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Diffstat (limited to 'arch/mips/kernel/smtc.c')
| -rw-r--r-- | arch/mips/kernel/smtc.c | 1322 |
1 files changed, 1322 insertions, 0 deletions
diff --git a/arch/mips/kernel/smtc.c b/arch/mips/kernel/smtc.c new file mode 100644 index 00000000000..2e8e52c135e --- /dev/null +++ b/arch/mips/kernel/smtc.c @@ -0,0 +1,1322 @@ +/* Copyright (C) 2004 Mips Technologies, Inc */ + +#include <linux/kernel.h> +#include <linux/sched.h> +#include <linux/cpumask.h> +#include <linux/interrupt.h> + +#include <asm/cpu.h> +#include <asm/processor.h> +#include <asm/atomic.h> +#include <asm/system.h> +#include <asm/hardirq.h> +#include <asm/hazards.h> +#include <asm/mmu_context.h> +#include <asm/smp.h> +#include <asm/mipsregs.h> +#include <asm/cacheflush.h> +#include <asm/time.h> +#include <asm/addrspace.h> +#include <asm/smtc.h> +#include <asm/smtc_ipi.h> +#include <asm/smtc_proc.h> + +/* + * This file should be built into the kernel only if CONFIG_MIPS_MT_SMTC is set. + */ + +/* + * MIPSCPU_INT_BASE is identically defined in both + * asm-mips/mips-boards/maltaint.h and asm-mips/mips-boards/simint.h, + * but as yet there's no properly organized include structure that + * will ensure that the right *int.h file will be included for a + * given platform build. + */ + +#define MIPSCPU_INT_BASE 16 + +#define MIPS_CPU_IPI_IRQ 1 + +#define LOCK_MT_PRA() \ + local_irq_save(flags); \ + mtflags = dmt() + +#define UNLOCK_MT_PRA() \ + emt(mtflags); \ + local_irq_restore(flags) + +#define LOCK_CORE_PRA() \ + local_irq_save(flags); \ + mtflags = dvpe() + +#define UNLOCK_CORE_PRA() \ + evpe(mtflags); \ + local_irq_restore(flags) + +/* + * Data structures purely associated with SMTC parallelism + */ + + +/* + * Table for tracking ASIDs whose lifetime is prolonged. + */ + +asiduse smtc_live_asid[MAX_SMTC_TLBS][MAX_SMTC_ASIDS]; + +/* + * Clock interrupt "latch" buffers, per "CPU" + */ + +unsigned int ipi_timer_latch[NR_CPUS]; + +/* + * Number of InterProcessor Interupt (IPI) message buffers to allocate + */ + +#define IPIBUF_PER_CPU 4 + +struct smtc_ipi_q IPIQ[NR_CPUS]; +struct smtc_ipi_q freeIPIq; + + +/* Forward declarations */ + +void ipi_decode(struct pt_regs *, struct smtc_ipi *); +void post_direct_ipi(int cpu, struct smtc_ipi *pipi); +void setup_cross_vpe_interrupts(void); +void init_smtc_stats(void); + +/* Global SMTC Status */ + +unsigned int smtc_status = 0; + +/* Boot command line configuration overrides */ + +static int vpelimit = 0; +static int tclimit = 0; +static int ipibuffers = 0; +static int nostlb = 0; +static int asidmask = 0; +unsigned long smtc_asid_mask = 0xff; + +static int __init maxvpes(char *str) +{ + get_option(&str, &vpelimit); + return 1; +} + +static int __init maxtcs(char *str) +{ + get_option(&str, &tclimit); + return 1; +} + +static int __init ipibufs(char *str) +{ + get_option(&str, &ipibuffers); + return 1; +} + +static int __init stlb_disable(char *s) +{ + nostlb = 1; + return 1; +} + +static int __init asidmask_set(char *str) +{ + get_option(&str, &asidmask); + switch(asidmask) { + case 0x1: + case 0x3: + case 0x7: + case 0xf: + case 0x1f: + case 0x3f: + case 0x7f: + case 0xff: + smtc_asid_mask = (unsigned long)asidmask; + break; + default: + printk("ILLEGAL ASID mask 0x%x from command line\n", asidmask); + } + return 1; +} + +__setup("maxvpes=", maxvpes); +__setup("maxtcs=", maxtcs); +__setup("ipibufs=", ipibufs); +__setup("nostlb", stlb_disable); +__setup("asidmask=", asidmask_set); + +/* Enable additional debug checks before going into CPU idle loop */ +#define SMTC_IDLE_HOOK_DEBUG + +#ifdef SMTC_IDLE_HOOK_DEBUG + +static int hang_trig = 0; + +static int __init hangtrig_enable(char *s) +{ + hang_trig = 1; + return 1; +} + + +__setup("hangtrig", hangtrig_enable); + +#define DEFAULT_BLOCKED_IPI_LIMIT 32 + +static int timerq_limit = DEFAULT_BLOCKED_IPI_LIMIT; + +static int __init tintq(char *str) +{ + get_option(&str, &timerq_limit); + return 1; +} + +__setup("tintq=", tintq); + +int imstuckcount[2][8]; +/* vpemask