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freebsd-dev/sys/amd64/amd64/mp_machdep.c
David E. O'Brien 5a3b7e5e5c Document machdep.hlt_cpus. 
Submitted by:	Craig Rodrigues <rodrigc@crodrigues.org>
2004-03-18 02:53:38 +00:00

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/*-
* Copyright (c) 1996, by Steve Passe
* Copyright (c) 2003, by Peter Wemm
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. The name of the developer may NOT be used to endorse or promote products
* derived from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include "opt_cpu.h"
#include "opt_kstack_pages.h"
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/bus.h>
#ifdef GPROF
#include <sys/gmon.h>
#endif
#include <sys/kernel.h>
#include <sys/ktr.h>
#include <sys/lock.h>
#include <sys/malloc.h>
#include <sys/memrange.h>
#include <sys/mutex.h>
#include <sys/pcpu.h>
#include <sys/proc.h>
#include <sys/smp.h>
#include <sys/sysctl.h>
#include <vm/vm.h>
#include <vm/vm_param.h>
#include <vm/pmap.h>
#include <vm/vm_kern.h>
#include <vm/vm_extern.h>
#include <machine/apicreg.h>
#include <machine/clock.h>
#include <machine/md_var.h>
#include <machine/pcb.h>
#include <machine/psl.h>
#include <machine/smp.h>
#include <machine/specialreg.h>
#include <machine/tss.h>
#define WARMBOOT_TARGET 0
#define WARMBOOT_OFF (KERNBASE + 0x0467)
#define WARMBOOT_SEG (KERNBASE + 0x0469)
#define CMOS_REG (0x70)
#define CMOS_DATA (0x71)
#define BIOS_RESET (0x0f)
#define BIOS_WARM (0x0a)
/* lock region used by kernel profiling */
int mcount_lock;
int mp_naps; /* # of Applications processors */
int boot_cpu_id = -1; /* designated BSP */
extern int nkpt;
/*
* CPU topology map datastructures for HTT.
*/
static struct cpu_group mp_groups[MAXCPU];
static struct cpu_top mp_top;
/* AP uses this during bootstrap. Do not staticize. */
char *bootSTK;
static int bootAP;
/* Free these after use */
void *bootstacks[MAXCPU];
/* Hotwire a 0->4MB V==P mapping */
extern pt_entry_t *KPTphys;
/* SMP page table page */
extern pt_entry_t *SMPpt;
struct pcb stoppcbs[MAXCPU];
/* Variables needed for SMP tlb shootdown. */
vm_offset_t smp_tlb_addr1;
vm_offset_t smp_tlb_addr2;
volatile int smp_tlb_wait;
struct mtx smp_tlb_mtx;
extern inthand_t IDTVEC(fast_syscall), IDTVEC(fast_syscall32);
/*
* Local data and functions.
*/
static u_int logical_cpus;
static u_int logical_cpus_mask;
/* used to hold the AP's until we are ready to release them */
static struct mtx ap_boot_mtx;
/* Set to 1 once we're ready to let the APs out of the pen. */
static volatile int aps_ready = 0;
/*
* Store data from cpu_add() until later in the boot when we actually setup
* the APs.
*/
struct cpu_info {
int cpu_present:1;
int cpu_bsp:1;
} static cpu_info[MAXCPU];
static int cpu_apic_ids[MAXCPU];
static u_int boot_address;
static void set_logical_apic_ids(void);
static int start_all_aps(void);
static int start_ap(int apic_id);
static void release_aps(void *dummy);
static int hlt_cpus_mask;
static int hlt_logical_cpus;
static struct sysctl_ctx_list logical_cpu_clist;
static u_int bootMP_size;
void
mp_topology(void)
{
struct cpu_group *group;
int logical_cpus;
int apic_id;
int groups;
int cpu;
/* Build the smp_topology map. */
/* Nothing to do if there is no HTT support. */
if ((cpu_feature & CPUID_HTT) == 0)
return;
logical_cpus = (cpu_procinfo & CPUID_HTT_CORES) >> 16;
if (logical_cpus <= 1)
return;
group = &mp_groups[0];
groups = 1;
for (cpu = 0, apic_id = 0; apic_id < MAXCPU; apic_id++) {
if (!cpu_info[apic_id].cpu_present)
continue;
/*
* If the current group has members and we're not a logical
* cpu, create a new group.
