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linux32_machdep.c revision 1.45
      1 /*	$NetBSD: linux32_machdep.c,v 1.45 2019/05/19 08:46:15 maxv Exp $ */
      2 
      3 /*-
      4  * Copyright (c) 2006 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 #include <sys/cdefs.h>
     34 __KERNEL_RCSID(0, "$NetBSD: linux32_machdep.c,v 1.45 2019/05/19 08:46:15 maxv Exp $");
     35 
     36 #if defined(_KERNEL_OPT)
     37 #include "opt_user_ldt.h"
     38 #endif
     39 
     40 #include <sys/param.h>
     41 #include <sys/proc.h>
     42 #include <sys/exec.h>
     43 
     44 #include <machine/vmparam.h>
     45 #include <machine/cpufunc.h>
     46 #include <machine/netbsd32_machdep.h>
     47 
     48 #include <x86/fpu.h>
     49 
     50 #include <compat/netbsd32/netbsd32.h>
     51 #include <compat/netbsd32/netbsd32_syscallargs.h>
     52 
     53 #include <compat/linux/common/linux_types.h>
     54 #include <compat/linux/common/linux_emuldata.h>
     55 #include <compat/linux/common/linux_signal.h>
     56 #include <compat/linux/common/linux_errno.h>
     57 #include <compat/linux/common/linux_exec.h>
     58 #include <compat/linux/common/linux_ipc.h>
     59 #include <compat/linux/common/linux_sem.h>
     60 #include <compat/linux/linux_syscallargs.h>
     61 
     62 #include <compat/linux32/common/linux32_types.h>
     63 #include <compat/linux32/common/linux32_errno.h>
     64 #include <compat/linux32/common/linux32_machdep.h>
     65 #include <compat/linux32/common/linux32_signal.h>
     66 #include <compat/linux32/common/linux32_exec.h>
     67 #include <compat/linux32/common/linux32_ipc.h>
     68 #include <compat/linux32/common/linux32_sem.h>
     69 #include <compat/linux32/linux32_syscallargs.h>
     70 
     71 #ifdef DEBUG_LINUX
     72 #define DPRINTF(a) uprintf a
     73 #else
     74 #define DPRINTF(a)
     75 #endif
     76 
     77 extern char linux32_sigcode[];
     78 extern char linux32_rt_sigcode[];
     79 extern char linux32_esigcode[];
     80 
     81 static void linux32_save_ucontext(struct lwp *, struct trapframe *,
     82     const sigset_t *, struct sigaltstack *, struct linux32_ucontext *);
     83 static void linux32_save_sigcontext(struct lwp *, struct trapframe *,
     84     const sigset_t *, struct linux32_sigcontext *);
     85 static void linux32_rt_sendsig(const ksiginfo_t *, const sigset_t *);
     86 static void linux32_old_sendsig(const ksiginfo_t *, const sigset_t *);
     87 static int linux32_restore_sigcontext(struct lwp *,
     88     struct linux32_sigcontext *, register_t *);
     89 
     90 void
     91 linux32_sendsig(const ksiginfo_t *ksi, const sigset_t *mask)
     92 {
     93 	if (SIGACTION(curproc, ksi->ksi_signo).sa_flags & SA_SIGINFO)
     94 		linux32_rt_sendsig(ksi, mask);
     95 	else
     96 		linux32_old_sendsig(ksi, mask);
     97 	return;
     98 }
     99 
    100 void
    101 linux32_old_sendsig(const ksiginfo_t *ksi, const sigset_t *mask)
    102 {
