wip crash commands

Author: osandov

drgn/commands/_builtin/crash/mm.py

@@ -0,0 +1,148 @@
+# Copyright (c) Meta Platforms, Inc. and affiliates.
+# SPDX-License-Identifier: LGPL-2.1-or-later
+
+import argparse
+from typing import Any
+
+from drgn import Program
+from drgn.commands import argument, drgn_argument
+from drgn.commands.crash import crash_command
+from drgn.helpers.common.format import print_table
+from drgn.helpers.linux.mm import follow_phys, page_to_phys, phys_to_page
+
+
+@crash_command(
+    description="bytes to page",
+    long_description="Convert byte numbers (usually physical addresses) to page numbers.",
+    arguments=(
+        argument(
+            "address",
+            type="hexadecimal",
+            nargs="+",
+            help="hexadecimal byte number/physical address",
+        ),
+        drgn_argument,
+    ),
+)
+def _crash_cmd_btop(
+    prog: Program, name: str, args: argparse.Namespace, **kwargs: Any
+) -> None:
+    if args.drgn:
+        print(
+            """\
+PHYS_PFN(address)
+# or
+address >> prog["PAGE_SHIFT"]"""
+        )
+        return
+
+    PAGE_SHIFT = prog["PAGE_SHIFT"].value_()
+    for address in args.address:
+        print(f"{address:x}: {address >> PAGE_SHIFT:x}")
+
+
+@crash_command(
+    description="page to bytes",
+    long_description="Convert page frame numbers to byte numbers (physical addresses).",
+    arguments=(
+        argument(
+            "pfn", type="decimal_or_hexadecimal", nargs="+", help="page frame number"
+        ),
+        drgn_argument,
+    ),
+)
+def _crash_cmd_ptob(
+    prog: Program, name: str, args: argparse.Namespace, **kwargs: Any
+) -> None:
+    if args.drgn:
+        print(
+            """\
+PFN_PHYS(address)
+# or
+address << prog["PAGE_SHIFT"]"""
+        )
+        return
+
+    PAGE_SHIFT = prog["PAGE_SHIFT"].value_()
+    for pfn in args.pfn:
+        print(f"{pfn:x}: {pfn << PAGE_SHIFT:x}")
+
+
+@crash_command(
+    description="physical or per-CPU to virtual",
+    long_description="TODO",
+    arguments=(
+        argument(
+            "address",
+            metavar="address|offset:cpuspec",
+            type="hexadecimal",
+            nargs="+",
+            help="hexadecimal physical address or hexadecimal per-CPU offset and CPU specifier",
+        ),
+        drgn_argument,
+    ),
+)
+def _crash_cmd_ptov(
+    prog: Program, name: str, args: argparse.Namespace, **kwargs: Any
+) -> None:
+    if args.drgn:
+        print("phys_to_virt(address)")
+        return
+
+    # TODO
+
+
+@crash_command(
+    description="virtual to physical",
+    long_description="TODO",
+    arguments=(
+        # TODO: -c flag
+        # argument(
+        #     "-c", dest="task", metavar="pid | taskp", help="TODO"
+        # ),
+        # TODO: -k, -u flags
+        argument(
+            "address", type="hexadecimal", nargs="+", help="hexadecimal virtual address"
+        ),
+        drgn_argument,
+    ),
+)
+def _crash_cmd_vtop(
+    prog: Program, name: str, args: argparse.Namespace, **kwargs: Any
+) -> None:
+    # TODO: --drgn
+
+    mm = prog["init_mm"].address_of_()
+
+    for i, address in enumerate(args.address):
+        phys = follow_phys(mm, address)
+        page = phys_to_page(phys)
+
+        if i != 0:
+            print()
+        print_table(
+            (
+                ("VIRTUAL", "PHYSICAL"),
+                (f"{address:x}", f"{phys.value_():x}"),
+            )
+        )
+
+        # TODO: page table info
+
+        # TODO: crash tries printing VMAs, possibly other things?
+
+        print()
+        # TODO: we justify things differently than crash
+        print_table(
+            (
+                ("PAGE", "PHYSICAL", "MAPPING", "INDEX", "CNT", "FLAGS"),
+                (
+                    f"{page.value_():x}",
+                    f"{page_to_phys(page).value_():x}",
+                    f"{page.mapping.value_():x}",
+                    "TODO",  # TODO: not sure what base these are in
+                    "TODO",
+                    f"{page.flags.value_():x}",
+                ),
+            )
+        )