The decrementation of acpi_device_bus_id->instance_no
in acpi_device_del() is incorrect, because it may cause
a duplicate instance number to be allocated next time
a device with the same acpi_device_bus_id is added.

Replace above mentioned approach by using IDA framework.

While at it, define the instance range to be [0, 4096).

Fixes: e49bd2dd5a50 ("ACPI: use PNPID:instance_no as bus_id of ACPI device")
Fixes: ca9dc8d42b30 ("ACPI / scan: Fix acpi_bus_id_list bookkeeping")
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: 4.10+ <stable@vger.kernel.org> # 4.10+
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

Linux VM on Hyper-V crashes with the latest mainline:

[    4.069624] detected buffer overflow in strcpy
[    4.077733] kernel BUG at lib/string.c:1149!
..
[    4.085819] RIP: 0010:fortify_panic+0xf/0x11
...
[    4.085819] Call Trace:
[    4.085819]  acpi_device_add.cold.15+0xf2/0xfb
[    4.085819]  acpi_add_single_object+0x2a6/0x690
[    4.085819]  acpi_bus_check_add+0xc6/0x280
[    4.085819]  acpi_ns_walk_namespace+0xda/0x1aa
[    4.085819]  acpi_walk_namespace+0x9a/0xc2
[    4.085819]  acpi_bus_scan+0x78/0x90
[    4.085819]  acpi_scan_init+0xfa/0x248
[    4.085819]  acpi_init+0x2c1/0x321
[    4.085819]  do_one_initcall+0x44/0x1d0
[    4.085819]  kernel_init_freeable+0x1ab/0x1f4

This is because of the recent buffer overflow detection in the
commit 6a39e62abbaf ("lib: string.h: detect intra-object overflow in
fortified string functions")

Here acpi_device_bus_id->bus_id can only hold 14 characters, while the
the acpi_device_hid(device) returns a 22-char string
"HYPER_V_GEN_COUNTER_V1".

Per ACPI Spec v6.2, Section 6.1.5 _HID (Hardware ID), if the ID is a
string, it must be of the form AAA#### or NNNN####, i.e. 7 chars or 8
chars.

The field bus_id in struct acpi_device_bus_id was originally defined as
char bus_id[9], and later was enlarged to char bus_id[15] in 2007 in the
commit bb0958544f3c ("ACPI: use more understandable bus_id for ACPI
devices")

Fix the issue by changing the field bus_id to const char *, and use
kstrdup_const() to initialize it.

Signed-off-by: Dexuan Cui <decui@microsoft.com>
Tested-By: Jethro Beekman <jethro@fortanix.com>
[ rjw: Subject change, whitespace adjustment ]
Cc: All applicable <stable@vger.kernel.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

* acpica:
  ACPICA: Update version to 20201113
  ACPICA: Interpreter: fix memory leak by using existing buffer
  ACPICA: Add function trace macros to improve debugging
  ACPICA: Also handle "orphan" _REG methods for GPIO OpRegions
  ACPICA: Remove extreaneous "the" in comments
  ACPICA: Add 5 new UUIDs to the known UUID table

* acpi-scan:
  ACPI: scan: Fix up _DEP-related terminology with supplier/consumer
  ACPI: scan: Drop INT3396 from acpi_ignore_dep_ids[]
  ACPI: scan: Add PNP0D80 to the _DEP exceptions list
  ACPI: scan: Call acpi_get_object_info() from acpi_add_single_object()
  ACPI: scan: Add acpi_info_matches_hids() helper

Call acpi_get_object_info() from acpi_add_single_object() instead of
calling it from acpi_set_pnp_ids() and pass the result down to the
latter so as to allow acpi_add_single_object() to use that data for
other purposes.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
[ rjw: Changelog rewrite ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

Replaces spaces with tabs where spaces have been (inconsistently) used
for indentation and removes trailing whitespaces.

Signed-off-by: Maximilian Luz <luzmaximilian@gmail.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

If the EC GPE status is not set after checking all of the other GPEs,
acpi_s2idle_wake() returns 'false', to indicate that the SCI event
that has just triggered is not a system wakeup one, but it does that
without canceling the pending wakeup and re-arming the SCI for system
wakeup which is a mistake, because it may cause s2idle_loop() to busy
spin until the next valid wakeup event.  [If that happens, the first
spurious wakeup is still pending after acpi_s2idle_wake() has
returned, so s2idle_enter() does nothing, acpi_s2idle_wake()
is called again and it sees that the SCI has triggered, but no GPEs
are active, so 'false' is returned again, and so on.]

Fix that by moving all of the GPE checking logic from
acpi_s2idle_wake() to acpi_ec_dispatch_gpe() and making the
latter return 'true' only if a non-EC GPE has triggered and
'false' otherwise, which will cause acpi_s2idle_wake() to
cancel the pending SCI wakeup and re-arm the SCI for system
wakeup regardless of the EC GPE status.

This also addresses a lockup observed on an Elitegroup EF20EA laptop
after attempting to wake it up from suspend-to-idle by a key press.

