[PATCH v2 10/11] powerpc: powernv: Annotate asynchronous access to opal tokens
From: Rohan McLure <hidden>
Date: 2023-05-10 03:34:19
Subsystem:
linux for powerpc (32-bit and 64-bit), the rest · Maintainers:
Madhavan Srinivasan, Michael Ellerman, Linus Torvalds
The opal-async.c unit contains code for polling event sources, which
implies intentional data races. Ensure that the compiler will atomically
access such variables by means of {READ,WRITE}_ONCE calls, which in turn
inform KCSAN that polling behaviour is intended.
Signed-off-by: Rohan McLure <redacted>
---
arch/powerpc/platforms/powernv/opal-async.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/arch/powerpc/platforms/powernv/opal-async.c b/arch/powerpc/platforms/powernv/opal-async.c
index c094fdf5825c..282d2ac6fbb0 100644
--- a/arch/powerpc/platforms/powernv/opal-async.c
+++ b/arch/powerpc/platforms/powernv/opal-async.c@@ -146,7 +146,7 @@ int opal_async_wait_response(uint64_t token, struct opal_msg *msg) * functional. */ opal_wake_poller(); - wait_event(opal_async_wait, opal_async_tokens[token].state + wait_event(opal_async_wait, READ_ONCE(opal_async_tokens[token].state) == ASYNC_TOKEN_COMPLETED); memcpy(msg, &opal_async_tokens[token].response, sizeof(*msg));
@@ -185,7 +185,7 @@ int opal_async_wait_response_interruptible(uint64_t token, struct opal_msg *msg) * interruptible version before doing anything else with the * token. */ - if (opal_async_tokens[token].state == ASYNC_TOKEN_ALLOCATED) { + if (READ_ONCE(opal_async_tokens[token].state) == ASYNC_TOKEN_ALLOCATED) { spin_lock_irqsave(&opal_async_comp_lock, flags); if (opal_async_tokens[token].state == ASYNC_TOKEN_ALLOCATED) opal_async_tokens[token].state = ASYNC_TOKEN_DISPATCHED;
@@ -199,7 +199,7 @@ int opal_async_wait_response_interruptible(uint64_t token, struct opal_msg *msg) */ opal_wake_poller(); ret = wait_event_interruptible(opal_async_wait, - opal_async_tokens[token].state == + READ_ONCE(opal_async_tokens[token].state) == ASYNC_TOKEN_COMPLETED); if (!ret) memcpy(msg, &opal_async_tokens[token].response, sizeof(*msg));
--
2.37.2