arm: Disable outer (L2) cache in kexec

kexec does not disable the outer cache before disabling the inner
caches in cpu_proc_fin(). So L2 is enabled across the kexec jump. When
the new kernel enables chaches again, it randomly crashes.

Disabling L2 before calling cpu_proc_fin() cures the problem.

Disabling L2 requires the following new functions: flush_all(),
inv_all() and disable(). Add them to outer_cache_fns and call them
from the kexec code.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Acked-by: Linus Walleij <linus.walleij@stericsson.com>

2 files changed, 27 insertions, 0 deletions

diff --git a/arch/arm/include/asm/outercache.h b/arch/arm/include/asm/outercache.h
index 25f76bae57a..fc190092527 100644
--- a/arch/arm/include/asm/outercache.h
+++ b/arch/arm/include/asm/outercache.h
@@ -25,6 +25,9 @@ struct outer_cache_fns {
         void (*inv_range)(unsigned long, unsigned long);
         void (*clean_range)(unsigned long, unsigned long);
         void (*flush_range)(unsigned long, unsigned long);
+        void (*flush_all)(void);
+        void (*inv_all)(void);
+        void (*disable)(void);
 #ifdef CONFIG_OUTER_CACHE_SYNC
         void (*sync)(void);
 #endif
@@ -50,6 +53,24 @@ static inline void outer_flush_range(unsigned long start, unsigned long end)
                 outer_cache.flush_range(start, end);
 }
 
+static inline void outer_flush_all(void)
+{
+        if (outer_cache.flush_all)
+                outer_cache.flush_all();
+}
+
+static inline void outer_inv_all(void)
+{
+        if (outer_cache.inv_all)
+                outer_cache.inv_all();
+}
+
+static inline void outer_disable(void)
+{
+        if (outer_cache.disable)
+                outer_cache.disable();
+}
+
 #else
 
 static inline void outer_inv_range(unsigned long start, unsigned long end)
@@ -58,6 +79,9 @@ static inline void outer_clean_range(unsigned long start, unsigned long end)
 { }
 static inline void outer_flush_range(unsigned long start, unsigned long end)
 { }
+static inline void outer_flush_all(void) { }
+static inline void outer_inv_all(void) { }
+static inline void outer_disable(void) { }
 
 #endif
 
diff --git a/arch/arm/kernel/machine_kexec.c b/arch/arm/kernel/machine_kexec.c
index 1fc74cbd1a1..3a8fd5140d7 100644
--- a/arch/arm/kernel/machine_kexec.c
+++ b/arch/arm/kernel/machine_kexec.c
@@ -78,7 +78,10 @@ void machine_kexec(struct kimage *image)
         local_fiq_disable();
         setup_mm_for_reboot(0); /* mode is not used, so just pass 0*/
         flush_cache_all();
+        outer_flush_all();
+        outer_disable();
         cpu_proc_fin();
+        outer_inv_all();
         flush_cache_all();
         cpu_reset(reboot_code_buffer_phys);
 }