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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 11/12] ARM: head.S: use PC relative insn sequence to calculate PHYS_OFFSET
Date: Mon, 14 Sep 2020 12:57:05 +0300	[thread overview]
Message-ID: <20200914095706.3985-12-ardb@kernel.org> (raw)
In-Reply-To: <20200914095706.3985-1-ardb@kernel.org>

Replace the open coded arithmetic with a simple adr_l/sub pair. 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 | 10 ++--------
 1 file changed, 2 insertions(+), 8 deletions(-)

diff --git a/arch/arm/kernel/head.S b/arch/arm/kernel/head.S
index 6f334df5d3b9..2e6127b2662e 100644
--- a/arch/arm/kernel/head.S
+++ b/arch/arm/kernel/head.S
@@ -103,10 +103,8 @@ ENTRY(stext)
 #endif
 
 #ifndef CONFIG_XIP_KERNEL
-	adr	r3, 2f
-	ldmia	r3, {r4, r8}
-	sub	r4, r3, r4			@ (PHYS_OFFSET - PAGE_OFFSET)
-	add	r8, r8, r4			@ PHYS_OFFSET
+	adr_l	r8, _text			@ __pa(_text)
+	sub	r8, r8, #TEXT_OFFSET		@ PHYS_OFFSET
 #else
 	ldr	r8, =PLAT_PHYS_OFFSET		@ always constant in this case
 #endif
@@ -158,10 +156,6 @@ ENTRY(stext)
 1:	b	__enable_mmu
 ENDPROC(stext)
 	.ltorg
-#ifndef CONFIG_XIP_KERNEL
-2:	.long	.
-	.long	PAGE_OFFSET
-#endif
 
 /*
  * Setup the initial page tables.  We only setup the barest
-- 
2.17.1


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  parent reply	other threads:[~2020-09-14 10:00 UTC|newest]

Thread overview: 31+ 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 ` [PATCH 01/12] ARM: assembler: introduce adr_l, ldr_l and str_l macros Ard Biesheuvel
2020-09-15  7:35   ` Ard Biesheuvel
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 ` [PATCH 03/12] ARM: module: add support for place relative relocations Ard Biesheuvel
2020-09-14 13:35   ` Nicolas Pitre
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 ` [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 ` [PATCH 07/12] ARM: kernel: use relative references for UP/SMP alternatives 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 ` [PATCH 09/12] ARM: sleep.S: use PC-relative insn sequence for sleep_save_sp/mpidr_hash 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 [this message]
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 14:06 ` [PATCH 00/12] ARM: use adr_l/ldr_l macros for PC-relative references Nicolas Pitre
2020-09-15 19:32 ` Nick Desaulniers
2020-09-15 21:29   ` Ard Biesheuvel
2020-09-15 23:31     ` Nick Desaulniers
2020-09-16  5:54       ` Ard Biesheuvel
2020-09-16 19:53         ` Nick Desaulniers
2020-09-16 20:45           ` Ard Biesheuvel
2020-09-16 21:25             ` Nick Desaulniers
2020-09-17  0:16               ` Nick Desaulniers
2020-09-17  5:19                 ` Mike Rapoport
2020-09-17  6:01               ` Ard Biesheuvel
2020-09-18 20:03                 ` Nick Desaulniers
2020-09-18 20:44                   ` Ard Biesheuvel
2020-09-18 21:06                     ` Nick Desaulniers

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