ARM: EXYNOS: Don't use LDREX and STREX after disabling cache coherency

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@codeaurora.org>
Signed-off-by: Krzysztof Kozlowski <k.kozlowski@samsung.com>
Reviewed-by: Stephen Boyd <sboyd@codeaurora.org>
Signed-off-by: Kukjin Kim <kgene@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/arch/arm/mach-exynos/platsmp.c b/arch/arm/mach-exynos/platsmp.c
index 7a1ebfeeeeb8cf01ffff3494b0162db36c91d7af..0abb7dff73ab8f669d98cd8a9db1bef36e65af22 100644 (file)
--- a/arch/arm/mach-exynos/platsmp.c
+++ b/arch/arm/mach-exynos/platsmp.c
@@ -126,8 +126,7 @@ static inline void platform_do_lowpower(unsigned int cpu, int *spurious)
  */
 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