
187 if (kernel_map_pages_in_pgd(pgd, text >> PAGE_SHIFT, text, npages, 0)) {
188 pr_err("Failed to map kernel text 1:1\n");
195 void __init efi_cleanup_page_tables(unsigned long pa_memmap, unsigned num_pages)
197 pgd_t *pgd = (pgd_t *)__va(real_mode_header->trampoline_pgd);
199 kernel_unmap_pages_in_pgd(pgd, pa_memmap, num_pages);
202 static void __init __map_region(efi_memory_desc_t *md, u64 va)
204 pgd_t *pgd = (pgd_t *)__va(real_mode_header->trampoline_pgd);
205 unsigned long pf = 0;
207 if (!(md->attribute & EFI_MEMORY_WB))
210 if (kernel_map_pages_in_pgd(pgd, md->phys_addr, va, md->num_pages, pf))
211 pr_warn("Error mapping PA 0x%llx -> VA 0x%llx!\n",
215 void __init efi_map_region(efi_memory_desc_t *md)
217 unsigned long size = md->num_pages << PAGE_SHIFT;
218 u64 pa = md->phys_addr;
220 if (efi_enabled(EFI_OLD_MEMMAP))
221 return old_map_region(md);
224 * Make sure the 1:1 mappings are present as a catch-all for b0rked
225 * firmware which doesn't update all internal pointers after switching
226 * to virtual mode and would otherwise crap on us.
228 __map_region(md, md->phys_addr);
231 * Enforce the 1:1 mapping as the default virtual address when
232 * booting in EFI mixed mode, because even though we may be
233 * running a 64-bit kernel, the firmware may only be 32-bit.
235 if (!efi_is_native () && IS_ENABLED(CONFIG_EFI_MIXED)) {
236 md->virt_addr = md->phys_addr;
242 /* Is PA 2M-aligned? */
243 if (!(pa & (PMD_SIZE - 1))) {
246 u64 pa_offset = pa & (PMD_SIZE - 1);
247 u64 prev_va = efi_va;
249 /* get us the same offset within this 2M page */
250 efi_va = (efi_va & PMD_MASK) + pa_offset;
252 if (efi_va > prev_va)
256 if (efi_va < EFI_VA_END) {
257 pr_warn(FW_WARN "VA address range overflow!\n");
262 __map_region(md, efi_va);
263 md->virt_addr = efi_va;
267 * kexec kernel will use efi_map_region_fixed to map efi runtime memory ranges.
268 * md->virt_addr is the original virtual address which had been mapped in kexec
271 void __init efi_map_region_fixed(efi_memory_desc_t *md)
273 __map_region(md, md->virt_addr);
276 void __iomem *__init efi_ioremap(unsigned long phys_addr, unsigned long size,
277 u32 type, u64 attribute)
279 unsigned long last_map_pfn;
281 if (type == EFI_MEMORY_MAPPED_IO)
282 return ioremap(phys_addr, size);
284 last_map_pfn = init_memory_mapping(phys_addr, phys_addr + size);
285 if ((last_map_pfn << PAGE_SHIFT) < phys_addr + size) {
286 unsigned long top = last_map_pfn << PAGE_SHIFT;
287 efi_ioremap(top, size - (top - phys_addr), type, attribute);
290 if (!(attribute & EFI_MEMORY_WB))
291 efi_memory_uc((u64)(unsigned long)__va(phys_addr), size);
293 return (void __iomem *)__va(phys_addr);
296 void __init parse_efi_setup(u64 phys_addr, u32 data_len)
298 efi_setup = phys_addr + sizeof(struct setup_data);
301 void __init efi_runtime_mkexec(void)
303 if (!efi_enabled(EFI_OLD_MEMMAP))
306 if (__supported_pte_mask & _PAGE_NX)
307 runtime_code_page_mkexec();
310 void __init efi_dump_pagetable(void)
312 #ifdef CONFIG_EFI_PGT_DUMP
313 pgd_t *pgd = (pgd_t *)__va(real_mode_header->trampoline_pgd);
315 ptdump_walk_pgd_level(NULL, pgd);
319 #ifdef CONFIG_EFI_MIXED
320 extern efi_status_t efi64_thunk(u32, ...);
322 #define runtime_service32(func) \
324 u32 table = (u32)(unsigned long)efi.systab; \
327 rt = (u32 *)(table + offsetof(efi_system_table_32_t, runtime)); \
328 ___f = (u32 *)(*rt + offsetof(efi_runtime_services_32_t, func)); \
333 * Switch to the EFI page tables early so that we can access the 1:1
334 * runtime services mappings which are not mapped in any other page
335 * tables. This function must be called before runtime_service32().