*/
if (group->cg_count != 0 && (apic_id % logical_cpus) == 0) {
group++;
groups++;
}
group->cg_count++;
group->cg_mask |= 1 << cpu;
cpu++;
}
mp_top.ct_count = groups;
mp_top.ct_group = mp_groups;
smp_topology = &mp_top;
}
/*
* Calculate usable address in base memory for AP trampoline code.
*/
u_int
mp_bootaddress(u_int basemem)
{
bootMP_size = mptramp_end - mptramp_start;
boot_address = trunc_page(basemem * 1024); /* round down to 4k boundary */
if ((basemem - boot_address) < bootMP_size)
boot_address -= PAGE_SIZE; /* not enough, lower by 4k */
/* 3 levels of page table pages */
mptramp_pagetables = boot_address - (PAGE_SIZE * 3);
return mptramp_pagetables;
}
void
cpu_add(u_int apic_id, char boot_cpu)
{
if (apic_id >= MAXCPU) {
printf("SMP: CPU %d exceeds maximum CPU %d, ignoring\n",
apic_id, MAXCPU - 1);
return;
}
KASSERT(cpu_info[apic_id].cpu_present == 0, ("CPU %d added twice",
apic_id));
cpu_info[apic_id].cpu_present = 1;
if (boot_cpu) {
KASSERT(boot_cpu_id == -1,
("CPU %d claims to be BSP, but CPU %d already is", apic_id,
boot_cpu_id));
boot_cpu_id = apic_id;
cpu_info[apic_id].cpu_bsp = 1;
}
mp_ncpus++;
if (apic_id > mp_maxid)
mp_maxid = apic_id;
if (bootverbose)
printf("SMP: Added CPU %d (%s)\n", apic_id, boot_cpu ? "BSP" :
"AP");
}
void
cpu_mp_setmaxid(void)
{
/*
* mp_maxid should be already set by calls to cpu_add().
* Just sanity check its value here.
*/
if (mp_ncpus == 0)
KASSERT(mp_maxid == 0,
("%s: mp_ncpus is zero, but mp_maxid is not", __func__));
else if (mp_ncpus == 1)
mp_maxid = 0;
else
KASSERT(mp_maxid >= mp_ncpus - 1,
("%s: counters out of sync: max %d, count %d", __func__,
mp_maxid, mp_ncpus));
}
int
cpu_mp_probe(void)
{
/*
* Always record BSP in CPU map so that the mbuf init code works
* correctly.
*/
all_cpus = 1;
if (mp_ncpus == 0) {
/*
* No CPUs were found, so this must be a UP system. Setup
* the variables to represent a system with a single CPU
* with an id of 0.
*/
mp_ncpus = 1;
return (0);
}
/* At least one CPU was found. */
if (mp_ncpus == 1) {
/*
* One CPU was found, so this must be a UP system with
* an I/O APIC.
*/
mp_maxid = 0;
return (0);
}
/* At least two CPUs were found. */
return (1);
}
/*
* Initialize the IPI handlers and start up the AP's.
*/
void
cpu_mp_start(void)
{
int i;
/* Initialize the logical ID to APIC ID table. */
for (i = 0; i < MAXCPU; i++)
cpu_apic_ids[i] = -1;
/* Install an inter-CPU IPI for TLB invalidation */
setidt(IPI_INVLTLB, IDTVEC(invltlb), SDT_SYSIGT, SEL_KPL, 0);
setidt(IPI_INVLPG, IDTVEC(invlpg), SDT_SYSIGT, SEL_KPL, 0);
setidt(IPI_INVLRNG, IDTVEC(invlrng), SDT_SYSIGT, SEL_KPL, 0);
/* Install an inter-CPU IPI for forwarding hardclock() */
setidt(IPI_HARDCLOCK, IDTVEC(hardclock), SDT_SYSIGT, SEL_KPL, 0);
/* Install an inter-CPU IPI for forwarding statclock() */
setidt(IPI_STATCLOCK, IDTVEC(statclock), SDT_SYSIGT, SEL_KPL, 0);
#ifdef LAZY_SWITCH
/* Install an inter-CPU IPI for lazy pmap release */
setidt(IPI_LAZYPMAP, IDTVEC(lazypmap), SDT_SYSIGT, SEL_KPL, 0);
#endif
/* Install an inter-CPU IPI for all-CPU rendezvous */
setidt(IPI_RENDEZVOUS, IDTVEC(rendezvous), SDT_SYSIGT, SEL_KPL, 0);
