Re: [PATCH 3/3] Update Linux loader to follow the kernel's preferences

[Keshav P R]

Fails to boot x86_64 Archlinux kernels 3.2.2 and 3.3-rc2 - premature
end of file error. The first 2 patches work fine (no noticable
difference). Only this patch leads to boot failure. Tested in
Tianocore UDK DuetPkg 64-bit firmware. Also a syntax error (missing
comma) in the very last change in this patch.

- Keshav

PS: Sent from my mobile. Pls ignore top posting.

On 04/02/2012, Matthew Garrett <address@hidden> wrote:
> We should attempt to load the kernel at its preferred address, and if
> we can't do that then we should at least align it correctly. When doing
> so we should also make sure to avoid putting the kernel on top of any
> regions being used by the firmware.
>
> ---
>  ChangeLog                     |    8 +++++
>  grub-core/loader/i386/linux.c |   67
> +++++++++++++++++++++++++++++++++++-----
>  2 files changed, 66 insertions(+), 9 deletions(-)
>
> diff --git a/ChangeLog b/ChangeLog
> index 0a94fc0..1e0270b 100644
> --- a/ChangeLog
> +++ b/ChangeLog
> @@ -1,5 +1,13 @@
>  2012-02-03  Matthew Garrett  <address@hidden>
>
> +     * grub-core/loader/i386/linux.c (allocate_pages): Attempt to obtain
> +     appropriately aligned memory if the desired target is unavailable
> +     (grub_cmd_linux): Update to match newer Linux boot protocols, and
> +     attempt to load the kernel at its preferred address rather than
> +     hardcoding.
> +
> +2012-02-03  Matthew Garrett  <address@hidden>
> +
>       * grub-core/lib/efi/relocator.c (grub_relocator_alloc_chunk_addr):
>       Add argument to fail allocation when target address overlaps
>       firmware regions. All users updated.
> diff --git a/grub-core/loader/i386/linux.c b/grub-core/loader/i386/linux.c
> index 67a4533..b61749d 100644
> --- a/grub-core/loader/i386/linux.c
> +++ b/grub-core/loader/i386/linux.c
> @@ -183,13 +183,14 @@ free_pages (void)
>    grub_relocator_unload (relocator);
>    relocator = NULL;
>    real_mode_mem = prot_mode_mem = initrd_mem = 0;
> -  real_mode_target = prot_mode_target = initrd_mem_target = 0;
> +  real_mode_target = initrd_mem_target = 0;
>  }
>
>  /* Allocate pages for the real mode code and the protected mode code
>     for linux as well as a memory map buffer.  */
>  static grub_err_t
> -allocate_pages (grub_size_t prot_size)
> +allocate_pages (grub_size_t prot_size, grub_size_t *align,
> +             grub_size_t min_align)
>  {
>    grub_size_t real_size, mmap_size;
>    grub_err_t err;
> @@ -269,18 +270,37 @@ allocate_pages (grub_size_t prot_size)
>                                           + efi_mmap_size), 0);
>      if (err)
>        goto fail;
> +
> +    grub_errno = GRUB_ERR_NONE;
>      real_mode_mem = get_virtual_current_address (ch);
>    }
>    efi_mmap_buf = (grub_uint8_t *) real_mode_mem + real_size + mmap_size;
>
> -  prot_mode_target = GRUB_LINUX_BZIMAGE_ADDR;
> -
>    {
>      grub_relocator_chunk_t ch;
>      err = grub_relocator_alloc_chunk_addr (relocator, &ch,
> -                                        prot_mode_target, prot_size, 0);
> +                                        prot_mode_target, prot_size, 1);
> +    if (err)
> +      {
> +     unsigned int i;
> +     for (i = *align; i >= min_align; i--)
> +       {
> +         err = grub_relocator_alloc_chunk_align (relocator, &ch,
> +                                                 0x1000000, 0xffffffff,
