Sweden-Number/dlls/ntdll/unix/signal_arm64.c

/*
 * ARM64 signal handling routines
 *
 * Copyright 2010-2013 André Hentschel
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA
 */

#if 0
#pragma makedep unix
#endif

#ifdef __aarch64__

#include "config.h"
#include "wine/port.h"

#include <assert.h>
#include <pthread.h>
#include <signal.h>
#include <stdlib.h>
#include <stdarg.h>
#include <stdio.h>
#ifdef HAVE_UNISTD_H
# include <unistd.h>
#endif
#ifdef HAVE_SYS_PARAM_H
# include <sys/param.h>
#endif
#ifdef HAVE_SYSCALL_H
# include <syscall.h>
#else
# ifdef HAVE_SYS_SYSCALL_H
#  include <sys/syscall.h>
# endif
#endif
#ifdef HAVE_SYS_SIGNAL_H
# include <sys/signal.h>
#endif
#ifdef HAVE_SYS_UCONTEXT_H
# include <sys/ucontext.h>
#endif
#ifdef HAVE_LIBUNWIND
# define UNW_LOCAL_ONLY
# include <libunwind.h>
#endif

#define NONAMELESSUNION
#define NONAMELESSSTRUCT
#include "ntstatus.h"
#define WIN32_NO_STATUS
#include "windef.h"
#include "winnt.h"
#include "winternl.h"
#include "wine/exception.h"
#include "wine/asm.h"
#include "unix_private.h"
#include "wine/debug.h"

WINE_DEFAULT_DEBUG_CHANNEL(seh);

/***********************************************************************
 * signal context platform-specific definitions
 */
#ifdef linux

/* All Registers access - only for local access */
# define REG_sig(reg_name, context) ((context)->uc_mcontext.reg_name)
# define REGn_sig(reg_num, context) ((context)->uc_mcontext.regs[reg_num])

/* Special Registers access  */
# define SP_sig(context)            REG_sig(sp, context)    /* Stack pointer */
# define PC_sig(context)            REG_sig(pc, context)    /* Program counter */
# define PSTATE_sig(context)        REG_sig(pstate, context) /* Current State Register */
# define FP_sig(context)            REGn_sig(29, context)    /* Frame pointer */
# define LR_sig(context)            REGn_sig(30, context)    /* Link Register */

static struct _aarch64_ctx *get_extended_sigcontext( ucontext_t *sigcontext, unsigned int magic )
{
    struct _aarch64_ctx *ctx = (struct _aarch64_ctx *)sigcontext->uc_mcontext.__reserved;
    while ((char *)ctx < (char *)(&sigcontext->uc_mcontext + 1) && ctx->magic && ctx->size)
    {
        if (ctx->magic == magic) return ctx;
        ctx = (struct _aarch64_ctx *)((char *)ctx + ctx->size);
    }
    return NULL;
}

static struct fpsimd_context *get_fpsimd_context( ucontext_t *sigcontext )
{
    return (struct fpsimd_context *)get_extended_sigcontext( sigcontext, FPSIMD_MAGIC );
}

static DWORD64 get_fault_esr( ucontext_t *sigcontext )
{
    struct esr_context *esr = (struct esr_context *)get_extended_sigcontext( sigcontext, ESR_MAGIC );
    if (esr) return esr->esr;
    return 0;
}

#elif defined(__APPLE__)

/* All Registers access - only for local access */
# define REG_sig(reg_name, context) ((context)->uc_mcontext->__ss.__ ## reg_name)
# define REGn_sig(reg_num, context) ((context)->uc_mcontext->__ss.__x[reg_num])

/* Special Registers access  */
# define SP_sig(context)            REG_sig(sp, context)    /* Stack pointer */
# define PC_sig(context)            REG_sig(pc, context)    /* Program counter */
# define PSTATE_sig(context)        REG_sig(cpsr, context)  /* Current State Register */
# define FP_sig(context)            REG_sig(fp, context)    /* Frame pointer */
# define LR_sig(context)            REG_sig(lr, context)    /* Link Register */

static DWORD64 get_fault_esr( ucontext_t *sigcontext )
{
    return sigcontext->uc_mcontext->__es.__esr;
}

#endif /* linux */

static pthread_key_t teb_key;

struct syscall_frame
{
    ULONG64 x29;
    ULONG64 thunk_addr;
    ULONG64 x0, x1, x2, x3, x4, x5, x6, x7, x19, x20, x21, x22, x23, x24, x25, x26, x27, x28;
    ULONG64 thunk_x29;
    ULONG64 ret_addr;
};

struct arm64_thread_data
{
    void                 *exit_frame;    /* 02f0 exit frame pointer */
    struct syscall_frame *syscall_frame; /* 02f8 frame pointer on syscall entry */
    CONTEXT              *context;       /* 0300 context to set with SIGUSR2 */
};

C_ASSERT( sizeof(struct arm64_thread_data) <= sizeof(((struct ntdll_thread_data *)0)->cpu_data) );
C_ASSERT( offsetof( TEB, GdiTebBatch ) + offsetof( struct arm64_thread_data, exit_frame ) == 0x2f0 );
C_ASSERT( offsetof( TEB, GdiTebBatch ) + offsetof( struct arm64_thread_data, syscall_frame ) == 0x2f8 );

static inline struct arm64_thread_data *arm64_thread_data(void)
{
    return (struct arm64_thread_data *)ntdll_get_thread_data()->cpu_data;
}

void *get_syscall_frame(void)
{
    return arm64_thread_data()->syscall_frame;
}

void set_syscall_frame(void *frame)
{
    arm64_thread_data()->syscall_frame = frame;
}

extern void raise_func_trampoline( EXCEPTION_RECORD *rec, CONTEXT *context, void *dispatcher );

/***********************************************************************
 *           unwind_builtin_dll
 *
 * Equivalent of RtlVirtualUnwind for builtin modules.
 */
NTSTATUS CDECL unwind_builtin_dll( ULONG type, DISPATCHER_CONTEXT *dispatch, CONTEXT *context )
{
#ifdef HAVE_LIBUNWIND
    ULONG_PTR ip = context->Pc;
    unw_context_t unw_context;
    unw_cursor_t cursor;
    unw_proc_info_t info;
    int rc;

