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      1 /*	$NetBSD: linux_machdep.c,v 1.52 2021/09/07 11:43:03 riastradh Exp $	*/
      2 
      3 /*-
      4  * Copyright (c) 1998 The NetBSD Foundation, Inc.
      5  * All rights reserved.
      6  *
      7  * This code is derived from software contributed to The NetBSD Foundation
      8  * by Eric Haszlakiewicz.
      9  *
     10  * Redistribution and use in source and binary forms, with or without
     11  * modification, are permitted provided that the following conditions
     12  * are met:
     13  * 1. Redistributions of source code must retain the above copyright
     14  *    notice, this list of conditions and the following disclaimer.
     15  * 2. Redistributions in binary form must reproduce the above copyright
     16  *    notice, this list of conditions and the following disclaimer in the
     17  *    documentation and/or other materials provided with the distribution.
     18  *
     19  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
     20  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
     21  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
     22  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
     23  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
     24  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
     25  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
     26  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
     27  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
     28  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
     29  * POSSIBILITY OF SUCH DAMAGE.
     30  *
     31  * Based on sys/arch/i386/i386/linux_machdep.c:
     32  *	linux_machdep.c,v 1.42 1998/09/11 12:50:06 mycroft Exp
     33  *	written by Frank van der Linden
     34  *
     35  */
     36 
     37 #include <sys/cdefs.h>
     38 __KERNEL_RCSID(0, "$NetBSD: linux_machdep.c,v 1.52 2021/09/07 11:43:03 riastradh Exp $");
     39 
     40 #include <sys/param.h>
     41 #include <sys/systm.h>
     42 #include <sys/signalvar.h>
     43 #include <sys/kernel.h>
     44 #include <sys/proc.h>
     45 #include <sys/buf.h>
     46 #include <sys/reboot.h>
     47 #include <sys/conf.h>
     48 #include <sys/exec.h>
     49 #include <sys/file.h>
     50 #include <sys/callout.h>
     51 #include <sys/mbuf.h>
     52 #include <sys/msgbuf.h>
     53 #include <sys/mount.h>
     54 #include <sys/vnode.h>
     55 #include <sys/device.h>
     56 #include <sys/syscallargs.h>
     57 #include <sys/filedesc.h>
     58 #include <sys/exec_elf.h>
     59 #include <sys/ioctl.h>
     60 #include <sys/kauth.h>
     61 
     62 #include <uvm/uvm_extern.h>
     63 
     64 #include <compat/linux/common/linux_types.h>
     65 #include <compat/linux/common/linux_signal.h>
     66 #include <compat/linux/common/linux_siginfo.h>
     67 #include <compat/linux/common/linux_util.h>
     68 #include <compat/linux/common/linux_ioctl.h>
     69 #include <compat/linux/common/linux_exec.h>
     70 #include <compat/linux/common/linux_machdep.h>
     71 #include <compat/linux/common/linux_emuldata.h>
     72 
     73 #include <compat/linux/linux_syscallargs.h>
     74 
     75 #include <machine/alpha.h>
     76 #include <machine/reg.h>
     77 
     78 #if defined(_KERNEL_OPT)
     79 #include "wsdisplay.h"
     80 #endif
     81 #if (NWSDISPLAY >0)
     82 #include <dev/wscons/wsdisplay_usl_io.h>
     83 #endif
     84 #ifdef DEBUG
     85 #include <machine/sigdebug.h>
     86 #endif
     87 
     88 /*
     89  * Deal with some alpha-specific things in the Linux emulation code.
     90  */
     91 
     92 void
     93 linux_setregs(struct lwp *l, struct exec_package *epp, vaddr_t stack)
     94 {
     95 #ifdef DEBUG
     96 	struct trapframe *tfp = l->l_md.md_tf;
     97 #endif
     98 
     99 	setregs(l, epp, stack);
    100 #ifdef DEBUG
    101 	/*
    102 	 * Linux has registers set to zero on entry; for DEBUG kernels
    103 	 * the alpha setregs() fills registers with 0xbabefacedeadbeef.
