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>

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
 

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);
 }