Home | History | Annotate | Line # | Download | only in amd64
linux_machdep.c revision 1.20.2.1
      1 /*	$NetBSD: linux_machdep.c,v 1.20.2.1 2007/04/10 13:26:21 ad Exp $ */
      2 
      3 /*-
      4  * Copyright (c) 2005 Emmanuel Dreyfus, all rights reserved.
      5  *
      6  * Redistribution and use in source and binary forms, with or without
      7  * modification, are permitted provided that the following conditions
      8  * are met:
      9  * 1. Redistributions of source code must retain the above copyright
     10  *    notice, this list of conditions and the following disclaimer.
     11  * 2. Redistributions in binary form must reproduce the above copyright
     12  *    notice, this list of conditions and the following disclaimer in the
     13  *    documentation and/or other materials provided with the distribution.
     14  * 3. All advertising materials mentioning features or use of this software
     15  *    must display the following acknowledgement:
     16  *	This product includes software developed by Emmanuel Dreyfus
     17  * 4. The name of the author may not be used to endorse or promote
     18  *    products derived from this software without specific prior written
     19  *    permission.
     20  *
     21  * THIS SOFTWARE IS PROVIDED BY THE THE AUTHOR AND CONTRIBUTORS ``AS IS''
     22  * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
     23  * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
     24  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS
     25  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
     26  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
     27  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
     28  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
     29  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
     30  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
     31  * POSSIBILITY OF SUCH DAMAGE.
     32  */
     33 
     34 #include <sys/cdefs.h>
     35 
     36 __KERNEL_RCSID(0, "$NetBSD: linux_machdep.c,v 1.20.2.1 2007/04/10 13:26:21 ad Exp $");
     37 
     38 #include <sys/param.h>
     39 #include <sys/types.h>
     40 #include <sys/systm.h>
     41 #include <sys/signal.h>
     42 #include <sys/exec.h>
     43 #include <sys/proc.h>
     44 #include <sys/ptrace.h> /* for process_read_fpregs() */
     45 #include <sys/user.h>
     46 #include <sys/wait.h>
     47 #include <sys/ucontext.h>
     48 #include <sys/conf.h>
     49 
     50 #include <machine/reg.h>
     51 #include <machine/pcb.h>
     52 #include <machine/fpu.h>
     53 #include <machine/mcontext.h>
     54 #include <machine/specialreg.h>
     55 #include <machine/vmparam.h>
     56 
     57 /*
     58  * To see whether wscons is configured (for virtual console ioctl calls).
     59  */
     60 #if defined(_KERNEL_OPT)
     61 #include "wsdisplay.h"
     62 #endif
     63 #if (NWSDISPLAY > 0)
     64 #include <dev/wscons/wsconsio.h>
     65 #include <dev/wscons/wsdisplay_usl_io.h>
     66 #endif
     67 
     68 