/* Install an inter-CPU IPI for forcing an additional software trap */
setidt(IPI_AST, IDTVEC(cpuast), SDT_SYSIGT, SEL_KPL, 0);
/* Install an inter-CPU IPI for CPU stop/restart */
setidt(IPI_STOP, IDTVEC(cpustop), SDT_SYSIGT, SEL_KPL, 0);
mtx_init(&smp_tlb_mtx, "tlb", NULL, MTX_SPIN);
/* Set boot_cpu_id if needed. */
if (boot_cpu_id == -1) {
boot_cpu_id = PCPU_GET(apic_id);
cpu_info[boot_cpu_id].cpu_bsp = 1;
} else
KASSERT(boot_cpu_id == PCPU_GET(apic_id),
("BSP's APIC ID doesn't match boot_cpu_id"));
cpu_apic_ids[0] = boot_cpu_id;
/* Start each Application Processor */
start_all_aps();
/* Setup the initial logical CPUs info. */
logical_cpus = logical_cpus_mask = 0;
if (cpu_feature & CPUID_HTT)
logical_cpus = (cpu_procinfo & CPUID_HTT_CORES) >> 16;
set_logical_apic_ids();
}
/*
* Print various information about the SMP system hardware and setup.
*/
void
cpu_mp_announce(void)
{
int i, x;
/* List CPUs */
printf(" cpu0 (BSP): APIC ID: %2d\n", boot_cpu_id);
for (i = 1, x = 0; x < MAXCPU; x++) {
if (cpu_info[x].cpu_present && !cpu_info[x].cpu_bsp) {
KASSERT(i < mp_ncpus,
("mp_ncpus and actual cpus are out of whack"));
printf(" cpu%d (AP): APIC ID: %2d\n", i++, x);
}
}
}
/*
* AP CPU's call this to initialize themselves.
*/
void
init_secondary(void)
{
struct pcpu *pc;
u_int64_t msr, cr0;
int cpu, gsel_tss;
/* Set by the startup code for us to use */
cpu = bootAP;
/* Init tss */
common_tss[cpu] = common_tss[0];
common_tss[cpu].tss_rsp0 = 0; /* not used until after switch */
gdt_segs[GPROC0_SEL].ssd_base = (long) &common_tss[cpu];
ssdtosyssd(&gdt_segs[GPROC0_SEL],
(struct system_segment_descriptor *)&gdt[GPROC0_SEL]);
lgdt(&r_gdt); /* does magic intra-segment return */
/* Get per-cpu data */
pc = &__pcpu[cpu];
/* prime data page for it to use */
pcpu_init(pc, cpu, sizeof(struct pcpu));
pc->pc_apic_id = cpu_apic_ids[cpu];
pc->pc_prvspace = pc;
pc->pc_curthread = 0;
pc->pc_tssp = &common_tss[cpu];
pc->pc_rsp0 = 0;
wrmsr(MSR_FSBASE, 0); /* User value */
wrmsr(MSR_GSBASE, (u_int64_t)pc);
wrmsr(MSR_KGSBASE, (u_int64_t)pc); /* XXX User value while we're in the kernel */
lidt(&r_idt);
gsel_tss = GSEL(GPROC0_SEL, SEL_KPL);
ltr(gsel_tss);
/*
* Set to a known state:
* Set by mpboot.s: CR0_PG, CR0_PE
* Set by cpu_setregs: CR0_NE, CR0_MP, CR0_TS, CR0_WP, CR0_AM
*/
cr0 = rcr0();
cr0 &= ~(CR0_CD | CR0_NW | CR0_EM);
load_cr0(cr0);
/* Set up the fast syscall stuff */
msr = rdmsr(MSR_EFER) | EFER_SCE;
wrmsr(MSR_EFER, msr);
wrmsr(MSR_LSTAR, (u_int64_t)IDTVEC(fast_syscall));
wrmsr(MSR_CSTAR, (u_int64_t)IDTVEC(fast_syscall32));
msr = ((u_int64_t)GSEL(GCODE_SEL, SEL_KPL) << 32) |
((u_int64_t)GSEL(GUCODE32_SEL, SEL_UPL) << 48);
wrmsr(MSR_STAR, msr);
wrmsr(MSR_SF_MASK, PSL_NT|PSL_T|PSL_I|PSL_C|PSL_D);
/* Disable local apic just to be sure. */
lapic_disable();
/* signal our startup to the BSP. */
mp_naps++;
/* Spin until the BSP releases the AP's. */
while (!aps_ready)
ia32_pause();
/* set up CPU registers and state */
cpu_setregs();
/* set up FPU state on the AP */
fpuinit();
/* set up SSE registers */
enable_sse();
/* A quick check from sanity claus */
if (PCPU_GET(apic_id) != lapic_id()) {
