sh: Fix up legacy PTEA space attribute mapping.
When p3_ioremap() was converted to ioremap_prot() there was some breakage
introduced where the 29-bit segmentation logic would trap the area range
and return an identity mapping without having allowed the area
specification to force mapping through page tables. This wires up a PCC
mask for pgprot verification to work out whether to short-circuit the
identity mapping on legacy parts, restoring the previous behaviour.
Reported-by: Nobuhiro Iwamatsu <iwamatsu@nigauri.org>
Cc: stable@kernel.org
Signed-off-by: Paul Mundt <lethal@linux-sh.org>
diff --git a/arch/sh/include/asm/io.h b/arch/sh/include/asm/io.h
index 70c1186..28c5aa5 100644
--- a/arch/sh/include/asm/io.h
+++ b/arch/sh/include/asm/io.h
@@ -290,7 +290,15 @@
* mapping must be done by the PMB or by using page tables.
*/
if (likely(PXSEG(offset) < P3SEG && PXSEG(last_addr) < P3SEG)) {
- if (unlikely(pgprot_val(prot) & _PAGE_CACHABLE))
+ u64 flags = pgprot_val(prot);
+
+ /*
+ * Anything using the legacy PTEA space attributes needs
+ * to be kicked down to page table mappings.
+ */
+ if (unlikely(flags & _PAGE_PCC_MASK))
+ return NULL;
+ if (unlikely(flags & _PAGE_CACHABLE))
return (void __iomem *)P1SEGADDR(offset);
return (void __iomem *)P2SEGADDR(offset);