diff options
author | Arjan van de Ven <arjan@linux.intel.com> | 2008-10-17 09:20:26 -0700 |
---|---|---|
committer | Arjan van de Ven <arjan@linux.intel.com> | 2008-10-17 09:20:26 -0700 |
commit | 651dab4264e4ba0e563f5ff56f748127246e9065 (patch) | |
tree | 016630974bdcb00fe529b673f96d389e0fd6dc94 /arch/mips/kernel/smtc.c | |
parent | 40b8606253552109815786e5d4b0de98782d31f5 (diff) | |
parent | 2e532d68a2b3e2aa6b19731501222069735c741c (diff) |
Merge commit 'linus/master' into merge-linus
Conflicts:
arch/x86/kvm/i8254.c
Diffstat (limited to 'arch/mips/kernel/smtc.c')
-rw-r--r-- | arch/mips/kernel/smtc.c | 260 |
1 files changed, 137 insertions, 123 deletions
diff --git a/arch/mips/kernel/smtc.c b/arch/mips/kernel/smtc.c index a516286532a..897fb2b4751 100644 --- a/arch/mips/kernel/smtc.c +++ b/arch/mips/kernel/smtc.c @@ -1,4 +1,21 @@ -/* Copyright (C) 2004 Mips Technologies, Inc */ +/* + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License + * as published by the Free Software Foundation; either version 2 + * of the License, or (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software + * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. + * + * Copyright (C) 2004 Mips Technologies, Inc + * Copyright (C) 2008 Kevin D. Kissell + */ #include <linux/clockchips.h> #include <linux/kernel.h> @@ -21,7 +38,6 @@ #include <asm/time.h> #include <asm/addrspace.h> #include <asm/smtc.h> -#include <asm/smtc_ipi.h> #include <asm/smtc_proc.h> /* @@ -58,11 +74,6 @@ unsigned long irq_hwmask[NR_IRQS]; asiduse smtc_live_asid[MAX_SMTC_TLBS][MAX_SMTC_ASIDS]; -/* - * Clock interrupt "latch" buffers, per "CPU" - */ - -static atomic_t ipi_timer_latch[NR_CPUS]; /* * Number of InterProcessor Interrupt (IPI) message buffers to allocate @@ -70,7 +81,7 @@ static atomic_t ipi_timer_latch[NR_CPUS]; #define IPIBUF_PER_CPU 4 -static struct smtc_ipi_q IPIQ[NR_CPUS]; +struct smtc_ipi_q IPIQ[NR_CPUS]; static struct smtc_ipi_q freeIPIq; @@ -282,7 +293,7 @@ static void smtc_configure_tlb(void) * phys_cpu_present_map and the logical/physical mappings. */ -int __init mipsmt_build_cpu_map(int start_cpu_slot) +int __init smtc_build_cpu_map(int start_cpu_slot) { int i, ntcs; @@ -325,7 +336,12 @@ static void smtc_tc_setup(int vpe, int tc, int cpu) write_tc_c0_tcstatus((read_tc_c0_tcstatus() & ~(TCSTATUS_TKSU | TCSTATUS_DA | TCSTATUS_IXMT)) | TCSTATUS_A); - write_tc_c0_tccontext(0); + /* + * TCContext gets an offset from the base of the IPIQ array + * to be used in low-level code to detect the presence of + * an active IPI queue + */ + write_tc_c0_tccontext((sizeof(struct smtc_ipi_q) * cpu) << 16); /* Bind tc to vpe */ write_tc_c0_tcbind(vpe); /* In general, all TCs should have the same cpu_data indications */ @@ -336,10 +352,18 @@ static void smtc_tc_setup(int vpe, int tc, int cpu) cpu_data[cpu].options &= ~MIPS_CPU_FPU; cpu_data[cpu].vpe_id = vpe; cpu_data[cpu].tc_id = tc; + /* Multi-core SMTC hasn't been tested, but be prepared */ + cpu_data[cpu].core = (read_vpe_c0_ebase() >> 1) & 0xff; } +/* + * Tweak to get Count registes in as close a sync as possible. + * Value seems good for 34K-class cores. + */ + +#define CP0_SKEW 8 -void mipsmt_prepare_cpus(void) +void smtc_prepare_cpus(int cpus) { int i, vpe, tc, ntc, nvpe, tcpervpe[NR_CPUS], slop, cpu; unsigned long flags; @@ -363,13 +387,13 @@ void mipsmt_prepare_cpus(void) IPIQ[i].head = IPIQ[i].tail = NULL; spin_lock_init(&IPIQ[i].lock); IPIQ[i].depth = 0; - atomic_set(&ipi_timer_latch[i], 0); } /* cpu_data index starts at zero */ cpu = 0; cpu_data[cpu].vpe_id = 0; cpu_data[cpu].tc_id = 0; + cpu_data[cpu].core = (read_c0_ebase() >> 1) & 0xff; cpu++; /* Report on boot-time options */ @@ -484,7 +508,8 @@ void mipsmt_prepare_cpus(void) write_vpe_c0_compare(0); /* Propagate Config7 */ write_vpe_c0_config7(read_c0_config7()); - write_vpe_c0_count(read_c0_count()); + write_vpe_c0_count(read_c0_count() + CP0_SKEW); + ehb(); } /* enable multi-threading within VPE */ write_vpe_c0_vpecontrol(read_vpe_c0_vpecontrol() | VPECONTROL_TE); @@ -556,7 +581,7 @@ void mipsmt_prepare_cpus(void) void __cpuinit smtc_boot_secondary(int cpu, struct task_struct *idle) { extern u32 kernelsp[NR_CPUS]; - long flags; + unsigned long flags; int mtflags; LOCK_MT_PRA(); @@ -585,24 +610,22 @@ void __cpuinit smtc_boot_secondary(int cpu, struct task_struct *idle) void smtc_init_secondary(void) { - /* - * Start timer on secondary VPEs if necessary. - * plat_timer_setup has already have been invoked by init/main - * on "boot" TC. Like per_cpu_trap_init() hack, this assumes that - * SMTC init code assigns TCs consdecutively and in ascending order - * to across available VPEs. - */ - if (((read_c0_tcbind() & TCBIND_CURTC) != 0) && - ((read_c0_tcbind() & TCBIND_CURVPE) - != cpu_data[smp_processor_id() - 1].vpe_id)){ - write_c0_compare(read_c0_count() + mips_hpt_frequency/HZ); - } - local_irq_enable(); } void smtc_smp_finish(void) { + int cpu = smp_processor_id(); + + /* + * Lowest-numbered CPU per VPE starts a clock tick. + * Like per_cpu_trap_init() hack, this assumes that + * SMTC init code assigns TCs consdecutively and + * in ascending order across available VPEs. + */ + if (cpu > 0 && (cpu_data[cpu].vpe_id != cpu_data[cpu - 1].vpe_id)) + write_c0_compare(read_c0_count() + mips_hpt_frequency/HZ); + printk("TC %d going on-line as CPU %d\n", cpu_data[smp_processor_id()].tc_id, smp_processor_id()); } @@ -753,8 +776,10 @@ void smtc_send_ipi(int cpu, int type, unsigned int action) { int tcstatus; struct smtc_ipi *pipi; - long flags; + unsigned long flags; int mtflags; + unsigned long tcrestart; + extern void r4k_wait_irqoff(void), __pastwait(void); if (cpu == smp_processor_id()) { printk("Cannot Send IPI to self!\n"); @@ -771,8 +796,6 @@ void smtc_send_ipi(int cpu, int type, unsigned int action) pipi->arg = (void *)action; pipi->dest = cpu; if (cpu_data[cpu].vpe_id != cpu_data[smp_processor_id()].vpe_id) { - if (type == SMTC_CLOCK_TICK) - atomic_inc(&ipi_timer_latch[cpu]); /* If not on same VPE, enqueue and send cross-VPE interrupt */ smtc_ipi_nq(&IPIQ[cpu], pipi); LOCK_CORE_PRA(); @@ -800,22 +823,29 @@ void smtc_send_ipi(int cpu, int type, unsigned int action) if ((tcstatus & TCSTATUS_IXMT) != 0) { /* - * Spin-waiting here can deadlock, - * so we queue the message for the target TC. + * If we're in the the irq-off version of the wait + * loop, we need to force exit from the wait and + * do a direct post of the IPI. + */ + if (cpu_wait == r4k_wait_irqoff) { + tcrestart = read_tc_c0_tcrestart(); + if (tcrestart >= (unsigned long)r4k_wait_irqoff + && tcrestart < (unsigned long)__pastwait) { + write_tc_c0_tcrestart(__pastwait); + tcstatus &= ~TCSTATUS_IXMT; + write_tc_c0_tcstatus(tcstatus); + goto postdirect; + } + } + /* + * Otherwise we queue the message for the target TC + * to pick up when he does a local_irq_restore() */ write_tc_c0_tchalt(0); UNLOCK_CORE_PRA(); - /* Try to reduce redundant timer interrupt messages */ - if (type == SMTC_CLOCK_TICK) { - if (atomic_postincrement(&ipi_timer_latch[cpu])!