[PATCH] arm64: Skip apply SSBS call for non SSBS system

From: Gaurav Kohli
Date: Tue Aug 04 2020 - 10:15:13 EST

In a system where no cpu's implement SSBS, for
them no need to set pstate. This might help to save
few cpu cycles during context switch.

Signed-off-by: Gaurav Kohli <gkohli@xxxxxxxxxxxxxx>

diff --git a/arch/arm64/kernel/process.c b/arch/arm64/kernel/process.c
index 6089638..79f80f1 100644
--- a/arch/arm64/kernel/process.c
+++ b/arch/arm64/kernel/process.c
@@ -477,6 +477,13 @@ static void ssbs_thread_switch(struct task_struct *next)
struct pt_regs *regs = task_pt_regs(next);

+ * For Targets which don't have SSBS support, they
+ * can return from here.
+ */
+ return;
+ /*
* Nothing to do for kernel threads, but 'regs' may be junk
* (e.g. idle task) so check the flags and bail early.
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