The EFI Graphics Output Protocol can return a 64-bit linear frame buffer address in some firmware/BIOS implementations. We currently only store the lower 32-bits in the lfb_base. This will eventually be passed to Linux kernel and the efifb driver will incorrectly interpret the framebuffer address as 32-bit address.
The Linux kernel has already added support to handle 64-bit linear framebuffer address in the efifb driver since quite some time now. This patch adds the support for 64-bit linear frame buffer address in GRUB to address the above mentioned scenario. Signed-off-by: Arindam Nath <arindam.n...@amd.com> --- grub-core/loader/i386/linux.c | 2 ++ include/grub/i386/linux.h | 5 ++++- 2 files changed, 6 insertions(+), 1 deletion(-) diff --git a/grub-core/loader/i386/linux.c b/grub-core/loader/i386/linux.c index 083f9417c..1644e8132 100644 --- a/grub-core/loader/i386/linux.c +++ b/grub-core/loader/i386/linux.c @@ -306,6 +306,8 @@ grub_linux_setup_video (struct linux_kernel_params *params) params->lfb_line_len = mode_info.pitch; params->lfb_base = (grub_size_t) framebuffer; + params->ext_lfb_base = (grub_size_t) (((grub_uint64_t)(grub_size_t) framebuffer) >> 32); + params->capabilities |= VIDEO_CAPABILITY_64BIT_BASE; params->lfb_size = ALIGN_UP (params->lfb_line_len * params->lfb_height, 65536); params->red_mask_size = mode_info.red_mask_size; diff --git a/include/grub/i386/linux.h b/include/grub/i386/linux.h index da0ca3b83..e3f91e7c0 100644 --- a/include/grub/i386/linux.h +++ b/include/grub/i386/linux.h @@ -188,8 +188,11 @@ struct linux_kernel_params grub_uint16_t lfb_pages; /* 32 */ grub_uint16_t vesa_attrib; /* 34 */ grub_uint32_t capabilities; /* 36 */ +#define VIDEO_CAPABILITY_SKIP_QUIRKS (1 << 0) +#define VIDEO_CAPABILITY_64BIT_BASE (1 << 1) /* Frame buffer base is 64-bit */ + grub_uint32_t ext_lfb_base; /* 3a */ - grub_uint8_t padding3[0x40 - 0x3a]; + grub_uint8_t padding3[0x40 - 0x3e]; grub_uint16_t apm_version; /* 40 */ grub_uint16_t apm_code_segment; /* 42 */ -- 2.17.1 _______________________________________________ Grub-devel mailing list Grub-devel@gnu.org https://lists.gnu.org/mailman/listinfo/grub-devel