printf("SMP: cpuid = %d\n", PCPU_GET(cpuid));
printf("SMP: actual apic_id = %d\n", lapic_id());
printf("SMP: correct apic_id = %d\n", PCPU_GET(apic_id));
panic("cpuid mismatch! boom!!");
}
mtx_lock_spin(&ap_boot_mtx);
/* Init local apic for irq's */
lapic_setup();
/* Set memory range attributes for this CPU to match the BSP */
mem_range_AP_init();
smp_cpus++;
CTR1(KTR_SMP, "SMP: AP CPU #%d Launched", PCPU_GET(cpuid));
printf("SMP: AP CPU #%d Launched!\n", PCPU_GET(cpuid));
/* Determine if we are a logical CPU. */
if (logical_cpus > 1 && PCPU_GET(apic_id) % logical_cpus != 0)
logical_cpus_mask |= PCPU_GET(cpumask);
/* Build our map of 'other' CPUs. */
PCPU_SET(other_cpus, all_cpus & ~PCPU_GET(cpumask));
if (bootverbose)
lapic_dump("AP");
if (smp_cpus == mp_ncpus) {
/* enable IPI's, tlb shootdown, freezes etc */
atomic_store_rel_int(&smp_started, 1);
smp_active = 1; /* historic */
}
mtx_unlock_spin(&ap_boot_mtx);
/* wait until all the AP's are up */
while (smp_started == 0)
ia32_pause();
/* ok, now grab sched_lock and enter the scheduler */
mtx_lock_spin(&sched_lock);
binuptime(PCPU_PTR(switchtime));
PCPU_SET(switchticks, ticks);
cpu_throw(NULL, choosethread()); /* doesn't return */
panic("scheduler returned us to %s", __func__);
/* NOTREACHED */
}
/*******************************************************************
* local functions and data
*/
/*
* Set the APIC logical IDs.
*
* We want to cluster logical CPU's within the same APIC ID cluster.
* Since logical CPU's are aligned simply filling in the clusters in
* APIC ID order works fine. Note that this does not try to balance
* the number of CPU's in each cluster. (XXX?)
*/
static void
set_logical_apic_ids(void)
{
u_int apic_id, cluster, cluster_id;
/* Force us to allocate cluster 0 at the start. */
cluster = -1;
cluster_id = APIC_MAX_INTRACLUSTER_ID;
for (apic_id = 0; apic_id < MAXCPU; apic_id++) {
if (!cpu_info[apic_id].cpu_present)
continue;
if (cluster_id == APIC_MAX_INTRACLUSTER_ID) {
cluster = ioapic_next_logical_cluster();
cluster_id = 0;
} else
cluster_id++;
if (bootverbose)
printf("APIC ID: physical %u, logical %u:%u\n",
apic_id, cluster, cluster_id);
lapic_set_logical_id(apic_id, cluster, cluster_id);
}
}
/*
* start each AP in our list
*/
static int
start_all_aps(void)
{
u_char mpbiosreason;
u_int32_t mpbioswarmvec;
int apic_id, cpu, i;
u_int64_t *pt4, *pt3, *pt2;
mtx_init(&ap_boot_mtx, "ap boot", NULL, MTX_SPIN);
/* install the AP 1st level boot code */
pmap_kenter(boot_address + KERNBASE, boot_address);
bcopy(mptramp_start, (void *)((uintptr_t)boot_address + KERNBASE), bootMP_size);
/* Locate the page tables, they'll be below the trampoline */
pt4 = (u_int64_t *)(uintptr_t)(mptramp_pagetables + KERNBASE);
pt3 = pt4 + (PAGE_SIZE) / sizeof(u_int64_t);
pt2 = pt3 + (PAGE_SIZE) / sizeof(u_int64_t);
/* Create the initial 1GB replicated page tables */
for (i = 0; i < 512; i++) {
/* Each slot of the level 4 pages points to the same level 3 page */
pt4[i] = (u_int64_t)(uintptr_t)(mptramp_pagetables + PAGE_SIZE);
pt4[i] |= PG_V | PG_RW | PG_U;
/* Each slot of the level 3 pages points to the same level 2 page */
