From 6e7a315eb67cb6c113cf37e1d66c4f11a51a2b3e Mon Sep 17 00:00:00 2001 From: Daniel Baumann Date: Sun, 7 Apr 2024 18:29:51 +0200 Subject: Adding upstream version 2.06. Signed-off-by: Daniel Baumann --- grub-core/disk/i386/pc/biosdisk.c | 688 ++++++++++++++++++++++++++++++++++++++ 1 file changed, 688 insertions(+) create mode 100644 grub-core/disk/i386/pc/biosdisk.c (limited to 'grub-core/disk/i386/pc/biosdisk.c') diff --git a/grub-core/disk/i386/pc/biosdisk.c b/grub-core/disk/i386/pc/biosdisk.c new file mode 100644 index 0000000..8ca250c --- /dev/null +++ b/grub-core/disk/i386/pc/biosdisk.c @@ -0,0 +1,688 @@ +/* + * GRUB -- GRand Unified Bootloader + * Copyright (C) 1999,2000,2001,2002,2003,2004,2005,2006,2007,2008,2009,2010 Free Software Foundation, Inc. + * + * GRUB is free software: you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation, either version 3 of the License, or + * (at your option) any later version. + * + * GRUB is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with GRUB. If not, see . + */ + +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +GRUB_MOD_LICENSE ("GPLv3+"); + +static int cd_drive = 0; +static int grub_biosdisk_rw_int13_extensions (int ah, int drive, void *dap); + +static int grub_biosdisk_get_num_floppies (void) +{ + struct grub_bios_int_registers regs; + int drive; + + /* reset the disk system first */ + regs.eax = 0; + regs.edx = 0; + regs.flags = GRUB_CPU_INT_FLAGS_DEFAULT; + + grub_bios_interrupt (0x13, ®s); + + for (drive = 0; drive < 2; drive++) + { + regs.flags = GRUB_CPU_INT_FLAGS_DEFAULT | GRUB_CPU_INT_FLAGS_CARRY; + regs.edx = drive; + + /* call GET DISK TYPE */ + regs.eax = 0x1500; + grub_bios_interrupt (0x13, ®s); + if (regs.flags & GRUB_CPU_INT_FLAGS_CARRY) + break; + + /* check if this drive exists */ + if (!(regs.eax & 0x300)) + break; + } + + return drive; +} + +/* + * Call IBM/MS INT13 Extensions (int 13 %ah=AH) for DRIVE. DAP + * is passed for disk address packet. If an error occurs, return + * non-zero, otherwise zero. + */ + +static int +grub_biosdisk_rw_int13_extensions (int ah, int drive, void *dap) +{ + struct grub_bios_int_registers regs; + regs.eax = ah << 8; + /* compute the address of disk_address_packet */ + regs.ds = (((grub_addr_t) dap) & 0xffff0000) >> 4; + regs.esi = (((grub_addr_t) dap) & 0xffff); + regs.edx = drive; + regs.flags = GRUB_CPU_INT_FLAGS_DEFAULT; + + grub_bios_interrupt (0x13, ®s); + return (regs.eax >> 8) & 0xff; +} + +/* + * Call standard and old INT13 (int 13 %ah=AH) for DRIVE. Read/write + * NSEC sectors from COFF/HOFF/SOFF into SEGMENT. If an error occurs, + * return non-zero, otherwise zero. + */ +static int +grub_biosdisk_rw_standard (int ah, int drive, int coff, int hoff, + int soff, int nsec, int segment) +{ + int ret, i; + + /* Try 3 times. */ + for (i = 0; i < 3; i++) + { + struct grub_bios_int_registers regs; + + /* set up CHS information */ + /* set %ch to low eight bits of cylinder */ + regs.ecx = (coff << 8) & 0xff00; + /* set bits 6-7 of %cl to high two bits of cylinder */ + regs.ecx |= (coff >> 2) & 0xc0; + /* set bits 0-5 of %cl to sector */ + regs.ecx |= soff & 0x3f; + + /* set %dh to head and %dl to drive */ + regs.edx = (drive & 0xff) | ((hoff << 8) & 0xff00); + /* set %ah to AH */ + regs.eax = (ah << 8) & 0xff00; + /* set %al to NSEC */ + regs.eax |= nsec & 0xff; + + regs.ebx = 0; + regs.es = segment; + + regs.flags = GRUB_CPU_INT_FLAGS_DEFAULT; + + grub_bios_interrupt (0x13, ®s); + /* check if successful */ + if (!