ACPICA: Add acpi_update_interfaces public interface

Add new API to allow OSPM to disable/enable specific types of _OSI interface strings.

ACPICA does not have the knowledge about whether an _OSI interface string is an OS vendor string or a feature group string and there isn't any API interface to allow OSPM to install a new interface string as a feature group string.
This patch simply adds all feature group strings defined by ACPI specification into the acpi_default_supported_interfaces with ACPI_OSI_FEATURE flag set to fix this gap. This patch also adds codes to keep their default states as ACPI_OSI_INVALID before the initialization and after the termination.

Reported by Lv Zheng.

---
 drivers/acpi/acpica/aclocal.h |    3 ++
 drivers/acpi/acpica/acutils.h |    2 ++
 drivers/acpi/acpica/utosi.c   |   77 ++++++++++++++++++++++++++++++++++-------
 drivers/acpi/acpica/utxface.c |   29 ++++++++++++++++
 include/acpi/acpixf.h         |    2 ++
 include/acpi/actypes.h        |   14 ++++++++
 6 files changed, 114 insertions(+), 13 deletions(-)

index dfed265..42f1be3 100644
@@ -955,6 +955,9 @@ struct acpi_interface_info {
 
 #define ACPI_OSI_INVALID                0x01
 #define ACPI_OSI_DYNAMIC                0x02
+#define ACPI_OSI_FEATURE                0x04
+#define ACPI_OSI_DEFAULT_INVALID        0x08
+#define ACPI_OSI_OPTIONAL_FEATURE       (ACPI_OSI_FEATURE | ACPI_OSI_DEFAULT_INVALID | ACPI_OSI_INVALID)
 
 struct acpi_port_info {
 	char *name;

index 3c76ede..f7b3f68 100644
@@ -470,6 +470,8 @@ acpi_status acpi_ut_install_interface(acpi_string interface_name);
 
 acpi_status acpi_ut_remove_interface(acpi_string interface_name);
 
+acpi_status acpi_ut_update_interfaces(u8 action);
+
 struct acpi_interface_info *acpi_ut_get_interface(acpi_string interface_name);
 
 acpi_status acpi_ut_osi_implementation(struct acpi_walk_state *walk_state);

index 6505774..03a211e 100644
@@ -389,6 +389,34 @@ ACPI_EXPORT_SYMBOL(acpi_install_interface_handler)
 
 /*****************************************************************************
  *
+ * FUNCTION:    acpi_update_interfaces
+ *
+ * PARAMETERS:  action              - Actions to be performed during the
+ *                                    update
+ *
+ * RETURN:      Status
+ *
+ * DESCRIPTION: Update _OSI interface strings, disabling or enabling OS vendor
+ *              string or/and feature group strings.
+ *
+ ****************************************************************************/
+acpi_status acpi_update_interfaces(u8 action)
+{
+	acpi_status status;
+
+	status = acpi_os_acquire_mutex(acpi_gbl_osi_mutex, ACPI_WAIT_FOREVER);
+	if (ACPI_FAILURE(status)) {
+		return (status);
+	}
+
+	status = acpi_ut_update_interfaces(action);
+
+	acpi_os_release_mutex(acpi_gbl_osi_mutex);
+	return (status);
+}
+
+/*****************************************************************************
+ *
  * FUNCTION:    acpi_check_address_range
  *
  * PARAMETERS:  space_id            - Address space ID

@@ -402,6 +430,7 @@ ACPI_EXPORT_SYMBOL(acpi_install_interface_handler)
  *              ASL operation region address ranges.
  *
  ****************************************************************************/
+
 u32
 acpi_check_address_range(acpi_adr_space_type space_id,
 			 acpi_physical_address address,

index 1b09300..c2705e8 100644
@@ -146,6 +146,8 @@ acpi_status acpi_install_interface(acpi_string interface_name);
 
 acpi_status acpi_remove_interface(acpi_string interface_name);
 
