Re: [PATCH] ieee1275: Include a.out header in assembly of sparc64 boot loader

[John Paul Adrian Glaubitz]

This is supposed to be version 3. Forgot to edit the subject.

Adrian

On 2/9/19 2:39 PM, John Paul Adrian Glaubitz wrote:
> 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 <address@hidden>
> ---
> v2:
> - fix grammar in long description
> v3:
> - fix formatting in assembly code
> - update comment in boot loader for consistency
> 
>  grub-core/Makefile.core.def            |  6 ++----
>  grub-core/boot/sparc64/ieee1275/boot.S | 18 +++++++++++++++---
>  include/grub/sparc64/ieee1275/boot.h   |  3 +--
>  3 files changed, 18 insertions(+), 9 deletions(-)
> 
> diff --git a/grub-core/Makefile.core.def b/grub-core/Makefile.core.def
> index e16fb06ba..f9f845828 100644
> --- a/grub-core/Makefile.core.def
> +++ b/grub-core/Makefile.core.def
> @@ -402,8 +402,7 @@ image = {
>    i386_qemu_ldflags = 
> '$(TARGET_IMG_BASE_LDOPT),$(GRUB_BOOT_MACHINE_LINK_ADDR)';
>    i386_qemu_ccasflags = 
> '-DGRUB_BOOT_MACHINE_LINK_ADDR=$(GRUB_BOOT_MACHINE_LINK_ADDR)';
>  
> -  sparc64_ieee1275_objcopyflags = '-O a.out-sunos-big';
> -  sparc64_ieee1275_ldflags = ' -Wl,-Ttext=0x4000';
> +  sparc64_ieee1275_ldflags = ' -Wl,-Ttext=0x3fe0';
>  
>    objcopyflags = '-O binary';
>    enable = i386_pc;
> @@ -432,8 +431,7 @@ image = {
>    i386_pc_ldflags = '$(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';
> +  sparc64_ieee1275_ldflags = ' -Wl,-Ttext=0x3fe0';
>    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..a534e1853 100644
> --- a/grub-core/boot/sparc64/ieee1275/boot.S
> +++ b/grub-core/boot/sparc64/ieee1275/boot.S
> @@ -21,6 +21,18 @@
>  
>       .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.
> +      */
> +     .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 */
> @@ -41,9 +53,9 @@ 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).
>        */
> -     .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 +64,7 @@ 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
> 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
>  
> 

-- 
 .''`.  John Paul Adrian Glaubitz
: :' :  Debian Developer - address@hidden
`. `'   Freie Universitaet Berlin - address@hidden
  `-    GPG: 62FF 8A75 84E0 2956 9546  0006 7426 3B37 F5B5 F913