diff options
author | attilio <attilio@FreeBSD.org> | 2009-08-13 17:09:45 +0000 |
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committer | attilio <attilio@FreeBSD.org> | 2009-08-13 17:09:45 +0000 |
commit | e85ca71aadcc42a3f7cc90e6cff96c28f1c54290 (patch) | |
tree | fa01b2cb8792e972d05922a5507e082efa4d4c1d /sys/i386 | |
parent | b1786d80d2f6e85141431d158b4cf3a47a2f71ec (diff) | |
download | FreeBSD-src-e85ca71aadcc42a3f7cc90e6cff96c28f1c54290.zip FreeBSD-src-e85ca71aadcc42a3f7cc90e6cff96c28f1c54290.tar.gz |
* Completely Remove the option STOP_NMI from the kernel. This option
has proven to have a good effect when entering KDB by using a NMI,
but it completely violates all the good rules about interrupts
disabled while holding a spinlock in other occasions. This can be the
cause of deadlocks on events where a normal IPI_STOP is expected.
* Adds an new IPI called IPI_STOP_HARD on all the supported architectures.
This IPI is responsible for sending a stop message among CPUs using a
privileged channel when disponible. In other cases it just does match a
normal IPI_STOP.
Right now the IPI_STOP_HARD functionality uses a NMI on ia32 and amd64
architectures, while on the other has a normal IPI_STOP effect. It is
responsibility of maintainers to eventually implement an hard stop
when necessary and possible.
* Use the new IPI facility in order to implement a new userend SMP kernel
function called stop_cpus_hard(). That is specular to stop_cpu() but
it does use the privileged channel for the stopping facility.
* Let KDB use the newly introduced function stop_cpus_hard() and leave
stop_cpus() for all the other cases
* Disable interrupts on CPU0 when starting the process of APs suspension.
* Style cleanup and comments adding
This patch should fix the reboot/shutdown deadlocks many users are
constantly reporting on mailing lists.
Please don't forget to update your config file with the STOP_NMI
option removal
Reviewed by: jhb
Tested by: pho, bz, rink
Approved by: re (kib)
Diffstat (limited to 'sys/i386')
-rw-r--r-- | sys/i386/conf/GENERIC | 1 | ||||
-rw-r--r-- | sys/i386/conf/NOTES | 1 | ||||
-rw-r--r-- | sys/i386/i386/local_apic.c | 13 | ||||
-rw-r--r-- | sys/i386/i386/mp_machdep.c | 99 | ||||
-rw-r--r-- | sys/i386/i386/trap.c | 2 | ||||
-rw-r--r-- | sys/i386/include/apicvar.h | 7 | ||||
-rw-r--r-- | sys/i386/include/smp.h | 6 | ||||
-rw-r--r-- | sys/i386/xen/mp_machdep.c | 2 |
8 files changed, 45 insertions, 86 deletions
diff --git a/sys/i386/conf/GENERIC b/sys/i386/conf/GENERIC index 02f5a36..ef958af 100644 --- a/sys/i386/conf/GENERIC +++ b/sys/i386/conf/GENERIC @@ -70,7 +70,6 @@ options P1003_1B_SEMAPHORES # POSIX-style semaphores options _KPOSIX_PRIORITY_SCHEDULING # POSIX P1003_1B real-time extensions options PRINTF_BUFR_SIZE=128 # Prevent printf output being interspersed. options KBD_INSTALL_CDEV # install a CDEV entry in /dev -options STOP_NMI # Stop CPUS using NMI instead of IPI options HWPMC_HOOKS # Necessary kernel hooks for hwpmc(4) options AUDIT # Security event auditing options MAC # TrustedBSD MAC Framework diff --git a/sys/i386/conf/NOTES b/sys/i386/conf/NOTES index f442e24..f772b25 100644 --- a/sys/i386/conf/NOTES +++ b/sys/i386/conf/NOTES @@ -49,7 +49,6 @@ options MP_WATCHDOG # Debugging options. # -options STOP_NMI # Stop CPUS using NMI instead of IPI options COUNT_XINVLTLB_HITS # Counters for TLB events options COUNT_IPIS # Per-CPU IPI interrupt counters diff --git a/sys/i386/i386/local_apic.c b/sys/i386/i386/local_apic.c index 6b350e2..2cc6a45 100644 --- a/sys/i386/i386/local_apic.c +++ b/sys/i386/i386/local_apic.c @@ -1248,8 +1248,17 @@ lapic_ipi_vectored(u_int vector, int dest) KASSERT((vector & ~APIC_VECTOR_MASK) == 0, ("%s: invalid vector %d", __func__, vector)); - icrlo = vector | APIC_DELMODE_FIXED | APIC_DESTMODE_PHY | - APIC_LEVEL_DEASSERT | APIC_TRIGMOD_EDGE; + icrlo = APIC_DESTMODE_PHY | APIC_TRIGMOD_EDGE; + + /* + * IPI_STOP_HARD is just a "fake" vector used to send a NMI. + * Use special rules regard NMI if passed, otherwise specify + * the vector. + */ + if (vector == IPI_STOP_HARD) + icrlo |= APIC_DELMODE_NMI | APIC_LEVEL_ASSERT; + else + icrlo |= vector | APIC_DELMODE_FIXED | APIC_LEVEL_DEASSERT; destfield = 0; switch (dest) { case APIC_IPI_DEST_SELF: diff --git a/sys/i386/i386/mp_machdep.c b/sys/i386/i386/mp_machdep.c index 0bfe91d..6729288 100644 --- a/sys/i386/i386/mp_machdep.c +++ b/sys/i386/i386/mp_machdep.c @@ -155,12 +155,6 @@ vm_offset_t smp_tlb_addr1; vm_offset_t smp_tlb_addr2; volatile int smp_tlb_wait; -#ifdef STOP_NMI -static volatile cpumask_t ipi_nmi_pending; - -static void ipi_nmi_selected(cpumask_t cpus); -#endif - #ifdef COUNT_IPIS /* Interrupt counts. */ static u_long *ipi_preempt_counts[MAXCPU]; @@ -177,21 +171,8 @@ u_long *ipi_lazypmap_counts[MAXCPU]; * Local data and functions. */ -#ifdef STOP_NMI -/* - * Provide an alternate method of stopping other CPUs. If another CPU has - * disabled interrupts the conventional STOP IPI will be blocked. This - * NMI-based stop should get through in that case. - */ -static int stop_cpus_with_nmi = 1; -SYSCTL_INT(_debug, OID_AUTO, stop_cpus_with_nmi, CTLTYPE_INT | CTLFLAG_RW, - &stop_cpus_with_nmi, 0, ""); -TUNABLE_INT("debug.stop_cpus_with_nmi", &stop_cpus_with_nmi); -#else -#define stop_cpus_with_nmi 0 -#endif - static u_int logical_cpus; +static volatile cpumask_t ipi_nmi_pending; /* used to hold the AP's until we are ready to release them */ static struct mtx ap_boot_mtx; @@ -1318,12 +1299,14 @@ ipi_selected(cpumask_t cpus, u_int ipi) ipi = IPI_BITMAP_VECTOR; } -#ifdef STOP_NMI - if (ipi == IPI_STOP && stop_cpus_with_nmi) { - ipi_nmi_selected(cpus); - return; - } -#endif + /* + * IPI_STOP_HARD maps to a NMI and the trap handler needs a bit + * of help in order to understand what is the source. + * Set the mask of receiving CPUs for this purpose. + */ + if (ipi == IPI_STOP_HARD) + atomic_set_int(&ipi_nmi_pending, cpus); + CTR3(KTR_SMP, "%s: cpus: %x ipi: %x", __func__, cpus, ipi); while ((cpu = ffs(cpus)) != 0) { cpu--; @@ -1354,64 +1337,42 @@ void ipi_all_but_self(u_int ipi) { - if (IPI_IS_BITMAPED(ipi) || (ipi == IPI_STOP && stop_cpus_with_nmi)) { + if (IPI_IS_BITMAPED(ipi)) { ipi_selected(PCPU_GET(other_cpus), ipi); return; } + + /* + * IPI_STOP_HARD maps to a NMI and the trap handler needs a bit + * of help in order to understand what is the source. + * Set the mask of receiving CPUs for this purpose. + */ + if (ipi == IPI_STOP_HARD) + atomic_set_int(&ipi_nmi_pending, PCPU_GET(other_cpus)); CTR2(KTR_SMP, "%s: ipi: %x", __func__, ipi); lapic_ipi_vectored(ipi, APIC_IPI_DEST_OTHERS); } -#ifdef STOP_NMI -/* - * send NMI IPI to selected CPUs - */ - -#define BEFORE_SPIN 1000000 - -void -ipi_nmi_selected(cpumask_t cpus) -{ - int cpu; - register_t icrlo; - - icrlo = APIC_DELMODE_NMI | APIC_DESTMODE_PHY | APIC_LEVEL_ASSERT - | APIC_TRIGMOD_EDGE; - - CTR2(KTR_SMP, "%s: cpus: %x nmi", __func__, cpus); - - atomic_set_int(&ipi_nmi_pending, cpus); - - while ((cpu = ffs(cpus)) != 0) { - cpu--; - cpus &= ~(1 << cpu); - - KASSERT(cpu_apic_ids[cpu] != -1, - ("IPI NMI to non-existent CPU %d", cpu)); - - /* Wait for an earlier IPI to finish. */ - if (!lapic_ipi_wait(BEFORE_SPIN)) - panic("ipi_nmi_selected: previous IPI has not cleared"); - - lapic_ipi_raw(icrlo, cpu_apic_ids[cpu]); - } -} - int -ipi_nmi_handler(void) +ipi_nmi_handler() { - int cpumask = PCPU_GET(cpumask); + cpumask_t cpumask; - if (!