9597 Want hypervisor API for FPU management

[unleashed.git] / usr / src / uts / i86pc / os / machdep.c

/*
 * CDDL HEADER START
 *
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License (the "License").
 * You may not use this file except in compliance with the License.
 *
 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
 * or http://www.opensolaris.org/os/licensing.
 * See the License for the specific language governing permissions
 * and limitations under the License.
 *
 * When distributing Covered Code, include this CDDL HEADER in each
 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
 * If applicable, add the following below this CDDL HEADER, with the
 * fields enclosed by brackets "[]" replaced with your own identifying
 * information: Portions Copyright [yyyy] [name of copyright owner]
 *
 * CDDL HEADER END
 */

/*
 * Copyright (c) 1992, 2010, Oracle and/or its affiliates. All rights reserved.
 * Copyright 2017, Joyent, Inc.
 */
/*
 * Copyright (c) 2010, Intel Corporation.
 * All rights reserved.
 */

#include <sys/types.h>
#include <sys/t_lock.h>
#include <sys/param.h>
#include <sys/segments.h>
#include <sys/sysmacros.h>
#include <sys/signal.h>
#include <sys/systm.h>
#include <sys/user.h>
#include <sys/mman.h>
#include <sys/vm.h>

#include <sys/disp.h>
#include <sys/class.h>

#include <sys/proc.h>
#include <sys/buf.h>
#include <sys/kmem.h>

#include <sys/reboot.h>
#include <sys/uadmin.h>
#include <sys/callb.h>

#include <sys/cred.h>
#include <sys/vnode.h>
#include <sys/file.h>

#include <sys/procfs.h>
#include <sys/acct.h>

#include <sys/vfs.h>
#include <sys/dnlc.h>
#include <sys/var.h>
#include <sys/cmn_err.h>
#include <sys/utsname.h>
#include <sys/debug.h>

#include <sys/dumphdr.h>
#include <sys/bootconf.h>
#include <sys/varargs.h>
#include <sys/promif.h>
#include <sys/modctl.h>

#include <sys/consdev.h>
#include <sys/frame.h>

#include <sys/sunddi.h>
#include <sys/ddidmareq.h>
#include <sys/psw.h>
#include <sys/regset.h>
#include <sys/privregs.h>
#include <sys/clock.h>
#include <sys/tss.h>
#include <sys/cpu.h>
#include <sys/stack.h>
#include <sys/trap.h>
#include <sys/pic.h>
#include <vm/hat.h>
#include <vm/anon.h>
#include <vm/as.h>
#include <vm/page.h>
#include <vm/seg.h>
#include <vm/seg_kmem.h>
#include <vm/seg_map.h>
#include <vm/seg_vn.h>
#include <vm/seg_kp.h>
#include <vm/hat_i86.h>
#include <sys/swap.h>
#include <sys/thread.h>
#include <sys/sysconf.h>
#include <sys/vm_machparam.h>
#include <sys/archsystm.h>
#include <sys/machsystm.h>
#include <sys/machlock.h>
#include <sys/x_call.h>
#include <sys/instance.h>

#include <sys/time.h>
#include <sys/smp_impldefs.h>
#include <sys/psm_types.h>
#include <sys/atomic.h>
#include <sys/panic.h>
#include <sys/cpuvar.h>
#include <sys/dtrace.h>
#include <sys/bl.h>
#include <sys/nvpair.h>
#include <sys/x86_archext.h>
#include <sys/pool_pset.h>
#include <sys/autoconf.h>
#include <sys/mem.h>
#include <sys/dumphdr.h>
#include <sys/compress.h>
#include <sys/cpu_module.h>
#if defined(__xpv)
#include <sys/hypervisor.h>
#include <sys/xpv_panic.h>
#endif

#include <sys/fastboot.h>
#include <sys/machelf.h>
#include <sys/kobj.h>
#include <sys/multiboot.h>

#ifdef  TRAPTRACE
#include <sys/traptrace.h>
#endif  /* TRAPTRACE */

#include <c2/audit.h>
#include <sys/clock_impl.h>

extern void audit_enterprom(int);
extern void audit_exitprom(int);

/*
 * Tunable to enable apix PSM; if set to 0, pcplusmp PSM will be used.
 */
int     apix_enable = 1;

int     apic_nvidia_io_max = 0; /* no. of NVIDIA i/o apics */

/*
 * Occassionally the kernel knows better whether to power-off or reboot.
 */
int force_shutdown_method = AD_UNKNOWN;

/*
 * The panicbuf array is used to record messages and state:
 */
char panicbuf[PANICBUFSIZE];

/*
 * Flags to control Dynamic Reconfiguration features.
 */
uint64_t plat_dr_options;

/*
 * Maximum physical address for memory DR operations.
 */
uint64_t plat_dr_physmax;

/*
 * maxphys - used during physio
 * klustsize - used for klustering by swapfs and specfs
 */
int maxphys = 56 * 1024;    /* XXX See vm_subr.c - max b_count in physio */
int klustsize = 56 * 1024;

caddr_t p0_va;          /* Virtual address for accessing physical page 0 */

/*
 * defined here, though unused on x86,
 * to make kstat_fr.c happy.
 */
int vac;

void debug_enter(char *);

extern void pm_cfb_check_and_powerup(void);
extern void pm_cfb_rele(void);

extern fastboot_info_t newkernel;

