From mboxrd@z Thu Jan 1 00:00:00 1970 From: marc.zyngier@arm.com (Marc Zyngier) Date: Wed, 5 Feb 2014 13:30:35 +0000 Subject: [PATCH 03/18] arm64: boot protocol documentation update for GICv3 In-Reply-To: <1391607050-540-1-git-send-email-marc.zyngier@arm.com> References: <1391607050-540-1-git-send-email-marc.zyngier@arm.com> Message-ID: <1391607050-540-4-git-send-email-marc.zyngier@arm.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org Linux has some requirements that must be satisfied in order to boot on a system built with a GICv3. Signed-off-by: Marc Zyngier --- Documentation/arm64/booting.txt | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/Documentation/arm64/booting.txt b/Documentation/arm64/booting.txt index a9691cc..4a02ebd 100644 --- a/Documentation/arm64/booting.txt +++ b/Documentation/arm64/booting.txt @@ -131,6 +131,13 @@ Before jumping into the kernel, the following conditions must be met: the kernel image will be entered must be initialised by software at a higher exception level to prevent execution in an UNKNOWN state. + For systems with a GICv3 interrupt controller, it is expected that: + - ID_AA64PFR0_EL1.GIC (bits [27:24]) must have the value 0b0001 + - If EL3 is present, it must program ICC_SRE_EL3.Enable (bit 3) to + 0b1 and ICC_SRE_EL3.SRE (bit 0) to 0b1. + - If the kernel is entered at EL1, EL2 must set ICC_SRE_EL2.Enable + (bit 3) to 0b1 and ICC_SRE_EL2.SRE (bit 0) to 0b1. + The requirements described above for CPU mode, caches, MMUs, architected timers, coherency and system registers apply to all CPUs. All CPUs must enter the kernel in the same exception level. -- 1.8.3.4