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linux_machdep.c revision 1.18
      1 /*	$NetBSD: linux_machdep.c,v 1.18 2007/02/17 22:31:41 pavel 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 1.18 2007/02/17 22:31:41 pavel 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 
     49 #include <machine/reg.h>
     50 #include <machine/pcb.h>
     51 #include <machine/fpu.h>
     52 #include <machine/mcontext.h>
     53 #include <machine/specialreg.h>
     54 #include <machine/vmparam.h>
     55 
     56 #include <compat/linux/common/linux_signal.h>
     57 #include <compat/linux/common/linux_errno.h>
     58 #include <compat/linux/common/linux_exec.h>
     59 #include <compat/linux/common/linux_ioctl.h>
     60 #include <compat/linux/common/linux_prctl.h>
     61 #include <compat/linux/common/linux_machdep.h>
     62 #include <compat/linux/linux_syscall.h>
     63 #include <compat/linux/linux_syscallargs.h>
     64 
     65 static void linux_buildcontext(struct lwp *, void *, void *);
     66 
     67 void
     68 linux_setregs(l, epp, stack)
     69         struct lwp *l;
     70 	struct exec_package *epp;
     71 	u_long stack;
     72 {
     73 	struct pcb *pcb = &l->l_addr->u_pcb;
     74 	struct trapframe *tf;
     75 
     76 	/* If we were using the FPU, forget about it. */
     77 	if (l->l_addr->u_pcb.pcb_fpcpu != NULL)
     78 		fpusave_lwp(l, 0);
     79 
     80 	l->l_md.md_flags &= ~MDP_USEDFPU;
     81 	pcb->pcb_flags = 0;
     82 	pcb->pcb_savefpu.fp_fxsave.fx_fcw = __NetBSD_NPXCW__;
     83 	pcb->pcb_savefpu.fp_fxsave.fx_mxcsr = __INITIAL_MXCSR__;
     84 	pcb->pcb_savefpu.fp_fxsave.fx_mxcsr_mask = __INITIAL_MXCSR_MASK__;
     85 	pcb->pcb_fs = 0;
     86 	pcb->pcb_gs = 0;
     87 
     88 	l->l_proc->p_flag &= ~PK_32;
     89 
     90 	tf = l->l_md.md_regs;
     91 	tf->tf_rax = 0;
     92 	tf->tf_rbx = 0;
     93 	tf->tf_rcx = epp->ep_entry;
     94 	tf->tf_rdx = 0;
     95 	tf->tf_rsi = 0;
     96 	tf->tf_rdi = 0;
     97 	tf->tf_rbp = 0;
     98 	tf->tf_rsp = stack;
     99 	tf->tf_r8 = 0;
    100 	tf->tf_r9 = 0;
    101 	tf->tf_r10 = 0;
    102 	tf->tf_r11 = 0;
    103 	tf->tf_r12 = 0;
    104 	tf->tf_r13 = 0;
    105 	tf->tf_r14 = 0;
    106 	tf->tf_r15 = 0;
    107 	tf->tf_rip = epp->ep_entry;
    108 	tf->tf_rflags = PSL_USERSET;
    109 	tf->tf_cs = GSEL(GUCODE_SEL, SEL_UPL);
    110 	tf->tf_ss = GSEL(GUDATA_SEL, SEL_UPL);
    111 	tf->tf_ds = 0;
    112 	tf->tf_es = 0;
    113 	tf->tf_fs = 0;
    114 	tf->tf_gs = 0;
    115 
    116 	return;
    117 }
    118 
    119 void
    120 linux_sendsig(ksi, mask)
    121 	const ksiginfo_t *ksi;
    122 	const sigset_t *mask;
    123 {
    124 	struct lwp *l = curlwp;
    125 	struct proc *p = l->l_proc;
    126 	struct sigacts *ps = p->p_sigacts;
    127 	int onstack, error;
    128 	int sig = ksi->ksi_signo;
    129 	struct linux_rt_sigframe *sfp, sigframe;
    130 	struct linux__fpstate *fpsp, fpstate;
    131 	struct fpreg fpregs;
    132 	struct trapframe *tf = l->l_md.md_regs;
    133 	sig_t catcher = SIGACTION(p, sig).sa_handler;
