ARM: relax ioremap prohibition (309caa9) for -final and -stable
Russell King [Tue, 12 Oct 2010 23:15:25 +0000 (00:15 +0100)]
... but produce a big warning about the problem as encouragement
for people to fix their drivers.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

arch/arm/mm/ioremap.c

index ab50627..17e7b0b 100644 (file)
@@ -204,8 +204,12 @@ void __iomem * __arm_ioremap_pfn_caller(unsigned long pfn,
        /*
         * Don't allow RAM to be mapped - this causes problems with ARMv6+
         */
-       if (WARN_ON(pfn_valid(pfn)))
-               return NULL;
+       if (pfn_valid(pfn)) {
+               printk(KERN_WARNING "BUG: Your driver calls ioremap() on system memory.  This leads\n"
+                      KERN_WARNING "to architecturally unpredictable behaviour on ARMv6+, and ioremap()\n"
+                      KERN_WARNING "will fail in the next kernel release.  Please fix your driver.\n");
+               WARN_ON(1);
+       }
 
        type = get_mem_type(mtype);
        if (!type)