ACPICA commit 4b9135f5774caa796ddf826448811e8e7f08ef2f
GCC 7.1 gained -Wimplicit-fallthrough to warn on implicit fallthrough,
as well as __attribute__((__fallthrough__)) and comments to explicitly
denote that cases of fallthrough were intentional. Clang also supports
this warning and statement attribute, but not the comment form.
Robert Moore provides additional context about the lint comments being
removed. They were for "an old version of PC-Lint, which we don't use
anymore." Drop those.
This will help us enable -Wimplicit-fallthrough throughout the Linux
kernel.
Suggested-by: Robert Moore <robert.moore@intel.com>
Reported-by: Jon Hunter <jonathanh@nvidia.com>
Link: https://github.com/acpica/acpica/commit/4b9135f5
Signed-off-by: Nick Desaulniers <ndesaulniers@google.com>
Signed-off-by: Bob Moore <robert.moore@intel.com>
Signed-off-by: Erik Kaneda <erik.kaneda@intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
ACPICA commit 7ba2f3d91a32f104765961fda0ed78b884ae193d
The current codebase makes use of one-element arrays in the following
form:
struct something {
int length;
u8 data[1];
};
struct something *instance;
instance = kmalloc(sizeof(*instance) + size, GFP_KERNEL);
instance->length = size;
memcpy(instance->data, source, size);
but the preferred mechanism to declare variable-length types such as
these ones is a flexible array member[1][2], introduced in C99:
struct foo {
int stuff;
struct boo array[];
};
By making use of the mechanism above, we will get a compiler warning
in case the flexible array does not occur last in the structure,
which will help us prevent some kind of undefined behavior bugs from
being inadvertently introduced[3] to the linux codebase from now on.
This issue was found with the help of Coccinelle and audited _manually_.
[1] https://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html
[2] https://github.com/KSPP/linux/issues/21
[3] commit 7649773293 ("cxgb3/l2t: Fix undefined behaviour")
Link: https://github.com/acpica/acpica/commit/7ba2f3d9
Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
Signed-off-by: Erik Kaneda <erik.kaneda@intel.com>
Signed-off-by: Bob Moore <robert.moore@intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
The ACPICA's strategy with respect to the handling of memory mappings
associated with memory operation regions is to avoid mapping the
entire region at once which may be problematic at least in principle
(for example, it may lead to conflicts with overlapping mappings
having different attributes created by drivers). It may also be
wasteful, because memory opregions on some systems take up vast
chunks of address space while the fields in those regions actually
accessed by AML are sparsely distributed.
For this reason, a one-page "window" is mapped for a given opregion
on the first memory access through it and if that "window" does not
cover an address range accessed through that opregion subsequently,
it is unmapped and a new "window" is mapped to replace it. Next,
if the new "window" is not sufficient to acess memory through the
opregion in question in the future, it will be replaced with yet
another "window" and so on. That may lead to a suboptimal sequence
of memory mapping and unmapping operations, for example if two fields
in one opregion separated from each other by a sufficiently wide
chunk of unused address space are accessed in an alternating pattern.
The situation may still be suboptimal if the deferred unmapping
introduced previously is supported by the OS layer. For instance,
the alternating memory access pattern mentioned above may produce
a relatively long list of mappings to release with substantial
duplication among the entries in it, which could be avoided if
acpi_ex_system_memory_space_handler() did not release the mapping
used by it previously as soon as the current access was not covered
by it.
In order to improve that, modify acpi_ex_system_memory_space_handler()
to preserve all of the memory mappings created by it until the memory
regions associated with them go away.
Accordingly, update acpi_ev_system_memory_region_setup() to unmap all
memory associated with memory opregions that go away.
Reported-by: Dan Williams <dan.j.williams@intel.com>
Tested-by: Xiang Li <xiang.z.li@intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
No need for the array of structs of function pointers when we can just
call the handfull of functions directly.
This could be further cleaned up if acpi_gbl_reduced_hardware was defined
true in the ACPI_REDUCED_HARDWARE case, but that's material for the next
round.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Provide a new lock type acpi_raw_spinlock which is implemented as
raw_spinlock_t on Linux. This type should be used in code which covers
small areas of code and disables interrupts only for short time even on
a realtime OS.
There is a fallback to spinlock_t if an OS does not provide an
implementation for acpi_raw_spinlock.
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
