crypto: Enable context analysis

Enable context analysis for crypto subsystem.

This demonstrates a larger conversion to use Clang's context
analysis. The benefit is additional static checking of locking rules,
along with better documentation.

Note the use of the __acquire_ret macro how to define an API where a
function returns a pointer to an object (struct scomp_scratch) with a
lock held. Additionally, the analysis only resolves aliases where the
analysis unambiguously sees that a variable was not reassigned after
initialization, requiring minor code changes.

Signed-off-by: Marco Elver <elver@google.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://patch.msgid.link/20251219154418.3592607-36-elver@google.com

1 files changed, 2 insertions, 0 deletions

diff --git a/crypto/Makefile b/crypto/Makefile
index 16a35649dd91..db264feab7e7 100644
--- a/crypto/Makefile
+++ b/crypto/Makefile
@@ -3,6 +3,8 @@
 # Cryptographic API
 #
 
+CONTEXT_ANALYSIS := y
+
 obj-$(CONFIG_CRYPTO) += crypto.o
 crypto-y := api.o cipher.o