From: Ben Gras Date: Mon, 18 Jan 2010 14:10:04 +0000 (+0000) Subject: Fix to make making a bootable cd possible again. X-Git-Tag: v3.1.6~72 X-Git-Url: http://zhaoyanbai.com/repos/%22http:/www.isc.org/icons/zlib_tech.html?a=commitdiff_plain;h=daca9de450d388e8f99d83a8588ae5e3f0411fda;p=minix.git Fix to make making a bootable cd possible again. ow that the image has grown beyond the 1.44M that fits on a floppy. (previously, the floppy emulation mode was used for cd's.) the boot cd now uses 'no emulation mode,' where an image is provided on the cd that is loaded and executed directly. this is the boot monitor. in order to make this work (the entry point is the same as where the image is loaded, and the boot monitor needs its a.out header too) and keep compatability with the same code being used for regular booting, i prepended 16 bytes that jumps over its header so execution can start there. to be able to read the CD (mostly in order to read the boot image), boot has to use the already present 'extended read' call, but address the CD using 2k sectors. --- diff --git a/boot/Makefile b/boot/Makefile index 759fc5d5b..8aa0f3f6e 100644 --- a/boot/Makefile +++ b/boot/Makefile @@ -36,9 +36,16 @@ rawfs86.o: rawfs.c rawfs.o -cmp -s rawfs.o rawfs86.o && ln -f rawfs.o rawfs86.o boot: boothead.s boot.o bootimage.o rawfs86.o - $(LD86) -o $@ \ + $(LD86) -o bootexec \ boothead.s boot.o bootimage.o rawfs86.o $(LIBS) - install -S 8kb boot + install -S 12kb bootexec + # This is code that is executed when used on a bootable + # CD, as its entry point is the start of the file then. + # It jumps over the a.out header into the part of the + # code in boothead.s where the code knows it's booting + # from CD if entered there. + ( printf '\xeb\x3e ' ; cat bootexec ) >boot + chmod 755 boot edparams.o: boot.c ln -f boot.c edparams.c @@ -112,5 +119,5 @@ $(BIN)/edparams: edparams clean: rm -f *.bak *.o - rm -f bootblock addaout installboot boot masterboot jumpboot edparams + rm -f bootblock addaout installboot boot masterboot jumpboot edparams rm -f dosboot boot.com mkfile mkfile.com diff --git a/boot/boot.c b/boot/boot.c index 70fe45254..24dfb52b4 100644 --- a/boot/boot.c +++ b/boot/boot.c @@ -122,6 +122,44 @@ char *bios_err(int err) return "Unknown error"; } +/* CD's are addressed in 2048-byte sectors. + * In order to be able to read CD's but maintain the same interface of 512-byte + * sector addressing, we check if the device is a CD in readsectors() and if so, + * read it into our own buffer first + */ +int readsectors(u32_t bufaddr, u32_t sector, U8_t count) +{ +#define CDSECTOR_SIZE 2048 + static char cdbuf[CDSECTOR_SIZE]; + static i32_t cdbuf_sec = -1; + i32_t cdsec; + + if(device != cddevice) { + return biosreadsectors(bufaddr, sector, count); + } + + while(count > 0) { + u32_t offset; +#define FACTOR (CDSECTOR_SIZE/SECTOR_SIZE) + cdsec = sector / FACTOR; + offset = (sector % FACTOR) * SECTOR_SIZE; + if(cdsec != cdbuf_sec) { + int r; + if((r=biosreadsectors(mon2abs(cdbuf), cdsec, 1)) != 0) { + printf("error %d\n", r); + return r; + } + cdbuf_sec = cdsec; + } + raw_copy(bufaddr, mon2abs(cdbuf) + offset, SECTOR_SIZE); + bufaddr += SECTOR_SIZE; + count--; + sector++; + } + + return 