    134 	linux_sigset_t lmask;
    135 	char *sp;
    136 
    137 	/* Do we need to jump onto the signal stack? */
    138 	onstack =
    139 	    (l->l_sigstk.ss_flags & (SS_DISABLE | SS_ONSTACK)) == 0 &&
    140 	    (SIGACTION(p, sig).sa_flags & SA_ONSTACK) != 0;
    141 
    142 	/* Allocate space for the signal handler context. */
    143 	if (onstack)
    144 		sp = ((caddr_t)l->l_sigstk.ss_sp +
    145 		    l->l_sigstk.ss_size);
    146 	else
    147 		sp = (caddr_t)tf->tf_rsp - 128;
    148 
    149 	/*
    150 	 * Save FPU state, if any
    151 	 */
    152 	if (l->l_md.md_flags & MDP_USEDFPU) {
    153 		sp = (char *)
    154 		    (((long)sp - sizeof(struct linux__fpstate)) & ~0xfUL);
    155 		fpsp = (struct linux__fpstate *)sp;
    156 	} else
    157 		fpsp = NULL;
    158 
    159 	/*
    160 	 * Populate the rt_sigframe
    161 	 */
    162 	sp = (char *)
    163 	    ((((long)sp - sizeof(struct linux_rt_sigframe)) & ~0xfUL) - 8);
    164 	sfp = (struct linux_rt_sigframe *)sp;
    165 
    166 	bzero(&sigframe, sizeof(sigframe));
    167 	if (ps->sa_sigdesc[sig].sd_vers != 0)
    168 		sigframe.pretcode =
    169 		    (char *)(u_long)ps->sa_sigdesc[sig].sd_tramp;
    170 	else
    171 		sigframe.pretcode = NULL;
    172 
    173 	/*
    174 	 * The user context
    175 	 */
    176 	sigframe.uc.luc_flags = 0;
    177 	sigframe.uc.luc_link = NULL;
    178 
    179 	/* This is used regardless of SA_ONSTACK in Linux */
    180 	sigframe.uc.luc_stack.ss_sp = l->l_sigstk.ss_sp;
    181 	sigframe.uc.luc_stack.ss_size = l->l_sigstk.ss_size;
    182 	sigframe.uc.luc_stack.ss_flags = 0;
    183 	if (l->l_sigstk.ss_flags & SS_ONSTACK)
    184 		sigframe.uc.luc_stack.ss_flags |= LINUX_SS_ONSTACK;
    185 	if (l->l_sigstk.ss_flags & SS_DISABLE)
    186 		sigframe.uc.luc_stack.ss_flags |= LINUX_SS_DISABLE;
    187 
    188 	sigframe.uc.luc_mcontext.r8 = tf->tf_r8;
    189 	sigframe.uc.luc_mcontext.r9 = tf->tf_r9;
    190 	sigframe.uc.luc_mcontext.r10 = tf->tf_r10;
    191 	sigframe.uc.luc_mcontext.r11 = tf->tf_r11;
    192 	sigframe.uc.luc_mcontext.r12 = tf->tf_r12;
    193 	sigframe.uc.luc_mcontext.r13 = tf->tf_r13;
    194 	sigframe.uc.luc_mcontext.r14 = tf->tf_r14;
    195 	sigframe.uc.luc_mcontext.r15 = tf->tf_r15;
    196 	sigframe.uc.luc_mcontext.rdi = tf->tf_rdi;
    197 	sigframe.uc.luc_mcontext.rsi = tf->tf_rsi;
    198 	sigframe.uc.luc_mcontext.rbp = tf->tf_rbp;
    199 	sigframe.uc.luc_mcontext.rbx = tf->tf_rbx;
    200 	sigframe.uc.luc_mcontext.rdx = tf->tf_rdx;
    201 	sigframe.uc.luc_mcontext.rcx = tf->tf_rcx;
    202 	sigframe.uc.luc_mcontext.rsp = tf->tf_rsp;
    203 	sigframe.uc.luc_mcontext.rip = tf->tf_rip;
    204 	sigframe.uc.luc_mcontext.eflags = tf->tf_rflags;
    205 	sigframe.uc.luc_mcontext.cs = tf->tf_cs;
    206 	sigframe.uc.luc_mcontext.gs = tf->tf_gs;
    207 	sigframe.uc.luc_mcontext.fs = tf->tf_fs;
    208 	sigframe.uc.luc_mcontext.err = tf->tf_err;
    209 	sigframe.uc.luc_mcontext.trapno = tf->tf_trapno;
