From cecf2db23b256d84ed54e1442b646f07373e5caa Mon Sep 17 00:00:00 2001
From: Akshay Saraswat <akshay.s@samsung.com>
Date: Fri, 20 Feb 2015 13:27:18 +0530
Subject: [PATCH] Exynos542x: Fix secondary core booting for thumb
When compiled SPL for Thumb secondary cores failed to boot
at the kernel boot up. Only one core came up out of 4.
This was happening because the code relocated to the
address 0x02073000 by the primary core was an ARM asm
code which was executed by the secondary cores as if it
was a thumb code.
This patch fixes the issue of secondary cores considering
relocated code as Thumb instructions and not ARM instructions
by jumping to the relocated with the help of "bx" ARM instruction.
"bx" instruction changes the 5th bit of CPSR which allows
execution unit to consider the following instructions as ARM
instructions.
Signed-off-by: Akshay Saraswat <akshay.s@samsung.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
Tested-by: Simon Glass <sjg@chromium.org>
Signed-off-by: Minkyu Kang <mk7.kang@samsung.com>
---
arch/arm/cpu/armv7/exynos/lowlevel_init.c | 2 +-
arch/arm/include/asm/arch-exynos/system.h | 3 +++
2 files changed, 4 insertions(+), 1 deletion(-)
diff --git a/arch/arm/cpu/armv7/exynos/lowlevel_init.c b/arch/arm/cpu/armv7/exynos/lowlevel_init.c
index 050457641e..782ecd1115 100644
--- a/arch/arm/cpu/armv7/exynos/lowlevel_init.c
+++ b/arch/arm/cpu/armv7/exynos/lowlevel_init.c
@@ -89,7 +89,7 @@ static void secondary_cpu_start(void)
{
v7_enable_smp(EXYNOS5420_INFORM_BASE);
svc32_mode_en();
- set_pc(CONFIG_EXYNOS_RELOCATE_CODE_BASE);
+ branch_bx(CONFIG_EXYNOS_RELOCATE_CODE_BASE);
}
/*
diff --git a/arch/arm/include/asm/arch-exynos/system.h b/arch/arm/include/asm/arch-exynos/system.h
index 86903c3696..a9fd5e6aa4 100644
--- a/arch/arm/include/asm/arch-exynos/system.h
+++ b/arch/arm/include/asm/arch-exynos/system.h
@@ -75,6 +75,9 @@ struct exynos5_sysreg {
/* Set program counter with the given value */
#define set_pc(x) __asm__ __volatile__ ("mov pc, %0\n\t" : : "r"(x))
+/* Branch to the given location */
+#define branch_bx(x) __asm__ __volatile__ ("bx %0\n\t" : : "r"(x))
+
/* Read Main Id register */
#define mrc_midr(x) __asm__ __volatile__ \
("mrc p15, 0, %0, c0, c0, 0\n\t" : "=r"(x) : )
--
2.39.5