libfdt: Check for 8-byte address alignment in fdt_ro_probe_()

The device tree must be loaded in to memory at an 8-byte aligned address. Add a check for this condition in fdt_ro_probe_() and a new error code to return if we are not. Signed-off-by: Tom Rini <[email protected]> Message-Id: <[email protected]> Signed-off-by: David Gibson <[email protected]>
eaton-coreymutter · Nov 24, 2020 · 5e73586 · 5e73586
1 parent 67849a3
commit 5e73586
Show file tree

Hide file tree

Showing 2 changed files with 9 additions and 1 deletion.
diff --git a/libfdt/fdt.c b/libfdt/fdt.c
@@ -22,6 +22,10 @@ int32_t fdt_ro_probe_(const void *fdt)
 	if (can_assume(VALID_DTB))
 		return totalsize;
 
+	/* The device tree must be at an 8-byte aligned address */
+	if ((uintptr_t)fdt & 7)
+		return -FDT_ERR_ALIGNMENT;
+
 	if (fdt_magic(fdt) == FDT_MAGIC) {
 		/* Complete tree */
 		if (!can_assume(LATEST)) {

diff --git a/libfdt/libfdt.h b/libfdt/libfdt.h
@@ -101,7 +101,11 @@ extern "C" {
 	/* FDT_ERR_BADFLAGS: The function was passed a flags field that
 	 * contains invalid flags or an invalid combination of flags. */
 
-#define FDT_ERR_MAX		18
+#define FDT_ERR_ALIGNMENT	19
+	/* FDT_ERR_ALIGNMENT: The device tree base address is not 8-byte
+	 * aligned. */
+
+#define FDT_ERR_MAX		19
 
 /* constants */
 #define FDT_MAX_PHANDLE 0xfffffffe