#ifdef __APPLE__
    rc = unw_getcontext( &unw_context );
    if (rc == UNW_ESUCCESS)
        rc = unw_init_local( &cursor, &unw_context );
    if (rc == UNW_ESUCCESS)
    {
        int i;
        for (i = 0; i <= 28; i++)
            unw_set_reg( &cursor, UNW_ARM64_X0 + i, context->u.X[i] );
        unw_set_reg( &cursor, UNW_ARM64_FP, context->u.s.Fp );
        unw_set_reg( &cursor, UNW_ARM64_LR, context->u.s.Lr );
        unw_set_reg( &cursor, UNW_ARM64_SP, context->Sp );
        unw_set_reg( &cursor, UNW_REG_IP,   context->Pc );
    }
#else
    memcpy( unw_context.uc_mcontext.regs, context->u.X, sizeof(context->u.X) );
    unw_context.uc_mcontext.sp = context->Sp;
    unw_context.uc_mcontext.pc = context->Pc;

    rc = unw_init_local( &cursor, &unw_context );
#endif
    if (rc != UNW_ESUCCESS)
    {
        WARN( "setup failed: %d\n", rc );
        return STATUS_INVALID_DISPOSITION;
    }
    rc = unw_get_proc_info( &cursor, &info );
    if (rc != UNW_ESUCCESS && rc != -UNW_ENOINFO)
    {
        WARN( "failed to get info: %d\n", rc );
        return STATUS_INVALID_DISPOSITION;
    }
    if (rc == -UNW_ENOINFO || ip < info.start_ip || ip > info.end_ip)
    {
        TRACE( "no info found for %lx ip %lx-%lx, assuming leaf function\n",
               ip, info.start_ip, info.end_ip );
        dispatch->LanguageHandler = NULL;
        dispatch->EstablisherFrame = context->Sp;
        context->Pc = context->u.s.Lr;
        context->Sp = context->Sp + sizeof(ULONG64);
        context->ContextFlags |= CONTEXT_UNWOUND_TO_CALL;
        return STATUS_SUCCESS;
    }

    TRACE( "ip %#lx function %#lx-%#lx personality %#lx lsda %#lx fde %#lx\n",
           ip, (unsigned long)info.start_ip, (unsigned long)info.end_ip, (unsigned long)info.handler,
           (unsigned long)info.lsda, (unsigned long)info.unwind_info );

    rc = unw_step( &cursor );
    if (rc < 0)
    {
        WARN( "failed to unwind: %d %d\n", rc, UNW_ENOINFO );
        return STATUS_INVALID_DISPOSITION;
    }

    dispatch->LanguageHandler  = (void *)info.handler;
    dispatch->HandlerData      = (void *)info.lsda;
    dispatch->EstablisherFrame = context->Sp;
#ifdef __APPLE__
    {
        int i;
        for (i = 0; i <= 28; i++)
            unw_get_reg( &cursor, UNW_ARM64_X0 + i, (unw_word_t *)&context->u.X[i] );
    }
    unw_get_reg( &cursor, UNW_ARM64_FP,    (unw_word_t *)&context->u.s.Fp );
    unw_get_reg( &cursor, UNW_ARM64_X30,   (unw_word_t *)&context->u.s.Lr );
    unw_get_reg( &cursor, UNW_ARM64_SP,    (unw_word_t *)&context->Sp );
#else
    unw_get_reg( &cursor, UNW_AARCH64_X0,  (unw_word_t *)&context->u.s.X0 );
    unw_get_reg( &cursor, UNW_AARCH64_X1,  (unw_word_t *)&context->u.s.X1 );
    unw_get_reg( &cursor, UNW_AARCH64_X2,  (unw_word_t *)&context->u.s.X2 );
    unw_get_reg( &cursor, UNW_AARCH64_X3,  (unw_word_t *)&context->u.s.X3 );
    unw_get_reg( &cursor, UNW_AARCH64_X4,  (unw_word_t *)&context->u.s.X4 );
    unw_get_reg( &cursor, UNW_AARCH64_X5,  (unw_word_t *)&context->u.s.X5 );
    unw_get_reg( &cursor, UNW_AARCH64_X6,  (unw_word_t *)&context->u.s.X6 );
    unw_get_reg( &cursor, UNW_AARCH64_X7,  (unw_word_t *)&context->u.s.X7 );
    unw_get_reg( &cursor, UNW_AARCH64_X8,  (unw_word_t *)&context->u.s.X8 );
    unw_get_reg( &cursor, UNW_AARCH64_X9,  (unw_word_t *)&context->u.s.X9 );
    unw_get_reg( &cursor, UNW_AARCH64_X10, (unw_word_t *)&context->u.s.X10 );
    unw_get_reg( &cursor, UNW_AARCH64_X11, (unw_word_t *)&context->u.s.X11 );
    unw_get_reg( &cursor, UNW_AARCH64_X12, (unw_word_t *)&context->u.s.X12 );
    unw_get_reg( &cursor, UNW_AARCH64_X13, (unw_word_t *)&context->u.s.X13 );
    unw_get_reg( &cursor, UNW_AARCH64_X14, (unw_word_t *)&context->u.s.X14 );
    unw_get_reg( &cursor, UNW_AARCH64_X15, (unw_word_t *)&context->u.s.X15 );
    unw_get_reg( &cursor, UNW_AARCH64_X16, (unw_word_t *)&context->u.s.X16 );
    unw_get_reg( &cursor, UNW_AARCH64_X17, (unw_word_t *)&context->u.s.X17 );
    unw_get_reg( &cursor, UNW_AARCH64_X18, (unw_word_t *)&context->u.s.X18 );
    unw_get_reg( &cursor, UNW_AARCH64_X19, (unw_word_t *)&context->u.s.X19 );
    unw_get_reg( &cursor, UNW_AARCH64_X20, (unw_word_t *)&context->u.s.X20 );
    unw_get_reg( &cursor, UNW_AARCH64_X21, (unw_word_t *)&context->u.s.X21 );
    unw_get_reg( &cursor, UNW_AARCH64_X22, (unw_word_t *)&context->u.s.X22 );
    unw_get_reg( &cursor, UNW_AARCH64_X23, (unw_word_t *)&context->u.s.X23 );
    unw_get_reg( &cursor, UNW_AARCH64_X24, (unw_word_t *)&context->u.s.X24 );
    unw_get_reg( &cursor, UNW_AARCH64_X25, (unw_word_t *)&context->u.s.X25 );
    unw_get_reg( &cursor, UNW_AARCH64_X26, (unw_word_t *)&context->u.s.X26 );
    unw_get_reg( &cursor, UNW_AARCH64_X27, (unw_word_t *)&context->u.s.X27 );
    unw_get_reg( &cursor, UNW_AARCH64_X28, (unw_word_t *)&context->u.s.X28 );
    unw_get_reg( &cursor, UNW_AARCH64_X29, (unw_word_t *)&context->u.s.Fp );
    unw_get_reg( &cursor, UNW_AARCH64_X30, (unw_word_t *)&context->u.s.Lr );
    unw_get_reg( &cursor, UNW_AARCH64_SP,  (unw_word_t *)&context->Sp );
#endif
    unw_get_reg( &cursor, UNW_REG_IP,      (unw_word_t *)&context->Pc );
    context->ContextFlags |= CONTEXT_UNWOUND_TO_CALL;

    if (info.start_ip == (unw_word_t)raise_func_trampoline) {
        /* raise_func_trampoline has a full CONTEXT stored on the stack;
         * restore the original Lr value from there. The function we unwind
         * to might be a leaf function that hasn't backed up its own original
         * Lr value on the stack.
         * We could also just restore the full context here without doing
         * unw_step at all. */
        const CONTEXT *next_ctx = (const CONTEXT *) dispatch->EstablisherFrame;
        context->u.s.Lr = next_ctx->u.s.Lr;
    }

