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-rw-r--r--arch/x86/boot/edd.c71
1 files changed, 31 insertions, 40 deletions
diff --git a/arch/x86/boot/edd.c b/arch/x86/boot/edd.c
index 1aae8f3e5ca1..c501a5b466f8 100644
--- a/arch/x86/boot/edd.c
+++ b/arch/x86/boot/edd.c
@@ -2,6 +2,7 @@
2 * 2 *
3 * Copyright (C) 1991, 1992 Linus Torvalds 3 * Copyright (C) 1991, 1992 Linus Torvalds
4 * Copyright 2007 rPath, Inc. - All Rights Reserved 4 * Copyright 2007 rPath, Inc. - All Rights Reserved
5 * Copyright 2009 Intel Corporation; author H. Peter Anvin
5 * 6 *
6 * This file is part of the Linux kernel, and is made available under 7 * This file is part of the Linux kernel, and is made available under
7 * the terms of the GNU General Public License version 2. 8 * the terms of the GNU General Public License version 2.
@@ -22,17 +23,17 @@
22 */ 23 */
23static int read_mbr(u8 devno, void *buf) 24static int read_mbr(u8 devno, void *buf)
24{ 25{
25 u16 ax, bx, cx, dx; 26 struct biosregs ireg, oreg;
26 27
27 ax = 0x0201; /* Legacy Read, one sector */ 28 initregs(&ireg);
28 cx = 0x0001; /* Sector 0-0-1 */ 29 ireg.ax = 0x0201; /* Legacy Read, one sector */
29 dx = devno; 30 ireg.cx = 0x0001; /* Sector 0-0-1 */
30 bx = (size_t)buf; 31 ireg.dl = devno;
31 asm volatile("pushfl; stc; int $0x13; setc %%al; popfl" 32 ireg.bx = (size_t)buf;
32 : "+a" (ax), "+c" (cx), "+d" (dx), "+b" (bx)
33 : : "esi", "edi", "memory");
34 33
35 return -(u8)ax; /* 0 or -1 */ 34 intcall(0x13, &ireg, &oreg);
35
36 return -(oreg.eflags & X86_EFLAGS_CF); /* 0 or -1 */
36} 37}
37 38
38static u32 read_mbr_sig(u8 devno, struct edd_info *ei, u32 *mbrsig) 39static u32 read_mbr_sig(u8 devno, struct edd_info *ei, u32 *mbrsig)
@@ -72,56 +73,46 @@ static u32 read_mbr_sig(u8 devno, struct edd_info *ei, u32 *mbrsig)
72 73
73static int get_edd_info(u8 devno, struct edd_info *ei) 74static int get_edd_info(u8 devno, struct edd_info *ei)
74{ 75{
75 u16 ax, bx, cx, dx, di; 76 struct biosregs ireg, oreg;
76 77
77 memset(ei, 0, sizeof *ei); 78 memset(ei, 0, sizeof *ei);
78 79
79 /* Check Extensions Present */ 80 /* Check Extensions Present */
80 81
81 ax = 0x4100; 82 initregs(&ireg);
82 bx = EDDMAGIC1; 83 ireg.ah = 0x41;
83 dx = devno; 84 ireg.bx = EDDMAGIC1;
84 asm("pushfl; stc; int $0x13; setc %%al; popfl" 85 ireg.dl = devno;
85 : "+a" (ax), "+b" (bx), "=c" (cx), "+d" (dx) 86 intcall(0x13, &ireg, &oreg);
86 : : "esi", "edi");
87 87
88 if ((u8)ax) 88 if (oreg.eflags & X86_EFLAGS_CF)
89 return -1; /* No extended information */ 89 return -1; /* No extended information */
90 90
91 if (bx != EDDMAGIC2) 91 if (oreg.bx != EDDMAGIC2)
92 return -1; 92 return -1;
93 93
94 ei->device = devno; 94 ei->device = devno;
95 ei->version = ax >> 8; /* EDD version number */ 95 ei->version = oreg.ah; /* EDD version number */
96 ei->interface_support = cx; /* EDD functionality subsets */ 96 ei->interface_support = oreg.cx; /* EDD functionality subsets */
97 97
98 /* Extended Get Device Parameters */ 98 /* Extended Get Device Parameters */
99 99
100 ei->params.length = sizeof(ei->params); 100 ei->params.length = sizeof(ei->params);
101 ax = 0x4800; 101 ireg.ah = 0x48;
102 dx = devno; 102 ireg.si = (size_t)&ei->params;
103 asm("pushfl; int $0x13; popfl" 103 intcall(0x13, &ireg, &oreg);
104 : "+a" (ax), "+d" (dx), "=m" (ei->params)
105 : "S" (&ei->params)
106 : "ebx", "ecx", "edi");
107 104
108 /* Get legacy CHS parameters */ 105 /* Get legacy CHS parameters */
109 106
110 /* Ralf Brown recommends setting ES:DI to 0:0 */ 107 /* Ralf Brown recommends setting ES:DI to 0:0 */
111 ax = 0x0800; 108 ireg.ah = 0x08;
112 dx = devno; 109 ireg.es = 0;
113 di = 0; 110 intcall(0x13, &ireg, &oreg);
114 asm("pushw %%es; " 111
115 "movw %%di,%%es; " 112 if (!(oreg.eflags & X86_EFLAGS_CF)) {
116 "pushfl; stc; int $0x13; setc %%al; popfl; " 113 ei->legacy_max_cylinder = oreg.ch + ((oreg.cl & 0xc0) << 2);
117 "popw %%es" 114 ei->legacy_max_head = oreg.dh;
118 : "+a" (ax), "=b" (bx), "=c" (cx), "+d" (dx), "+D" (di) 115 ei->legacy_sectors_per_track = oreg.cl & 0x3f;
119 : : "esi");
120
121 if ((u8)ax == 0) {
122 ei->legacy_max_cylinder = (cx >> 8) + ((cx & 0xc0) << 2);
123 ei->legacy_max_head = dx >> 8;
124 ei->legacy_sectors_per_track = cx & 0x3f;
125 } 116 }
126 117
127 return 0; 118 return 0;