/*
 * Machine dependent code to reboot.
 * "mdep" is interpreted as a character pointer; if non-null, it is a pointer
 * to a string to be used as the argument string when rebooting.
 *
 * "invoke_cb" is a boolean. It is set to true when mdboot() can safely
 * invoke CB_CL_MDBOOT callbacks before shutting the system down, i.e. when
 * we are in a normal shutdown sequence (interrupts are not blocked, the
 * system is not panic'ing or being suspended).
 */
/*ARGSUSED*/
void
mdboot(int cmd, int fcn, char *mdep, boolean_t invoke_cb)
{
        processorid_t bootcpuid = 0;
        static int is_first_quiesce = 1;
        static int is_first_reset = 1;
        int reset_status = 0;
        static char fallback_str[] = "Falling back to regular reboot.\n";

        if (fcn == AD_FASTREBOOT && !newkernel.fi_valid)
                fcn = AD_BOOT;

        if (!panicstr) {
                kpreempt_disable();
                if (fcn == AD_FASTREBOOT) {
                        mutex_enter(&cpu_lock);
                        if (CPU_ACTIVE(cpu_get(bootcpuid))) {
                                affinity_set(bootcpuid);
                        }
                        mutex_exit(&cpu_lock);
                } else {
                        affinity_set(CPU_CURRENT);
                }
        }

        if (force_shutdown_method != AD_UNKNOWN)
                fcn = force_shutdown_method;

        /*
         * XXX - rconsvp is set to NULL to ensure that output messages
         * are sent to the underlying "hardware" device using the
         * monitor's printf routine since we are in the process of
         * either rebooting or halting the machine.
         */
        rconsvp = NULL;

        /*
         * Print the reboot message now, before pausing other cpus.
         * There is a race condition in the printing support that
         * can deadlock multiprocessor machines.
         */
        if (!(fcn == AD_HALT || fcn == AD_POWEROFF))
                prom_printf("rebooting...\n");

        if (IN_XPV_PANIC())
                reset();

        /*
         * We can't bring up the console from above lock level, so do it now
         */
        pm_cfb_check_and_powerup();

        /* make sure there are no more changes to the device tree */
        devtree_freeze();

        if (invoke_cb)
                (void) callb_execute_class(CB_CL_MDBOOT, NULL);

        /*
         * Clear any unresolved UEs from memory.
         */
        page_retire_mdboot();

#if defined(__xpv)
        /*
         * XXPV Should probably think some more about how we deal
         *      with panicing before it's really safe to panic.
         *      On hypervisors, we reboot very quickly..  Perhaps panic
         *      should only attempt to recover by rebooting if,
         *      say, we were able to mount the root filesystem,
         *      or if we successfully launched init(1m).
         */
        if (panicstr && proc_init == NULL)
                (void) HYPERVISOR_shutdown(SHUTDOWN_poweroff);
#endif
        /*
         * stop other cpus and raise our priority.  since there is only
         * one active cpu after this, and our priority will be too high
         * for us to be preempted, we're essentially single threaded
         * from here on out.
         */
        (void) spl6();
        if (!panicstr) {
                mutex_enter(&cpu_lock);
                pause_cpus(NULL, NULL);
                mutex_exit(&cpu_lock);
        }

        /*
         * If the system is panicking, the preloaded kernel is valid, and
         * fastreboot_onpanic has been set, and the system has been up for
         * longer than fastreboot_onpanic_uptime (default to 10 minutes),
         * choose Fast Reboot.
         */
        if (fcn == AD_BOOT && panicstr && newkernel.fi_valid &&
            fastreboot_onpanic &&
            (panic_lbolt - lbolt_at_boot) > fastreboot_onpanic_uptime) {
                fcn = AD_FASTREBOOT;
        }

        /*
         * Try to quiesce devices.
         */
        if (is_first_quiesce) {
                /*
                 * Clear is_first_quiesce before calling quiesce_devices()
                 * so that if quiesce_devices() causes panics, it will not
                 * be invoked again.
                 */
                is_first_quiesce = 0;

                quiesce_active = 1;
                quiesce_devices(ddi_root_node(), &reset_status);
                if (reset_status == -1) {
                        if (fcn == AD_FASTREBOOT && !force_fastreboot) {
                                prom_printf("Driver(s) not capable of fast "
                                    "reboot.\n");
                                prom_printf(fallback_str);
                                fastreboot_capable = 0;
                                fcn = AD_BOOT;
                        } else if (fcn != AD_FASTREBOOT)
                                fastreboot_capable = 0;
                }
                quiesce_active = 0;
        }

        /*
         * Try to reset devices. reset_leaves() should only be called
         * a) when there are no other threads that could be accessing devices,
         *    and
         * b) on a system that's not capable of fast reboot (fastreboot_capable
         *    being 0), or on a system where quiesce_devices() failed to
         *    complete (quiesce_active being 1).
         */
        if (is_first_reset && (!fastreboot_capable || quiesce_active)) {
                /*
                 * Clear is_first_reset before calling reset_devices()
                 * so that if reset_devices() causes panics, it will not
                 * be invoked again.
                 */
                is_first_reset = 0;
                reset_leaves();
        }

        /* Verify newkernel checksum */
        if (fastreboot_capable && fcn == AD_FASTREBOOT &&
            fastboot_cksum_verify(&newkernel) != 0) {
                fastreboot_capable = 0;
                prom_printf("Fast reboot: checksum failed for the new "
                    "kernel.\n");
                prom_printf(fallback_str);
        }