+acpi_status acpi_update_interfaces(u8 action);
+
 u32
 acpi_check_address_range(acpi_adr_space_type space_id,
 			 acpi_physical_address address,

index a64adcc..549bdfb 100644
@@ -1144,4 +1144,18 @@ struct acpi_memory_list {
 #endif
 };
 
+/* _OSI update actions */
+
+#define ACPI_VENDOR_STRINGS                 0x01
+#define ACPI_FEATURE_STRINGS                0x02
+#define ACPI_ENABLE_INTERFACES              0x00
+#define ACPI_DISABLE_INTERFACES             0x04
+
+#define ACPI_DISABLE_ALL_VENDOR_STRINGS     (ACPI_DISABLE_INTERFACES | ACPI_VENDOR_STRINGS)
+#define ACPI_DISABLE_ALL_FEATURE_STRINGS    (ACPI_DISABLE_INTERFACES | ACPI_FEATURE_STRINGS)
+#define ACPI_DISABLE_ALL_STRINGS            (ACPI_DISABLE_INTERFACES | ACPI_VENDOR_STRINGS | ACPI_FEATURE_STRINGS)
+#define ACPI_ENABLE_ALL_VENDOR_STRINGS      (ACPI_ENABLE_INTERFACES | ACPI_VENDOR_STRINGS)
+#define ACPI_ENABLE_ALL_FEATURE_STRINGS     (ACPI_ENABLE_INTERFACES | ACPI_FEATURE_STRINGS)
+#define ACPI_ENABLE_ALL_STRINGS             (ACPI_ENABLE_INTERFACES | ACPI_VENDOR_STRINGS | ACPI_FEATURE_STRINGS)
+
 #endif				/* __ACTYPES_H__ */

1.7.10

This patch introduces "acpi_osi=!" command line to force Linux replying "UNSUPPORTED" to all of the _OSI strings. This patch is based on an ACPICA enhancement - the new API acpi_update_interfaces().

The _OSI object provides the platform with the ability to query OSPM to determine the set of ACPI related interfaces, behaviors, or features that the operating system supports. The argument passed to the _OSI is a string like the followings:
1. Feature Group String, examples include
Module Device
Processor Device
3.0 _SCP Extensions
Processor Aggregator Device
...
2. OS Vendor String, examples include
Linux
FreeBSD
Windows
...

There are AML codes provided in the ACPI namespace written in the following style to determine OSPM interfaces / features:

    Method(OSCK)
    {
        if (CondRefOf(_OSI, Local0))
        {
            if (\_OSI("Windows"))
            {
                Return (One)
            }
            if (\_OSI("Windows 2006"))
            {
                Return (Ones)
            }
            Return (Zero)
        }
        Return (Zero)
    }

There is a debugging facility implemented in the Linux. Users can pass "acpi_osi=" boot parameters to the kernel to tune the _OSI evaluation result so that certain AML codes can be executed. Current implementation includes:
1. 'acpi_osi=' - this makes CondRefOf(_OSI, Local0) TRUE
2. 'acpi_osi="Windows"' - this makes \_OSI("Windows") TRUE
3. 'acpi_osi="!Windows"' - this makes \_OSI("Windows") FALSE The function to implement this feature is also used as a quirk mechanism in the Linux ACPI subystem.

When _OSI is evaluatated by the AML codes, ACPICA replies "SUPPORTED" to all Windows operating system vendor strings. This is because Windows operating systems return "SUPPORTED" if the argument to the _OSI method specifies an earlier version of Windows. Please refer to the following MSDN document:
How to Identify the Windows Version in ACPI by Using _OSI
http://msdn.microsoft.com/en-us/library/hardware/gg463275.aspx

This adds difficulties when developers want to feed specific Windows operating system vendor string to the BIOS codes for debugging purpose, multiple acpi_osi="!xxx" should be specified in the command line to force Linux replying "UNSUPPORTED" to the Windows OS vendor strings listed in the AML codes.

This patch has passed a unit test carried out by AcpiExec.

