All of lore.kernel.org
 help / color / mirror / Atom feed
From: Ard Biesheuvel <ardb@kernel.org>
To: linux-efi@vger.kernel.org
Cc: linux-arm-kernel@lists.infradead.org,
	Ard Biesheuvel <ardb@kernel.org>,
	Russell King <linux@armlinux.org.uk>,
	Linus Walleij <linus.walleij@linaro.org>,
	Nicolas Pitre <nico@fluxnic.net>,
	Nick Desaulniers <ndesaulniers@google.com>,
	Stefan Agner <stefan@agner.ch>, Peter Smith <Peter.Smith@arm.com>,
	Marc Zyngier <maz@kernel.org>, Will Deacon <will@kernel.org>
Subject: [PATCH 05/12] ARM: head-common.S: use PC-relative insn sequence for idmap creation
Date: Mon, 14 Sep 2020 12:56:59 +0300	[thread overview]
Message-ID: <20200914095706.3985-6-ardb@kernel.org> (raw)
In-Reply-To: <20200914095706.3985-1-ardb@kernel.org>

Replace the open coded PC relative offset calculations involving
__turn_mmu_on and __turn_mmu_on_end with a pair of adr_l invocations.
This removes some open coded arithmetic involving virtual addresses,
avoids literal pools on v7+, and slightly reduces the footprint of the
code.

Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
---
 arch/arm/kernel/head.S | 12 ++----------
 1 file changed, 2 insertions(+), 10 deletions(-)

diff --git a/arch/arm/kernel/head.S b/arch/arm/kernel/head.S
index f8904227e7fd..7d8e2a296216 100644
--- a/arch/arm/kernel/head.S
+++ b/arch/arm/kernel/head.S
@@ -224,11 +224,8 @@ __create_page_tables:
 	 * Create identity mapping to cater for __enable_mmu.
 	 * This identity mapping will be removed by paging_init().
 	 */
-	adr	r0, __turn_mmu_on_loc
-	ldmia	r0, {r3, r5, r6}
-	sub	r0, r0, r3			@ virt->phys offset
-	add	r5, r5, r0			@ phys __turn_mmu_on
-	add	r6, r6, r0			@ phys __turn_mmu_on_end
+	adr_l	r5, __turn_mmu_on		@ _pa(__turn_mmu_on)
+	adr_l	r6, __turn_mmu_on_end		@ _pa(__turn_mmu_on_end)
 	mov	r5, r5, lsr #SECTION_SHIFT
 	mov	r6, r6, lsr #SECTION_SHIFT
 
@@ -351,11 +348,6 @@ __create_page_tables:
 	ret	lr
 ENDPROC(__create_page_tables)
 	.ltorg
-	.align
-__turn_mmu_on_loc:
-	.long	.
-	.long	__turn_mmu_on
-	.long	__turn_mmu_on_end
 
 #if defined(CONFIG_SMP)
 	.text
-- 
2.17.1


WARNING: multiple messages have this Message-ID (diff)
From: Ard Biesheuvel <ardb@kernel.org>
To: linux-efi@vger.kernel.org
Cc: Nicolas Pitre <nico@fluxnic.net>, Marc Zyngier <maz@kernel.org>,
	Linus Walleij <linus.walleij@linaro.org>,
	Nick Desaulniers <ndesaulniers@google.com>,
	Russell King <linux@armlinux.org.uk>,
	Stefan Agner <stefan@agner.ch>, Peter Smith <Peter.Smith@arm.com>,
	Will Deacon <will@kernel.org>, Ard Biesheuvel <ardb@kernel.org>,
	linux-arm-kernel@lists.infradead.org
Subject: [PATCH 05/12] ARM: head-common.S: use PC-relative insn sequence for idmap creation
Date: Mon, 14 Sep 2020 12:56:59 +0300	[thread overview]
Message-ID: <20200914095706.3985-6-ardb@kernel.org> (raw)
In-Reply-To: <20200914095706.3985-1-ardb@kernel.org>

Replace the open coded PC relative offset calculations involving
__turn_mmu_on and __turn_mmu_on_end with a pair of adr_l invocations.
This removes some open coded arithmetic involving virtual addresses,
avoids literal pools on v7+, and slightly reduces the footprint of the
code.

Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
---
 arch/arm/kernel/head.S | 12 ++----------
 1 file changed, 2 insertions(+), 10 deletions(-)

diff --git a/arch/arm/kernel/head.S b/arch/arm/kernel/head.S
index f8904227e7fd..7d8e2a296216 100644
--- a/arch/arm/kernel/head.S
+++ b/arch/arm/kernel/head.S
@@ -224,11 +224,8 @@ __create_page_tables:
 	 * Create identity mapping to cater for __enable_mmu.
 	 * This identity mapping will be removed by paging_init().
 	 */
-	adr	r0, __turn_mmu_on_loc
-	ldmia	r0, {r3, r5, r6}
-	sub	r0, r0, r3			@ virt->phys offset
-	add	r5, r5, r0			@ phys __turn_mmu_on
-	add	r6, r6, r0			@ phys __turn_mmu_on_end
+	adr_l	r5, __turn_mmu_on		@ _pa(__turn_mmu_on)
+	adr_l	r6, __turn_mmu_on_end		@ _pa(__turn_mmu_on_end)
 	mov	r5, r5, lsr #SECTION_SHIFT
 	mov	r6, r6, lsr #SECTION_SHIFT
 
@@ -351,11 +348,6 @@ __create_page_tables:
 	ret	lr
 ENDPROC(__create_page_tables)
 	.ltorg
-	.align
-__turn_mmu_on_loc:
-	.long	.
-	.long	__turn_mmu_on
-	.long	__turn_mmu_on_end
 
