ACPI: configfs: Make get_header() to return error pointer

Instead of duplicating error codes here and there,
make get_header() to return error pointer.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

ACPI: configfs: Use sysfs_emit() in "show" functions

The sysfs_emit() function was introduced to make it less ambiguous
which function is preferred when writing to the output buffer in
a "show" callback [1].

Convert the GPIO library sysfs interface from sprintf() to sysfs_emit()
accordingly, as the latter is aware of the PAGE_SIZE buffer and correctly
returns the number of bytes written into the buffer.

No functional change intended.

[1] Documentation/filesystems/sysfs.rst

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

ACPI: configfs: Replace ACPI_INFO() with pr_debug()

The ACPI_INFO() macro is used for message printing in the ACPICA code.

ACPI_INFO() will be empty if the ACPICA debug is not enabled, so
replace it with pr_debug().

Also remove the not needed ACPICA header file inclusions to decouple
from ACPICA.

Signed-off-by: Hanjun Guo <guohanjun@huawei.com>
[ rjw: Changelog edits ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

ACPI: configfs: add missing check after configfs_register_default_group()

A list_add corruption is reported by Hulk Robot like this:
==============
list_add corruption.
Call Trace:
link_obj+0xc0/0x1c0
link_group+0x21/0x140
configfs_register_subsystem+0xdb/0x380
acpi_configfs_init+0x25/0x1000 [acpi_configfs]
do_one_initcall+0x149/0x820
do_init_module+0x1ef/0x720
load_module+0x35c8/0x4380
__do_sys_finit_module+0x10d/0x1a0
do_syscall_64+0x34/0x80

It's because of the missing check after configfs_register_default_group,
where configfs_unregister_subsystem should be called once failure.

Fixes: 612bd01fc6e0 ("ACPI: add support for loading SSDTs via configfs")
Reported-by: Hulk Robot <hulkci@huawei.com>
Suggested-by: Hanjun Guo <guohanjun@huawei.com>
Signed-off-by: Qinglang Miao <miaoqinglang@huawei.com>
Cc: 4.10+ <stable@vger.kernel.org> # 4.10+
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

ACPI: configfs: Add missing config_item_put() to fix refcount leak

config_item_put() should be called in the drop_item callback, to
decrement refcount for the config item.

Fixes: 772bf1e2878ec ("ACPI: configfs: Unload SSDT on configfs entry removal")
Signed-off-by: Hanjun Guo <guohanjun@huawei.com>
[ rjw: Subject edit ]
Cc: 4.13+ <stable@vger.kernel.org> # 4.13+
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

ACPI: configfs: Disallow loading ACPI tables when locked down

Like other vectors already patched, this one here allows the root
user to load ACPI tables, which enables arbitrary physical address
writes, which in turn makes it possible to disable lockdown.

Prevents this by checking the lockdown status before allowing a new
ACPI table to be installed. The link in the trailer shows a PoC of
how this might be used.

Link: https://git.zx2c4.com/american-unsigned-language/tree/american-unsigned-language-2.sh
Cc: 5.4+ <stable@vger.kernel.org> # 5.4+
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

ACPICA: make acpi_load_table() return table index

ACPICA commit d1716a829d19be23277d9157c575a03b9abb7457

For unloading an ACPI table, it is necessary to provide the index of
the table. The method intended for dynamically loading or hotplug
addition of tables, acpi_load_table(), should provide this information
via an optional pointer to the loaded table index.

This patch fixes the table unload function of acpi_configfs.

Reported-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Fixes: d06c47e3dd07f ("ACPI: configfs: Resolve objects on host-directed table loads")
Link: https://github.com/acpica/acpica/commit/d1716a82
Signed-off-by: Nikolaus Voss <nikolaus.voss@loewensteinmedical.de>
Signed-off-by: Erik Schmauss <erik.schmauss@intel.com>
Signed-off-by: Bob Moore <robert.moore@intel.com>
Tested-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500

Based on 2 normalized pattern(s):

this program is free software you can redistribute it and or modify
it under the terms of the gnu general public license version 2 as
published by the free software foundation

this program is free software you can redistribute it and or modify
it under the terms of the gnu general public license version 2 as
published by the free software foundation #

extracted by the scancode license scanner the SPDX license identifier

GPL-2.0-only

has been chosen to replace the boilerplate/reference in 4122 file(s).

