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1da177e4 LT |
1 | /* |
2 | * Extensible Firmware Interface | |
3 | * | |
4 | * Based on Extensible Firmware Interface Specification version 1.0 | |
5 | * | |
6 | * Copyright (C) 1999 VA Linux Systems | |
7 | * Copyright (C) 1999 Walt Drummond <drummond@valinux.com> | |
8 | * Copyright (C) 1999-2002 Hewlett-Packard Co. | |
9 | * David Mosberger-Tang <davidm@hpl.hp.com> | |
10 | * Stephane Eranian <eranian@hpl.hp.com> | |
11 | * | |
12 | * All EFI Runtime Services are not implemented yet as EFI only | |
13 | * supports physical mode addressing on SoftSDV. This is to be fixed | |
14 | * in a future version. --drummond 1999-07-20 | |
15 | * | |
16 | * Implemented EFI runtime services and virtual mode calls. --davidm | |
17 | * | |
18 | * Goutham Rao: <goutham.rao@intel.com> | |
19 | * Skip non-WB memory and ignore empty memory ranges. | |
20 | */ | |
21 | ||
1da177e4 | 22 | #include <linux/kernel.h> |
1da177e4 | 23 | #include <linux/types.h> |
1da177e4 | 24 | #include <linux/ioport.h> |
1da177e4 LT |
25 | #include <linux/efi.h> |
26 | ||
1da177e4 LT |
27 | #include <asm/io.h> |
28 | #include <asm/page.h> | |
29 | #include <asm/pgtable.h> | |
1da177e4 | 30 | #include <asm/tlbflush.h> |
cc7e73f3 | 31 | #include <asm/efi.h> |
1da177e4 | 32 | |
1da177e4 LT |
33 | /* |
34 | * To make EFI call EFI runtime service in physical addressing mode we need | |
35 | * prelog/epilog before/after the invocation to disable interrupt, to | |
36 | * claim EFI runtime service handler exclusively and to duplicate a memory in | |
37 | * low memory space say 0 - 3G. | |
38 | */ | |
39 | ||
40 | static unsigned long efi_rt_eflags; | |
1da177e4 LT |
41 | static pgd_t efi_bak_pg_dir_pointer[2]; |
42 | ||
8b2cb7a8 | 43 | void efi_call_phys_prelog(void) |
1da177e4 LT |
44 | { |
45 | unsigned long cr4; | |
46 | unsigned long temp; | |
6b68f01b | 47 | struct desc_ptr gdt_descr; |
1da177e4 | 48 | |
1da177e4 LT |
49 | local_irq_save(efi_rt_eflags); |
50 | ||
51 | /* | |
52 | * If I don't have PSE, I should just duplicate two entries in page | |
53 | * directory. If I have PSE, I just need to duplicate one entry in | |
54 | * page directory. | |
55 | */ | |
4bb0d3ec | 56 | cr4 = read_cr4(); |
1da177e4 LT |
57 | |
58 | if (cr4 & X86_CR4_PSE) { | |
59 | efi_bak_pg_dir_pointer[0].pgd = | |
60 | swapper_pg_dir[pgd_index(0)].pgd; | |
61 | swapper_pg_dir[0].pgd = | |
62 | swapper_pg_dir[pgd_index(PAGE_OFFSET)].pgd; | |
63 | } else { | |
64 | efi_bak_pg_dir_pointer[0].pgd = | |
65 | swapper_pg_dir[pgd_index(0)].pgd; | |
66 | efi_bak_pg_dir_pointer[1].pgd = | |
67 | swapper_pg_dir[pgd_index(0x400000)].pgd; | |
68 | swapper_pg_dir[pgd_index(0)].pgd = | |
69 | swapper_pg_dir[pgd_index(PAGE_OFFSET)].pgd; | |
70 | temp = PAGE_OFFSET + 0x400000; | |
71 | swapper_pg_dir[pgd_index(0x400000)].pgd = | |
72 | swapper_pg_dir[pgd_index(temp)].pgd; | |
73 | } | |
74 | ||
75 | /* | |
76 | * After the lock is released, the original page table is restored. | |
77 | */ | |
8b2cb7a8 | 78 | __flush_tlb_all(); |
1da177e4 | 79 | |
4fbb5968 RR |
80 | gdt_descr.address = __pa(get_cpu_gdt_table(0)); |
81 | gdt_descr.size = GDT_SIZE - 1; | |
82 | load_gdt(&gdt_descr); | |
1da177e4 LT |
83 | } |
84 | ||
8b2cb7a8 | 85 | void efi_call_phys_epilog(void) |
1da177e4 LT |
86 | { |
87 | unsigned long cr4; | |
6b68f01b | 88 | struct desc_ptr gdt_descr; |
1da177e4 | 89 | |
4fbb5968 RR |
90 | gdt_descr.address = (unsigned long)get_cpu_gdt_table(0); |
91 | gdt_descr.size = GDT_SIZE - 1; | |
92 | load_gdt(&gdt_descr); | |
2b932f6c | 93 | |
4bb0d3ec | 94 | cr4 = read_cr4(); |
1da177e4 LT |
95 | |
96 | if (cr4 & X86_CR4_PSE) { | |
97 | swapper_pg_dir[pgd_index(0)].pgd = | |
98 | efi_bak_pg_dir_pointer[0].pgd; | |
99 | } else { | |
100 | swapper_pg_dir[pgd_index(0)].pgd = | |
101 | efi_bak_pg_dir_pointer[0].pgd; | |
102 | swapper_pg_dir[pgd_index(0x400000)].pgd = | |
103 | efi_bak_pg_dir_pointer[1].pgd; | |
104 | } | |
105 | ||
106 | /* | |
107 | * After the lock is released, the original page table is restored. | |
108 | */ | |
8b2cb7a8 | 109 | __flush_tlb_all(); |
1da177e4 LT |
110 | |
111 | local_irq_restore(efi_rt_eflags); | |
1da177e4 | 112 | } |