[PATCH 3.19 114/123] ARM: EXYNOS: Dont use LDREX and STREX after disabling cache coherency

[Greg Kroah-Hartman]

3.19-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Krzysztof Kozlowski <k.kozlowski@xxxxxxxxxxx>

commit ca489c58ef0b81cc9c9252fd92e6c9bb38d3c408 upstream.

During CPU shutdown the exynos_cpu_power_down() is called after
disabling cache coherency and it uses LDREX and STREX instructions (by
calling of_machine_is_compatible() -> kobject_get() -> kref_get()).

The LDREX and STREX should not be used after disabling the cache
coherency so just use soc_is_exynos().

Fixes: adc548d77c22 ("ARM: EXYNOS: Use MCPM call-backs to support S2R
on exynos5420")

Reported-by: Stephen Boyd <sboyd@xxxxxxxxxxxxxx>
Signed-off-by: Krzysztof Kozlowski <k.kozlowski@xxxxxxxxxxx>
Reviewed-by: Stephen Boyd <sboyd@xxxxxxxxxxxxxx>
Signed-off-by: Kukjin Kim <kgene@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
 arch/arm/mach-exynos/platsmp.c |    3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

--- a/arch/arm/mach-exynos/platsmp.c
+++ b/arch/arm/mach-exynos/platsmp.c
@@ -126,8 +126,7 @@ static inline void platform_do_lowpower(
  */
 void exynos_cpu_power_down(int cpu)
 {
-	if (cpu == 0 && (of_machine_is_compatible("samsung,exynos5420") ||
-		of_machine_is_compatible("samsung,exynos5800"))) {
+	if (cpu == 0 && (soc_is_exynos5420() || soc_is_exynos5800())) {
 		/*
 		 * Bypass power down for CPU0 during suspend. Check for
 		 * the SYS_PWR_REG value to decide if we are suspending


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