src/pkg/runtime/os

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This source file includes following definitions.
getncpu
runtime·semacreate
runtime·semasleep
runtime·semawakeup
runtime·newosproc
runtime·osinit
runtime·get_random_data
runtime·goenvs
runtime·mpreinit
runtime·minit
runtime·unminit
runtime·sigpanic
runtime·memlimit
runtime·setsig
runtime·getsig
runtime·signalstack
runtime·unblocksignals
// Copyright 2011 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.

#include "runtime.h"
#include "defs_GOOS_GOARCH.h"
#include "os_GOOS.h"
#include "signal_unix.h"
#include "stack.h"
#include "../../cmd/ld/textflag.h"

enum
{
        ESRCH = 3,
        ENOTSUP = 91,

        // From NetBSD's <sys/time.h>
        CLOCK_REALTIME = 0,
        CLOCK_VIRTUAL = 1,
        CLOCK_PROF = 2,
        CLOCK_MONOTONIC = 3
};

extern SigTab runtime·sigtab[];

static Sigset sigset_none;
static Sigset sigset_all = { ~(uint32)0, ~(uint32)0, ~(uint32)0, ~(uint32)0, };

extern void runtime·getcontext(UcontextT *context);
extern int32 runtime·lwp_create(UcontextT *context, uintptr flags, void *lwpid);
extern void runtime·lwp_mcontext_init(void *mc, void *stack, M *mp, G *gp, void (*fn)(void));
extern int32 runtime·lwp_park(Timespec *abstime, int32 unpark, void *hint, void *unparkhint);
extern int32 runtime·lwp_unpark(int32 lwp, void *hint);
extern int32 runtime·lwp_self(void);

// From NetBSD's <sys/sysctl.h>
#define CTL_HW  6
#define HW_NCPU 3

static int32
getncpu(void)
{
        uint32 mib[2];
        uint32 out;
        int32 ret;
        uintptr nout;

        // Fetch hw.ncpu via sysctl.
        mib[0] = CTL_HW;
        mib[1] = HW_NCPU;
        nout = sizeof out;
        out = 0;
        ret = runtime·sysctl(mib, 2, (byte*)&out, &nout, nil, 0);
        if(ret >= 0)
                return out;
        else
                return 1;
}

uintptr
runtime·semacreate(void)
{
        return 1;
}

#pragma textflag NOSPLIT
int32
runtime·semasleep(int64 ns)
{
        Timespec ts;

        // spin-mutex lock
        while(runtime·xchg(&m->waitsemalock, 1))
                runtime·osyield();

        for(;;) {
                // lock held
                if(m->waitsemacount == 0) {
                        // sleep until semaphore != 0 or timeout.
                        // thrsleep unlocks m->waitsemalock.
                        if(ns < 0) {
                                // TODO(jsing) - potential deadlock!
                                //
                                // There is a potential deadlock here since we
                                // have to release the waitsemalock mutex
                                // before we call lwp_park() to suspend the
                                // thread. This allows another thread to
                                // release the lock and call lwp_unpark()
                                // before the thread is actually suspended.
                                // If this occurs the current thread will end
                                // up sleeping indefinitely. Unfortunately
                                // the NetBSD kernel does not appear to provide
                                // a mechanism for unlocking the userspace
                                // mutex once the thread is actually parked.
                                runtime·atomicstore(&m->waitsemalock, 0);
                                runtime·lwp_park(nil, 0, &m->waitsemacount, nil);
                        } else {
                                ns = ns + runtime·nanotime();
                                // NOTE: tv_nsec is int64 on amd64, so this assumes a little-endian system.
                                ts.tv_nsec = 0;
                                ts.tv_sec = runtime·timediv(ns, 1000000000, (int32*)&ts.tv_nsec);
                                // TODO(jsing) - potential deadlock!
                                // See above for details.
                                runtime·atomicstore(&m->waitsemalock, 0);
                                runtime·lwp_park(&ts, 0, &m->waitsemacount, nil);
                        }
                        // reacquire lock
                        while(runtime·xchg(&m->waitsemalock, 1))
                                runtime·osyield();
                }

                // lock held (again)
                if(m->waitsemacount != 0) {
                        // semaphore is available.
                        m->waitsemacount--;
                        // spin-mutex unlock
                        runtime·atomicstore(&m->waitsemalock, 0);
                        return 0;  // semaphore acquired
                }

                // semaphore not available.
                // if there is a timeout, stop now.
                // otherwise keep trying.
                if(ns >= 0)
                        break;
        }

        // lock held but giving up
        // spin-mutex unlock
        runtime·atomicstore(&m->waitsemalock, 0);
        return -1;
}

void
runtime·semawakeup(M *mp)
{
        uint32 ret;

        // spin-mutex lock
        while(runtime·xchg(&mp->waitsemalock, 1))
                runtime·osyield();
        mp->waitsemacount++;
        // TODO(jsing) - potential deadlock, see semasleep() for details.
        // Confirm that LWP is parked before unparking...
        ret = runtime·lwp_unpark(mp->procid, &mp->waitsemacount);
        if(ret != 0 && ret != ESRCH)
                runtime·printf("thrwakeup addr=%p sem=%d ret=%d\n", &mp->waitsemacount, mp->waitsemacount, ret);
        // spin-mutex unlock
        runtime·atomicstore(&mp->waitsemalock, 0);
}

void
runtime·newosproc(M *mp, void *stk)
{
        UcontextT uc;
        int32 ret;

        if(0) {
                runtime·printf(
                        "newosproc stk=%p m=%p g=%p id=%d/%d ostk=%p\n",
                        stk, mp, mp->g0, mp->id, (int32)mp->tls[0], &mp);
        }