(regs.flags & GRUB_CPU_INT_FLAGS_CARRY)) + return 0; + + /* save return value */ + ret = regs.eax >> 8; + + /* if fail, reset the disk system */ + regs.eax = 0; + regs.edx = (drive & 0xff); + regs.flags = GRUB_CPU_INT_FLAGS_DEFAULT; + grub_bios_interrupt (0x13, ®s); + } + return ret; +} + +/* + * Check if LBA is supported for DRIVE. If it is supported, then return + * the major version of extensions, otherwise zero. + */ +static int +grub_biosdisk_check_int13_extensions (int drive) +{ + struct grub_bios_int_registers regs; + + regs.edx = drive & 0xff; + regs.eax = 0x4100; + regs.ebx = 0x55aa; + regs.flags = GRUB_CPU_INT_FLAGS_DEFAULT; + grub_bios_interrupt (0x13, ®s); + + if (regs.flags & GRUB_CPU_INT_FLAGS_CARRY) + return 0; + + if ((regs.ebx & 0xffff) != 0xaa55) + return 0; + + /* check if AH=0x42 is supported */ + if (!(regs.ecx & 1)) + return 0; + + return (regs.eax >> 8) & 0xff; +} + +/* + * Return the geometry of DRIVE in CYLINDERS, HEADS and SECTORS. If an + * error occurs, then return non-zero, otherwise zero. + */ +static int +grub_biosdisk_get_diskinfo_standard (int drive, + unsigned long *cylinders, + unsigned long *heads, + unsigned long *sectors) +{ + struct grub_bios_int_registers regs; + + regs.eax = 0x0800; + regs.edx = drive & 0xff; + + regs.flags = GRUB_CPU_INT_FLAGS_DEFAULT; + grub_bios_interrupt (0x13, ®s); + + /* Check if unsuccessful. Ignore return value if carry isn't set to + workaround some buggy BIOSes. */ + if ((regs.flags & GRUB_CPU_INT_FLAGS_CARRY) && ((regs.eax & 0xff00) != 0)) + return (regs.eax & 0xff00) >> 8; + + /* bogus BIOSes may not return an error number */ + /* 0 sectors means no disk */ + if (!(regs.ecx & 0x3f)) + /* XXX 0x60 is one of the unused error numbers */ + return 0x60; + + /* the number of heads is counted from zero */ + *heads = ((regs.edx >> 8) & 0xff) + 1; + *cylinders = (((regs.ecx >> 8) & 0xff) | ((regs.ecx << 2) & 0x0300)) + 1; + *sectors = regs.ecx & 0x3f; + return 0; +} + +static int +grub_biosdisk_get_diskinfo_real (int drive, void *drp, grub_uint16_t ax) +{ + struct grub_bios_int_registers regs; + + regs.eax = ax; + + /* compute the address of drive parameters */ + regs.esi = ((grub_addr_t) drp) & 0xf; + regs.ds = ((grub_addr_t) drp) >> 4; + regs.edx = drive & 0xff; + + regs.flags = GRUB_CPU_INT_FLAGS_DEFAULT; + grub_bios_interrupt (0x13, ®s); + + /* Check if unsuccessful. Ignore return value if carry isn't set to + workaround some buggy BIOSes. */ + if ((regs.flags & GRUB_CPU_INT_FLAGS_CARRY) && ((regs.eax & 0xff00) != 0)) + return (regs.eax & 0xff00) >> 8; + + return 0; +} + +/* + * Return the cdrom information of DRIVE in CDRP. If an error occurs, + * then return non-zero, otherwise zero. + */ +static int +grub_biosdisk_get_cdinfo_int13_extensions (int drive, void *cdrp) +{ + return grub_biosdisk_get_diskinfo_real (drive, cdrp, 0x4b01); +} + +/* + * Return the geometry of DRIVE in a drive parameters, DRP. If an error + * occurs, then return non-zero, otherwise zero. + */ +static int +grub_biosdisk_get_diskinfo_int13_extensions (int drive, void *drp) +{ + return grub_biosdisk_get_diskinfo_real (drive, drp, 0x4800); +} + +static int +grub_biosdisk_get_drive (const char *name) +{ + unsigned long drive; + + if (name[0] == 'c' && name[1] == 'd' && name[2] == 0 && cd_drive) + return cd_drive; + + if ((name[0] != 'f' && name[0] != 'h') || name[1] != 'd') + goto fail; + + drive = grub_strtoul (name + 2, 0, 10); + if (grub_errno != GRUB_ERR_NONE) + goto fail; + + if (name[0] == 'h') + drive += 0x80; + + return (int) drive ; + + fail: + grub_error (GRUB_ERR_UNKNOWN_DEVICE, "not a biosdisk"); + return -1; +} + +static int +grub_biosdisk_call_hook (grub_disk_dev_iterate_hook_t hook, void *hook_data, + int drive) +{ + char name[10]; + + if (cd_drive && drive == cd_drive) + return hook ("cd", hook_data); + + grub_snprintf (name, sizeof (name), + (drive & 0x80) ? "hd%d" : "fd%d", drive & (~0x80)); + return hook (name, hook_data); +} + +static int +grub_biosdisk_iterate (grub_disk_dev_iterate_hook_t hook, void *hook_data, + grub_disk_pull_t pull) +{ + int num_floppies; + int drive; + + /* For hard disks, attempt to read the MBR. */ + switch (pull) + { + case GRUB_DISK_PULL_NONE: + for (drive = 0x80; drive < 0x90; drive++) + { + if (grub_biosdisk_rw_standard (0x02, drive, 0, 0, 1, 1, + GRUB_MEMORY_MACHINE_SCRATCH_SEG) != 0) + { + grub_dprintf ("disk", "Read error when probing drive 0x%2x\n", drive); + break; + } + + if (grub_biosdisk_call_hook (hook, hook_data, drive)) + return 1; + } + return 0; + + case GRUB_DISK_PULL_REMOVABLE: + if (cd_drive) + { + if (grub_biosdisk_call_hook (hook, hook_data, cd_drive)) + return 1; + } + + /* For floppy disks, we can get the number safely. */ + num_floppies = grub_biosdisk_get_num_floppies (); + for (drive = 0; drive < num_floppies; drive++) + if (grub_biosdisk_call_hook (hook, hook_data, drive)) + return 1; + return 0; + default: + return 0; + } + return 0; +} + +static grub_err_t +grub_biosdisk_open (const char *name, grub_disk_t disk) +{ + grub_uint64_t total_sectors = 0; + int drive; + struct grub_biosdisk_data *data; + + drive = grub_biosdisk_get_drive (name); + if (drive < 0) + return grub_errno; + + disk->id = drive; + + data = (struct grub_biosdisk_data *) grub_zalloc (sizeof (*data)); + if (! data) + return grub_errno; + + data->drive = drive; + + if ((cd_drive) && (drive == cd_drive)) + { + data->flags = GRUB_BIOSDISK_FLAG_LBA | GRUB_BIOSDISK_FLAG_CDROM; + data->sectors = 8; + disk->log_sector_size = 11; + /* TODO: get the correct size. */ + total_sectors = GRUB_DISK_SIZE_UNKNOWN; + } + else + { + /* HDD */ + int version; + + disk->log_sector_size = 9; + + version = grub_biosdisk_check_int13_extensions (drive); + if (version) + { + struct grub_biosdisk_drp *drp + = (struct grub_biosdisk_drp *) GRUB_MEMORY_MACHINE_SCRATCH_ADDR; + + /* Clear out the DRP. */ + grub_memset (drp, 0, sizeof (*drp)); + drp->size = sizeof (*drp); + if (! grub_biosdisk_get_diskinfo_int13_extensions (drive, drp)) + { + data->flags = GRUB_BIOSDISK_FLAG_LBA; + + if (drp->total_sectors) + total_sectors = drp->total_sectors; + else + /* Some buggy BIOSes doesn't return the total sectors + correctly but returns zero. So if it is zero, compute + it by C/H/S returned by the LBA BIOS call. */ + total_sectors = ((grub_uint64_t) drp->cylinders) + * drp->heads * drp->sectors; + if (drp->bytes_per_sector + && !(drp->bytes_per_sector & (drp->bytes_per_sector - 1)) + && drp->bytes_per_sector >= 512 + && drp->bytes_per_sector <= 16384) + { + for (disk->log_sector_size = 0; + (1 << disk->log_sector_size) < drp->bytes_per_sector; + disk->log_sector_size++); + } + } + } + } + + if (! (data->flags & GRUB_BIOSDISK_FLAG_CDROM)) + { + if (grub_biosdisk_get_diskinfo_standard (drive, + &data->cylinders, + &data->heads, + &data->sectors) != 0) + { + if (total_sectors && (data->flags & GRUB_BIOSDISK_FLAG_LBA)) + { + data->sectors = 63; + data->heads = 