From 5635e799fd7e14a8435f60f163706270c2109041 Mon Sep 17 00:00:00 2001 From: John Paul Adrian Glaubitz Date: Tue, 26 Mar 2019 10:47:16 +0100 Subject: [PATCH] ieee1275: Include a.out header in assembly of sparc64 boot loader 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 Reviewed-by: Daniel Kiper --- grub-core/Makefile.core.def | 16 +++++++++++---- grub-core/boot/sparc64/ieee1275/boot.S | 28 +++++++++++++++++++++++--- include/grub/sparc64/ieee1275/boot.h | 3 +-- 3 files changed, 38 insertions(+), 9 deletions(-) diff --git a/grub-core/Makefile.core.def b/grub-core/Makefile.core.def index 43ed42191..474a63e68 100644 --- a/grub-core/Makefile.core.def +++ b/grub-core/Makefile.core.def @@ -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'; diff --git a/grub-core/boot/sparc64/ieee1275/boot.S b/grub-core/boot/sparc64/ieee1275/boot.S index 9ea9b4e06..374928ed2 100644 --- a/grub-core/boot/sparc64/ieee1275/boot.S +++ b/grub-core/boot/sparc64/ieee1275/boot.S @@ -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 - .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 diff --git a/include/grub/sparc64/ieee1275/boot.h b/include/grub/sparc64/ieee1275/boot.h index 02d53f28e..cc5a941e3 100644 --- a/include/grub/sparc64/ieee1275/boot.h +++ b/include/grub/sparc64/ieee1275/boot.h @@ -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