powerpc/85xx: flush dcache before resetting cores

When we do an mpic_reset_core we need to make sure the dcache is flushed.
Signed-off-by: Matthew McClintock <msm@freescale.com>
Signed-off-by: Kumar Gala <galak@kernel.crashing.org>

arch/powerpc/platforms/85xx/smp.c

@@ -16,6 +16,7 @@
 #include <linux/delay.h>
 #include <linux/of.h>
 #include <linux/kexec.h>
+#include <linux/highmem.h>
 
 #include <asm/machdep.h>
 #include <asm/pgtable.h>
@@ -140,11 +141,60 @@ static void mpc85xx_smp_kexec_down(void *arg)
 		ppc_md.kexec_cpu_down(0,1);
 }
 
+static void map_and_flush(unsigned long paddr)
+{
+	struct page *page = pfn_to_page(paddr >> PAGE_SHIFT);
+	unsigned long kaddr  = (unsigned long)kmap(page);
+
+	flush_dcache_range(kaddr, kaddr + PAGE_SIZE);
+	kunmap(page);
+}
+
+/**
+ * Before we reset the other cores, we need to flush relevant cache
+ * out to memory so we don't get anything corrupted, some of these flushes
+ * are performed out of an overabundance of caution as interrupts are not
+ * disabled yet and we can switch cores
+ */
+static void mpc85xx_smp_flush_dcache_kexec(struct kimage *image)
+{
+	kimage_entry_t *ptr, entry;
+	unsigned long paddr;
+	int i;
+
+	if (image->type == KEXEC_TYPE_DEFAULT) {
+		/* normal kexec images are stored in temporary pages */
+		for (ptr = &image->head; (entry = *ptr) && !(entry & IND_DONE);
+		     ptr = (entry & IND_INDIRECTION) ?
+				phys_to_virt(entry & PAGE_MASK) : ptr + 1) {
+			if (!(entry & IND_DESTINATION)) {
+				map_and_flush(entry);
+			}
+		}
+		/* flush out last IND_DONE page */
+		map_and_flush(entry);
+	} else {
+		/* crash type kexec images are copied to the crash region */
+		for (i = 0; i < image->nr_segments; i++) {
+			struct kexec_segment *seg = &image->segment[i];
+			for (paddr = seg->mem; paddr < seg->mem + seg->memsz;
+			     paddr += PAGE_SIZE) {
+				map_and_flush(paddr);
+			}
+		}
+	}
+
+	/* also flush the kimage struct to be passed in as well */
+	flush_dcache_range((unsigned long)image,
+			   (unsigned long)image + sizeof(*image));
+}
+
 static void mpc85xx_smp_machine_kexec(struct kimage *image)
 {
 	int timeout = INT_MAX;
 	int i, num_cpus = num_present_cpus();
 
+	mpc85xx_smp_flush_dcache_kexec(image);
 
 	if (image->type == KEXEC_TYPE_DEFAULT)
 		smp_call_function(mpc85xx_smp_kexec_down, NULL, 0);