Subject: [PATCH] arm64: ignore DT memreserve entries when booting in UEFI mode

From: [email-masked] (Catalin Marinas)
Date: Mon, 18 Aug 2014 15:24:49 +0100

On Wed, Aug 13, 2014 at 01:22:39PM +0100, Leif Lindholm wrote:
> On Mon, Jul 28, 2014 at 07:14:49PM +0100, Mark Rutland wrote:
> > On Mon, Jul 28, 2014 at 07:03:03PM +0100, Leif Lindholm wrote:
> > > UEFI provides its own method for marking regions to reserve, via the
> > > memory map which is also used to initialise memblock. So when using the
> > > UEFI memory map, ignore any memreserve entries present in the DT.
> > 
> > It's worth noting that no-one is relying on this at present, and were
> > they it would imply that their UEFI implementation is broken (providing
> > a dodgy memory map).
> > 
> > So before people start doing dodgy things, let's, close that hole. If we
> > need a way of modifying the memory map we should come up with a more
> > general plan.
> 
> Catalin - any comments?
> As it is a bugfix, can it go into 3.17?

It looks fine to me:

Acked-by: Catalin Marinas <[email-masked]>

(cc'ing Will who handles the 3.17 merging)

> > > Reported-by: Mark Rutland <[email-masked]>
> > > Signed-off-by: Leif Lindholm <[email-masked]>
> > > ---
> > >  arch/arm64/kernel/efi.c |    2 ++
> > >  arch/arm64/mm/init.c    |    4 +++-
> > >  2 files changed, 5 insertions(+), 1 deletion(-)
> > > 
> > > diff --git a/arch/arm64/kernel/efi.c b/arch/arm64/kernel/efi.c
> > > index 14db1f6..7ad17b2 100644
> > > --- a/arch/arm64/kernel/efi.c
> > > +++ b/arch/arm64/kernel/efi.c
> > > @@ -188,6 +188,8 @@ static __init void reserve_regions(void)
> > >  		if (uefi_debug)
> > >  			pr_cont("\n");
> > >  	}
> > > +
> > > +	set_bit(EFI_MEMMAP, &efi.flags);
> > >  }
> > >  
> > >  
> > > diff --git a/arch/arm64/mm/init.c b/arch/arm64/mm/init.c
> > > index e90c542..58dbf2e 100644
> > > --- a/arch/arm64/mm/init.c
> > > +++ b/arch/arm64/mm/init.c
> > > @@ -32,6 +32,7 @@
> > >  #include <linux/of_fdt.h>
> > >  #include <linux/dma-mapping.h>
> > >  #include <linux/dma-contiguous.h>
> > > +#include <linux/efi.h>
> > >  
> > >  #include <asm/sections.h>
> > >  #include <asm/setup.h>
> > > @@ -151,7 +152,8 @@ void __init arm64_memblock_init(void)
> > >  	memblock_reserve(__pa(swapper_pg_dir), SWAPPER_DIR_SIZE);
> > >  	memblock_reserve(__pa(idmap_pg_dir), IDMAP_DIR_SIZE);
> > >  
> > > -	early_init_fdt_scan_reserved_mem();
> > > +	if (!efi_enabled(EFI_MEMMAP))
> > > +		early_init_fdt_scan_reserved_mem();