michaelh/zephyr
1
0
Fork 0
Code Releases Activity

x86: mmu: allow page table extra mappings to have cache disabled

Browse source 
This adds the bits to the gen_mmu.py script so that extra mappings
can be added with caching disabled. This is useful for mapping
MMIO regions where caching is not desired.

Signed-off-by: Daniel Leung <daniel.leung@intel.com>
This commit is contained in:
Daniel Leung 2021-04-27 10:27:47 -07:00 • committed by Anas Nashif
commit 54283efcce
2 changed files with 17 additions and 8 deletions
Download patch file Download diff file Expand all files Collapse all files

23
arch/x86/gen_mmu.py
View file

@ -93,6 +93,7 @@ def bit(pos):
FLAG_P = bit(0) FLAG_P = bit(0)
FLAG_RW = bit(1) FLAG_RW = bit(1)
FLAG_US = bit(2) FLAG_US = bit(2)
FLAG_CD = bit(4)
FLAG_SZ = bit(7) FLAG_SZ = bit(7)
FLAG_G = bit(8) FLAG_G = bit(8)
FLAG_XD = bit(63) FLAG_XD = bit(63)
@ -159,6 +160,9 @@ def dump_flags(flags):
if flags & FLAG_SZ: if flags & FLAG_SZ:
ret += "SZ " ret += "SZ "
if flags & FLAG_CD:
ret += "CD "
return ret.strip() return ret.strip()
@ -289,7 +293,7 @@ class Pdpt(MMUTable):
addr_mask = 0x7FFFFFFFFFFFF000 addr_mask = 0x7FFFFFFFFFFFF000
type_code = 'Q' type_code = 'Q'
num_entries = 512 num_entries = 512
supported_flags = INT_FLAGS | FLAG_SZ supported_flags = INT_FLAGS | FLAG_SZ | FLAG_CD
class PdptPAE(Pdpt): class PdptPAE(Pdpt):
"""Page directory pointer table for PAE""" """Page directory pointer table for PAE"""
@ -301,7 +305,7 @@ class Pd(MMUTable):
addr_mask = 0xFFFFF000 addr_mask = 0xFFFFF000
type_code = 'I' type_code = 'I'
num_entries = 1024 num_entries = 1024
supported_flags = INT_FLAGS | FLAG_SZ supported_flags = INT_FLAGS | FLAG_SZ | FLAG_CD
class PdXd(Pd): class PdXd(Pd):
"""Page directory for either PAE or IA-32e""" """Page directory for either PAE or IA-32e"""
@ -316,7 +320,7 @@ class Pt(MMUTable):
addr_mask = 0xFFFFF000 addr_mask = 0xFFFFF000
type_code = 'I' type_code = 'I'
num_entries = 1024 num_entries = 1024
supported_flags = (FLAG_P | FLAG_RW | FLAG_US | FLAG_G | supported_flags = (FLAG_P | FLAG_RW | FLAG_US | FLAG_G | FLAG_CD |
FLAG_IGNORED0 | FLAG_IGNORED1) FLAG_IGNORED0 | FLAG_IGNORED1)
class PtXd(Pt): class PtXd(Pt):
@ -324,7 +328,7 @@ class PtXd(Pt):
addr_mask = 0x07FFFFFFFFFFF000 addr_mask = 0x07FFFFFFFFFFF000
type_code = 'Q' type_code = 'Q'
num_entries = 512 num_entries = 512
supported_flags = (FLAG_P | FLAG_RW | FLAG_US | FLAG_G | FLAG_XD | supported_flags = (FLAG_P | FLAG_RW | FLAG_US | FLAG_G | FLAG_XD | FLAG_CD |
FLAG_IGNORED0 | FLAG_IGNORED1 | FLAG_IGNORED2) FLAG_IGNORED0 | FLAG_IGNORED1 | FLAG_IGNORED2)
@ -610,12 +614,13 @@ def parse_args():
parser.add_argument("--map", action='append', parser.add_argument("--map", action='append',
help=textwrap.dedent('''\ help=textwrap.dedent('''\
Map extra memory: Map extra memory:
<physical address>,<size>[,<flags:LUWX>[,<virtual adderss>]] <physical address>,<size>[,<flags:LUWXD>[,<virtual adderss>]]
where flags can be empty or combination of: where flags can be empty or combination of:
L - Large page (2MB or 4MB), L - Large page (2MB or 4MB),
U - Userspace accessible, U - Userspace accessible,
W - Writable, W - Writable,
X - Executable. X - Executable,
D - Cache disabled.
Default is Default is
small (4KB) page, small (4KB) page,
supervisor only, supervisor only,
@ -625,7 +630,7 @@ def parse_args():
parser.add_argument("-v", "--verbose", action="count", parser.add_argument("-v", "--verbose", action="count",
help="Print extra debugging information") help="Print extra debugging information")
args = parser.parse_args() args = parser.parse_args()
if "VERBOSE" in os.environ and args.verbose == 0: if "VERBOSE" in os.environ:
args.verbose = 1 args.verbose = 1
@ -677,7 +682,7 @@ def map_extra_regions(pt):
map_flags = elements[2] map_flags = elements[2]
# Check for allowed flags # Check for allowed flags
if not bool(re.match('^[LUWX]*$', map_flags)): if not bool(re.match('^[LUWXD]*$', map_flags)):
error("Unrecognized flags: %s" % map_flags) error("Unrecognized flags: %s" % map_flags)
flags = FLAG_P | ENTRY_XD flags = FLAG_P | ENTRY_XD
@ -690,6 +695,8 @@ def map_extra_regions(pt):
if 'L' in map_flags: if 'L' in map_flags:
flags |= FLAG_SZ flags |= FLAG_SZ
one_map['large_page'] = True one_map['large_page'] = True
if 'D' in map_flags:
flags |= FLAG_CD
one_map['flags'] = flags one_map['flags'] = flags

2
doc/guides/arch/x86.rst
View file

@ -112,6 +112,8 @@ The argument ``--map`` takes the following value:
- ``X``: Allow execution. - ``X``: Allow execution.
- ``D``: Cache disabled.
- Default is small page (4KB), supervisor only, read only, and - Default is small page (4KB), supervisor only, read only, and
execution disabled. execution disabled.