[apple/xnu.git] / bsd / dev / ppc / unix_signal.c

/*
 * Copyright (c) 2000 Apple Computer, Inc. All rights reserved.
 *
 * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
 * 
 * This file contains Original Code and/or Modifications of Original Code
 * as defined in and that are subject to the Apple Public Source License
 * Version 2.0 (the 'License'). You may not use this file except in
 * compliance with the License. The rights granted to you under the License
 * may not be used to create, or enable the creation or redistribution of,
 * unlawful or unlicensed copies of an Apple operating system, or to
 * circumvent, violate, or enable the circumvention or violation of, any
 * terms of an Apple operating system software license agreement.
 * 
 * Please obtain a copy of the License at
 * http://www.opensource.apple.com/apsl/ and read it before using this file.
 * 
 * The Original Code and all software distributed under the License are
 * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
 * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
 * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
 * Please see the License for the specific language governing rights and
 * limitations under the License.
 * 
 * @APPLE_OSREFERENCE_LICENSE_HEADER_END@
 */
/* 
 * Copyright (c) 1999 Apple Computer, Inc. All rights reserved.
 */

#include <mach/mach_types.h>
#include <mach/exception_types.h>

#include <sys/param.h>
#include <sys/proc_internal.h>
#include <sys/user.h>
#include <sys/ucontext.h>
#include <sys/sysproto.h>
#include <sys/systm.h>
#include <sys/ux_exception.h>

#include <ppc/signal.h>
#include <sys/signalvar.h>
#include <sys/kdebug.h>
#include <sys/wait.h>
#include <kern/thread.h>
#include <mach/ppc/thread_status.h>
#include <ppc/proc_reg.h>

// #include <machine/thread.h> XXX include path messed up for some reason...

/* XXX functions not in a Mach headers */
extern kern_return_t thread_getstatus(register thread_t act, int flavor,
                        thread_state_t tstate, mach_msg_type_number_t *count);
extern int is_64signalregset(void);
extern unsigned int get_msr_exportmask(void);
extern kern_return_t thread_setstatus(thread_t thread, int flavor,
                        thread_state_t tstate, mach_msg_type_number_t count);
extern void ppc_checkthreadstate(void *, int);
extern struct savearea_vec *find_user_vec_curr(void);
extern int thread_enable_fpe(thread_t act, int onoff);



#define C_32_REDZONE_LEN        224
#define C_32_STK_ALIGN          16
#define C_32_PARAMSAVE_LEN      64
#define C_32_LINKAGE_LEN        48

#define C_64_REDZONE_LEN        320
#define C_64_STK_ALIGN          32
#define C_64_PARAMSAVE_LEN      64
#define C_64_LINKAGE_LEN        48

#define TRUNC_DOWN32(a,b,c)     ((((uint32_t)a)-(b)) & ((uint32_t)(-(c))))
#define TRUNC_DOWN64(a,b,c)     ((((uint64_t)a)-(b)) & ((uint64_t)(-(c))))

/*
 * The stack layout possibilities (info style); This needs to mach with signal trampoline code
 *
 * Traditional:                 1
 * Traditional64:               20
 * Traditional64with vec:       25
 * 32bit context                30
 * 32bit context with vector    35
 * 64bit context                40
 * 64bit context with vector    45
 * Dual context                 50
 * Dual context with vector     55
 *
 */
 
#define UC_TRAD                 1
#define UC_TRAD_VEC             6
#define UC_TRAD64               20
#define UC_TRAD64_VEC           25
#define UC_FLAVOR               30
#define UC_FLAVOR_VEC           35
#define UC_FLAVOR64             40
#define UC_FLAVOR64_VEC         45
#define UC_DUAL                 50
#define UC_DUAL_VEC             55

 /* The following are valid mcontext sizes */
#define UC_FLAVOR_SIZE ((PPC_THREAD_STATE_COUNT + PPC_EXCEPTION_STATE_COUNT + PPC_FLOAT_STATE_COUNT) * sizeof(int))

