On 11/02/2016 05:06 PM, Mark Rutland wrote:
On Wed, Nov 02, 2016 at 03:00:54PM -0600, Laura Abbott wrote:
+CFLAGS_physaddr.o := -DTEXT_OFFSET=$(TEXT_OFFSET)
+obj-$(CONFIG_DEBUG_VIRTUAL) += physaddr.o
diff --git a/arch/arm64/mm/physaddr.c b/arch/arm64/mm/physaddr.c
new file mode 100644
index 0000000..874c782
--- /dev/null
+++ b/arch/arm64/mm/physaddr.c
@@ -0,0 +1,34 @@
+#include <linux/mm.h>
+
+#include <asm/memory.h>
+
+unsigned long __virt_to_phys(unsigned long x)
+{
+ phys_addr_t __x = (phys_addr_t)x;
+
+ if (__x & BIT(VA_BITS - 1)) {
+ /*
+ * The linear kernel range starts in the middle of the virtual
+ * adddress space. Testing the top bit for the start of the
+ * region is a sufficient check.
+ */
+ return (__x & ~PAGE_OFFSET) + PHYS_OFFSET;
+ } else {
+ VIRTUAL_BUG_ON(x < kimage_vaddr || x >= (unsigned long)_end);
+ return (__x - kimage_voffset);
+ }
+}
+EXPORT_SYMBOL(__virt_to_phys);
+
+unsigned long __phys_addr_symbol(unsigned long x)
+{
+ phys_addr_t __x = (phys_addr_t)x;
+
+ /*
+ * This is intentionally different than above to be a tighter check
+ * for symbols.
+ */
+ VIRTUAL_BUG_ON(x < kimage_vaddr + TEXT_OFFSET || x > (unsigned long) _end);
Can't we use _text instead of kimage_vaddr + TEXT_OFFSET? That way we don't
need CFLAGS_physaddr.o.
Or KERNEL_START / KERNEL_END from <asm/memory.h>?
Otherwise, this looks good to me (though I haven't grokked the need for
__pa_symbol() yet).
I guess it's a question of what's clearer. I like kimage_vaddr +
TEXT_OFFSET because it clearly states we are checking from the
start of the kernel image vs. _text only shows the start of the
text region. Yes, it's technically the same but a little less
obvious. I suppose that could be solved with some more elaboration
in the comment.
Thanks,
Laura
Thanks,
Mark.
+ return (__x - kimage_voffset);
+}
+EXPORT_SYMBOL(__phys_addr_symbol);
--
2.10.1
--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@xxxxxxxxx. For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>