Re: [PATCH 2/2] Ensure nvram is available and functional on IEEE1275

[Michael Chang]

On Wed, Aug 24, 2022 at 06:03:11PM +0200, Ismael Luceno wrote:
> Otherwise the installation will fail, and the system will be left in an
> unbootable state.
> 
> On ppc64le, the boot process shows:
> 
>       Welcome to GRUB!
> 
>       error: ../../grub-core/kern/dl.c:380:symbol `grub_disk_get_size' not 
> found.
>       Entering rescue mode...
>       grub rescue>

The symbol looking up failure due to failed grub-install attempt should
not happen in the first place given this commit should bail it out.

  8ddbdc3bc2 grub-install: Add backup and restore

Apparently there's missing grub_set_install_backup_ponr between
successful image embedding and grub_install_register_ieee1275 and we
should fix that as well.

> 
> Signed-off-by: Ismael Luceno <iluceno@suse.de>
> ---
>  grub-core/osdep/unix/platform.c | 18 ++++++++++++++++++
>  1 file changed, 18 insertions(+)
> 
> diff --git a/grub-core/osdep/unix/platform.c b/grub-core/osdep/unix/platform.c
> index a5bf064b7cf5..fd23176e58a0 100644
> --- a/grub-core/osdep/unix/platform.c
> +++ b/grub-core/osdep/unix/platform.c
> @@ -192,12 +192,30 @@ grub_install_register_efi (grub_device_t 
> efidir_grub_dev,
>    return ret;
>  }
>  
> +static void
> +linux_ensure_nvram (void)
> +{
> +  int fd;
> +#ifndef __linux__
> +  return 0;
> +#endif
> +  if (linux_kmod_load("nvram"))
> +    grub_util_error (_("%s: kernel module not found"), "nvram");
> +  fd = open ("/dev/nvram", O_RDWR);
> +  if (fd == -1)
> +    grub_util_error ("/dev/nvram: %s", strerror(errno));
> +  close (fd);
> +}
> +

I'm wondering why it is needed. The nvram module should be loaded
on-demand via linux kernel's request_module() and modalias trick whever
/dev/nvram is accessed.

Thanks,
Michael

>  void
>  grub_install_register_ieee1275 (int is_prep, const char *install_device,
>                               int partno, const char *relpath)
>  {
>    char *boot_device;
>  
> +  /* On Linux, ensure nvram is available and functional.  */
> +  linux_ensure_nvram ();
> +
>    if (grub_util_exec_redirect_null ((const char * []){ "ofpathname", 
> "--version", NULL }))
>      {
>        /* TRANSLATORS: This message is shown when required executable `%s'
> -- 
> 2.37.1
> 
> 
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