PPC: Don't sleep in flush_dcache_icache_page()

flush_dcache_icache_page() will be called on an instruction page fault. We can't sleep in the fault handler, so use kmap_atomic() instead of just kmap() for the Book-E case.

Signed-off-by Roland Dreier <[email protected]>

arch/ppc/mm/init.c +10 -2

@@ -560,8 +560,16 @@ void flush_dcache_page(struct page *page
 void flush_dcache_icache_page(struct page *page)
 {
 #ifdef CONFIG_BOOKE
-	__flush_dcache_icache(kmap(page));
-	kunmap(page);
+	unsigned long flags;
+	void *start;
+
+	local_irq_save(flags);
+
+	start = kmap_atomic(page, KM_PPC_SYNC_PAGE);
+	__flush_dcache_icache(start);
+	kunmap_atomic(start, KM_PPC_SYNC_PAGE);
+
+	local_irq_restore(flags);
 #elif CONFIG_8xx
 	/* On 8xx there is no need to kmap since highmem is not supported */
 	__flush_dcache_icache(page_address(page)); 

Hi Roland,

Quoted 4 lines · Roland Dreier

flush_dcache_icache_page() will be called on an instruction page fault. We can't sleep in the fault handler, so use kmap_atomic() instead of just kmap() for the Book-E case.

Quoted 1 line

Signed-off-by Roland Dreier <[email protected]>

Why do you need to disable interrupts during the kmap_atomic/flush_dcache_icache operation ?

I fail to see how an interrupt could have any reference to the data being dealt with here (the user page).