    TRACE( "next function pc=%016lx%s\n", context->Pc, rc ? "" : " (last frame)" );
    TRACE("  x0=%016lx  x1=%016lx  x2=%016lx  x3=%016lx\n",
          context->u.s.X0, context->u.s.X1, context->u.s.X2, context->u.s.X3 );
    TRACE("  x4=%016lx  x5=%016lx  x6=%016lx  x7=%016lx\n",
          context->u.s.X4, context->u.s.X5, context->u.s.X6, context->u.s.X7 );
    TRACE("  x8=%016lx  x9=%016lx x10=%016lx x11=%016lx\n",
          context->u.s.X8, context->u.s.X9, context->u.s.X10, context->u.s.X11 );
    TRACE(" x12=%016lx x13=%016lx x14=%016lx x15=%016lx\n",
          context->u.s.X12, context->u.s.X13, context->u.s.X14, context->u.s.X15 );
    TRACE(" x16=%016lx x17=%016lx x18=%016lx x19=%016lx\n",
          context->u.s.X16, context->u.s.X17, context->u.s.X18, context->u.s.X19 );
    TRACE(" x20=%016lx x21=%016lx x22=%016lx x23=%016lx\n",
          context->u.s.X20, context->u.s.X21, context->u.s.X22, context->u.s.X23 );
    TRACE(" x24=%016lx x25=%016lx x26=%016lx x27=%016lx\n",
          context->u.s.X24, context->u.s.X25, context->u.s.X26, context->u.s.X27 );
    TRACE(" x28=%016lx  fp=%016lx  lr=%016lx  sp=%016lx\n",
          context->u.s.X28, context->u.s.Fp, context->u.s.Lr, context->Sp );
    return STATUS_SUCCESS;
#else
    return STATUS_INVALID_DISPOSITION;
#endif
}


/***********************************************************************
 *           save_context
 *
 * Set the register values from a sigcontext.
 */
static void save_context( CONTEXT *context, const ucontext_t *sigcontext )
{
    DWORD i;

    context->ContextFlags = (CONTEXT_FULL & ~CONTEXT_FLOATING_POINT) |
                             CONTEXT_ARM64;
    context->u.s.Fp = FP_sig(sigcontext);     /* Frame pointer */
    context->u.s.Lr = LR_sig(sigcontext);     /* Link register */
    context->Sp     = SP_sig(sigcontext);     /* Stack pointer */
    context->Pc     = PC_sig(sigcontext);     /* Program Counter */
    context->Cpsr   = PSTATE_sig(sigcontext); /* Current State Register */
    for (i = 0; i <= 28; i++) context->u.X[i] = REGn_sig( i, sigcontext );
}


/***********************************************************************
 *           restore_context
 *
 * Build a sigcontext from the register values.
 */
static void restore_context( const CONTEXT *context, ucontext_t *sigcontext )
{
    DWORD i;

    FP_sig(sigcontext)     = context->u.s.Fp; /* Frame pointer */
    LR_sig(sigcontext)     = context->u.s.Lr; /* Link register */
    SP_sig(sigcontext)     = context->Sp;     /* Stack pointer */
    PC_sig(sigcontext)     = context->Pc;     /* Program Counter */
    PSTATE_sig(sigcontext) = context->Cpsr;   /* Current State Register */
    for (i = 0; i <= 28; i++) REGn_sig( i, sigcontext ) = context->u.X[i];
}


/***********************************************************************
 *           save_fpu
 *
 * Set the FPU context from a sigcontext.
 */
static void save_fpu( CONTEXT *context, ucontext_t *sigcontext )
{
#ifdef linux
    struct fpsimd_context *fp = get_fpsimd_context( sigcontext );

    if (!fp) return;
    context->ContextFlags |= CONTEXT_FLOATING_POINT;
    context->Fpcr = fp->fpcr;
    context->Fpsr = fp->fpsr;
    memcpy( context->V, fp->vregs, sizeof(context->V) );
#elif defined(__APPLE__)
    context->ContextFlags |= CONTEXT_FLOATING_POINT;
    context->Fpcr = sigcontext->uc_mcontext->__ns.__fpcr;
    context->Fpsr = sigcontext->uc_mcontext->__ns.__fpsr;
    memcpy( context->V, sigcontext->uc_mcontext->__ns.__v, sizeof(context->V) );
#endif
}


/***********************************************************************
 *           restore_fpu
 *
 * Restore the FPU context to a sigcontext.
 */
static void restore_fpu( CONTEXT *context, ucontext_t *sigcontext )
{
#ifdef linux
    struct fpsimd_context *fp = get_fpsimd_context( sigcontext );

    if (!fp) return;
    fp->fpcr = context->Fpcr;
    fp->fpsr = context->Fpsr;
    memcpy( fp->vregs, context->V, sizeof(fp->vregs) );
#elif defined(__APPLE__)
    sigcontext->uc_mcontext->__ns.__fpcr = context->Fpcr;
    sigcontext->uc_mcontext->__ns.__fpsr = context->Fpsr;
    memcpy( sigcontext->uc_mcontext->__ns.__v, context->V, sizeof(context->V) );
#endif
}


/***********************************************************************
 *           get_server_context_flags
 *
 * Convert CPU-specific flags to generic server flags
 */
static unsigned int get_server_context_flags( DWORD flags )
{
    unsigned int ret = 0;

    flags &= ~CONTEXT_ARM64;  /* get rid of CPU id */
    if (flags & CONTEXT_CONTROL) ret |= SERVER_CTX_CONTROL;
    if (flags & CONTEXT_INTEGER) ret |= SERVER_CTX_INTEGER;
    if (flags & CONTEXT_FLOATING_POINT) ret |= SERVER_CTX_FLOATING_POINT;
    if (flags & CONTEXT_DEBUG_REGISTERS) ret |= SERVER_CTX_DEBUG_REGISTERS;
    return ret;
}