    104 	 */
    105 	memset(tfp->tf_regs, 0, FRAME_SIZE * sizeof tfp->tf_regs[0]);
    106 #endif
    107 }
    108 
    109 void
    110 setup_linux_rt_sigframe(struct trapframe *tf, const ksiginfo_t *ksi,
    111     const sigset_t *mask)
    112 {
    113 	struct lwp *l = curlwp;
    114 	struct proc *p = l->l_proc;
    115 	struct linux_rt_sigframe *sfp, sigframe;
    116 	int onstack, error;
    117 	int fsize, rndfsize;
    118 	int sig = ksi->ksi_signo;
    119 	extern char linux_rt_sigcode[], linux_rt_esigcode[];
    120 
    121 	/* Do we need to jump onto the signal stack? */
    122 	onstack = (l->l_sigstk.ss_flags & (SS_DISABLE | SS_ONSTACK)) == 0 &&
    123 		  (SIGACTION(p, sig).sa_flags & SA_ONSTACK) != 0;
    124 
    125 	/* Allocate space for the signal handler context.  */
    126 	fsize = sizeof(struct linux_rt_sigframe);
    127 	rndfsize = ((fsize + 15) / 16) * 16;
    128 
    129 	if (onstack)
    130 		sfp = (struct linux_rt_sigframe *)
    131 		    ((char *)l->l_sigstk.ss_sp + l->l_sigstk.ss_size);
    132 	else
    133 		sfp = (struct linux_rt_sigframe *)(alpha_pal_rdusp());
    134 	sfp = (struct linux_rt_sigframe *)((char *)sfp - rndfsize);
    135 
    136 #ifdef DEBUG
    137 	if ((sigdebug & SDB_KSTACK) && (p->p_pid == sigpid))
    138 		printf("linux_sendsig(%d): sig %d ssp %p usp %p\n", p->p_pid,
    139 		    sig, &onstack, sfp);
    140 #endif /* DEBUG */
    141 
    142 	memset(&sigframe, 0, sizeof(sigframe));
    143 
    144 	/*
    145 	 * Build the signal context to be used by sigreturn.
    146 	 */
    147 	memset(&sigframe.uc, 0, sizeof(struct linux_ucontext));
    148 	sigframe.uc.uc_mcontext.sc_onstack = onstack;
    149 
    150 	/* Setup potentially partial signal mask in sc_mask. */
    151 	/* But get all of it in uc_sigmask */
    152 	native_to_linux_old_sigset(&sigframe.uc.uc_mcontext.sc_mask, mask);
    153 	native_to_linux_sigset(&sigframe.uc.uc_sigmask, mask);
    154 
    155 	sigframe.uc.uc_mcontext.sc_pc = tf->tf_regs[FRAME_PC];
    156 	sigframe.uc.uc_mcontext.sc_ps = ALPHA_PSL_USERMODE;
    157 	frametoreg(tf, (struct reg *)sigframe.uc.uc_mcontext.sc_regs);
    158 	sigframe.uc.uc_mcontext.sc_regs[R_SP] = alpha_pal_rdusp();
    159 
    160 	fpu_load();
    161 	alpha_pal_wrfen(1);
    162 	sigframe.uc.uc_mcontext.sc_fpcr = alpha_read_fpcr();
    163 	sigframe.uc.uc_mcontext.sc_fp_control = alpha_read_fp_c(l);
    164 	alpha_pal_wrfen(0);
    165 
    166 	sigframe.uc.uc_mcontext.sc_traparg_a0 = tf->tf_regs[FRAME_A0];
    167 	sigframe.uc.uc_mcontext.sc_traparg_a1 = tf->tf_regs[FRAME_A1];
    168 	sigframe.uc.uc_mcontext.sc_traparg_a2 = tf->tf_regs[FRAME_A2];
    169 	native_to_linux_siginfo(&sigframe.info, &ksi->ksi_info);
    170 	sendsig_reset(l, sig);
    171 	mutex_exit(p->p_lock);
    172 	error = copyout((void *)&sigframe, (void *)sfp, fsize);
    173 	mutex_enter(p->p_lock);
    174 
    175 	if (error != 0) {
    176 #ifdef DEBUG
    177 		if ((sigdebug & SDB_KSTACK) && p->p_pid == sigpid)
    178 			printf("sendsig(%d): copyout failed on sig %d\n",
    179 			    p->p_pid, sig);
    180 #endif
    181 		/*
    182 		 * Process has trashed its stack; give it an illegal
    183 		 * instruction to halt it in its tracks.