     69 #include <compat/linux/common/linux_signal.h>
     70 #include <compat/linux/common/linux_errno.h>
     71 #include <compat/linux/common/linux_exec.h>
     72 #include <compat/linux/common/linux_ioctl.h>
     73 #include <compat/linux/common/linux_prctl.h>
     74 #include <compat/linux/common/linux_machdep.h>
     75 #include <compat/linux/linux_syscall.h>
     76 #include <compat/linux/linux_syscallargs.h>
     77 
     78 static void linux_buildcontext(struct lwp *, void *, void *);
     79 
     80 void
     81 linux_setregs(l, epp, stack)
     82         struct lwp *l;
     83 	struct exec_package *epp;
     84 	u_long stack;
     85 {
     86 	struct pcb *pcb = &l->l_addr->u_pcb;
     87 	struct trapframe *tf;
     88 
     89 	/* If we were using the FPU, forget about it. */
     90 	if (l->l_addr->u_pcb.pcb_fpcpu != NULL)
     91 		fpusave_lwp(l, 0);
     92 
     93 	l->l_md.md_flags &= ~MDP_USEDFPU;
     94 	pcb->pcb_flags = 0;
     95 	pcb->pcb_savefpu.fp_fxsave.fx_fcw = __NetBSD_NPXCW__;
     96 	pcb->pcb_savefpu.fp_fxsave.fx_mxcsr = __INITIAL_MXCSR__;
     97 	pcb->pcb_savefpu.fp_fxsave.fx_mxcsr_mask = __INITIAL_MXCSR_MASK__;
     98 	pcb->pcb_fs = 0;
     99 	pcb->pcb_gs = 0;
    100 
    101 	l->l_proc->p_flag &= ~PK_32;
    102 
    103 	tf = l->l_md.md_regs;
    104 	tf->tf_rax = 0;
    105 	tf->tf_rbx = 0;
    106 	tf->tf_rcx = epp->ep_entry;
    107 	tf->tf_rdx = 0;
    108 	tf->tf_rsi = 0;
    109 	tf->tf_rdi = 0;
    110 	tf->tf_rbp = 0;
    111 	tf->tf_rsp = stack;
    112 	tf->tf_r8 = 0;
    113 	tf->tf_r9 = 0;
    114 	tf->tf_r10 = 0;
    115 	tf->tf_r11 = 0;
    116 	tf->tf_r12 = 0;
    117 	tf->tf_r13 = 0;
    118 	tf->tf_r14 = 0;
    119 	tf->tf_r15 = 0;
    120 	tf->tf_rip = epp->ep_entry;
    121 	tf->tf_rflags = PSL_USERSET;
    122 	tf->tf_cs = GSEL(GUCODE_SEL, SEL_UPL);
    123 	tf->tf_ss = GSEL(GUDATA_SEL, SEL_UPL);
    124 	tf->tf_ds = 0;
    125 	tf->tf_es = 0;
    126 	tf->tf_fs = 0;
    127 	tf->tf_gs = 0;
    128 
    129 	return;
    130 }
    131 
    132 void
    133 linux_sendsig(ksi, mask)
    134 	const ksiginfo_t *ksi;
    135 	const sigset_t *mask;
    136 {
    137 	struct lwp *l = curlwp;
    138 	struct proc *p = l->l_proc;
    139 	struct sigacts *ps = p->p_sigacts;
    140 	int onstack, error;
    141 	int sig = ksi->ksi_signo;
    142 	struct linux_rt_sigframe *sfp, sigframe;
    143 	struct linux__fpstate *fpsp, fpstate;
    144 	struct fpreg fpregs;
    145 	struct trapframe *tf = l->l_md.md_regs;
    146 	sig_t catcher = SIGACTION(p, sig).sa_handler;
    147 	linux_sigset_t lmask;
    148 	char *sp;
    149 
    150 	/* Do we need to jump onto the signal stack? */
    151 	onstack =
    152 	    (l->l_sigstk.ss_flags & (SS_DISABLE | SS_ONSTACK)) == 0 &&
    153 	    (SIGACTION(p, sig).sa_flags & SA_ONSTACK) != 0;
    154 
    155 	/* Allocate space for the signal handler context. */
    156 	if (onstack)
    157 		sp = ((char *)l->l_sigstk.ss_sp +
    158 		    l->l_sigstk.ss_size);
    159 	else
    160 		sp = (char *)tf->tf_rsp - 128;
    161 
    162 	/*