represents IM/IE bits of per-VPE Status registers, low-to-high */ +int vpemask[2][8] = {{0,1,1,0,0,0,0,1},{0,1,0,0,0,0,0,1}}; +int tcnoprog[NR_CPUS]; +static atomic_t idle_hook_initialized = {0}; +static int clock_hang_reported[NR_CPUS]; + +#endif /* SMTC_IDLE_HOOK_DEBUG */ + +/* Initialize shared TLB - the should probably migrate to smtc_setup_cpus() */ + +void __init sanitize_tlb_entries(void) +{ + printk("Deprecated sanitize_tlb_entries() invoked\n"); +} + + +/* + * Configure shared TLB - VPC configuration bit must be set by caller + */ + +void smtc_configure_tlb(void) +{ + int i,tlbsiz,vpes; + unsigned long mvpconf0; + unsigned long config1val; + + /* Set up ASID preservation table */ + for (vpes=0; vpes<MAX_SMTC_TLBS; vpes++) { + for(i = 0; i < MAX_SMTC_ASIDS; i++) { + smtc_live_asid[vpes][i] = 0; + } + } + mvpconf0 = read_c0_mvpconf0(); + + if ((vpes = ((mvpconf0 & MVPCONF0_PVPE) + >> MVPCONF0_PVPE_SHIFT) + 1) > 1) { + /* If we have multiple VPEs, try to share the TLB */ + if ((mvpconf0 & MVPCONF0_TLBS) && !nostlb) { + /* + * If TLB sizing is programmable, shared TLB + * size is the total available complement. + * Otherwise, we have to take the sum of all + * static VPE TLB entries. + */ + if ((tlbsiz = ((mvpconf0 & MVPCONF0_PTLBE) + >> MVPCONF0_PTLBE_SHIFT)) == 0) { + /* + * If there's more than one VPE, there had better + * be more than one TC, because we need one to bind + * to each VPE in turn to be able to read + * its configuration state! + */ + settc(1); + /* Stop the TC from doing anything foolish */ + write_tc_c0_tchalt(TCHALT_H); + mips_ihb(); + /* No need to un-Halt - that happens later anyway */ + for (i=0; i < vpes; i++) { + write_tc_c0_tcbind(i); + /* + * To be 100% sure we're really getting the right + * information, we exit the configuration state + * and do an IHB after each rebinding. + */ + write_c0_mvpcontrol( + read_c0_mvpcontrol() & ~ MVPCONTROL_VPC ); + mips_ihb(); + /* + * Only count if the MMU Type indicated is TLB + */ + if(((read_vpe_c0_config() & MIPS_CONF_MT) >> 7) == 1) { + config1val = read_vpe_c0_config1(); + tlbsiz += ((config1val >> 25) & 0x3f) + 1; + } + + /* Put core back in configuration state */ + write_c0_mvpcontrol( + read_c0_mvpcontrol() | MVPCONTROL_VPC ); + mips_ihb(); + } + } + write_c0_mvpcontrol(read_c0_mvpcontrol() | MVPCONTROL_STLB); + + /* + * Setup kernel data structures to use software total, + * rather than read the per-VPE Config1 value. The values + * for "CPU 0" gets copied to all the other CPUs as part + * of their initialization in smtc_cpu_setup(). + */ + + tlbsiz = tlbsiz & 0x3f; /* MIPS32 limits TLB indices to 64 */ + cpu_data[0].tlbsize = tlbsiz; + smtc_status |= SMTC_TLB_SHARED; + + printk("TLB of %d entry pairs shared by %d VPEs\n", + tlbsiz, vpes); + } else { + printk("WARNING: TLB Not Sharable on SMTC Boot!\n"); + } + } +} + + +/* + * Incrementally build the CPU map out of constituent MIPS MT cores, + * using the specified available VPEs and TCs. Plaform code needs + * to ensure that each MIPS MT core invokes this routine on reset, + * one at a time(!). + * + * This version of the build_cpu_map and prepare_cpus routines assumes + * that *all* TCs of a MIPS MT core will be used for Linux, and that + * they will be spread across *all* available VPEs (to minimise the + * loss of efficiency due to exception service serialization). + * An improved version would pick up configuration information and + * possibly leave some TCs/VPEs as "slave" processors. + * + * Use c0_MVPConf0 to find out how many TCs are available, setting up + * phys_cpu_present_map and the logical/physical mappings. + */ + +int __init mipsmt_build_cpu_map(int start_cpu_slot) +{ + int i, ntcs; + + /* + * The CPU map isn't actually used for anything at this point, + * so it's not clear what else we should do apart from set + * everything up so that "logical" = "physical". + */ + ntcs = ((read_c0_mvpconf0() & MVPCONF0_PTC) >> MVPCONF0_PTC_SHIFT) + 1; + for (i=start_cpu_slot; i<NR_CPUS && i<ntcs; i++) { + cpu_set(i, phys_cpu_present_map); + __cpu_number_map[i] = i; + __cpu_logical_map[i] = i; + } + /* Initialize map of CPUs with FPUs */ + cpus_clear(mt_fpu_cpumask); + + /* One of those TC's is the one booting, and not a secondary... */ + printk("%i available secondary CPU TC(s)\n", i - 1); + + return i; +} + +/* + * Common setup before any secondaries are started + * Make sure all CPU's are in a sensible state before we boot any of the + * secondaries. + * + * For MIPS MT "SMTC" operation, we set up all TCs, spread as evenly + * as possible across the available VPEs. + */ + +static void smtc_tc_setup(int vpe, int tc, int cpu) +{ + settc(tc); + write_tc_c0_tchalt(TCHALT_H); + mips_ihb(); + write_tc_c0_tcstatus((read_tc_c0_tcstatus() + & ~(TCSTATUS_TKSU | TCSTATUS_DA | TCSTATUS_IXMT)) + | TCSTATUS_A); + write_tc_c0_tccontext(0); + /* Bind tc to vpe */ + write_tc_c0_tcbind(vpe); + /* In general, all TCs should have the same cpu_data indications */ + memcpy(&cpu_data[cpu], &cpu_data[0], sizeof(struct cpuinfo_mips)); + /* For 34Kf, start with TC/CPU 0 as sole owner of single FPU context */ + if (cpu_data[0].cputype == CPU_34K) + cpu_data[cpu].options &= ~MIPS_CPU_FPU; + cpu_data[cpu].vpe_id = vpe; + cpu_data[cpu].tc_id = tc; +} + + +void mipsmt_prepare_cpus(void) +{ + int i, vpe, tc, ntc, nvpe, tcpervpe, slop, cpu; + unsigned long flags; + unsigned long val; + int nipi; + struct smtc_ipi *pipi; + + /* disable interrupts so we can disable MT */ + local_irq_save(flags); + /* disable MT so we can configure */ + dvpe(); + dmt(); + + freeIPIq.lock = SPIN_LOCK_UNLOCKED; + + /* + * We probably don't have as many VPEs as we do SMP "CPUs", + * but it's possible - and in any case we'll never use more! + */ + for (i=0; i<NR_CPUS; i++) { + IPIQ[i].head = IPIQ[i].tail = NULL; + IPIQ[i].lock = SPIN_LOCK_UNLOCKED; + IPIQ[i].depth = 0; + 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++; + + /* Report on boot-time options */ + mips_mt_set_cpuoptions (); + if (vpelimit > 0) + printk("Limit of %d VPEs set\n", vpelimit); + if (tclimit > 0) + printk("Limit of %d TCs set\n", tclimit); + if (nostlb) { + printk("Shared TLB Use Inhibited - UNSAFE for Multi-VPE Operation\n"); + } + if (asidmask) + printk("ASID mask value override to 0x%x\n", asidmask); + + /* Temporary */ +#ifdef SMTC_IDLE_HOOK_DEBUG + if (hang_trig) + printk("Logic Analyser Trigger on suspected TC hang\n"); +#endif /* SMTC_IDLE_HOOK_DEBUG */ + + /* Put MVPE's into 'configuration state' */ + write_c0_mvpcontrol( read_c0_mvpcontrol() | MVPCONTROL_VPC ); + + val = read_c0_mvpconf0(); + nvpe = ((val & MVPCONF0_PVPE) >> MVPCONF0_PVPE_SHIFT) + 1; + if (vpelimit > 0 && nvpe > vpelimit) + nvpe = vpelimit; + ntc = ((val & MVPCONF0_PTC) >> MVPCONF0_PTC_SHIFT) + 1; + if (ntc > NR_CPUS) + ntc = NR_CPUS; + if (tclimit > 0 && ntc > tclimit) + ntc = tclimit; + tcpervpe = ntc / nvpe; + slop = ntc % nvpe; /* Residual TCs, < NVPE */ + + /* Set up shared TLB */ + smtc_configure_tlb(); + + for (tc = 0, vpe = 0 ; (vpe < nvpe) && (tc < ntc) ; vpe++) { + /* + * Set the MVP bits. + */ + settc(tc); + write_vpe_c0_vpeconf0(read_vpe_c0_vpeconf0() | VPECONF0_MVP); + if (vpe != 0) + printk(", "); + printk("VPE %d: TC", vpe); + for (i = 0; i < tcpervpe; i++) { + /* + * TC 0 is bound to VPE 0 at reset, + * and is presumably executing this + * code. Leave it alone! + */ + if (tc != 0) { + smtc_tc_setup(vpe,tc, cpu); + cpu++; + } + printk(" %d", tc); + tc++; + } + if (slop) { + if (tc != 0) { + smtc_tc_setup(vpe,tc, cpu); + cpu++; + } + printk(" %d", tc); + tc++; + slop--; + } + if (vpe != 0) { + /* + * Clear any stale software interrupts from VPE's Cause + */ + write_vpe_c0_cause(0); + + /* + * Clear ERL/EXL of VPEs other than 0 + * and set restricted interrupt enable/mask. + */ + write_vpe_c0_status((read_vpe_c0_status() + & ~(ST0_BEV | ST0_ERL | ST0_EXL | ST0_IM)) + | (STATUSF_IP0 | STATUSF_IP1 | STATUSF_IP7 + | ST0_IE)); + /* + * set config to be the same as vpe0, + * particularly kseg0 coherency alg + */ + write_vpe_c0_config(read_c0_config()); + /* Clear