From mboxrd@z Thu Jan 1 00:00:00 1970 From: Mark Rutland Subject: Re: [PATCH] arm64: ignore DT memreserve entries when booting in UEFI mode Date: Mon, 28 Jul 2014 19:14:49 +0100 Message-ID: <20140728181449.GF2576@leverpostej> References: <1406570583-22848-1-git-send-email-leif.lindholm@linaro.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: <1406570583-22848-1-git-send-email-leif.lindholm-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org> Sender: linux-efi-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Leif Lindholm Cc: "linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org" , "msalter-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org" , Catalin Marinas , "linux-efi-u79uwXL29TY76Z2rM5mHXA@public.gmane.org" , rob.herring-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org List-Id: linux-efi@vger.kernel.org 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. > Reported-by: Mark Rutland > Signed-off-by: Leif Lindholm > --- > 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); Nothing outside of arch/x86 seems to hang off this, so using it here looks fine. > } > > > 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 > #include > #include > +#include > > #include > #include > @@ -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(); And this is a false stub for !EFI, so that looks fine. FWIW: Reviewed-by: Mark Rutland I wonder if we have any other flat tree uses we need to be careful of when booting via EFI. Thanks Mark. > > /* 4GB maximum for 32-bit only capable devices */ > if (IS_ENABLED(CONFIG_ZONE_DMA)) > -- > 1.7.10.4 > >