From: Ard Biesheuvel <ardb@kernel.org>
Date: Mon, 14 Sep 2020 08:25:46 +0000 (+0300)
Subject: ARM: head.S: use PC relative insn sequence to calculate PHYS_OFFSET
X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=3bcf906b194cebb6817cbb2f07b69e12aa5d7f51;p=linux.git

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
removes some open coded arithmetic involving virtual addresses, avoids
literal pools on v7+, and slightly reduces the footprint of the code.

Reviewed-by: Nicolas Pitre <nico@fluxnic.net>
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
---

diff --git a/arch/arm/kernel/head.S b/arch/arm/kernel/head.S
index 5e031a0bf9a96..ae0b08b47f52c 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