        (void) spl8();

        if (fastreboot_capable && fcn == AD_FASTREBOOT) {
                /*
                 * psm_shutdown is called within fast_reboot()
                 */
                fast_reboot();
        } else {
                (*psm_shutdownf)(cmd, fcn);

                if (fcn == AD_HALT || fcn == AD_POWEROFF)
                        halt((char *)NULL);
                else
                        prom_reboot("");
        }
        /*NOTREACHED*/
}

/* mdpreboot - may be called prior to mdboot while root fs still mounted */
/*ARGSUSED*/
void
mdpreboot(int cmd, int fcn, char *mdep)
{
        if (fcn == AD_FASTREBOOT && !fastreboot_capable) {
                fcn = AD_BOOT;
#ifdef  __xpv
                cmn_err(CE_WARN, "Fast reboot is not supported on xVM");
#else
                cmn_err(CE_WARN,
                    "Fast reboot is not supported on this platform%s",
                    fastreboot_nosup_message());
#endif
        }

        if (fcn == AD_FASTREBOOT) {
                fastboot_load_kernel(mdep);
                if (!newkernel.fi_valid)
                        fcn = AD_BOOT;
        }

        (*psm_preshutdownf)(cmd, fcn);
}

static void
stop_other_cpus(void)
{
        ulong_t s = clear_int_flag(); /* fast way to keep CPU from changing */
        cpuset_t xcset;

        CPUSET_ALL_BUT(xcset, CPU->cpu_id);
        xc_priority(0, 0, 0, CPUSET2BV(xcset), (xc_func_t)mach_cpu_halt);
        restore_int_flag(s);
}

/*
 *      Machine dependent abort sequence handling
 */
void
abort_sequence_enter(char *msg)
{
        if (abort_enable == 0) {
                if (AU_ZONE_AUDITING(GET_KCTX_GZ))
                        audit_enterprom(0);
                return;
        }
        if (AU_ZONE_AUDITING(GET_KCTX_GZ))
                audit_enterprom(1);
        debug_enter(msg);
        if (AU_ZONE_AUDITING(GET_KCTX_GZ))
                audit_exitprom(1);
}

/*
 * Enter debugger.  Called when the user types ctrl-alt-d or whenever
 * code wants to enter the debugger and possibly resume later.
 *
 * msg: message to print, possibly NULL.
 */
void
debug_enter(char *msg)
{
        if (dtrace_debugger_init != NULL)
                (*dtrace_debugger_init)();

        if (msg != NULL || (boothowto & RB_DEBUG))
                prom_printf("\n");

        if (msg != NULL)
                prom_printf("%s\n", msg);

        if (boothowto & RB_DEBUG)
                kmdb_enter();

        if (dtrace_debugger_fini != NULL)
                (*dtrace_debugger_fini)();
}

void
reset(void)
{
        extern  void acpi_reset_system();
#if !defined(__xpv)
        ushort_t *bios_memchk;

        /*
         * Can't use psm_map_phys or acpi_reset_system before the hat is
         * initialized.
         */
        if (khat_running) {
                bios_memchk = (ushort_t *)psm_map_phys(0x472,
                    sizeof (ushort_t), PROT_READ | PROT_WRITE);
                if (bios_memchk)
                        *bios_memchk = 0x1234;  /* bios memory check disable */

                if (options_dip != NULL &&
                    ddi_prop_exists(DDI_DEV_T_ANY, ddi_root_node(), 0,
                    "efi-systab")) {
                        if (bootops == NULL)
                                acpi_reset_system();
                        efi_reset();
                }

                /*
                 * The problem with using stubs is that we can call
                 * acpi_reset_system only after the kernel is up and running.
                 *
                 * We should create a global state to keep track of how far
                 * up the kernel is but for the time being we will depend on
                 * bootops. bootops cleared in startup_end().
                 */
                if (bootops == NULL)
                        acpi_reset_system();
        }

        pc_reset();
#else
        if (IN_XPV_PANIC()) {
                if (khat_running && bootops == NULL) {
                        acpi_reset_system();
                }

                pc_reset();
        }

        (void) HYPERVISOR_shutdown(SHUTDOWN_reboot);
        panic("HYPERVISOR_shutdown() failed");
#endif
        /*NOTREACHED*/
}

/*
 * Halt the machine and return to the monitor
 */
void
halt(char *s)
{
        stop_other_cpus();      /* send stop signal to other CPUs */
        if (s)
                prom_printf("(%s) \n", s);
        prom_exit_to_mon();
        /*NOTREACHED*/
}

/*
 * Initiate interrupt redistribution.
 */
void
i_ddi_intr_redist_all_cpus()
{
}

/*
 * XXX These probably ought to live somewhere else
 * XXX They are called from mem.c
 */

/*
 * Convert page frame number to an OBMEM page frame number
 * (i.e. put in the type bits -- zero for this implementation)
 */
pfn_t
impl_obmem_pfnum(pfn_t pf)
{
        return (pf);
}

#ifdef  NM_DEBUG
int nmi_test = 0;       /* checked in intentry.s during clock int */
int nmtest = -1;
nmfunc1(int arg, struct regs *rp)
{
        printf("nmi called with arg = %x, regs = %x\n", arg, rp);
        nmtest += 50;
        if (arg == nmtest) {
                printf("ip = %x\n", rp->r_pc);
                return (1);
        }
        return (0);
}