#define UC_FLAVOR_VEC_SIZE ((PPC_THREAD_STATE_COUNT + PPC_EXCEPTION_STATE_COUNT + PPC_FLOAT_STATE_COUNT + PPC_VECTOR_STATE_COUNT) * sizeof(int))

#define UC_FLAVOR64_SIZE ((PPC_THREAD_STATE64_COUNT + PPC_EXCEPTION_STATE64_COUNT + PPC_FLOAT_STATE_COUNT) * sizeof(int))

#define UC_FLAVOR64_VEC_SIZE ((PPC_THREAD_STATE64_COUNT + PPC_EXCEPTION_STATE64_COUNT + PPC_FLOAT_STATE_COUNT + PPC_VECTOR_STATE_COUNT) * sizeof(int))


/*
 * NOTE: Source and target may *NOT* overlap!
 */
static void
ucontext_32to64(struct ucontext64 *in, struct user_ucontext64 *out)
{
        out->uc_onstack         = in->uc_onstack;
        out->uc_sigmask         = in->uc_sigmask;

        /* internal "structure assign" */
        out->uc_stack.ss_sp     = CAST_USER_ADDR_T(in->uc_stack.ss_sp);
        out->uc_stack.ss_size   = in->uc_stack.ss_size;
        out->uc_stack.ss_flags  = in->uc_stack.ss_flags;

        out->uc_link            = CAST_USER_ADDR_T(in->uc_link);
        out->uc_mcsize          = in->uc_mcsize;
        out->uc_mcontext64      = CAST_USER_ADDR_T(in->uc_mcontext64);
}

/*
 * This conversion is safe, since if we are converting for a 32 bit process,
 * then it's values of uc-stack.ss_size and uc_mcsize will never exceed 4G.
 *
 * NOTE: Source and target may *NOT* overlap!
 */
static void
ucontext_64to32(struct user_ucontext64 *in, struct ucontext64 *out)
{
        out->uc_onstack         = in->uc_onstack;
        out->uc_sigmask         = in->uc_sigmask;

        /* internal "structure assign" */
        out->uc_stack.ss_sp     = CAST_DOWN(void *,in->uc_stack.ss_sp);
        out->uc_stack.ss_size   = in->uc_stack.ss_size; /* range reduction */
        out->uc_stack.ss_flags  = in->uc_stack.ss_flags;

        out->uc_link            = CAST_DOWN(void *,in->uc_link);
        out->uc_mcsize          = in->uc_mcsize;        /* range reduction */
        out->uc_mcontext64      = CAST_DOWN(void *,in->uc_mcontext64);
}

/*
 * NOTE: Source and target may *NOT* overlap!
 */
static void
siginfo_64to32(user_siginfo_t *in, siginfo_t *out)
{
        out->si_signo   = in->si_signo;
        out->si_errno   = in->si_errno;
        out->si_code    = in->si_code;
        out->si_pid     = in->si_pid;
        out->si_uid     = in->si_uid;
        out->si_status  = in->si_status;
        out->si_addr    = CAST_DOWN(void *,in->si_addr);
        /* following cast works for sival_int because of padding */
        out->si_value.sival_ptr = CAST_DOWN(void *,in->si_value.sival_ptr);
        out->si_band    = in->si_band;                  /* range reduction */
        out->pad[0]     = in->pad[0];                   /* mcontext.ss.r1 */
}


/*
 * Arrange for this process to run a signal handler
 */

void
sendsig(struct proc *p, user_addr_t catcher, int sig, int mask, __unused u_long code)
{
        kern_return_t kretn;
        struct mcontext mctx;
        user_addr_t p_mctx = USER_ADDR_NULL;            /* mcontext dest. */
        struct mcontext64 mctx64;
        user_addr_t p_mctx64 = USER_ADDR_NULL;          /* mcontext dest. */
        struct user_ucontext64 uctx;
        user_addr_t p_uctx;             /* user stack addr top copy ucontext */
        user_siginfo_t sinfo;
        user_addr_t p_sinfo;            /* user stack addr top copy siginfo */
        struct sigacts *ps = p->p_sigacts;
        int oonstack;
        user_addr_t sp;
        mach_msg_type_number_t state_count;
        thread_t th_act;
        struct uthread *ut;
        int infostyle = UC_TRAD;
        int dualcontext =0;
        user_addr_t trampact;
        int vec_used = 0;
        int stack_size = 0;
        void * tstate;
        int flavor;
        int ctx32 = 1;

