[apple/xnu.git] / bsd / dev / i386 / unix_signal.c

/*
 * Copyright (c) 2000-2006 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) 1992 NeXT, Inc.
 *
 * HISTORY
 * 13 May 1992 ? at NeXT
 *      Created.
 */

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

#include <kern/thread.h>

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

#include <sys/ux_exception.h>

#include <mach/thread_act.h>    /* for thread_abort_safely */
#include <mach/thread_status.h>

#include <i386/eflags.h>
#include <i386/psl.h>
#include <i386/machine_routines.h>
#include <i386/seg.h>
#include <i386/fpu.h>

#include <machine/pal_routines.h>

#include <sys/kdebug.h>
#include <sys/sdt.h>


/* Forward: */
extern kern_return_t thread_getstatus(thread_t act, int flavor,
    thread_state_t tstate, mach_msg_type_number_t *count);
extern kern_return_t thread_setstatus(thread_t thread, int flavor,
    thread_state_t tstate, mach_msg_type_number_t count);

/* Signal handler flavors supported */
/* These defns should match the Libc implmn */
#define UC_TRAD                 1
#define UC_FLAVOR               30
#define UC_SET_ALT_STACK        0x40000000
#define UC_RESET_ALT_STACK      0x80000000

#define C_32_STK_ALIGN          16
#define C_64_STK_ALIGN          16
#define C_64_REDZONE_LEN        128
#define TRUNC_DOWN32(a, c)       ((((uint32_t)a)-(c)) & ((uint32_t)(-(c))))
#define TRUNC_DOWN64(a, c)       ((((uint64_t)a)-(c)) & ((uint64_t)(-(c))))

/*
 * Send an interrupt to process.
 *
 * Stack is set up to allow sigcode stored
 * in u. to call routine, followed by chmk
 * to sigreturn routine below.  After sigreturn
 * resets the signal mask, the stack, the frame
 * pointer, and the argument pointer, it returns
 * to the user specified pc, psl.
 */
struct sigframe32 {
        int             retaddr;
        user32_addr_t   catcher; /* sig_t */
        int             sigstyle;
        int             sig;
        user32_addr_t   sinfo;  /* siginfo32_t* */
        user32_addr_t   uctx;   /* struct ucontext32 */
        user32_addr_t   token;
};

/*
 * Declare table of structure flavors and sizes for 64-bit and 32-bit processes
 * for the cases of extended states (plain FP, or AVX):
 */
typedef struct {
        int flavor; natural_t state_count; size_t  mcontext_size;
} xstate_info_t;
static const xstate_info_t thread_state64[] = {
        [FP]          = { x86_FLOAT_STATE64, x86_FLOAT_STATE64_COUNT, sizeof(struct mcontext64) },
        [FP_FULL]     = { x86_FLOAT_STATE64, x86_FLOAT_STATE64_COUNT, sizeof(struct mcontext64_full) },
        [AVX]         = { x86_AVX_STATE64, x86_AVX_STATE64_COUNT, sizeof(struct mcontext_avx64) },
        [AVX_FULL]    = { x86_AVX_STATE64, x86_AVX_STATE64_COUNT, sizeof(struct mcontext_avx64_full) },
        [AVX512]      = { x86_AVX512_STATE64, x86_AVX512_STATE64_COUNT, sizeof(struct mcontext_avx512_64) },
        [AVX512_FULL] = { x86_AVX512_STATE64, x86_AVX512_STATE64_COUNT, sizeof(struct mcontext_avx512_64_full) }
};
static const xstate_info_t thread_state32[] = {
        [FP]     = { x86_FLOAT_STATE32, x86_FLOAT_STATE32_COUNT, sizeof(struct mcontext32) },
        [AVX]    = { x86_AVX_STATE32, x86_AVX_STATE32_COUNT, sizeof(struct mcontext_avx32) },
        [AVX512] = { x86_AVX512_STATE32, x86_AVX512_STATE32_COUNT, sizeof(struct mcontext_avx512_32) }
};