    184 		 */
    185 		sigexit(l, SIGILL);
    186 		/* NOTREACHED */
    187 	}
    188 
    189 	/* Pass pointers to siginfo and ucontext in the regs */
    190 	tf->tf_regs[FRAME_A1] = (unsigned long)&sfp->info;
    191 	tf->tf_regs[FRAME_A2] = (unsigned long)&sfp->uc;
    192 
    193 	/* Address of trampoline code.  End up at this PC after mi_switch */
    194 	tf->tf_regs[FRAME_PC] =
    195 	    (u_int64_t)(p->p_psstrp - (linux_rt_esigcode - linux_rt_sigcode));
    196 
    197 	/* Adjust the stack */
    198 	alpha_pal_wrusp((unsigned long)sfp);
    199 
    200 	/* Remember that we're now on the signal stack. */
    201 	if (onstack)
    202 		l->l_sigstk.ss_flags |= SS_ONSTACK;
    203 }
    204 
    205 void setup_linux_sigframe(struct trapframe *tf, const ksiginfo_t *ksi,
    206     const sigset_t *mask)
    207 {
    208 	struct lwp *l = curlwp;
    209 	struct proc *p = l->l_proc;
    210 	struct linux_sigframe *sfp, sigframe;
    211 	int onstack, error;
    212 	int fsize, rndfsize;
    213 	int sig = ksi->ksi_signo;
    214 	extern char linux_sigcode[], linux_esigcode[];
    215 
    216 	/* Do we need to jump onto the signal stack? */
    217 	onstack = (l->l_sigstk.ss_flags & (SS_DISABLE | SS_ONSTACK)) == 0 &&
    218 		  (SIGACTION(p, sig).sa_flags & SA_ONSTACK) != 0;
    219 
    220 	/* Allocate space for the signal handler context.  */
    221 	fsize = sizeof(struct linux_sigframe);
    222 	rndfsize = ((fsize + 15) / 16) * 16;
    223 
    224 	if (onstack)
    225 		sfp = (struct linux_sigframe *)
    226 		    ((char *)l->l_sigstk.ss_sp + l->l_sigstk.ss_size);
    227 	else
    228 		sfp = (struct linux_sigframe *)(alpha_pal_rdusp());
    229 	sfp = (struct linux_sigframe *)((char *)sfp - rndfsize);
    230 
    231 #ifdef DEBUG
    232 	if ((sigdebug & SDB_KSTACK) && (p->p_pid == sigpid))
    233 		printf("linux_sendsig(%d): sig %d ssp %p usp %p\n", p->p_pid,
    234 		    sig, &onstack, sfp);
    235 #endif /* DEBUG */
    236 
    237 	memset(&sigframe, 0, sizeof(sigframe));
    238 
    239 	/*
    240 	 * Build the signal context to be used by sigreturn.
    241 	 */
    242 	memset(&sigframe.sf_sc, 0, sizeof(struct linux_sigcontext));
    243 	sigframe.sf_sc.sc_onstack = onstack;
    244 	native_to_linux_old_sigset(&sigframe.sf_sc.sc_mask, mask);
    245 	sigframe.sf_sc.sc_pc = tf->tf_regs[FRAME_PC];
    246 	sigframe.sf_sc.sc_ps = ALPHA_PSL_USERMODE;
    247 	frametoreg(tf, (struct reg *)sigframe.sf_sc.sc_regs);
    248 	sigframe.sf_sc.sc_regs[R_SP] = alpha_pal_rdusp();
    249 
    250 	if (fpu_valid_p(l)) {
    251 		struct pcb *pcb = lwp_getpcb(l);
    252 
    253 		fpu_save(l);
    254 		sigframe.sf_sc.sc_fpcr = pcb->pcb_fp.fpr_cr;
    255 	}
    256 	/* XXX ownedfp ? etc...? */
    257 
    258 	sigframe.sf_sc.sc_traparg_a0 = tf->tf_regs[FRAME_A0];
    259 	sigframe.sf_sc.sc_traparg_a1 = tf->tf_regs[FRAME_A1];
    260 	sigframe.sf_sc.sc_traparg_a2 = tf->tf_regs[FRAME_A2];
    261 
    262 	sendsig_reset(l, sig);
    263 	mutex_exit(p->p_lock);
    264 	error = copyout((void *)&sigframe, (void *)sfp, fsize);
    265 	mutex_enter(p->p_lock);
    266 
    267 	if (error != 0) {
    268 #ifdef DEBUG
    269 		if ((sigdebug & SDB_KSTACK) && p->p_pid == sigpid)
    270 			printf("sendsig(%d): copyout failed on sig %d\n",
    271 			    p->p_pid, sig);
    272 #endif
    273 		/*
    274 		 * Process has trashed its stack; give it an illegal
    275 		 * instruction to halt it in its tracks.
    276 		 */
    277 		sigexit(l, SIGILL);
    278 		/* NOTREACHED */
    279 	}
    280 
    281 	/* Pass pointers to sigcontext in the regs */
    282 	tf->tf_regs[FRAME_A1] = 0;
    283 	tf->tf_regs[FRAME_A2] = (unsigned long)&sfp->sf_sc;
    284 
    285 	/* Address of trampoline code.  End up at this PC after mi_switch */
    286 	tf->tf_regs[FRAME_PC] =
    287 	    (u_int64_t)(p->p_psstrp - (linux_esigcode - linux_sigcode));
    288 
    289 	/* Adjust the stack */
    290 	alpha_pal_wrusp((unsigned long)sfp);
    291 
    292 	/* Remember that we're now on the signal stack. */
    293 	if (onstack)
    294 		l->l_sigstk.ss_flags |= SS_ONSTACK;
    295 }
    296 
    297 /*
    298  * Send an interrupt to process.