    210 	native_to_linux_sigset(&lmask, mask);
    211 	sigframe.uc.luc_mcontext.oldmask = lmask.sig[0];
    212 	sigframe.uc.luc_mcontext.cr2 = (long)l->l_addr->u_pcb.pcb_onfault;
    213 	sigframe.uc.luc_mcontext.fpstate = fpsp;
    214 	native_to_linux_sigset(&sigframe.uc.luc_sigmask, mask);
    215 
    216 	/*
    217 	 * the siginfo structure
    218 	 */
    219 	sigframe.info.lsi_signo = native_to_linux_signo[sig];
    220 	sigframe.info.lsi_errno = native_to_linux_errno[ksi->ksi_errno];
    221 	sigframe.info.lsi_code = ksi->ksi_code;
    222 
    223 	/* XXX This is a rought conversion, taken from i386 code */
    224 	switch (sigframe.info.lsi_signo) {
    225 	case LINUX_SIGILL:
    226 	case LINUX_SIGFPE:
    227 	case LINUX_SIGSEGV:
    228 	case LINUX_SIGBUS:
    229 	case LINUX_SIGTRAP:
    230 		sigframe.info._sifields._sigfault._addr = ksi->ksi_addr;
    231 		break;
    232 	case LINUX_SIGCHLD:
    233 		sigframe.info._sifields._sigchld._pid = ksi->ksi_pid;
    234 		sigframe.info._sifields._sigchld._uid = ksi->ksi_uid;
    235 		sigframe.info._sifields._sigchld._utime = ksi->ksi_utime;
    236 		sigframe.info._sifields._sigchld._stime = ksi->ksi_stime;
    237 
    238 		if (WCOREDUMP(ksi->ksi_status)) {
    239 			sigframe.info.lsi_code = LINUX_CLD_DUMPED;
    240 			sigframe.info._sifields._sigchld._status =
    241 			    _WSTATUS(ksi->ksi_status);
    242 		} else if (_WSTATUS(ksi->ksi_status)) {
    243 			sigframe.info.lsi_code = LINUX_CLD_KILLED;
    244 			sigframe.info._sifields._sigchld._status =
    245 			    _WSTATUS(ksi->ksi_status);
    246 		} else {
    247 			sigframe.info.lsi_code = LINUX_CLD_EXITED;
    248 			sigframe.info._sifields._sigchld._status =
    249 			    ((ksi->ksi_status & 0xff00U) >> 8);
    250 		}
    251 		break;
    252 	case LINUX_SIGIO:
    253 		sigframe.info._sifields._sigpoll._band = ksi->ksi_band;
    254 		sigframe.info._sifields._sigpoll._fd = ksi->ksi_fd;
    255 		break;
    256 	default:
    257 		sigframe.info._sifields._sigchld._pid = ksi->ksi_pid;
    258 		sigframe.info._sifields._sigchld._uid = ksi->ksi_uid;
    259 		if ((sigframe.info.lsi_signo == LINUX_SIGALRM) ||
    260 		    (sigframe.info.lsi_signo >= LINUX_SIGRTMIN))
    261 			sigframe.info._sifields._timer._sigval.sival_ptr =
    262 			     ksi->ksi_sigval.sival_ptr;
    263 		break;
    264 	}
    265 
    266 	sendsig_reset(l, sig);
    267 	mutex_exit(&p->p_smutex);
    268 	error = 0;
    269 
    270 	/*
    271 	 * Save FPU state, if any
    272 	 */
    273 	if (fpsp != NULL) {
    274 		(void)process_read_fpregs(l, &fpregs);
    275 		bzero(&fpstate, sizeof(fpstate));
    276 		fpstate.cwd = fpregs.fp_fcw;
    277 		fpstate.swd = fpregs.fp_fsw;
    278 		fpstate.twd = fpregs.fp_ftw;
    279 		fpstate.fop = fpregs.fp_fop;
    280 		fpstate.rip = fpregs.fp_rip;
    281 		fpstate.rdp = fpregs.fp_rdp;
    282 		fpstate.mxcsr = fpregs.fp_mxcsr;
    283 		fpstate.mxcsr_mask = fpregs.fp_mxcsr_mask;
    284 		memcpy(&fpstate.st_space, &fpregs.fp_st,
    285 		    sizeof(fpstate.st_space));