#endif

#include <sys/bootsvcs.h>

/* Hacked up initialization for initial kernel check out is HERE. */
/* The basic steps are: */
/*      kernel bootfuncs definition/initialization for KADB */
/*      kadb bootfuncs pointer initialization */
/*      putchar/getchar (interrupts disabled) */

/* kadb bootfuncs pointer initialization */

int
sysp_getchar()
{
        int i;
        ulong_t s;

        if (cons_polledio == NULL) {
                /* Uh oh */
                prom_printf("getchar called with no console\n");
                for (;;)
                        /* LOOP FOREVER */;
        }

        s = clear_int_flag();
        i = cons_polledio->cons_polledio_getchar(
            cons_polledio->cons_polledio_argument);
        restore_int_flag(s);
        return (i);
}

void
sysp_putchar(int c)
{
        ulong_t s;

        /*
         * We have no alternative but to drop the output on the floor.
         */
        if (cons_polledio == NULL ||
            cons_polledio->cons_polledio_putchar == NULL)
                return;

        s = clear_int_flag();
        cons_polledio->cons_polledio_putchar(
            cons_polledio->cons_polledio_argument, c);
        restore_int_flag(s);
}

int
sysp_ischar()
{
        int i;
        ulong_t s;

        if (cons_polledio == NULL ||
            cons_polledio->cons_polledio_ischar == NULL)
                return (0);

        s = clear_int_flag();
        i = cons_polledio->cons_polledio_ischar(
            cons_polledio->cons_polledio_argument);
        restore_int_flag(s);
        return (i);
}

int
goany(void)
{
        prom_printf("Type any key to continue ");
        (void) prom_getchar();
        prom_printf("\n");
        return (1);
}

static struct boot_syscalls kern_sysp = {
        sysp_getchar,   /*      unchar  (*getchar)();   7  */
        sysp_putchar,   /*      int     (*putchar)();   8  */
        sysp_ischar,    /*      int     (*ischar)();    9  */
};

#if defined(__xpv)
int using_kern_polledio;
#endif

void
kadb_uses_kernel()
{
        /*
         * This routine is now totally misnamed, since it does not in fact
         * control kadb's I/O; it only controls the kernel's prom_* I/O.
         */
        sysp = &kern_sysp;
#if defined(__xpv)
        using_kern_polledio = 1;
#endif
}

/*
 *      the interface to the outside world
 */

/*
 * poll_port -- wait for a register to achieve a
 *              specific state.  Arguments are a mask of bits we care about,
 *              and two sub-masks.  To return normally, all the bits in the
 *              first sub-mask must be ON, all the bits in the second sub-
 *              mask must be OFF.  If about seconds pass without the register
 *              achieving the desired bit configuration, we return 1, else
 *              0.
 */
int
poll_port(ushort_t port, ushort_t mask, ushort_t onbits, ushort_t offbits)
{
        int i;
        ushort_t maskval;

        for (i = 500000; i; i--) {
                maskval = inb(port) & mask;
                if (((maskval & onbits) == onbits) &&
                    ((maskval & offbits) == 0))
                        return (0);
                drv_usecwait(10);
        }
        return (1);
}

/*
 * set_idle_cpu is called from idle() when a CPU becomes idle.
 */
/*LINTED: static unused */
static uint_t last_idle_cpu;

/*ARGSUSED*/
void
set_idle_cpu(int cpun)
{
        last_idle_cpu = cpun;
        (*psm_set_idle_cpuf)(cpun);
}

/*
 * unset_idle_cpu is called from idle() when a CPU is no longer idle.
 */
/*ARGSUSED*/
void
unset_idle_cpu(int cpun)
{
        (*psm_unset_idle_cpuf)(cpun);
}

/*
 * This routine is almost correct now, but not quite.  It still needs the
 * equivalent concept of "hres_last_tick", just like on the sparc side.
 * The idea is to take a snapshot of the hi-res timer while doing the
 * hrestime_adj updates under hres_lock in locore, so that the small
 * interval between interrupt assertion and interrupt processing is
 * accounted for correctly.  Once we have this, the code below should
 * be modified to subtract off hres_last_tick rather than hrtime_base.
 *
 * I'd have done this myself, but I don't have source to all of the
 * vendor-specific hi-res timer routines (grrr...).  The generic hook I
 * need is something like "gethrtime_unlocked()", which would be just like
 * gethrtime() but would assume that you're already holding CLOCK_LOCK().
 * This is what the GET_HRTIME() macro is for on sparc (although it also
 * serves the function of making time available without a function call
 * so you don't take a register window overflow while traps are disabled).
 */
void
pc_gethrestime(timestruc_t *tp)
{
        int lock_prev;
        timestruc_t now;
        int nslt;               /* nsec since last tick */
        int adj;                /* amount of adjustment to apply */

loop:
        lock_prev = hres_lock;
        now = hrestime;
        nslt = (int)(gethrtime() - hres_last_tick);
        if (nslt < 0) {
                /*
                 * nslt < 0 means a tick came between sampling
                 * gethrtime() and hres_last_tick; restart the loop
                 */

                goto loop;
        }
        now.tv_nsec += nslt;
        if (hrestime_adj != 0) {
                if (hrestime_adj > 0) {
                        adj = (nslt >> ADJ_SHIFT);
                        if (adj > hrestime_adj)
                                adj = (int)hrestime_adj;
                } else {
                        adj = -(nslt >> ADJ_SHIFT);
                        if (adj < hrestime_adj)
                                adj = (int)hrestime_adj;
                }
                now.tv_nsec += adj;
        }
        while ((unsigned long)now.tv_nsec >= NANOSEC) {

