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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 10/12] ARM: head.S: use PC-relative insn sequences for __fixup_pv_table
Date: Mon, 14 Sep 2020 12:57:04 +0300	[thread overview]
Message-ID: <20200914095706.3985-11-ardb@kernel.org> (raw)
In-Reply-To: <20200914095706.3985-1-ardb@kernel.org>

Replace the open coded PC relative offset calculations with adr_l
and mov_l invocations. This removes some open coded arithmetic involving
virtual addresses and avoids literal pools on v7+. Note that the footprint
of the code increases slightly, but the resulting code is a bit easier to
follow.

Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
---
 arch/arm/kernel/head.S | 27 ++++++--------------
 1 file changed, 8 insertions(+), 19 deletions(-)

diff --git a/arch/arm/kernel/head.S b/arch/arm/kernel/head.S
index 5f6436a40db1..6f334df5d3b9 100644
--- a/arch/arm/kernel/head.S
+++ b/arch/arm/kernel/head.S
@@ -576,14 +576,11 @@ ENDPROC(fixup_smp)
  */
 	__HEAD
 __fixup_pv_table:
-	adr	r0, 1f
-	ldmia	r0, {r3-r7}
+	adr_l	r6, __pv_phys_pfn_offset
+	adr_l	r7, __pv_offset			@ __pa(__pv_offset)
+	mov_l	r3, __pv_offset			@ __va(__pv_offset)
 	mvn	ip, #0
-	subs	r3, r0, r3	@ PHYS_OFFSET - PAGE_OFFSET
-	add	r4, r4, r3	@ adjust table start address
-	add	r5, r5, r3	@ adjust table end address
-	add	r6, r6, r3	@ adjust __pv_phys_pfn_offset address
-	add	r7, r7, r3	@ adjust __pv_offset address
+	subs	r3, r7, r3	@ PHYS_OFFSET - PAGE_OFFSET
 	mov	r0, r8, lsr #PAGE_SHIFT	@ convert to PFN
 	str	r0, [r6]	@ save computed PHYS_OFFSET to __pv_phys_pfn_offset
 	strcc	ip, [r7, #HIGH_OFFSET]	@ save to __pv_offset high bits
@@ -592,20 +589,15 @@ __fixup_pv_table:
 THUMB(	it	ne		@ cross section branch )
 	bne	__error
 	str	r3, [r7, #LOW_OFFSET]	@ save to __pv_offset low bits
+	adr_l	r4, __pv_table_begin
+	adr_l	r5, __pv_table_end
 	b	__fixup_a_pv_table
 ENDPROC(__fixup_pv_table)
-
-	.align
-1:	.long	.
-	.long	__pv_table_begin
-	.long	__pv_table_end
-2:	.long	__pv_phys_pfn_offset
-	.long	__pv_offset
+	.ltorg
 
 	.text
 __fixup_a_pv_table:
-	adr	r0, 3f
-	ldr	r6, [r0]
+	mov_l	r6, __pv_offset
 	add	r6, r6, r3
 	ldr	r0, [r6, #HIGH_OFFSET]	@ pv_offset high word
 	ldr	r6, [r6, #LOW_OFFSET]	@ pv_offset low word
@@ -674,9 +666,6 @@ ARM_BE8(rev16	ip, ip)
 #endif
 ENDPROC(__fixup_a_pv_table)
 
-	.align
-3:	.long __pv_offset
-
 ENTRY(fixup_pv_table)
 	stmfd	sp!, {r4 - r7, lr}
 	mov	r3, #0			@ no offset
-- 
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 10/12] ARM: head.S: use PC-relative insn sequences for __fixup_pv_table
Date: Mon, 14 Sep 2020 12:57:04 +0300	[thread overview]
Message-ID: <20200914095706.3985-11-ardb@kernel.org> (raw)
In-Reply-To: <20200914095706.3985-1-ardb@kernel.org>

Replace the open coded PC relative offset calculations with adr_l
and mov_l invocations. This removes some open coded arithmetic involving
virtual addresses and avoids literal pools on v7+. Note that the footprint
of the code increases slightly, but the resulting code is a bit easier to
follow.

Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
---
 arch/arm/kernel/head.S | 27 ++++++--------------
 1 file changed, 8 insertions(+), 19 deletions(-)

diff --git a/arch/arm/kernel/head.S b/arch/arm/kernel/head.S
index 5f6436a40db1..6f334df5d3b9 100644
--- a/arch/arm/kernel/head.S
+++ b/arch/arm/kernel/head.S
@@ -576,14 +576,11 @@ ENDPROC(fixup_smp)
  */
 	__HEAD
 __fixup_pv_table:
-	adr	r0, 1f
-	ldmia	r0, {r3-r7}
+	adr_l	r6, __pv_phys_pfn_offset
+	adr_l	r7, __pv_offset			@ __pa(__pv_offset)
+	mov_l	r3, __pv_offset			@ __va(__pv_offset)
 	mvn	ip, #0
-	subs	r3, r0, r3	@ PHYS_OFFSET - PAGE_OFFSET
-	add	r4, r4, r3	@ adjust table start address
-	add	r5, r5, r3	@ adjust table end address
-	add	r6, r6, r3	@ adjust __pv_phys_pfn_offset address
-	add	r7, r7, r3	@ adjust __pv_offset address
+	subs	r3, r7, r3	@ PHYS_OFFSET - PAGE_OFFSET
 	mov	r0, r8, lsr #PAGE_SHIFT	@ convert to PFN
 	str	r0, [r6]	@ save computed PHYS_OFFSET to __pv_phys_pfn_offset
 	strcc	ip, [r7, #HIGH_OFFSET]	@ save to __pv_offset high bits
@@ -592,20 +589,15 @@ __fixup_pv_table:
 THUMB(	it	ne		@ cross section branch )
 	bne	__error
 	str	r3, [r7, #LOW_OFFSET]	@ save to __pv_offset low bits
+	adr_l	r4, __pv_table_begin
+	adr_l	r5, __pv_table_end
 	b	__fixup_a_pv_table
 ENDPROC(__fixup_pv_table)
-
-	.align
-1:	.long	.
-	.long	__pv_table_begin
-	.long	__pv_table_end
-2:	.long	__pv_phys_pfn_offset
-	.long	__pv_offset
+	.ltorg
 
 	.text
 __fixup_a_pv_table:
-	adr	r0, 3f
-	ldr	r6, [r0]
+	mov_l	r6, __pv_offset
 	add	r6, r6, r3
 	ldr	r0, [r6, #HIGH_OFFSET]	@ pv_offset high word
 	ldr	r6, [r6, #LOW_OFFSET]	@ pv_offset low word
@@ -674,9 +666,6 @@ ARM_BE8(rev16	ip, ip)
 #endif
 ENDPROC(__fixup_a_pv_table)
 
-	.align
-3:	.long __pv_offset
-
 ENTRY(fixup_pv_table)
 	stmfd	sp!, {r4 - r7, lr}
 	mov	r3, #0			@ no offset
-- 
2.17.1


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  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 ` [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 ` Ard Biesheuvel [this message]
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 ` [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

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