0; +} + char *unix_err(int err) /* Translate the few errors rawfs can give. */ { @@ -515,6 +553,12 @@ void initialize(void) } #endif + /* If we were booted from CD, remember what device it was. */ + if(cdbooted) + cddevice = device; + else + cddevice = 0xff; /* Invalid. */ + /* Set the new caddr for relocate. */ caddr= newaddr; @@ -564,6 +608,14 @@ void initialize(void) readerr(masterpos, r); exit(1); } + /* If we're a CD, we know what we want. */ + if(device == cddevice) { + p = 1; /* We know this is the root FS. */ + lowsec = table[p]->lowsec; + bootdev.primary = p; + break; /* Found! */ + } + /* See if you can find "lowsec" back. */ for (p= 0; p < NR_PARTITIONS; p++) { if (lowsec - table[p]->lowsec < table[p]->size) break; @@ -590,12 +642,17 @@ void initialize(void) bootdev.primary= p; masterpos= table[p]->lowsec; } - strcpy(bootdev.name, "d0p0"); - bootdev.name[1] += (device - 0x80); - bootdev.name[3] += bootdev.primary; - if (bootdev.secondary >= 0) { - strcat(bootdev.name, "s0"); - bootdev.name[5] += bootdev.secondary; + + if(device == cddevice) { + strcpy(bootdev.name, CDNAME); + } else { + strcpy(bootdev.name, "d0p0"); + bootdev.name[1] += (device - 0x80); + bootdev.name[3] += bootdev.primary; + if (bootdev.secondary >= 0) { + strcat(bootdev.name, "s0"); + bootdev.name[5] += bootdev.secondary; + } } /* Find out about the video hardware. */ @@ -1087,7 +1144,7 @@ dev_t name2dev(char *name) n= name; if (strncmp(n, "/dev/", 5) == 0) n+= 5; - if (strcmp(n, "ram") == 0) { + if (strcmp(n, "ram") == 0 || strcmp(n, CDNAME) == 0) { dev= DEV_RAM; } else if (n[0] == 'f' && n[1] == 'd' && numeric(n+2)) { @@ -1879,7 +1936,6 @@ void monitor(void) void boot(void) /* Load Minix and start it, among other things. */ { - /* Initialize tables. */ initialize(); @@ -1928,8 +1984,7 @@ void main(int argc, char **argv) fatal(bootdev.name); /* Check if it is a bootable Minix device. */ - if (readsectors(mon2abs(bootcode), lowsec, 1) != 0 - || memcmp(bootcode, boot_magic, sizeof(boot_magic)) != 0) { + if (readsectors(mon2abs(bootcode), lowsec, 1) != 0) { fprintf(stderr, "edparams: %s: not a bootable Minix device\n", bootdev.name); exit(1); diff --git a/boot/boot.h b/boot/boot.h index 8148f20dc..b651dae1e 100644 --- a/boot/boot.h +++ b/boot/boot.h @@ -58,6 +58,9 @@ EXTERN u32_t caddr, daddr; /* Code and data address of the boot program. */ EXTERN u32_t runsize; /* Size of this program. */ EXTERN u16_t device; /* Drive being booted from. */ +EXTERN u16_t cddevice; /* Drive that is CD if known. */ + +#define CDNAME "cd" /* Name of the CD device. */ typedef struct { /* One chunk of free memory. */ u32_t base; /* Start byte. */ @@ -66,6 +69,7 @@ typedef struct { /* One chunk of free memory. */ EXTERN memory mem[3]; /* List of available memory. */ EXTERN int mon_return; /* Monitor stays in memory? */ +EXTERN int cdbooted; /* Did we boot from CD? (Set by boothead.s.) */ typedef struct bios_env { @@ -101,6 +105,9 @@ int readsectors(u32_t bufaddr, u32_t sector, U8_t count); /* Read 1 or more sectors from "device". */ int writesectors(u32_t bufaddr, u32_t sector, U8_t count); /* Write 1 or more sectors to "device". */ + +int biosreadsectors(u32_t bufaddr, u32_t