337 * Also, disable interrupts because the IDT points to 64-bit handlers,
338 * which aren't going to function correctly when we switch to 32-bit.
340 #define efi_thunk(f, ...) \
343 unsigned long flags; \
346 efi_sync_low_kernel_mappings(); \
347 local_irq_save(flags); \
349 efi_scratch.prev_cr3 = read_cr3(); \
350 write_cr3((unsigned long)efi_scratch.efi_pgt); \
353 func = runtime_service32(f); \
354 __s = efi64_thunk(func, __VA_ARGS__); \
356 write_cr3(efi_scratch.prev_cr3); \
358 local_irq_restore(flags); \
363 efi_status_t efi_thunk_set_virtual_address_map(
364 void *phys_set_virtual_address_map,
365 unsigned long memory_map_size,
366 unsigned long descriptor_size,
367 u32 descriptor_version,
368 efi_memory_desc_t *virtual_map)
374 efi_sync_low_kernel_mappings();
375 local_irq_save(flags);
377 efi_scratch.prev_cr3 = read_cr3();
378 write_cr3((unsigned long)efi_scratch.efi_pgt);
381 func = (u32)(unsigned long)phys_set_virtual_address_map;
382 status = efi64_thunk(func, memory_map_size, descriptor_size,
383 descriptor_version, virtual_map);
385 write_cr3(efi_scratch.prev_cr3);
387 local_irq_restore(flags);
392 static efi_status_t efi_thunk_get_time(efi_time_t *tm, efi_time_cap_t *tc)
395 u32 phys_tm, phys_tc;
397 spin_lock(&rtc_lock);
399 phys_tm = virt_to_phys(tm);
400 phys_tc = virt_to_phys(tc);
402 status = efi_thunk(get_time, phys_tm, phys_tc);
404 spin_unlock(&rtc_lock);
409 static efi_status_t efi_thunk_set_time(efi_time_t *tm)
414 spin_lock(&rtc_lock);
416 phys_tm = virt_to_phys(tm);
418 status = efi_thunk(set_time, phys_tm);
420 spin_unlock(&rtc_lock);
426 efi_thunk_get_wakeup_time(efi_bool_t *enabled, efi_bool_t *pending,
430 u32 phys_enabled, phys_pending, phys_tm;
432 spin_lock(&rtc_lock);
434 phys_enabled = virt_to_phys(enabled);
435 phys_pending = virt_to_phys(pending);
436 phys_tm = virt_to_phys(tm);
438 status = efi_thunk(get_wakeup_time, phys_enabled,
439 phys_pending, phys_tm);
441 spin_unlock(&rtc_lock);
447 efi_thunk_set_wakeup_time(efi_bool_t enabled, efi_time_t *tm)
452 spin_lock(&rtc_lock);
454 phys_tm = virt_to_phys(tm);
456 status = efi_thunk(set_wakeup_time, enabled, phys_tm);
458 spin_unlock(&rtc_lock);
465 efi_thunk_get_variable(efi_char16_t *name, efi_guid_t *vendor,
466 u32 *attr, unsigned long *data_size, void *data)
469 u32 phys_name, phys_vendor, phys_attr;
470 u32 phys_data_size, phys_data;
472 phys_data_size = virt_to_phys(data_size);
473 phys_vendor = virt_to_phys(vendor);
474 phys_name = virt_to_phys(name);
475 phys_attr = virt_to_phys(attr);
476 phys_data = virt_to_phys(data);
478 status = efi_thunk(get_variable, phys_name, phys_vendor,
479 phys_attr, phys_data_size, phys_data);
485 efi_thunk_set_variable(efi_char16_t *name, efi_guid_t *vendor,
