[PATCH AUTOSEL 4.14 120/127] x86/speculation/mds: Mark mds_user_clear_cpu_buffers() __always_inline

Sasha Levin
2020-09-18T02:14:48Z

From: Thomas Gleixner <tglx@linutronix.de>

[ Upstream commit a7ef9ba986b5fae9d80f8a7b31db0423687efe4e ]

Prevent the compiler from uninlining and creating traceable/probable
functions as this is invoked _after_ context tracking switched to
CONTEXT_USER and rcu idle.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Alexandre Chartre <alexandre.chartre@oracle.com>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20200505134340.902709267@linutronix.de
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
arch/x86/include/asm/nospec-branch.h | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/arch/x86/include/asm/nospec-branch.h b/arch/x86/include/asm/nospec-branch.h
index 041d2a04be1d8..270448b178a7a 100644
--- a/arch/x86/include/asm/nospec-branch.h
+++ b/arch/x86/include/asm/nospec-branch.h
@@ -330,7 +330,7 @@ DECLARE_STATIC_KEY_FALSE(mds_idle_clear);
* combination with microcode which triggers a CPU buffer flush when the
* instruction is executed.
*/
-static inline void mds_clear_cpu_buffers(void)
+static __always_inline void mds_clear_cpu_buffers(void)
{
static const u16 ds = __KERNEL_DS;

@@ -351,7 +351,7 @@ static inline void mds_clear_cpu_buffers(void)
*
* Clear CPU buffers if the corresponding static key is enabled
*/
-static inline void mds_user_clear_cpu_buffers(void)
+static __always_inline void mds_user_clear_cpu_buffers(void)
{
if (static_branch_likely(&mds_user_clear))
mds_clear_cpu_buffers();
--
2.25.1