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    Subject[PATCH 1/9] update boot spec to 2.07
    Proposed updates for version 2.07 of the boot protocol.  This includes:

    load_flags.KEEP_SEGMENTS- flag to request/inhibit segment reloads
    hardware_subarch - what subarchitecture we're booting under
    hardware_subarch_data - per-architecture data

    The intention of these changes is to make booting a paravirtualized
    kernel work via the normal Linux boot protocol. The intention is that
    the bzImage payload can be a properly formed ELF file, so that the
    bootloader can use its ELF notes and Phdrs to get more metadata about
    the kernel and its requirements.

    The ELF file could be the uncompressed kernel vmlinux itself; it would
    only take small buildsystem changes to implement this.

    Signed-off-by: Jeremy Fitzhardinge <jeremy@xensource.com>
    Cc: "Eric W. Biederman" <ebiederm@xmission.com>
    Cc: H. Peter Anvin <hpa@zytor.com>
    Cc: Vivek Goyal <vgoyal@in.ibm.com>
    Cc: Rusty Russell <rusty@rustcorp.com.au>

    ---
    Documentation/i386/boot.txt | 34 +++++++++++++++++++++++++++++++++-
    arch/i386/kernel/asm-offsets.c | 7 +++++++
    include/asm-i386/bootparam.h | 9 +++++++--
    3 files changed, 47 insertions(+), 3 deletions(-)

    ===================================================================
    --- a/Documentation/i386/boot.txt
    +++ b/Documentation/i386/boot.txt
    @@ -168,6 +168,8 @@ 0234/1 2.05+ relocatable_kernel Whether
    0234/1 2.05+ relocatable_kernel Whether kernel is relocatable or not
    0235/3 N/A pad2 Unused
    0238/4 2.06+ cmdline_size Maximum size of the kernel command line
    +023C/4 2.07+ hardware_subarch Hardware subarchitecture
    +0240/8 2.07+ hardware_subarch_data Subarchitecture-specific data

    (1) For backwards compatibility, if the setup_sects field contains 0, the
    real value is 4.
    @@ -204,7 +206,7 @@ boot loaders can ignore those fields.

    The byte order of all fields is littleendian (this is x86, after all.)

    -Field name: setup_secs
    +Field name: setup_sects
    Type: read
    Offset/size: 0x1f1/1
    Protocol: ALL
    @@ -356,6 +358,13 @@ Protocol: 2.00+
    - If 0, the protected-mode code is loaded at 0x10000.
    - If 1, the protected-mode code is loaded at 0x100000.

    + Bit 6 (write): KEEP_SEGMENTS
    + Protocol: 2.07+
    + - if 0, reload the segment registers in the 32bit entry point.
    + - if 1, do not reload the segment registers in the 32bit entry point.
    + Assume that %cs %ds %ss %es are all set to flat segments with
    + a base of 0 (or the equivalent for their environment).
    +
    Bit 7 (write): CAN_USE_HEAP
    Set this bit to 1 to indicate that the value entered in the
    heap_end_ptr is valid. If this field is clear, some setup code
    @@ -479,6 +488,29 @@ Protocol: 2.06+
    zero. This means that the command line can contain at most
    cmdline_size characters. With protocol version 2.05 and earlier, the
    maximum size was 255.
    +
    +Field name: hardware_subarch
    +Type: write
    +Offset/size: 0x23c/4
    +Protocol: 2.07+
    +
    + In a paravirtualized environment the hardware low level architectural
    + pieces such as interrupt handling, page table handling, and
    + accessing process control registers needs to be done differently.
    +
    + This field allows the bootloader to inform the kernel we are in one
    + one of those environments.
    +
    + 0x00000000 The default x86/PC environment
    + 0x00000001 lguest
    + 0x00000002 Xen
    +
    +Field name: hardware_subarch_data
    +Type: write
    +Offset/size: 0x240/8
    +Protocol: 2.07+
    +
    + A pointer to data that is specific to hardware subarch


    **** THE KERNEL COMMAND LINE
    ===================================================================
    --- a/arch/i386/kernel/asm-offsets.c
    +++ b/arch/i386/kernel/asm-offsets.c
    @@ -15,6 +15,7 @@
    #include <asm/fixmap.h>
    #include <asm/processor.h>
    #include <asm/thread_info.h>
    +#include <asm/bootparam.h>
    #include <asm/elf.h>
    #include <xen/interface/xen.h>

    @@ -143,4 +144,10 @@ void foo(void)
    OFFSET(LGUEST_PAGES_regs_errcode, lguest_pages, regs.errcode);
    OFFSET(LGUEST_PAGES_regs, lguest_pages, regs);
    #endif
    +
    + BLANK();
    + OFFSET(BP_scratch, boot_params, scratch);
    + OFFSET(BP_loadflags, boot_params, hdr.loadflags);
    + OFFSET(BP_hardware_subarch, boot_params, hdr.hardware_subarch);
    + OFFSET(BP_version, boot_params, hdr.version);
    }
    ===================================================================
    --- a/include/asm-i386/bootparam.h
    +++ b/include/asm-i386/bootparam.h
    @@ -24,8 +24,9 @@ struct setup_header {
    u16 kernel_version;
    u8 type_of_loader;
    u8 loadflags;
    -#define LOADED_HIGH 0x01
    -#define CAN_USE_HEAP 0x80
    +#define LOADED_HIGH (1<<0)
    +#define KEEP_SEGMENTS (1<<6)
    +#define CAN_USE_HEAP (1<<7)
    u16 setup_move_size;
    u32 code32_start;
    u32 ramdisk_image;
    @@ -37,6 +38,10 @@ struct setup_header {
    u32 initrd_addr_max;
    u32 kernel_alignment;
    u8 relocatable_kernel;
    + u8 _pad2[3];
    + u32 cmdline_size;
    + u32 hardware_subarch;
    + u64 hardware_subarch_data;
    } __attribute__((packed));

    struct sys_desc_table {
    --

    -
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