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Enrico Weigelt <info@metux.net>
Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org>
Reviewed-by: Allison Randal <allison@lohutok.net>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190604081206.933168790@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

ACPI: configfs: Resolve objects on host-directed table loads

If an ACPI SSDT overlay is loaded after built-in tables
have been loaded e.g. via configfs or efivar_ssdt_load()
it is necessary to rewalk the namespace to resolve
references. Without this, relative and absolute paths
like ^PCI0.SBUS or \_SB.PCI0.SBUS are not resolved
correctly.

Make configfs loads use the same method as efivar_ssdt_load().

Signed-off-by: Nikolaus Voss <nikolaus.voss@loewensteinmedical.de>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

ACPICA: Rename nameseg length macro/define for clarity

ACPICA commit 24870bd9e73d71e2a1ff0a1e94519f8f8409e57d

ACPI_NAME_SIZE changed to ACPI_NAMESEG_SIZE
This clarifies that this is the length of an individual
nameseg, not the length of a generic namestring/namepath.
Improves understanding of the code.

Link: https://github.com/acpica/acpica/commit/24870bd9
Signed-off-by: Bob Moore <robert.moore@intel.com>
Signed-off-by: Erik Schmauss <erik.schmauss@intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

ACPI / configfs: Mark local data structures static

There is no need to have non-static local data structures. otherwise
sparse is not happy:

CHECK drivers/acpi/acpi_configfs.c
drivers/acpi/acpi_configfs.c:100:31: warning: symbol 'acpi_table_bin_attrs' was not declared. Should it be static?
drivers/acpi/acpi_configfs.c:196:27: warning: symbol 'acpi_table_attrs' was not declared. Should it be static?
drivers/acpi/acpi_configfs.c:236:34: warning: symbol 'acpi_table_group_ops' was not declared. Should it be static?

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

ACPI / configfs: Mark local functions static

There is no need to have non-static local functions. otherwise
compiler is not happy:

CC [M] drivers/acpi/acpi_configfs.o
drivers/acpi/acpi_configfs.c:105:9: warning: no previous prototype for ‘acpi_table_signature_show’ [-Wmissing-prototypes]
ssize_t acpi_table_signature_show(struct config_item *cfg, char *str)
^~~~~~~~~~~~~~~~~~~~~~~~~
drivers/acpi/acpi_configfs.c:115:9: warning: no previous prototype for ‘acpi_table_length_show’ [-Wmissing-prototypes]
ssize_t acpi_table_length_show(struct config_item *cfg, char *str)
^~~~~~~~~~~~~~~~~~~~~~
...

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

ACPI: configfs: make config_item_type const

Make these structures const as they are either passed to the functions
having the argument as const or stored as a reference in the "ci_type"
const field of a config_item structure.

Done using Coccienlle.

Signed-off-by: Bhumika Goyal <bhumirks@gmail.com>
Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>

ACPI: configfs: Unload SSDT on configfs entry removal

Call directly into acpica to load a table to obtain its index on return.
We choose the direct call of acpica internal functions to avoid having
to modify its API which is used outside of Linux as well.

Use that index to unload the table again when the corresponding
directory in configfs gets removed. This allows to change SSDTs without
rebooting the system. It also allows to destroy devices again that a
dynamically loaded SSDT created.

This is widely similar to the DT overlay behavior.

Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

ACPI: Rename configfs.c to acpi_configfs.c to prevent link error

If we compile ACPI configfs.c as module it will confuse the linker as it
hides symbols from the actual configfs:

Kernel: arch/x86/boot/bzImage is ready (#1236)
MODPOST 5739 modules
ERROR: "configfs_unregister_subsystem" [samples/configfs/configfs_sample.ko] undefined!
ERROR: "configfs_register_subsystem" [samples/configfs/configfs_sample.ko] undefined!
ERROR: "config_group_init" [samples/configfs/configfs_sample.ko] undefined!
ERROR: "config_item_init_type_name" [samples/configfs/configfs_sample.ko] undefined!
ERROR: "config_group_init_type_name" [samples/configfs/configfs_sample.ko] undefined!
ERROR: "configfs_undepend_item" [fs/ocfs2/cluster/ocfs2_nodemanager.ko] undefined!
...

Prevent these by renaming the file to acpi_configfs.c instead.

Reported-by: Scott Lawson <scott.lawson@intel.com>
Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>