Commit 30c9bb0d authored May 03, 2016 by Lv Zheng Committed by Rafael J. Wysocki May 05, 2016

ACPI / osi: Fix an issue that acpi_osi=!* cannot disable ACPICA internal strings



The order of the _OSI related functionalities is as follows:

  acpi_blacklisted()
    acpi_dmi_osi_linux()
      acpi_osi_setup()
    acpi_osi_setup()
      acpi_update_interfaces() if "!*"
      <<<<<<<<<<<<<<<<<<<<<<<<
  parse_args()
    __setup("acpi_osi=")
      acpi_osi_setup_linux()
        acpi_update_interfaces() if "!*"
        <<<<<<<<<<<<<<<<<<<<<<<<
  acpi_early_init()
    acpi_initialize_subsystem()
      acpi_ut_initialize_interfaces()
      ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  acpi_bus_init()
    acpi_os_initialize1()
      acpi_install_interface_handler(acpi_osi_handler)
      acpi_osi_setup_late()
        acpi_update_interfaces() for "!"
        >>>>>>>>>>>>>>>>>>>>>>>>
  acpi_osi_handler()

Since acpi_osi_setup_linux() can override acpi_dmi_osi_linux(), the command
line setting can override the DMI detection. That's why acpi_blacklisted()
is put before __setup("acpi_osi=").

Then we can notice the following wrong invocation order. There are
acpi_update_interfaces() (marked by <<<<) calls invoked before
acpi_ut_initialize_interfaces() (marked by ^^^^). This makes it impossible
to use acpi_osi=!* correctly from OSI DMI table or from the command line.
The use of acpi_osi=!* is meant to disable both ACPICA
(acpi_gbl_supported_interfaces) and Linux specific strings
(osi_setup_entries) while the ACPICA part should have stopped working
because of the order issue.

This patch fixes this issue by moving acpi_update_interfaces() to where
it is invoked for acpi_osi=! (marked by >>>>) as this is ensured to be
invoked after acpi_ut_initialize_interfaces() (marked by ^^^^). Linux
specific strings are still handled in the original place in order to make
the following command line working: acpi_osi=!* acpi_osi="Module Device".

Note that since acpi_osi=!* is meant to further disable linux specific
string comparing to the acpi_osi=!, there is no such use case in our bug
fixing work and hence there is no one using acpi_osi=!* either from the
command line or from the DMI quirks, this issue is just a theoretical
issue.

Fixes: 741d8128 (ACPI: Add facility to remove all _OSI strings)
Cc: 3.12+ <stable@vger.kernel.org> # 3.12+
Tested-by: Lukas Wunner <lukas@wunner.de>
Tested-by: Chen Yu <yu.c.chen@intel.com>
Signed-off-by: Lv Zheng <lv.zheng@intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

parent 04974df8

drivers/acpi/osl.c

+11 −5

Original line number	Original line	Diff line number	Diff line
	@@ -135,7 +135,7 @@ static struct osi_linux {
	unsigned int enable:1;		unsigned int enable:1;
	unsigned int dmi:1;		unsigned int dmi:1;
	unsigned int cmdline:1;		unsigned int cmdline:1;
	unsigned int default_disabling:1;		u8 default_disabling;
	} osi_linux = {0, 0, 0, 0};		} osi_linux = {0, 0, 0, 0};

	static u32 acpi_osi_handler(acpi_string interface, u32 supported)		static u32 acpi_osi_handler(acpi_string interface, u32 supported)
	@@ -1751,10 +1751,13 @@ void __init acpi_osi_setup(char *str)
	if (*str == '!') {		if (*str == '!') {
	str++;		str++;
	if (*str == '\0') {		if (*str == '\0') {
	osi_linux.default_disabling = 1;		/* Do not override acpi_osi=!* */
			if (!osi_linux.default_disabling)
			osi_linux.default_disabling =
			ACPI_DISABLE_ALL_VENDOR_STRINGS;
	return;		return;
	} else if (str == '') {		} else if (str == '') {
	acpi_update_interfaces(ACPI_DISABLE_ALL_STRINGS);		osi_linux.default_disabling = ACPI_DISABLE_ALL_STRINGS;
	for (i = 0; i < OSI_STRING_ENTRIES_MAX; i++) {		for (i = 0; i < OSI_STRING_ENTRIES_MAX; i++) {
	osi = &osi_setup_entries[i];		osi = &osi_setup_entries[i];
	osi->enable = false;		osi->enable = false;
	@@ -1827,10 +1830,13 @@ static void __init acpi_osi_setup_late(void)
	acpi_status status;		acpi_status status;

	if (osi_linux.default_disabling) {		if (osi_linux.default_disabling) {
	status = acpi_update_interfaces(ACPI_DISABLE_ALL_VENDOR_STRINGS);		status = acpi_update_interfaces(osi_linux.default_disabling);

	if (ACPI_SUCCESS(status))		if (ACPI_SUCCESS(status))
	printk(KERN_INFO PREFIX "Disabled all _OSI OS vendors\n");		printk(KERN_INFO PREFIX "Disabled all _OSI OS vendors%s\n",
			osi_linux.default_disabling ==
			ACPI_DISABLE_ALL_STRINGS ?
			" and feature groups" : "");
	}		}

	for (i = 0; i < OSI_STRING_ENTRIES_MAX; i++) {		for (i = 0; i < OSI_STRING_ENTRIES_MAX; i++) {