        mp->tls[0] = mp->id;    // so 386 asm can find it

        runtime·getcontext(&uc);
        
        uc.uc_flags = _UC_SIGMASK | _UC_CPU;
        uc.uc_link = nil;
        uc.uc_sigmask = sigset_all;

        runtime·lwp_mcontext_init(&uc.uc_mcontext, stk, mp, mp->g0, runtime·mstart);

        ret = runtime·lwp_create(&uc, 0, &mp->procid);

        if(ret < 0) {
                runtime·printf("runtime: failed to create new OS thread (have %d already; errno=%d)\n", runtime·mcount() - 1, -ret);
                runtime·throw("runtime.newosproc");
        }
}

void
runtime·osinit(void)
{
        runtime·ncpu = getncpu();
}

void
runtime·get_random_data(byte **rnd, int32 *rnd_len)
{
        #pragma dataflag NOPTR
        static byte urandom_data[HashRandomBytes];
        int32 fd;
        fd = runtime·open("/dev/urandom", 0 /* O_RDONLY */, 0);
        if(runtime·read(fd, urandom_data, HashRandomBytes) == HashRandomBytes) {
                *rnd = urandom_data;
                *rnd_len = HashRandomBytes;
        } else {
                *rnd = nil;
                *rnd_len = 0;
        }
        runtime·close(fd);
}

void
runtime·goenvs(void)
{
        runtime·goenvs_unix();
}

// Called to initialize a new m (including the bootstrap m).
// Called on the parent thread (main thread in case of bootstrap), can allocate memory.
void
runtime·mpreinit(M *mp)
{
        mp->gsignal = runtime·malg(32*1024);
}

// Called to initialize a new m (including the bootstrap m).
// Called on the new thread, can not allocate memory.
void
runtime·minit(void)
{
        m->procid = runtime·lwp_self();

        // Initialize signal handling
        runtime·signalstack((byte*)m->gsignal->stackguard - StackGuard, 32*1024);
        runtime·sigprocmask(SIG_SETMASK, &sigset_none, nil);
}

// Called from dropm to undo the effect of an minit.
void
runtime·unminit(void)
{
        runtime·signalstack(nil, 0);
}

void
runtime·sigpanic(void)
{
        if(!runtime·canpanic(g))
                runtime·throw("unexpected signal during runtime execution");

        switch(g->sig) {
        case SIGBUS:
                if(g->sigcode0 == BUS_ADRERR && g->sigcode1 < 0x1000 || g->paniconfault) {
                        if(g->sigpc == 0)
                                runtime·panicstring("call of nil func value");
                        runtime·panicstring("invalid memory address or nil pointer dereference");
                }
                runtime·printf("unexpected fault address %p\n", g->sigcode1);
                runtime·throw("fault");
        case SIGSEGV:
                if((g->sigcode0 == 0 || g->sigcode0 == SEGV_MAPERR || g->sigcode0 == SEGV_ACCERR) && g->sigcode1 < 0x1000 || g->paniconfault) {
                        if(g->sigpc == 0)
                                runtime·panicstring("call of nil func value");
                        runtime·panicstring("invalid memory address or nil pointer dereference");
                }
                runtime·printf("unexpected fault address %p\n", g->sigcode1);
                runtime·throw("fault");
        case SIGFPE:
                switch(g->sigcode0) {
                case FPE_INTDIV:
                        runtime·panicstring("integer divide by zero");
                case FPE_INTOVF:
                        runtime·panicstring("integer overflow");
                }
                runtime·panicstring("floating point error");
        }
        runtime·panicstring(runtime·sigtab[g->sig].name);
}

uintptr
runtime·memlimit(void)
{
        return 0;
}

extern void runtime·sigtramp(void);

typedef struct sigaction {
        union {
                void    (*_sa_handler)(int32);
                void    (*_sa_sigaction)(int32, Siginfo*, void *);
        } _sa_u;                        /* signal handler */
        uint32  sa_mask[4];             /* signal mask to apply */
        int32   sa_flags;               /* see signal options below */
} Sigaction;

void
runtime·setsig(int32 i, GoSighandler *fn, bool restart)
{
        Sigaction sa;

        runtime·memclr((byte*)&sa, sizeof sa);
        sa.sa_flags = SA_SIGINFO|SA_ONSTACK;
        if(restart)
                sa.sa_flags |= SA_RESTART;
        sa.sa_mask[0] = ~0U;
        sa.sa_mask[1] = ~0U;
        sa.sa_mask[2] = ~0U;
        sa.sa_mask[3] = ~0U;
        if (fn == runtime·sighandler)
                fn = (void*)runtime·sigtramp;
        sa._sa_u._sa_sigaction = (void*)fn;
        runtime·sigaction(i, &sa, nil);
}

GoSighandler*
runtime·getsig(int32 i)
{
        Sigaction sa;

        runtime·memclr((byte*)&sa, sizeof sa);
        runtime·sigaction(i, nil, &sa);
        if((void*)sa._sa_u._sa_sigaction == runtime·sigtramp)
                return runtime·sighandler;
        return (void*)sa._sa_u._sa_sigaction;
}

void
runtime·signalstack(byte *p, int32 n)
{
        StackT st;

        st.ss_sp = (void*)p;
        st.ss_size = n;
        st.ss_flags = 0;
        if(p == nil)
                st.ss_flags = SS_DISABLE;
        runtime·sigaltstack(&st, nil);
}

void
runtime·unblocksignals(void)
{
        runtime·sigprocmask(SIG_SETMASK, &sigset_none, nil);
}
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root/src/pkg/runtime/os_netbsd.c

DEFINITIONS