        th_act = current_thread();
        ut = get_bsdthread_info(th_act);

        
        if (p->p_sigacts->ps_siginfo & sigmask(sig)) {
                infostyle = UC_FLAVOR;
        }
        if(is_64signalregset() && (infostyle == UC_FLAVOR)) {
                dualcontext = 1;
                infostyle = UC_DUAL;    
        }
        if (p->p_sigacts->ps_64regset & sigmask(sig)) {
                dualcontext = 0;
                ctx32 = 0;
                infostyle = UC_FLAVOR64;
        }
        /* treat 64 bit processes as having used 64 bit registers */
        if ((IS_64BIT_PROCESS(p) || is_64signalregset()) &&
            (infostyle == UC_TRAD)) {
                ctx32=0;
                infostyle = UC_TRAD64;
        }
        if (IS_64BIT_PROCESS(p)) {
                ctx32=0;
                dualcontext = 0;
        }
        
        /* I need this for SIGINFO anyway */
        flavor = PPC_THREAD_STATE;
        tstate = (void *)&mctx.ss;
        state_count = PPC_THREAD_STATE_COUNT;
        if (thread_getstatus(th_act, flavor, (thread_state_t)tstate, &state_count)  != KERN_SUCCESS)
                goto bad;

        if ((ctx32 == 0) || dualcontext) {
                flavor = PPC_THREAD_STATE64;
                tstate = (void *)&mctx64.ss;
                state_count = PPC_THREAD_STATE64_COUNT;
                if (thread_getstatus(th_act, flavor, (thread_state_t)tstate, &state_count)  != KERN_SUCCESS)
                    goto bad;
        }

        if ((ctx32 == 1) || dualcontext) {
                flavor = PPC_EXCEPTION_STATE;
                tstate = (void *)&mctx.es;
                state_count = PPC_EXCEPTION_STATE_COUNT;
                if (thread_getstatus(th_act, flavor, (thread_state_t)tstate, &state_count)  != KERN_SUCCESS)
                    goto bad;
       } 
       
        if ((ctx32 == 0) || dualcontext) {
                flavor = PPC_EXCEPTION_STATE64;
                tstate = (void *)&mctx64.es;
                state_count = PPC_EXCEPTION_STATE64_COUNT;
       
                if (thread_getstatus(th_act, flavor, (thread_state_t)tstate, &state_count)  != KERN_SUCCESS)
                    goto bad;
                
        }
       

        if ((ctx32 == 1) || dualcontext) {
                flavor = PPC_FLOAT_STATE;
                tstate = (void *)&mctx.fs;
                state_count = PPC_FLOAT_STATE_COUNT;
                if (thread_getstatus(th_act, flavor, (thread_state_t)tstate, &state_count)  != KERN_SUCCESS)
                    goto bad;
       } 
       
        if ((ctx32 == 0) || dualcontext) {
                flavor = PPC_FLOAT_STATE;
                tstate = (void *)&mctx64.fs;
                state_count = PPC_FLOAT_STATE_COUNT;
                       if (thread_getstatus(th_act, flavor, (thread_state_t)tstate, &state_count)  != KERN_SUCCESS)
                    goto bad;
                