pt3[i] = (u_int64_t)(uintptr_t)(mptramp_pagetables + (2 * PAGE_SIZE));
pt3[i] |= PG_V | PG_RW | PG_U;
/* The level 2 page slots are mapped with 2MB pages for 1GB. */
pt2[i] = i * (2 * 1024 * 1024);
pt2[i] |= PG_V | PG_RW | PG_PS | PG_U;
}
/* save the current value of the warm-start vector */
mpbioswarmvec = *((u_int32_t *) WARMBOOT_OFF);
outb(CMOS_REG, BIOS_RESET);
mpbiosreason = inb(CMOS_DATA);
/* setup a vector to our boot code */
*((volatile u_short *) WARMBOOT_OFF) = WARMBOOT_TARGET;
*((volatile u_short *) WARMBOOT_SEG) = (boot_address >> 4);
outb(CMOS_REG, BIOS_RESET);
outb(CMOS_DATA, BIOS_WARM); /* 'warm-start' */
/* start each AP */
cpu = 0;
for (apic_id = 0; apic_id < MAXCPU; apic_id++) {
if (!cpu_info[apic_id].cpu_present ||
cpu_info[apic_id].cpu_bsp)
continue;
cpu++;
/* save APIC ID for this logical ID */
cpu_apic_ids[cpu] = apic_id;
/* allocate and set up an idle stack data page */
bootstacks[cpu] = (char *)kmem_alloc(kernel_map, KSTACK_PAGES * PAGE_SIZE);
bootSTK = (char *)bootstacks[cpu] + KSTACK_PAGES * PAGE_SIZE - 8;
bootAP = cpu;
/* attempt to start the Application Processor */
if (!start_ap(apic_id)) {
/* restore the warmstart vector */
*(u_int32_t *) WARMBOOT_OFF = mpbioswarmvec;
panic("AP #%d (PHY# %d) failed!", cpu, apic_id);
}
all_cpus |= (1 << cpu); /* record AP in CPU map */
}
/* build our map of 'other' CPUs */
PCPU_SET(other_cpus, all_cpus & ~PCPU_GET(cpumask));
/* restore the warmstart vector */
*(u_int32_t *) WARMBOOT_OFF = mpbioswarmvec;
outb(CMOS_REG, BIOS_RESET);
outb(CMOS_DATA, mpbiosreason);
/* number of APs actually started */
return mp_naps;
}
/*
* This function starts the AP (application processor) identified
* by the APIC ID 'physicalCpu'. It does quite a "song and dance"
* to accomplish this. This is necessary because of the nuances
* of the different hardware we might encounter. It isn't pretty,
* but it seems to work.
*/
static int
start_ap(int apic_id)
{
int vector, ms;
int cpus;
/* calculate the vector */
vector = (boot_address >> 12) & 0xff;
/* used as a watchpoint to signal AP startup */
cpus = mp_naps;
/*
* first we do an INIT/RESET IPI this INIT IPI might be run, reseting
* and running the target CPU. OR this INIT IPI might be latched (P5
* bug), CPU waiting for STARTUP IPI. OR this INIT IPI might be
* ignored.
*/
/* do an INIT IPI: assert RESET */
lapic_ipi_raw(APIC_DEST_DESTFLD | APIC_TRIGMOD_EDGE |
APIC_LEVEL_ASSERT | APIC_DESTMODE_PHY | APIC_DELMODE_INIT, apic_id);
/* wait for pending status end */
lapic_ipi_wait(-1);
/* do an INIT IPI: deassert RESET */
lapic_ipi_raw(APIC_DEST_ALLESELF | APIC_TRIGMOD_LEVEL |
APIC_LEVEL_DEASSERT | APIC_DESTMODE_PHY | APIC_DELMODE_INIT, 0);
/* wait for pending status end */
DELAY(10000); /* wait ~10mS */
lapic_ipi_wait(-1);
/*
* next we do a STARTUP IPI: the previous INIT IPI might still be
* latched, (P5 bug) this 1st STARTUP would then terminate
* immediately, and the previously started INIT IPI would continue. OR
* the previous INIT IPI has already run. and this STARTUP IPI will
* run. OR the previous INIT IPI was ignored. and this STARTUP IPI
* will run.
