Re: [PATCH 3/7] ppc/pnv: Use skiboot addresses to load kernel and ramfs

[Murilo Opsfelder Araújo]

Bonjour, Cédric.

On Tuesday, January 26, 2021 2:10:55 PM -03 Cédric Le Goater wrote:
> The current settings are useful to load large kernels (with debug) but
> it moves the initrd image in a memory region not protected by
> skiboot. If skiboot is compiled with DEBUG=1, memory poisoning will
> corrupt the initrd.
> 
> Cc: Murilo Opsfelder Araujo <muriloo@linux.ibm.com>
> Signed-off-by: Cédric Le Goater <clg@kaod.org>
> ---
> 
>  If we want to increase the kernel size limit as commit b45b56baeecd
>  ("ppc/pnv: increase kernel size limit to 256MiB") intented to do, I
>  think we should add a machine option.

Is this a problem on bare-metal as well?

I'm wondering if we should address this the other way around by increasing
KERNEL_LOAD_SIZE and INITRAMFS_LOAD_SIZE in skiboot to accomodate large kernel
and initramfs images.

I think Linux debuginfo images won't get smaller with time and, assuming this
also happens on bare-metal (I haven't verified), updating skiboot looks more
appropriate.

Bear in mind that I'm not an skiboot expert, I'm just considering the
possibilities.

> 
>  hw/ppc/pnv.c | 6 +++---
>  1 file changed, 3 insertions(+), 3 deletions(-)
> 
> diff --git a/hw/ppc/pnv.c b/hw/ppc/pnv.c
> index 14fc9758a973..e500c2e2437e 100644
> --- a/hw/ppc/pnv.c
> +++ b/hw/ppc/pnv.c
> @@ -65,9 +65,9 @@
>  #define FW_MAX_SIZE             (16 * MiB)
> 
>  #define KERNEL_LOAD_ADDR        0x20000000
> -#define KERNEL_MAX_SIZE         (256 * MiB)
> -#define INITRD_LOAD_ADDR        0x60000000
> -#define INITRD_MAX_SIZE         (256 * MiB)
> +#define KERNEL_MAX_SIZE         (128 * MiB)
> +#define INITRD_LOAD_ADDR        0x28000000
> +#define INITRD_MAX_SIZE         (128 * MiB)
> 
>  static const char *pnv_chip_core_typename(const PnvChip *o)
>  {

Cheers!

-- 
Murilo