[Skiboot] [PATCH 2/4] Start preload of kernel and initramfs early in boot

[Joel Stanley]

On Fri, May 1, 2015 at 5:26 PM, Stewart Smith
<stewart at linux.vnet.ibm.com> wrote:
> This means we will load kernel and initramfs LIDs from FSP/flash
> as we init PCI, hopefully reducing boot time.

In the case of no initramfs (all current BMC machines) it looks like
we'll print an error. Aside from that it looks good.

>
> Signed-off-by: Stewart Smith <stewart at linux.vnet.ibm.com>

Reviewed-by: Joel Stanley <joel at jms.id.au>

> ---
>  core/init.c |   80 +++++++++++++++++++++++++++++++++++++----------------------
>  1 file changed, 50 insertions(+), 30 deletions(-)
>
> diff --git a/core/init.c b/core/init.c

>         /* Try to load an external kernel payload through the platform hooks */
> -       ksize = KERNEL_LOAD_SIZE;
> +       kernel_size = KERNEL_LOAD_SIZE;
>         loaded = start_preload_resource(RESOURCE_ID_KERNEL,
>                                         RESOURCE_SUBID_NONE,
>                                         KERNEL_LOAD_BASE,
> -                                       &ksize);
> -       if (loaded == OPAL_SUCCESS)
> -               loaded = wait_for_resource_loaded(RESOURCE_ID_KERNEL,
> -                                                 RESOURCE_SUBID_NONE);
> +                                       &kernel_size);
> +       if (loaded != OPAL_SUCCESS) {
> +               printf("INIT: platform start load kernel failed\n");
> +               kernel_size = 0;
> +               return false;
> +       }
>
> +       initramfs_size = INITRAMFS_LOAD_SIZE;
> +       loaded = start_preload_resource(RESOURCE_ID_INITRAMFS,
> +                                       RESOURCE_SUBID_NONE,
> +                                       INITRAMFS_LOAD_BASE, &initramfs_size);
>         if (loaded != OPAL_SUCCESS) {
> -               printf("INIT: platform kernel load failed\n");
> -               ksize = 0;
> +               printf("INIT: platform start load initramfs failed\n");

We will get that message on BMC machines when nothing has gone wrong.

> +               initramfs_size = 0;
> +               return false;

And we will return false from here. How does this work on a BMC machine?

>  void __noreturn load_and_boot_kernel(bool is_reboot)
> @@ -696,6 +714,8 @@ void __noreturn main_cpu_entry(const void *fdt, u32 master_cpu)
>         /* Probe PHB3 on P8 */
>         probe_phb3();
>
> +       start_preload_kernel();
> +
>         /* Initialize PCI */
>         pci_init_slots();

Ah, this works on a BMC machine as we don't check to see if
start_preload_kernel succeeded or not.