linux-kernel.vger.kernel.org archive mirror
 help / color / mirror / Atom feed
From: Andre Przywara <andre.przywara@arm.com>
To: Will Deacon <will@kernel.org>, Catalin Marinas <catalin.marinas@arm.com>
Cc: Marc Zyngier <maz@kernel.org>,
	Mark Rutland <mark.rutland@arm.com>,
	Jonathan Corbet <corbet@lwn.net>,
	linux-arm-kernel@lists.infradead.org, linux-doc@vger.kernel.org,
	linux-kernel@vger.kernel.org
Subject: [PATCH 1/2] arm64: booting.rst: Clarify on requiring non-secure EL2
Date: Fri,  7 Jan 2022 16:00:55 +0000	[thread overview]
Message-ID: <20220107160056.322141-2-andre.przywara@arm.com> (raw)
In-Reply-To: <20220107160056.322141-1-andre.przywara@arm.com>

The ARMv8.4 architecture revision introduced the EL2 exception level
to the secure world. Clarify the existing wording to make sure that
Linux relies on being executed in the non-secure state.

Signed-off-by: Andre Przywara <andre.przywara@arm.com>
---
 Documentation/arm64/booting.rst | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/Documentation/arm64/booting.rst b/Documentation/arm64/booting.rst
index 52d060caf8bb..07cb34ed4200 100644
--- a/Documentation/arm64/booting.rst
+++ b/Documentation/arm64/booting.rst
@@ -10,9 +10,9 @@ This document is based on the ARM booting document by Russell King and
 is relevant to all public releases of the AArch64 Linux kernel.
 
 The AArch64 exception model is made up of a number of exception levels
-(EL0 - EL3), with EL0 and EL1 having a secure and a non-secure
-counterpart.  EL2 is the hypervisor level and exists only in non-secure
-mode. EL3 is the highest priority level and exists only in secure mode.
+(EL0 - EL3), with EL0, EL1 and EL2 having a secure and a non-secure
+counterpart.  EL2 is the hypervisor level, EL3 is the highest priority
+level and exists only in secure mode. Both are architecturally optional.
 
 For the purposes of this document, we will use the term `boot loader`
 simply to define all software that executes on the CPU(s) before control
@@ -167,8 +167,8 @@ Before jumping into the kernel, the following conditions must be met:
 
   All forms of interrupts must be masked in PSTATE.DAIF (Debug, SError,
   IRQ and FIQ).
-  The CPU must be in either EL2 (RECOMMENDED in order to have access to
-  the virtualisation extensions) or non-secure EL1.
+  The CPU must be in non-secure state, either in EL2 (RECOMMENDED in order
+  to have access  to the virtualisation extensions), or in EL1.
 
 - Caches, MMUs
 
-- 
2.25.1


  reply	other threads:[~2022-01-07 16:01 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-01-07 16:00 [PATCH 0/2] arm64: booting.rst: Clarify EL2 and cover v8-R64 Andre Przywara
2022-01-07 16:00 ` Andre Przywara [this message]
2022-01-07 16:20   ` [PATCH 1/2] arm64: booting.rst: Clarify on requiring non-secure EL2 Mark Rutland
2022-01-07 16:00 ` [PATCH 2/2] arm64: booting.rst: Cover Armv8-R64 Andre Przywara
2022-01-07 16:27   ` Mark Rutland
2022-02-15 23:18 ` [PATCH 0/2] arm64: booting.rst: Clarify EL2 and cover v8-R64 Will Deacon

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20220107160056.322141-2-andre.przywara@arm.com \
    --to=andre.przywara@arm.com \
    --cc=catalin.marinas@arm.com \
    --cc=corbet@lwn.net \
    --cc=linux-arm-kernel@lists.infradead.org \
    --cc=linux-doc@vger.kernel.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=mark.rutland@arm.com \
    --cc=maz@kernel.org \
    --cc=will@kernel.org \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body. 
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).