    103 	struct lwp *l = curlwp;
    104 	struct proc *p = l->l_proc;
    105 	struct trapframe *tf;
    106 	struct linux32_sigframe *fp, frame;
    107 	int onstack, error;
    108 	int sig = ksi->ksi_signo;
    109 	sig_t catcher = SIGACTION(p, sig).sa_handler;
    110 	struct sigaltstack *sas = &l->l_sigstk;
    111 
    112 	tf = l->l_md.md_regs;
    113 	/* Do we need to jump onto the signal stack? */
    114 	onstack = (sas->ss_flags & (SS_DISABLE | SS_ONSTACK)) == 0 &&
    115 	    (SIGACTION(p, sig).sa_flags & SA_ONSTACK) != 0;
    116 
    117 
    118 	/* Allocate space for the signal handler context. */
    119 	if (onstack)
    120 		fp = (struct linux32_sigframe *)((char *)sas->ss_sp +
    121 		    sas->ss_size);
    122 	else
    123 		fp = (struct linux32_sigframe *)tf->tf_rsp;
    124 	fp--;
    125 
    126 	DPRINTF(("old: onstack = %d, fp = %p sig = %d rip = 0x%lx\n",
    127 	    onstack, fp, sig, tf->tf_rip));
    128 
    129 	/* Build stack frame for signal trampoline. */
    130 	NETBSD32PTR32(frame.sf_handler, catcher);
    131 	frame.sf_sig = native_to_linux32_signo[sig];
    132 
    133 	linux32_save_sigcontext(l, tf, mask, &frame.sf_sc);
    134 
    135 	sendsig_reset(l, sig);
    136 	mutex_exit(p->p_lock);
    137 	error = copyout(&frame, fp, sizeof(frame));
    138 	mutex_enter(p->p_lock);
    139 
    140 	if (error != 0) {
    141 		/*
    142 		 * Process has trashed its stack; give it an illegal
    143 		 * instruction to halt it in its tracks.
    144 		 */
    145 		sigexit(l, SIGILL);
    146 		/* NOTREACHED */
    147 	}
    148 
    149 	/*
    150 	 * Build context to run handler in.
    151 	 */
    152 	tf->tf_fs = GSEL(GUDATA32_SEL, SEL_UPL) & 0xffffffff;
    153 	tf->tf_es = GSEL(GUDATA32_SEL, SEL_UPL) & 0xffffffff;
    154 	tf->tf_ds = GSEL(GUDATA32_SEL, SEL_UPL) & 0xffffffff;
    155 	tf->tf_rip = ((long)p->p_sigctx.ps_sigcode) & 0xffffffff;
    156 	tf->tf_cs = GSEL(GUCODE32_SEL, SEL_UPL) & 0xffffffff;
    157 	tf->tf_rflags &= ~PSL_CLEARSIG & 0xffffffff;
    158 	tf->tf_rsp = (long)fp & 0xffffffff;
    159 	tf->tf_ss = GSEL(GUDATA32_SEL, SEL_UPL) & 0xffffffff;
    160 
    161 	/* Remember that we're now on the signal stack. */
    162 	if (onstack)
    163 		sas->ss_flags |= SS_ONSTACK;
    164 
    165 	return;
    166 }
    167 
    168 void
    169 linux32_rt_sendsig(const ksiginfo_t *ksi, const sigset_t *mask)
    170 {
    171 	struct lwp *l = curlwp;
    172 	struct proc *p = l->l_proc;
    173 	struct trapframe *tf;
    174 	struct linux32_rt_sigframe *fp, frame;
    175 	int onstack, error;
    176 	linux32_siginfo_t *lsi;
    177 	int sig = ksi->ksi_signo;
    178 	sig_t catcher = SIGACTION(p, sig).sa_handler;
    179 	struct sigaltstack *sas = &l->l_sigstk;
    180 
    181 	tf = l->l_md.md_regs;
    182 	/* Do we need to jump onto the signal stack? */
    183 	onstack = (sas->ss_flags & (SS_DISABLE | SS_ONSTACK)) == 0 &&
    184 	    (SIGACTION(p, sig).sa_flags & SA_ONSTACK) != 0;
    185 
    186 
    187 	/* Allocate space for the signal handler context. */
    188 	if (onstack)
    189 		fp = (struct linux32_rt_sigframe *)((char *)sas->ss_sp +
    190 		    sas->ss_size);
    191 	else
    192 		fp = (struct linux32_rt_sigframe *)tf->tf_rsp;
    193 	fp--;
    194 
    195 	/* Build stack frame for signal trampoline. */
    196 	NETBSD32PTR32(frame.sf_handler, catcher);
    197 	frame.sf_sig = native_to_linux32_signo[sig];
    198 	NETBSD32PTR32(frame.sf_sip, &fp->sf_si);
    199 	NETBSD32PTR32(frame.sf_ucp, &fp->sf_uc);
    200 
    201 	DPRINTF(("rt: onstack = %d, fp = %p sig = %d rip = 0x%lx\n",
    202 	    onstack, fp, sig, tf->tf_rip));
    203 
    204 	lsi = &frame.sf_si;
    205 	(void)memset(lsi, 0, sizeof(frame.sf_si));
    206 	lsi->lsi_errno = native_to_linux32_errno[ksi->ksi_errno];
    207 	lsi->lsi_code = native_to_linux_si_code(ksi->ksi_code);
    208 	lsi->lsi_signo = frame.sf_sig;
    209 	switch (lsi->lsi_signo) {
    210 	case LINUX32_SIGILL:
    211 	case LINUX32_SIGFPE:
    212 	case LINUX32_SIGSEGV:
    213 	case LINUX32_SIGBUS:
    214 	case LINUX32_SIGTRAP:
    215 		NETBSD32PTR32(lsi->lsi_addr, ksi->ksi_addr);
    216 		break;
    217 	case LINUX32_SIGCHLD:
    218 		lsi->lsi_uid = ksi->ksi_uid;
    219 		lsi->lsi_pid = ksi->ksi_pid;
    220 		lsi->lsi_utime = ksi->ksi_utime;
    221 		lsi->lsi_stime = ksi->ksi_stime;
    222 		lsi->lsi_status = native_to_linux_si_status(ksi->ksi_code,
    223 		    ksi->ksi_status);
    224 		break;
    225 	case LINUX32_SIGIO:
    226 		lsi->lsi_band = ksi->ksi_band;
    227 		lsi->lsi_fd = ksi->ksi_fd;
    228 		break;
    229 	default:
    230 		lsi->lsi_uid = ksi->ksi_uid;
    231 		lsi->lsi_pid = ksi->ksi_pid;
    232 		if (lsi->lsi_signo == LINUX32_SIGALRM ||
    233 		    lsi->lsi_signo >= LINUX32_SIGRTMIN)
    234 			NETBSD32PTR32(lsi->lsi_value.sival_ptr,
    235 			     ksi->ksi_value.sival_ptr);
    236 		break;
    237 	}
    238 
    239 	/* Save register context. */
    240 	linux32_save_ucontext(l, tf, mask, sas, &frame.sf_uc);
    241 	sendsig_reset(l, sig);
    242 	mutex_exit(p->p_lock);
    243 	error = copyout(&frame, fp, sizeof(frame));
    244 	mutex_enter(p->p_lock);
    245 
    246 	if (error != 0) {
    247 		/*
    248 		 * Process has trashed its stack; give it an illegal
    249 		 * instruction to halt it in its tracks.
    250 		 */
    251 		sigexit(l, SIGILL);
    252 		/* NOTREACHED */
    253 	}
    254 
    255 	/*
    256 	 * Build context to run handler in.
    257 	 */
    258 	tf->tf_fs = GSEL(GUDATA32_SEL, SEL_UPL) & 0xffffffff;
    259 	tf->tf_es = GSEL(GUDATA32_SEL, SEL_UPL) & 0xffffffff;
    260 	tf->tf_ds = GSEL(GUDATA32_SEL, SEL_UPL) & 0xffffffff;
    261 	tf->tf_rip = (((long)p->p_sigctx.ps_sigcode) +
    262 	    (linux32_rt_sigcode - linux32_sigcode)) & 0xffffffff;
    263 	tf->tf_cs = GSEL(GUCODE32_SEL, SEL_UPL) & 0xffffffff;
    264 	tf->tf_rflags &= ~PSL_CLEARSIG & 0xffffffff;
    265 	tf->tf_rsp = (long)fp & 0xffffffff;
