[RFT PATCH] efi: map memreserve table before first use

[Jan.Glauber@cavium.com (Jan Glauber)]

On Tue, Nov 20, 2018 at 06:35:42PM +0100, Ard Biesheuvel wrote:
> Mapping the MEMRESERVE EFI configuration table from an early initcall
> is too late: the GICv3 ITS code that creates persistent reservations
> for the boot CPU's LPI tables is invoked from init_IRQ(), which runs
> much earlier than the handling of the initcalls.
> 
> So instead, move the initialization performed by the initcall into
> efi_mem_reserve_persistent() itself.
> 
> Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
> ---
>  drivers/firmware/efi/efi.c | 26 ++++++++++----------------
>  1 file changed, 10 insertions(+), 16 deletions(-)
> 
> diff --git a/drivers/firmware/efi/efi.c b/drivers/firmware/efi/efi.c
> index fad7c62cfc0e..40de2f6734cc 100644
> --- a/drivers/firmware/efi/efi.c
> +++ b/drivers/firmware/efi/efi.c
> @@ -967,15 +967,23 @@ bool efi_is_table_address(unsigned long phys_addr)
>  }
> 
>  static DEFINE_SPINLOCK(efi_mem_reserve_persistent_lock);
> -static struct linux_efi_memreserve *efi_memreserve_root __ro_after_init;
> +static struct linux_efi_memreserve *efi_memreserve_root;
> 
>  int efi_mem_reserve_persistent(phys_addr_t addr, u64 size)
>  {
>         struct linux_efi_memreserve *rsv;
> 
> -       if (!efi_memreserve_root)
> +       if (efi.mem_reserve == EFI_INVALID_TABLE_ADDR)
>                 return -ENODEV;
> 
> +       if (!efi_memreserve_root) {
> +               efi_memreserve_root = memremap(efi.mem_reserve,
> +                                              sizeof(*efi_memreserve_root),
> +                                              MEMREMAP_WB);
> +               if (WARN_ON_ONCE(!efi_memreserve_root))
> +                       return -ENOMEM;
> +       }
> +
>         rsv = kmalloc(sizeof(*rsv), GFP_ATOMIC);
>         if (!rsv)
>                 return -ENOMEM;
> @@ -991,20 +999,6 @@ int efi_mem_reserve_persistent(phys_addr_t addr, u64 size)
>         return 0;
>  }
> 
> -static int __init efi_memreserve_root_init(void)
> -{
> -       if (efi.mem_reserve == EFI_INVALID_TABLE_ADDR)
> -               return -ENODEV;
> -
> -       efi_memreserve_root = memremap(efi.mem_reserve,
> -                                      sizeof(*efi_memreserve_root),
> -                                      MEMREMAP_WB);
> -       if (!efi_memreserve_root)
> -               return -ENOMEM;
> -       return 0;
> -}
> -early_initcall(efi_memreserve_root_init);
> -
>  #ifdef CONFIG_KEXEC
>  static int update_efi_random_seed(struct notifier_block *nb,
>                                   unsigned long code, void *unused)
> --
> 2.17.1

Hi Ard,

thanks for the patch, it works fine for me.

If you want:
Tested-by: Jan Glauber <jglauber@cavium.com>

--Jan