    286 		memcpy(&fpstate.xmm_space, &fpregs.fp_xmm,
    287 		    sizeof(fpstate.xmm_space));
    288 		error = copyout(&fpstate, fpsp, sizeof(fpstate));
    289 	}
    290 
    291 	if (error == 0)
    292 		error = copyout(&sigframe, sp, sizeof(sigframe));
    293 
    294 	mutex_enter(&p->p_smutex);
    295 
    296 	if (error != 0) {
    297 		sigexit(l, SIGILL);
    298 		return;
    299 	}
    300 
    301 	linux_buildcontext(l, catcher, sp);
    302 	tf->tf_rdi = sigframe.info.lsi_signo;
    303 	tf->tf_rax = 0;
    304 	tf->tf_rsi = (long)&sfp->info;
    305 	tf->tf_rdx = (long)&sfp->uc;
    306 
    307 	/*
    308 	 * Remember we use signal stack
    309 	 */
    310 	if (onstack)
    311 		l->l_sigstk.ss_flags |= SS_ONSTACK;
    312 	return;
    313 }
    314 
    315 int
    316 linux_sys_modify_ldt(l, v, retval)
    317         struct lwp *l;
    318         void *v;
    319         register_t *retval;
    320 {
    321 	printf("linux_sys_modify_ldt\n");
    322 	return 0;
    323 }
    324 
    325 int
    326 linux_sys_iopl(l, v, retval)
    327         struct lwp *l;
    328         void *v;
    329         register_t *retval;
    330 {
    331 	return 0;
    332 }
    333 
    334 int
    335 linux_sys_ioperm(l, v, retval)
    336         struct lwp *l;
    337         void *v;
    338         register_t *retval;
    339 {
    340 	return 0;
    341 }
    342 
    343 dev_t
    344 linux_fakedev(dev, raw)
    345         dev_t dev;
    346 	int raw;
    347 {
    348 	return ((minor(dev) & 0xff) | ((major(dev) & 0xfff) << 8)
    349 	    | (((unsigned long long int) (minor(dev) & ~0xff)) << 12)
    350 	    | (((unsigned long long int) (major(dev) & ~0xfff)) << 32));
    351 }
    352 
    353 int
    354 linux_machdepioctl(l, v, retval)
    355         struct lwp *l;
    356         void *v;
    357         register_t *retval;
    358 {
    359 	return 0;
    360 }
    361 
    362 int
    363 linux_sys_rt_sigreturn(l, v, retval)
    364         struct lwp *l;
    365         void *v;
    366         register_t *retval;
    367 {
    368 	struct linux_ucontext *luctx;
    369 	struct trapframe *tf = l->l_md.md_regs;
    370 	struct linux_sigcontext *lsigctx;
    371 	struct linux__fpstate fpstate;
    372 	struct linux_rt_sigframe frame, *fp;
    373 	ucontext_t uctx;
    374 	mcontext_t *mctx;
    375 	struct fxsave64 *fxsave;
    376 	int error;
    377 
    378 	fp = (struct linux_rt_sigframe *)(tf->tf_rsp - 8);
    379 	if ((error = copyin(fp, &frame, sizeof(frame))) != 0) {
    380 		mutex_enter(&l->l_proc->p_smutex);
    381 		sigexit(l, SIGILL);
    382 		return error;
    383 	}
    384 	luctx = &frame.uc;
    385 	lsigctx = &luctx->luc_mcontext;
    386 
    387 	bzero(&uctx, sizeof(uctx));
    388 	mctx = (mcontext_t *)&uctx.uc_mcontext;
    389 	fxsave = (struct fxsave64 *)&mctx->__fpregs;
    390 
    391 	/*
    392 	 * Set the flags. Linux always have CPU, stack and signal state,
    393 	 * FPU is optional. uc_flags is not used to tell what we have.