/***********************************************************************
 *           context_to_server
 *
 * Convert a register context to the server format.
 */
NTSTATUS context_to_server( context_t *to, const CONTEXT *from )
{
    DWORD i, flags = from->ContextFlags & ~CONTEXT_ARM64;  /* get rid of CPU id */

    memset( to, 0, sizeof(*to) );
    to->cpu = CPU_ARM64;

    if (flags & CONTEXT_CONTROL)
    {
        to->flags |= SERVER_CTX_CONTROL;
        to->integer.arm64_regs.x[29] = from->u.s.Fp;
        to->integer.arm64_regs.x[30] = from->u.s.Lr;
        to->ctl.arm64_regs.sp     = from->Sp;
        to->ctl.arm64_regs.pc     = from->Pc;
        to->ctl.arm64_regs.pstate = from->Cpsr;
    }
    if (flags & CONTEXT_INTEGER)
    {
        to->flags |= SERVER_CTX_INTEGER;
        for (i = 0; i <= 28; i++) to->integer.arm64_regs.x[i] = from->u.X[i];
    }
    if (flags & CONTEXT_FLOATING_POINT)
    {
        to->flags |= SERVER_CTX_FLOATING_POINT;
        for (i = 0; i < 32; i++)
        {
            to->fp.arm64_regs.q[i].low = from->V[i].s.Low;
            to->fp.arm64_regs.q[i].high = from->V[i].s.High;
        }
        to->fp.arm64_regs.fpcr = from->Fpcr;
        to->fp.arm64_regs.fpsr = from->Fpsr;
    }
    if (flags & CONTEXT_DEBUG_REGISTERS)
    {
        to->flags |= SERVER_CTX_DEBUG_REGISTERS;
        for (i = 0; i < ARM64_MAX_BREAKPOINTS; i++) to->debug.arm64_regs.bcr[i] = from->Bcr[i];
        for (i = 0; i < ARM64_MAX_BREAKPOINTS; i++) to->debug.arm64_regs.bvr[i] = from->Bvr[i];
        for (i = 0; i < ARM64_MAX_WATCHPOINTS; i++) to->debug.arm64_regs.wcr[i] = from->Wcr[i];
        for (i = 0; i < ARM64_MAX_WATCHPOINTS; i++) to->debug.arm64_regs.wvr[i] = from->Wvr[i];
    }
    return STATUS_SUCCESS;
}


/***********************************************************************
 *           context_from_server
 *
 * Convert a register context from the server format.
 */
NTSTATUS context_from_server( CONTEXT *to, const context_t *from )
{
    DWORD i;

    if (from->cpu != CPU_ARM64) return STATUS_INVALID_PARAMETER;

    to->ContextFlags = CONTEXT_ARM64;
    if (from->flags & SERVER_CTX_CONTROL)
    {
        to->ContextFlags |= CONTEXT_CONTROL;
        to->u.s.Fp = from->integer.arm64_regs.x[29];
        to->u.s.Lr = from->integer.arm64_regs.x[30];
        to->Sp     = from->ctl.arm64_regs.sp;
        to->Pc     = from->ctl.arm64_regs.pc;
        to->Cpsr   = from->ctl.arm64_regs.pstate;
    }
    if (from->flags & SERVER_CTX_INTEGER)
    {
        to->ContextFlags |= CONTEXT_INTEGER;
        for (i = 0; i <= 28; i++) to->u.X[i] = from->integer.arm64_regs.x[i];
    }
    if (from->flags & SERVER_CTX_FLOATING_POINT)
    {
        to->ContextFlags |= CONTEXT_FLOATING_POINT;
        for (i = 0; i < 32; i++)
        {
            to->V[i].s.Low = from->fp.arm64_regs.q[i].low;
            to->V[i].s.High = from->fp.arm64_regs.q[i].high;
        }
        to->Fpcr = from->fp.arm64_regs.fpcr;
        to->Fpsr = from->fp.arm64_regs.fpsr;
    }
    if (from->flags & SERVER_CTX_DEBUG_REGISTERS)
    {
        to->ContextFlags |= CONTEXT_DEBUG_REGISTERS;
        for (i = 0; i < ARM64_MAX_BREAKPOINTS; i++) to->Bcr[i] = from->debug.arm64_regs.bcr[i];
        for (i = 0; i < ARM64_MAX_BREAKPOINTS; i++) to->Bvr[i] = from->debug.arm64_regs.bvr[i];
        for (i = 0; i < ARM64_MAX_WATCHPOINTS; i++) to->Wcr[i] = from->debug.arm64_regs.wcr[i];
        for (i = 0; i < ARM64_MAX_WATCHPOINTS; i++) to->Wvr[i] = from->debug.arm64_regs.wvr[i];
    }
    return STATUS_SUCCESS;
}


/***********************************************************************
 *              NtSetContextThread  (NTDLL.@)
 *              ZwSetContextThread  (NTDLL.@)
 */
NTSTATUS WINAPI NtSetContextThread( HANDLE handle, const CONTEXT *context )
{
    NTSTATUS ret = STATUS_SUCCESS;
    BOOL self = (handle == GetCurrentThread());

    if (self && (context->ContextFlags & (CONTEXT_DEBUG_REGISTERS & ~CONTEXT_ARM64))) self = FALSE;

    if (!self)
    {
        context_t server_context;
        context_to_server( &server_context, context );
        ret = set_thread_context( handle, &server_context, &self );
    }
    if (self && ret == STATUS_SUCCESS)
    {
        arm64_thread_data()->syscall_frame = NULL;
        InterlockedExchangePointer( (void **)&arm64_thread_data()->context, (void *)context );
        raise( SIGUSR2 );
    }
    return ret;
}


/***********************************************************************
 *              NtGetContextThread  (NTDLL.@)
 *              ZwGetContextThread  (NTDLL.@)
 */
NTSTATUS WINAPI NtGetContextThread( HANDLE handle, CONTEXT *context )
{
    NTSTATUS ret;
    struct syscall_frame *frame = arm64_thread_data()->syscall_frame;
    DWORD needed_flags = context->ContextFlags & ~CONTEXT_ARM64;
    BOOL self = (handle == GetCurrentThread());

    if (!self)
    {
        context_t server_context;
        unsigned int server_flags = get_server_context_flags( context->ContextFlags );

        if ((ret = get_thread_context( handle, &server_context, server_flags, &self ))) return ret;
        if ((ret = context_from_server( context, &server_context ))) return ret;
        needed_flags &= ~context->ContextFlags;
    }

    if (self)
    {
        if (needed_flags & CONTEXT_INTEGER)
        {
            memset( context->u.X, 0, sizeof(context->u.X[0]) * 18 );
            context->u.X[18] = (DWORD64)NtCurrentTeb();
            memcpy( context->u.X + 19, &frame->x19, sizeof(context->u.X[0]) * 10 );
            context->ContextFlags |= CONTEXT_INTEGER;
        }
        if (needed_flags & CONTEXT_CONTROL)
        {
            context->u.s.Fp  = frame->x29;
            context->u.s.Lr  = frame->ret_addr;
            context->Sp      = (ULONG64)&frame->thunk_x29;
            context->Pc      = frame->thunk_addr;
            context->Cpsr    = 0;
            context->ContextFlags |= CONTEXT_CONTROL;
        }
        if (needed_flags & CONTEXT_FLOATING_POINT) FIXME( "floating point not supported\n" );
        if (needed_flags & CONTEXT_DEBUG_REGISTERS) FIXME( "debug registers not supported\n" );
    }
    return STATUS_SUCCESS;
}