/*
 * NOTE: Source and target may *NOT* overlap!
 * XXX: Unify with bsd/kern/kern_exit.c
 */
static void
siginfo_user_to_user32_x86(user_siginfo_t *in, user32_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_EXPLICIT(user32_addr_t, in->si_addr);
        /* following cast works for sival_int because of padding */
        out->si_value.sival_ptr = CAST_DOWN_EXPLICIT(user32_addr_t, in->si_value.sival_ptr);
        out->si_band    = in->si_band;                  /* range reduction */
        out->__pad[0]   = in->pad[0];                   /* mcontext.ss.r1 */
}

static void
siginfo_user_to_user64_x86(user_siginfo_t *in, user64_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    = in->si_addr;
        out->si_value.sival_ptr = in->si_value.sival_ptr;
        out->si_band    = in->si_band;                  /* range reduction */
        out->__pad[0]   = in->pad[0];                   /* mcontext.ss.r1 */
}

void
sendsig(struct proc *p, user_addr_t ua_catcher, int sig, int mask, __unused uint32_t code)
{
        union {
                struct mcontext_avx32           mctx_avx32;
                struct mcontext_avx64           mctx_avx64;
                struct mcontext_avx64_full      mctx_avx64_full;
                struct mcontext_avx512_32       mctx_avx512_32;
                struct mcontext_avx512_64       mctx_avx512_64;
                struct mcontext_avx512_64_full  mctx_avx512_64_full;
        } mctx_store, *mctxp = &mctx_store;

        user_addr_t     ua_sp;
        user_addr_t     ua_fp;
        user_addr_t     ua_cr2;
        user_addr_t     ua_sip;
        user_addr_t     ua_uctxp;
        user_addr_t     ua_mctxp;
        user_siginfo_t  sinfo64;

        struct sigacts *ps = p->p_sigacts;
        int oonstack, flavor;
        user_addr_t trampact;
        int sigonstack;
        void * state, *fpstate;
        mach_msg_type_number_t state_count;

        thread_t thread;
        struct uthread * ut;
        int stack_size = 0;
        int infostyle = UC_TRAD;
        xstate_t        sig_xstate;
        user_addr_t     token_uctx;
        kern_return_t   kr;
        boolean_t       reset_ss = TRUE;

        thread = current_thread();
        ut = get_bsdthread_info(thread);

        if (p->p_sigacts->ps_siginfo & sigmask(sig)) {
                infostyle = UC_FLAVOR;
        }

        oonstack = ut->uu_sigstk.ss_flags & SA_ONSTACK;
        trampact = ps->ps_trampact[sig];
        sigonstack = (ps->ps_sigonstack & sigmask(sig));

        /*
         * init siginfo
         */
        proc_unlock(p);

        bzero((caddr_t)&sinfo64, sizeof(sinfo64));
        sinfo64.si_signo = sig;

        bzero(mctxp, sizeof(*mctxp));

        sig_xstate = current_xstate();

        if (proc_is64bit(p)) {
                x86_thread_state64_t    *tstate64;
                struct user_ucontext64  uctx64;
                user64_addr_t token;
                int task_has_ldt = thread_task_has_ldt(thread);

                if (task_has_ldt) {
                        flavor = x86_THREAD_FULL_STATE64;
                        state_count = x86_THREAD_FULL_STATE64_COUNT;
                        fpstate = (void *)&mctxp->mctx_avx64_full.fs;
                        sig_xstate |= STATE64_FULL;
                } else {
                        flavor = x86_THREAD_STATE64;
                        state_count = x86_THREAD_STATE64_COUNT;
                        fpstate = (void *)&mctxp->mctx_avx64.fs;
                }
                state = (void *)&mctxp->mctx_avx64.ss;

                /*
                 * The state copying is performed with pointers to fields in the state
                 * struct.  This works specifically because the mcontext is layed-out with the
                 * variable-sized FP-state as the last member.  However, with the requirement
                 * to support passing "full" 64-bit state to the signal handler, that layout has now
                 * changed (since the "full" state has a larger "ss" member than the non-"full"
                 * structure.  Because of this, and to retain the array-lookup method of determining
                 * structure sizes, we OR-in STATE64_FULL to sig_xstate to ensure the proper mcontext
                 * size is passed.
                 */

                if (thread_getstatus(thread, flavor, (thread_state_t)state, &state_count) != KERN_SUCCESS) {
                        goto bad;
                }

                if ((sig_xstate & STATE64_FULL) && mctxp->mctx_avx64.ss.cs != USER64_CS) {
                        if ((ut->uu_flag & UT_ALTSTACK) && !oonstack &&
                            (sigonstack)) {
                                reset_ss = TRUE;
                        } else {
                                reset_ss = FALSE;
                        }
                } else {
                        reset_ss = FALSE;
                }

                flavor      = thread_state64[sig_xstate].flavor;
                state_count = thread_state64[sig_xstate].state_count;
                if (thread_getstatus(thread, flavor, (thread_state_t)fpstate, &state_count) != KERN_SUCCESS) {
                        goto bad;
                }

                flavor = x86_EXCEPTION_STATE64;
                state_count = x86_EXCEPTION_STATE64_COUNT;
                state = (void *)&mctxp->mctx_avx64.es;
                if (thread_getstatus(thread, flavor, (thread_state_t)state, &state_count) != KERN_SUCCESS) {
                        goto bad;
                }

                tstate64 = &mctxp->mctx_avx64.ss;

