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Message-Id: <20170903120757.14968-12-ard.biesheuvel@linaro.org>
Date: Sun, 3 Sep 2017 13:07:39 +0100
From: Ard Biesheuvel <ard.biesheuvel@...aro.org>
To: linux-arm-kernel@...ts.infradead.org,
kernel-hardening@...ts.openwall.com
Cc: Ard Biesheuvel <ard.biesheuvel@...aro.org>,
Arnd Bergmann <arnd@...db.de>,
Nicolas Pitre <nico@...aro.org>,
Russell King <linux@...linux.org.uk>,
Kees Cook <keescook@...omium.org>,
Thomas Garnier <thgarnie@...gle.com>,
Marc Zyngier <marc.zyngier@....com>,
Mark Rutland <mark.rutland@....com>,
Tony Lindgren <tony@...mide.com>,
Matt Fleming <matt@...eblueprint.co.uk>,
Dave Martin <dave.martin@....com>
Subject: [PATCH v2 11/29] ARM: head.S: use PC relative insn sequence to calculate PHYS_OFFSET
Replace the open coded arithmetic with a simple adr_l/sub pair. This
ensures these quantities are invariant under runtime relocation.
Cc: Russell King <linux@...linux.org.uk>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@...aro.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 f607e290ef4b..62c961849035 100644
--- a/arch/arm/kernel/head.S
+++ b/arch/arm/kernel/head.S
@@ -106,10 +106,8 @@ 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
@@ -161,10 +159,6 @@ 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
--
2.11.0
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