/* Note, unwind_builtin_dll above has hardcoded assumptions on how this
 * function stores things on the stack; if modified, modify that one in
 * sync as well. */
__ASM_GLOBAL_FUNC( raise_func_trampoline,
                   "stp x29, x30, [sp, #-0x30]!\n\t"
                   __ASM_CFI(".cfi_def_cfa_offset 48\n\t")
                   __ASM_CFI(".cfi_offset 29, -48\n\t")
                   __ASM_CFI(".cfi_offset 30, -40\n\t")
                   "stp x0,  x1,  [sp, #0x10]\n\t"
                   "str x2,       [sp, #0x20]\n\t"
                   "mov x29, sp\n\t"
                   __ASM_CFI(".cfi_def_cfa_register 29\n\t")
                   __ASM_CFI(".cfi_remember_state\n\t")

                   /* Memcpy the context onto the stack */
                   "sub sp, sp, #0x390\n\t"
                   "mov x0,  sp\n\t"
                   "mov x2,  #0x390\n\t"
                   "bl " __ASM_NAME("memcpy") "\n\t"
                   __ASM_CFI(".cfi_def_cfa 31, 0\n\t")
                   __ASM_CFI(".cfi_escape 0x0f,0x04,0x8f,0x80,0x02,0x06\n\t") /* CFA, DW_OP_breg31 + 0x100, DW_OP_deref */
                   __ASM_CFI(".cfi_escape 0x10,0x13,0x03,0x8f,0xa0,0x01\n\t") /* x19, DW_OP_breg31 + 0xA0 */
                   __ASM_CFI(".cfi_escape 0x10,0x14,0x03,0x8f,0xa8,0x01\n\t") /* x20 */
                   __ASM_CFI(".cfi_escape 0x10,0x15,0x03,0x8f,0xb0,0x01\n\t") /* x21 */
                   __ASM_CFI(".cfi_escape 0x10,0x16,0x03,0x8f,0xb8,0x01\n\t") /* x22 */
                   __ASM_CFI(".cfi_escape 0x10,0x17,0x03,0x8f,0xc0,0x01\n\t") /* x23 */
                   __ASM_CFI(".cfi_escape 0x10,0x18,0x03,0x8f,0xc8,0x01\n\t") /* x24 */
                   __ASM_CFI(".cfi_escape 0x10,0x19,0x03,0x8f,0xd0,0x01\n\t") /* x25 */
                   __ASM_CFI(".cfi_escape 0x10,0x1a,0x03,0x8f,0xd8,0x01\n\t") /* x26 */
                   __ASM_CFI(".cfi_escape 0x10,0x1b,0x03,0x8f,0xe0,0x01\n\t") /* x27 */
                   __ASM_CFI(".cfi_escape 0x10,0x1c,0x03,0x8f,0xe8,0x01\n\t") /* x28 */
                   __ASM_CFI(".cfi_escape 0x10,0x1d,0x03,0x8f,0xf0,0x01\n\t") /* x29 */
                   __ASM_CFI(".cfi_escape 0x10,0x1e,0x03,0x8f,0x88,0x02\n\t") /* x30 = pc */
                   __ASM_CFI(".cfi_escape 0x10,0x48,0x03,0x8f,0x90,0x03\n\t") /* d8  */
                   __ASM_CFI(".cfi_escape 0x10,0x49,0x03,0x8f,0x98,0x03\n\t") /* d9  */
                   __ASM_CFI(".cfi_escape 0x10,0x4a,0x03,0x8f,0xa0,0x03\n\t") /* d10 */
                   __ASM_CFI(".cfi_escape 0x10,0x4b,0x03,0x8f,0xa8,0x03\n\t") /* d11 */
                   __ASM_CFI(".cfi_escape 0x10,0x4c,0x03,0x8f,0xb0,0x03\n\t") /* d12 */
                   __ASM_CFI(".cfi_escape 0x10,0x4d,0x03,0x8f,0xb8,0x03\n\t") /* d13 */
                   __ASM_CFI(".cfi_escape 0x10,0x4e,0x03,0x8f,0xc0,0x03\n\t") /* d14 */
                   __ASM_CFI(".cfi_escape 0x10,0x4f,0x03,0x8f,0xc8,0x03\n\t") /* d15 */
                   "ldp x0,  x1,  [x29, #0x10]\n\t"
                   "ldr x2,       [x29, #0x20]\n\t"
                   "blr x2\n\t"
                   __ASM_CFI(".cfi_restore_state\n\t")
                   "brk #1")

/***********************************************************************
 *           setup_exception
 *
 * Modify the signal context to call the exception raise function.
 */
static void setup_exception( ucontext_t *sigcontext, EXCEPTION_RECORD *rec )
{
    struct
    {
        CONTEXT           context;
        EXCEPTION_RECORD  rec;
        void             *redzone[3];
    } *stack;

    void *stack_ptr = (void *)(SP_sig(sigcontext) & ~15);
    CONTEXT context;
    NTSTATUS status;

    rec->ExceptionAddress = (void *)PC_sig(sigcontext);
    save_context( &context, sigcontext );
    save_fpu( &context, sigcontext );
    if (rec->ExceptionCode == EXCEPTION_BREAKPOINT) context.Pc += 4;

    status = send_debug_event( rec, &context, TRUE );
    if (status == DBG_CONTINUE || status == DBG_EXCEPTION_HANDLED)
    {
        restore_context( &context, sigcontext );
        return;
    }

    stack = virtual_setup_exception( stack_ptr, (sizeof(*stack) + 15) & ~15, rec );
    stack->rec = *rec;
    stack->context = context;

    SP_sig(sigcontext) = (ULONG_PTR)stack;
    LR_sig(sigcontext) = PC_sig(sigcontext);
    PC_sig(sigcontext) = (ULONG_PTR)raise_func_trampoline;
    REGn_sig(0, sigcontext) = (ULONG_PTR)&stack->rec;  /* first arg for KiUserExceptionDispatcher */
    REGn_sig(1, sigcontext) = (ULONG_PTR)&stack->context; /* second arg for KiUserExceptionDispatcher */
    REGn_sig(2, sigcontext) = (ULONG_PTR)pKiUserExceptionDispatcher; /* dispatcher arg for raise_func_trampoline */
    REGn_sig(18, sigcontext) = (ULONG_PTR)NtCurrentTeb();
}