                /* figure out where our new stack lives */
                if ((ut->uu_flag & UT_ALTSTACK) && !oonstack &&
                    (sigonstack)) {
                        ua_sp = ut->uu_sigstk.ss_sp;
                        stack_size = ut->uu_sigstk.ss_size;
                        ua_sp += stack_size;
                        ut->uu_sigstk.ss_flags |= SA_ONSTACK;
                } else {
                        if ((sig_xstate & STATE64_FULL) && tstate64->cs != USER64_CS) {
                                reset_ss = FALSE;
                        }
                        ua_sp = tstate64->rsp;
                }
                ua_cr2 = mctxp->mctx_avx64.es.faultvaddr;

                /* The x86_64 ABI defines a 128-byte red zone. */
                ua_sp -= C_64_REDZONE_LEN;

                ua_sp -= sizeof(struct user_ucontext64);
                ua_uctxp = ua_sp;                        // someone tramples the first word!

                ua_sp -= sizeof(user64_siginfo_t);
                ua_sip = ua_sp;

                ua_sp -= thread_state64[sig_xstate].mcontext_size;
                ua_mctxp = ua_sp;

                /*
                 * Align the frame and stack pointers to 16 bytes for SSE.
                 * (Note that we use 'ua_fp' as the base of the stack going forward)
                 */
                ua_fp = TRUNC_DOWN64(ua_sp, C_64_STK_ALIGN);

                /*
                 * But we need to account for the return address so the alignment is
                 * truly "correct" at _sigtramp
                 */
                ua_fp -= sizeof(user_addr_t);

                /*
                 * Generate the validation token for sigreturn
                 */
                token_uctx = ua_uctxp;
                kr = machine_thread_siguctx_pointer_convert_to_user(thread, &token_uctx);
                assert(kr == KERN_SUCCESS);
                token = (user64_addr_t)token_uctx ^ (user64_addr_t)ps->ps_sigreturn_token;

                /*
                 * Build the signal context to be used by sigreturn.
                 */
                bzero(&uctx64, sizeof(uctx64));

                uctx64.uc_onstack = oonstack;
                uctx64.uc_sigmask = mask;
                uctx64.uc_stack.ss_sp = ua_fp;
                uctx64.uc_stack.ss_size = stack_size;

                if (oonstack) {
                        uctx64.uc_stack.ss_flags |= SS_ONSTACK;
                }
                uctx64.uc_link = 0;

                uctx64.uc_mcsize = thread_state64[sig_xstate].mcontext_size;
                uctx64.uc_mcontext64 = ua_mctxp;

                if (copyout((caddr_t)&uctx64, ua_uctxp, sizeof(uctx64))) {
                        goto bad;
                }

                if (copyout((caddr_t)&mctx_store, ua_mctxp, thread_state64[sig_xstate].mcontext_size)) {
                        goto bad;
                }

                sinfo64.pad[0]  = tstate64->rsp;
                sinfo64.si_addr = tstate64->rip;

                tstate64->rip = trampact;
                tstate64->rsp = ua_fp;
                tstate64->rflags = get_eflags_exportmask();

                /*
                 * SETH - need to set these for processes with LDTs
                 */
                tstate64->cs = USER64_CS;
                tstate64->fs = NULL_SEG;
                /*
                 * Set gs to 0 here to prevent restoration of %gs on return-to-user.  If we
                 * did NOT do that here and %gs was non-zero, we'd blow away gsbase when
                 * we restore %gs in the kernel exit trampoline.
                 */
                tstate64->gs = 0;

                if (sig_xstate & STATE64_FULL) {
                        /* Reset DS, ES, and possibly SS */
                        if (reset_ss) {
                                /*
                                 * Restore %ss if (a) an altstack was used for signal delivery
                                 * or (b) %cs at the time of the signal was the default
                                 * (USER64_CS)
                                 */
                                mctxp->mctx_avx64_full.ss.ss = USER64_DS;
                        }
                        mctxp->mctx_avx64_full.ss.ds = USER64_DS;
                        mctxp->mctx_avx64_full.ss.es = 0;
                }

