From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752603AbbJOJsS (ORCPT ); Thu, 15 Oct 2015 05:48:18 -0400 Received: from eu-smtp-delivery-143.mimecast.com ([146.101.78.143]:24621 "EHLO eu-smtp-delivery-143.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751322AbbJOJsR convert rfc822-to-8bit (ORCPT ); Thu, 15 Oct 2015 05:48:17 -0400 Subject: Re: [PATCHv3 08/11] arm64: Check for selected granule support To: Jeremy Linton , linux-arm-kernel@lists.infradead.org References: <1444821634-1689-1-git-send-email-suzuki.poulose@arm.com> <1444821634-1689-9-git-send-email-suzuki.poulose@arm.com> <561EC58B.9080408@arm.com> Cc: mark.rutland@arm.com, steve.capper@linaro.org, ard.biesheuvel@linaro.org, marc.zyngier@arm.com, catalin.marinas@arm.com, will.deacon@arm.com, linux-kernel@vger.kernel.org, christoffer.dall@linaro.org From: "Suzuki K. Poulose" Message-ID: <561F765D.8090400@arm.com> Date: Thu, 15 Oct 2015 10:48:13 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:38.0) Gecko/20100101 Thunderbird/38.2.0 MIME-Version: 1.0 In-Reply-To: <561EC58B.9080408@arm.com> X-OriginalArrivalTime: 15 Oct 2015 09:48:13.0614 (UTC) FILETIME=[9BE9DCE0:01D1072E] X-MC-Unique: Cg-LV9l7SdClxQiDBovBkg-1 Content-Type: text/plain; charset=WINDOWS-1252; format=flowed Content-Transfer-Encoding: 8BIT Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 14/10/15 22:13, Jeremy Linton wrote: > On 10/14/2015 06:20 AM, Suzuki K. Poulose wrote: > >> + * Checks if the selected granule size is supported by the CPU. >> + * If it doesn't park the CPU > > The problem is when you park the boot CPU. > > I think for EFI there is a slightly better error mechanism. This tweak will print an > error and return to the EFI boot manager rather than hanging the machine without any > notification. Now it prints: > > EFI stub: Booting Linux Kernel... > EFI stub: ERROR: 16K granule not supported by this machine > EFI stub: ERROR: Failed to relocate kernel > FS4:\> Nice ! I will pick this up. > > > Signed-off-by: Jeremy Linton > --- > arch/arm64/kernel/efi-stub.c | 14 ++++++++++++++ > 1 file changed, 14 insertions(+) > > diff --git a/arch/arm64/kernel/efi-stub.c b/arch/arm64/kernel/efi-stub.c > index 816120e..90fb868 100644 > --- a/arch/arm64/kernel/efi-stub.c > +++ b/arch/arm64/kernel/efi-stub.c > @@ -25,6 +25,20 @@ efi_status_t __init handle_kernel_image(efi_system_table_t *sys_table_arg, > unsigned long kernel_size, kernel_memsize = 0; > unsigned long nr_pages; > void *old_image_addr = (void *)*image_addr; > + u32 aa64mmfr0_el1; > + > +#ifdef CONFIG_ARM64_16K_PAGES I would prefer to have it on for all page sizes and not just 16K, to be on a safer side > + /* > + * check to see if this kernel image is > + * compatible with the current system > + */ > + asm volatile("mrs %0, ID_AA64MMFR0_EL1" : "=r" (aa64mmfr0_el1)); > + aa64mmfr0_el1 >>= ID_AA64MMFR0_TGRAN16_SHIFT; > + if ((aa64mmfr0_el1 & ID_AA64MMFR0_TGRAN4_ON) == 0) { > + pr_efi_err(sys_table_arg, "16K granule not supported by this machine\n"); > + return EFI_UNSUPPORTED; > + } > +#endif Thanks Suzuki