        }


        if (find_user_vec_curr()) {
                vec_used = 1;

                if ((ctx32 == 1) || dualcontext) {
                    flavor = PPC_VECTOR_STATE;
                    tstate = (void *)&mctx.vs;
                    state_count = PPC_VECTOR_STATE_COUNT;
                    if (thread_getstatus(th_act, flavor, (thread_state_t)tstate, &state_count)  != KERN_SUCCESS)
                    goto bad;
                    infostyle += 5;
            } 
       
            if ((ctx32 == 0) || dualcontext) {
                    flavor = PPC_VECTOR_STATE;
                    tstate = (void *)&mctx64.vs;
                    state_count = PPC_VECTOR_STATE_COUNT;
                    if (thread_getstatus(th_act, flavor, (thread_state_t)tstate, &state_count)  != KERN_SUCCESS)
                        goto bad;
                    infostyle += 5;
           }
        }  

        trampact = ps->ps_trampact[sig];
        oonstack = ps->ps_sigstk.ss_flags & SA_ONSTACK;

        /* figure out where our new stack lives */
        if ((ps->ps_flags & SAS_ALTSTACK) && !oonstack &&
                (ps->ps_sigonstack & sigmask(sig))) {
                sp = ps->ps_sigstk.ss_sp;
                sp += ps->ps_sigstk.ss_size;
                stack_size = ps->ps_sigstk.ss_size;
                ps->ps_sigstk.ss_flags |= SA_ONSTACK;
        }
        else {
                if (ctx32 == 0)
                        sp = mctx64.ss.r1;
                else
                        sp = CAST_USER_ADDR_T(mctx.ss.r1);
        }

        
        /* put siginfo on top */
        
        /* preserve RED ZONE area */
        if (IS_64BIT_PROCESS(p))
                sp = TRUNC_DOWN64(sp, C_64_REDZONE_LEN, C_64_STK_ALIGN);
        else
                sp = TRUNC_DOWN32(sp, C_32_REDZONE_LEN, C_32_STK_ALIGN);

        /* next are the saved registers */
        if ((ctx32 == 0) || dualcontext) {
            sp -= sizeof(struct mcontext64);
            p_mctx64 = sp;
        }
        if ((ctx32 == 1) || dualcontext) {
            sp -= sizeof(struct mcontext);
            p_mctx = sp;
        }    
        
        if (IS_64BIT_PROCESS(p)) {
                /* context goes first on stack */
                sp -= sizeof(struct user_ucontext64);
                p_uctx = sp;

                /* this is where siginfo goes on stack */
                sp -= sizeof(user_siginfo_t);
                p_sinfo = sp;
                
                sp = TRUNC_DOWN64(sp, C_64_PARAMSAVE_LEN+C_64_LINKAGE_LEN, C_64_STK_ALIGN);
        } else {
                /*
                 * struct ucontext and struct ucontext64 are identical in
                 * size and content; the only difference is the internal
                 * pointer type for the last element, which makes no
                 * difference for the copyout().
                 */

                /* context goes first on stack */
                sp -= sizeof(struct ucontext64);
                p_uctx = sp;

                /* this is where siginfo goes on stack */
                sp -= sizeof(siginfo_t);
                p_sinfo = sp;

                sp = TRUNC_DOWN32(sp, C_32_PARAMSAVE_LEN+C_32_LINKAGE_LEN, C_32_STK_ALIGN);
        }

        uctx.uc_onstack = oonstack;
        uctx.uc_sigmask = mask;
        uctx.uc_stack.ss_sp = sp;
        uctx.uc_stack.ss_size = stack_size;
        if (oonstack)
                uctx.uc_stack.ss_flags |= SS_ONSTACK;
                
        uctx.uc_link = 0;
        if (ctx32 == 0)
                uctx.uc_mcsize = (size_t)((PPC_EXCEPTION_STATE64_COUNT + PPC_THREAD_STATE64_COUNT + PPC_FLOAT_STATE_COUNT) * sizeof(int));
        else
                uctx.uc_mcsize = (size_t)((PPC_EXCEPTION_STATE_COUNT + PPC_THREAD_STATE_COUNT + PPC_FLOAT_STATE_COUNT) * sizeof(int));
        
        if (vec_used) 
                uctx.uc_mcsize += (size_t)(PPC_VECTOR_STATE_COUNT * sizeof(int));
        
        if (ctx32 == 0)
             uctx.uc_mcontext64 = p_mctx64;
       else
            uctx.uc_mcontext64 = p_mctx;