Fixes: d5406284ff80 ("ACPI: PM: s2idle: Refine active GPEs check")
Link: https://bugzilla.kernel.org/show_bug.cgi?id=207603
Reported-by: Todd Brandt <todd.e.brandt@linux.intel.com>
Fixes: fdde0ff8590b ("ACPI: PM: s2idle: Prevent spurious SCIs from waking up the system")
Link: https://lore.kernel.org/linux-acpi/CAB4CAwdqo7=MvyG_PE+PGVfeA17AHF5i5JucgaKqqMX6mjArbQ@mail.gmail.com/
Reported-by: Chris Chiu <chiu@endlessm.com>
Tested-by: Chris Chiu <chiu@endlessm.com>
Cc: 5.4+ <stable@vger.kernel.org> # 5.4+
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

Pull ACPI updates from Rafael Wysocki:

   - Update the ACPICA code in the kernel to the 20200214 upstream
     release including:

       * Fix to re-enable the sleep button after wakeup (Anchal
         Agarwal).

       * Fixes for mistakes in comments and typos (Bob Moore).

       * ASL-ASL+ converter updates (Erik Kaneda).

       * Type casting cleanups (Sven Barth).

   - Clean up the intialization of the EC driver and eliminate some dead
     code from it (Rafael Wysocki).

   - Clean up the quirk tables in the AC and battery drivers (Hans de
     Goede).

   - Fix the global lock handling on x86 to ignore unspecified bit
     positions in the global lock field (Jan Engelhardt).

   - Add a new "tiny" driver for ACPI button devices exposed by VMs to
     guest kernels to send signals directly to init (Josh Triplett).

   - Add a kernel parameter to disable ACPI BGRT on x86 (Alex Hung).

   - Make the ACPI PCI host bridge and fan drivers use scnprintf() to
     avoid potential buffer overflows (Takashi Iwai).

   - Clean up assorted pieces of code:

       * Reorder "asmlinkage" to make g++ happy (Alexey Dobriyan).

       * Drop unneeded variable initialization (Colin Ian King).

       * Add missing __acquires/__releases annotations (Jules Irenge).

       * Replace list_for_each_safe() with list_for_each_entry_safe()
         (chenqiwu)"

* tag 'acpi-5.7-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm: (31 commits)
  ACPICA: Update version to 20200214
  ACPI: PCI: Use scnprintf() for avoiding potential buffer overflow
  ACPI: fan: Use scnprintf() for avoiding potential buffer overflow
  ACPI: EC: Eliminate EC_FLAGS_QUERY_HANDSHAKE
  ACPI: EC: Do not clear boot_ec_is_ecdt in acpi_ec_add()
  ACPI: EC: Simplify acpi_ec_ecdt_start() and acpi_ec_init()
  ACPI: EC: Consolidate event handler installation code
  acpi/x86: ignore unspecified bit positions in the ACPI global lock field
  acpi/x86: add a kernel parameter to disable ACPI BGRT
  x86/acpi: make "asmlinkage" part first thing in the function definition
  ACPI: list_for_each_safe() -> list_for_each_entry_safe()
  ACPI: video: remove redundant assignments to variable result
  ACPI: OSL: Add missing __acquires/__releases annotations
  ACPI / battery: Cleanup Lenovo Ideapad Miix 320 DMI table entry
  ACPI / AC: Cleanup DMI quirk table
  ACPI: EC: Use fast path in acpi_ec_add() for DSDT boot EC
  ACPI: EC: Simplify acpi_ec_add()
  ACPI: EC: Drop AE_NOT_FOUND special case from ec_install_handlers()
  ACPI: EC: Avoid passing redundant argument to functions
  ACPI: EC: Avoid printing confusing messages in acpi_ec_setup()
  ...

The check for any active GPEs added by commit fdde0ff8590b ("ACPI:
PM: s2idle: Prevent spurious SCIs from waking up the system") turns
out to be insufficiently precise to prevent some systems from
resuming prematurely due to a spurious EC wakeup, so refine it
by first checking if any GPEs other than the EC GPE are active
and skipping all of the SCIs coming from the EC that do not produce
any genuine wakeup events after processing.

Link: https://bugzilla.kernel.org/show_bug.cgi?id=206629
Fixes: fdde0ff8590b ("ACPI: PM: s2idle: Prevent spurious SCIs from waking up the system")
Reported-by: Ondřej Caletka <ondrej@caletka.cz>
Tested-by: Ondřej Caletka <ondrej@caletka.cz>
Cc: 5.4+ <stable@vger.kernel.org> # 5.4+
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

Notice that the return value of acpi_ec_init() is discarded anyway,
so it can be void and it doesn't need to check the return values of
acpi_bus_register_driver() and acpi_ec_ecdt_start() called by it.
Thus the latter can be void too and it really has nothing to do
if acpi_ec_add() has already found an EC matching the boot one in the
namespace.  Also, acpi_ec_ecdt_get_handle() can be folded into it.

Modify the code accordingly and while at it create a propoer kerneldoc
comment to document acpi_ec_ecdt_start() and move the remark regarding
ASUS X550ZE along with the related bug URL from acpi_ec_init() into
that comment.

Additionally, fix up a stale comment in acpi_ec_init().

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

As defined in the ACPI spec section 12.11, ACPI hardware-reduced
platforms define the EC SCI interrupt as a GpioInt in the _CRS object.

This replaces the previous way of using a GPE for this interrupt;
GPE blocks are not available on reduced hardware platforms.

Add support for handling this interrupt as an EC event source, and
avoid GPE usage on reduced hardware platforms.

This enables the use of several media keys (e.g. screen brightness
up/down) on Asus UX434DA.

Signed-off-by: Daniel Drake <drake@endlessm.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>