any pending timer interrupt */ + write_vpe_c0_compare(0); + /* Propagate Config7 */ + write_vpe_c0_config7(read_c0_config7()); + } + /* enable multi-threading within VPE */ + write_vpe_c0_vpecontrol(read_vpe_c0_vpecontrol() | VPECONTROL_TE); + /* enable the VPE */ + write_vpe_c0_vpeconf0(read_vpe_c0_vpeconf0() | VPECONF0_VPA); + } + + /* + * Pull any physically present but unused TCs out of circulation. + */ + while (tc < (((val & MVPCONF0_PTC) >> MVPCONF0_PTC_SHIFT) + 1)) { + cpu_clear(tc, phys_cpu_present_map); + cpu_clear(tc, cpu_present_map); + tc++; + } + + /* release config state */ + write_c0_mvpcontrol( read_c0_mvpcontrol() & ~ MVPCONTROL_VPC ); + + printk("\n"); + + /* Set up coprocessor affinity CPU mask(s) */ + + for (tc = 0; tc < ntc; tc++) { + if(cpu_data[tc].options & MIPS_CPU_FPU) + cpu_set(tc, mt_fpu_cpumask); + } + + /* set up ipi interrupts... */ + + /* If we have multiple VPEs running, set up the cross-VPE interrupt */ + + if (nvpe > 1) + setup_cross_vpe_interrupts(); + + /* Set up queue of free IPI "messages". */ + nipi = NR_CPUS * IPIBUF_PER_CPU; + if (ipibuffers > 0) + nipi = ipibuffers; + + pipi = kmalloc(nipi *sizeof(struct smtc_ipi), GFP_KERNEL); + if (pipi == NULL) + panic("kmalloc of IPI message buffers failed\n"); + else + printk("IPI buffer pool of %d buffers\n", nipi); + for (i = 0; i < nipi; i++) { + smtc_ipi_nq(&freeIPIq, pipi); + pipi++; + } + + /* Arm multithreading and enable other VPEs - but all TCs are Halted */ + emt(EMT_ENABLE); + evpe(EVPE_ENABLE); + local_irq_restore(flags); + /* Initialize SMTC /proc statistics/diagnostics */ + init_smtc_stats(); +} + + +/* + * Setup the PC, SP, and GP of a secondary processor and start it + * running! + * smp_bootstrap is the place to resume from + * __KSTK_TOS(idle) is apparently the stack pointer + * (unsigned long)idle->thread_info the gp + * + */ +void smtc_boot_secondary(int cpu, struct task_struct *idle) +{ + extern u32 kernelsp[NR_CPUS]; + long flags; + int mtflags; + + LOCK_MT_PRA(); + if (cpu_data[cpu].vpe_id != cpu_data[smp_processor_id()].vpe_id) { + dvpe(); + } + settc(cpu_data[cpu].tc_id); + + /* pc */ + write_tc_c0_tcrestart((unsigned long)&smp_bootstrap); + + /* stack pointer */ + kernelsp[cpu] = __KSTK_TOS(idle); + write_tc_gpr_sp(__KSTK_TOS(idle)); + + /* global pointer */ + write_tc_gpr_gp((unsigned long)idle->thread_info); + + smtc_status |= SMTC_MTC_ACTIVE; + write_tc_c0_tchalt(0); + if (cpu_data[cpu].vpe_id != cpu_data[smp_processor_id()].vpe_id) { + evpe(EVPE_ENABLE); + } + UNLOCK_MT_PRA(); +} + +void smtc_init_secondary(void) +{ + /* + * Start timer on secondary VPEs if necessary. + * mips_timer_setup should 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) +{ + printk("TC %d going on-line as CPU %d\n", + cpu_data[smp_processor_id()].tc_id, smp_processor_id()); +} + +void smtc_cpus_done(void) +{ +} + +/* + * Support for SMTC-optimized driver IRQ registration + */ + +/* + * SMTC Kernel needs to manipulate low-level CPU interrupt mask + * in do_IRQ. These are passed in setup_irq_smtc() and stored + * in this table. + */ + +int setup_irq_smtc(unsigned int irq, struct irqaction * new, + unsigned long hwmask) +{ + irq_hwmask[irq] = hwmask; + + return setup_irq(irq, new); +} + +/* + * IPI model for SMTC is tricky, because interrupts aren't TC-specific. + * Within a VPE one TC can interrupt another by different approaches. + * The easiest to get right would probably be to make all TCs except + * the target IXMT and set a software interrupt, but an IXMT-based + * scheme requires that a handler must run before a new IPI could + * be sent, which would break the "broadcast" loops in MIPS MT. + * A more gonzo approach within a VPE is to halt the TC, extract + * its Restart, Status, and a couple of GPRs, and program the Restart + * address to emulate an interrupt. + * + * Within a VPE, one can be confident that the target TC isn't in + * a critical EXL state when halted, since the write to the Halt + * register could not have issued on the writing thread if