*/
/* do a STARTUP IPI */
lapic_ipi_raw(APIC_DEST_DESTFLD | APIC_TRIGMOD_EDGE |
APIC_LEVEL_DEASSERT | APIC_DESTMODE_PHY | APIC_DELMODE_STARTUP |
vector, apic_id);
lapic_ipi_wait(-1);
DELAY(200); /* wait ~200uS */
/*
* finally we do a 2nd STARTUP IPI: this 2nd STARTUP IPI should run IF
* the previous STARTUP IPI was cancelled by a latched INIT IPI. OR
* this STARTUP IPI will be ignored, as only ONE STARTUP IPI is
* recognized after hardware RESET or INIT IPI.
*/
lapic_ipi_raw(APIC_DEST_DESTFLD | APIC_TRIGMOD_EDGE |
APIC_LEVEL_DEASSERT | APIC_DESTMODE_PHY | APIC_DELMODE_STARTUP |
vector, apic_id);
lapic_ipi_wait(-1);
DELAY(200); /* wait ~200uS */
/* Wait up to 5 seconds for it to start. */
for (ms = 0; ms < 50; ms++) {
if (mp_naps > cpus)
return 1; /* return SUCCESS */
DELAY(100000);
}
return 0; /* return FAILURE */
}
/*
* Flush the TLB on all other CPU's
*/
static void
smp_tlb_shootdown(u_int vector, vm_offset_t addr1, vm_offset_t addr2)
{
u_int ncpu;
ncpu = mp_ncpus - 1; /* does not shootdown self */
if (ncpu < 1)
return; /* no other cpus */
mtx_assert(&smp_tlb_mtx, MA_OWNED);
smp_tlb_addr1 = addr1;
smp_tlb_addr2 = addr2;
atomic_store_rel_int(&smp_tlb_wait, 0);
ipi_all_but_self(vector);
while (smp_tlb_wait < ncpu)
ia32_pause();
}
/*
* This is about as magic as it gets. fortune(1) has got similar code
* for reversing bits in a word. Who thinks up this stuff??
*
* Yes, it does appear to be consistently faster than:
* while (i = ffs(m)) {
* m >>= i;
* bits++;
* }
* and
* while (lsb = (m & -m)) { // This is magic too
* m &= ~lsb; // or: m ^= lsb
* bits++;
* }
* Both of these latter forms do some very strange things on gcc-3.1 with
* -mcpu=pentiumpro and/or -march=pentiumpro and/or -O or -O2.
* There is probably an SSE or MMX popcnt instruction.
*
* I wonder if this should be in libkern?
*
* XXX Stop the presses! Another one:
* static __inline u_int32_t
* popcnt1(u_int32_t v)
* {
* v -= ((v >> 1) & 0x55555555);
* v = (v & 0x33333333) + ((v >> 2) & 0x33333333);
* v = (v + (v >> 4)) & 0x0F0F0F0F;
* return (v * 0x01010101) >> 24;
* }
* The downside is that it has a multiply. With a pentium3 with
* -mcpu=pentiumpro and -march=pentiumpro then gcc-3.1 will use
* an imull, and in that case it is faster. In most other cases
* it appears slightly slower.