(ipi_nmi_pending & cpumask)) - return 1; + /* + * As long as there is not a simple way to know about a NMI's + * source, if the bitmask for the current CPU is present in + * the global pending bitword an IPI_STOP_HARD has been issued + * and should be handled. + */ + cpumask = PCPU_GET(cpumask); + if ((ipi_nmi_pending & cpumask) == 0) + return (1); atomic_clear_int(&ipi_nmi_pending, cpumask); cpustop_handler(); - return 0; + return (0); } -#endif /* STOP_NMI */ - /* * Handle an IPI_STOP by saving our current context and spinning until we * are resumed. diff --git a/sys/i386/i386/trap.c b/sys/i386/i386/trap.c index e967104..354d791 100644 --- a/sys/i386/i386/trap.c +++ b/sys/i386/i386/trap.c @@ -211,13 +211,11 @@ trap(struct trapframe *frame) type = frame->tf_trapno; #ifdef SMP -#ifdef STOP_NMI /* Handler for NMI IPIs used for stopping CPUs. */ if (type == T_NMI) { if (ipi_nmi_handler() == 0) goto out; } -#endif /* STOP_NMI */ #endif /* SMP */ #ifdef KDB diff --git a/sys/i386/include/apicvar.h b/sys/i386/include/apicvar.h index a03c083..a13766f 100644 --- a/sys/i386/include/apicvar.h +++ b/sys/i386/include/apicvar.h @@ -100,11 +100,6 @@ * smp_ipi_mtx and waits for the completion of the IPI (Only one IPI user * at a time) The second group uses a single interrupt and a bitmap to avoid * redundant IPI interrupts. - * - * Right now IPI_STOP used by kdb shares the interrupt priority class with - * the two IPI groups mentioned above. As such IPI_STOP may cause a deadlock. - * Eventually IPI_STOP should use NMI IPIs - this would eliminate this and - * other deadlocks caused by IPI_STOP. */ /* Interrupts for local APIC LVT entries other than the timer. */ @@ -134,6 +129,7 @@ #define IPI_IS_BITMAPED(x) ((x) <= IPI_BITMAP_LAST) #define IPI_STOP (APIC_IPI_INTS + 7) /* Stop CPU until restarted. */ +#define IPI_STOP_HARD (APIC_IPI_INTS + 8) /* Stop CPU with a NMI. */ #else /* XEN */ /* These are the normal i386 APIC definitions */ @@ -161,6 +157,7 @@ #define IPI_IS_BITMAPED(x) ((x) <= IPI_BITMAP_LAST) #define IPI_STOP (APIC_IPI_INTS + 7) /* Stop CPU until restarted. */ +#define IPI_STOP_HARD (APIC_IPI_INTS + 8) /* Stop CPU with a NMI. */ #endif /* XEN */ /* diff --git a/sys/i386/include/smp.h b/sys/i386/include/smp.h index 917c285..968cdb4 100644 --- a/sys/i386/include/smp.h +++ b/sys/i386/include/smp.h @@ -60,7 +60,8 @@ inthand_t void cpu_add(u_int apic_id, char boot_cpu); void cpustop_handler(void); void init_secondary(void); -void ipi_selected(u_int cpus, u_int ipi); +int ipi_nmi_handler(void); +void ipi_selected(cpumask_t cpus, u_int ipi); void ipi_all_but_self(u_int ipi); #ifndef XEN void ipi_bitmap_handler(struct trapframe frame); @@ -76,9 +77,6 @@ void smp_masked_invlpg_range(cpumask_t mask, vm_offset_t startva, void smp_invltlb(void); void smp_masked_invltlb(cpumask_t mask); -#ifdef STOP_NMI -int ipi_nmi_handler(void); -#endif #ifdef XEN void ipi_to_irq_init(void); diff --git a/sys/i386/xen/mp_machdep.c b/sys/i386/xen/mp_machdep.c index 3aa03ce..bae07d4 100644 --- a/sys/i386/xen/mp_machdep.c +++ b/sys/i386/xen/mp_machdep.c @@ -90,8 +90,6 @@ __FBSDID("$FreeBSD$"); #include <xen/hypervisor.h> #include <xen/interface/vcpu.h> -#define stop_cpus_with_nmi 0 - int mp_naps; /* # of Applications processors */ int boot_cpu_id = -1; /* designated BSP */ |