                /*
                 * Build the argument list for the signal handler.
                 * Handler should call sigreturn to get out of it
                 */
                tstate64->rdi = ua_catcher;
                tstate64->rsi = infostyle;
                tstate64->rdx = sig;
                tstate64->rcx = ua_sip;
                tstate64->r8  = ua_uctxp;
                tstate64->r9  = token;
        } else {
                x86_thread_state32_t    *tstate32;
                struct user_ucontext32  uctx32;
                struct sigframe32       frame32;
                user32_addr_t token;

                flavor = x86_THREAD_STATE32;
                state_count = x86_THREAD_STATE32_COUNT;
                state = (void *)&mctxp->mctx_avx32.ss;
                if (thread_getstatus(thread, flavor, (thread_state_t)state, &state_count) != KERN_SUCCESS) {
                        goto bad;
                }

                flavor = thread_state32[sig_xstate].flavor;
                state_count = thread_state32[sig_xstate].state_count;
                state = (void *)&mctxp->mctx_avx32.fs;
                if (thread_getstatus(thread, flavor, (thread_state_t)state, &state_count) != KERN_SUCCESS) {
                        goto bad;
                }

                flavor = x86_EXCEPTION_STATE32;
                state_count = x86_EXCEPTION_STATE32_COUNT;
                state = (void *)&mctxp->mctx_avx32.es;
                if (thread_getstatus(thread, flavor, (thread_state_t)state, &state_count) != KERN_SUCCESS) {
                        goto bad;
                }

                tstate32 = &mctxp->mctx_avx32.ss;

                /* figure out where our new stack lives */
                if ((ut->uu_flag & UT_ALTSTACK) && !oonstack &&
                    (sigonstack)) {
                        ua_sp = ut->uu_sigstk.ss_sp;
                        stack_size = ut->uu_sigstk.ss_size;
                        ua_sp += stack_size;
                        ut->uu_sigstk.ss_flags |= SA_ONSTACK;
                } else {
                        ua_sp = tstate32->esp;
                }
                ua_cr2 = mctxp->mctx_avx32.es.faultvaddr;

                ua_sp -= sizeof(struct user_ucontext32);
                ua_uctxp = ua_sp;                        // someone tramples the first word!

                ua_sp -= sizeof(user32_siginfo_t);
                ua_sip = ua_sp;

                ua_sp -= thread_state32[sig_xstate].mcontext_size;
                ua_mctxp = ua_sp;

                ua_sp -= sizeof(struct sigframe32);
                ua_fp = ua_sp;

                /*
                 * Align the frame and stack pointers to 16 bytes for SSE.
                 * (Note that we use 'fp' as the base of the stack going forward)
                 */
                ua_fp = TRUNC_DOWN32(ua_fp, C_32_STK_ALIGN);

                /*
                 * But we need to account for the return address so the alignment is
                 * truly "correct" at _sigtramp
                 */
                ua_fp -= sizeof(frame32.retaddr);

                /*
                 * Generate the validation token for sigreturn
                 */
                token_uctx = ua_uctxp;
                kr = machine_thread_siguctx_pointer_convert_to_user(thread, &token_uctx);
                assert(kr == KERN_SUCCESS);
                token = CAST_DOWN_EXPLICIT(user32_addr_t, token_uctx) ^
                    CAST_DOWN_EXPLICIT(user32_addr_t, ps->ps_sigreturn_token);

                /*
                 * Build the argument list for the signal handler.
                 * Handler should call sigreturn to get out of it
                 */
                frame32.retaddr = -1;
                frame32.sigstyle = infostyle;
                frame32.sig = sig;
                frame32.catcher = CAST_DOWN_EXPLICIT(user32_addr_t, ua_catcher);
                frame32.sinfo = CAST_DOWN_EXPLICIT(user32_addr_t, ua_sip);
                frame32.uctx = CAST_DOWN_EXPLICIT(user32_addr_t, ua_uctxp);
                frame32.token = token;

                if (copyout((caddr_t)&frame32, ua_fp, sizeof(frame32))) {
                        goto bad;
                }

