syscall_enter_from_user_mode_randomize_stack() replaces
syscall_enter_from_user_mode() and the subsequent invocation of
add_random_kstack_offset().

The advantage is that it applies the stack randomization right after
enter_from_user_mode() and thereby avoids the overhead of get/put_cpu_var()
as that code is invoked with interrupts disabled.

No functional change.

Signed-off-by: Thomas Gleixner <tglx@kernel.org>
Cc: Paul Walmsley <pjw@kernel.org>
Cc: Palmer Dabbelt <palmer@dabbelt.com>
Cc: linux-riscv@lists.infradead.org
---
 arch/riscv/kernel/traps.c |    5 +----
 1 file changed, 1 insertion(+), 4 deletions(-)

--- a/arch/riscv/kernel/traps.c
+++ b/arch/riscv/kernel/traps.c

@@ -7,7 +7,6 @@
 #include <linux/kernel.h>
 #include <linux/init.h>
 #include <linux/irqflags.h>
-#include <linux/randomize_kstack.h>
 #include <linux/sched.h>
 #include <linux/sched/debug.h>
 #include <linux/sched/signal.h>

@@ -333,9 +332,7 @@ void do_trap_ecall_u(struct pt_regs *reg

                riscv_v_vstate_discard(regs);

-               syscall = syscall_enter_from_user_mode(regs, syscall);
-
-               add_random_kstack_offset();
+               syscall = syscall_enter_from_user_mode_randomize_stack(regs, syscall);