xref: /openbmc/linux/arch/x86/platform/efi/efi_64.c (revision e23feb16)
1 /*
2  * x86_64 specific EFI support functions
3  * Based on Extensible Firmware Interface Specification version 1.0
4  *
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>
10  *
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.
14  * - mouli 06/14/2007.
15  *
16  */
17 
18 #include <linux/kernel.h>
19 #include <linux/init.h>
20 #include <linux/mm.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>
28 #include <linux/io.h>
29 #include <linux/reboot.h>
30 #include <linux/slab.h>
31 
32 #include <asm/setup.h>
33 #include <asm/page.h>
34 #include <asm/e820.h>
35 #include <asm/pgtable.h>
36 #include <asm/tlbflush.h>
37 #include <asm/proto.h>
38 #include <asm/efi.h>
39 #include <asm/cacheflush.h>
40 #include <asm/fixmap.h>
41 
42 static pgd_t *save_pgd __initdata;
43 static unsigned long efi_flags __initdata;
44 
45 static void __init early_code_mapping_set_exec(int executable)
46 {
47 	efi_memory_desc_t *md;
48 	void *p;
49 
50 	if (!(__supported_pte_mask & _PAGE_NX))
51 		return;
52 
53 	/* Make EFI service code area executable */
54 	for (p = memmap.map; p < memmap.map_end; p += memmap.desc_size) {
55 		md = p;
56 		if (md->type == EFI_RUNTIME_SERVICES_CODE ||
57 		    md->type == EFI_BOOT_SERVICES_CODE)
58 			efi_set_executable(md, executable);
59 	}
60 }
61 
62 void __init efi_call_phys_prelog(void)
63 {
64 	unsigned long vaddress;
65 	int pgd;
66 	int n_pgds;
67 
68 	early_code_mapping_set_exec(1);
69 	local_irq_save(efi_flags);
70 
71 	n_pgds = DIV_ROUND_UP((max_pfn << PAGE_SHIFT), PGDIR_SIZE);
72 	save_pgd = kmalloc(n_pgds * sizeof(pgd_t), GFP_KERNEL);
73 
74 	for (pgd = 0; pgd < n_pgds; pgd++) {
75 		save_pgd[pgd] = *pgd_offset_k(pgd * PGDIR_SIZE);
76 		vaddress = (unsigned long)__va(pgd * PGDIR_SIZE);
77 		set_pgd(pgd_offset_k(pgd * PGDIR_SIZE), *pgd_offset_k(vaddress));
78 	}
79 	__flush_tlb_all();
80 }
81 
82 void __init efi_call_phys_epilog(void)
83 {
84 	/*
85 	 * After the lock is released, the original page table is restored.
86 	 */
87 	int pgd;
88 	int n_pgds = DIV_ROUND_UP((max_pfn << PAGE_SHIFT) , PGDIR_SIZE);
89 	for (pgd = 0; pgd < n_pgds; pgd++)
90 		set_pgd(pgd_offset_k(pgd * PGDIR_SIZE), save_pgd[pgd]);
91 	kfree(save_pgd);
92 	__flush_tlb_all();
93 	local_irq_restore(efi_flags);
94 	early_code_mapping_set_exec(0);
95 }
96 
97 void __iomem *__init efi_ioremap(unsigned long phys_addr, unsigned long size,
98 				 u32 type, u64 attribute)
99 {
100 	unsigned long last_map_pfn;
101 
102 	if (type == EFI_MEMORY_MAPPED_IO)
103 		return ioremap(phys_addr, size);
104 
105 	last_map_pfn = init_memory_mapping(phys_addr, phys_addr + size);
106 	if ((last_map_pfn << PAGE_SHIFT) < phys_addr + size) {
107 		unsigned long top = last_map_pfn << PAGE_SHIFT;
108 		efi_ioremap(top, size - (top - phys_addr), type, attribute);
109 	}
110 
111 	if (!(attribute & EFI_MEMORY_WB))
112 		efi_memory_uc((u64)(unsigned long)__va(phys_addr), size);
113 
114 	return (void __iomem *)__va(phys_addr);
115 }
116