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ieee1275: Include a.out header in assembly of sparc64 boot loader

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Recent versions of binutils dropped support for the a.out and COFF
formats on sparc64 targets. Since the boot loader on sparc64 is
supposed to be an a.out binary and the a.out header entries are
rather simple to calculate in our case, we just write the header
ourselves instead of relying on external tools to do that.

Signed-off-by: John Paul Adrian Glaubitz <glaubitz@physik.fu-berlin.de>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
This commit is contained in:
John Paul Adrian Glaubitz 2019-03-26 10:47:16 +01:00 committed by Daniel Kiper
parent f91e4d1633
commit 5635e799fd
3 changed files with 38 additions and 9 deletions
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16
grub-core/Makefile.core.def
View file

@ -425,8 +425,14 @@ image = {
i386_qemu_ldflags = '$(TARGET_IMG_BASE_LDOPT),$(GRUB_BOOT_MACHINE_LINK_ADDR)';
i386_qemu_ccasflags = '-DGRUB_BOOT_MACHINE_LINK_ADDR=$(GRUB_BOOT_MACHINE_LINK_ADDR)';
sparc64_ieee1275_objcopyflags = '-O a.out-sunos-big';
sparc64_ieee1275_ldflags = ' -Wl,-Ttext=0x4000';
/* The entry point for a.out binaries on sparc64 starts
at 0x4000. Since we are writing the 32 bytes long a.out
header in the assembly code ourselves, we need to tell
the linker to adjust the start of the text segment to
0x4000 - 0x20 = 0x3fe0.
*/
sparc64_ieee1275_ldflags = ' -Wl,-Ttext=0x3fe0';
sparc64_ieee1275_objcopyflags = '-O binary';
objcopyflags = '-O binary';
enable = i386_pc;
@ -455,8 +461,10 @@ image = {
i386_pc_ldflags = '$(TARGET_IMG_BASE_LDOPT),0x7C00';
sparc64_ieee1275 = boot/sparc64/ieee1275/boot.S;
sparc64_ieee1275_objcopyflags = '-O a.out-sunos-big';
sparc64_ieee1275_ldflags = ' -Wl,-Ttext=0x4000';
/* See comment for sparc64_ieee1275_ldflags above. */
sparc64_ieee1275_ldflags = ' -Wl,-Ttext=0x3fe0';
sparc64_ieee1275_objcopyflags = '-O binary';
sparc64_ieee1275_cppflags = '-DCDBOOT=1';
objcopyflags = '-O binary';

28
grub-core/boot/sparc64/ieee1275/boot.S
View file

@ -21,6 +21,24 @@
.text
.align 4
/*
* We're writing the a.out header ourselves as newer
* upstream versions of binutils no longer support
* the a.out format on sparc64.
*
* The boot loader fits into 512 bytes with 32 bytes
* used for the a.out header, hence the text segment
* size is 512 - 32. There is no data segment and no
* code relocation, thus those fields remain zero.
*/
.word 0x1030107 /* Magic number. */
.word 512 - GRUB_BOOT_AOUT_HEADER_SIZE /* Size of text segment. */
.word 0 /* Size of initialized data. */
.word 0 /* Size of uninitialized data. */
.word 0 /* Size of symbol table || checksum. */
.word _start /* Entry point. */
.word 0 /* Size of text relocation. */
.word 0 /* Size of data relocation. */
.globl _start
_start:
/* OF CIF entry point arrives in %o4 */
@ -40,10 +58,14 @@ pic_base:
*
* After loading in that block we will execute it by jumping to the
* load address plus the size of the prepended A.OUT header (32 bytes).
*
* Since this assembly code includes the 32 bytes long a.out header,
* we need to move the actual code entry point forward by the size
* of the a.out header, i.e. += GRUB_BOOT_AOUT_HEADER_SIZE.
*/
.org GRUB_BOOT_MACHINE_BOOT_DEVPATH
.org GRUB_BOOT_MACHINE_BOOT_DEVPATH + GRUB_BOOT_AOUT_HEADER_SIZE
boot_path:
.org GRUB_BOOT_MACHINE_KERNEL_BYTE
.org GRUB_BOOT_MACHINE_KERNEL_BYTE + GRUB_BOOT_AOUT_HEADER_SIZE
boot_path_end:
kernel_byte: .xword (2 << 9)
kernel_address: .word GRUB_BOOT_MACHINE_KERNEL_ADDR
@ -52,7 +74,7 @@ kernel_address: .word GRUB_BOOT_MACHINE_KERNEL_ADDR
#define boot_path_end (_start + 1024)
#include <grub/offsets.h>
.org 8
.org 8 + GRUB_BOOT_AOUT_HEADER_SIZE
kernel_byte: .xword (2 << 9)
kernel_size: .word 512
kernel_address: .word GRUB_BOOT_SPARC64_IEEE1275_IMAGE_ADDRESS

3
include/grub/sparc64/ieee1275/boot.h
View file

@ -46,8 +46,7 @@
#define GRUB_BOOT_MACHINE_KERNEL_BYTE 0x80
#define GRUB_BOOT_MACHINE_CODE_END \
(0x1fc - GRUB_BOOT_AOUT_HEADER_SIZE)
#define GRUB_BOOT_MACHINE_CODE_END 0x1fc
#define GRUB_BOOT_MACHINE_KERNEL_ADDR 0x4200