the + * halting thread had EXL set. So k0 and k1 of the target TC + * can be used by the injection code. Across VPEs, one can't + * be certain that the target TC isn't in a critical exception + * state. So we try a two-step process of sending a software + * interrupt to the target VPE, which either handles the event + * itself (if it was the target) or injects the event within + * the VPE. + */ + +void smtc_ipi_qdump(void) +{ + int i; + + for (i = 0; i < NR_CPUS ;i++) { + printk("IPIQ[%d]: head = 0x%x, tail = 0x%x, depth = %d\n", + i, (unsigned)IPIQ[i].head, (unsigned)IPIQ[i].tail, + IPIQ[i].depth); + } +} + +/* + * The standard atomic.h primitives don't quite do what we want + * here: We need an atomic add-and-return-previous-value (which + * could be done with atomic_add_return and a decrement) and an + * atomic set/zero-and-return-previous-value (which can't really + * be done with the atomic.h primitives). And since this is + * MIPS MT, we can assume that we have LL/SC. + */ +static __inline__ int atomic_postincrement(unsigned int *pv) +{ + unsigned long result; + + unsigned long temp; + + __asm__ __volatile__( + "1: ll %0, %2 \n" + " addu %1, %0, 1 \n" + " sc %1, %2 \n" + " beqz %1, 1b \n" + " sync \n" + : "=&r" (result), "=&r" (temp), "=m" (*pv) + : "m" (*pv) + : "memory"); + + return result; +} + +/* No longer used in IPI dispatch, but retained for future recycling */ + +static __inline__ int atomic_postclear(unsigned int *pv) +{ + unsigned long result; + + unsigned long temp; + + __asm__ __volatile__( + "1: ll %0, %2 \n" + " or %1, $0, $0 \n" + " sc %1, %2 \n" + " beqz %1, 1b \n" + " sync \n" + : "=&r" (result), "=&r" (temp), "=m" (*pv) + : "m" (*pv) + : "memory"); + + return result; +} + + +void smtc_send_ipi(int cpu, int type, unsigned int action) +{ + int tcstatus; + struct smtc_ipi *pipi; + long flags; + int mtflags; + + if (cpu == smp_processor_id()) { + printk("Cannot Send IPI to self!\n"); + return; + } + /* Set up a descriptor, to be delivered either promptly or queued */ + pipi = smtc_ipi_dq(&freeIPIq); + if (pipi == NULL) { + bust_spinlocks(1); + mips_mt_regdump(dvpe()); + panic("IPI Msg. Buffers Depleted\n"); + } + pipi->type = type; + pipi->arg = (void *)action; + pipi->dest = cpu; + if (cpu_data[cpu].vpe_id != cpu_data[smp_processor_id()].vpe_id) { + /* If not on same VPE, enqueue and send cross-VPE interupt */ + smtc_ipi_nq(&IPIQ[cpu], pipi); + LOCK_CORE_PRA(); + settc(cpu_data[cpu].tc_id); + write_vpe_c0_cause(read_vpe_c0_cause() | C_SW1); + UNLOCK_CORE_PRA(); + } else { + /* + * Not sufficient to do a LOCK_MT_PRA (dmt) here, + * since ASID shootdown on the other VPE may + * collide with this operation. + */ + LOCK_CORE_PRA(); + settc(cpu_data[cpu].tc_id); + /* Halt the targeted TC */ + write_tc_c0_tchalt(TCHALT_H); + mips_ihb(); + + /* + * Inspect TCStatus - if IXMT is set, we have to queue + * a message. Otherwise, we set up the "interrupt" + * of the other TC + */ + tcstatus = read_tc_c0_tcstatus(); + + if ((tcstatus & TCSTATUS_IXMT) != 0) { + /* + * Spin-waiting here can deadlock, + * so we queue the message for the target TC. + */ + 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 { + post_direct_ipi(cpu, pipi); + write_tc_c0_tchalt(0); + UNLOCK_CORE_PRA(); + } + } +} + +/* + * Send IPI message to Halted TC, TargTC/TargVPE already having been set + */ +void post_direct_ipi(int cpu, struct smtc_ipi *pipi) +{ + struct pt_regs *kstack; + unsigned long tcstatus; + unsigned long tcrestart; + extern u32 kernelsp[NR_CPUS]; + extern void __smtc_ipi_vector(void); + + /* Extract Status, EPC from halted TC */ + tcstatus = read_tc_c0_tcstatus(); + tcrestart = read_tc_c0_tcrestart(); + /* If TCRestart indicates a WAIT instruction, advance the PC */ + if ((tcrestart & 0x80000000) + && ((*(unsigned int *)tcrestart & 0xfe00003f) == 0x42000020)) { + tcrestart += 4; + } + /* + * Save on TC's future kernel stack + * + * CU bit of Status is indicator that TC was + * already running on a kernel stack... + */ + if(tcstatus & ST0_CU0) { + /* Note