Allow running cpsr command on aarch64 (#1437)

Co-authored-by: Gulshan Singh <gsgx@google.com>

pwndbg/commands/cpsr.py

@@ -2,31 +2,13 @@ import pwndbg.commands
 import pwndbg.gdblib.arch
 import pwndbg.gdblib.regs
 from pwndbg.color import context
-from pwndbg.color import message
 
 
-@pwndbg.commands.ArgparsedCommand("Print out ARM CPSR or xPSR register")
+@pwndbg.commands.ArgparsedCommand("Print out ARM CPSR or xPSR register", aliases=["xpsr", "pstate"])
+@pwndbg.commands.OnlyWithArch(["arm", "armcm", "aarch64"])
 @pwndbg.commands.OnlyWhenRunning
 def cpsr():
-    arm_print_psr()
-
-
-@pwndbg.commands.ArgparsedCommand("Print out ARM xPSR or CPSR register")
-@pwndbg.commands.OnlyWhenRunning
-def xpsr():
-    arm_print_psr()
-
-
-def arm_print_psr():
-    if pwndbg.gdblib.arch.current not in ("arm", "armcm"):
-        print(message.warn("This is only available on ARM"))
-        return
-
-    reg = "cpsr" if pwndbg.gdblib.arch.current == "arm" else "xpsr"
-    print(
-        "%s %s"
-        % (
-            reg,
-            context.format_flags(getattr(pwndbg.gdblib.regs, reg), pwndbg.gdblib.regs.flags[reg]),
-        )
-    )
+    reg = "xpsr" if pwndbg.gdblib.arch.name == "armcm" else "cpsr"
+    reg_val = getattr(pwndbg.gdblib.regs, reg)
+    reg_flags = pwndbg.gdblib.regs.flags[reg]
+    print(f"{reg} {context.format_flags(reg_val, reg_flags)}")

pwndbg/lib/regs.py

@@ -94,6 +94,25 @@ arm_xpsr_flags = collections.OrderedDict(
     [("N", 31), ("Z", 30), ("C", 29), ("V", 28), ("Q", 27), ("T", 24)]
 )
 
+aarch64_cpsr_flags = collections.OrderedDict(
+    [
+        ("N", 31),
+        ("Z", 30),
+        ("C", 29),
+        ("V", 28),
+        ("Q", 27),
+        ("PAN", 22),
+        ("IL", 20),
+        ("D", 9),
+        ("A", 8),
+        ("I", 7),
+        ("F", 6),
+        # TODO: EL is two bits
+        ("EL", 2),
+        ("SP", 0),
+    ]
+)
+
 arm = RegisterSet(
     retaddr=("lr",),
     flags={"cpsr": arm_cpsr_flags},
@@ -111,10 +130,10 @@ armcm = RegisterSet(
     retval="r0",
 )
 
-# FIXME AArch64 does not have a CPSR register
+# AArch64 has a PSTATE register, but GDB represents it as the CPSR register
 aarch64 = RegisterSet(
     retaddr=("lr",),
-    flags={"cpsr": {}},
+    flags={"cpsr": aarch64_cpsr_flags},
     # X29 is the frame pointer register (FP) but setting it
     # as frame here messes up the register order to the point
     # it's confusing. Think about improving this if frame