/***********************************************************************
 *           call_user_apc_dispatcher
 */
__ASM_GLOBAL_FUNC( call_user_apc_dispatcher,
                   "mov x19, x0\n\t"             /* context */
                   "mov x20, x1\n\t"             /* ctx */
                   "mov x21, x2\n\t"             /* arg1 */
                   "mov x22, x3\n\t"             /* arg2 */
                   "mov x23, x4\n\t"             /* func */
                   "mov x24, x5\n\t"             /* dispatcher */
                   "bl " __ASM_NAME("NtCurrentTeb") "\n\t"
                   "add x25, x0, #0x2f8\n\t"     /* arm64_thread_data()->syscall_frame */
                   "cbz x19, 1f\n\t"
                   "ldr x0, [x19, #0x100]\n\t"   /* context.Sp */
                   "sub x0, x0, #0x430\n\t"      /* sizeof(CONTEXT) + offsetof(frame,thunk_x29) */
                   "str xzr, [x25]\n\t"
                   "mov sp, x0\n\t"
                   "b 2f\n"
                   "1:\tldr x0, [x25]\n\t"
                   "sub sp, x0, #0x390\n\t"
                   "mov w2, #0x400000\n\t"       /* context.ContextFlags = CONTEXT_FULL */
                   "movk w2, #7\n\t"
                   "str w2, [sp]\n\t"
                   "mov x1, sp\n\t"
                   "mov x0, #~1\n\t"
                   "bl " __ASM_NAME("NtGetContextThread") "\n\t"
                   "mov w2, #0xc0\n\t"           /* context.X0 = STATUS_USER_APC */
                   "str x2, [sp, #8]\n\t"
                   "str xzr, [x25]\n\t"
                   "mov x0, sp\n"                /* context */
                   "2:\tldr lr, [x0, #0xf8]\n\t" /* context.Lr */
                   "mov x1, x20\n\t"             /* ctx */
                   "mov x2, x21\n\t"             /* arg1 */
                   "mov x3, x22\n\t"             /* arg2 */
                   "mov x4, x23\n\t"             /* func */
                   "br x24" )


/***********************************************************************
 *           call_raise_user_exception_dispatcher
 */
__ASM_GLOBAL_FUNC( call_raise_user_exception_dispatcher,
                   "mov x2, x0\n\t"  /* dispatcher */
                   "b " __ASM_NAME("call_user_exception_dispatcher") )


/***********************************************************************
 *           call_user_exception_dispatcher
 */
__ASM_GLOBAL_FUNC( call_user_exception_dispatcher,
                   "mov x19, x0\n\t"
                   "mov x20, x1\n\t"
                   "mov x21, x2\n\t"
                   "bl " __ASM_NAME("NtCurrentTeb") "\n\t"
                   "add x4, x0, #0x2f8\n\t"        /* arm64_thread_data()->syscall_frame */
                   "ldr x5, [x4]\n\t"
                   "str xzr, [x4]\n\t"
                   "mov x0, x19\n\t"
                   "mov x1, x20\n\t"
                   "mov x2, x21\n\t"
                   "ldp x19, x20, [x5, #80]\n\t"   /* frame->x19,x20 */
                   "ldp x21, x22, [x5, #96]\n\t"   /* frame->x21,x22 */
                   "ldp x23, x24, [x5, #112]\n\t"  /* frame->x23,x24 */
                   "ldp x25, x26, [x5, #128]\n\t"  /* frame->x25,x26 */
                   "ldp x27, x28, [x5, #144]\n\t"  /* frame->x27,x28 */
                   "ldp x29, x30, [x5, #160]\n\t"  /* frame->thunk_x29,ret_addr */
                   "add sp, x5, #176\n\t"
                   "br x2" )


/***********************************************************************
 *           handle_syscall_fault
 *
 * Handle a page fault happening during a system call.
 */
static BOOL handle_syscall_fault( ucontext_t *context, EXCEPTION_RECORD *rec )
{
    struct syscall_frame *frame = arm64_thread_data()->syscall_frame;
    __WINE_FRAME *wine_frame = (__WINE_FRAME *)NtCurrentTeb()->Tib.ExceptionList;
    DWORD i;

    if (!frame) return FALSE;

    TRACE( "code=%x flags=%x addr=%p pc=%p tid=%04x\n",
           rec->ExceptionCode, rec->ExceptionFlags, rec->ExceptionAddress,
           (void *)PC_sig(context), GetCurrentThreadId() );
    for (i = 0; i < rec->NumberParameters; i++)
        TRACE( " info[%d]=%016lx\n", i, rec->ExceptionInformation[i] );

    TRACE("  x0=%016lx  x1=%016lx  x2=%016lx  x3=%016lx\n",
          (DWORD64)REGn_sig(0, context), (DWORD64)REGn_sig(1, context),
          (DWORD64)REGn_sig(2, context), (DWORD64)REGn_sig(3, context) );
    TRACE("  x4=%016lx  x5=%016lx  x6=%016lx  x7=%016lx\n",
          (DWORD64)REGn_sig(4, context), (DWORD64)REGn_sig(5, context),
          (DWORD64)REGn_sig(6, context), (DWORD64)REGn_sig(7, context) );
    TRACE("  x8=%016lx  x9=%016lx x10=%016lx x11=%016lx\n",
          (DWORD64)REGn_sig(8, context), (DWORD64)REGn_sig(9, context),
          (DWORD64)REGn_sig(10, context), (DWORD64)REGn_sig(11, context) );
    TRACE(" x12=%016lx x13=%016lx x14=%016lx x15=%016lx\n",
          (DWORD64)REGn_sig(12, context), (DWORD64)REGn_sig(13, context),
          (DWORD64)REGn_sig(14, context), (DWORD64)REGn_sig(15, context) );
    TRACE(" x16=%016lx x17=%016lx x18=%016lx x19=%016lx\n",
          (DWORD64)REGn_sig(16, context), (DWORD64)REGn_sig(17, context),
          (DWORD64)REGn_sig(18, context), (DWORD64)REGn_sig(19, context) );
    TRACE(" x20=%016lx x21=%016lx x22=%016lx x23=%016lx\n",
          (DWORD64)REGn_sig(20, context), (DWORD64)REGn_sig(21, context),
          (DWORD64)REGn_sig(22, context), (DWORD64)REGn_sig(23, context) );
    TRACE(" x24=%016lx x25=%016lx x26=%016lx x27=%016lx\n",
          (DWORD64)REGn_sig(24, context), (DWORD64)REGn_sig(25, context),
          (DWORD64)REGn_sig(26, context), (DWORD64)REGn_sig(27, context) );
    TRACE(" x28=%016lx  fp=%016lx  lr=%016lx  sp=%016lx\n",
          (DWORD64)REGn_sig(28, context), (DWORD64)FP_sig(context),
          (DWORD64)LR_sig(context), (DWORD64)SP_sig(context) );