        /* setup siginfo */
        bzero((caddr_t)&sinfo, sizeof(user_siginfo_t));
        sinfo.si_signo = sig;
        if (ctx32 == 0) {
                sinfo.si_addr = mctx64.ss.srr0;
                sinfo.pad[0] = mctx64.ss.r1;
        } else {
                sinfo.si_addr = CAST_USER_ADDR_T(mctx.ss.srr0);
                sinfo.pad[0] = CAST_USER_ADDR_T(mctx.ss.r1);
        }

        switch (sig) {
                case SIGCHLD:
                        sinfo.si_pid = p->si_pid;
                        p->si_pid =0;
                        sinfo.si_status = p->si_status;
                        p->si_status = 0;
                        sinfo.si_uid = p->si_uid;
                        p->si_uid =0;
                        sinfo.si_code = p->si_code;
                        p->si_code = 0;
                        if (sinfo.si_code == CLD_EXITED) {
                                if (WIFEXITED(sinfo.si_status)) 
                                        sinfo.si_code = CLD_EXITED;
                                else if (WIFSIGNALED(sinfo.si_status)) {
                                        if (WCOREDUMP(sinfo.si_status))
                                                sinfo.si_code = CLD_DUMPED;
                                        else    
                                                sinfo.si_code = CLD_KILLED;
                                }
                        }
                        break;
                case SIGILL:
                        /*
                         * If it's 64 bit and not a dual context, mctx will
                         * contain uninitialized data, so we have to use
                         * mctx64 here.
                         */
                        if(ctx32 == 0) {
                                if (mctx64.ss.srr1 & (1 << (31 - SRR1_PRG_ILL_INS_BIT)))
                                        sinfo.si_code = ILL_ILLOPC;
                                else if (mctx64.ss.srr1 & (1 << (31 - SRR1_PRG_PRV_INS_BIT)))
                                        sinfo.si_code = ILL_PRVOPC;
                                else if (mctx64.ss.srr1 & (1 << (31 - SRR1_PRG_TRAP_BIT)))
                                        sinfo.si_code = ILL_ILLTRP;
                                else
                                        sinfo.si_code = ILL_NOOP;
                        } else {
                                if (mctx.ss.srr1 & (1 << (31 - SRR1_PRG_ILL_INS_BIT)))
                                        sinfo.si_code = ILL_ILLOPC;
                                else if (mctx.ss.srr1 & (1 << (31 - SRR1_PRG_PRV_INS_BIT)))
                                        sinfo.si_code = ILL_PRVOPC;
                                else if (mctx.ss.srr1 & (1 << (31 - SRR1_PRG_TRAP_BIT)))
                                        sinfo.si_code = ILL_ILLTRP;
                                else
                                        sinfo.si_code = ILL_NOOP;
                        }
                        break;
                case SIGFPE:
#define FPSCR_VX        2
#define FPSCR_OX        3
#define FPSCR_UX        4
#define FPSCR_ZX        5
#define FPSCR_XX        6
                        /*
                         * If it's 64 bit and not a dual context, mctx will
                         * contain uninitialized data, so we have to use
                         * mctx64 here.
                         */
                        if(ctx32 == 0) {
                                if (mctx64.fs.fpscr & (1 << (31 - FPSCR_VX)))
                                        sinfo.si_code = FPE_FLTINV;
                                else if (mctx64.fs.fpscr & (1 << (31 - FPSCR_OX)))
                                        sinfo.si_code = FPE_FLTOVF;
                                else if (mctx64.fs.fpscr & (1 << (31 - FPSCR_UX)))
                                        sinfo.si_code = FPE_FLTUND;
                                else if (mctx64.fs.fpscr & (1 << (31 - FPSCR_ZX)))
                                        sinfo.si_code = FPE_FLTDIV;
                                else if (mctx64.fs.fpscr & (1 << (31 - FPSCR_XX)))
                                        sinfo.si_code = FPE_FLTRES;
                                else
                                        sinfo.si_code = FPE_NOOP;
                        } else {
                                if (mctx.fs.fpscr & (1 << (31 - FPSCR_VX)))
                                        sinfo.si_code = FPE_FLTINV;
                                else if (mctx.fs.fpscr & (1 << (31 - FPSCR_OX)))
                                        sinfo.si_code = FPE_FLTOVF;
                                else if (mctx.fs.fpscr & (1 << (31 - FPSCR_UX)))
                                        sinfo.si_code = FPE_FLTUND;
                                else if (mctx.fs.fpscr & (1 << (31 - FPSCR_ZX)))
                                        sinfo.si_code = FPE_FLTDIV;
                                else if (mctx.fs.fpscr & (1 << (31 - FPSCR_XX)))
                                        sinfo.si_code = FPE_FLTRES;
                                else
                                        sinfo.si_code = FPE_NOOP;
                        }
                        break;