                /*
                 * We might have a large adjustment or have been in the
                 * debugger for a long time; take care of (at most) four
                 * of those missed seconds (tv_nsec is 32 bits, so
                 * anything >4s will be wrapping around).  However,
                 * anything more than 2 seconds out of sync will trigger
                 * timedelta from clock() to go correct the time anyway,
                 * so do what we can, and let the big crowbar do the
                 * rest.  A similar correction while loop exists inside
                 * hres_tick(); in all cases we'd like tv_nsec to
                 * satisfy 0 <= tv_nsec < NANOSEC to avoid confusing
                 * user processes, but if tv_sec's a little behind for a
                 * little while, that's OK; time still monotonically
                 * increases.
                 */

                now.tv_nsec -= NANOSEC;
                now.tv_sec++;
        }
        if ((hres_lock & ~1) != lock_prev)
                goto loop;

        *tp = now;
}

void
gethrestime_lasttick(timespec_t *tp)
{
        int s;

        s = hr_clock_lock();
        *tp = hrestime;
        hr_clock_unlock(s);
}

time_t
gethrestime_sec(void)
{
        timestruc_t now;

        gethrestime(&now);
        return (now.tv_sec);
}

/*
 * Initialize a kernel thread's stack
 */

caddr_t
thread_stk_init(caddr_t stk)
{
        ASSERT(((uintptr_t)stk & (STACK_ALIGN - 1)) == 0);
        return (stk - SA(MINFRAME));
}

/*
 * Initialize lwp's kernel stack.
 */

#ifdef TRAPTRACE
/*
 * There's a tricky interdependency here between use of sysenter and
 * TRAPTRACE which needs recording to avoid future confusion (this is
 * about the third time I've re-figured this out ..)
 *
 * Here's how debugging lcall works with TRAPTRACE.
 *
 * 1 We're in userland with a breakpoint on the lcall instruction.
 * 2 We execute the instruction - the instruction pushes the userland
 *   %ss, %esp, %efl, %cs, %eip on the stack and zips into the kernel
 *   via the call gate.
 * 3 The hardware raises a debug trap in kernel mode, the hardware
 *   pushes %efl, %cs, %eip and gets to dbgtrap via the idt.
 * 4 dbgtrap pushes the error code and trapno and calls cmntrap
 * 5 cmntrap finishes building a trap frame
 * 6 The TRACE_REGS macros in cmntrap copy a REGSIZE worth chunk
 *   off the stack into the traptrace buffer.
 *
 * This means that the traptrace buffer contains the wrong values in
 * %esp and %ss, but everything else in there is correct.
 *
 * Here's how debugging sysenter works with TRAPTRACE.
 *
 * a We're in userland with a breakpoint on the sysenter instruction.
 * b We execute the instruction - the instruction pushes -nothing-
 *   on the stack, but sets %cs, %eip, %ss, %esp to prearranged
 *   values to take us to sys_sysenter, at the top of the lwp's
 *   stack.
 * c goto 3
 *
 * At this point, because we got into the kernel without the requisite
 * five pushes on the stack, if we didn't make extra room, we'd
 * end up with the TRACE_REGS macro fetching the saved %ss and %esp
 * values from negative (unmapped) stack addresses -- which really bites.
 * That's why we do the '-= 8' below.
 *
 * XXX  Note that reading "up" lwp0's stack works because t0 is declared
 *      right next to t0stack in locore.s
 */
#endif

caddr_t
lwp_stk_init(klwp_t *lwp, caddr_t stk)
{
        caddr_t oldstk;
        struct pcb *pcb = &lwp->lwp_pcb;

        oldstk = stk;
        stk -= SA(sizeof (struct regs) + SA(MINFRAME));
#ifdef TRAPTRACE
        stk -= 2 * sizeof (greg_t); /* space for phony %ss:%sp (see above) */
#endif
        stk = (caddr_t)((uintptr_t)stk & ~(STACK_ALIGN - 1ul));
        bzero(stk, oldstk - stk);
        lwp->lwp_regs = (void *)(stk + SA(MINFRAME));

        /*
         * Arrange that the virtualized %fs and %gs GDT descriptors
         * have a well-defined initial state (present, ring 3
         * and of type data).
         */
#if defined(__amd64)
        if (lwp_getdatamodel(lwp) == DATAMODEL_NATIVE)
                pcb->pcb_fsdesc = pcb->pcb_gsdesc = zero_udesc;
        else
                pcb->pcb_fsdesc = pcb->pcb_gsdesc = zero_u32desc;
#elif defined(__i386)
        pcb->pcb_fsdesc = pcb->pcb_gsdesc = zero_udesc;
#endif  /* __i386 */
        lwp_installctx(lwp);
        return (stk);
}

/*
 * Use this opportunity to free any dynamically allocated fp storage.
 */
void
lwp_stk_fini(klwp_t *lwp)
{
        fp_lwp_cleanup(lwp);
}

void
lwp_fp_init(klwp_t *lwp)
{
        fp_lwp_init(lwp);
}

/*
 * If we're not the panic CPU, we wait in panic_idle for reboot.
 */
void
panic_idle(void)
{
        splx(ipltospl(CLOCK_LEVEL));
        (void) setjmp(&curthread->t_pcb);

        dumpsys_helper();

#ifndef __xpv
        for (;;)
                i86_halt();
#else
        for (;;)
                ;
#endif
}

