x86/entry: Use run_sysvec_on_irqstack_cond() for XEN upcall

To avoid yet another macro implementation reuse the existing
run_sysvec_on_irqstack_cond() and move the set_irq_regs() handling into the
called function. Makes the code even simpler.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/20210210002512.869753106@linutronix.de

diff --git a/arch/x86/entry/common.c b/arch/x86/entry/common.c
index c4efffbe24dac2dcc19d62eb1d728df0b395fb14..60a5fc4da4757e54eaf6f4df713aac17a0b29670 100644 (file)
--- a/arch/x86/entry/common.c
+++ b/arch/x86/entry/common.c
@@ -245,30 +245,23 @@ static __always_inline bool get_and_clear_inhcall(void) { return false; }
 static __always_inline void restore_inhcall(bool inhcall) { }
 #endif
 
-static void __xen_pv_evtchn_do_upcall(void)
+static void __xen_pv_evtchn_do_upcall(struct pt_regs *regs)
 {
-       irq_enter_rcu();
+       struct pt_regs *old_regs = set_irq_regs(regs);
+
        inc_irq_stat(irq_hv_callback_count);
 
        xen_hvm_evtchn_do_upcall();
 
-       irq_exit_rcu();
+       set_irq_regs(old_regs);
 }
 
 __visible noinstr void xen_pv_evtchn_do_upcall(struct pt_regs *regs)
 {
-       struct pt_regs *old_regs;
+       irqentry_state_t state = irqentry_enter(regs);
        bool inhcall;
-       irqentry_state_t state;
 
-       state = irqentry_enter(regs);
-       old_regs = set_irq_regs(regs);
-
-       instrumentation_begin();
-       run_on_irqstack_cond(__xen_pv_evtchn_do_upcall, regs);
-       instrumentation_end();
-
-       set_irq_regs(old_regs);
+       run_sysvec_on_irqstack_cond(__xen_pv_evtchn_do_upcall, regs);
 
        inhcall = get_and_clear_inhcall();
        if (inhcall && !WARN_ON_ONCE(state.exit_rcu)) {