ARM: 8640/1: Add support for CONFIG_DEBUG_VIRTUAL
x86 has an option: CONFIG_DEBUG_VIRTUAL to do additional checks on
virt_to_phys calls. The goal is to catch users who are calling
virt_to_phys on non-linear addresses immediately. This includes caller
using __virt_to_phys() on image addresses instead of __pa_symbol(). This
is a generally useful debug feature to spot bad code (particulary in
drivers).
Acked-by: Russell King <rmk+kernel@armlinux.org.uk>
Acked-by: Laura Abbott <labbott@redhat.com>
Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
diff --git a/arch/arm/mm/physaddr.c b/arch/arm/mm/physaddr.c
new file mode 100644
index 0000000..02e60f4
--- /dev/null
+++ b/arch/arm/mm/physaddr.c
@@ -0,0 +1,57 @@
+#include <linux/bug.h>
+#include <linux/export.h>
+#include <linux/types.h>
+#include <linux/mmdebug.h>
+#include <linux/mm.h>
+
+#include <asm/sections.h>
+#include <asm/memory.h>
+#include <asm/fixmap.h>
+#include <asm/dma.h>
+
+#include "mm.h"
+
+static inline bool __virt_addr_valid(unsigned long x)
+{
+ /*
+ * high_memory does not get immediately defined, and there
+ * are early callers of __pa() against PAGE_OFFSET
+ */
+ if (!high_memory && x >= PAGE_OFFSET)
+ return true;
+
+ if (high_memory && x >= PAGE_OFFSET && x < (unsigned long)high_memory)
+ return true;
+
+ /*
+ * MAX_DMA_ADDRESS is a virtual address that may not correspond to an
+ * actual physical address. Enough code relies on __pa(MAX_DMA_ADDRESS)
+ * that we just need to work around it and always return true.
+ */
+ if (x == MAX_DMA_ADDRESS)
+ return true;
+
+ return false;
+}
+
+phys_addr_t __virt_to_phys(unsigned long x)
+{
+ WARN(!__virt_addr_valid(x),
+ "virt_to_phys used for non-linear address: %pK (%pS)\n",
+ (void *)x, (void *)x);
+
+ return __virt_to_phys_nodebug(x);
+}
+EXPORT_SYMBOL(__virt_to_phys);
+
+phys_addr_t __phys_addr_symbol(unsigned long x)
+{
+ /* This is bounds checking against the kernel image only.
+ * __pa_symbol should only be used on kernel symbol addresses.
+ */
+ VIRTUAL_BUG_ON(x < (unsigned long)KERNEL_START ||
+ x > (unsigned long)KERNEL_END);
+
+ return __pa_symbol_nodebug(x);
+}
+EXPORT_SYMBOL(__phys_addr_symbol);