    163 	 * Save FPU state, if any
    164 	 */
    165 	if (l->l_md.md_flags & MDP_USEDFPU) {
    166 		sp = (char *)
    167 		    (((long)sp - sizeof(struct linux__fpstate)) & ~0xfUL);
    168 		fpsp = (struct linux__fpstate *)sp;
    169 	} else
    170 		fpsp = NULL;
    171 
    172 	/*
    173 	 * Populate the rt_sigframe
    174 	 */
    175 	sp = (char *)
    176 	    ((((long)sp - sizeof(struct linux_rt_sigframe)) & ~0xfUL) - 8);
    177 	sfp = (struct linux_rt_sigframe *)sp;
    178 
    179 	bzero(&sigframe, sizeof(sigframe));
    180 	if (ps->sa_sigdesc[sig].sd_vers != 0)
    181 		sigframe.pretcode =
    182 		    (char *)(u_long)ps->sa_sigdesc[sig].sd_tramp;
    183 	else
    184 		sigframe.pretcode = NULL;
    185 
    186 	/*
    187 	 * The user context
    188 	 */
    189 	sigframe.uc.luc_flags = 0;
    190 	sigframe.uc.luc_link = NULL;
    191 
    192 	/* This is used regardless of SA_ONSTACK in Linux */
    193 	sigframe.uc.luc_stack.ss_sp = l->l_sigstk.ss_sp;
    194 	sigframe.uc.luc_stack.ss_size = l->l_sigstk.ss_size;
    195 	sigframe.uc.luc_stack.ss_flags = 0;
    196 	if (l->l_sigstk.ss_flags & SS_ONSTACK)
    197 		sigframe.uc.luc_stack.ss_flags |= LINUX_SS_ONSTACK;
    198 	if (l->l_sigstk.ss_flags & SS_DISABLE)
    199 		sigframe.uc.luc_stack.ss_flags |= LINUX_SS_DISABLE;
    200 
    201 	sigframe.uc.luc_mcontext.r8 = tf->tf_r8;
    202 	sigframe.uc.luc_mcontext.r9 = tf->tf_r9;
    203 	sigframe.uc.luc_mcontext.r10 = tf->tf_r10;
    204 	sigframe.uc.luc_mcontext.r11 = tf->tf_r11;
    205 	sigframe.uc.luc_mcontext.r12 = tf->tf_r12;
    206 	sigframe.uc.luc_mcontext.r13 = tf->tf_r13;
    207 	sigframe.uc.luc_mcontext.r14 = tf->tf_r14;
    208 	sigframe.uc.luc_mcontext.r15 = tf->tf_r15;
    209 	sigframe.uc.luc_mcontext.rdi = tf->tf_rdi;
    210 	sigframe.uc.luc_mcontext.rsi = tf->tf_rsi;
    211 	sigframe.uc.luc_mcontext.rbp = tf->tf_rbp;
    212 	sigframe.uc.luc_mcontext.rbx = tf->tf_rbx;
    213 	sigframe.uc.luc_mcontext.rdx = tf->tf_rdx;
    214 	sigframe.uc.luc_mcontext.rcx = tf->tf_rcx;
    215 	sigframe.uc.luc_mcontext.rsp = tf->tf_rsp;
    216 	sigframe.uc.luc_mcontext.rip = tf->tf_rip;
    217 	sigframe.uc.luc_mcontext.eflags = tf->tf_rflags;
    218 	sigframe.uc.luc_mcontext.cs = tf->tf_cs;
    219 	sigframe.uc.luc_mcontext.gs = tf->tf_gs;
    220 	sigframe.uc.luc_mcontext.fs = tf->tf_fs;
    221 	sigframe.uc.luc_mcontext.err = tf->tf_err;
    222 	sigframe.uc.luc_mcontext.trapno = tf->tf_trapno;
    223 	native_to_linux_sigset(&lmask, mask);
    224 	sigframe.uc.luc_mcontext.oldmask = lmask.sig[0];
    225 	sigframe.uc.luc_mcontext.cr2 = (long)l->l_addr->u_pcb.pcb_onfault;
    226 	sigframe.uc.luc_mcontext.fpstate = fpsp;
    227 	native_to_linux_sigset(&sigframe.uc.luc_sigmask, mask);
    228 
    229 	/*
    230 	 * the siginfo structure
    231 	 */
    232 	sigframe.info.lsi_signo = native_to_linux_signo[sig];
    233 	sigframe.info.lsi_errno = native_to_linux_errno[ksi->ksi_errno];
    234 	sigframe.info.lsi_code = ksi->ksi_code;
    235 
    236 	/* XXX This is a rought conversion, taken from i386 code */