    394 	 */
    395 	uctx.uc_flags = (_UC_SIGMASK|_UC_CPU|_UC_STACK|_UC_CLRSTACK);
    396 	if (lsigctx->fpstate != NULL)
    397 		uctx.uc_flags |= _UC_FPU;
    398 	uctx.uc_link = NULL;
    399 
    400 	/*
    401 	 * Signal set
    402 	 */
    403 	linux_to_native_sigset(&uctx.uc_sigmask, &luctx->luc_sigmask);
    404 
    405 	/*
    406 	 * CPU state
    407 	 */
    408 	mctx->__gregs[_REG_R8] = lsigctx->r8;
    409 	mctx->__gregs[_REG_R9] = lsigctx->r9;
    410 	mctx->__gregs[_REG_R10] = lsigctx->r10;
    411 	mctx->__gregs[_REG_R11] = lsigctx->r11;
    412 	mctx->__gregs[_REG_R12] = lsigctx->r12;
    413 	mctx->__gregs[_REG_R13] = lsigctx->r13;
    414 	mctx->__gregs[_REG_R14] = lsigctx->r14;
    415 	mctx->__gregs[_REG_R15] = lsigctx->r15;
    416 	mctx->__gregs[_REG_RDI] = lsigctx->rdi;
    417 	mctx->__gregs[_REG_RSI] = lsigctx->rsi;
    418 	mctx->__gregs[_REG_RBP] = lsigctx->rbp;
    419 	mctx->__gregs[_REG_RBX] = lsigctx->rbx;
    420 	mctx->__gregs[_REG_RAX] = tf->tf_rax;
    421 	mctx->__gregs[_REG_RDX] = lsigctx->rdx;
    422 	mctx->__gregs[_REG_RCX] = lsigctx->rcx;
    423 	mctx->__gregs[_REG_RIP] = lsigctx->rip;
    424 	mctx->__gregs[_REG_RFL] = lsigctx->eflags;
    425 	mctx->__gregs[_REG_CS] = lsigctx->cs;
    426 	mctx->__gregs[_REG_GS] = lsigctx->gs;
    427 	mctx->__gregs[_REG_FS] = lsigctx->fs;
    428 	mctx->__gregs[_REG_ERR] = lsigctx->err;
    429 	mctx->__gregs[_REG_TRAPNO] = lsigctx->trapno;
    430 	mctx->__gregs[_REG_ES] = tf->tf_es;
    431 	mctx->__gregs[_REG_DS] = tf->tf_ds;
    432 	mctx->__gregs[_REG_URSP] = lsigctx->rsp; /* XXX */
    433 	mctx->__gregs[_REG_SS] = tf->tf_ss;
    434 
    435 	/*
    436 	 * FPU state
    437 	 */
    438 	if (lsigctx->fpstate != NULL) {
    439 		error = copyin(lsigctx->fpstate, &fpstate, sizeof(fpstate));
    440 		if (error != 0) {
    441 			mutex_enter(&l->l_proc->p_smutex);
    442 			sigexit(l, SIGILL);
    443 			return error;
    444 		}
    445 
    446 		fxsave->fx_fcw = fpstate.cwd;
    447 		fxsave->fx_fsw = fpstate.swd;
    448 		fxsave->fx_ftw = fpstate.twd;
    449 		fxsave->fx_fop = fpstate.fop;
    450 		fxsave->fx_rip = fpstate.rip;
    451 		fxsave->fx_rdp = fpstate.rdp;
    452 		fxsave->fx_mxcsr = fpstate.mxcsr;
    453 		fxsave->fx_mxcsr_mask = fpstate.mxcsr_mask;
    454 		memcpy(&fxsave->fx_st, &fpstate.st_space,
    455 		    sizeof(fxsave->fx_st));
    456 		memcpy(&fxsave->fx_xmm, &fpstate.xmm_space,
    457 		    sizeof(fxsave->fx_xmm));
    458 	}
    459 
    460 	/*
    461 	 * And the stack
    462 	 */
    463 	uctx.uc_stack.ss_flags = 0;
    464 	if (luctx->luc_stack.ss_flags & LINUX_SS_ONSTACK);
    465 		uctx.uc_stack.ss_flags = SS_ONSTACK;
    466 
    467 	if (luctx->luc_stack.ss_flags & LINUX_SS_DISABLE);
    468 		uctx.uc_stack.ss_flags = SS_DISABLE;
    469 
    470 	uctx.uc_stack.ss_sp = luctx->luc_stack.ss_sp;
    471 	uctx.uc_stack.ss_size = luctx->luc_stack.ss_size;
    472 
    473 	/*
    474 	 * And let setucontext deal with that.