 #if defined(CONFIG_SMP)
 	.text
-- 
2.17.1


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

  parent reply	other threads:[~2020-09-14  9:57 UTC|newest]

Thread overview: 62+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-09-14  9:56 [PATCH 00/12] ARM: use adr_l/ldr_l macros for PC-relative references Ard Biesheuvel
2020-09-14  9:56 ` Ard Biesheuvel
2020-09-14  9:56 ` [PATCH 01/12] ARM: assembler: introduce adr_l, ldr_l and str_l macros Ard Biesheuvel
2020-09-14  9:56   ` Ard Biesheuvel
2020-09-15  7:35   ` Ard Biesheuvel
2020-09-15  7:35     ` Ard Biesheuvel
2020-09-15 17:51     ` Nick Desaulniers
2020-09-15 17:51       ` Nick Desaulniers
2020-09-14  9:56 ` [PATCH 02/12] ARM: efistub: replace adrl pseudo-op with adr_l macro invocation Ard Biesheuvel
2020-09-14  9:56   ` Ard Biesheuvel
2020-09-14  9:56 ` [PATCH 03/12] ARM: module: add support for place relative relocations Ard Biesheuvel
2020-09-14  9:56   ` Ard Biesheuvel
2020-09-14 13:35   ` Nicolas Pitre
2020-09-14 13:35     ` Nicolas Pitre
2020-09-14 16:11     ` Russell King - ARM Linux admin
2020-09-14 16:11       ` Russell King - ARM Linux admin
2020-09-14  9:56 ` [PATCH 04/12] ARM: head-common.S: use PC-relative insn sequence for __proc_info Ard Biesheuvel
2020-09-14  9:56   ` Ard Biesheuvel
2020-09-14  9:56 ` Ard Biesheuvel [this message]
2020-09-14  9:56   ` [PATCH 05/12] ARM: head-common.S: use PC-relative insn sequence for idmap creation Ard Biesheuvel
2020-09-14  9:57 ` [PATCH 06/12] ARM: head.S: use PC-relative insn sequence for secondary_data Ard Biesheuvel
2020-09-14  9:57   ` Ard Biesheuvel
2020-09-14  9:57 ` [PATCH 07/12] ARM: kernel: use relative references for UP/SMP alternatives Ard Biesheuvel
2020-09-14  9:57   ` Ard Biesheuvel
2020-09-14  9:57 ` [PATCH 08/12] ARM: head: use PC-relative insn sequence for __smp_alt Ard Biesheuvel
2020-09-14  9:57   ` Ard Biesheuvel
2020-09-14  9:57 ` [PATCH 09/12] ARM: sleep.S: use PC-relative insn sequence for sleep_save_sp/mpidr_hash Ard Biesheuvel
2020-09-14  9:57   ` Ard Biesheuvel
2020-09-14  9:57 ` [PATCH 10/12] ARM: head.S: use PC-relative insn sequences for __fixup_pv_table Ard Biesheuvel
2020-09-14  9:57   ` Ard Biesheuvel
2020-09-14  9:57 ` [PATCH 11/12] ARM: head.S: use PC relative insn sequence to calculate PHYS_OFFSET Ard Biesheuvel
2020-09-14  9:57   ` Ard Biesheuvel
2020-09-14  9:57 ` [PATCH 12/12] ARM: kvm: replace open coded VA->PA calculations with adr_l call Ard Biesheuvel
2020-09-14  9:57   ` Ard Biesheuvel
2020-09-14 14:06 ` [PATCH 00/12] ARM: use adr_l/ldr_l macros for PC-relative references Nicolas Pitre
2020-09-14 14:06   ` Nicolas Pitre
2020-09-15 19:32 ` Nick Desaulniers
2020-09-15 19:32   ` Nick Desaulniers
2020-09-15 21:29   ` Ard Biesheuvel
2020-09-15 21:29     ` Ard Biesheuvel
2020-09-15 23:31     ` Nick Desaulniers
2020-09-15 23:31       ` Nick Desaulniers
2020-09-16  5:54       ` Ard Biesheuvel
2020-09-16  5:54         ` Ard Biesheuvel
2020-09-16 19:53         ` Nick Desaulniers
2020-09-16 19:53           ` Nick Desaulniers
2020-09-16 20:45           ` Ard Biesheuvel
2020-09-16 20:45             ` Ard Biesheuvel
2020-09-16 21:25             ` Nick Desaulniers
2020-09-16 21:25               ` Nick Desaulniers
2020-09-17  0:16               ` Nick Desaulniers
2020-09-17  0:16                 ` Nick Desaulniers
2020-09-17  5:19                 ` Mike Rapoport
2020-09-17  5:19                   ` Mike Rapoport
2020-09-17  6:01               ` Ard Biesheuvel
2020-09-17  6:01                 ` Ard Biesheuvel
2020-09-18 20:03                 ` Nick Desaulniers
2020-09-18 20:03                   ` Nick Desaulniers
2020-09-18 20:44                   ` Ard Biesheuvel
2020-09-18 20:44                     ` Ard Biesheuvel
2020-09-18 21:06                     ` Nick Desaulniers
2020-09-18 21:06                       ` Nick Desaulniers

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=20200914095706.3985-6-ardb@kernel.org \
    --to=ardb@kernel.org \
    --cc=Peter.Smith@arm.com \
    --cc=linus.walleij@linaro.org \
    --cc=linux-arm-kernel@lists.infradead.org \
    --cc=linux-efi@vger.kernel.org \
    --cc=linux@armlinux.org.uk \
    --cc=maz@kernel.org \
    --cc=ndesaulniers@google.com \
    --cc=nico@fluxnic.net \
    --cc=stefan@agner.ch \
    --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 an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.