sector, U8_t count); + int getch(void); /* Read a keypress. */ void scan_keyboard(void); diff --git a/boot/boothead.s b/boot/boothead.s index 5a3bf7d35..8644799ee 100644 --- a/boot/boothead.s +++ b/boot/boothead.s @@ -41,19 +41,30 @@ .extern _rem_part ! To pass partition info .extern _k_flags ! Special kernel flags .extern _mem ! Free memory list +.extern _cdbooted ! Whether we booted from CD +.extern _cddevice ! Whether we booted from CD .text -! Set segment registers and stack pointer using the programs own header! -! The header is either 32 bytes (short form) or 48 bytes (long form). The -! bootblock will jump to address 0x10030 in both cases, calling one of the -! two jmpf instructions below. - - jmpf boot, LOADSEG+3 ! Set cs right (skipping long a.out header) - .space 11 ! jmpf + 11 = 16 bytes - jmpf boot, LOADSEG+2 ! Set cs right (skipping short a.out header) +! We assume boot is always linked with a short (32 byte) a.out header and has +! 16 bytes of its own prefix, so 48 bytes to skip. bootblock jumps into us +! at offset 0x30, cd boot code at 0x40 + + ! Set cs right + ! (skip short a.out header plus 16 byte preefix) + jmpf boot, LOADSEG+3 + .space 11 + + ! entry point when booting from CD + jmpf cdboot, LOADSEG+3 + .space 11 +cdboot: + mov bx, #1 + jmp commonboot boot: - mov ax, #LOADSEG + mov bx, #0 +commonboot: + mov ax, #LOADSEG+1 mov ds, ax ! ds = header movb al, a_flags @@ -96,6 +107,7 @@ sepID: mov _device, dx ! Boot device (probably 0x00 or 0x80) mov _rem_part+0, si ! Remote partition table offset pop _rem_part+2 ! and segment (saved es) + mov _cdbooted, bx ! Booted from CD? (bx set above) ! Remember the current video mode for restoration on exit. movb ah, #0x0F ! Get current video mode @@ -117,7 +129,7 @@ sepID: mov _daddr+0, ax mov _daddr+2, dx push ds - mov ax, #LOADSEG + mov ax, #LOADSEG+1 mov ds, ax ! Back to the header once more mov ax, a_total+0 mov dx, a_total+2 ! dx:ax = data + bss + heap + stack @@ -416,6 +428,8 @@ _dev_open: push es push di ! Save registers used by BIOS calls movb dl, _device ! The default device + cmpb dl, _cddevice + je cdopen cmpb dl, #0x80 ! Floppy < 0x80, winchester >= 0x80 jae winchester floppy: @@ -463,6 +477,10 @@ winchester: jc geoerr ! No such drive? andb cl, #0x3F ! cl = max sector number (1-origin) incb dh ! dh = 1 + max head number (0-origin) + jmp geoboth +cdopen: + movb cl, #0x3F ! Think up geometry for CD's + movb dh, #0x2 geoboth: movb sectors, cl ! Sectors per track movb al, cl ! al = sectors per track @@ -515,20 +533,20 @@ _dev_boundary: neg ax ! ax = (sector % sectors) == 0 ret -! int readsectors(u32_t bufaddr, u32_t sector, u8_t count) +! int biosreadsectors(u32_t bufaddr, u32_t sector, u8_t count) ! int writesectors(u32_t bufaddr, u32_t sector, u8_t count) ! Read/write several sectors from/to disk or floppy. The buffer must ! be between 64K boundaries! Count must fit in a byte. The external ! variables _device, sectors and secspcyl describe the disk and its ! geometry. Returns 0 for success, otherwise the BIOS error code. ! -.define _readsectors, _writesectors +.define _biosreadsectors, _writesectors _writesectors: push bp mov bp, sp movb 13(bp), #0x03 ! Code for a disk