When vendor hooks are added to a file that previously didn't have any
vendor hooks, we end up indirectly including linux/tracepoint.h. This
causes some data types that used to be opaque (forward declared) to the
code to become visible to the code.
Modversions correctly catches this change in visibility, but we don't
really care about the data types made visible when linux/tracepoint.h is
included. So, hide this from modversions in the central vendor_hooks.h
file instead of having to fix this on a case by case basis.
Since this is a KMI frozen branch, existing vendor hook headers are left
as is to avoid KMI breakage due to CRC churn.
To avoid future pointless CRC churn, new vendor hook header files that
include vendor_hooks.h should not include linux/tracepoint.h directly.
Bug: 227513263
Bug: 226140073
Signed-off-by: Saravana Kannan <saravanak@google.com>
Change-Id: Ia88e6af11dd94fe475c464eb30a6e5e1e24c938b
commit 5e767aa07e ("ANDROID: use static_call() for restricted hooks")
introduced an implementation of __iteriter_##_name when
TRACE_HEADER_MULTI_READ is defined. __nocfi that function as well in
order to keep the performance optimizations from commit 384becf164
("ANDROID: Disable CFI on restricted vendor hooks").
Fixes: 384becf164 ("ANDROID: Disable CFI on restricted vendor hooks")
Change-Id: I6ea1cd767bad95c324c06398475174b710ae4dbe
Signed-off-by: Elliot Berman <quic_eberman@quicinc.com>
Allow up to two attachments to restricted vendor hooks to enable OEM
and vendor coexistence.
Priorities are not exposed to callers on purpose. Life's too short to
re-order the callback array with concurrent readers.
Bug: 183720636
Signed-off-by: Quentin Perret <qperret@google.com>
Change-Id: I5c7aca7f69e581b4197388478d47e0da6d2893e6
Vendor hooks required explicitly defining macros or inline functions
to handle the non-GKI build case (!CONFIG_ANDROID_VENDOR_HOOKS). Added
support for generating them automatically so the macros are no longer
required.
Both models are now supported so we can transition.
Bug: 177416721
Signed-off-by: Todd Kjos <tkjos@google.com>
Change-Id: I01acc389d315a5d509b0c48116854342a42e1058
CFI has additional overhead on indirect branches to modules as the
target is not known at kernel compile-time. This has been demonstrated
to cause problematic performance regressions on benchmarks using GKI
together with modularized scheduler callbacks attached to restricted
vendor hooks.
To restore some of the performance back, let's disable CFI around the
restricted hook call sites and issue a raw indirect call in fast paths.
We should be able to drop this patch when/if the arm64 static_call
port lands upstream [1] as this would make tracepoints circumvent some
of the CFI checks using text patching, but that still remain to be
proven.
[1] https://lore.kernel.org/linux-arm-kernel/20201028184114.6834-1-ardb@kernel.org/
Bug: 168521642
Change-Id: I7cd59f582b12fed15be64059f08122f96786e650
Signed-off-by: Quentin Perret <qperret@google.com>
After upstream 33def8498f ("treewide: Convert macro and uses of
__section(foo) to __section("foo")"), the preprocessor macro __section
now requires the section name to be double quoted.
This patch resolves breakage that results from merging down from
mainline in this out of tree header.
Fixes: 33def8498f ("treewide: Convert macro and uses of __section(foo) to __section("foo")")
Signed-off-by: Nick Desaulniers <ndesaulniers@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>
Change-Id: Ie6a701251e6420e63187a466b43ec2c834e0ec2e
commit d25e37d89d ("tracepoint: Optimize using static_call()")
refactored tracepoints to use static_call(). Add the same
optimization for restricted vendor hooks.
Fixes: d25e37d89d ("tracepoint: Optimize using static_call()")
Signed-off-by: Todd Kjos <tkjos@google.com>
Change-Id: I336db7e90b733ac4098ce342001cc31fd215d137
Because of the multi-inclusion oddities of tracepoints, the
multi-inclusion protection in vendor_hooks.h caused issues
if more than 1 vendor hook header file with restricted vendor
hooks defined were included with "CREATE_TRACE_POINTS"
defined (redefinition of symbol errors).
The problem is fixed by removing the multiple-inclusion
protection as is done for regular tracepoints.
Fixes: 7f62740112 ("ANDROID: add support for vendor hooks")
Bug: 163076069
Signed-off-by: Todd Kjos <tkjos@google.com>
Change-Id: Ic177db1693a6a2db58f08917e9115c7e6c2971b6
Add support for vendor hooks. Adds include/trace/hooks
directory for trace definition headers where hooks
can be defined and vendor_hook.c for instantiating
and exporting them for vendor modules.
There are two variants of vendor hooks, both based
on tracepoints:
Normal: this uses the DECLARE_HOOK macro
to create a tracepoint function with the name trace_<name>
where <name> is the unique identifier for the trace.
Restricted: restricted hooks are needed for cases like
scheduler hooks where the attached function must be
called even if the cpu is offline or requires a
non-atomic context. Restricted vendor hooks cannot
be detached, so modules that attach to a restricted
hook can never unload. Also, only 1 attachment is
allowed (any other attempts to attach will fail with
-EBUSY).
For either case, modules attach to the hook by using
register_trace_<name>(func_ptr, NULL).
New hooks should be defined in headers in the
include/trace/hooks/ directory using the
DECLARE_HOOK() or DECLARE_RESTRICTED_HOOK()
macros.
New files added to include/trace/hooks should
be #include'd from drivers/android/vendor_hooks.c.
The EXPORT_TRACEPOINT_SYMBOL_GPL() should be
also added to drivers/android/vendor_hooks.c.
For example, if a new hook, 'android_vh_foo(int &ret)'
is added in do_exit() in exit.c, these changes are
needed:
1. create a new header file include/trace/hooks/foo.h
which contains:
#include <trace/hooks/vendor_hooks.h>
...
DECLARE_HOOK(android_vh_foo,
TP_PROTO(int *retp),
TP_ARGS(retp);
2. in exit.c, add
#include <trace/hooks/foo.h>
...
int ret = 0;
...
android_vh_foo(&ret);
if (ret)
return ret;
...
3. in drivers/android/vendor_hooks.c, add
#include <trace/hooks/foo.h>
...
EXPORT_TRACEPOINT_SYMBOL_GPL(android_vh_foo);
The hook can then be attached by adding the registration code
to the module:
#include <trace/hooks/sched.h>
...
static void my_foo(int *retp)
{
*retp = 0;
}
...
rc = register_trace_android_vh_sched_exit(my_foo, NULL);
Bug: 156285741
Signed-off-by: Todd Kjos <tkjos@google.com>
Change-Id: I6a7d1c8919dae91c965e2a0450df50eac2d282db
