linux-arm-kernel.lists.infradead.org archive mirror
 help / color / mirror / Atom feed
From: Mark Rutland <mark.rutland@arm.com>
To: linux-arm-kernel@lists.infradead.org
Cc: Andre.Przywara@arm.com, Jaxson.Han@arm.com, mark.rutland@arm.com,
	Wei.Chen@arm.com
Subject: [boot-wrapper PATCH 04/12] Remove `flag_no_el3`
Date: Thu, 29 Jul 2021 16:20:42 +0100	[thread overview]
Message-ID: <20210729152050.23635-5-mark.rutland@arm.com> (raw)
In-Reply-To: <20210729152050.23635-1-mark.rutland@arm.com>

We set `flag_no_el3` when not booted at EL3 / monitor mode, and
subsequently we use this to determine whether we need to drop exception
level before entering Linux. As this can be derived from CurrentEL or
CPSR, the flag itself is redundant, and we can defer the check until
we're about to enter Linux.

In future this will allow more logic to be converted into C, where it
will be easier to handle architectural variants.

Signed-off-by: Mark Rutland <mark.rutland@arm.com>
---
 arch/aarch32/boot.S | 14 +++-----------
 arch/aarch64/boot.S | 13 ++-----------
 2 files changed, 5 insertions(+), 22 deletions(-)

diff --git a/arch/aarch32/boot.S b/arch/aarch32/boot.S
index 2a85ad5..0bd1ca2 100644
--- a/arch/aarch32/boot.S
+++ b/arch/aarch32/boot.S
@@ -31,9 +31,6 @@ ENTRY(_start)
 	cmp	r0, #PSR_HYP
 	bne	_switch_monitor
 
-	mov	r0, #1
-	ldr	r1, =flag_no_el3
-	str	r0, [r1]
 	b	start_no_el3
 
 _switch_monitor:
@@ -89,9 +86,9 @@ ENTRY(jump_kernel)
 	ldr	lr, [r5], #4
 	ldm	r5, {r0 - r2}
 
-	ldr	r4, =flag_no_el3
-	ldr	r4, [r4]
-	cmp	r4, #1
+	mrs	r4, cpsr
+	and	r4, #PSR_MODE_MASK
+	cmp	r4, #PSR_MON
 	bxeq	lr				@ no EL3
 
 	ldr	r4, =SPSR_KERNEL
@@ -113,8 +110,3 @@ boot_vectors:
 	b	.
 	b	.
 	b	.
-
-	.section .data
-	.align 2
-flag_no_el3:
-	.long 0
diff --git a/arch/aarch64/boot.S b/arch/aarch64/boot.S
index 37759ce..fae0188 100644
--- a/arch/aarch64/boot.S
+++ b/arch/aarch64/boot.S
@@ -28,10 +28,6 @@ _start:
 	cmp	x0, #CURRENTEL_EL3
 	b.eq	1f
 
-	mov	w0, #1
-	ldr	x1, =flag_no_el3
-	str	w0, [x1]
-
 	b	start_no_el3
 
 1:	mov	x0, #0x30			// RES1
@@ -140,8 +136,8 @@ jump_kernel:
 	bl	find_logical_id
 	bl	setup_stack		// Reset stack pointer
 
-	ldr	w0, flag_no_el3
-	cmp	w0, #0			// Prepare Z flag
+	mrs	x0, CurrentEl
+	cmp	w0, #CURRENTEL_EL3	// Prepare Z flag
 
 	mov	x0, x20
 	mov	x1, x21
@@ -164,8 +160,3 @@ jump_kernel:
 	eret
 
 	.ltorg
-
-	.data
-	.align 3
-flag_no_el3:
-	.long 0
-- 
2.11.0


_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

  parent reply	other threads:[~2021-07-29 15:26 UTC|newest]

Thread overview: 27+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-07-29 15:20 [boot-wrapper PATCH 00/12] Preparatory fixes and cleanup Mark Rutland
2021-07-29 15:20 ` [boot-wrapper PATCH 01/12] Ensure `kernel_address` is aligned Mark Rutland
2021-07-30 15:11   ` Andre Przywara
2021-07-29 15:20 ` [boot-wrapper PATCH 02/12] Output text separately from data Mark Rutland
2021-07-29 15:20 ` [boot-wrapper PATCH 03/12] Remove cache maintenance Mark Rutland
2021-07-30 15:12   ` Andre Przywara
2021-07-30 15:43     ` Mark Rutland
2021-07-29 15:20 ` Mark Rutland [this message]
2021-07-30 15:13   ` [boot-wrapper PATCH 04/12] Remove `flag_no_el3` Andre Przywara
2021-07-30 16:43     ` Mark Rutland
2021-08-02 14:43       ` Mark Rutland
2021-07-29 15:20 ` [boot-wrapper PATCH 05/12] Move PSCI triage to C Mark Rutland
2021-07-29 15:20 ` [boot-wrapper PATCH 06/12] Move scripts to a `scripts` directory Mark Rutland
2021-07-30 15:13   ` Andre Przywara
2021-07-29 15:20 ` [boot-wrapper PATCH 07/12] aarch64: respect text offset Mark Rutland
2021-07-30 15:13   ` Andre Przywara
2021-07-30 15:43     ` Mark Rutland
2021-07-29 15:20 ` [boot-wrapper PATCH 08/12] Consistently use logical CPU IDs Mark Rutland
2021-07-30 17:38   ` Andre Przywara
2021-07-29 15:20 ` [boot-wrapper PATCH 09/12] Cleanup `.globl` usage Mark Rutland
2021-07-30 17:39   ` Andre Przywara
2021-07-29 15:20 ` [boot-wrapper PATCH 10/12] aarch32: rename `_spin_dead` -> `err_invalid_id` Mark Rutland
2021-07-30 17:39   ` Andre Przywara
2021-07-29 15:20 ` [boot-wrapper PATCH 11/12] Rename `spin.h` -> `boot.h` Mark Rutland
2021-07-30 17:39   ` Andre Przywara
2021-07-29 15:20 ` [boot-wrapper PATCH 12/12] Move common source files to `common` directory Mark Rutland
2021-07-30 17:40   ` Andre Przywara

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=20210729152050.23635-5-mark.rutland@arm.com \
    --to=mark.rutland@arm.com \
    --cc=Andre.Przywara@arm.com \
    --cc=Jaxson.Han@arm.com \
    --cc=Wei.Chen@arm.com \
    --cc=linux-arm-kernel@lists.infradead.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).