                /*
                 * Build the signal context to be used by sigreturn.
                 */
                bzero(&uctx32, sizeof(uctx32));

                uctx32.uc_onstack = oonstack;
                uctx32.uc_sigmask = mask;
                uctx32.uc_stack.ss_sp = CAST_DOWN_EXPLICIT(user32_addr_t, ua_fp);
                uctx32.uc_stack.ss_size = stack_size;

                if (oonstack) {
                        uctx32.uc_stack.ss_flags |= SS_ONSTACK;
                }
                uctx32.uc_link = 0;

                uctx32.uc_mcsize = thread_state64[sig_xstate].mcontext_size;

                uctx32.uc_mcontext = CAST_DOWN_EXPLICIT(user32_addr_t, ua_mctxp);

                if (copyout((caddr_t)&uctx32, ua_uctxp, sizeof(uctx32))) {
                        goto bad;
                }

                if (copyout((caddr_t)&mctx_store, ua_mctxp, thread_state32[sig_xstate].mcontext_size)) {
                        goto bad;
                }

                sinfo64.pad[0]  = tstate32->esp;
                sinfo64.si_addr = tstate32->eip;
        }

        switch (sig) {
        case SIGILL:
                switch (ut->uu_code) {
                case EXC_I386_INVOP:
                        sinfo64.si_code = ILL_ILLOPC;
                        break;
                default:
                        sinfo64.si_code = ILL_NOOP;
                }
                break;
        case SIGFPE:
#define FP_IE 0 /* Invalid operation */
#define FP_DE 1 /* Denormalized operand */
#define FP_ZE 2 /* Zero divide */
#define FP_OE 3 /* overflow */
#define FP_UE 4 /* underflow */
#define FP_PE 5 /* precision */
                if (ut->uu_code == EXC_I386_DIV) {
                        sinfo64.si_code = FPE_INTDIV;
                } else if (ut->uu_code == EXC_I386_INTO) {
                        sinfo64.si_code = FPE_INTOVF;
                } else if (ut->uu_subcode & (1 << FP_ZE)) {
                        sinfo64.si_code = FPE_FLTDIV;
                } else if (ut->uu_subcode & (1 << FP_OE)) {
                        sinfo64.si_code = FPE_FLTOVF;
                } else if (ut->uu_subcode & (1 << FP_UE)) {
                        sinfo64.si_code = FPE_FLTUND;
                } else if (ut->uu_subcode & (1 << FP_PE)) {
                        sinfo64.si_code = FPE_FLTRES;
                } else if (ut->uu_subcode & (1 << FP_IE)) {
                        sinfo64.si_code = FPE_FLTINV;
                } else {
                        sinfo64.si_code = FPE_NOOP;
                }
                break;
        case SIGBUS:
                sinfo64.si_code = BUS_ADRERR;
                sinfo64.si_addr = ua_cr2;
                break;
        case SIGTRAP:
                sinfo64.si_code = TRAP_BRKPT;
                break;
        case SIGSEGV:
                sinfo64.si_addr = ua_cr2;

                switch (ut->uu_code) {
                case EXC_I386_GPFLT:
                        /* CR2 is meaningless after GP fault */
                        /* XXX namespace clash! */
                        sinfo64.si_addr = 0ULL;
                        sinfo64.si_code = 0;
                        break;
                case KERN_PROTECTION_FAILURE:
                        sinfo64.si_code = SEGV_ACCERR;
                        break;
                case KERN_INVALID_ADDRESS:
                        sinfo64.si_code = SEGV_MAPERR;
                        break;
                default:
                        sinfo64.si_code = FPE_NOOP;
                }
                break;
        default:
        {
                int status_and_exitcode;

                /*
                 * All other signals need to fill out a minimum set of
                 * information for the siginfo structure passed into
                 * the signal handler, if SA_SIGINFO was specified.
                 *
                 * p->si_status actually contains both the status and
                 * the exit code; we save it off in its own variable
                 * for later breakdown.
                 */
                proc_lock(p);
                sinfo64.si_pid = p->si_pid;
                p->si_pid = 0;
                status_and_exitcode = p->si_status;
                p->si_status = 0;
                sinfo64.si_uid = p->si_uid;
                p->si_uid = 0;
                sinfo64.si_code = p->si_code;
                p->si_code = 0;
                proc_unlock(p);
                if (sinfo64.si_code == CLD_EXITED) {
                        if (WIFEXITED(status_and_exitcode)) {
                                sinfo64.si_code = CLD_EXITED;
                        } else if (WIFSIGNALED(status_and_exitcode)) {
                                if (WCOREDUMP(status_and_exitcode)) {
                                        sinfo64.si_code = CLD_DUMPED;
                                        status_and_exitcode = W_EXITCODE(status_and_exitcode, status_and_exitcode);
                                } else {
                                        sinfo64.si_code = CLD_KILLED;
                                        status_and_exitcode = W_EXITCODE(status_and_exitcode, status_and_exitcode);
                                }
                        }
                }
                /*
                 * The recorded status contains the exit code and the
                 * signal information, but the information to be passed
                 * in the siginfo to the handler is supposed to only
                 * contain the status, so we have to shift it out.
                 */
                sinfo64.si_status = (WEXITSTATUS(status_and_exitcode) & 0x00FFFFFF) | (((uint32_t)(p->p_xhighbits) << 24) & 0xFF000000);
                p->p_xhighbits = 0;
                break;
        }
        }
        if (proc_is64bit(p)) {
                user64_siginfo_t sinfo64_user64;