that this "- 1" is pointer arithmetic */ + kstack = ((struct pt_regs *)read_tc_gpr_sp()) - 1; + } else { + kstack = ((struct pt_regs *)kernelsp[cpu]) - 1; + } + + kstack->cp0_epc = (long)tcrestart; + /* Save TCStatus */ + kstack->cp0_tcstatus = tcstatus; + /* Pass token of operation to be performed kernel stack pad area */ + kstack->pad0[4] = (unsigned long)pipi; + /* Pass address of function to be called likewise */ + kstack->pad0[5] = (unsigned long)&ipi_decode; + /* Set interrupt exempt and kernel mode */ + tcstatus |= TCSTATUS_IXMT; + tcstatus &= ~TCSTATUS_TKSU; + write_tc_c0_tcstatus(tcstatus); + ehb(); + /* Set TC Restart address to be SMTC IPI vector */ + write_tc_c0_tcrestart(__smtc_ipi_vector); +} + +void ipi_resched_interrupt(struct pt_regs *regs) +{ + /* Return from interrupt should be enough to cause scheduler check */ +} + + +void ipi_call_interrupt(struct pt_regs *regs) +{ + /* Invoke generic function invocation code in smp.c */ + smp_call_function_interrupt(); +} + +void ipi_decode(struct pt_regs *regs, struct smtc_ipi *pipi) +{ + void *arg_copy = pipi->arg; + int type_copy = pipi->type; + int dest_copy = pipi->dest; + + smtc_ipi_nq(&freeIPIq, pipi); + switch (type_copy) { + case SMTC_CLOCK_TICK: + /* Invoke Clock "Interrupt" */ + ipi_timer_latch[dest_copy] = 0; +#ifdef SMTC_IDLE_HOOK_DEBUG + clock_hang_reported[dest_copy] = 0; +#endif /* SMTC_IDLE_HOOK_DEBUG */ + local_timer_interrupt(0, NULL, regs); + break; + case LINUX_SMP_IPI: + switch ((int)arg_copy) { + case SMP_RESCHEDULE_YOURSELF: + ipi_resched_interrupt(regs); + break; + case SMP_CALL_FUNCTION: + ipi_call_interrupt(regs); + break; + default: + printk("Impossible SMTC IPI Argument 0x%x\n", + (int)arg_copy); + break; + } + break; + default: + printk("Impossible SMTC IPI Type 0x%x\n", type_copy); + break; + } +} + +void deferred_smtc_ipi(struct pt_regs *regs) +{ + struct smtc_ipi *pipi; + unsigned long flags; +/* DEBUG */ + int q = 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(IPIQ[q].head != NULL) { + while((pipi = smtc_ipi_dq(&IPIQ[q])) != NULL) { + /* ipi_decode() should be called with interrupts off */ + local_irq_save(flags); + ipi_decode(regs, pipi); + local_irq_restore(flags); + } + } +} + +/* + * Send clock tick to all TCs except the one executing the funtion + */ + +void smtc_timer_broadcast(int vpe) +{ + int cpu; + int myTC = cpu_data[smp_processor_id()].tc_id; + int myVPE = cpu_data[smp_processor_id()].vpe_id; + + smtc_cpu_stats[smp_processor_id()].timerints++; + + for_each_online_cpu(cpu) { + if (cpu_data[cpu].vpe_id == myVPE && + cpu_data[cpu].tc_id != myTC) + smtc_send_ipi(cpu, SMTC_CLOCK_TICK, 0); + } +} + +/* + * Cross-VPE interrupts in the SMTC prototype use "software interrupts" + * set via cross-VPE MTTR manipulation of the Cause register. It would be + * in some regards preferable to have external logic for "doorbell" hardware + * interrupts. + */ + +static int cpu_ipi_irq = MIPSCPU_INT_BASE + MIPS_CPU_IPI_IRQ; + +static irqreturn_t ipi_interrupt(int irq, void *dev_idm, struct pt_regs *regs) +{ + int my_vpe = cpu_data[smp_processor_id()].vpe_id; + int my_tc = cpu_data[smp_processor_id()].tc_id; + int cpu; + struct smtc_ipi *pipi; + unsigned long tcstatus; + int sent; + long flags; + unsigned int mtflags; + unsigned int vpflags; + + /* + * So long as cross-VPE interrupts are done via + * MFTR/MTTR read-modify-writes of Cause, we need + * to stop other VPEs whenever the local VPE does + * anything similar. + */ + local_irq_save(flags); + vpflags = dvpe(); + clear_c0_cause(0x100 << MIPS_CPU_IPI_IRQ); + set_c0_status(0x100 << MIPS_CPU_IPI_IRQ); + irq_enable_hazard(); + evpe(vpflags); + local_irq_restore(flags); + + /* + * Cross-VPE Interrupt handler: Try to directly deliver IPIs + * queued for TCs on this VPE other than the current one. + * Return-from-interrupt should cause us to drain the queue + * for the current TC, so we ought not to have to do it explicitly here. + */ + + for_each_online_cpu(cpu) { + if (cpu_data[cpu].vpe_id != my_vpe) + continue; + + pipi = smtc_ipi_dq(&IPIQ[cpu]); + if (pipi != NULL) { + if (cpu_data[cpu].tc_id != my_tc) { + sent = 0; + LOCK_MT_PRA(); + settc(cpu_data[cpu].tc_id); + write_tc_c0_tchalt(TCHALT_H); + mips_ihb(); + tcstatus = read_tc_c0_tcstatus(); + if ((tcstatus & TCSTATUS_IXMT) == 0) { + post_direct_ipi(cpu, pipi); + sent = 1; + } + write_tc_c0_tchalt(0); + UNLOCK_MT_PRA(); + if (!sent) { + smtc_ipi_req(&IPIQ[cpu], pipi); + } + } else { + /* + * ipi_decode() should be called + * with interrupts off + */ + local_irq_save(flags); + ipi_decode(regs, pipi); + local_irq_restore(flags); + } + } + } + + return IRQ_HANDLED; +} + +static void ipi_irq_dispatch(struct pt_regs *regs) +{ + do_IRQ(cpu_ipi_irq, regs); +} + +static struct irqaction irq_ipi; + +void setup_cross_vpe_interrupts(void) +{ + if (!cpu_has_vint) + panic("SMTC Kernel requires Vectored Interupt support"); + + set_vi_handler(MIPS_CPU_IPI_IRQ, ipi_irq_dispatch); + + irq_ipi.handler = ipi_interrupt; + irq_ipi.flags = SA_INTERRUPT; + irq_ipi.name = "SMTC_IPI"; + + setup_irq_smtc(cpu_ipi_irq, &irq_ipi, (0x100 << MIPS_CPU_IPI_IRQ)); + + irq_desc[cpu_ipi_irq].status |= IRQ_PER_CPU; +} + +/* + * SMTC-specific hacks invoked from elsewhere in the kernel. + */ + +void smtc_idle_loop_hook(void) +{ +#ifdef SMTC_IDLE_HOOK_DEBUG + int im; + int flags; + int mtflags; + int bit; + int vpe; + int tc; + int hook_ntcs; + /* + * printk within DMT-protected regions can deadlock, + * so buffer diagnostic messages for later output. + */ + char *pdb_msg; + char id_ho_db_msg[768]; /* worst-case use should be less than 700 */ + + if (atomic_read(&idle_hook_initialized) == 0) { /* fast test */ + if (atomic_add_return(1, &idle_hook_initialized) == 1) { + int mvpconf0; + /* Tedious stuff to just do once */ + mvpconf0 = read_c0_mvpconf0(); + hook_ntcs = ((mvpconf0 & MVPCONF0_PTC) >> MVPCONF0_PTC_SHIFT) + 1; + if (hook_ntcs > NR_CPUS) + hook_ntcs = NR_CPUS; + for (tc = 0; tc < hook_ntcs; tc++) { + tcnoprog[tc] = 0; + clock_hang_reported[tc] = 0; + } + for (vpe = 0; vpe < 2; vpe++) + for (im = 0; im < 8; im++) + imstuckcount[vpe][im] = 0; + printk("Idle loop test hook initialized for %d TCs\n", hook_ntcs); + atomic_set(&idle_hook_initialized, 1000); + } else { + /* Someone else is initializing in parallel - let 'em finish */ + while (atomic_read(&idle_hook_initialized) < 1000) + ; + } + } + + /* Have we stupidly left IXMT set somewhere? */ + if (read_c0_tcstatus() & 0x400) { + write_c0_tcstatus(read_c0_tcstatus() & ~0x400); + ehb(); + printk("Dangling IXMT in cpu_idle()\n"); + } + + /* Have we stupidly left an IM bit turned off? */ +#define IM_LIMIT 2000 + local_irq_save(flags); + mtflags = dmt(); + pdb_msg = &id_ho_db_msg[0]; + im = read_c0_status(); + vpe = cpu_data[smp_processor_id()].vpe_id; + for (bit = 0; bit < 8; bit++) { + /* + * In current prototype, I/O interrupts + * are masked for VPE > 0 + */ + if (vpemask[vpe][bit]) { + if (!(im & (0x100 << bit))) + imstuckcount[vpe][bit]++; + else + imstuckcount[vpe][bit] = 0; + if (imstuckcount[vpe][bit] > IM_LIMIT) { + set_c0_status(0x100 << bit); + ehb(); + imstuckcount[vpe][bit] = 0; + pdb_msg += sprintf(pdb_msg, + "Dangling IM %d fixed for VPE %d\n", bit, + vpe); + } + } + } + + /* + * 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()) && + 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, 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 /* SMTC_IDLE_HOOK_DEBUG */ + /* + * 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. + */ + if (IPIQ[smp_processor_id()].depth > 0) { + struct smtc_ipi *pipi; + extern void self_ipi(struct smtc_ipi *); + + if ((pipi = smtc_ipi_dq(&IPIQ[smp_processor_id()])) != NULL) { + self_ipi(pipi); + smtc_cpu_stats[smp_processor_id()].selfipis++; + } + } +} + +void smtc_soft_dump(void) +{ + int i; + + printk("Counter Interrupts taken per CPU (TC)\n"); + for (i=0; i < NR_CPUS; i++) { + printk("%d: %ld\n", i, smtc_cpu_stats[i].timerints); + } + printk("Self-IPI invocations:\n"); + for (i=0; i < NR_CPUS; i++) { + 