                case SIGBUS:
                        if (ctx32 == 0) {
                                sinfo.si_addr = mctx64.es.dar;
                        } else {
                                sinfo.si_addr = CAST_USER_ADDR_T(mctx.es.dar);
                        }
                        /* on ppc we generate only if EXC_PPC_UNALIGNED */
                        sinfo.si_code = BUS_ADRALN;
                        break;

                case SIGSEGV:
                        /*
                         * If it's 64 bit and not a dual context, mctx will
                         * contain uninitialized data, so we have to use
                         * mctx64 here.
                         */
                        if (ctx32 == 0) {
                                sinfo.si_addr = mctx64.es.dar;
                                /* First check in srr1 and then in dsisr */
                                if (mctx64.ss.srr1 & (1 << (31 - DSISR_PROT_BIT)))
                                        sinfo.si_code = SEGV_ACCERR;
                                else if (mctx64.es.dsisr & (1 << (31 - DSISR_PROT_BIT)))
                                        sinfo.si_code = SEGV_ACCERR;
                                else
                                        sinfo.si_code = SEGV_MAPERR;
                        } else {
                                sinfo.si_addr = CAST_USER_ADDR_T(mctx.es.dar);
                                /* First check in srr1 and then in dsisr */
                                if (mctx.ss.srr1 & (1 << (31 - DSISR_PROT_BIT)))
                                        sinfo.si_code = SEGV_ACCERR;
                                else if (mctx.es.dsisr & (1 << (31 - DSISR_PROT_BIT)))
                                        sinfo.si_code = SEGV_ACCERR;
                                else
                                        sinfo.si_code = SEGV_MAPERR;
                        }
                        break;
                default:
                        break;
        }


        /* copy info out to user space */
        if (IS_64BIT_PROCESS(p)) {
                if (copyout(&uctx, p_uctx, sizeof(struct user_ucontext64)))
                        goto bad;
                if (copyout(&sinfo, p_sinfo, sizeof(user_siginfo_t)))
                        goto bad;
        } else {
                struct ucontext64 uctx32;
                siginfo_t sinfo32;

                ucontext_64to32(&uctx, &uctx32);
                if (copyout(&uctx32, p_uctx, sizeof(struct ucontext64)))
                        goto bad;

                siginfo_64to32(&sinfo,&sinfo32);
                if (copyout(&sinfo32, p_sinfo, sizeof(siginfo_t)))
                        goto bad;
        }
        if ((ctx32 == 0) || dualcontext) {
            /*
             * NOTE: Size of mcontext is not variant between 64bit and
             * 32bit programs usng 64bit registers.
             */
            if (copyout(&mctx64, p_mctx64, (vec_used? UC_FLAVOR64_VEC_SIZE: UC_FLAVOR64_SIZE)))
                goto bad;
        }
        if ((ctx32 == 1) || dualcontext) {
            if (copyout(&mctx, p_mctx, uctx.uc_mcsize))
                goto bad;
        }    


