[PATCH 1/2] ARM: Add a secondary_startup that assumes ARM mode

From: Stephen Boyd
Date: Wed Jan 21 2015 - 14:48:51 EST


Some platforms always enter the kernel in ARM mode even if the
kernel is compiled for THUMB2. Add a small wrapper on top of
secondary_startup() that switches into THUMB2 mode.

Signed-off-by: Stephen Boyd <sboyd@xxxxxxxxxxxxxx>
---
arch/arm/kernel/head.S | 7 +++++++
1 file changed, 7 insertions(+)

diff --git a/arch/arm/kernel/head.S b/arch/arm/kernel/head.S
index 664eee8c4a26..22bb6d54e90d 100644
--- a/arch/arm/kernel/head.S
+++ b/arch/arm/kernel/head.S
@@ -346,6 +346,12 @@ __turn_mmu_on_loc:

#if defined(CONFIG_SMP)
.text
+ENTRY(secondary_startup_arm)
+ .arm
+ THUMB( adr r9, BSYM(1f) ) @ Kernel is entered in ARM.
+ THUMB( bx r9 ) @ If this is a Thumb-2 kernel,
+ THUMB( .thumb ) @ switch to Thumb now.
+ THUMB(1: )
ENTRY(secondary_startup)
/*
* Common entry point for secondary CPUs.
@@ -385,6 +391,7 @@ ENTRY(secondary_startup)
THUMB( add r12, r10, #PROCINFO_INITFUNC )
THUMB( ret r12 )
ENDPROC(secondary_startup)
+ENDPROC(secondary_startup_arm)

/*
* r6 = &secondary_data
--
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a Linux Foundation Collaborative Project

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