    266 	tf->tf_ss = GSEL(GUDATA32_SEL, SEL_UPL) & 0xffffffff;
    267 
    268 	/* Remember that we're now on the signal stack. */
    269 	if (onstack)
    270 		sas->ss_flags |= SS_ONSTACK;
    271 
    272 	return;
    273 }
    274 
    275 void
    276 linux32_setregs(struct lwp *l, struct exec_package *pack, u_long stack)
    277 {
    278 	struct pcb *pcb = lwp_getpcb(l);
    279 	struct trapframe *tf;
    280 	struct proc *p = l->l_proc;
    281 
    282 #if defined(USER_LDT)
    283 	pmap_ldt_cleanup(l);
    284 #endif
    285 
    286 	netbsd32_adjust_limits(p);
    287 
    288 	fpu_clear(l, __Linux_NPXCW__);
    289 
    290 	kpreempt_disable();
    291 	pcb->pcb_flags = PCB_COMPAT32;
    292 	p->p_flag |= PK_32;
    293 	l->l_md.md_flags = MDL_COMPAT32;	/* force iret not sysret */
    294 	cpu_segregs32_zero(l);
    295 	cpu_fsgs_reload(l, GSEL(GUDATA32_SEL, SEL_UPL),
    296 	    GSEL(GUDATA32_SEL, SEL_UPL));
    297 	kpreempt_enable();
    298 
    299 	tf = l->l_md.md_regs;
    300 	tf->tf_rax = 0;
    301 	tf->tf_rbx = (u_int32_t)p->p_psstrp;
    302 	tf->tf_rcx = pack->ep_entry & 0xffffffff;
    303 	tf->tf_rdx = 0;
    304 	tf->tf_rsi = 0;
    305 	tf->tf_rdi = 0;
    306 	tf->tf_rbp = 0;
    307 	tf->tf_rsp = stack & 0xffffffff;
    308 	tf->tf_r8 = 0;
    309 	tf->tf_r9 = 0;
    310 	tf->tf_r10 = 0;
    311 	tf->tf_r11 = 0;
    312 	tf->tf_r12 = 0;
    313 	tf->tf_r13 = 0;
    314 	tf->tf_r14 = 0;
    315 	tf->tf_r15 = 0;
    316 	tf->tf_rip = pack->ep_entry & 0xffffffff;
    317 	tf->tf_rflags = PSL_USERSET;
    318 	tf->tf_cs = GSEL(GUCODE32_SEL, SEL_UPL);
    319 	tf->tf_ss = GSEL(GUDATA32_SEL, SEL_UPL);
    320 	tf->tf_ds = GSEL(GUDATA32_SEL, SEL_UPL);
    321 	tf->tf_es = GSEL(GUDATA32_SEL, SEL_UPL);
    322 }
    323 
    324 static void
    325 linux32_save_ucontext(struct lwp *l, struct trapframe *tf,
    326     const sigset_t *mask, struct sigaltstack *sas, struct linux32_ucontext *uc)
    327 {
    328 
    329 	uc->uc_flags = 0;
    330 	NETBSD32PTR32(uc->uc_link, NULL);
    331 	native_to_linux32_sigaltstack(&uc->uc_stack, sas);
    332 	linux32_save_sigcontext(l, tf, mask, &uc->uc_mcontext);
    333 	native_to_linux32_sigset(&uc->uc_sigmask, mask);
    334 	(void)memset(&uc->uc_fpregs_mem, 0, sizeof(uc->uc_fpregs_mem));
    335 }
    336 
    337 static void
    338 linux32_save_sigcontext(struct lwp *l, struct trapframe *tf,
    339 			const sigset_t *mask, struct linux32_sigcontext *sc)
    340 {
    341 	struct pcb *pcb = lwp_getpcb(l);
    342 
    343 	/* Save register context. */
    344 	sc->sc_gs = tf->tf_gs & 0xFFFF;
    345 	sc->sc_fs = tf->tf_fs & 0xFFFF;
    346 	sc->sc_es = tf->tf_es & 0xFFFF;
    347 	sc->sc_ds = tf->tf_ds & 0xFFFF;
    348 	sc->sc_eflags = tf->tf_rflags;
    349 	sc->sc_edi = tf->tf_rdi;
    350 	sc->sc_esi = tf->tf_rsi;
    351 	sc->sc_esp = tf->tf_rsp;
    352 	sc->sc_ebp = tf->tf_rbp;
    353 	sc->sc_ebx = tf->tf_rbx;
    354 	sc->sc_edx = tf->tf_rdx;
