Commit-ID: b987ffc18fb3b3b76b059aa9e372dbee26f7c4f2
Gitweb: https://git.kernel.org/tip/b987ffc18fb3b3b76b059aa9e372dbee26f7c4f2
Author: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
AuthorDate: Fri, 2 Nov 2018 14:26:53 +0100
Committer: Ingo Molnar <mingo@xxxxxxxxxx>
CommitDate: Sun, 4 Nov 2018 00:54:34 +0100
x86/qspinlock: Fix compile error
With a compiler that has asm-goto but not asm-cc-output and
CONFIG_PROFILE_ALL_BRANCHES=y we get a compiler error:
arch/x86/include/asm/rmwcc.h:23:17: error: jump into statement expression
Fix this by writing the if() as a boolean multiplication instead.
Reported-by: kbuild test robot <lkp@xxxxxxxxx>
Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: Will Deacon <will.deacon@xxxxxxx>
Cc: linux-kernel@xxxxxxxxxxxxxxx
Fixes: 7aa54be29765 ("locking/qspinlock, x86: Provide liveness guarantee")
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
---
arch/x86/include/asm/qspinlock.h | 13 ++++++++-----
1 file changed, 8 insertions(+), 5 deletions(-)
diff --git a/arch/x86/include/asm/qspinlock.h b/arch/x86/include/asm/qspinlock.h
index 87623c6b13db..bd5ac6cc37db 100644
--- a/arch/x86/include/asm/qspinlock.h
+++ b/arch/x86/include/asm/qspinlock.h
@@ -13,12 +13,15 @@
#define queued_fetch_set_pending_acquire queued_fetch_set_pending_acquire
static __always_inline u32 queued_fetch_set_pending_acquire(struct qspinlock *lock)
{
- u32 val = 0;
-
- if (GEN_BINARY_RMWcc(LOCK_PREFIX "btsl", lock->val.counter, c,
- "I", _Q_PENDING_OFFSET))
- val |= _Q_PENDING_VAL;
+ u32 val;
+ /*
+ * We can't use GEN_BINARY_RMWcc() inside an if() stmt because asm goto
+ * and CONFIG_PROFILE_ALL_BRANCHES=y results in a label inside a
+ * statement expression, which GCC doesn't like.
+ */
+ val = GEN_BINARY_RMWcc(LOCK_PREFIX "btsl", lock->val.counter, c,
+ "I", _Q_PENDING_OFFSET) * _Q_PENDING_VAL;
val |= atomic_read(&lock->val) & ~_Q_PENDING_MASK;
return val;
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