486 u32 attr, unsigned long data_size, void *data)
488 u32 phys_name, phys_vendor, phys_data;
491 phys_name = virt_to_phys(name);
492 phys_vendor = virt_to_phys(vendor);
493 phys_data = virt_to_phys(data);
495 /* If data_size is > sizeof(u32) we've got problems */
496 status = efi_thunk(set_variable, phys_name, phys_vendor,
497 attr, data_size, phys_data);
503 efi_thunk_get_next_variable(unsigned long *name_size,
508 u32 phys_name_size, phys_name, phys_vendor;
510 phys_name_size = virt_to_phys(name_size);
511 phys_vendor = virt_to_phys(vendor);
512 phys_name = virt_to_phys(name);
514 status = efi_thunk(get_next_variable, phys_name_size,
515 phys_name, phys_vendor);
521 efi_thunk_get_next_high_mono_count(u32 *count)
526 phys_count = virt_to_phys(count);
527 status = efi_thunk(get_next_high_mono_count, phys_count);
533 efi_thunk_reset_system(int reset_type, efi_status_t status,
534 unsigned long data_size, efi_char16_t *data)
538 phys_data = virt_to_phys(data);
540 efi_thunk(reset_system, reset_type, status, data_size, phys_data);
544 efi_thunk_update_capsule(efi_capsule_header_t **capsules,
545 unsigned long count, unsigned long sg_list)
548 * To properly support this function we would need to repackage
549 * 'capsules' because the firmware doesn't understand 64-bit
552 return EFI_UNSUPPORTED;
556 efi_thunk_query_variable_info(u32 attr, u64 *storage_space,
557 u64 *remaining_space,
558 u64 *max_variable_size)
561 u32 phys_storage, phys_remaining, phys_max;
563 if (efi.runtime_version < EFI_2_00_SYSTEM_TABLE_REVISION)
564 return EFI_UNSUPPORTED;
566 phys_storage = virt_to_phys(storage_space);
567 phys_remaining = virt_to_phys(remaining_space);
568 phys_max = virt_to_phys(max_variable_size);
570 status = efi_thunk(query_variable_info, attr, phys_storage,
571 phys_remaining, phys_max);
577 efi_thunk_query_capsule_caps(efi_capsule_header_t **capsules,
578 unsigned long count, u64 *max_size,
582 * To properly support this function we would need to repackage
583 * 'capsules' because the firmware doesn't understand 64-bit
586 return EFI_UNSUPPORTED;
589 void efi_thunk_runtime_setup(void)
591 efi.get_time = efi_thunk_get_time;
592 efi.set_time = efi_thunk_set_time;
593 efi.get_wakeup_time = efi_thunk_get_wakeup_time;
594 efi.set_wakeup_time = efi_thunk_set_wakeup_time;
595 efi.get_variable = efi_thunk_get_variable;
596 efi.get_next_variable = efi_thunk_get_next_variable;
597 efi.set_variable = efi_thunk_set_variable;
598 efi.get_next_high_mono_count = efi_thunk_get_next_high_mono_count;
599 efi.reset_system = efi_thunk_reset_system;
600 efi.query_variable_info = efi_thunk_query_variable_info;
601 efi.update_capsule = efi_thunk_update_capsule;
602 efi.query_capsule_caps = efi_thunk_query_capsule_caps;
604 #endif /* CONFIG_EFI_MIXED */