From: Arnd Bergmann <arnd@xxxxxxxx>
__pv_queued_spin_unlock_slowpath is defined in a header file as a global
function, and designed to be called from an 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.
The native_pv_lock_init function in turn is only declared in SMP
builds but can be left out in UP to avoid another warning:
arch/x86/kernel/paravirt.c:76:13: error: no previous prototype for 'native_pv_lock_init' [-Werror=missing-prototypes]
Signed-off-by: Arnd Bergmann <arnd@xxxxxxxx>
---
arch/x86/include/asm/qspinlock_paravirt.h | 2 ++
arch/x86/kernel/paravirt.c | 2 ++
kernel/locking/qspinlock_paravirt.h | 20 ++++++++++----------
3 files changed, 14 insertions(+), 10 deletions(-)
diff --git a/arch/x86/include/asm/qspinlock_paravirt.h b/arch/x86/include/asm/qspinlock_paravirt.h
index 42b17cf10b10..85b6e3609cb9 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/arch/x86/kernel/paravirt.c b/arch/x86/kernel/paravirt.c
index ac10b46c5832..eb67aa4cc5ef 100644
--- a/arch/x86/kernel/paravirt.c
+++ b/arch/x86/kernel/paravirt.c
@@ -73,11 +73,13 @@ DEFINE_PARAVIRT_ASM(pv_native_read_cr2, "mov %cr2, %rax", .noinstr.text);
DEFINE_STATIC_KEY_TRUE(virt_spin_lock_key);
+#ifdef CONFIG_SMP
void __init native_pv_lock_init(void)
{
if (!boot_cpu_has(X86_FEATURE_HYPERVISOR))
static_branch_disable(&virt_spin_lock_key);
}
+#endif
unsigned int paravirt_patch(u8 type, void *insn_buff, unsigned long addr,
unsigned int len)
diff --git a/kernel/locking/qspinlock_paravirt.h b/kernel/locking/qspinlock_paravirt.h
index 6afc249ce697..6a0184e9c234 100644
--- a/kernel/locking/qspinlock_paravirt.h
+++ b/kernel/locking/qspinlock_paravirt.h
@@ -485,6 +485,16 @@ pv_wait_head_or_lock(struct qspinlock *lock, struct mcs_spinlock *node)
return (u32)(atomic_read(&lock->val) | _Q_LOCKED_VAL);
}
+/*
+ * 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)
{
--
2.39.2
