From 57424166118b0c763a62a2d629540f809f762dcf Mon Sep 17 00:00:00 2001 From: Taylor R Campbell Date: Sat, 5 Aug 2023 19:07:45 +0000 Subject: [PATCH] xen/x86: Get the right intrframe pointer in ddb ipi. This was broken with the transition from evtchn_set_handler to intr_establish_xname in 2017, remained broken with the transition from intr_establish_xname to xen_intr_establish_xname in 2018, and still remained broken when xen_intr_establish_xname was changed back to evtchn_set_handler in 2020. The mechanism is grody -- instead of a secret second argument to the interrupt handler, the intrframe pointer should be replaced by a struct cpu_info member that is saved and restored by the interrupt handler calling logic. But we should make sure the replacement actually works first -- which is not trivial in part because the users are hidden behind sketchy function pointer casts. With any luck, this will make `mach cpu N' work in ddb on Xen. --- sys/arch/xen/x86/xen_ipi.c | 10 ++++------ 1 file changed, 4 insertions(+), 6 deletions(-) diff --git a/sys/arch/xen/x86/xen_ipi.c b/sys/arch/xen/x86/xen_ipi.c index 7e5bf3fe7b02..20406b72c77a 100644 --- a/sys/arch/xen/x86/xen_ipi.c +++ b/sys/arch/xen/x86/xen_ipi.c @@ -90,18 +90,15 @@ static void (*xen_ipifunc[XEN_NIPIS])(struct cpu_info *, struct intrframe *) = }; static int -xen_ipi_handler(void *arg) +xen_ipi_handler(void *arg, struct intrframe *regs) { uint32_t pending; int bit; struct cpu_info *ci; - struct intrframe *regs; ci = curcpu(); - regs = arg; KASSERT(ci == arg); - pending = atomic_swap_32(&ci->ci_ipis, 0); KDASSERT((pending >> XEN_NIPIS) == 0); @@ -142,8 +139,9 @@ xen_ipi_init(void) snprintf(intr_xname, sizeof(intr_xname), "%s ipi", device_xname(ci->ci_dev)); - if (event_set_handler(evtchn, xen_ipi_handler, ci, IPL_HIGH, NULL, - intr_xname, true, ci) == NULL) { + if (event_set_handler(evtchn, + __FPTRCAST(int (*)(void *), xen_ipi_handler), ci, IPL_HIGH, + NULL, intr_xname, true, ci) == NULL) { panic("%s: unable to register ipi handler\n", __func__); /* NOTREACHED */ }