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, ipi_timer_latch[i]); + } + printk("%d Recoveries of \"stolen\" FPU\n", + atomic_read(&smtc_fpu_recoveries)); +} + + +/* + * TLB management routines special to SMTC + */ + +void smtc_get_new_mmu_context(struct mm_struct *mm, unsigned long cpu) +{ + unsigned long flags, mtflags, tcstat, prevhalt, asid; + int tlb, i; + + /* + * It would be nice to be able to use a spinlock here, + * but this is invoked from within TLB flush routines + * that protect themselves with DVPE, so if a lock is + * held by another TC, it'll never be freed. + * + * DVPE/DMT must not be done with interrupts enabled, + * so even so most callers will already have disabled + * them, let's be really careful... + */ + + local_irq_save(flags); + if (smtc_status & SMTC_TLB_SHARED) { + mtflags = dvpe(); + tlb = 0; + } else { + mtflags = dmt(); + tlb = cpu_data[cpu].vpe_id; + } + asid = asid_cache(cpu); + + do { + if (!((asid += ASID_INC) & ASID_MASK) ) { + if (cpu_has_vtag_icache) + flush_icache_all(); + /* Traverse all online CPUs (hack requires contigous range) */ + for (i = 0; i < num_online_cpus(); i++) { + /* + * We don't need to worry about our own CPU, nor those of + * CPUs who don't share our TLB. + */ + if ((i != smp_processor_id()) && + ((smtc_status & SMTC_TLB_SHARED) || + (cpu_data[i].vpe_id == cpu_data[cpu].vpe_id))) { + settc(cpu_data[i].tc_id); + prevhalt = read_tc_c0_tchalt() & TCHALT_H; + if (!prevhalt) { + write_tc_c0_tchalt(TCHALT_H); + mips_ihb(); + } + tcstat = read_tc_c0_tcstatus(); + smtc_live_asid[tlb][(tcstat & ASID_MASK)] |= (asiduse)(0x1 << i); + if (!prevhalt) + write_tc_c0_tchalt(0); + } + } + if (!asid) /* fix version if needed */ + asid = ASID_FIRST_VERSION; + local_flush_tlb_all(); /* start new asid cycle */ + } + } while (smtc_live_asid[tlb][(asid & ASID_MASK)]); + + /* + * SMTC shares the TLB within VPEs and possibly across all VPEs. + */ + for (i = 0; i < num_online_cpus(); i++) { + if ((smtc_status & SMTC_TLB_SHARED) || + (cpu_data[i].vpe_id == cpu_data[cpu].vpe_id)) + cpu_context(i, mm) = asid_cache(i) = asid; + } + + if (smtc_status & SMTC_TLB_SHARED) + evpe(mtflags); + else + emt(mtflags); + local_irq_restore(flags); +} + +/* + * Invoked from macros defined in mmu_context.h + * which must already have disabled interrupts + * and done a DVPE or DMT as appropriate. + */ + +void smtc_flush_tlb_asid(unsigned long asid) +{ + int entry; + unsigned long ehi; + + entry = read_c0_wired(); + + /* Traverse all non-wired entries */ + while (entry < current_cpu_data.tlbsize) { + write_c0_index(entry); + ehb(); + tlb_read(); + ehb(); + ehi = read_c0_entryhi(); + if((ehi & ASID_MASK) == asid) { + /* + * Invalidate only entries with specified ASID, + * makiing sure all entries differ. + */ + write_c0_entryhi(CKSEG0 + (entry << (PAGE_SHIFT + 1))); + write_c0_entrylo0(0); + write_c0_entrylo1(0); + mtc0_tlbw_hazard(); + tlb_write_indexed(); + } + entry++; + } + write_c0_index(PARKED_INDEX); + tlbw_use_hazard(); +} + +/* + * Support for single-threading cache flush operations. + */ + +int halt_state_save[NR_CPUS]; + +/* + * To really, really be sure that nothing is being done + * by other TCs, halt them all. This code assumes that + * a DVPE has already been done, so while their Halted + * state is theoretically architecturally unstable, in + * practice, it's not going to change while we're looking + * at it. + */ + +void smtc_cflush_lockdown(void) +{ + int cpu; + + for_each_online_cpu(cpu) { + if (cpu != smp_processor_id()) { + settc(cpu_data[cpu].tc_id); + halt_state_save[cpu] = read_tc_c0_tchalt(); + write_tc_c0_tchalt(TCHALT_H); + } + } + mips_ihb(); +} + +/* It would be cheating to change the cpu_online states during a flush! */ + +void smtc_cflush_release(void) +{ + int cpu; + + /* + * Start with a hazard barrier to ensure + * that all CACHE ops have played through. + */ + mips_ihb(); + + for_each_online_cpu(cpu) { + if (cpu != smp_processor_id()) { + settc(cpu_data[cpu].tc_id); + write_tc_c0_tchalt(halt_state_save[cpu]); + } + } + mips_ihb(); +} |