scripts/gdb: add mm introspection utils

scripts/gdb: add mm introspection utils

This command provides a way to traverse the entire page hierarchy by a
given virtual address on x86.  In addition to qemu's commands info
tlb/info mem it provides the complete information about the paging
structure for an arbitrary virtual address.  It supports 4KB/2MB/1GB and 5
level paging.

Here is an example output for 2MB success translation:

(gdb) translate-vm address
cr3:
    cr3 binary data                0x1085be003
    next entry physical address   0x1085be000
    ---
    bit  3          page level write through       False
    bit  4          page level cache disabled      False
level 4:
    entry address                  0xffff8881085be7f8
    page entry binary data         0x800000010ac83067
    next entry physical address   0x10ac83000
    ---
    bit  0          entry present                  True
    bit  1          read/write access allowed      True
    bit  2          user access allowed            True
    bit  3          page level write through       False
    bit  4          page level cache disabled      False
    bit  5          entry has been accessed        True
    bit  7          page size                      False
    bit  11         restart to ordinary            False
    bit  63         execute disable                True
level 3:
    entry address                  0xffff88810ac83a48
    page entry binary data         0x101af7067
    next entry physical address   0x101af7000
    ---
    bit  0          entry present                  True
    bit  1          read/write access allowed      True
    bit  2          user access allowed            True
    bit  3          page level write through       False
    bit  4          page level cache disabled      False
    bit  5          entry has been accessed        True
    bit  7          page size                      False
    bit  11         restart to ordinary            False
    bit  63         execute disable                False
level 2:
    entry address                  0xffff888101af7368
    page entry binary data         0x80000001634008e7
    page size                      2MB
    page physical address         0x163400000
    ---
    bit  0          entry present                  True
    bit  1          read/write access allowed      True
    bit  2          user access allowed            True
    bit  3          page level write through       False
    bit  4          page level cache disabled      False
    bit  5          entry has been accessed        True
    bit  7          page size                      True
    bit  6          page dirty                     True
    bit  8          global translation             False
    bit  11         restart to ordinary            True
    bit  12         pat                            False
    bits (59, 62)   protection key                 0
    bit  63         execute disable                True

[dmitrii.bundin.a@gmail.com: add SPDX line, other tweaks]
Link: https://lkml.kernel.org/r/20230113175151.22278-1-dmitrii.bundin.a@gmail.com
[akpm@linux-foundation.org: s/physicall/physical/]
Link: https://lkml.kernel.org/r/20230102171014.31408-1-dmitrii.bundin.a@gmail.com
Signed-off-by: Dmitrii Bundin <dmitrii.bundin.a@gmail.com>
Acked by: Mike Rapoport (IBM) <rppt@kernel.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jan Kiszka <jan.kiszka@siemens.com>
Cc: Kieran Bingham <kbingham@kernel.org>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>