        /* Place our arguments in arg registers: rtm dependent */
        if(IS_64BIT_PROCESS(p)) {
                mctx64.ss.r3 = catcher;
                mctx64.ss.r4 = CAST_USER_ADDR_T(infostyle);
                mctx64.ss.r5 = CAST_USER_ADDR_T(sig);
                mctx64.ss.r6 = p_sinfo;
                mctx64.ss.r7 = p_uctx;

                mctx64.ss.srr0 = trampact;
                /* MSR_EXPORT_MASK_SET */
                mctx64.ss.srr1 = CAST_USER_ADDR_T(get_msr_exportmask());
                mctx64.ss.r1 = sp;
                state_count = PPC_THREAD_STATE64_COUNT;
                if ((kretn = thread_setstatus(th_act, PPC_THREAD_STATE64, (void *)&mctx64.ss, state_count))  != KERN_SUCCESS) {
                        panic("sendsig: thread_setstatus failed, ret = %08X\n", kretn);
                }       
        } else {
                mctx.ss.r3 = CAST_DOWN(unsigned long,catcher);
                mctx.ss.r4 = (unsigned long)infostyle;
                mctx.ss.r5 = (unsigned long)sig;
                mctx.ss.r6 = CAST_DOWN(unsigned long,p_sinfo);
                mctx.ss.r7 = CAST_DOWN(unsigned long,p_uctx);

                mctx.ss.srr0 = CAST_DOWN(unsigned long,trampact);
                /* MSR_EXPORT_MASK_SET */
                mctx.ss.srr1 = get_msr_exportmask();
                mctx.ss.r1 = CAST_DOWN(unsigned long,sp);
                state_count = PPC_THREAD_STATE_COUNT;
                if ((kretn = thread_setstatus(th_act, PPC_THREAD_STATE, (void *)&mctx.ss, state_count))  != KERN_SUCCESS) {
                        panic("sendsig: thread_setstatus failed, ret = %08X\n", kretn);
                }       
        }
        return;

bad:
        SIGACTION(p, SIGILL) = SIG_DFL;
        sig = sigmask(SIGILL);
        p->p_sigignore &= ~sig;
        p->p_sigcatch &= ~sig;
        ut->uu_sigmask &= ~sig;
        /* sendsig is called with signal lock held */
        psignal_lock(p, SIGILL, 0);
        return;
}

/*
 * System call to cleanup state after a signal
 * has been taken.  Reset signal mask and
 * stack state from context left by sendsig (above).
 * Return to previous pc and psl as specified by
 * context left by sendsig. Check carefully to
 * make sure that the user has not modified the
 * psl to gain improper priviledges or to cause
 * a machine fault.
 */

/* ARGSUSED */
int
sigreturn(struct proc *p, struct sigreturn_args *uap, __unused int *retval)
{
        struct user_ucontext64 uctx;

        char mactx[sizeof(struct mcontext64)];
        struct mcontext *p_mctx;
        struct mcontext64 *p_64mctx;
        int error;
        thread_t th_act;
        struct sigacts *ps = p->p_sigacts;
        sigset_t mask;  
        user_addr_t action;
        unsigned long state_count;
        unsigned int state_flavor;
        struct uthread * ut;
        int vec_used = 0;
        void *tsptr, *fptr, *vptr;
        int infostyle = uap->infostyle;

        th_act = current_thread();

        ut = (struct uthread *)get_bsdthread_info(th_act);
        if (IS_64BIT_PROCESS(p)) {
                error = copyin(uap->uctx, &uctx, sizeof(struct user_ucontext64));
                if (error)
                        return(error);
        } else {
                struct ucontext64 uctx32;

                /*
                 * struct ucontext and struct ucontext64 are identical in
                 * size and content; the only difference is the internal
                 * pointer type for the last element, which makes no
                 * difference for the copyin().
                 */
                error = copyin(uap->uctx, &uctx32, sizeof(struct ucontext));
                if (error)
                        return(error);
                ucontext_32to64(&uctx32, &uctx);
        }
        