/*
 * Stop the other CPUs by cross-calling them and forcing them to enter
 * the panic_idle() loop above.
 */
/*ARGSUSED*/
void
panic_stopcpus(cpu_t *cp, kthread_t *t, int spl)
{
        processorid_t i;
        cpuset_t xcset;

        /*
         * In the case of a Xen panic, the hypervisor has already stopped
         * all of the CPUs.
         */
        if (!IN_XPV_PANIC()) {
                (void) splzs();

                CPUSET_ALL_BUT(xcset, cp->cpu_id);
                xc_priority(0, 0, 0, CPUSET2BV(xcset), (xc_func_t)panic_idle);
        }

        for (i = 0; i < NCPU; i++) {
                if (i != cp->cpu_id && cpu[i] != NULL &&
                    (cpu[i]->cpu_flags & CPU_EXISTS))
                        cpu[i]->cpu_flags |= CPU_QUIESCED;
        }
}

/*
 * Platform callback following each entry to panicsys().
 */
/*ARGSUSED*/
void
panic_enter_hw(int spl)
{
        /* Nothing to do here */
}

/*
 * Platform-specific code to execute after panicstr is set: we invoke
 * the PSM entry point to indicate that a panic has occurred.
 */
/*ARGSUSED*/
void
panic_quiesce_hw(panic_data_t *pdp)
{
        psm_notifyf(PSM_PANIC_ENTER);

        cmi_panic_callback();

#ifdef  TRAPTRACE
        /*
         * Turn off TRAPTRACE
         */
        TRAPTRACE_FREEZE;
#endif  /* TRAPTRACE */
}

/*
 * Platform callback prior to writing crash dump.
 */
/*ARGSUSED*/
void
panic_dump_hw(int spl)
{
        /* Nothing to do here */
}

void *
plat_traceback(void *fpreg)
{
#ifdef __xpv
        if (IN_XPV_PANIC())
                return (xpv_traceback(fpreg));
#endif
        return (fpreg);
}

/*ARGSUSED*/
void
plat_tod_fault(enum tod_fault_type tod_bad)
{}

/*ARGSUSED*/
int
blacklist(int cmd, const char *scheme, nvlist_t *fmri, const char *class)
{
        return (ENOTSUP);
}

/*
 * The underlying console output routines are protected by raising IPL in case
 * we are still calling into the early boot services.  Once we start calling
 * the kernel console emulator, it will disable interrupts completely during
 * character rendering (see sysp_putchar, for example).  Refer to the comments
 * and code in common/os/console.c for more information on these callbacks.
 */
/*ARGSUSED*/
int
console_enter(int busy)
{
        return (splzs());
}

/*ARGSUSED*/
void
console_exit(int busy, int spl)
{
        splx(spl);
}

/*
 * Allocate a region of virtual address space, unmapped.
 * Stubbed out except on sparc, at least for now.
 */
/*ARGSUSED*/
void *
boot_virt_alloc(void *addr, size_t size)
{
        return (addr);
}

volatile unsigned long  tenmicrodata;

void
tenmicrosec(void)
{
        extern int gethrtime_hires;

        if (gethrtime_hires) {
                hrtime_t start, end;
                start = end =  gethrtime();
                while ((end - start) < (10 * (NANOSEC / MICROSEC))) {
                        SMT_PAUSE();
                        end = gethrtime();
                }
        } else {
#if defined(__xpv)
                hrtime_t newtime;

                newtime = xpv_gethrtime() + 10000; /* now + 10 us */
                while (xpv_gethrtime() < newtime)
                        SMT_PAUSE();
#else   /* __xpv */
                int i;

                /*
                 * Artificial loop to induce delay.
                 */
                for (i = 0; i < microdata; i++)
                        tenmicrodata = microdata;
#endif  /* __xpv */
        }
}

/*
 * get_cpu_mstate() is passed an array of timestamps, NCMSTATES
 * long, and it fills in the array with the time spent on cpu in
 * each of the mstates, where time is returned in nsec.
 *
 * No guarantee is made that the returned values in times[] will
 * monotonically increase on sequential calls, although this will
 * be true in the long run. Any such guarantee must be handled by
 * the caller, if needed. This can happen if we fail to account
 * for elapsed time due to a generation counter conflict, yet we
 * did account for it on a prior call (see below).
 *
 * The complication is that the cpu in question may be updating
 * its microstate at the same time that we are reading it.
 * Because the microstate is only updated when the CPU's state
 * changes, the values in cpu_intracct[] can be indefinitely out
 * of date. To determine true current values, it is necessary to
 * compare the current time with cpu_mstate_start, and add the
 * difference to times[cpu_mstate].
 *
 * This can be a problem if those values are changing out from
 * under us. Because the code path in new_cpu_mstate() is
 * performance critical, we have not added a lock to it. Instead,
 * we have added a generation counter. Before beginning
 * modifications, the counter is set to 0. After modifications,
 * it is set to the old value plus one.
 *
 * get_cpu_mstate() will not consider the values of cpu_mstate
 * and cpu_mstate_start to be usable unless the value of
 * cpu_mstate_gen is both non-zero and unchanged, both before and
 * after reading the mstate information. Note that we must
 * protect against out-of-order loads around accesses to the
 * generation counter. Also, this is a best effort approach in
 * that we do not retry should the counter be found to have
 * changed.
 *
 * cpu_intracct[] is used to identify time spent in each CPU
 * mstate while handling interrupts. Such time should be reported
 * against system time, and so is subtracted out from its
 * corresponding cpu_acct[] time and added to
 * cpu_acct[CMS_SYSTEM].
 */

void
get_cpu_mstate(cpu_t *cpu, hrtime_t *times)
{
        int i;
        hrtime_t now, start;
        uint16_t gen;
        uint16_t state;
        hrtime_t intracct[NCMSTATES];