    237 	switch (sigframe.info.lsi_signo) {
    238 	case LINUX_SIGILL:
    239 	case LINUX_SIGFPE:
    240 	case LINUX_SIGSEGV:
    241 	case LINUX_SIGBUS:
    242 	case LINUX_SIGTRAP:
    243 		sigframe.info._sifields._sigfault._addr = ksi->ksi_addr;
    244 		break;
    245 	case LINUX_SIGCHLD:
    246 		sigframe.info._sifields._sigchld._pid = ksi->ksi_pid;
    247 		sigframe.info._sifields._sigchld._uid = ksi->ksi_uid;
    248 		sigframe.info._sifields._sigchld._utime = ksi->ksi_utime;
    249 		sigframe.info._sifields._sigchld._stime = ksi->ksi_stime;
    250 
    251 		if (WCOREDUMP(ksi->ksi_status)) {
    252 			sigframe.info.lsi_code = LINUX_CLD_DUMPED;
    253 			sigframe.info._sifields._sigchld._status =
    254 			    _WSTATUS(ksi->ksi_status);
    255 		} else if (_WSTATUS(ksi->ksi_status)) {
    256 			sigframe.info.lsi_code = LINUX_CLD_KILLED;
    257 			sigframe.info._sifields._sigchld._status =
    258 			    _WSTATUS(ksi->ksi_status);
    259 		} else {
    260 			sigframe.info.lsi_code = LINUX_CLD_EXITED;
    261 			sigframe.info._sifields._sigchld._status =
    262 			    ((ksi->ksi_status & 0xff00U) >> 8);
    263 		}
    264 		break;
    265 	case LINUX_SIGIO:
    266 		sigframe.info._sifields._sigpoll._band = ksi->ksi_band;
    267 		sigframe.info._sifields._sigpoll._fd = ksi->ksi_fd;
    268 		break;
    269 	default:
    270 		sigframe.info._sifields._sigchld._pid = ksi->ksi_pid;
    271 		sigframe.info._sifields._sigchld._uid = ksi->ksi_uid;
    272 		if ((sigframe.info.lsi_signo == LINUX_SIGALRM) ||
    273 		    (sigframe.info.lsi_signo >= LINUX_SIGRTMIN))
    274 			sigframe.info._sifields._timer._sigval.sival_ptr =
    275 			     ksi->ksi_sigval.sival_ptr;
    276 		break;
    277 	}
    278 
    279 	sendsig_reset(l, sig);
    280 	mutex_exit(&p->p_smutex);
    281 	error = 0;
    282 
    283 	/*
    284 	 * Save FPU state, if any
    285 	 */
    286 	if (fpsp != NULL) {
    287 		(void)process_read_fpregs(l, &fpregs);
    288 		bzero(&fpstate, sizeof(fpstate));
    289 		fpstate.cwd = fpregs.fp_fcw;
    290 		fpstate.swd = fpregs.fp_fsw;
    291 		fpstate.twd = fpregs.fp_ftw;
    292 		fpstate.fop = fpregs.fp_fop;
    293 		fpstate.rip = fpregs.fp_rip;
    294 		fpstate.rdp = fpregs.fp_rdp;
    295 		fpstate.mxcsr = fpregs.fp_mxcsr;
    296 		fpstate.mxcsr_mask = fpregs.fp_mxcsr_mask;
    297 		memcpy(&fpstate.st_space, &fpregs.fp_st,
    298 		    sizeof(fpstate.st_space));
    299 		memcpy(&fpstate.xmm_space, &fpregs.fp_xmm,
    300 		    sizeof(fpstate.xmm_space));
    301 		error = copyout(&fpstate, fpsp, sizeof(fpstate));
    302 	}
    303 
    304 	if (error == 0)
    305 		error = copyout(&sigframe, sp, sizeof(sigframe));
    306 
    307 	mutex_enter(&p->p_smutex);
    308 
    309 	if (error != 0) {
    310 		sigexit(l, SIGILL);
    311 		return;
    312 	}
    313 
    314 	linux_buildcontext(l, catcher, sp);
    315 	tf->tf_rdi = sigframe.info.lsi_signo;
    316 	tf->tf_rax = 0;
    317 	tf->tf_rsi = (long)&sfp->info;
    318 	tf->tf_rdx = (long)&sfp->uc;
