Considering this case:
1. A program opens a sysfs table file 65535 times, it can increase
validation_count and first increment cause the table to be mapped:
validation_count = 65535
2. AML execution causes "Load" to be executed on the same
table, this time it cannot increase validation_count, so
validation_count remains:
validation_count = 65535
3. The program closes sysfs table file 65535 times, it can decrease
validation_count and the last decrement cause the table to be
unmapped:
validation_count = 0
4. AML code still accessing the loaded table, kernel crash can be
observed.
To prevent that from happening, add a validation_count threashold.
When it is reached, the validation_count can no longer be
incremented/decremented to invalidate the table descriptor (means
preventing table unmappings)
Note that code added in acpi_tb_put_table() is actually a no-op but
changes the warning message into a "warn once" one. Lv Zheng.
Signed-off-by: Lv Zheng <lv.zheng@intel.com>
[ rjw: Changelog, comments ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
ACPICA commit cac6790954d4d752a083e6122220b8a22febcd07
This patch back ports Linux acpi_get_table_with_size() and
early_acpi_os_unmap_memory() into ACPICA upstream to reduce divergences.
The 2 APIs are used by Linux as table management APIs for long time, it
contains a hidden logic that during the early stage, the mapped tables
should be unmapped before the early stage ends.
During the early stage, tables are handled by the following sequence:
acpi_get_table_with_size();
parse the table
early_acpi_os_unmap_memory();
During the late stage, tables are handled by the following sequence:
acpi_get_table();
parse the table
Linux uses acpi_gbl_permanent_mmap to distinguish the early stage and the
late stage.
The reasoning of introducing acpi_get_table_with_size() is: ACPICA will
remember the early mapped pointer in acpi_get_table() and Linux isn't able to
prevent ACPICA from using the wrong early mapped pointer during the late
stage as there is no API provided from ACPICA to be an inverse of
acpi_get_table() to forget the early mapped pointer.
But how ACPICA can work with the early/late stage requirement? Inside of
ACPICA, tables are ensured to be remained in "INSTALLED" state during the
early stage, and they are carefully not transitioned to "VALIDATED" state
until the late stage. So the same logic is in fact implemented inside of
ACPICA in a different way. The gap is only that the feature is not provided
to the OSPMs in an accessible external API style.
It then is possible to fix the gap by providing an inverse of
acpi_get_table() from ACPICA, so that the two Linux sequences can be
combined:
acpi_get_table();
parse the table
acpi_put_table();
In order to work easier with the current Linux code, acpi_get_table() and
acpi_put_table() is implemented in a usage counting based style:
1. When the usage count of the table is increased from 0 to 1, table is
mapped and .Pointer is set with the mapping address (VALIDATED);
2. When the usage count of the table is decreased from 1 to 0, .Pointer
is unset and the mapping address is unmapped (INVALIDATED).
So that we can deploy the new APIs to Linux with minimal effort by just
invoking acpi_get_table() in acpi_get_table_with_size() and invoking
acpi_put_table() in early_acpi_os_unmap_memory(). Lv Zheng.
Link: https://github.com/acpica/acpica/commit/cac67909
Signed-off-by: Lv Zheng <lv.zheng@intel.com>
Signed-off-by: Bob Moore <robert.moore@intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
ACPICA commit 34ccd43af3fd1870fddfac0617dd0ba706963558
Remove all vestiges of the version 2 FADT which never was included
in the ACPI specification.
This enabled significant cleanup of both the data table compiler
and the disassembler.
Added many clarification comments to associate each FADT version
with the version of the ACPI spec where it was originally
defined.
Link: https://github.com/acpica/acpica/commit/34ccd43a
Signed-off-by: Bob Moore <robert.moore@intel.com>
Signed-off-by: Lv Zheng <lv.zheng@intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
This patch refines ACPI_TABLE_ORIGIN_xxx flags. No functional changes.
The previous commits have introduced the following internal APIs:
1. acpi_tb_acquire_table: Acquire struct acpi_table_header according to
ACPI_TABLE_ORIGIN_xxx flags.
2. acpi_tb_release_table: Release struct acpi_table_header according to
ACPI_TABLE_ORIGIN_xxx flags.
3. acpi_tb_install_table: Make struct acpi_table_desc.Address not NULL according to
ACPI_TABLE_ORIGIN_xxx flags.
4. acpi_tb_uninstall_table: Make struct acpi_table_desc.Address NULL according to
ACPI_TABLE_ORIGIN_xxx flags.
5. acpi_tb_validate_table: Make struct acpi_table_desc.Pointer not NULL according to
ACPI_TABLE_ORIGIN_xxx flags.
6. acpi_tb_invalidate_table: Make struct acpi_table_desc.Pointer NULL according to
ACPI_TABLE_ORIGIN_xxx flags.
It thus detects that the ACPI_TABLE_ORIGIN_UNKNOWN is redundant to
ACPI_TABLE_ORIGIN_OVERRIDE.
The ACPI_TABLE_ORIGIN_xxTERN_VIRTUAL flags are named as VIRTUAL in order
not to confuse with x86 logical address, this patch also renames all
"logical override" into "virtual override".
Signed-off-by: Lv Zheng <lv.zheng@intel.com>
Signed-off-by: Bob Moore <robert.moore@intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
This reverts commit aae576e5faefa8ba70647efa320d4747b6375f1e.
Push and Pop are not portable "enough", and caused problems for
some ACPICA customers.
Signed-off-by: Robert Moore <Robert.Moore@intel.com>
Signed-off-by: Lv Zheng <lv.zheng@intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Use push and pop to both guarantee that the correct alignment is used,
and to restore the alignment to whatever it was before the header
was included.
It is reported that the #pragma pack(push/pop) directives are not supported
by the specific GCCs, but this patch still doesn't affect kernel build
as there are already #pragma pack([1]) directives used in the old ACPICA
headers, which means there shouldn't be GCCs that are currently used to
compile the ACPI kernels do not support #pragma pack() directives.
References: https://bugs.acpica.org/show_bug.cgi?id=1058
Signed-off-by: Bob Moore <robert.moore@intel.com>
Signed-off-by: Lv Zheng <lv.zheng@intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Some platforms contain an XSDT that is ill-formed or otherwise invalid
(such as containing some or all entries that are NULL pointers).
This change adds a new function to validate the XSDT before actually
using it. If the XSDT is found to be invalid, ACPICA will now fall
back to using the RSDT instead.
This feature is already in the Linux kernel. When it is back ported to
ACPICA, code is refined to follow ACPICA coding style and this patch
is the generation of the integration.
Original-by: Zhao Yakui <yakui.zhao@intel.com>
Signed-off-by: Lv Zheng <lv.zheng@intel.com>
Signed-off-by: Bob Moore <robert.moore@intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
This patch updates RSDP table header definitions as such enhancement
has been made in ACPICA upstream already. It ports that change to
the Linux source to reduce source code differences between Linux and
ACPICA upstream.
This patch does not affect the generation of the Linux kernel binary.
[rjw: Changelog]
Signed-off-by: Lv Zheng <lv.zheng@intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