        /*
         * Load all volatile state under the protection of membar.
         * cpu_acct[cpu_mstate] must be loaded to avoid double counting
         * of (now - cpu_mstate_start) by a change in CPU mstate that
         * arrives after we make our last check of cpu_mstate_gen.
         */

        now = gethrtime_unscaled();
        gen = cpu->cpu_mstate_gen;

        membar_consumer();      /* guarantee load ordering */
        start = cpu->cpu_mstate_start;
        state = cpu->cpu_mstate;
        for (i = 0; i < NCMSTATES; i++) {
                intracct[i] = cpu->cpu_intracct[i];
                times[i] = cpu->cpu_acct[i];
        }
        membar_consumer();      /* guarantee load ordering */

        if (gen != 0 && gen == cpu->cpu_mstate_gen && now > start)
                times[state] += now - start;

        for (i = 0; i < NCMSTATES; i++) {
                if (i == CMS_SYSTEM)
                        continue;
                times[i] -= intracct[i];
                if (times[i] < 0) {
                        intracct[i] += times[i];
                        times[i] = 0;
                }
                times[CMS_SYSTEM] += intracct[i];
                scalehrtime(&times[i]);
        }
        scalehrtime(&times[CMS_SYSTEM]);
}

/*
 * This is a version of the rdmsr instruction that allows
 * an error code to be returned in the case of failure.
 */
int
checked_rdmsr(uint_t msr, uint64_t *value)
{
        if (!is_x86_feature(x86_featureset, X86FSET_MSR))
                return (ENOTSUP);
        *value = rdmsr(msr);
        return (0);
}

/*
 * This is a version of the wrmsr instruction that allows
 * an error code to be returned in the case of failure.
 */
int
checked_wrmsr(uint_t msr, uint64_t value)
{
        if (!is_x86_feature(x86_featureset, X86FSET_MSR))
                return (ENOTSUP);
        wrmsr(msr, value);
        return (0);
}

/*
 * The mem driver's usual method of using hat_devload() to establish a
 * temporary mapping will not work for foreign pages mapped into this
 * domain or for the special hypervisor-provided pages.  For the foreign
 * pages, we often don't know which domain owns them, so we can't ask the
 * hypervisor to set up a new mapping.  For the other pages, we don't have
 * a pfn, so we can't create a new PTE.  For these special cases, we do a
 * direct uiomove() from the existing kernel virtual address.
 */
/*ARGSUSED*/
int
plat_mem_do_mmio(struct uio *uio, enum uio_rw rw)
{
#if defined(__xpv)
        void *va = (void *)(uintptr_t)uio->uio_loffset;
        off_t pageoff = uio->uio_loffset & PAGEOFFSET;
        size_t nbytes = MIN((size_t)(PAGESIZE - pageoff),
            (size_t)uio->uio_iov->iov_len);

        if ((rw == UIO_READ &&
            (va == HYPERVISOR_shared_info || va == xen_info)) ||
            (pfn_is_foreign(hat_getpfnum(kas.a_hat, va))))
                return (uiomove(va, nbytes, rw, uio));
#endif
        return (ENOTSUP);
}

pgcnt_t
num_phys_pages()
{
        pgcnt_t npages = 0;
        struct memlist *mp;

#if defined(__xpv)
        if (DOMAIN_IS_INITDOMAIN(xen_info))
                return (xpv_nr_phys_pages());
#endif /* __xpv */

        for (mp = phys_install; mp != NULL; mp = mp->ml_next)
                npages += mp->ml_size >> PAGESHIFT;

        return (npages);
}

/* cpu threshold for compressed dumps */
#ifdef _LP64
uint_t dump_plat_mincpu_default = DUMP_PLAT_X86_64_MINCPU;
#else
uint_t dump_plat_mincpu_default = DUMP_PLAT_X86_32_MINCPU;
#endif

int
dump_plat_addr()
{
#ifdef __xpv
        pfn_t pfn = mmu_btop(xen_info->shared_info) | PFN_IS_FOREIGN_MFN;
        mem_vtop_t mem_vtop;
        int cnt;

        /*
         * On the hypervisor, we want to dump the page with shared_info on it.
         */
        if (!IN_XPV_PANIC()) {
                mem_vtop.m_as = &kas;
                mem_vtop.m_va = HYPERVISOR_shared_info;
                mem_vtop.m_pfn = pfn;
                dumpvp_write(&mem_vtop, sizeof (mem_vtop_t));
                cnt = 1;
        } else {
                cnt = dump_xpv_addr();
        }
        return (cnt);
#else
        return (0);
#endif
}

void
dump_plat_pfn()
{
#ifdef __xpv
        pfn_t pfn = mmu_btop(xen_info->shared_info) | PFN_IS_FOREIGN_MFN;

        if (!IN_XPV_PANIC())
                dumpvp_write(&pfn, sizeof (pfn));
        else
                dump_xpv_pfn();
#endif
}