    if ((char *)wine_frame < (char *)frame)
    {
        TRACE( "returning to handler\n" );
        REGn_sig(0, context) = (ULONG_PTR)&wine_frame->jmp;
        REGn_sig(1, context) = 1;
        PC_sig(context)      = (ULONG_PTR)__wine_longjmp;
    }
    else
    {
        TRACE( "returning to user mode ip=%p ret=%08x\n", (void *)frame->ret_addr, rec->ExceptionCode );
        REGn_sig(0, context)  = rec->ExceptionCode;
        REGn_sig(19, context) = frame->x19;
        REGn_sig(20, context) = frame->x20;
        REGn_sig(21, context) = frame->x21;
        REGn_sig(22, context) = frame->x22;
        REGn_sig(23, context) = frame->x23;
        REGn_sig(24, context) = frame->x24;
        REGn_sig(25, context) = frame->x25;
        REGn_sig(26, context) = frame->x26;
        REGn_sig(27, context) = frame->x27;
        REGn_sig(28, context) = frame->x28;
        FP_sig(context)       = frame->x29;
        LR_sig(context)       = frame->ret_addr;
        SP_sig(context)       = (ULONG64)&frame->thunk_x29;
        PC_sig(context)       = frame->thunk_addr;
        arm64_thread_data()->syscall_frame = NULL;
    }
    return TRUE;
}


/**********************************************************************
 *		segv_handler
 *
 * Handler for SIGSEGV.
 */
static void segv_handler( int signal, siginfo_t *siginfo, void *sigcontext )
{
    EXCEPTION_RECORD rec = { 0 };
    ucontext_t *context = sigcontext;

    rec.NumberParameters = 2;
    rec.ExceptionInformation[0] = (get_fault_esr( context ) & 0x40) != 0;
    rec.ExceptionInformation[1] = (ULONG_PTR)siginfo->si_addr;
    rec.ExceptionCode = virtual_handle_fault( siginfo->si_addr, rec.ExceptionInformation[0],
                                              (void *)SP_sig(context) );
    if (!rec.ExceptionCode) return;
    if (handle_syscall_fault( context, &rec )) return;
    setup_exception( context, &rec );
}


/**********************************************************************
 *		ill_handler
 *
 * Handler for SIGILL.
 */
static void ill_handler( int signal, siginfo_t *siginfo, void *sigcontext )
{
    EXCEPTION_RECORD rec = { EXCEPTION_ILLEGAL_INSTRUCTION };

    setup_exception( sigcontext, &rec );
}


/**********************************************************************
 *		bus_handler
 *
 * Handler for SIGBUS.
 */
static void bus_handler( int signal, siginfo_t *siginfo, void *sigcontext )
{
    EXCEPTION_RECORD rec = { EXCEPTION_DATATYPE_MISALIGNMENT };

    setup_exception( sigcontext, &rec );
}


/**********************************************************************
 *		trap_handler
 *
 * Handler for SIGTRAP.
 */
static void trap_handler( int signal, siginfo_t *siginfo, void *sigcontext )
{
    EXCEPTION_RECORD rec = { 0 };

    switch (siginfo->si_code)
    {
    case TRAP_TRACE:
        rec.ExceptionCode = EXCEPTION_SINGLE_STEP;
        break;
    case TRAP_BRKPT:
    default:
        rec.ExceptionCode = EXCEPTION_BREAKPOINT;
        rec.NumberParameters = 1;
        break;
    }
    setup_exception( sigcontext, &rec );
}


/**********************************************************************
 *		fpe_handler
 *
 * Handler for SIGFPE.
 */
static void fpe_handler( int signal, siginfo_t *siginfo, void *sigcontext )
{
    EXCEPTION_RECORD rec = { 0 };

    switch (siginfo->si_code & 0xffff )
    {
#ifdef FPE_FLTSUB
    case FPE_FLTSUB:
        rec.ExceptionCode = EXCEPTION_ARRAY_BOUNDS_EXCEEDED;
        break;
#endif
#ifdef FPE_INTDIV
    case FPE_INTDIV:
        rec.ExceptionCode = EXCEPTION_INT_DIVIDE_BY_ZERO;
        break;
#endif
#ifdef FPE_INTOVF
    case FPE_INTOVF:
        rec.ExceptionCode = EXCEPTION_INT_OVERFLOW;
        break;
#endif
#ifdef FPE_FLTDIV
    case FPE_FLTDIV:
        rec.ExceptionCode = EXCEPTION_FLT_DIVIDE_BY_ZERO;
        break;
#endif
#ifdef FPE_FLTOVF
    case FPE_FLTOVF:
        rec.ExceptionCode = EXCEPTION_FLT_OVERFLOW;
        break;
#endif
#ifdef FPE_FLTUND
    case FPE_FLTUND:
        rec.ExceptionCode = EXCEPTION_FLT_UNDERFLOW;
        break;
#endif
#ifdef FPE_FLTRES
    case FPE_FLTRES:
        rec.ExceptionCode = EXCEPTION_FLT_INEXACT_RESULT;
        break;
#endif
#ifdef FPE_FLTINV
    case FPE_FLTINV:
#endif
    default:
        rec.ExceptionCode = EXCEPTION_FLT_INVALID_OPERATION;
        break;
    }
    setup_exception( sigcontext, &rec );
}


/**********************************************************************
 *		int_handler
 *
 * Handler for SIGINT.
 */
static void int_handler( int signal, siginfo_t *siginfo, void *sigcontext )
{
    EXCEPTION_RECORD rec = { CONTROL_C_EXIT };

    setup_exception( sigcontext, &rec );
}


/**********************************************************************
 *		abrt_handler
 *
 * Handler for SIGABRT.
 */
static void abrt_handler( int signal, siginfo_t *siginfo, void *sigcontext )
{
    EXCEPTION_RECORD rec = { EXCEPTION_WINE_ASSERTION, EH_NONCONTINUABLE };

    setup_exception( sigcontext, &rec );
}


/**********************************************************************
 *		quit_handler
 *
 * Handler for SIGQUIT.
 */
static void quit_handler( int signal, siginfo_t *siginfo, void *sigcontext )
{
    abort_thread(0);
}


/**********************************************************************
 *		usr1_handler
 *
 * Handler for SIGUSR1, used to signal a thread that it got suspended.
 */
static void usr1_handler( int signal, siginfo_t *siginfo, void *sigcontext )
{
    CONTEXT context;

    save_context( &context, sigcontext );
    wait_suspend( &context );
    restore_context( &context, sigcontext );
}


/**********************************************************************
 *		usr2_handler
 *
 * Handler for SIGUSR2, used to set a thread context.
 */
static void usr2_handler( int signal, siginfo_t *siginfo, void *sigcontext )
{
    CONTEXT *context = InterlockedExchangePointer( (void **)&arm64_thread_data()->context, NULL );
    if (!context) return;
    if ((context->ContextFlags & ~CONTEXT_ARM64) & CONTEXT_FLOATING_POINT)
        restore_fpu( context, sigcontext );
    restore_context( context, sigcontext );
}