write jmp rwsec -_readsectors: +_biosreadsectors: push bp mov bp, sp movb 13(bp), #0x02 ! Code for a disk read @@ -555,6 +573,9 @@ more: mov ax, 8(bp) mov dx, 10(bp) ! dx:ax = abs sector. Divide it by sectors/cyl cmp dx, #[1024*255*63-255]>>16 ! Near 8G limit? jae bigdisk + mov si, _device + cmp si, _cddevice ! Is it a CD? + je bigdisk ! CD's need extended read. div secspcyl ! ax = cylinder, dx = sector within cylinder xchg ax, dx ! ax = sector within cylinder, dx = cylinder movb ch, dl ! ch = low 8 bits of cylinder @@ -1512,5 +1533,3 @@ p_mcs_desc: .comm bus, 2 ! Saved return value of _get_bus .comm unchar, 2 ! Char returned by ungetch(c) .comm line, 2 ! Serial line I/O port to copy console I/O to. - - diff --git a/boot/installboot.c b/boot/installboot.c index 4b8ae4a61..ccaf31dea 100644 --- a/boot/installboot.c +++ b/boot/installboot.c @@ -496,7 +496,8 @@ void make_bootable(enum howto how, char *device, char *bootblock, boothdr.a_magic[0]= !A_MAGIC0; } else { readblock(addr, buf, block_size); - memcpy(&boothdr, buf, sizeof(struct exec)); + /* Must skip 16 bytes of 'boot' as that contains code. */ + memcpy(&boothdr, buf + 16, sizeof(struct exec)); } bootf= nil; dummy.process= boothdr; diff --git a/commands/simple/writeisofs.c b/commands/simple/writeisofs.c index 1274cfe9f..c0816aeee 100644 --- a/commands/simple/writeisofs.c +++ b/commands/simple/writeisofs.c @@ -108,6 +108,7 @@ struct bc_validation { #define INDICATE_BOOTABLE 0x88 +#define BOOTMEDIA_UNSPECIFIED -1 #define BOOTMEDIA_NONE 0 #define BOOTMEDIA_120M 1 #define BOOTMEDIA_144M 2 @@ -160,7 +161,8 @@ struct node { }; int n_reserved_pathtableentries = 0, n_used_pathtableentries = 0; -int harddisk_emulation = 0; +int bootmedia = BOOTMEDIA_UNSPECIFIED; +unsigned long bootseg = 0; int system_type = 0; int get_system_type(int fd); @@ -736,15 +738,17 @@ writebootcatalog(int fd, int *currentsector, int imagesector, int imagesectors) memset(&initial, 0, sizeof(initial)); initial.indicator = INDICATE_BOOTABLE; - if (harddisk_emulation) + initial.media = bootmedia; + initial.seg = (u_int16_t) (bootseg & 0xFFFF); + initial.sectors = 1; + if (bootmedia == BOOTMEDIA_HARDDISK) { - initial.media = BOOTMEDIA_HARDDISK; initial.type = system_type; } - else - initial.media = BOOTMEDIA_144M; - /* initial.sectors = imagesectors; */ - initial.sectors = 1; + if (bootmedia == BOOTMEDIA_NONE) + { + initial.sectors = imagesectors; + } initial.startsector = imagesector; written += Write(fd, &initial, sizeof(initial)); @@ -857,10 +861,24 @@ main(int argc, char *argv[]) return 1; } - while ((ch = getopt(argc, argv, "Rb:hl:")) != -1) { + while ((ch = getopt(argc, argv, "b:s:Rb:hl:nf")) != -1) { switch(ch) { + case 's': + if(optarg[0] != '0' || optarg[1] != 'x') { + fprintf(stderr, "%s: -s\n", + argv[0]); + return 1; + } + bootseg = strtoul(optarg+2, NULL, 16); + break; case 'h': - harddisk_emulation= 1; + bootmedia= BOOTMEDIA_HARDDISK; + break; + case 'n': + bootmedia= BOOTMEDIA_NONE; + break; + case 'f': + bootmedia= BOOTMEDIA_144M; break; case 'l': label = optarg; @@ -881,8 +899,23 @@ main(int argc, char *argv[]) argc -= optind; argv += optind; + /* Args check */ + if(argc != 2) { - fprintf(stderr, "usage: %s [-l