255; + data->cylinders + = grub_divmod64 (total_sectors + + data->heads * data->sectors - 1, + data->heads * data->sectors, 0); + } + else + { + grub_free (data); + return grub_error (GRUB_ERR_BAD_DEVICE, "%s cannot get C/H/S values", disk->name); + } + } + + if (data->sectors == 0) + data->sectors = 63; + if (data->heads == 0) + data->heads = 255; + + if (! total_sectors) + total_sectors = ((grub_uint64_t) data->cylinders) + * data->heads * data->sectors; + } + + disk->total_sectors = total_sectors; + /* Limit the max to 0x7f because of Phoenix EDD. */ + disk->max_agglomerate = 0x7f >> GRUB_DISK_CACHE_BITS; + COMPILE_TIME_ASSERT ((0x7f >> GRUB_DISK_CACHE_BITS + << (GRUB_DISK_SECTOR_BITS + GRUB_DISK_CACHE_BITS)) + + sizeof (struct grub_biosdisk_dap) + < GRUB_MEMORY_MACHINE_SCRATCH_SIZE); + + disk->data = data; + + return GRUB_ERR_NONE; +} + +static void +grub_biosdisk_close (grub_disk_t disk) +{ + grub_free (disk->data); +} + +/* For readability. */ +#define GRUB_BIOSDISK_READ 0 +#define GRUB_BIOSDISK_WRITE 1 + +#define GRUB_BIOSDISK_CDROM_RETRY_COUNT 3 + +static grub_err_t +grub_biosdisk_rw (int cmd, grub_disk_t disk, + grub_disk_addr_t sector, grub_size_t size, + unsigned segment) +{ + struct grub_biosdisk_data *data = disk->data; + + /* VirtualBox fails with sectors above 2T on CDs. + Since even BD-ROMS are never that big anyway, return error. */ + if ((data->flags & GRUB_BIOSDISK_FLAG_CDROM) + && (sector >> 32)) + return grub_error (GRUB_ERR_OUT_OF_RANGE, + N_("attempt to read or write outside of disk `%s'"), + disk->name); + + if (data->flags & GRUB_BIOSDISK_FLAG_LBA) + { + struct grub_biosdisk_dap *dap; + + dap = (struct grub_biosdisk_dap *) (GRUB_MEMORY_MACHINE_SCRATCH_ADDR + + (data->sectors + << disk->log_sector_size)); + dap->length = sizeof (*dap); + dap->reserved = 0; + dap->blocks = size; + dap->buffer = segment << 16; /* The format SEGMENT:ADDRESS. */ + dap->block = sector; + + if (data->flags & GRUB_BIOSDISK_FLAG_CDROM) + { + int i; + + if (cmd) + return grub_error (GRUB_ERR_WRITE_ERROR, N_("cannot write to CD-ROM")); + + for (i = 0; i < GRUB_BIOSDISK_CDROM_RETRY_COUNT; i++) + if (! grub_biosdisk_rw_int13_extensions (0x42, data->drive, dap)) + break; + + if (i == GRUB_BIOSDISK_CDROM_RETRY_COUNT) + return grub_error (GRUB_ERR_READ_ERROR, N_("failure reading sector 0x%llx " + "from `%s'"), + (unsigned long long) sector, + disk->name); + } + else + if (grub_biosdisk_rw_int13_extensions (cmd + 0x42, data->drive, dap)) + { + /* Fall back to the CHS mode. */ + data->flags &= ~GRUB_BIOSDISK_FLAG_LBA; + disk->total_sectors = data->cylinders * data->heads * data->sectors; + return grub_biosdisk_rw (cmd, disk, sector, size, segment); + } + } + else + { + unsigned coff, hoff, soff; + unsigned head; + + /* It is impossible to reach over 8064 MiB (a bit less than LBA24) with + the traditional CHS access. */ + if (sector > + 1024 /* cylinders */ * + 256 /* heads */ * + 63 /* spt */) + return grub_error (GRUB_ERR_OUT_OF_RANGE, + N_("attempt to read or write outside of disk `%s'"), + disk->name); + + soff = ((grub_uint32_t) sector) % data->sectors + 1; + head = ((grub_uint32_t) sector) / data->sectors; + hoff = head % data->heads; + coff = head / data->heads; + + if (coff >= data->cylinders) + return grub_error (GRUB_ERR_OUT_OF_RANGE, + N_("attempt to read or write outside of disk `%s'"), + disk->name); + + if (grub_biosdisk_rw_standard (cmd + 0x02, data->drive, + coff, hoff, soff, size, segment)) + { + switch (cmd) + { + case GRUB_BIOSDISK_READ: + return grub_error (GRUB_ERR_READ_ERROR, N_("failure reading sector 0x%llx " + "from `%s'"), + (unsigned long long) sector, + disk->name); + case GRUB_BIOSDISK_WRITE: + return grub_error (GRUB_ERR_WRITE_ERROR, N_("failure writing sector 0x%llx " + "to `%s'"), + (unsigned long long) sector, + disk->name); + } + } + } + + return GRUB_ERR_NONE; +} + +/* Return the number of sectors which can be read safely at a time. */ +static grub_size_t +get_safe_sectors (grub_disk_t disk, grub_disk_addr_t sector) +{ + grub_size_t size; + grub_uint64_t offset; + struct grub_biosdisk_data *data = disk->data; + grub_uint32_t sectors = data->sectors; + + /* OFFSET = SECTOR % SECTORS */ + grub_divmod64 (sector, sectors, &offset); + + size = sectors - offset; + + return size; +} + +static grub_err_t +grub_biosdisk_read (grub_disk_t disk, grub_disk_addr_t sector, + grub_size_t size, char *buf) +{ + while (size) + { + grub_size_t len; + + len = get_safe_sectors (disk, sector); + + if (len > size) + len = size; + + if (grub_biosdisk_rw (GRUB_BIOSDISK_READ, disk, sector, len, + GRUB_MEMORY_MACHINE_SCRATCH_SEG)) + return grub_errno; + + grub_memcpy (buf, (void *) GRUB_MEMORY_MACHINE_SCRATCH_ADDR, + len << disk->log_sector_size); + + buf += len << disk->log_sector_size; + sector += len; + size -= len; + } + + return grub_errno; +} + +static grub_err_t +grub_biosdisk_write (grub_disk_t disk, grub_disk_addr_t sector, + grub_size_t size, const char *buf) +{ + struct grub_biosdisk_data *data = disk->data; + + if (data->flags & GRUB_BIOSDISK_FLAG_CDROM) + return grub_error (GRUB_ERR_IO, N_("cannot write to CD-ROM")); + + while (size) + { + grub_size_t len; + + len = get_safe_sectors (disk, sector); + if (len > size) + len = size; + + grub_memcpy ((void *) GRUB_MEMORY_MACHINE_SCRATCH_ADDR, buf, + len << disk->log_sector_size); + + if (grub_biosdisk_rw (GRUB_BIOSDISK_WRITE, disk, sector, len, + GRUB_MEMORY_MACHINE_SCRATCH_SEG)) + return grub_errno; + + buf += len << disk->log_sector_size; + sector += len; + size -= len; + } + + return grub_errno; +} + +static struct grub_disk_dev grub_biosdisk_dev = + { + .name = "biosdisk", + .id = GRUB_DISK_DEVICE_BIOSDISK_ID, + .disk_iterate = grub_biosdisk_iterate, + .disk_open = grub_biosdisk_open, + .disk_close = grub_biosdisk_close, + .disk_read = grub_biosdisk_read, + .disk_write = grub_biosdisk_write, + .next = 0 + }; + +static void +grub_disk_biosdisk_fini (void) +{ + grub_disk_dev_unregister (&grub_biosdisk_dev); +} + +GRUB_MOD_INIT(biosdisk) +{ + struct grub_biosdisk_cdrp *cdrp + = (struct grub_biosdisk_cdrp *) GRUB_MEMORY_MACHINE_SCRATCH_ADDR; + grub_uint8_t boot_drive; + + if (grub_disk_firmware_is_tainted) + { + grub_puts_ (N_("Native disk drivers are in use. " + "Refusing to use firmware disk interface.")); + return; + } + grub_disk_firmware_fini = grub_disk_biosdisk_fini; + + grub_memset (cdrp, 0, sizeof (*cdrp)); + cdrp->size = sizeof (*cdrp); + cdrp->media_type = 0xFF; + boot_drive = (grub_boot_device >> 24); + if ((! grub_biosdisk_get_cdinfo_int13_extensions (boot_drive, cdrp)) + && ((cdrp->media_type & GRUB_BIOSDISK_CDTYPE_MASK) + == GRUB_BIOSDISK_CDTYPE_NO_EMUL)) + cd_drive = cdrp->drive_no; + /* Since diskboot.S rejects devices over 0x90 it must be a CD booted with + cdboot.S + */ + if (boot_drive >= 0x90) + cd_drive = boot_drive; + + grub_disk_dev_register (&grub_biosdisk_dev); +} + +GRUB_MOD_FINI(biosdisk) +{ + grub_disk_biosdisk_fini (); +} -- cgit v1.2.3