/**********************************************************************
 *           get_thread_ldt_entry
 */
NTSTATUS get_thread_ldt_entry( HANDLE handle, void *data, ULONG len, ULONG *ret_len )
{
    return STATUS_NOT_IMPLEMENTED;
}


/******************************************************************************
 *           NtSetLdtEntries   (NTDLL.@)
 *           ZwSetLdtEntries   (NTDLL.@)
 */
NTSTATUS WINAPI NtSetLdtEntries( ULONG sel1, LDT_ENTRY entry1, ULONG sel2, LDT_ENTRY entry2 )
{
    return STATUS_NOT_IMPLEMENTED;
}


/**********************************************************************
 *             signal_init_threading
 */
void signal_init_threading(void)
{
    pthread_key_create( &teb_key, NULL );
}


/**********************************************************************
 *             signal_alloc_thread
 */
NTSTATUS signal_alloc_thread( TEB *teb )
{
    return STATUS_SUCCESS;
}


/**********************************************************************
 *             signal_free_thread
 */
void signal_free_thread( TEB *teb )
{
}


/**********************************************************************
 *		signal_init_thread
 */
void signal_init_thread( TEB *teb )
{
    /* Win64/ARM applications expect the TEB pointer to be in the x18 platform register. */
    __asm__ __volatile__( "mov x18, %0" : : "r" (teb) );

    pthread_setspecific( teb_key, teb );
}


/**********************************************************************
 *		signal_init_process
 */
void signal_init_process(void)
{
    struct sigaction sig_act;

    sig_act.sa_mask = server_block_set;
    sig_act.sa_flags = SA_SIGINFO | SA_RESTART | SA_ONSTACK;

    sig_act.sa_sigaction = int_handler;
    if (sigaction( SIGINT, &sig_act, NULL ) == -1) goto error;
    sig_act.sa_sigaction = fpe_handler;
    if (sigaction( SIGFPE, &sig_act, NULL ) == -1) goto error;
    sig_act.sa_sigaction = abrt_handler;
    if (sigaction( SIGABRT, &sig_act, NULL ) == -1) goto error;
    sig_act.sa_sigaction = quit_handler;
    if (sigaction( SIGQUIT, &sig_act, NULL ) == -1) goto error;
    sig_act.sa_sigaction = usr1_handler;
    if (sigaction( SIGUSR1, &sig_act, NULL ) == -1) goto error;
    sig_act.sa_sigaction = usr2_handler;
    if (sigaction( SIGUSR2, &sig_act, NULL ) == -1) goto error;
    sig_act.sa_sigaction = trap_handler;
    if (sigaction( SIGTRAP, &sig_act, NULL ) == -1) goto error;
    sig_act.sa_sigaction = segv_handler;
    if (sigaction( SIGSEGV, &sig_act, NULL ) == -1) goto error;
    sig_act.sa_sigaction = ill_handler;
    if (sigaction( SIGILL, &sig_act, NULL ) == -1) goto error;
    sig_act.sa_sigaction = bus_handler;
    if (sigaction( SIGBUS, &sig_act, NULL ) == -1) goto error;
    return;

 error:
    perror("sigaction");
    exit(1);
}


/**********************************************************************
 *		signal_init_syscalls
 */
void *signal_init_syscalls(void)
{
    return __wine_syscall_dispatcher;
}


/***********************************************************************
 *           init_thread_context
 */
static void init_thread_context( CONTEXT *context, LPTHREAD_START_ROUTINE entry, void *arg, TEB *teb )
{
    context->u.s.X0  = (DWORD64)entry;
    context->u.s.X1  = (DWORD64)arg;
    context->u.s.X18 = (DWORD64)teb;
    context->Sp      = (DWORD64)teb->Tib.StackBase;
    context->Pc      = (DWORD64)pRtlUserThreadStart;
}


/***********************************************************************
 *           get_initial_context
 */
PCONTEXT DECLSPEC_HIDDEN get_initial_context( LPTHREAD_START_ROUTINE entry, void *arg,
                                              BOOL suspend, TEB *teb )
{
    CONTEXT *ctx;

    if (suspend)
    {
        CONTEXT context = { CONTEXT_ALL };

        init_thread_context( &context, entry, arg, teb );
        wait_suspend( &context );
        ctx = (CONTEXT *)((ULONG_PTR)context.Sp & ~15) - 1;
        *ctx = context;
    }
    else
    {
        ctx = (CONTEXT *)teb->Tib.StackBase - 1;
        init_thread_context( ctx, entry, arg, teb );
    }
    pthread_sigmask( SIG_UNBLOCK, &server_block_set, NULL );
    ctx->ContextFlags = CONTEXT_FULL;
    return ctx;
}


/***********************************************************************
 *           signal_start_thread
 */
__ASM_GLOBAL_FUNC( signal_start_thread,
                   "stp x29, x30, [sp,#-16]!\n\t"
                   "mov x19, x3\n\t"             /* thunk */
                   "mov x18, x4\n\t"             /* teb */
                   /* store exit frame */
                   "mov x29, sp\n\t"
                   "str x29, [x4, #0x2f0]\n\t"  /* arm64_thread_data()->exit_frame */
                   /* switch to thread stack */
                   "ldr x5, [x4, #8]\n\t"       /* teb->Tib.StackBase */
                   "sub sp, x5, #0x1000\n\t"
                   /* attach dlls */
                   "mov x3, x4\n\t"
                   "bl " __ASM_NAME("get_initial_context") "\n\t"
                   "mov lr, #0\n\t"
                   "br x19" )


extern void DECLSPEC_NORETURN call_thread_exit_func( int status, void (*func)(int), TEB *teb );
__ASM_GLOBAL_FUNC( call_thread_exit_func,
                   "stp x29, x30, [sp,#-16]!\n\t"
                   "ldr x3, [x2, #0x2f0]\n\t"  /* arm64_thread_data()->exit_frame */
                   "str xzr, [x2, #0x2f0]\n\t"
                   "cbz x3, 1f\n\t"
                   "mov sp, x3\n"
                   "1:\tldp x29, x30, [sp], #16\n\t"
                   "br x1" )

/***********************************************************************
 *           signal_exit_thread
 */
void signal_exit_thread( int status, void (*func)(int) )
{
    call_thread_exit_func( status, func, NtCurrentTeb() );
}


/**********************************************************************
 *           NtCurrentTeb   (NTDLL.@)
 */
TEB * WINAPI NtCurrentTeb(void)
{
    return pthread_getspecific( teb_key );
}

#endif  /* __aarch64__ */