diff options
Diffstat (limited to 'arch/x86/boot/edd.c')
| -rw-r--r-- | arch/x86/boot/edd.c | 96 |
1 files changed, 49 insertions, 47 deletions
diff --git a/arch/x86/boot/edd.c b/arch/x86/boot/edd.c index 8721dc46a0b..223e4252707 100644 --- a/arch/x86/boot/edd.c +++ b/arch/x86/boot/edd.c @@ -2,6 +2,7 @@ * * Copyright (C) 1991, 1992 Linus Torvalds * Copyright 2007 rPath, Inc. - All Rights Reserved + * Copyright 2009 Intel Corporation; author H. Peter Anvin * * This file is part of the Linux kernel, and is made available under * the terms of the GNU General Public License version 2. @@ -9,13 +10,12 @@ * ----------------------------------------------------------------------- */ /* - * arch/i386/boot/edd.c - * * Get EDD BIOS disk information */ #include "boot.h" #include <linux/edd.h> +#include "string.h" #if defined(CONFIG_EDD) || defined(CONFIG_EDD_MODULE) @@ -24,17 +24,17 @@ */ static int read_mbr(u8 devno, void *buf) { - u16 ax, bx, cx, dx; + struct biosregs ireg, oreg; + + initregs(&ireg); + ireg.ax = 0x0201; /* Legacy Read, one sector */ + ireg.cx = 0x0001; /* Sector 0-0-1 */ + ireg.dl = devno; + ireg.bx = (size_t)buf; - ax = 0x0201; /* Legacy Read, one sector */ - cx = 0x0001; /* Sector 0-0-1 */ - dx = devno; - bx = (size_t)buf; - asm volatile("pushfl; stc; int $0x13; setc %%al; popfl" - : "+a" (ax), "+c" (cx), "+d" (dx), "+b" (bx) - : : "esi", "edi", "memory"); + intcall(0x13, &ireg, &oreg); - return -(u8)ax; /* 0 or -1 */ + return -(oreg.eflags & X86_EFLAGS_CF); /* 0 or -1 */ } static u32 read_mbr_sig(u8 devno, struct edd_info *ei, u32 *mbrsig) @@ -43,6 +43,7 @@ static u32 read_mbr_sig(u8 devno, struct edd_info *ei, u32 *mbrsig) char *mbrbuf_ptr, *mbrbuf_end; u32 buf_base, mbr_base; extern char _end[]; + u16 mbr_magic; sector_size = ei->params.bytes_per_sector; if (!sector_size) @@ -60,65 +61,59 @@ static u32 read_mbr_sig(u8 devno, struct edd_info *ei, u32 *mbrsig) if (mbrbuf_end > (char *)(size_t)boot_params.hdr.heap_end_ptr) return -1; + memset(mbrbuf_ptr, 0, sector_size); if (read_mbr(devno, mbrbuf_ptr)) return -1; *mbrsig = *(u32 *)&mbrbuf_ptr[EDD_MBR_SIG_OFFSET]; - return 0; + mbr_magic = *(u16 *)&mbrbuf_ptr[510]; + + /* check for valid MBR magic */ + return mbr_magic == 0xAA55 ? 0 : -1; } static int get_edd_info(u8 devno, struct edd_info *ei) { - u16 ax, bx, cx, dx, di; + struct biosregs ireg, oreg; memset(ei, 0, sizeof *ei); /* Check Extensions Present */ - ax = 0x4100; - bx = EDDMAGIC1; - dx = devno; - asm("pushfl; stc; int $0x13; setc %%al; popfl" - : "+a" (ax), "+b" (bx), "=c" (cx), "+d" (dx) - : : "esi", "edi"); + initregs(&ireg); + ireg.ah = 0x41; + ireg.bx = EDDMAGIC1; + ireg.dl = devno; + intcall(0x13, &ireg, &oreg); - if ((u8)ax) + if (oreg.eflags & X86_EFLAGS_CF) return -1; /* No extended information */ - if (bx != EDDMAGIC2) + if (oreg.bx != EDDMAGIC2) return -1; ei->device = devno; - ei->version = ax >> 8; /* EDD version number */ - ei->interface_support = cx; /* EDD functionality subsets */ + ei->version = oreg.ah; /* EDD version number */ + ei->interface_support = oreg.cx; /* EDD functionality subsets */ /* Extended Get Device Parameters */ ei->params.length = sizeof(ei->params); - ax = 0x4800; - dx = devno; - asm("pushfl; int $0x13; popfl" - : "+a" (ax), "+d" (dx), "=m" (ei->params) - : "S" (&ei->params) - : "ebx", "ecx", "edi"); + ireg.ah = 0x48; + ireg.si = (size_t)&ei->params; + intcall(0x13, &ireg, &oreg); /* Get legacy CHS parameters */ /* Ralf Brown recommends setting ES:DI to 0:0 */ - ax = 0x0800; - dx = devno; - di = 0; - asm("pushw %%es; " - "movw %%di,%%es; " - "pushfl; stc; int $0x13; setc %%al; popfl; " - "popw %%es" - : "+a" (ax), "=b" (bx), "=c" (cx), "+d" (dx), "+D" (di) - : : "esi"); - - if ((u8)ax == 0) { - ei->legacy_max_cylinder = (cx >> 8) + ((cx & 0xc0) << 2); - ei->legacy_max_head = dx >> 8; - ei->legacy_sectors_per_track = cx & 0x3f; + ireg.ah = 0x08; + ireg.es = 0; + intcall(0x13, &ireg, &oreg); + + if (!(oreg.eflags & X86_EFLAGS_CF)) { + ei->legacy_max_cylinder = oreg.ch + ((oreg.cl & 0xc0) << 2); + ei->legacy_max_head = oreg.dh; + ei->legacy_sectors_per_track = oreg.cl & 0x3f; } return 0; @@ -128,17 +123,25 @@ void query_edd(void) { char eddarg[8]; int do_mbr = 1; +#ifdef CONFIG_EDD_OFF + int do_edd = 0; +#else int do_edd = 1; +#endif int be_quiet; int devno; struct edd_info ei, *edp; u32 *mbrptr; if (cmdline_find_option("edd", eddarg, sizeof eddarg) > 0) { - if (!strcmp(eddarg, "skipmbr") || !strcmp(eddarg, "skip")) + if (!strcmp(eddarg, "skipmbr") || !strcmp(eddarg, "skip")) { + do_edd = 1; do_mbr = 0; + } else if (!strcmp(eddarg, "off")) do_edd = 0; + else if (!strcmp(eddarg, "on")) + do_edd = 1; } be_quiet = cmdline_find_option_bool("quiet"); @@ -161,9 +164,8 @@ void query_edd(void) * Scan the BIOS-supported hard disks and query EDD * information... */ - get_edd_info(devno, &ei); - - if (boot_params.eddbuf_entries < EDDMAXNR) { + if (!get_edd_info(devno, &ei) + && boot_params.eddbuf_entries < EDDMAXNR) { memcpy(edp, &ei, sizeof ei); edp++; boot_params.eddbuf_entries++; |