    355 	sc->sc_ecx = tf->tf_rcx;
    356 	sc->sc_eax = tf->tf_rax;
    357 	sc->sc_eip = tf->tf_rip;
    358 	sc->sc_cs = tf->tf_cs & 0xFFFF;
    359 	sc->sc_esp_at_signal = tf->tf_rsp;
    360 	sc->sc_ss = tf->tf_ss & 0xFFFF;
    361 	sc->sc_err = tf->tf_err;
    362 	sc->sc_trapno = tf->tf_trapno;
    363 	sc->sc_cr2 = pcb->pcb_cr2;
    364 	NETBSD32PTR32(sc->sc_387, NULL);
    365 
    366 	/* Save signal stack. */
    367 	/* Linux doesn't save the onstack flag in sigframe */
    368 
    369 	/* Save signal mask. */
    370 	native_to_linux32_old_sigset(&sc->sc_mask, mask);
    371 }
    372 
    373 int
    374 linux32_sys_sigreturn(struct lwp *l,
    375     const struct linux32_sys_sigreturn_args *uap, register_t *retval)
    376 {
    377 	/* {
    378 		syscallarg(linux32_sigcontextp_t) scp;
    379 	} */
    380 	struct linux32_sigcontext ctx;
    381 	int error;
    382 
    383 	if ((error = copyin(SCARG_P32(uap, scp), &ctx, sizeof(ctx))) != 0)
    384 		return error;
    385 
    386 	return linux32_restore_sigcontext(l, &ctx, retval);
    387 }
    388 
    389 int
    390 linux32_sys_rt_sigreturn(struct lwp *l,
    391     const struct linux32_sys_rt_sigreturn_args *uap, register_t *retval)
    392 {
    393 	/* {
    394 		syscallarg(linux32_ucontextp_t) ucp;
    395 	} */
    396 	struct linux32_ucontext ctx;
    397 	int error;
    398 
    399 	if ((error = copyin(SCARG_P32(uap, ucp), &ctx, sizeof(ctx))) != 0)
    400 		return error;
    401 
    402 	return linux32_restore_sigcontext(l, &ctx.uc_mcontext, retval);
    403 }
    404 
    405 static int
    406 linux32_restore_sigcontext(struct lwp *l, struct linux32_sigcontext *scp,
    407 			register_t *retval)
    408 {
    409 	struct trapframe *tf;
    410 	struct proc *p = l->l_proc;
    411 	struct sigaltstack *sas = &l->l_sigstk;
    412 	struct pcb *pcb;
    413 	sigset_t mask;
    414 	ssize_t ss_gap;
    415 	register_t fssel, gssel;
    416 
    417 	/* Restore register context. */
    418 	tf = l->l_md.md_regs;
    419 	pcb = lwp_getpcb(l);
    420 	DPRINTF(("sigreturn enter rsp=0x%lx rip=0x%lx\n", tf->tf_rsp,
    421 		 tf->tf_rip));
    422 
    423 	/*
    424 	 * Check for security violations.
    425 	 */
    426 	if (((scp->sc_eflags ^ tf->tf_rflags) & PSL_USERSTATIC) != 0)
    427 		return EINVAL;
    428 	if (!VALID_USER_CSEL32(scp->sc_cs))
    429 		return EINVAL;
    430 
    431 	if (scp->sc_fs != 0 && !VALID_USER_DSEL32(scp->sc_fs) &&
    432 	    !(VALID_USER_FSEL32(scp->sc_fs) && pcb->pcb_fs != 0))
    433 		return EINVAL;
    434 
    435 	if (scp->sc_gs != 0 && !VALID_USER_DSEL32(scp->sc_gs) &&
    436 	    !(VALID_USER_GSEL32(scp->sc_gs) && pcb->pcb_gs != 0))
    437 		return EINVAL;
    438 
    439 	if (scp->sc_es != 0 && !VALID_USER_DSEL32(scp->sc_es))
    440 		return EINVAL;
    441 
    442 	if (!VALID_USER_DSEL32(scp->sc_ds) ||
    443 	    !VALID_USER_DSEL32(scp->sc_ss))
    444 		return EINVAL;
    445 
    446 	if (scp->sc_eip >= VM_MAXUSER_ADDRESS32)