    319 
    320 	/*
    321 	 * Remember we use signal stack
    322 	 */
    323 	if (onstack)
    324 		l->l_sigstk.ss_flags |= SS_ONSTACK;
    325 	return;
    326 }
    327 
    328 int
    329 linux_sys_modify_ldt(l, v, retval)
    330         struct lwp *l;
    331         void *v;
    332         register_t *retval;
    333 {
    334 	printf("linux_sys_modify_ldt\n");
    335 	return 0;
    336 }
    337 
    338 int
    339 linux_sys_iopl(l, v, retval)
    340         struct lwp *l;
    341         void *v;
    342         register_t *retval;
    343 {
    344 	return 0;
    345 }
    346 
    347 int
    348 linux_sys_ioperm(l, v, retval)
    349         struct lwp *l;
    350         void *v;
    351         register_t *retval;
    352 {
    353 	return 0;
    354 }
    355 
    356 dev_t
    357 linux_fakedev(dev, raw)
    358         dev_t dev;
    359 	int raw;
    360 {
    361 
    362        extern const struct cdevsw ptc_cdevsw, pts_cdevsw;
    363        const struct cdevsw *cd = cdevsw_lookup(dev);
    364 
    365        if (raw) {
    366 #if (NWSDISPLAY > 0)
    367 	       extern const struct cdevsw wsdisplay_cdevsw;
    368 	       if (cd == &wsdisplay_cdevsw)
    369 		       return makedev(LINUX_CONS_MAJOR, (minor(dev) + 1));
    370 #endif
    371        }
    372 
    373        if (cd == &ptc_cdevsw)
    374 	       return makedev(LINUX_PTC_MAJOR, minor(dev));
    375        if (cd == &pts_cdevsw)
    376 	       return makedev(LINUX_PTS_MAJOR, minor(dev));
    377 
    378 	return ((minor(dev) & 0xff) | ((major(dev) & 0xfff) << 8)
    379 	    | (((unsigned long long int) (minor(dev) & ~0xff)) << 12)
    380 	    | (((unsigned long long int) (major(dev) & ~0xfff)) << 32));
    381 }
    382 
    383 int
    384 linux_machdepioctl(l, v, retval)
    385         struct lwp *l;
    386         void *v;
    387         register_t *retval;
    388 {
    389 	return 0;
    390 }
    391 
    392 int
    393 linux_sys_rt_sigreturn(l, v, retval)
    394         struct lwp *l;
    395         void *v;
    396         register_t *retval;
    397 {
    398 	struct linux_ucontext *luctx;
    399 	struct trapframe *tf = l->l_md.md_regs;
    400 	struct linux_sigcontext *lsigctx;
    401 	struct linux__fpstate fpstate;
    402 	struct linux_rt_sigframe frame, *fp;
    403 	ucontext_t uctx;
    404 	mcontext_t *mctx;
    405 	struct fxsave64 *fxsave;
    406 	int error;
    407 
    408 	fp = (struct linux_rt_sigframe *)(tf->tf_rsp - 8);
    409 	if ((error = copyin(fp, &frame, sizeof(frame))) != 0) {
    410 		mutex_enter(&l->l_proc->p_smutex);
    411 		sigexit(l, SIGILL);
    412 		return error;
    413 	}
    414 	luctx = &frame.uc;
    415 	lsigctx = &luctx->luc_mcontext;
    416 
    417 	bzero(&uctx, sizeof(uctx));
    418 	mctx = (mcontext_t *)&uctx.uc_mcontext;
    419 	fxsave = (struct fxsave64 *)&mctx->__fpregs;
    420 
    421 	/*
    422 	 * Set the flags. Linux always have CPU, stack and signal state,
    423 	 * FPU is optional. uc_flags is not used to tell what we have.
