ACPI: LPIT: Avoid u32 multiplication overflow

In lpit_update_residency() there is a possibility of overflow
in multiplication, if tsc_khz is large enough (> UINT_MAX/1000).

Change multiplication to mul_u32_u32().

Found by Linux Verification Center (linuxtesting.org) with SVACE.

Fixes: eeb2d80d502a ("ACPI / LPIT: Add Low Power Idle Table (LPIT) support")
Signed-off-by: Nikita Kiryushin <kiryushin@ancud.ru>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

ACPI: LPIT: move to use bus_get_dev_root()

Direct access to the struct bus_type dev_root pointer is going away soon
so replace that with a call to bus_get_dev_root() instead, which is what
it is there for.

Cc: Len Brown <lenb@kernel.org>
Cc: linux-acpi@vger.kernel.org
Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Link: https://lore.kernel.org/r/20230322083646.2937580-1-gregkh@linuxfoundation.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

ACPI: Silence missing prototype warnings

Compiling with clang-16:

drivers/acpi/acpi_lpit.c:142:6: error: no previous prototype \
for function 'acpi_init_lpit' [-Werror,-Wmissing-prototypes]

drivers/acpi/ioapic.c:212:6: error: no previous prototype \
for function 'pci_ioapic_remove' [-Werror,-Wmissing-prototypes]

drivers/acpi/ioapic.c:229:5: error: no previous prototype \
for function 'acpi_ioapic_remove' [-Werror,-Wmissing-prototypes]

Include "internal.h" to silence them.

Signed-off-by: Ammar Faizi <ammarfaizi2@gnuweeb.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

Revert "ACPI / PM: LPIT: Register sysfs attributes based on FADT"

Revert commit 1cdda9486f51 ("ACPI / PM: LPIT: Register sysfs attributes
based on FADT"), because what it did was more confusing than it would
be to allow the sysfs attributes in question to be created regardless
of whether or not the relevant flag was set in the FADT.

If ACPI_FADT_LOW_POWER_S0 is not set, it need not mean that LPIT is
invalid and low-power S0 idle is not usable. It merely means that
using S3 on the given system is more beneficial from the energy
saving perspective than using low-power S0 idle.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Reviewed-by: Mario Limonciello <mario.limonciello@amd.com>

ACPI: LPIT: Put the low power idle table after using it

The mapped LPIT table is not used for runtime after init,
put the ACPI table to release the table mapping.

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

remove ioremap_nocache and devm_ioremap_nocache

ioremap has provided non-cached semantics by default since the Linux 2.6
days, so remove the additional ioremap_nocache interface.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Arnd Bergmann <arnd@arndb.de>

treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 174

Based on 1 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
distributed in the hope that it will be useful but without any
warranty without even the implied warranty of merchantability or
fitness for a particular purpose see the gnu general public license
for more details

extracted by the scancode license scanner the SPDX license identifier

GPL-2.0-only

has been chosen to replace the boilerplate/reference in 655 file(s).

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Allison Randal <allison@lohutok.net>
Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org>
Reviewed-by: Richard Fontana <rfontana@redhat.com>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190527070034.575739538@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

ACPI / LPIT: Correct LPIT end address for lpit_process()

Correct the LPIT end address which is passed into lpit_process()
and the end address limit test in lpit_process().

The LPI state descriptor subtables follow the fixed sized
acpi_lpit_header up to the end of the LPIT. The last LPI state
descriptor can end at exactly the end of the LPIT.

Note that this is a fix to a latent problem. Although incorrect,
the unpatched version works because the passed in end address
is just slightly beyond the actual end of the LPIT and the size
of the ACPI LPIT header is smaller than the size of the only
currently defined LPI state descriptor, acpi_lpit_native.

Signed-off-by: Lenny Szubowicz <lszubowi@redhat.com>
Reviewed-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

ACPI / PM: LPIT: Register sysfs attributes based on FADT

ACPI Low Power S0 Idle capabilities are announced via FADT table and can
be used to inform the kernel about the presence of one or more Low Power
Idle (LPI) entries as descried in LPIT table. LPIT table can exist
independently even if the FADT S0 Idle flag is not set and thus it could
confuse user since the following cpuidle attributes are created.

/sys/devices/system/cpu/cpuidle/low_power_idle_cpu_residency_us
/sys/devices/system/cpu/cpuidle/low_power_idle_system_residency_us

Presence or absence of above attributes could mean that the given
platform supports S0ix state or not.

This change allows to create the above cpuidle attributes only if
FADT table supports Low Power S0 Idle.

Signed-off-by: Rajneesh Bhardwaj <rajneesh.bhardwaj@linux.intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

ACPI / LPIT: Export lpit_read_residency_count_address()

Export lpit_read_residency_count_address(), so that it can be used from
drivers built as module. With the recent changes, the builtin_pci
functionality of the intel_pmc_core driver is removed and now it can be
built as a module to read this exported interface to calculate the PMC base
address.

Cc: Rafael J. Wysocki <rjw@rjwysocki.net>
Cc: Len Brown <lenb@kernel.org>
Cc: linux-acpi@vger.kernel.org

Acked-by: Rafael J. Wysocki <rafael@kernel.org>
Tested-by: Rajneesh Bhardwaj <rajneesh.bhardwaj@intel.com>
Signed-off-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>

ACPI / LPIT: Add Low Power Idle Table (LPIT) support

Add functionality to read LPIT table, which provides:

- Sysfs interface to read residency counters via
/sys/devices/system/cpu/cpuidle/low_power_idle_cpu_residency_us
/sys/devices/system/cpu/cpuidle/low_power_idle_system_residency_us

Here the count "low_power_idle_cpu_residency_us" shows the time spent
by CPU package in low power state. This is read via MSR interface,
which points to MSR for PKG C10.

Here the count "low_power_idle_system_residency_us" show the count the
system was in low power state. This is read via MMIO interface. This
is mapped to SLP_S0 residency on modern Intel systems. This residency
is achieved only when CPU is in PKG C10 and all functional blocks are
in low power state.

It is possible that none of the above counters present or anyone of the
counter present or all counters present.

For example: On my Kabylake system both of the above counters present.
After suspend to idle these counts updated and prints:

6916179
6998564

This counter can be read by tools like turbostat to display. Or it can
be used to debug, if modern systems are reaching desired low power state.

- Provides an interface to read residency counter memory address

This address can be used to get the base address of PMC memory
mapped IO. This is utilized by intel_pmc_core driver to print
more debug information.

In addition, to avoid code duplication to read iomem, removed the read of
iomem from acpi_os_read_memory() in osl.c and made a common function
acpi_os_read_iomem(). This new function is used for reading iomem in
in both osl.c and acpi_lpit.c.

Link: http://www.uefi.org/sites/default/files/resources/Intel_ACPI_Low_Power_S0_Idle.pdf
Signed-off-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>