Author: mav Date: Sat Jul 25 15:19:38 2020 New Revision: 363527 URL: https://svnweb.freebsd.org/changeset/base/363527
Log: Allow swi_sched() to be called from NMI context. For purposes of handling hardware error reported via NMIs I need a way to escape NMI context, being too restrictive to do something significant. To do it this change introduces new swi_sched() flag SWI_FROMNMI, making it careful about used KPIs. On platforms allowing IPI sending from NMI context (x86 for now) it immediately wakes clk_intr_event via new IPI_SWI, otherwise it works just like SWI_DELAY. To handle the delayed SWIs this patch calls clk_intr_event on every hardclock() tick. MFC after: 2 weeks Sponsored by: iXsystems, Inc. Differential Revision: https://reviews.freebsd.org/D25754 Modified: head/share/man/man9/swi.9 head/sys/amd64/amd64/apic_vector.S head/sys/amd64/amd64/mp_machdep.c head/sys/amd64/include/smp.h head/sys/i386/i386/apic_vector.s head/sys/i386/i386/mp_machdep.c head/sys/kern/kern_clock.c head/sys/kern/kern_intr.c head/sys/sys/interrupt.h head/sys/x86/include/apicvar.h head/sys/x86/include/x86_smp.h head/sys/x86/x86/mp_x86.c head/sys/x86/xen/xen_apic.c Modified: head/share/man/man9/swi.9 ============================================================================== --- head/share/man/man9/swi.9 Sat Jul 25 14:27:12 2020 (r363526) +++ head/share/man/man9/swi.9 Sat Jul 25 15:19:38 2020 (r363527) @@ -23,7 +23,7 @@ .\" .\" $FreeBSD$ .\" -.Dd April 19, 2012 +.Dd July 25, 2020 .Dt SWI 9 .Os .Sh NAME @@ -132,7 +132,7 @@ The .Fa flags argument specifies how and when the handler should be run and is a mask of one or more of the following flags: -.Bl -tag -width SWI_DELAY +.Bl -tag -width SWI_FROMNMI .It Dv SWI_DELAY Specifies that the kernel should mark the specified handler as needing to run, but the kernel should not schedule the software interrupt thread to run. @@ -146,6 +146,13 @@ functionality performed by .Fn setdelayed in earlier versions of .Fx . +.It Dv SWI_FROMNMI +Specifies that +.Fn swi_sched +is called from NMI context and should be careful about used KPIs. +On platforms allowing IPI sending from NMI context it immediately wakes +.Va clk_intr_event +via the IPI, otherwise it works just like SWI_DELAY. .El .Pp The Modified: head/sys/amd64/amd64/apic_vector.S ============================================================================== --- head/sys/amd64/amd64/apic_vector.S Sat Jul 25 14:27:12 2020 (r363526) +++ head/sys/amd64/amd64/apic_vector.S Sat Jul 25 15:19:38 2020 (r363527) @@ -206,6 +206,16 @@ IDTVEC(spuriousint) jmp doreti /* + * Executed by a CPU when it receives an IPI_SWI. + */ + INTR_HANDLER ipi_swi + call as_lapic_eoi + FAKE_MCOUNT(TF_RIP(%rsp)) + call ipi_swi_handler + MEXITCOUNT + jmp doreti + +/* * Executed by a CPU when it receives a RENDEZVOUS IPI from another CPU. * * - Calls the generic rendezvous action function. Modified: head/sys/amd64/amd64/mp_machdep.c ============================================================================== --- head/sys/amd64/amd64/mp_machdep.c Sat Jul 25 14:27:12 2020 (r363526) +++ head/sys/amd64/amd64/mp_machdep.c Sat Jul 25 15:19:38 2020 (r363527) @@ -223,6 +223,10 @@ cpu_mp_start(void) setidt(IPI_SUSPEND, pti ? IDTVEC(cpususpend_pti) : IDTVEC(cpususpend), SDT_SYSIGT, SEL_KPL, 0); + /* Install an IPI for calling delayed SWI */ + setidt(IPI_SWI, pti ? IDTVEC(ipi_swi_pti) : IDTVEC(ipi_swi), + SDT_SYSIGT, SEL_KPL, 0); + /* Set boot_cpu_id if needed. */ if (boot_cpu_id == -1) { boot_cpu_id = PCPU_GET(apic_id); Modified: head/sys/amd64/include/smp.h ============================================================================== --- head/sys/amd64/include/smp.h Sat Jul 25 14:27:12 2020 (r363526) +++ head/sys/amd64/include/smp.h Sat Jul 25 15:19:38 2020 (r363527) @@ -32,6 +32,7 @@ inthand_t IDTVEC(invlop_pti), IDTVEC(invlop), IDTVEC(ipi_intr_bitmap_handler_pti), + IDTVEC(ipi_swi_pti), IDTVEC(cpustop_pti), IDTVEC(cpususpend_pti), IDTVEC(rendezvous_pti); Modified: head/sys/i386/i386/apic_vector.s ============================================================================== --- head/sys/i386/i386/apic_vector.s Sat Jul 25 14:27:12 2020 (r363526) +++ head/sys/i386/i386/apic_vector.s Sat Jul 25 15:19:38 2020 (r363527) @@ -309,6 +309,23 @@ IDTVEC(cpususpend) jmp doreti /* + * Executed by a CPU when it receives an IPI_SWI. + */ + .text + SUPERALIGN_TEXT +IDTVEC(ipi_swi) + PUSH_FRAME + SET_KERNEL_SREGS + cld + KENTER + call as_lapic_eoi + FAKE_MCOUNT(TF_EIP(%esp)) + movl $ipi_swi_handler, %eax + call *%eax + MEXITCOUNT + jmp doreti + +/* * Executed by a CPU when it receives a RENDEZVOUS IPI from another CPU. * * - Calls the generic rendezvous action function. Modified: head/sys/i386/i386/mp_machdep.c ============================================================================== --- head/sys/i386/i386/mp_machdep.c Sat Jul 25 14:27:12 2020 (r363526) +++ head/sys/i386/i386/mp_machdep.c Sat Jul 25 15:19:38 2020 (r363527) @@ -188,6 +188,10 @@ cpu_mp_start(void) setidt(IPI_SUSPEND, IDTVEC(cpususpend), SDT_SYS386IGT, SEL_KPL, GSEL(GCODE_SEL, SEL_KPL)); + /* Install an IPI for calling delayed SWI */ + setidt(IPI_SWI, IDTVEC(ipi_swi), + SDT_SYS386IGT, SEL_KPL, GSEL(GCODE_SEL, SEL_KPL)); + /* Set boot_cpu_id if needed. */ if (boot_cpu_id == -1) { boot_cpu_id = PCPU_GET(apic_id); Modified: head/sys/kern/kern_clock.c ============================================================================== --- head/sys/kern/kern_clock.c Sat Jul 25 14:27:12 2020 (r363526) +++ head/sys/kern/kern_clock.c Sat Jul 25 15:19:38 2020 (r363527) @@ -508,6 +508,7 @@ hardclock(int cnt, int usermode) if (i > 0 && i <= newticks) watchdog_fire(); } + intr_event_handle(clk_intr_event, NULL); } if (curcpu == CPU_FIRST()) cpu_tick_calibration(); Modified: head/sys/kern/kern_intr.c ============================================================================== --- head/sys/kern/kern_intr.c Sat Jul 25 14:27:12 2020 (r363526) +++ head/sys/kern/kern_intr.c Sat Jul 25 15:19:38 2020 (r363527) @@ -60,6 +60,7 @@ __FBSDID("$FreeBSD$"); #include <machine/atomic.h> #include <machine/cpu.h> #include <machine/md_var.h> +#include <machine/smp.h> #include <machine/stdarg.h> #ifdef DDB #include <ddb/ddb.h> @@ -85,6 +86,7 @@ struct intr_entropy { uintptr_t event; }; +struct intr_event *clk_intr_event; struct intr_event *tty_intr_event; void *vm_ih; struct proc *intrproc; @@ -1018,7 +1020,7 @@ swi_add(struct intr_event **eventp, const char *name, void *arg, int pri, enum intr_type flags, void **cookiep) { struct intr_event *ie; - int error; + int error = 0; if (flags & INTR_ENTROPY) return (EINVAL); @@ -1036,8 +1038,10 @@ swi_add(struct intr_event **eventp, const char *name, if (eventp != NULL) *eventp = ie; } - error = intr_event_add_handler(ie, name, NULL, handler, arg, - PI_SWI(pri), flags, cookiep); + if (handler != NULL) { + error = intr_event_add_handler(ie, name, NULL, handler, arg, + PI_SWI(pri), flags, cookiep); + } return (error); } @@ -1055,9 +1059,11 @@ swi_sched(void *cookie, int flags) CTR3(KTR_INTR, "swi_sched: %s %s need=%d", ie->ie_name, ih->ih_name, ih->ih_need); - entropy.event = (uintptr_t)ih; - entropy.td = curthread; - random_harvest_queue(&entropy, sizeof(entropy), RANDOM_SWI); + if ((flags & SWI_FROMNMI) == 0) { + entropy.event = (uintptr_t)ih; + entropy.td = curthread; + random_harvest_queue(&entropy, sizeof(entropy), RANDOM_SWI); + } /* * Set ih_need for this handler so that if the ithread is already @@ -1066,7 +1072,16 @@ swi_sched(void *cookie, int flags) */ ih->ih_need = 1; - if (!(flags & SWI_DELAY)) { + if (flags & SWI_DELAY) + return; + + if (flags & SWI_FROMNMI) { +#if defined(SMP) && (defined(__i386__) || defined(__amd64__)) + KASSERT(ie == clk_intr_event, + ("SWI_FROMNMI used not with clk_intr_event")); + ipi_self_from_nmi(IPI_SWI); +#endif + } else { VM_CNT_INC(v_soft); error = intr_event_schedule_thread(ie); KASSERT(error == 0, ("stray software interrupt")); @@ -1346,6 +1361,8 @@ intr_event_handle(struct intr_event *ie, struct trapfr CK_SLIST_FOREACH(ih, &ie->ie_handlers, ih_next) { if ((ih->ih_flags & IH_SUSP) != 0) continue; + if ((ie->ie_flags & IE_SOFT) != 0 && ih->ih_need == 0) + continue; if (ih->ih_filter == NULL) { thread = true; continue; @@ -1570,6 +1587,9 @@ static void start_softintr(void *dummy) { + if (swi_add(&clk_intr_event, "clk", NULL, NULL, SWI_CLOCK, + INTR_MPSAFE, NULL)) + panic("died while creating clk swi ithread"); if (swi_add(NULL, "vm", swi_vm, NULL, SWI_VM, INTR_MPSAFE, &vm_ih)) panic("died while creating vm swi ithread"); } Modified: head/sys/sys/interrupt.h ============================================================================== --- head/sys/sys/interrupt.h Sat Jul 25 14:27:12 2020 (r363526) +++ head/sys/sys/interrupt.h Sat Jul 25 15:19:38 2020 (r363527) @@ -133,7 +133,8 @@ struct intr_event { #define IE_SOFT 0x000001 /* Software interrupt. */ #define IE_ADDING_THREAD 0x000004 /* Currently building an ithread. */ -/* Flags to pass to sched_swi. */ +/* Flags to pass to swi_sched. */ +#define SWI_FROMNMI 0x1 #define SWI_DELAY 0x2 /* @@ -151,6 +152,7 @@ struct intr_event { struct proc; +extern struct intr_event *clk_intr_event; extern struct intr_event *tty_intr_event; extern void *vm_ih; Modified: head/sys/x86/include/apicvar.h ============================================================================== --- head/sys/x86/include/apicvar.h Sat Jul 25 14:27:12 2020 (r363526) +++ head/sys/x86/include/apicvar.h Sat Jul 25 15:19:38 2020 (r363527) @@ -130,7 +130,8 @@ #define IPI_STOP (APIC_IPI_INTS + 6) /* Stop CPU until restarted. */ #define IPI_SUSPEND (APIC_IPI_INTS + 7) /* Suspend CPU until restarted. */ -#define IPI_DYN_FIRST (APIC_IPI_INTS + 8) +#define IPI_SWI (APIC_IPI_INTS + 8) /* Run clk_intr_event. */ +#define IPI_DYN_FIRST (APIC_IPI_INTS + 9) #define IPI_DYN_LAST (254) /* IPIs allocated at runtime */ /* Modified: head/sys/x86/include/x86_smp.h ============================================================================== --- head/sys/x86/include/x86_smp.h Sat Jul 25 14:27:12 2020 (r363526) +++ head/sys/x86/include/x86_smp.h Sat Jul 25 15:19:38 2020 (r363527) @@ -76,6 +76,7 @@ extern u_long *ipi_rendezvous_counts[MAXCPU]; /* IPI handlers */ inthand_t IDTVEC(ipi_intr_bitmap_handler), /* Bitmap based IPIs */ + IDTVEC(ipi_swi), /* Runs delayed SWI */ IDTVEC(cpustop), /* CPU stops & waits to be restarted */ IDTVEC(cpususpend), /* CPU suspends & waits to be resumed */ IDTVEC(rendezvous); /* handle CPU rendezvous */ @@ -96,6 +97,7 @@ void ipi_all_but_self(u_int ipi); void ipi_bitmap_handler(struct trapframe frame); void ipi_cpu(int cpu, u_int ipi); int ipi_nmi_handler(void); +void ipi_swi_handler(struct trapframe frame); void ipi_selected(cpuset_t cpus, u_int ipi); void ipi_self_from_nmi(u_int vector); void set_interrupt_apic_ids(void); Modified: head/sys/x86/x86/mp_x86.c ============================================================================== --- head/sys/x86/x86/mp_x86.c Sat Jul 25 14:27:12 2020 (r363526) +++ head/sys/x86/x86/mp_x86.c Sat Jul 25 15:19:38 2020 (r363527) @@ -47,6 +47,7 @@ __FBSDID("$FreeBSD$"); #ifdef GPROF #include <sys/gmon.h> #endif +#include <sys/interrupt.h> #include <sys/kdb.h> #include <sys/kernel.h> #include <sys/ktr.h> @@ -1618,6 +1619,16 @@ cpususpend_handler(void) CPU_CLR_ATOMIC(cpu, &resuming_cpus); CPU_CLR_ATOMIC(cpu, &suspended_cpus); CPU_CLR_ATOMIC(cpu, &toresume_cpus); +} + +/* + * Handle an IPI_SWI by waking delayed SWI thread. + */ +void +ipi_swi_handler(struct trapframe frame) +{ + + intr_event_handle(clk_intr_event, &frame); } /* Modified: head/sys/x86/xen/xen_apic.c ============================================================================== --- head/sys/x86/xen/xen_apic.c Sat Jul 25 14:27:12 2020 (r363526) +++ head/sys/x86/xen/xen_apic.c Sat Jul 25 15:19:38 2020 (r363527) @@ -76,6 +76,7 @@ static driver_filter_t xen_invlcache; static driver_filter_t xen_ipi_bitmap_handler; static driver_filter_t xen_cpustop_handler; static driver_filter_t xen_cpususpend_handler; +static driver_filter_t xen_ipi_swi_handler; #endif /*---------------------------------- Macros ----------------------------------*/ @@ -103,6 +104,7 @@ static struct xen_ipi_handler xen_ipis[] = [IPI_TO_IDX(IPI_BITMAP_VECTOR)] = { xen_ipi_bitmap_handler, "b" }, [IPI_TO_IDX(IPI_STOP)] = { xen_cpustop_handler, "st" }, [IPI_TO_IDX(IPI_SUSPEND)] = { xen_cpususpend_handler, "sp" }, + [IPI_TO_IDX(IPI_SWI)] = { xen_ipi_swi_handler, "sw" }, }; #endif @@ -519,6 +521,15 @@ xen_cpususpend_handler(void *arg) { cpususpend_handler(); + return (FILTER_HANDLED); +} + +static int +xen_ipi_swi_handler(void *arg) +{ + struct trapframe *frame = arg; + + ipi_swi_handler(*frame); return (FILTER_HANDLED); } _______________________________________________ [email protected] mailing list https://lists.freebsd.org/mailman/listinfo/svn-src-all To unsubscribe, send any mail to "[email protected]"
