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    Subject[PATCH 4.10 31/69] efi/libstub: Skip GOP with PIXEL_BLT_ONLY format
    Date
    4.10-stable review patch.  If anyone has any objections, please let me know.

    ------------------

    From: Cohen, Eugene <eugene@hp.com>

    commit 540f4c0e894f7e46a66dfa424b16424cbdc12c38 upstream.

    The UEFI Specification permits Graphics Output Protocol (GOP) instances
    without direct framebuffer access. This is indicated in the Mode structure
    with a PixelFormat enumeration value of PIXEL_BLT_ONLY. Given that the
    kernel does not know how to drive a Blt() only framebuffer (which is only
    permitted before ExitBootServices() anyway), we should disregard such
    framebuffers when looking for a GOP instance that is suitable for use as
    the boot console.

    So modify the EFI GOP initialization to not use a PIXEL_BLT_ONLY instance,
    preventing attempts later in boot to use an invalid screen_info.lfb_base
    address.

    Signed-off-by: Eugene Cohen <eugene@hp.com>
    [ Moved the Blt() only check into the loop and clarified that Blt() only GOPs are unusable by the kernel. ]
    Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
    Cc: Linus Torvalds <torvalds@linux-foundation.org>
    Cc: Matt Fleming <matt@codeblueprint.co.uk>
    Cc: Peter Zijlstra <peterz@infradead.org>
    Cc: Thomas Gleixner <tglx@linutronix.de>
    Cc: leif.lindholm@linaro.org
    Cc: linux-efi@vger.kernel.org
    Cc: lorenzo.pieralisi@arm.com
    Fixes: 9822504c1fa5 ("efifb: Enable the efi-framebuffer platform driver ...")
    Link: http://lkml.kernel.org/r/20170404152744.26687-2-ard.biesheuvel@linaro.org
    Signed-off-by: Ingo Molnar <mingo@kernel.org>
    Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

    ---
    drivers/firmware/efi/libstub/gop.c | 6 ++++--
    1 file changed, 4 insertions(+), 2 deletions(-)

    --- a/drivers/firmware/efi/libstub/gop.c
    +++ b/drivers/firmware/efi/libstub/gop.c
    @@ -149,7 +149,8 @@ setup_gop32(efi_system_table_t *sys_tabl

    status = __gop_query32(sys_table_arg, gop32, &info, &size,
    &current_fb_base);
    - if (status == EFI_SUCCESS && (!first_gop || conout_found)) {
    + if (status == EFI_SUCCESS && (!first_gop || conout_found) &&
    + info->pixel_format != PIXEL_BLT_ONLY) {
    /*
    * Systems that use the UEFI Console Splitter may
    * provide multiple GOP devices, not all of which are
    @@ -266,7 +267,8 @@ setup_gop64(efi_system_table_t *sys_tabl

    status = __gop_query64(sys_table_arg, gop64, &info, &size,
    &current_fb_base);
    - if (status == EFI_SUCCESS && (!first_gop || conout_found)) {
    + if (status == EFI_SUCCESS && (!first_gop || conout_found) &&
    + info->pixel_format != PIXEL_BLT_ONLY) {
    /*
    * Systems that use the UEFI Console Splitter may
    * provide multiple GOP devices, not all of which are

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