    424 	 */
    425 	uctx.uc_flags = (_UC_SIGMASK|_UC_CPU|_UC_STACK|_UC_CLRSTACK);
    426 	if (lsigctx->fpstate != NULL)
    427 		uctx.uc_flags |= _UC_FPU;
    428 	uctx.uc_link = NULL;
    429 
    430 	/*
    431 	 * Signal set
    432 	 */
    433 	linux_to_native_sigset(&uctx.uc_sigmask, &luctx->luc_sigmask);
    434 
    435 	/*
    436 	 * CPU state
    437 	 */
    438 	mctx->__gregs[_REG_R8] = lsigctx->r8;
    439 	mctx->__gregs[_REG_R9] = lsigctx->r9;
    440 	mctx->__gregs[_REG_R10] = lsigctx->r10;
    441 	mctx->__gregs[_REG_R11] = lsigctx->r11;
    442 	mctx->__gregs[_REG_R12] = lsigctx->r12;
    443 	mctx->__gregs[_REG_R13] = lsigctx->r13;
    444 	mctx->__gregs[_REG_R14] = lsigctx->r14;
    445 	mctx->__gregs[_REG_R15] = lsigctx->r15;
    446 	mctx->__gregs[_REG_RDI] = lsigctx->rdi;
    447 	mctx->__gregs[_REG_RSI] = lsigctx->rsi;
    448 	mctx->__gregs[_REG_RBP] = lsigctx->rbp;
    449 	mctx->__gregs[_REG_RBX] = lsigctx->rbx;
    450 	mctx->__gregs[_REG_RAX] = tf->tf_rax;
    451 	mctx->__gregs[_REG_RDX] = lsigctx->rdx;
    452 	mctx->__gregs[_REG_RCX] = lsigctx->rcx;
    453 	mctx->__gregs[_REG_RIP] = lsigctx->rip;
    454 	mctx->__gregs[_REG_RFL] = lsigctx->eflags;
    455 	mctx->__gregs[_REG_CS] = lsigctx->cs;
    456 	mctx->__gregs[_REG_GS] = lsigctx->gs;
    457 	mctx->__gregs[_REG_FS] = lsigctx->fs;
    458 	mctx->__gregs[_REG_ERR] = lsigctx->err;
    459 	mctx->__gregs[_REG_TRAPNO] = lsigctx->trapno;
    460 	mctx->__gregs[_REG_ES] = tf->tf_es;
    461 	mctx->__gregs[_REG_DS] = tf->tf_ds;
    462 	mctx->__gregs[_REG_URSP] = lsigctx->rsp; /* XXX */
    463 	mctx->__gregs[_REG_SS] = tf->tf_ss;
    464 
    465 	/*
    466 	 * FPU state
    467 	 */
    468 	if (lsigctx->fpstate != NULL) {
    469 		error = copyin(lsigctx->fpstate, &fpstate, sizeof(fpstate));
    470 		if (error != 0) {
    471 			mutex_enter(&l->l_proc->p_smutex);
    472 			sigexit(l, SIGILL);
    473 			return error;
    474 		}
    475 
    476 		fxsave->fx_fcw = fpstate.cwd;
    477 		fxsave->fx_fsw = fpstate.swd;
    478 		fxsave->fx_ftw = fpstate.twd;
    479 		fxsave->fx_fop = fpstate.fop;
    480 		fxsave->fx_rip = fpstate.rip;
    481 		fxsave->fx_rdp = fpstate.rdp;
    482 		fxsave->fx_mxcsr = fpstate.mxcsr;
    483 		fxsave->fx_mxcsr_mask = fpstate.mxcsr_mask;
    484 		memcpy(&fxsave->fx_st, &fpstate.st_space,
    485 		    sizeof(fxsave->fx_st));
    486 		memcpy(&fxsave->fx_xmm, &fpstate.xmm_space,
    487 		    sizeof(fxsave->fx_xmm));
    488 	}
    489 
    490 	/*
    491 	 * And the stack
    492 	 */
    493 	uctx.uc_stack.ss_flags = 0;
    494 	if (luctx->luc_stack.ss_flags & LINUX_SS_ONSTACK);
    495 		uctx.uc_stack.ss_flags = SS_ONSTACK;
    496 
    497 	if (luctx->luc_stack.ss_flags & LINUX_SS_DISABLE);
    498 		uctx.uc_stack.ss_flags = SS_DISABLE;
    499 
    500 	uctx.uc_stack.ss_sp = luctx->luc_stack.ss_sp;
    501 	uctx.uc_stack.ss_size = luctx->luc_stack.ss_size;
    502 
    503 	/*
    504 	 * And let setucontext deal with that.
