[PATCH 4.6 034/100] ACPI / osi: Fix an issue that acpi_osi=!* cannot disable ACPICA internal strings

Greg Kroah-Hartman
2016-05-30T21:40:46Z

From: Lv Zheng <lv.zheng@intel.com>

commit 30c9bb0d7603e7b3f4d6a0ea231e1cddae020c32 upstream.

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: 741d81280ad2 (ACPI: Add facility to remove all _OSI strings)
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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
drivers/acpi/osl.c | 16 +++++++++++-----
1 file changed, 11 insertions(+), 5 deletions(-)

--- a/drivers/acpi/osl.c
+++ b/drivers/acpi/osl.c
@@ -135,7 +135,7 @@ static struct osi_linux {
unsigned int enable:1;
unsigned int dmi:1;
unsigned int cmdline:1;
- unsigned int default_disabling:1;
+ u8 default_disabling;
} osi_linux = {0, 0, 0, 0};

static u32 acpi_osi_handler(acpi_string interface, u32 supported)
@@ -1751,10 +1751,13 @@ void __init acpi_osi_setup(char *str)
if (*str == '!') {
str++;
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;
} 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++) {
osi = &osi_setup_entries[i];
osi->enable = false;
@@ -1827,10 +1830,13 @@ static void __init acpi_osi_setup_late(v
acpi_status status;

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))
- 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++) {