                bzero((caddr_t)&sinfo64_user64, sizeof(sinfo64_user64));

                siginfo_user_to_user64_x86(&sinfo64, &sinfo64_user64);

#if CONFIG_DTRACE
                bzero((caddr_t)&(ut->t_dtrace_siginfo), sizeof(ut->t_dtrace_siginfo));

                ut->t_dtrace_siginfo.si_signo = sinfo64.si_signo;
                ut->t_dtrace_siginfo.si_code = sinfo64.si_code;
                ut->t_dtrace_siginfo.si_pid = sinfo64.si_pid;
                ut->t_dtrace_siginfo.si_uid = sinfo64.si_uid;
                ut->t_dtrace_siginfo.si_status = sinfo64.si_status;
                /* XXX truncates faulting address to void * on K32  */
                ut->t_dtrace_siginfo.si_addr = CAST_DOWN(void *, sinfo64.si_addr);

                /* Fire DTrace proc:::fault probe when signal is generated by hardware. */
                switch (sig) {
                case SIGILL: case SIGBUS: case SIGSEGV: case SIGFPE: case SIGTRAP:
                        DTRACE_PROC2(fault, int, (int)(ut->uu_code), siginfo_t *, &(ut->t_dtrace_siginfo));
                        break;
                default:
                        break;
                }

                /* XXX truncates catcher address to uintptr_t */
                DTRACE_PROC3(signal__handle, int, sig, siginfo_t *, &(ut->t_dtrace_siginfo),
                    void (*)(void), CAST_DOWN(sig_t, ua_catcher));
#endif /* CONFIG_DTRACE */

                if (copyout((caddr_t)&sinfo64_user64, ua_sip, sizeof(sinfo64_user64))) {
                        goto bad;
                }

                if (sig_xstate & STATE64_FULL) {
                        flavor = x86_THREAD_FULL_STATE64;
                        state_count = x86_THREAD_FULL_STATE64_COUNT;
                } else {
                        flavor = x86_THREAD_STATE64;
                        state_count = x86_THREAD_STATE64_COUNT;
                }
                state = (void *)&mctxp->mctx_avx64.ss;
        } else {
                x86_thread_state32_t    *tstate32;
                user32_siginfo_t sinfo32;

                bzero((caddr_t)&sinfo32, sizeof(sinfo32));

                siginfo_user_to_user32_x86(&sinfo64, &sinfo32);

#if CONFIG_DTRACE
                bzero((caddr_t)&(ut->t_dtrace_siginfo), sizeof(ut->t_dtrace_siginfo));

                ut->t_dtrace_siginfo.si_signo = sinfo32.si_signo;
                ut->t_dtrace_siginfo.si_code = sinfo32.si_code;
                ut->t_dtrace_siginfo.si_pid = sinfo32.si_pid;
                ut->t_dtrace_siginfo.si_uid = sinfo32.si_uid;
                ut->t_dtrace_siginfo.si_status = sinfo32.si_status;
                ut->t_dtrace_siginfo.si_addr = CAST_DOWN(void *, sinfo32.si_addr);

                /* Fire DTrace proc:::fault probe when signal is generated by hardware. */
                switch (sig) {
                case SIGILL: case SIGBUS: case SIGSEGV: case SIGFPE: case SIGTRAP:
                        DTRACE_PROC2(fault, int, (int)(ut->uu_code), siginfo_t *, &(ut->t_dtrace_siginfo));
                        break;
                default:
                        break;
                }

