[PATCH 08/12] ARM: head: use PC-relative insn sequence for __smp_alt

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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 08/12] ARM: head: use PC-relative insn sequence for __smp_alt
Date: Mon, 14 Sep 2020 12:57:02 +0300	[thread overview]
Message-ID: <20200914095706.3985-9-ardb@kernel.org> (raw)
In-Reply-To: <20200914095706.3985-1-ardb@kernel.org>

Now that calling __do_fixup_smp_on_up() can be done without passing
the physical-to-virtual offset in r3, we can replace the open coded
PC relative offset calculations 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 3199d29f4480..5f6436a40db1 100644
--- a/arch/arm/kernel/head.S
+++ b/arch/arm/kernel/head.S
@@ -520,19 +520,11 @@ ARM_BE8(rev	r0, r0)			@ byteswap if big endian
 	retne	lr
 
 __fixup_smp_on_up:
-	adr	r0, 1f
-	ldmia	r0, {r3 - r5}
-	sub	r3, r0, r3
-	add	r4, r4, r3
-	add	r5, r5, r3
+	adr_l	r4, __smpalt_begin
+	adr_l	r5, __smpalt_end
 	b	__do_fixup_smp_on_up
 ENDPROC(__fixup_smp)
 
-	.align
-1:	.word	.
-	.word	__smpalt_begin
-	.word	__smpalt_end
-
 	.pushsection .data
 	.align	2
 	.globl	smp_on_up
-- 
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 08/12] ARM: head: use PC-relative insn sequence for __smp_alt
Date: Mon, 14 Sep 2020 12:57:02 +0300	[thread overview]
Message-ID: <20200914095706.3985-9-ardb@kernel.org> (raw)
In-Reply-To: <20200914095706.3985-1-ardb@kernel.org>

Now that calling __do_fixup_smp_on_up() can be done without passing
the physical-to-virtual offset in r3, we can replace the open coded
PC relative offset calculations 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 3199d29f4480..5f6436a40db1 100644
--- a/arch/arm/kernel/head.S
+++ b/arch/arm/kernel/head.S
@@ -520,19 +520,11 @@ ARM_BE8(rev	r0, r0)			@ byteswap if big endian
 	retne	lr
 
 __fixup_smp_on_up:
-	adr	r0, 1f
-	ldmia	r0, {r3 - r5}
-	sub	r3, r0, r3
-	add	r4, r4, r3
-	add	r5, r5, r3
+	adr_l	r4, __smpalt_begin
+	adr_l	r5, __smpalt_end
 	b	__do_fixup_smp_on_up
 ENDPROC(__fixup_smp)
 
-	.align
-1:	.word	.
-	.word	__smpalt_begin
-	.word	__smpalt_end
-
 	.pushsection .data
 	.align	2
 	.globl	smp_on_up
-- 
2.17.1


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next prev parent reply	other threads:[~2020-09-14  9:58 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 ` [PATCH 05/12] ARM: head-common.S: use PC-relative insn sequence for idmap creation Ard Biesheuvel
2020-09-14  9:56   ` 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 ` Ard Biesheuvel [this message]
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 ` [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

find likely ancestor, descendant, or conflicting patches for this message:
( dfblob:3199d29f448 dfblob:5f6436a40db dfblob:3199d29f448
dfblob:5f6436a40db )
 OR (
bs:"[PATCH 08/12] ARM: head: use PC-relative insn sequence for __smp_alt" )
	(help)

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