diff -urN stock3/linux-2.5.3-pre1/Documentation/i386/boot.txt linux-2.5.3-pre1/Documentation/i386/boot.txt --- stock3/linux-2.5.3-pre1/Documentation/i386/boot.txt Wed Nov 7 14:46:01 2001 +++ linux-2.5.3-pre1/Documentation/i386/boot.txt Tue Jan 15 14:14:32 2002 @@ -2,7 +2,7 @@ ---------------------------- H. Peter Anvin - Last update 2000-10-29 + Last update 2002-01-01 On the i386 platform, the Linux kernel uses a rather complicated boot convention. This has evolved partially due to historical aspects, as @@ -25,12 +25,15 @@ Protocol 2.01: (Kernel 1.3.76) Added a heap overrun warning. Protocol 2.02: (Kernel 2.4.0-test3-pre3) New command line protocol. - Lower the conventional memory ceiling. No overwrite + Lower the conventional memory ceiling. No overwrite of the traditional setup area, thus making booting safe for systems which use the EBDA from SMM or 32-bit BIOS entry points. zImage deprecated but still supported. +Protocol 2.03: (Kernel 2.4.18-pre1) Explicitly makes the highest possible + initrd address available to the bootloader. + **** MEMORY LAYOUT @@ -45,7 +48,7 @@ 098000 +------------------------+ | Kernel setup | The kernel real-mode code. 090200 +------------------------+ - | Kernel boot sector | The kernel legacy boot sector. + | Kernel boot sector | The kernel legacy boot sector. 090000 +------------------------+ | Protected-mode kernel | The bulk of the kernel image. 010000 +------------------------+ @@ -62,16 +65,16 @@ When using bzImage, the protected-mode kernel was relocated to 0x100000 ("high memory"), and the kernel real-mode block (boot sector, setup, and stack/heap) was made relocatable to any address between -0x10000 and end of low memory. Unfortunately, in protocols 2.00 and +0x10000 and end of low memory. Unfortunately, in protocols 2.00 and 2.01 the command line is still required to live in the 0x9XXXX memory range, and that memory range is still overwritten by the early kernel. -The 2.02 protocol fixes that. +The 2.02 protocol resolves that problem. It is desirable to keep the "memory ceiling" -- the highest point in low memory touched by the boot loader -- as low as possible, since some newer BIOSes have begun to allocate some rather large amounts of memory, called the Extended BIOS Data Area, near the top of low -memory. The boot loader should use the "INT 12h" BIOS call to verify +memory. The boot loader should use the "INT 12h" BIOS call to verify how much low memory is available. Unfortunately, if INT 12h reports that the amount of memory is too @@ -112,7 +115,8 @@ 0202/4 2.00+ header Magic signature "HdrS" 0206/2 2.00+ version Boot protocol version supported 0208/4 2.00+ realmode_swtch Boot loader hook (see below) -020C/4 2.00+ start_sys Points to kernel version string +020C/2 2.00+ start_sys The load-low segment (0x1000) (obsolete) +020E/2 2.00+ kernel_version Pointer to kernel version string 0210/1 2.00+ type_of_loader Boot loader identifier 0211/1 2.00+ loadflags Boot protocol option flags 0212/2 2.00+ setup_move_size Move to high memory size (used with hooks) @@ -123,6 +127,7 @@ 0224/2 2.01+ heap_end_ptr Free memory after setup end 0226/2 N/A pad1 Unused 0228/4 2.02+ cmd_line_ptr 32-bit pointer to the kernel command line +022C/4 2.03+ initrd_addr_max Highest legal initrd address For backwards compatibility, if the setup_sects field contains 0, the real value is 4. @@ -140,6 +145,15 @@ setting fields in the header, you must make sure only to set fields supported by the protocol version in use. +The "kernel_version" field, if set to a nonzero value, contains a +pointer to a null-terminated human-readable kernel version number +string, less 0x200. This can be used to display the kernel version to +the user. This value should be less than (0x200*setup_sects). For +example, if this value is set to 0x1c00, the kernel version number +string can be found at offset 0x1e00 in the kernel file. This is a +valid value if and only if the "setup_sects" field contains the value +14 or higher. + Most boot loaders will simply load the kernel at its target address directly. Such boot loaders do not need to worry about filling in most of the fields in the header. The following fields should be @@ -160,6 +174,9 @@ 3 SYSLINUX 4 EtherBoot + Please contact if you need a bootloader ID + value assigned. + loadflags, heap_end_ptr: If the protocol version