    447 		return EINVAL;
    448 
    449 	gssel = (register_t)scp->sc_gs & 0xffff;
    450 	fssel = (register_t)scp->sc_fs & 0xffff;
    451 	cpu_fsgs_reload(l, fssel, gssel);
    452 	tf->tf_es = (register_t)scp->sc_es & 0xffff;
    453 	tf->tf_ds = (register_t)scp->sc_ds & 0xffff;
    454 	tf->tf_rflags &= ~PSL_USER;
    455 	tf->tf_rflags |= ((register_t)scp->sc_eflags & PSL_USER);
    456 	tf->tf_rdi = (register_t)scp->sc_edi & 0xffffffff;
    457 	tf->tf_rsi = (register_t)scp->sc_esi & 0xffffffff;
    458 	tf->tf_rbp = (register_t)scp->sc_ebp & 0xffffffff;
    459 	tf->tf_rbx = (register_t)scp->sc_ebx & 0xffffffff;
    460 	tf->tf_rdx = (register_t)scp->sc_edx & 0xffffffff;
    461 	tf->tf_rcx = (register_t)scp->sc_ecx & 0xffffffff;
    462 	tf->tf_rax = (register_t)scp->sc_eax & 0xffffffff;
    463 	tf->tf_rip = (register_t)scp->sc_eip & 0xffffffff;
    464 	tf->tf_cs = (register_t)scp->sc_cs & 0xffff;
    465 	tf->tf_rsp = (register_t)scp->sc_esp_at_signal & 0xffffffff;
    466 	tf->tf_ss = (register_t)scp->sc_ss & 0xffff;
    467 
    468 	mutex_enter(p->p_lock);
    469 
    470 	/* Restore signal stack. */
    471 	ss_gap = (ssize_t)
    472 	    ((char *)NETBSD32IPTR64(scp->sc_esp_at_signal)
    473 	     - (char *)sas->ss_sp);
    474 	if (ss_gap >= 0 && ss_gap < sas->ss_size)
    475 		sas->ss_flags |= SS_ONSTACK;
    476 	else
    477 		sas->ss_flags &= ~SS_ONSTACK;
    478 
    479 	/* Restore signal mask. */
    480 	linux32_old_to_native_sigset(&mask, &scp->sc_mask);
    481 	(void) sigprocmask1(l, SIG_SETMASK, &mask, 0);
    482 
    483 	mutex_exit(p->p_lock);
    484 
    485 	DPRINTF(("linux32_sigreturn: rip = 0x%lx, rsp = 0x%lx, flags = 0x%lx\n",
    486 	    tf->tf_rip, tf->tf_rsp, tf->tf_rflags));
    487 	return EJUSTRETURN;
    488 }
    489 
    490 int
    491 linux32_sys_set_thread_area(struct lwp *l,
    492     const struct linux32_sys_set_thread_area_args *uap, register_t *retval)
    493 {
    494 	/* {
    495 		syscallarg(linux32_user_descp_t) desc;
    496 	} */
    497 
    498 	return linux_lwp_setprivate(l, SCARG_P32(uap, desc));
    499 }
    500 
    501 int
    502 linux32_sys_get_thread_area(struct lwp *l,
    503     const struct linux32_sys_get_thread_area_args *uap, register_t *retval)
    504 {
    505 	/* {
    506 		syscallarg(linux32_user_descp_t) desc;
    507 	} */
    508 
    509 	/* glibc doesn't actually call this. */
    510 	return ENOSYS;
    511 }
    512 
    513 int
    514 linux32_sys_modify_ldt(struct lwp *l, const struct linux32_sys_modify_ldt_args *uap, register_t *retval)
    515 {
    516 	/* {
    517 		syscallarg(int) func;
    518 		syscallarg(netbsd32_charp) ptr;
    519 		syscallarg(netbsd32_size_t) bytecount;
    520 	} */
    521 	struct linux_sys_modify_ldt_args ua;
    522 
    523 	NETBSD32TO64_UAP(func);
    524 	NETBSD32TOP_UAP(ptr, void *);
    525 	NETBSD32TOX_UAP(bytecount, size_t);
    526 	return linux_sys_modify_ldt(l, &ua, retval);
    527 }
    528