kmsan: increase the maximum store size to 4096

The inline assembly block in s390's chsc() stores that much.

Link: https://lkml.kernel.org/r/20240621113706.315500-5-iii@linux.ibm.com
Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com>
Reviewed-by: Alexander Potapenko <glider@google.com>
Cc: Alexander Gordeev <agordeev@linux.ibm.com>
Cc: Christian Borntraeger <borntraeger@linux.ibm.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Hyeonggon Yoo <42.hyeyoo@gmail.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: <kasan-dev@googlegroups.com>
Cc: Marco Elver <elver@google.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Steven Rostedt (Google) <rostedt@goodmis.org>
Cc: Sven Schnelle <svens@linux.ibm.com>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

diff --git a/mm/kmsan/instrumentation.c b/mm/kmsan/instrumentation.c
index cc3907a9c33a0c3d4e08faaa611b62eb6e2f4282..470b0b4afcc45980af5f50c37f3dde5d8ac15d79 100644 (file)
--- a/mm/kmsan/instrumentation.c
+++ b/mm/kmsan/instrumentation.c
@@ -110,11 +110,10 @@ void __msan_instrument_asm_store(void *addr, uintptr_t size)
 
        ua_flags = user_access_save();
        /*
-        * Most of the accesses are below 32 bytes. The two exceptions so far
-        * are clwb() (64 bytes) and FPU state (512 bytes).
-        * It's unlikely that the assembly will touch more than 512 bytes.
+        * Most of the accesses are below 32 bytes. The exceptions so far are
+        * clwb() (64 bytes), FPU state (512 bytes) and chsc() (4096 bytes).
         */
-       if (size > 512) {
+       if (size > 4096) {
                WARN_ONCE(1, "assembly store size too big: %ld\n", size);
                size = 8;
        }