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

[John Garry <john.garry@xxxxxxxxxx>]

On 21/11/2018 09:56, Jan Glauber wrote:
> 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@xxxxxxxxxx>
> > ---
> >  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@xxxxxxxxxx>

FWIW, the splat is gone:

Tested-by: John Garry <john.garry@xxxxxxxxxx>

> --Jan