• Konrad Rzeszutek Wilk's avatar
    x86, gdt, hibernate: Store/load GDT for hibernate path. · cc456c4e
    Konrad Rzeszutek Wilk authored
    The git commite7a5cd06
    ("x86-64, gdt: Store/load GDT for ACPI S3 or hibernate/resume path
    is not needed.") assumes that for the hibernate path the booting
    kernel and the resuming kernel MUST be the same. That is certainly
    the case for a 32-bit kernel (see check_image_kernel and
    CONFIG_ARCH_HIBERNATION_HEADER config option).
    
    However for 64-bit kernels it is OK to have a different kernel
    version (and size of the image) of the booting and resuming kernels.
    Hence the above mentioned git commit introduces an regression.
    
    This patch fixes it by introducing a 'struct desc_ptr gdt_desc'
    back in the 'struct saved_context'. However instead of having in the
    'save_processor_state' and 'restore_processor_state' the
    store/load_gdt calls, we are only saving the GDT in the
    save_processor_state.
    
    For the restore path the lgdt operation is done in
    hibernate_asm_[32|64].S in the 'restore_registers' path.
    
    The apt reader of this description will recognize that only 64-bit
    kernels need this treatment, not 32-bit. This patch adds the logic
    in the 32-bit path to be more similar to 64-bit so that in the future
    the unification process can take advantage of this.
    
    [ hpa: this also reverts an inadvertent on-disk format change ]
    Suggested-by: default avatar"H. Peter Anvin" <hpa@zytor.com>
    Acked-by: default avatar"Rafael J. Wysocki" <rjw@sisk.pl>
    Signed-off-by: default avatarKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>
    Link: http://lkml.kernel.org/r/1367459610-9656-2-git-send-email-konrad.wilk@oracle.comSigned-off-by: default avatarH. Peter Anvin <hpa@linux.intel.com>
    cc456c4e
hibernate_asm_32.S 1.68 KB