*
* Another variant (also from fortune):
* #define BITCOUNT(x) (((BX_(x)+(BX_(x)>>4)) & 0x0F0F0F0F) % 255)
* #define BX_(x) ((x) - (((x)>>1)&0x77777777) \
* - (((x)>>2)&0x33333333) \
* - (((x)>>3)&0x11111111))
*/
static __inline u_int32_t
popcnt(u_int32_t m)
{
m = (m & 0x55555555) + ((m & 0xaaaaaaaa) >> 1);
m = (m & 0x33333333) + ((m & 0xcccccccc) >> 2);
m = (m & 0x0f0f0f0f) + ((m & 0xf0f0f0f0) >> 4);
m = (m & 0x00ff00ff) + ((m & 0xff00ff00) >> 8);
m = (m & 0x0000ffff) + ((m & 0xffff0000) >> 16);
return m;
}
static void
smp_targeted_tlb_shootdown(u_int mask, u_int vector, vm_offset_t addr1, vm_offset_t addr2)
{
int ncpu, othercpus;
othercpus = mp_ncpus - 1;
if (mask == (u_int)-1) {
ncpu = othercpus;
if (ncpu < 1)
return;
} else {
mask &= ~PCPU_GET(cpumask);
if (mask == 0)
return;
ncpu = popcnt(mask);
if (ncpu > othercpus) {
/* XXX this should be a panic offence */
printf("SMP: tlb shootdown to %d other cpus (only have %d)\n",
ncpu, othercpus);
ncpu = othercpus;
}
/* XXX should be a panic, implied by mask == 0 above */
if (ncpu < 1)
return;
}
mtx_assert(&smp_tlb_mtx, MA_OWNED);
smp_tlb_addr1 = addr1;
smp_tlb_addr2 = addr2;
atomic_store_rel_int(&smp_tlb_wait, 0);
if (mask == (u_int)-1)
ipi_all_but_self(vector);
else
ipi_selected(mask, vector);
while (smp_tlb_wait < ncpu)
ia32_pause();
}
void
smp_invltlb(void)
{
if (smp_started)
smp_tlb_shootdown(IPI_INVLTLB, 0, 0);
}
void
smp_invlpg(vm_offset_t addr)
{
if (smp_started)
smp_tlb_shootdown(IPI_INVLPG, addr, 0);
}
void
smp_invlpg_range(vm_offset_t addr1, vm_offset_t addr2)
{
if (smp_started)
smp_tlb_shootdown(IPI_INVLRNG, addr1, addr2);
}
void
smp_masked_invltlb(u_int mask)
{
if (smp_started)
smp_targeted_tlb_shootdown(mask, IPI_INVLTLB, 0, 0);
}
void
smp_masked_invlpg(u_int mask, vm_offset_t addr)
{
if (smp_started)
smp_targeted_tlb_shootdown(mask, IPI_INVLPG, addr, 0);
}
void
smp_masked_invlpg_range(u_int mask, vm_offset_t addr1, vm_offset_t addr2)
{
if (smp_started)
smp_targeted_tlb_shootdown(mask, IPI_INVLRNG, addr1, addr2);
}
/*
* For statclock, we send an IPI to all CPU's to have them call this
* function.
*/
void
forwarded_statclock(struct clockframe frame)
{
struct thread *td;
CTR0(KTR_SMP, "forwarded_statclock");
td = curthread;
td->td_intr_nesting_level++;
if (profprocs != 0)
profclock(&frame);
if (pscnt == psdiv)
statclock(&frame);
td->td_intr_nesting_level--;
}
void
forward_statclock(void)
{
int map;
CTR0(KTR_SMP, "forward_statclock");
if (!smp_started || cold || panicstr)
return;
map = PCPU_GET(other_cpus) & ~(stopped_cpus|hlt_cpus_mask);
if (map != 0)
ipi_selected(map, IPI_STATCLOCK);
}
/*
* For each hardclock(), we send an IPI to all other CPU's to have them
* execute this function. It would be nice to reduce contention on
* sched_lock if we could simply peek at the CPU to determine the user/kernel
* state and call hardclock_process() on the CPU receiving the clock interrupt
* and then just use a simple IPI to handle any ast's if needed.
*/
void
forwarded_hardclock(struct clockframe frame)
{
struct thread *td;
CTR0(KTR_SMP, "forwarded_hardclock");
td = curthread;
td->td_intr_nesting_level++;
hardclock_process(&frame);
td->td_intr_nesting_level--;
}
void
forward_hardclock(void)
{
u_int map;
CTR0(KTR_SMP, "forward_hardclock");
if (!smp_started || cold || panicstr)
return;
map = PCPU_GET(other_cpus) & ~(stopped_cpus|hlt_cpus_mask);
if (map != 0)
ipi_selected(map, IPI_HARDCLOCK);
}
/*
* send an IPI to a set of cpus.