    505 	 */
    506 	mutex_enter(&l->l_proc->p_smutex);
    507 	error = setucontext(l, &uctx);
    508 	mutex_exit(&l->l_proc->p_smutex);
    509 
    510 	return error;
    511 }
    512 
    513 int
    514 linux_sys_arch_prctl(l, v, retval)
    515 	struct lwp *l;
    516 	void *v;
    517 	register_t *retval;
    518 {
    519 	struct linux_sys_arch_prctl_args /* {
    520 		syscallarg(int) code;
    521 		syscallarg(unsigned long) addr;
    522 	} */ *uap = v;
    523 	struct pcb *pcb = &l->l_addr->u_pcb;
    524 	struct trapframe *tf = l->l_md.md_regs;
    525 	int error;
    526 	uint64_t taddr;
    527 
    528 	switch(SCARG(uap, code)) {
    529 	case LINUX_ARCH_SET_GS:
    530 		taddr = SCARG(uap, addr);
    531 		if (taddr >= VM_MAXUSER_ADDRESS)
    532 			return EINVAL;
    533 		pcb->pcb_gs = taddr;
    534 		pcb->pcb_flags |= PCB_GS64;
    535 		if (l == curlwp)
    536 			wrmsr(MSR_KERNELGSBASE, taddr);
    537 		break;
    538 
    539 	case LINUX_ARCH_GET_GS:
    540 		if (pcb->pcb_flags & PCB_GS64)
    541 			taddr = pcb->pcb_gs;
    542 		else {
    543 			error = memseg_baseaddr(l, tf->tf_fs, NULL, 0, &taddr);
    544 			if (error != 0)
    545 				return error;
    546 		}
    547 		error = copyout(&taddr, (char *)SCARG(uap, addr), 8);
    548 		if (error != 0)
    549 			return error;
    550 		break;
    551 
    552 	case LINUX_ARCH_SET_FS:
    553 		taddr = SCARG(uap, addr);
    554 		if (taddr >= VM_MAXUSER_ADDRESS)
    555 			return EINVAL;
    556 		pcb->pcb_fs = taddr;
    557 		pcb->pcb_flags |= PCB_FS64;
    558 		if (l == curlwp)
    559 			wrmsr(MSR_FSBASE, taddr);
    560 		break;
    561 
    562 	case LINUX_ARCH_GET_FS:
    563 		if (pcb->pcb_flags & PCB_FS64)
    564 			taddr = pcb->pcb_fs;
    565 		else {
    566 			error = memseg_baseaddr(l, tf->tf_fs, NULL, 0, &taddr);
    567 			if (error != 0)
    568 				return error;
    569 		}
    570 		error = copyout(&taddr, (char *)SCARG(uap, addr), 8);
    571 		if (error != 0)
    572 			return error;
    573 		break;
    574 
    575 	default:
    576 #ifdef DEBUG_LINUX
    577 		printf("linux_sys_arch_prctl: unexpected code %d\n",
    578 		    SCARG(uap, code));
    579 #endif
    580 		return EINVAL;
    581 	}
    582 
    583 	return 0;
    584 }
    585 
    586 const int linux_vsyscall_to_syscall[] = {
    587 	LINUX_SYS_gettimeofday,
    588 	LINUX_SYS_time,
    589 	LINUX_SYS_nosys,
    590 	LINUX_SYS_nosys,
    591 };
    592 
    593 int
    594 linux_usertrap(struct lwp *l, vaddr_t trapaddr, void *arg)
    595 {
    596 	struct trapframe *tf = arg;
    597 	uint64_t retaddr;
    598 	int vsyscallnr;
    599 
    600 	/*
    601 	 * Check for a vsyscall. %rip must be the fault address,
    602 	 * and the address must be in the Linux vsyscall area.
