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linux_trampoline: Handle coreboot framebuffer 

Translate the coreboot framebuffer info from coreboot tables to
the Linux zero page.

Tested in QEMU/Q35 with a kernel w/ efifb enabled.

Change-Id: I2447b2366df8dd8ffe741c943de544d8b4d02dff
Signed-off-by: Nico Huber <nico.h@gmx.de>
Co-authored-by: Bill XIE <persmule@hardenedlinux.org>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/76431
Reviewed-by: Paul Menzel <paulepanter@mailbox.org>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Tim Wawrzynczak <inforichland@gmail.com>
Reviewed-by: Samuel Holland <samuel@sholland.org>
Reviewed-by: Bill XIE <persmule@hardenedlinux.org>
This commit is contained in:
Nico Huber 2023-07-14 14:20:39 +02:00 committed by Felix Held
parent d1b8589583
commit 295f6bf8d4
2 changed files with 43 additions and 9 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

31
util/cbfstool/linux_trampoline.S
View File

@ -102,7 +102,36 @@ jmp .endScan
.testFramebuffer:
cmp $CB_TAG_FRAMEBUFFER, (%ebx)
jne .endScan
/* TODO: handle framebuffer tag */
cmpl $0, 0x0c(%ebx) /* check if upper 32-bit of framebuffer address are 0 */
jne .endScan
mov $LINUX_PARAM_LOC, %edi /* translate the framebuffer entry into Linux' struct screen_info */
mov 0x08(%ebx), %eax /* physical_address */
mov %eax, 0x18(%edi) /* -> lfb_base */
mov 0x10(%ebx), %eax /* x_resolution */
mov %ax, 0x12(%edi) /* -> lfb_width */
mov 0x14(%ebx), %eax /* y_resolution */
mov %ax, 0x14(%edi) /* -> lfb_height */
mov 0x18(%ebx), %edx /* bytes_per_line */
mov %dx, 0x24(%edi) /* -> lfb_linelength */
mul %edx /* bytes_per_line * y_resolution */
mov %eax, 0x1c(%edi) /* -> lfb_size */
movzbw 0x1c(%ebx), %ax /* bits_per_pixel */
mov %ax, 0x16(%edi) /* -> lfb_depth */
mov $4, %esi /* Copy 4 color components' pos and size, each 1 byte. */
1:
mov 0x1b(%ebx, %esi, 2), %ax
rol %ax /* Order is reversed for Linux, hence swap. */
mov %ax, 0x24(%edi, %esi, 2)
dec %esi
jnz 1b
#define LFB_EFI_SIMPLE 0x70 /* VIDEO_TYPE_EFI in Linux */
movb $LFB_EFI_SIMPLE, 0x0f(%edi) /* -> orig_video_isVGA */
.endScan:
add 4(%ebx), %ebx