        /* validate the machine context size */
        switch (uctx.uc_mcsize) {
                case UC_FLAVOR64_VEC_SIZE:
                case UC_FLAVOR64_SIZE:
                case UC_FLAVOR_VEC_SIZE:
                case UC_FLAVOR_SIZE:
                        break;
                default:
                        return(EINVAL);
        }

        /*
         * The 64 bit process mcontext is identical to the mcontext64, so
         * there is no conversion necessary.
         */
        error = copyin(uctx.uc_mcontext64, mactx, uctx.uc_mcsize);
        if (error)
                return(error);
        
        if ((uctx.uc_onstack & 01))
                        p->p_sigacts->ps_sigstk.ss_flags |= SA_ONSTACK;
        else
                p->p_sigacts->ps_sigstk.ss_flags &= ~SA_ONSTACK;

        ut->uu_sigmask = uctx.uc_sigmask & ~sigcantmask;
        if (ut->uu_siglist & ~ut->uu_sigmask)
                signal_setast(current_thread());        

        vec_used = 0;
        switch (infostyle)  {
                case UC_FLAVOR64_VEC:
                case UC_TRAD64_VEC:
                                vec_used = 1;
                case UC_TRAD64:
                case UC_FLAVOR64:  {
                            p_64mctx = (struct mcontext64 *)mactx;      
                            tsptr = (void *)&p_64mctx->ss;
                            fptr = (void *)&p_64mctx->fs;
                            vptr = (void *)&p_64mctx->vs;
                            state_flavor = PPC_THREAD_STATE64;
                            state_count = PPC_THREAD_STATE64_COUNT;
                    } 
                    break;
                case UC_FLAVOR_VEC :
                case UC_TRAD_VEC :
                                vec_used = 1;
                case UC_FLAVOR :
                case UC_TRAD :
                default: {
                        p_mctx = (struct mcontext *)mactx;      
                        tsptr = (void *)&p_mctx->ss;
                        fptr = (void *)&p_mctx->fs;
                        vptr = (void *)&p_mctx->vs;
                        state_flavor = PPC_THREAD_STATE;
                        state_count = PPC_THREAD_STATE_COUNT;
                }
                break;
        } /* switch () */

        /* validate the thread state, set/reset appropriate mode bits in srr1 */
        (void)ppc_checkthreadstate(tsptr, state_flavor);

        if (thread_setstatus(th_act, state_flavor, tsptr, state_count)  != KERN_SUCCESS) {
                return(EINVAL);
        }       

        state_count = PPC_FLOAT_STATE_COUNT;
        if (thread_setstatus(th_act, PPC_FLOAT_STATE, fptr, state_count)  != KERN_SUCCESS) {
                return(EINVAL);
        }       

        mask = sigmask(SIGFPE);
        if (((ut->uu_sigmask & mask) == 0) && (p->p_sigcatch & mask) && ((p->p_sigignore & mask) == 0)) {
                action = ps->ps_sigact[SIGFPE];
                if((action != SIG_DFL) && (action != SIG_IGN)) {
                        thread_enable_fpe(th_act, 1);
                }
        }

        if (vec_used) {
                state_count = PPC_VECTOR_STATE_COUNT;
                if (thread_setstatus(th_act, PPC_VECTOR_STATE, vptr, state_count)  != KERN_SUCCESS) {
                        return(EINVAL);
                }       
        }
        return (EJUSTRETURN);
}

/*
 * machine_exception() performs MD translation
 * of a mach exception to a unix signal and code.
 */

boolean_t
machine_exception(
    int         exception,
    int         code,
    __unused int subcode,
    int         *unix_signal,
    int         *unix_code
)
{
    switch(exception) {

    case EXC_BAD_INSTRUCTION:
        *unix_signal = SIGILL;
        *unix_code = code;
        break;

    case EXC_ARITHMETIC:
        *unix_signal = SIGFPE;
        *unix_code = code;
        break;

    case EXC_SOFTWARE:
        if (code == EXC_PPC_TRAP) {
                *unix_signal = SIGTRAP;
                *unix_code = code;
                break;
        } else
                return(FALSE);

    default:
        return(FALSE);
    }
   
    return(TRUE);
}