                DTRACE_PROC3(signal__handle, int, sig, siginfo_t *, &(ut->t_dtrace_siginfo),
                    void (*)(void), CAST_DOWN(sig_t, ua_catcher));
#endif /* CONFIG_DTRACE */

                if (copyout((caddr_t)&sinfo32, ua_sip, sizeof(sinfo32))) {
                        goto bad;
                }

                tstate32 = &mctxp->mctx_avx32.ss;

                tstate32->eip = CAST_DOWN_EXPLICIT(user32_addr_t, trampact);
                tstate32->esp = CAST_DOWN_EXPLICIT(user32_addr_t, ua_fp);

                tstate32->eflags = get_eflags_exportmask();

                tstate32->cs = USER_CS;
                tstate32->ss = USER_DS;
                tstate32->ds = USER_DS;
                tstate32->es = USER_DS;
                tstate32->fs = NULL_SEG;
                tstate32->gs = USER_CTHREAD;

                flavor = x86_THREAD_STATE32;
                state_count = x86_THREAD_STATE32_COUNT;
                state = (void *)tstate32;
        }
        if (thread_setstatus(thread, flavor, (thread_state_t)state, state_count) != KERN_SUCCESS) {
                goto bad;
        }
        ml_fp_setvalid(FALSE);

        /* Tell the PAL layer about the signal */
        pal_set_signal_delivery( thread );

        proc_lock(p);

        return;

bad:

        proc_lock(p);
        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 */
        proc_unlock(p);
        psignal_locked(p, SIGILL);
        proc_lock(p);
        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.
 */

int
sigreturn(struct proc *p, struct sigreturn_args *uap, __unused int *retval)
{
        union {
                struct mcontext_avx32           mctx_avx32;
                struct mcontext_avx64           mctx_avx64;
                struct mcontext_avx64_full      mctx_avx64_full;
                struct mcontext_avx512_32       mctx_avx512_32;
                struct mcontext_avx512_64       mctx_avx512_64;
                struct mcontext_avx512_64_full  mctx_avx512_64_full;
        } mctx_store, *mctxp = &mctx_store;

        thread_t thread = current_thread();
        struct uthread * ut;
        struct sigacts *ps = p->p_sigacts;
        int     error;
        int     onstack = 0;

        mach_msg_type_number_t ts_count;
        unsigned int           ts_flavor;
        void                *  ts;
        mach_msg_type_number_t fs_count;
        unsigned int           fs_flavor;
        void                *  fs;
        int                    rval = EJUSTRETURN;
        xstate_t               sig_xstate;
        uint32_t            sigreturn_validation;
        user_addr_t         token_uctx;
        kern_return_t       kr;

        ut = (struct uthread *)get_bsdthread_info(thread);

        /*
         * If we are being asked to change the altstack flag on the thread, we
         * just set/reset it and return (the uap->uctx is not used).
         */
        if ((unsigned int)uap->infostyle == UC_SET_ALT_STACK) {
                ut->uu_sigstk.ss_flags |= SA_ONSTACK;
                return 0;
        } else if ((unsigned int)uap->infostyle == UC_RESET_ALT_STACK) {
                ut->uu_sigstk.ss_flags &= ~SA_ONSTACK;
                return 0;
        }

        bzero(mctxp, sizeof(*mctxp));

        sig_xstate = current_xstate();

        sigreturn_validation = atomic_load_explicit(
                &ps->ps_sigreturn_validation, memory_order_relaxed);
        token_uctx = uap->uctx;
        kr = machine_thread_siguctx_pointer_convert_to_user(thread, &token_uctx);
        assert(kr == KERN_SUCCESS);

        if (proc_is64bit(p)) {
                struct user_ucontext64  uctx64;
                user64_addr_t token;
                int task_has_ldt = thread_task_has_ldt(thread);

                if ((error = copyin(uap->uctx, (void *)&uctx64, sizeof(uctx64)))) {
                        return error;
                }

                onstack = uctx64.uc_onstack & 01;
                ut->uu_sigmask = uctx64.uc_sigmask & ~sigcantmask;

                if (task_has_ldt) {
                        ts_flavor = x86_THREAD_FULL_STATE64;
                        ts_count  = x86_THREAD_FULL_STATE64_COUNT;
                        fs = (void *)&mctxp->mctx_avx64_full.fs;
                        sig_xstate |= STATE64_FULL;
                } else {
                        ts_flavor = x86_THREAD_STATE64;
                        ts_count  = x86_THREAD_STATE64_COUNT;
                        fs = (void *)&mctxp->mctx_avx64.fs;
                }

                if ((error = copyin(uctx64.uc_mcontext64, (void *)mctxp, thread_state64[sig_xstate].mcontext_size))) {
                        return error;
                }

                ts = (void *)&mctxp->mctx_avx64.ss;