    475 	 */
    476 	mutex_enter(&l->l_proc->p_smutex);
    477 	error = setucontext(l, &uctx);
    478 	mutex_exit(&l->l_proc->p_smutex);
    479 
    480 	return error;
    481 }
    482 
    483 int
    484 linux_sys_arch_prctl(l, v, retval)
    485 	struct lwp *l;
    486 	void *v;
    487 	register_t *retval;
    488 {
    489 	struct linux_sys_arch_prctl_args /* {
    490 		syscallarg(int) code;
    491 		syscallarg(unsigned long) addr;
    492 	} */ *uap = v;
    493 	struct pcb *pcb = &l->l_addr->u_pcb;
    494 	struct trapframe *tf = l->l_md.md_regs;
    495 	int error;
    496 	uint64_t taddr;
    497 
    498 	switch(SCARG(uap, code)) {
    499 	case LINUX_ARCH_SET_GS:
    500 		taddr = SCARG(uap, addr);
    501 		if (taddr >= VM_MAXUSER_ADDRESS)
    502 			return EINVAL;
    503 		pcb->pcb_gs = taddr;
    504 		pcb->pcb_flags |= PCB_GS64;
    505 		if (l == curlwp)
    506 			wrmsr(MSR_KERNELGSBASE, taddr);
    507 		break;
    508 
    509 	case LINUX_ARCH_GET_GS:
    510 		if (pcb->pcb_flags & PCB_GS64)
    511 			taddr = pcb->pcb_gs;
    512 		else {
    513 			error = memseg_baseaddr(l, tf->tf_fs, NULL, 0, &taddr);
    514 			if (error != 0)
    515 				return error;
    516 		}
    517 		error = copyout(&taddr, (char *)SCARG(uap, addr), 8);
    518 		if (error != 0)
    519 			return error;
    520 		break;
    521 
    522 	case LINUX_ARCH_SET_FS:
    523 		taddr = SCARG(uap, addr);
    524 		if (taddr >= VM_MAXUSER_ADDRESS)
    525 			return EINVAL;
    526 		pcb->pcb_fs = taddr;
    527 		pcb->pcb_flags |= PCB_FS64;
    528 		if (l == curlwp)
    529 			wrmsr(MSR_FSBASE, taddr);
    530 		break;
    531 
    532 	case LINUX_ARCH_GET_FS:
    533 		if (pcb->pcb_flags & PCB_FS64)
    534 			taddr = pcb->pcb_fs;
    535 		else {
    536 			error = memseg_baseaddr(l, tf->tf_fs, NULL, 0, &taddr);
    537 			if (error != 0)
    538 				return error;
    539 		}
    540 		error = copyout(&taddr, (char *)SCARG(uap, addr), 8);
    541 		if (error != 0)
    542 			return error;
    543 		break;
    544 
    545 	default:
    546 #ifdef DEBUG_LINUX
    547 		printf("linux_sys_arch_prctl: unexpected code %d\n",
    548 		    SCARG(uap, code));
    549 #endif
    550 		return EINVAL;
    551 	}
    552 
    553 	return 0;
    554 }
    555 
    556 const int linux_vsyscall_to_syscall[] = {
    557 	LINUX_SYS_gettimeofday,
    558 	LINUX_SYS_time,
    559 	LINUX_SYS_nosys,
    560 	LINUX_SYS_nosys,
    561 };
    562 
    563 int
    564 linux_usertrap(struct lwp *l, vaddr_t trapaddr, void *arg)
    565 {
    566 	struct trapframe *tf = arg;
    567 	uint64_t retaddr;
    568 	int vsyscallnr;
    569 
    570 	/*
    571 	 * Check for a vsyscall. %rip must be the fault address,
    572 	 * and the address must be in the Linux vsyscall area.
