scripts/gdb: add read_u16/32/64 helpers

Add helpers for reading integers from target memory buffers.  Required
when caching the memory access is more efficient than reading individual
values via gdb.

Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Jason Wessel <jason.wessel@windriver.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Ben Widawsky <ben@bwidawsk.net>
Cc: Borislav Petkov <bp@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

scripts/gdb/linux/utils.py

@@ -85,3 +85,24 @@ def get_target_endianness():
         else:
             raise gdb.GdgError("unknown endianness '{0}'".format(endian))
     return target_endianness
+
+
+def read_u16(buffer):
+    if get_target_endianness() == LITTLE_ENDIAN:
+        return ord(buffer[0]) + (ord(buffer[1]) << 8)
+    else:
+        return ord(buffer[1]) + (ord(buffer[0]) << 8)
+
+
+def read_u32(buffer):
+    if get_target_endianness() == LITTLE_ENDIAN:
+        return read_u16(buffer[0:2]) + (read_u16(buffer[2:4]) << 16)
+    else:
+        return read_u16(buffer[2:4]) + (read_u16(buffer[0:2]) << 16)
+
+
+def read_u64(buffer):
+    if get_target_endianness() == LITTLE_ENDIAN:
+        return read_u32(buffer[0:4]) + (read_u32(buffer[4:8]) << 32)
+    else:
+        return read_u32(buffer[4:8]) + (read_u32(buffer[0:4]) << 32)