    603 	 * Also, vsyscalls are only done at 1024-byte boundaries.
    604 	 */
    605 
    606 	if (__predict_true(trapaddr < LINUX_VSYSCALL_START))
    607 		return 0;
    608 
    609 	if (trapaddr != tf->tf_rip)
    610 		return 0;
    611 
    612 	if ((tf->tf_rip & (LINUX_VSYSCALL_SIZE - 1)) != 0)
    613 		return 0;
    614 
    615 	vsyscallnr = (tf->tf_rip - LINUX_VSYSCALL_START) / LINUX_VSYSCALL_SIZE;
    616 
    617 	if (vsyscallnr > LINUX_VSYSCALL_MAXNR)
    618 		return 0;
    619 
    620 	/*
    621 	 * Get the return address from the top of the stack,
    622 	 * and fix up the return address.
    623 	 * This assumes the faulting instruction was callq *reg,
    624 	 * which is the only way that vsyscalls are ever entered.
    625 	 */
    626 	if (copyin((void *)tf->tf_rsp, &retaddr, sizeof retaddr) != 0)
    627 		return 0;
    628 	tf->tf_rip = retaddr;
    629 	tf->tf_rax = linux_vsyscall_to_syscall[vsyscallnr];
    630 	tf->tf_rsp += 8;	/* "pop" the return address */
    631 
    632 #if 0
    633 	printf("usertrap: rip %p rsp %p retaddr %p vsys %d sys %d\n",
    634 	    (void *)tf->tf_rip, (void *)tf->tf_rsp, (void *)retaddr,
    635 	    vsyscallnr, (int)tf->tf_rax);
    636 #endif
    637 
    638 	(*l->l_proc->p_md.md_syscall)(tf);
    639 
    640 	return 1;
    641 }
    642 
    643 static void
    644 linux_buildcontext(struct lwp *l, void *catcher, void *f)
    645 {
    646 	struct trapframe *tf = l->l_md.md_regs;
    647 
    648 	tf->tf_ds = GSEL(GUDATA_SEL, SEL_UPL);
    649 	tf->tf_rip = (u_int64_t)catcher;
    650 	tf->tf_cs = GSEL(GUCODE_SEL, SEL_UPL);
    651 	tf->tf_rflags &= ~(PSL_T|PSL_VM|PSL_AC);
    652 	tf->tf_rsp = (u_int64_t)f;
    653 	tf->tf_ss = GSEL(GUDATA_SEL, SEL_UPL);
    654 }
    655 
    656 void *
    657 linux_get_newtls(l)
    658 	struct lwp *l;
    659 {
    660 	struct trapframe *tf = l->l_md.md_regs;
    661 
    662 	return (void *)tf->tf_r8;
    663 }
    664 
    665 int
    666 linux_set_newtls(l, tls)
    667 	struct lwp *l;
    668 	void *tls;
    669 {
    670 	struct linux_sys_arch_prctl_args cup;
    671 	register_t retval;
    672 
    673 	SCARG(&cup, code) = LINUX_ARCH_SET_FS;
    674 	SCARG(&cup, addr) = (unsigned long)tls;
    675 
    676 	return linux_sys_arch_prctl(l, &cup, &retval);
    677 }
    678