21
util/cbfstool/linux_trampoline.c
View File

@ -3,18 +3,23 @@
unsigned char trampoline[] = {
0xfc, 0x31, 0xd2, 0xb9, 0x00, 0x00, 0x00, 0x00, 0xbb, 0x00, 0x00, 0x01, 0x00, 0x01, 0xcb, 0x8b,
0x01, 0x3d, 0x4c, 0x42, 0x49, 0x4f, 0x74, 0x07, 0x83, 0xc1, 0x10, 0x39, 0xcb, 0x75, 0xe9, 0x39,
0xcb, 0x0f, 0x84, 0xc5, 0x00, 0x00, 0x00, 0x8b, 0x59, 0x04, 0x01, 0xcb, 0x8b, 0x49, 0x14, 0x83,
0xcb, 0x0f, 0x84, 0x12, 0x01, 0x00, 0x00, 0x8b, 0x59, 0x04, 0x01, 0xcb, 0x8b, 0x49, 0x14, 0x83,
0x3b, 0x11, 0x75, 0x05, 0x8b, 0x4b, 0x08, 0xeb, 0xcf, 0x83, 0x3b, 0x01, 0x75, 0x53, 0x8b, 0x43,
0x04, 0x83, 0xe8, 0x08, 0xc1, 0xe8, 0x02, 0x3d, 0xa0, 0x00, 0x00, 0x00, 0x7e, 0x05, 0xb8, 0xa0,
0x00, 0x00, 0x00, 0x89, 0xc6, 0xbf, 0x05, 0x00, 0x00, 0x00, 0xf7, 0xf7, 0xa3, 0xe8, 0x01, 0x09,
0x00, 0x89, 0xf0, 0x91, 0x8d, 0x73, 0x08, 0xbf, 0xd0, 0x02, 0x09, 0x00, 0xf3, 0xa5, 0x91, 0xa1,
0xe8, 0x01, 0x09, 0x00, 0xbf, 0xd0, 0x02, 0x09, 0x00, 0x83, 0xf8, 0x00, 0x74, 0x2f, 0x83, 0x7f,
0xe8, 0x01, 0x09, 0x00, 0xbf, 0xd0, 0x02, 0x09, 0x00, 0x83, 0xf8, 0x00, 0x74, 0x7c, 0x83, 0x7f,
0x10, 0x0c, 0x7e, 0x07, 0xc7, 0x47, 0x10, 0x02, 0x00, 0x00, 0x00, 0x48, 0x83, 0xc7, 0x14, 0xeb,
0xe8, 0x83, 0x3b, 0x43, 0x75, 0x12, 0x8b, 0x43, 0x08, 0xa3, 0x70, 0x00, 0x09, 0x00, 0x8b, 0x43,
0x0c, 0xa3, 0x74, 0x00, 0x09, 0x00, 0xeb, 0x05, 0x83, 0x3b, 0x12, 0x75, 0x00, 0x03, 0x5b, 0x04,
0x49, 0x0f, 0x85, 0x78, 0xff, 0xff, 0xff, 0xb8, 0x00, 0x00, 0x04, 0x00, 0xc7, 0x40, 0x10, 0xff,
0xff, 0x00, 0x00, 0xc7, 0x40, 0x14, 0x00, 0x9b, 0xcf, 0x00, 0xc7, 0x40, 0x18, 0xff, 0xff, 0x00,
0x00, 0xc7, 0x40, 0x1c, 0x00, 0x93, 0xcf, 0x00, 0xc6, 0x00, 0x2b, 0x89, 0x40, 0x02, 0x0f, 0x01,
0x10, 0xbe, 0x00, 0x00, 0x09, 0x00, 0xff, 0x25, 0x14, 0x02, 0x09, 0x00, 0xf4, 0xeb, 0xfd
0x0c, 0xa3, 0x74, 0x00, 0x09, 0x00, 0xeb, 0x52, 0x83, 0x3b, 0x12, 0x75, 0x4d, 0x83, 0x7b, 0x0c,
0x00, 0x75, 0x47, 0xbf, 0x00, 0x00, 0x09, 0x00, 0x8b, 0x43, 0x08, 0x89, 0x47, 0x18, 0x8b, 0x43,
0x10, 0x66, 0x89, 0x47, 0x12, 0x8b, 0x43, 0x14, 0x66, 0x89, 0x47, 0x14, 0x8b, 0x53, 0x18, 0x66,
0x89, 0x57, 0x24, 0xf7, 0xe2, 0x89, 0x47, 0x1c, 0x66, 0x0f, 0xb6, 0x43, 0x1c, 0x66, 0x89, 0x47,
0x16, 0xbe, 0x04, 0x00, 0x00, 0x00, 0x66, 0x8b, 0x44, 0x73, 0x1b, 0x66, 0xd1, 0xc0, 0x66, 0x89,
0x44, 0x77, 0x24, 0x4e, 0x75, 0xf0, 0xc6, 0x47, 0x0f, 0x70, 0x03, 0x5b, 0x04, 0x49, 0x0f, 0x85,
0x2b, 0xff, 0xff, 0xff, 0xb8, 0x00, 0x00, 0x04, 0x00, 0xc7, 0x40, 0x10, 0xff, 0xff, 0x00, 0x00,
0xc7, 0x40, 0x14, 0x00, 0x9b, 0xcf, 0x00, 0xc7, 0x40, 0x18, 0xff, 0xff, 0x00, 0x00, 0xc7, 0x40,
0x1c, 0x00, 0x93, 0xcf, 0x00, 0xc6, 0x00, 0x2b, 0x89, 0x40, 0x02, 0x0f, 0x01, 0x10, 0xbe, 0x00,
0x00, 0x09, 0x00, 0xff, 0x25, 0x14, 0x02, 0x09, 0x00, 0xf4, 0xeb, 0xfd
};
unsigned int trampoline_len = 239;
unsigned int trampoline_len = 316;