[patch V2 08/13] x86/entry: Use run_sysvec_on_irqstack_cond() for XEN upcall

From: Thomas Gleixner
Date: Tue Feb 09 2021 - 21:11:53 EST


From: Thomas Gleixner <tglx@xxxxxxxxxxxxx>

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@xxxxxxxxxxxxx>
Reviewed-by: Kees Cook <keescook@xxxxxxxxxxxx>

---
arch/x86/entry/common.c | 19 ++++++-------------
1 file changed, 6 insertions(+), 13 deletions(-)

--- a/arch/x86/entry/common.c
+++ b/arch/x86/entry/common.c
@@ -249,30 +249,23 @@ static __always_inline bool get_and_clea
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)) {