/*ARGSUSED*/
int
dump_plat_data(void *dump_cbuf)
{
#ifdef __xpv
        uint32_t csize;
        int cnt;

        if (!IN_XPV_PANIC()) {
                csize = (uint32_t)compress(HYPERVISOR_shared_info, dump_cbuf,
                    PAGESIZE);
                dumpvp_write(&csize, sizeof (uint32_t));
                dumpvp_write(dump_cbuf, csize);
                cnt = 1;
        } else {
                cnt = dump_xpv_data(dump_cbuf);
        }
        return (cnt);
#else
        return (0);
#endif
}

/*
 * Calculates a linear address, given the CS selector and PC values
 * by looking up the %cs selector process's LDT or the CPU's GDT.
 * proc->p_ldtlock must be held across this call.
 */
int
linear_pc(struct regs *rp, proc_t *p, caddr_t *linearp)
{
        user_desc_t     *descrp;
        caddr_t         baseaddr;
        uint16_t        idx = SELTOIDX(rp->r_cs);

        ASSERT(rp->r_cs <= 0xFFFF);
        ASSERT(MUTEX_HELD(&p->p_ldtlock));

        if (SELISLDT(rp->r_cs)) {
                /*
                 * Currently 64 bit processes cannot have private LDTs.
                 */
                ASSERT(p->p_model != DATAMODEL_LP64);

                if (p->p_ldt == NULL)
                        return (-1);

                descrp = &p->p_ldt[idx];
                baseaddr = (caddr_t)(uintptr_t)USEGD_GETBASE(descrp);

                /*
                 * Calculate the linear address (wraparound is not only ok,
                 * it's expected behavior).  The cast to uint32_t is because
                 * LDT selectors are only allowed in 32-bit processes.
                 */
                *linearp = (caddr_t)(uintptr_t)(uint32_t)((uintptr_t)baseaddr +
                    rp->r_pc);
        } else {
#ifdef DEBUG
                descrp = &CPU->cpu_gdt[idx];
                baseaddr = (caddr_t)(uintptr_t)USEGD_GETBASE(descrp);
                /* GDT-based descriptors' base addresses should always be 0 */
                ASSERT(baseaddr == 0);
#endif
                *linearp = (caddr_t)(uintptr_t)rp->r_pc;
        }

        return (0);
}

/*
 * The implementation of dtrace_linear_pc is similar to the that of
 * linear_pc, above, but here we acquire p_ldtlock before accessing
 * p_ldt.  This implementation is used by the pid provider; we prefix
 * it with "dtrace_" to avoid inducing spurious tracing events.
 */
int
dtrace_linear_pc(struct regs *rp, proc_t *p, caddr_t *linearp)
{
        user_desc_t     *descrp;
        caddr_t         baseaddr;
        uint16_t        idx = SELTOIDX(rp->r_cs);

        ASSERT(rp->r_cs <= 0xFFFF);

        if (SELISLDT(rp->r_cs)) {
                /*
                 * Currently 64 bit processes cannot have private LDTs.
                 */
                ASSERT(p->p_model != DATAMODEL_LP64);

                mutex_enter(&p->p_ldtlock);
                if (p->p_ldt == NULL) {
                        mutex_exit(&p->p_ldtlock);
                        return (-1);
                }
                descrp = &p->p_ldt[idx];
                baseaddr = (caddr_t)(uintptr_t)USEGD_GETBASE(descrp);
                mutex_exit(&p->p_ldtlock);

                /*
                 * Calculate the linear address (wraparound is not only ok,
                 * it's expected behavior).  The cast to uint32_t is because
                 * LDT selectors are only allowed in 32-bit processes.
                 */
                *linearp = (caddr_t)(uintptr_t)(uint32_t)((uintptr_t)baseaddr +
                    rp->r_pc);
        } else {
#ifdef DEBUG
                descrp = &CPU->cpu_gdt[idx];
                baseaddr = (caddr_t)(uintptr_t)USEGD_GETBASE(descrp);
                /* GDT-based descriptors' base addresses should always be 0 */
                ASSERT(baseaddr == 0);
#endif
                *linearp = (caddr_t)(uintptr_t)rp->r_pc;
        }

        return (0);
}

/*
 * We need to post a soft interrupt to reprogram the lbolt cyclic when
 * switching from event to cyclic driven lbolt. The following code adds
 * and posts the softint for x86.
 */
static ddi_softint_hdl_impl_t lbolt_softint_hdl =
        {0, NULL, NULL, NULL, 0, NULL, NULL, NULL};

void
lbolt_softint_add(void)
{
        (void) add_avsoftintr((void *)&lbolt_softint_hdl, LOCK_LEVEL,
            (avfunc)lbolt_ev_to_cyclic, "lbolt_ev_to_cyclic", NULL, NULL);
}

void
lbolt_softint_post(void)
{
        (*setsoftint)(CBE_LOCK_PIL, lbolt_softint_hdl.ih_pending);
}

boolean_t
plat_dr_check_capability(uint64_t features)
{
        return ((plat_dr_options & features) == features);
}

boolean_t
plat_dr_support_cpu(void)
{
        return (plat_dr_options & PLAT_DR_FEATURE_CPU);
}

boolean_t
plat_dr_support_memory(void)
{
        return (plat_dr_options & PLAT_DR_FEATURE_MEMORY);
}

void
plat_dr_enable_capability(uint64_t features)
{
        atomic_or_64(&plat_dr_options, features);
}

void
plat_dr_disable_capability(uint64_t features)
{
        atomic_and_64(&plat_dr_options, ~features);
}