arch.py: fix arch detection for riscv (#1962)

* arch.py: fix arch detection for riscv again

* arch.py: fix arch detection for riscv again

* arch.py: fix lint

pwndbg/gdblib/arch.py

@@ -9,7 +9,20 @@ from pwndbg.lib.arch import Arch
 
 # TODO: x86-64 needs to come before i386 in the current implementation, make
 # this order-independent
-ARCHS = ("x86-64", "i386", "aarch64", "mips", "powerpc", "sparc", "arm", "armcm", "rv32", "rv64")
+ARCHS = (
+    "x86-64",
+    "i386",
+    "aarch64",
+    "mips",
+    "powerpc",
+    "sparc",
+    "arm",
+    "armcm",
+    "riscv:rv32",
+    "riscv:rv64",
+    "riscv",
+)
+
 
 # mapping between gdb and pwntools arch names
 pwnlib_archs_mapping = {
@@ -49,6 +62,10 @@ def _get_arch(ptrsize: int):
             # Distinguish between Cortex-M and other ARM
             if match == "arm" and "-m" in arch:
                 match = "armcm"
+            elif match.startswith("riscv:"):
+                match = match[6:]
+            elif match == "riscv":
+                match = "rv64"
             return match, ptrsize, endian
 
     if not_exactly_arch: