diff options
| author | Marco Elver <elver@google.com> | 2025-12-19 16:39:51 +0100 |
|---|---|---|
| committer | Peter Zijlstra <peterz@infradead.org> | 2026-01-05 16:43:26 +0100 |
| commit | 3269701cb25662ae8a9771a864201116626adb50 (patch) | |
| tree | 24a0ad9e25bd5a97064ab689d5466c347eacd72a /scripts | |
| parent | de15fecae44df8254fa597bad7eb3680a8b1c10c (diff) | |
compiler-context-analysis: Add infrastructure for Context Analysis with Clang
Context Analysis is a language extension, which enables statically
checking that required contexts are active (or inactive), by acquiring
and releasing user-definable "context locks". An obvious application is
lock-safety checking for the kernel's various synchronization primitives
(each of which represents a "context lock"), and checking that locking
rules are not violated.
Clang originally called the feature "Thread Safety Analysis" [1]. This
was later changed and the feature became more flexible, gaining the
ability to define custom "capabilities". Its foundations can be found in
"Capability Systems" [2], used to specify the permissibility of
operations to depend on some "capability" being held (or not held).
Because the feature is not just able to express "capabilities" related
to synchronization primitives, and "capability" is already overloaded in
the kernel, the naming chosen for the kernel departs from Clang's
"Thread Safety" and "capability" nomenclature; we refer to the feature
as "Context Analysis" to avoid confusion. The internal implementation
still makes references to Clang's terminology in a few places, such as
`-Wthread-safety` being the warning option that also still appears in
diagnostic messages.
[1] https://clang.llvm.org/docs/ThreadSafetyAnalysis.html
[2] https://www.cs.cornell.edu/talc/papers/capabilities.pdf
See more details in the kernel-doc documentation added in this and
subsequent changes.
Clang version 22+ is required.
[peterz: disable the thing for __CHECKER__ builds]
Signed-off-by: Marco Elver <elver@google.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://patch.msgid.link/20251219154418.3592607-3-elver@google.com
Diffstat (limited to 'scripts')
| -rw-r--r-- | scripts/Makefile.context-analysis | 7 | ||||
| -rw-r--r-- | scripts/Makefile.lib | 10 |
2 files changed, 17 insertions, 0 deletions
diff --git a/scripts/Makefile.context-analysis b/scripts/Makefile.context-analysis new file mode 100644 index 000000000000..70549f7fae1a --- /dev/null +++ b/scripts/Makefile.context-analysis @@ -0,0 +1,7 @@ +# SPDX-License-Identifier: GPL-2.0 + +context-analysis-cflags := -DWARN_CONTEXT_ANALYSIS \ + -fexperimental-late-parse-attributes -Wthread-safety \ + -Wthread-safety-pointer -Wthread-safety-beta + +export CFLAGS_CONTEXT_ANALYSIS := $(context-analysis-cflags) diff --git a/scripts/Makefile.lib b/scripts/Makefile.lib index 28a1c08e3b22..e429d68b8594 100644 --- a/scripts/Makefile.lib +++ b/scripts/Makefile.lib @@ -106,6 +106,16 @@ _c_flags += $(if $(patsubst n%,, \ endif # +# Enable context analysis flags only where explicitly opted in. +# (depends on variables CONTEXT_ANALYSIS_obj.o, CONTEXT_ANALYSIS) +# +ifeq ($(CONFIG_WARN_CONTEXT_ANALYSIS),y) +_c_flags += $(if $(patsubst n%,, \ + $(CONTEXT_ANALYSIS_$(target-stem).o)$(CONTEXT_ANALYSIS)$(if $(is-kernel-object),$(CONFIG_WARN_CONTEXT_ANALYSIS_ALL))), \ + $(CFLAGS_CONTEXT_ANALYSIS)) +endif + +# # Enable AutoFDO build flags except some files or directories we don't want to # enable (depends on variables AUTOFDO_PROFILE_obj.o and AUTOFDO_PROFILE). # |