                fs_flavor = thread_state64[sig_xstate].flavor;
                fs_count  = thread_state64[sig_xstate].state_count;

                token = (user64_addr_t)token_uctx ^ (user64_addr_t)ps->ps_sigreturn_token;
                if ((user64_addr_t)uap->token != token) {
#if DEVELOPMENT || DEBUG
                        printf("process %s[%d] sigreturn token mismatch: received 0x%llx expected 0x%llx\n",
                            p->p_comm, p->p_pid, (user64_addr_t)uap->token, token);
#endif /* DEVELOPMENT || DEBUG */
                        if (sigreturn_validation != PS_SIGRETURN_VALIDATION_DISABLED) {
                                rval = EINVAL;
                        }
                }
        } else {
                struct user_ucontext32  uctx32;
                user32_addr_t token;

                if ((error = copyin(uap->uctx, (void *)&uctx32, sizeof(uctx32)))) {
                        return error;
                }

                if ((error = copyin(CAST_USER_ADDR_T(uctx32.uc_mcontext), (void *)mctxp, thread_state32[sig_xstate].mcontext_size))) {
                        return error;
                }

                onstack = uctx32.uc_onstack & 01;
                ut->uu_sigmask = uctx32.uc_sigmask & ~sigcantmask;

                ts_flavor = x86_THREAD_STATE32;
                ts_count  = x86_THREAD_STATE32_COUNT;
                ts = (void *)&mctxp->mctx_avx32.ss;

                fs_flavor = thread_state32[sig_xstate].flavor;
                fs_count  = thread_state32[sig_xstate].state_count;
                fs = (void *)&mctxp->mctx_avx32.fs;

                token = CAST_DOWN_EXPLICIT(user32_addr_t, uap->uctx) ^
                    CAST_DOWN_EXPLICIT(user32_addr_t, ps->ps_sigreturn_token);
                if ((user32_addr_t)uap->token != token) {
#if DEVELOPMENT || DEBUG
                        printf("process %s[%d] sigreturn token mismatch: received 0x%x expected 0x%x\n",
                            p->p_comm, p->p_pid, (user32_addr_t)uap->token, token);
#endif /* DEVELOPMENT || DEBUG */
                        if (sigreturn_validation != PS_SIGRETURN_VALIDATION_DISABLED) {
                                rval = EINVAL;
                        }
                }
        }

        if (onstack) {
                ut->uu_sigstk.ss_flags |= SA_ONSTACK;
        } else {
                ut->uu_sigstk.ss_flags &= ~SA_ONSTACK;
        }

        if (ut->uu_siglist & ~ut->uu_sigmask) {
                signal_setast(thread);
        }

        if (rval == EINVAL) {
                goto error_ret;
        }

        /*
         * thread_set_state() does all the needed checks for the passed in
         * content
         */
        if (thread_setstatus(thread, ts_flavor, ts, ts_count) != KERN_SUCCESS) {
                rval = EINVAL;
#if DEVELOPMENT || DEBUG
                printf("process %s[%d] sigreturn thread_setstatus error %d\n",
                    p->p_comm, p->p_pid, rval);
#endif /* DEVELOPMENT || DEBUG */
                goto error_ret;
        }

        ml_fp_setvalid(TRUE);

        if (thread_setstatus(thread, fs_flavor, fs, fs_count) != KERN_SUCCESS) {
                rval = EINVAL;
#if DEVELOPMENT || DEBUG
                printf("process %s[%d] sigreturn thread_setstatus error %d\n",
                    p->p_comm, p->p_pid, rval);
#endif /* DEVELOPMENT || DEBUG */
                goto error_ret;
        }
error_ret:
        return rval;
}


/*
 * machine_exception() performs machine-dependent translation
 * of a mach exception to a unix signal.
 */
int
machine_exception(int                           exception,
    mach_exception_code_t         code,
    __unused mach_exception_subcode_t      subcode)
{
        switch (exception) {
        case EXC_BAD_ACCESS:
                /* Map GP fault to SIGSEGV, otherwise defer to caller */
                if (code == EXC_I386_GPFLT) {
                        return SIGSEGV;
                }
                break;

        case EXC_BAD_INSTRUCTION:
                return SIGILL;

        case EXC_ARITHMETIC:
                return SIGFPE;

        case EXC_SOFTWARE:
                if (code == EXC_I386_BOUND) {
                        /*
                         * Map #BR, the Bound Range Exceeded exception, to
                         * SIGTRAP.
                         */
                        return SIGTRAP;
                }
                break;
        }

        return 0;
}