> +                                                 prot_size, 1 << i,
> +                                                 
> GRUB_RELOCATOR_PREFERENCE_LOW);
> +         if (!err)
> +           {
> +             *align = i;
> +             prot_mode_target = get_physical_target_address (ch);
> +             break;
> +           }
> +       }
> +      }
> +
>      if (err)
>        goto fail;
> +
>      prot_mode_mem = get_virtual_current_address (ch);
>    }
>
> @@ -631,7 +651,7 @@ grub_cmd_linux (grub_command_t cmd __attribute__
> ((unused)),
>    struct linux_kernel_header lh;
>    struct linux_kernel_params *params;
>    grub_uint8_t setup_sects;
> -  grub_size_t real_size, prot_size;
> +  grub_size_t real_size, prot_size, prot_file_size, align = 0, min_align =
> 0;
>    grub_ssize_t len;
>    int i;
>
> @@ -705,9 +725,31 @@ grub_cmd_linux (grub_command_t cmd __attribute__
> ((unused)),
>      setup_sects = GRUB_LINUX_DEFAULT_SETUP_SECTS;
>
>    real_size = setup_sects << GRUB_DISK_SECTOR_BITS;
> -  prot_size = grub_file_size (file) - real_size - GRUB_DISK_SECTOR_SIZE;
>
> -  if (allocate_pages (prot_size))
> +  if (grub_le_to_cpu16 (lh.version) >= 0x205)
> +    {
> +      for (align = 0; align < 32; align++)
> +     {
> +       if (grub_le_to_cpu32 (lh.kernel_alignment) & (1 << align))
> +         break;
> +     }
> +    }
> +
> +  if (grub_le_to_cpu16 (lh.version) >= 0x020a)
> +    {
> +      min_align = lh.min_alignment;
> +      prot_size = grub_le_to_cpu32 (lh.init_size);
> +      prot_mode_target = grub_le_to_cpu64 (lh.pref_address);
> +    }
> +  else
> +    {
> +      min_align = 0;
> +      prot_size = grub_file_size (file) - real_size -
> GRUB_DISK_SECTOR_SIZE;
> +      prot_mode_target = grub_le_to_cpu32 (lh.code32_start);
> +    }
> +
> +  prot_file_size = grub_file_size (file) - real_size -
> GRUB_DISK_SECTOR_SIZE;
> +  if (allocate_pages (prot_size, &align, min_align))
>      goto fail;
>
>    params = (struct linux_kernel_params *) real_mode_mem;
> @@ -715,6 +757,8 @@ grub_cmd_linux (grub_command_t cmd __attribute__
> ((unused)),
>    grub_memcpy (&params->setup_sects, &lh.setup_sects, sizeof (lh) - 0x1F1);
>
>    params->ps_mouse = params->padding10 =  0;
> +  params->code32_start = prot_mode_target;
> +  params->kernel_alignment = (1 << align);
>
>    len = 0x400 - sizeof (lh);
>    if (grub_file_read (file, (char *) real_mode_mem + sizeof (lh), len) !=
> len)
> @@ -774,7 +818,7 @@ grub_cmd_linux (grub_command_t cmd __attribute__
> ((unused)),
>    grub_file_seek (file, real_size + GRUB_DISK_SECTOR_SIZE);
>
>    grub_dprintf ("linux", "bzImage, setup=0x%x, size=0x%x\n",
> -             (unsigned) real_size, (unsigned) prot_size);
> +             (unsigned) real_size, (unsigned) prot_file_size);
>
>    /* Look for memory size and video mode specified on the command line.  */
>    linux_mem_size = 0;
> @@ -916,6 +960,11 @@ grub_cmd_linux (grub_command_t cmd __attribute__
> ((unused)),
>      grub_error (GRUB_ERR_FILE_READ_ERROR, N_("premature end of file %s"),
>               argv[0]);
>
> +  len = prot_file_size;
> +  if (grub_file_read (file, prot_mode_mem, len) != len && !grub_errno)
> +    grub_error (GRUB_ERR_FILE_READ_ERROR, N_("premature end of file %s")
> +             argv[0]);
> +
>    if (grub_errno == GRUB_ERR_NONE)
>      {
>        grub_loader_set (grub_linux_boot, grub_linux_unload,
> --
> 1.7.7.6
>
>
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