is 2.01 or higher, enter the offset limit of the setup heap into heap_end_ptr and set the @@ -180,9 +197,9 @@ The initrd should typically be located as high in memory as possible, as it may otherwise get overwritten by the early - kernel initialization sequence. However, it must never be - located above address 0x3C000000 if you want all kernels to - read it. + kernel initialization sequence. However, it must never be + located above the address specified in the initrd_addr_max + field. The initrd should be at least 4K page aligned. cmd_line_ptr: If the protocol version is 2.02 or higher, this is a 32-bit @@ -192,7 +209,15 @@ command line, in which case you can point this to an empty string (or better yet, to the string "auto".) If this field is left at zero, the kernel will assume that your boot loader - does not support the 2.02 protocol. + does not support the 2.02+ protocol. + + ramdisk_max: + The maximum address that may be occupied by the initrd + contents. For boot protocols 2.02 or earlier, this field is + not present, and the maximum address is 0x37FFFFFF. (This + address is defined as the address of the highest safe byte, so + if your ramdisk is exactly 131072 bytes long and this field is + 0x37FFFFFF, you can start your ramdisk at 0x37FE0000.) **** THE KERNEL COMMAND LINE @@ -254,14 +279,14 @@ if ( protocol >= 0x0202 ) { cmd_line_ptr = base_ptr + 0x9000; } else { - cmd_line_magic = 0xA33F; + cmd_line_magic = 0xA33F; cmd_line_offset = 0x9000; setup_move_size = 0x9100; } } else { /* Very old kernel */ - cmd_line_magic = 0xA33F; + cmd_line_magic = 0xA33F; cmd_line_offset = 0x9000; /* A very old kernel MUST have its real-mode code @@ -411,4 +436,3 @@ After completing your hook, you should jump to the address that was in this field before your boot loader overwrote it. - diff -urN stock3/linux-2.5.3-pre1/arch/i386/boot/setup.S linux-2.5.3-pre1/arch/i386/boot/setup.S --- stock3/linux-2.5.3-pre1/arch/i386/boot/setup.S Wed Nov 28 10:24:33 2001 +++ linux-2.5.3-pre1/arch/i386/boot/setup.S Tue Jan 15 14:21:15 2002 @@ -50,7 +50,8 @@ #include #include #include - +#include + /* Signature words to ensure LILO loaded us right */ #define SIG1 0xAA55 #define SIG2 0x5A5A @@ -79,7 +80,7 @@ # This is the setup header, and it must start at %cs:2 (old 0x9020:2) .ascii "HdrS" # header signature - .word 0x0202 # header version number (>= 0x0105) + .word 0x0203 # header version number (>= 0x0105) # or else old loadlin-1.5 will fail) realmode_swtch: .word 0, 0 # default_switch, SETUPSEG start_sys_seg: .word SYSSEG @@ -152,6 +153,10 @@ # 0x90000 segment; the setup # can be located anywhere in # low memory 0x10000 or higher. + +ramdisk_max: .long __MAXMEM-1 # (Header version 0x0203 or later) + # The highest safe address for + # the contents of an initrd trampoline: call start_of_setup .space 1024 diff -urN stock3/linux-2.5.3-pre1/arch/i386/kernel/setup.c linux-2.5.3-pre1/arch/i386/kernel/setup.c --- stock3/linux-2.5.3-pre1/arch/i386/kernel/setup.c Fri Jan 11 16:24:36 2002 +++ linux-2.5.3-pre1/arch/i386/kernel/setup.c Tue Jan 15 14:06:23 2002 @@ -704,10 +704,8 @@ #define PFN_PHYS(x) ((x) << PAGE_SHIFT) /* - * 128MB for vmalloc and initrd + * Reserved space for vmalloc and iomap - defined in asm/page.h */ -#define VMALLOC_RESERVE (unsigned long)(128 << 20) -#define MAXMEM (unsigned long)(-PAGE_OFFSET-VMALLOC_RESERVE) #define MAXMEM_PFN PFN_DOWN(MAXMEM) #define MAX_NONPAE_PFN (1 << 20) diff -urN stock3/linux-2.5.3-pre1/include/asm-i386/page.h linux-2.5.3-pre1/include/asm-i386/page.h --- stock3/linux-2.5.3-pre1/include/asm-i386/page.h Mon Jan 14 13:27:06 2002 +++ linux-2.5.3-pre1/include/asm-i386/page.h Tue Jan 15 14:06:23 2002 @@ -80,6 +80,12 @@ #define __PAGE_OFFSET (0xC0000000) +/* + * This much address space is reserved for vmalloc() and iomap() + * as well as fixmap mappings. + */ +#define __VMALLOC_RESERVE (128 << 20) + #ifndef __ASSEMBLY__ /* @@ -118,6 +124,9 @@ #endif /* __ASSEMBLY__ */ #define PAGE_OFFSET ((unsigned long)__PAGE_OFFSET) +#define VMALLOC_RESERVE ((unsigned long)__VMALLOC_RESERVE) +#define __MAXMEM (-__PAGE_OFFSET-__VMALLOC_RESERVE) +#define MAXMEM ((unsigned long)(-PAGE_OFFSET-VMALLOC_RESERVE)) #define __pa(x) ((unsigned long)(x)-PAGE_OFFSET) #define __va(x) ((void *)((unsigned long)(x)+PAGE_OFFSET)) #define virt_to_page(kaddr) (mem_map + (__pa(kaddr) >> PAGE_SHIFT))