    573 	 * Also, vsyscalls are only done at 1024-byte boundaries.
    574 	 */
    575 
    576 	if (__predict_true(trapaddr < LINUX_VSYSCALL_START))
    577 		return 0;
    578 
    579 	if (trapaddr != tf->tf_rip)
    580 		return 0;
    581 
    582 	if ((tf->tf_rip & (LINUX_VSYSCALL_SIZE - 1)) != 0)
    583 		return 0;
    584 
    585 	vsyscallnr = (tf->tf_rip - LINUX_VSYSCALL_START) / LINUX_VSYSCALL_SIZE;
    586 
    587 	if (vsyscallnr > LINUX_VSYSCALL_MAXNR)
    588 		return 0;
    589 
    590 	/*
    591 	 * Get the return address from the top of the stack,
    592 	 * and fix up the return address.
    593 	 * This assumes the faulting instruction was callq *reg,
    594 	 * which is the only way that vsyscalls are ever entered.
    595 	 */
    596 	if (copyin((void *)tf->tf_rsp, &retaddr, sizeof retaddr) != 0)
    597 		return 0;
    598 	tf->tf_rip = retaddr;
    599 	tf->tf_rax = linux_vsyscall_to_syscall[vsyscallnr];
    600 	tf->tf_rsp += 8;	/* "pop" the return address */
    601 
    602 #if 0
    603 	printf("usertrap: rip %p rsp %p retaddr %p vsys %d sys %d\n",
    604 	    (void *)tf->tf_rip, (void *)tf->tf_rsp, (void *)retaddr,
    605 	    vsyscallnr, (int)tf->tf_rax);
    606 #endif
    607 
    608 	(*l->l_proc->p_md.md_syscall)(tf);
    609 
    610 	return 1;
    611 }
    612 
    613 static void
    614 linux_buildcontext(struct lwp *l, void *catcher, void *f)
    615 {
    616 	struct trapframe *tf = l->l_md.md_regs;
    617 
    618 	tf->tf_ds = GSEL(GUDATA_SEL, SEL_UPL);
    619 	tf->tf_rip = (u_int64_t)catcher;
    620 	tf->tf_cs = GSEL(GUCODE_SEL, SEL_UPL);
    621 	tf->tf_rflags &= ~(PSL_T|PSL_VM|PSL_AC);
    622 	tf->tf_rsp = (u_int64_t)f;
    623 	tf->tf_ss = GSEL(GUDATA_SEL, SEL_UPL);
    624 }
    625 
    626 void *
    627 linux_get_newtls(l)
    628 	struct lwp *l;
    629 {
    630 	struct trapframe *tf = l->l_md.md_regs;
    631 
    632 	return (void *)tf->tf_r8;
    633 }
    634 
    635 int
    636 linux_set_newtls(l, tls)
    637 	struct lwp *l;
    638 	void *tls;
    639 {
    640 	struct linux_sys_arch_prctl_args cup;
    641 	register_t retval;
    642 
    643 	SCARG(&cup, code) = LINUX_ARCH_SET_FS;
    644 	SCARG(&cup, addr) = (unsigned long)tls;
    645 
    646 	return linux_sys_arch_prctl(l, &cup, &retval);
    647 }
    648