---
 Documentation/kernel-parameters.txt |   29 +++++++++++++++++++++++++++--
 drivers/acpi/osl.c                  |   14 +++++++++++++-
 2 files changed, 40 insertions(+), 3 deletions(-)

index 7f64e0f..131394f 100644
@@ -235,10 +235,35 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
 			Format: To spoof as Windows 98: ="Microsoft Windows"
 
 	acpi_osi=	[HW,ACPI] Modify list of supported OS interface strings
-			acpi_osi="string1"	# add string1 -- only one string
-			acpi_osi="!string2"	# remove built-in string2
+			acpi_osi="string1"	# add string1
+			acpi_osi="!string2"	# remove string2
+			acpi_osi=!		# disable all built-in OS vendor
+						  strings
 			acpi_osi=		# disable all strings
 
+			'acpi_osi=!' can be used in combination with single or
+			multiple 'acpi_osi="string1"' to support specific OS
+			vendor string(s).  Note that such command can only
+			affect the default state of the OS vendor strings, thus
+			it cannot affect the default state of the feature group
+			strings and the current state of the OS vendor strings,
+			specifying it multiple times through kernel command line
+			is meaningless.
+			Examples:
+			  1. 'acpi_osi=! acpi_osi="Windows 2000"' is equivalent
+			     to 'acpi_osi="Windows 2000" acpi_osi=!', they all
+			     can make '_OSI("Windows 2000")' TRUE.
+
+			'acpi_osi=' cannot be used in combination with other
+			'acpi_osi=' command lines, the _OSI method will not
+			exist in the ACPI namespace.  NOTE that such command can
+			only affect the _OSI support state, thus specifying it
+			multiple times through kernel command line is also
+			meaningless.
+			Examples:
+			  1. 'acpi_osi=' can make 'CondRefOf(_OSI, Local1)'
+			     FALSE.
+
 	acpi_pm_good	[X86]
 			Override the pmtimer bug detection: force the kernel
 			to assume that this machine's pmtimer latches its value

index da6b663..5dc311d 100644
@@ -140,7 +140,8 @@ static struct osi_linux {
 	unsigned int	enable:1;
 	unsigned int	dmi:1;
 	unsigned int	cmdline:1;
-} osi_linux = {0, 0, 0};
+	unsigned int	default_disabling:1;
+} osi_linux = {0, 0, 0, 0};
 
 static u32 acpi_osi_handler(acpi_string interface, u32 supported)
 {

@@ -1386,6 +1387,10 @@ void __init acpi_osi_setup(char *str)
 
 	if (*str == '!') {
 		str++;
+		if (*str == '\0') {
+			osi_linux.default_disabling = 1;
+			return;
+		}
 		enable = false;
 	}
 

@@ -1451,6 +1456,13 @@ static void __init acpi_osi_setup_late(void)
 	int i;
 	acpi_status status;
 
+	if (osi_linux.default_disabling) {
+		status = acpi_update_interfaces(ACPI_DISABLE_ALL_VENDOR_STRINGS);
+
+		if (ACPI_SUCCESS(status))
+			printk(KERN_INFO PREFIX "Disabled all _OSI OS vendors\n");
+	}
+
 	for (i = 0; i < OSI_STRING_ENTRIES_MAX; i++) {
 		osi = &osi_setup_entries[i];
 		str = osi->string;

1.7.10

This patchset includes 1 ACPICA patches and 2 Linux patches to facilitate Linux with the ability to disable _OSI vendor strings and _OSI feature group strings.
This patchset has passed a unit test carried out by the codes ported from Linux to ACPICA.

