RISC-V: Avoid corrupting the upper 32-bit of phys_addr_t in ioremap

Vincent Chen · palmer-dabbelt · commit 827a438156e4 · 2018-10-22T17:02:56.000-07:00
For 32bit, the upper 32-bit of phys_addr_t will be flushed to zero
after AND with PAGE_MASK because the data type of PAGE_MASK is
unsigned long. To fix this problem, the page alignment is done by
subtracting the page offset instead of AND with PAGE_MASK.

Signed-off-by: Vincent Chen &lt;vincentc@andestech.com&gt;
Reviewed-by: Christoph Hellwig &lt;hch@lst.de&gt;
Signed-off-by: Palmer Dabbelt &lt;palmer@sifive.com&gt;
diff --git a/arch/riscv/mm/ioremap.c b/arch/riscv/mm/ioremap.c
@@ -42,7 +42,7 @@ static void __iomem *__ioremap_caller(phys_addr_t addr, size_t size,
 
 	/* Page-align mappings */
 	offset = addr & (~PAGE_MASK);
-	addr &= PAGE_MASK;
+	addr -= offset;
 	size = PAGE_ALIGN(size + offset);
 
 	area = get_vm_area_caller(size, VM_IOREMAP, caller);
