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    Subject[PATCH] Be explicit about what the x86 0x020c boot parameter version requires.
    This should help avoid making the incorrect change in non-compliant

    Signed-off-by: Peter Jones <>
    Documentation/x86/boot.txt | 5 +++--
    arch/x86/include/asm/bootparam_utils.h | 7 +++++++
    2 files changed, 10 insertions(+), 2 deletions(-)

    diff --git a/Documentation/x86/boot.txt b/Documentation/x86/boot.txt
    index 3840b6f..72702db 100644
    --- a/Documentation/x86/boot.txt
    +++ b/Documentation/x86/boot.txt
    @@ -1110,7 +1110,8 @@ firmware, 'table' is the EFI system table - these are the first two
    arguments of the "handoff state" as described in section 2.3 of the
    UEFI specification. 'bp' is the boot loader-allocated boot params.

    -The boot loader *must* fill out the following fields in bp,
    +The boot loader *must* zero the entirity of bp, and then fill out the
    +following fields:

    o hdr.code32_start
    o hdr.cmd_line_ptr
    @@ -1118,4 +1119,4 @@ The boot loader *must* fill out the following fields in bp,
    o hdr.ramdisk_image (if applicable)
    o hdr.ramdisk_size (if applicable)

    -All other fields should be zero.
    +All other fields should remain zero.
    diff --git a/arch/x86/include/asm/bootparam_utils.h b/arch/x86/include/asm/bootparam_utils.h
    index 5b5e9cb..b4e8aa8 100644
    --- a/arch/x86/include/asm/bootparam_utils.h
    +++ b/arch/x86/include/asm/bootparam_utils.h
    @@ -17,6 +17,13 @@
    static void sanitize_boot_params(struct boot_params *boot_params)
    + /* Note: do not simply clear this field. The purpose of this field is
    + * to guarantee compliance with the x86 boot spec located in
    + * Documentation/x86/boot.txt . That spec says that the *whole*
    + * structure should be cleared. If you're having an issue because
    + * the sentinel is set, you need to change the whole structure to be
    + * cleared, not this (or any other) indidivual field.
    + */
    if (boot_params->sentinel) {
    /*fields in boot_params are not valid, clear them */
    memset(&boot_params->olpc_ofw_header, 0,

     \ /
      Last update: 2013-03-06 19:41    [W:18.736 / U:0.016 seconds]
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