Lv Zheng (3):
ACPICA: Add acpi_update_interfaces public interface
ACPI: Add facility to disable all _OSI OS vendor strings
ACPI: Add facility to remove all _OSI strings

 Documentation/kernel-parameters.txt |   55 ++++++++++++++++++++++++-
 drivers/acpi/acpica/aclocal.h       |    3 ++
 drivers/acpi/acpica/acutils.h       |    2 +
 drivers/acpi/acpica/utosi.c         |   77 +++++++++++++++++++++++++++++------
 drivers/acpi/acpica/utxface.c       |   29 +++++++++++++
 drivers/acpi/osl.c                  |   21 +++++++++-
 include/acpi/acpixf.h               |    2 +
 include/acpi/actypes.h              |   14 +++++++
 8 files changed, 187 insertions(+), 16 deletions(-)

1.7.10

This patch changes the "acpi_osi=" boot parameter implementation so that:
1. "acpi_osi=!" can be used to disable all _OSI OS vendor strings by default. It is meaningless to specify "acpi_osi=!" multiple times as it can only affect the default state of the target _OSI strings.
2. "acpi_osi=!*" can be used to more all _OSI OS vendor strings and all _OSI feature group strings. It is useful to specify "acpi_osi=!*" multiple times through kernel command line to override the current state of the target _OSI strings.

This patch has passed the test brought by an ACPICA commit for the unit test purpose.

---
 Documentation/kernel-parameters.txt |   28 +++++++++++++++++++++++++++-
 drivers/acpi/osl.c                  |    7 +++++++
 2 files changed, 34 insertions(+), 1 deletion(-)

index 131394f..4bec7a5 100644
@@ -237,6 +237,7 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
 	acpi_osi=	[HW,ACPI] Modify list of supported OS interface strings
 			acpi_osi="string1"	# add string1
 			acpi_osi="!string2"	# remove string2
+			acpi_osi=!*		# remove all strings
 			acpi_osi=!		# disable all built-in OS vendor
 						  strings
 			acpi_osi=		# disable all strings

@@ -248,7 +249,9 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
 			it cannot affect the default state of the feature group
 			strings and the current state of the OS vendor strings,
 			specifying it multiple times through kernel command line
-			is meaningless.
+			is meaningless.  This command is useful when one do not
+			care about the state of the feature group strings which
+			should be controlled by the OSPM.
 			Examples:
 			  1. 'acpi_osi=! acpi_osi="Windows 2000"' is equivalent
 			     to 'acpi_osi="Windows 2000" acpi_osi=!', they all

@@ -264,6 +267,29 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
 			  1. 'acpi_osi=' can make 'CondRefOf(_OSI, Local1)'
 			     FALSE.
 
+			'acpi_osi=!*' can be used in combination with single or
+			multiple 'acpi_osi="string1"' to support specific
+			string(s).  Note that such command can affect the
+			current state of both the OS vendor strings and the
+			feature group strings, thus specifying it multiple times
+			through kernel command line is meaningful.  But it may
+			still not able to affect the final state of a string if
+			there are quirks related to this string.  This command
+			is useful when one want to control the state of the
+			feature group strings to debug BIOS issues related to
+			the OSPM features.
+			Examples:
+			  1. 'acpi_osi="Module Device" acpi_osi=!*' can make
+			     '_OSI("Module Device")' FALSE.
+			  2. 'acpi_osi=!* acpi_osi="Module Device"' can make
+			     '_OSI("Module Device")' TRUE.
+			  3. 'acpi_osi=! acpi_osi=!* acpi_osi="Windows 2000"' is
+			     equivalent to
+			     'acpi_osi=!* acpi_osi=! acpi_osi="Windows 2000"'
+			     and
+			     'acpi_osi=!* acpi_osi="Windows 2000" acpi_osi=!',
+			     they all will make '_OSI("Windows 2000")' TRUE.
+
 	acpi_pm_good	[X86]
 			Override the pmtimer bug detection: force the kernel
 			to assume that this machine's pmtimer latches its value

index 5dc311d..4b75e46 100644
@@ -1390,6 +1390,13 @@ void __init acpi_osi_setup(char *str)
 		if (*str == '\0') {
 			osi_linux.default_disabling = 1;
 			return;
+		} else if (*str == '*') {
+			acpi_update_interfaces(ACPI_DISABLE_ALL_STRINGS);
+			for (i = 0; i < OSI_STRING_ENTRIES_MAX; i++) {
+				osi = &osi_setup_entries[i];
+				osi->enable = false;
+			}
+			return;
 		}
 		enable = false;
 	}

1.7.10