*/
void
ipi_selected(u_int32_t cpus, u_int ipi)
{
int cpu;
CTR3(KTR_SMP, "%s: cpus: %x ipi: %x", __func__, cpus, ipi);
while ((cpu = ffs(cpus)) != 0) {
cpu--;
KASSERT(cpu_apic_ids[cpu] != -1,
("IPI to non-existent CPU %d", cpu));
lapic_ipi_vectored(ipi, cpu_apic_ids[cpu]);
cpus &= ~(1 << cpu);
}
}
/*
* send an IPI INTerrupt containing 'vector' to all CPUs, including myself
*/
void
ipi_all(u_int ipi)
{
CTR2(KTR_SMP, "%s: ipi: %x", __func__, ipi);
lapic_ipi_vectored(ipi, APIC_IPI_DEST_ALL);
}
/*
* send an IPI to all CPUs EXCEPT myself
*/
void
ipi_all_but_self(u_int ipi)
{
CTR2(KTR_SMP, "%s: ipi: %x", __func__, ipi);
lapic_ipi_vectored(ipi, APIC_IPI_DEST_OTHERS);
}
/*
* send an IPI to myself
*/
void
ipi_self(u_int ipi)
{
CTR2(KTR_SMP, "%s: ipi: %x", __func__, ipi);
lapic_ipi_vectored(ipi, APIC_IPI_DEST_SELF);
}
/*
* This is called once the rest of the system is up and running and we're
* ready to let the AP's out of the pen.
*/
static void
release_aps(void *dummy __unused)
{
if (mp_ncpus == 1)
return;
mtx_lock_spin(&sched_lock);
atomic_store_rel_int(&aps_ready, 1);
while (smp_started == 0)
ia32_pause();
mtx_unlock_spin(&sched_lock);
}
SYSINIT(start_aps, SI_SUB_SMP, SI_ORDER_FIRST, release_aps, NULL);
static int
sysctl_hlt_cpus(SYSCTL_HANDLER_ARGS)
{
u_int mask;
int error;
mask = hlt_cpus_mask;
error = sysctl_handle_int(oidp, &mask, 0, req);
if (error || !req->newptr)
return (error);
if (logical_cpus_mask != 0 &&
(mask & logical_cpus_mask) == logical_cpus_mask)
hlt_logical_cpus = 1;
else
hlt_logical_cpus = 0;
if ((mask & all_cpus) == all_cpus)
mask &= ~(1<<0);
hlt_cpus_mask = mask;
return (error);
}
SYSCTL_PROC(_machdep, OID_AUTO, hlt_cpus, CTLTYPE_INT|CTLFLAG_RW,
0, 0, sysctl_hlt_cpus, "IU",
"Bitmap of CPUs to halt. 101 (binary) will halt CPUs 0 and 2.");
static int
sysctl_hlt_logical_cpus(SYSCTL_HANDLER_ARGS)
{
int disable, error;
disable = hlt_logical_cpus;
error = sysctl_handle_int(oidp, &disable, 0, req);
if (error || !req->newptr)
return (error);
if (disable)
hlt_cpus_mask |= logical_cpus_mask;
else
hlt_cpus_mask &= ~logical_cpus_mask;
if ((hlt_cpus_mask & all_cpus) == all_cpus)
hlt_cpus_mask &= ~(1<<0);
hlt_logical_cpus = disable;
return (error);
}
static void
cpu_hlt_setup(void *dummy __unused)
{
if (logical_cpus_mask != 0) {
TUNABLE_INT_FETCH("machdep.hlt_logical_cpus",
&hlt_logical_cpus);
sysctl_ctx_init(&logical_cpu_clist);
SYSCTL_ADD_PROC(&logical_cpu_clist,
SYSCTL_STATIC_CHILDREN(_machdep), OID_AUTO,
"hlt_logical_cpus", CTLTYPE_INT|CTLFLAG_RW, 0, 0,
sysctl_hlt_logical_cpus, "IU", "");
SYSCTL_ADD_UINT(&logical_cpu_clist,
SYSCTL_STATIC_CHILDREN(_machdep), OID_AUTO,
"logical_cpus_mask", CTLTYPE_INT|CTLFLAG_RD,
&logical_cpus_mask, 0, "");
if (hlt_logical_cpus)
hlt_cpus_mask |= logical_cpus_mask;
}
}
SYSINIT(cpu_hlt, SI_SUB_SMP, SI_ORDER_ANY, cpu_hlt_setup, NULL);
int
mp_grab_cpu_hlt(void)
{
u_int mask = PCPU_GET(cpumask);
int retval;
retval = mask & hlt_cpus_mask;
while (mask & hlt_cpus_mask)
__asm __volatile("sti; hlt" : : : "memory");
return (retval);
}
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