=0){ - smtc_ipi_nq(&freeIPIq, pipi); - return; - } - } smtc_ipi_nq(&IPIQ[cpu], pipi); } else { - if (type == SMTC_CLOCK_TICK) - atomic_inc(&ipi_timer_latch[cpu]); +postdirect: post_direct_ipi(cpu, pipi); write_tc_c0_tchalt(0); UNLOCK_CORE_PRA(); @@ -883,7 +913,7 @@ static void ipi_call_interrupt(void) smp_call_function_interrupt(); } -DECLARE_PER_CPU(struct clock_event_device, smtc_dummy_clockevent_device); +DECLARE_PER_CPU(struct clock_event_device, mips_clockevent_device); void ipi_decode(struct smtc_ipi *pipi) { @@ -891,20 +921,13 @@ void ipi_decode(struct smtc_ipi *pipi) struct clock_event_device *cd; void *arg_copy = pipi->arg; int type_copy = pipi->type; - int ticks; - smtc_ipi_nq(&freeIPIq, pipi); switch (type_copy) { case SMTC_CLOCK_TICK: irq_enter(); kstat_this_cpu.irqs[MIPS_CPU_IRQ_BASE + 1]++; - cd = &per_cpu(smtc_dummy_clockevent_device, cpu); - ticks = atomic_read(&ipi_timer_latch[cpu]); - atomic_sub(ticks, &ipi_timer_latch[cpu]); - while (ticks) { - cd->event_handler(cd); - ticks--; - } + cd = &per_cpu(mips_clockevent_device, cpu); + cd->event_handler(cd); irq_exit(); break; @@ -937,24 +960,48 @@ void ipi_decode(struct smtc_ipi *pipi) } } +/* + * Similar to smtc_ipi_replay(), but invoked from context restore, + * so it reuses the current exception frame rather than set up a + * new one with self_ipi. + */ + void deferred_smtc_ipi(void) { - struct smtc_ipi *pipi; - unsigned long flags; -/* DEBUG */ - int q = smp_processor_id(); + int cpu = smp_processor_id(); /* * Test is not atomic, but much faster than a dequeue, * and the vast majority of invocations will have a null queue. + * If irq_disabled when this was called, then any IPIs queued + * after we test last will be taken on the next irq_enable/restore. + * If interrupts were enabled, then any IPIs added after the + * last test will be taken directly. */ - if (IPIQ[q].head != NULL) { - while((pipi = smtc_ipi_dq(&IPIQ[q])) != NULL) { - /* ipi_decode() should be called with interrupts off */ - local_irq_save(flags); + + while (IPIQ[cpu].head != NULL) { + struct smtc_ipi_q *q = &IPIQ[cpu]; + struct smtc_ipi *pipi; + unsigned long flags; + + /* + * It may be possible we'll come in with interrupts + * already enabled. + */ + local_irq_save(flags); + + spin_lock(&q->lock); + pipi = __smtc_ipi_dq(q); + spin_unlock(&q->lock); + if (pipi != NULL) ipi_decode(pipi); - local_irq_restore(flags); - } + /* + * The use of the __raw_local restore isn't + * as obviously necessary here as in smtc_ipi_replay(), + * but it's more efficient, given that we're already + * running down the IPI queue. + */ + __raw_local_irq_restore(flags); } } @@ -975,7 +1022,7 @@ static irqreturn_t ipi_interrupt(int irq, void *dev_idm) struct smtc_ipi *pipi; unsigned long tcstatus; int sent; - long flags; + unsigned long flags; unsigned int mtflags; unsigned int vpflags; @@ -1066,55 +1113,53 @@ static void setup_cross_vpe_interrupts(unsigned int nvpe) /* * SMTC-specific hacks invoked from elsewhere in the kernel. - * - * smtc_ipi_replay is called from raw_local_irq_restore which is only ever - * called with interrupts disabled. We do rely on interrupts being disabled - * here because using spin_lock_irqsave()/spin_unlock_irqrestore() would - * result in a recursive call to raw_local_irq_restore(). */ -static void __smtc_ipi_replay(void) + /* + * smtc_ipi_replay is called from raw_local_irq_restore + */ + +void smtc_ipi_replay(void) { unsigned int cpu = smp_processor_id(); /* * To the extent that we've ever turned interrupts off, * we may have accumulated deferred IPIs. This is subtle. - * If we use the smtc_ipi_qdepth() macro, we'll get an - * exact number - but we'll also disable interrupts - * and create a window of failure where a new IPI gets - * queued after we test the depth but before we re-enable - * interrupts. So long as IXMT never gets set, however, * we should be OK: If we pick up something and dispatch * it here, that's great. If we see nothing, but concurrent * with this operation, another TC sends us an IPI, IXMT * is clear, and we'll handle it as a real pseudo-interrupt - * and not a pseudo-pseudo interrupt. + * and not a pseudo-pseudo interrupt. The important thing + * is to do the last check for queued message *after* the + * re-enabling of interrupts. */ - if (IPIQ[cpu].depth > 0) { - while (1) { - struct smtc_ipi_q *q = &IPIQ[cpu]; - struct smtc_ipi *pipi; - extern void self_ipi(struct smtc_ipi *); - - spin_lock(&q->lock); - pipi = __smtc_ipi_dq(q); - spin_unlock(&q->lock); - if (!pipi) - break; + while (IPIQ[cpu].head != NULL) { + struct smtc_ipi_q *q = &IPIQ[cpu]; + struct smtc_ipi *pipi; + unsigned long flags; + + /* + * It's just possible we'll come in with interrupts + * already enabled. + */ + local_irq_save(flags); + + spin_lock(&q->lock); + pipi = __smtc_ipi_dq(q); + spin_unlock(&q->lock); + /* + ** But use a raw restore here to avoid recursion. + */ + __raw_local_irq_restore(flags); + if (pipi) { self_ipi(pipi); smtc_cpu_stats[cpu].selfipis++; } } } -void smtc_ipi_replay(void) -{ - raw_local_irq_disable(); - __smtc_ipi_replay(); -} - EXPORT_SYMBOL(smtc_ipi_replay); void smtc_idle_loop_hook(void) @@ -1193,40 +1238,13 @@ void smtc_idle_loop_hook(void) } } - /* - * Now that we limit outstanding timer IPIs, check for hung TC - */ - for (tc = 0; tc < NR_CPUS; tc++) { - /* Don't check ourself - we'll dequeue IPIs just below */ - if ((tc != smp_processor_id()) && - atomic_read(&ipi_timer_latch[tc]) > timerq_limit) { - if (clock_hang_reported[tc] == 0) { - pdb_msg += sprintf(pdb_msg, - "TC %d looks hung with timer latch at %d\n", - tc, atomic_read(&ipi_timer_latch[tc])); - clock_hang_reported[tc]++; - } - } - } emt(mtflags); local_irq_restore(flags); if (pdb_msg != &id_ho_db_msg[0]) printk("CPU%d: %s", smp_processor_id(), id_ho_db_msg); #endif /* CONFIG_SMTC_IDLE_HOOK_DEBUG */ - /* - * Replay any accumulated deferred IPIs. If "Instant Replay" - * is in use, there should never be any. - */ -#ifndef CONFIG_MIPS_MT_SMTC_INSTANT_REPLAY - { - unsigned long flags; - - local_irq_save(flags); - __smtc_ipi_replay(); - local_irq_restore(flags); - } -#endif /* CONFIG_MIPS_MT_SMTC_INSTANT_REPLAY */ + smtc_ipi_replay(); } void smtc_soft_dump(void) @@ -1242,10 +1260,6 @@ void smtc_soft_dump(void) printk("%d: %ld\n", i, smtc_cpu_stats[i].selfipis); } smtc_ipi_qdump(); - printk("Timer IPI Backlogs:\n"); - for (i=0; i < NR_CPUS; i++) { - printk("%d: %d\n", i, atomic_read(&ipi_timer_latch[i])); - } printk("%d Recoveries of \"stolen\" FPU\n", atomic_read(&smtc_fpu_recoveries)); } |