[tip: x86/cleanups] x86/qspinlock-paravirt: Fix missing-prototype warning

tip-bot2 for Arnd Bergmann
2023-08-03T15:59:20Z

The following commit has been merged into the x86/cleanups branch of tip:

Commit-ID: 8874a414f8f706daf1de467cbf2550988ebec09d
Gitweb: https://git.kernel.org/tip/8874a414f8f706daf1de467cbf2550988ebec09d
Author: Arnd Bergmann <arnd@arndb.de>
AuthorDate: Thu, 03 Aug 2023 10:26:19 +02:00
Committer: Borislav Petkov (AMD) <bp@alien8.de>
CommitterDate: Thu, 03 Aug 2023 17:15:05 +02:00

x86/qspinlock-paravirt: Fix missing-prototype warning

__pv_queued_spin_unlock_slowpath() is defined in a header file as
a global function, and designed to be called from inline asm, but
there is no prototype visible in the definition:

kernel/locking/qspinlock_paravirt.h:493:1: error: no previous \
prototype for '__pv_queued_spin_unlock_slowpath' [-Werror=missing-prototypes]

Add this to the x86 header that contains the inline asm calling it,
and ensure this gets included before the definition, rather than
after it.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Link: https://lore.kernel.org/r/20230803082619.1369127-8-arnd@kernel.org
---
arch/x86/include/asm/qspinlock_paravirt.h | 2 ++
kernel/locking/qspinlock_paravirt.h | 20 ++++++++++----------
2 files changed, 12 insertions(+), 10 deletions(-)

diff --git a/arch/x86/include/asm/qspinlock_paravirt.h b/arch/x86/include/asm/qspinlock_paravirt.h
index 42b17cf..85b6e36 100644
--- a/arch/x86/include/asm/qspinlock_paravirt.h
+++ b/arch/x86/include/asm/qspinlock_paravirt.h
@@ -4,6 +4,8 @@

#include <asm/ibt.h>

+void __lockfunc __pv_queued_spin_unlock_slowpath(struct qspinlock *lock, u8 locked);
+
/*
* For x86-64, PV_CALLEE_SAVE_REGS_THUNK() saves and restores 8 64-bit
* registers. For i386, however, only 1 32-bit register needs to be saved
diff --git a/kernel/locking/qspinlock_paravirt.h b/kernel/locking/qspinlock_paravirt.h
index 6afc249..6a0184e 100644
--- a/kernel/locking/qspinlock_paravirt.h
+++ b/kernel/locking/qspinlock_paravirt.h
@@ -486,6 +486,16 @@ gotlock:
}

/*
+ * Include the architecture specific callee-save thunk of the
+ * __pv_queued_spin_unlock(). This thunk is put together with
+ * __pv_queued_spin_unlock() to make the callee-save thunk and the real unlock
+ * function close to each other sharing consecutive instruction cachelines.
+ * Alternatively, architecture specific version of __pv_queued_spin_unlock()
+ * can be defined.
+ */
+#include <asm/qspinlock_paravirt.h>
+
+/*
* PV versions of the unlock fastpath and slowpath functions to be used
* instead of queued_spin_unlock().
*/
@@ -533,16 +543,6 @@ __pv_queued_spin_unlock_slowpath(struct qspinlock *lock, u8 locked)
pv_kick(node->cpu);
}

-/*
- * Include the architecture specific callee-save thunk of the
- * __pv_queued_spin_unlock(). This thunk is put together with
- * __pv_queued_spin_unlock() to make the callee-save thunk and the real unlock
- * function close to each other sharing consecutive instruction cachelines.
- * Alternatively, architecture specific version of __pv_queued_spin_unlock()
- * can be defined.
- */
-#include <asm/qspinlock_paravirt.h>
-
#ifndef __pv_queued_spin_unlock
__visible __lockfunc void __pv_queued_spin_unlock(struct qspinlock *lock)
{