    299  *
    300  * Stack is set up to allow sigcode stored
    301  * in u. to call routine, followed by kcall
    302  * to sigreturn routine below.  After sigreturn
    303  * resets the signal mask, the stack, and the
    304  * frame pointer, it returns to the user
    305  * specified pc, psl.
    306  */
    307 void
    308 linux_sendsig(const ksiginfo_t *ksi, const sigset_t *mask)
    309 {
    310 	struct lwp *l = curlwp;
    311 	struct proc *p = l->l_proc;
    312 	struct trapframe *tf = l->l_md.md_tf;
    313 	const int sig = ksi->ksi_signo;
    314 	sig_t catcher = SIGACTION(p, sig).sa_handler;
    315 #ifdef notyet
    316 	struct linux_emuldata *edp;
    317 
    318 	/* Setup the signal frame (and part of the trapframe) */
    319 	/*OLD: if (p->p_sigacts->ps_siginfo & sigmask(sig))*/
    320 /*	XXX XAX this is broken now.  need someplace to store what
    321 	XXX XAX kind of signal handler a signal has.*/
    322 #if 0
    323 	edp = (struct linux_emuldata *)p->p_emuldata;
    324 #else
    325 	edp = 0;
    326 #endif
    327 	if (edp && sigismember(&edp->ps_siginfo, sig))
    328 		setup_linux_rt_sigframe(tf, ksi, mask);
    329 	else
    330 #endif /* notyet */
    331 		setup_linux_sigframe(tf, ksi, mask);
    332 
    333 	/* Signal handler for trampoline code */
    334 	tf->tf_regs[FRAME_T12] = (u_int64_t)catcher;
    335 	tf->tf_regs[FRAME_A0] = native_to_linux_signo[sig];
    336 
    337 	/*
    338 	 * Linux has a custom restorer option.  To support it we would
    339 	 * need to store an array of restorers and a sigcode block
    340 	 * which knew to use it.  Doesn't seem worth the trouble.
    341 	 * -erh
    342 	 */
    343 
    344 #ifdef DEBUG
    345 	if (sigdebug & SDB_FOLLOW)
    346 		printf("sendsig(%d): pc %lx, catcher %lx\n", l->l_proc->p_pid,
    347 		    tf->tf_regs[FRAME_PC], tf->tf_regs[FRAME_A3]);
    348 	if ((sigdebug & SDB_KSTACK) && l->l_proc->p_pid == sigpid)
    349 		printf("sendsig(%d): sig %d returns\n", l->l_proc->p_pid, sig);
    350 #endif
    351 }
    352 
    353 /*
    354  * System call to cleanup state after a signal
    355  * has been taken.  Reset signal mask and
    356  * stack state from context left by sendsig (above).
    357  * Return to previous pc as specified by context
    358  * left by sendsig.
    359  * Linux real-time signals use a different sigframe,
    360  * but the sigcontext is the same.
    361  */
    362 
    363 int
    364 linux_restore_sigcontext(struct lwp *l, struct linux_sigcontext context,
    365 			 sigset_t *mask)
    366 {
    367 	struct proc *p = l->l_proc;
    368 	struct pcb *pcb;
    369 
    370 	/*
    371 	 * Linux doesn't (yet) have alternate signal stacks.
    372 	 * However, the OSF/1 sigcontext which they use has
    373 	 * an onstack member.  This could be needed in the future.
    374 	 */
    375 	mutex_enter(p->p_lock);
    376 	if (context.sc_onstack & LINUX_SA_ONSTACK)
    377 	    l->l_sigstk.ss_flags |= SS_ONSTACK;
    378 	else
    379 	    l->l_sigstk.ss_flags &= ~SS_ONSTACK;
    380 
    381 	/* Reset the signal mask */
    382 	(void) sigprocmask1(l, SIG_SETMASK, mask, 0);
    383 	mutex_exit(p->p_lock);
    384 
    385 	/*
    386 	 * Check for security violations.
    387 	 * Linux doesn't allow any changes to the PSL.
    388 	 */
    389 	if (context.sc_ps != ALPHA_PSL_USERMODE)
    390 	    return(EINVAL);
    391 
    392 	l->l_md.md_tf->tf_regs[FRAME_PC] = context.sc_pc;
    393 	l->l_md.md_tf->tf_regs[FRAME_PS] = context.sc_ps;
    394 
    395 	regtoframe((struct reg *)context.sc_regs, l->l_md.md_tf);
    396 	alpha_pal_wrusp(context.sc_regs[R_SP]);
    397 
    398 	/* Restore fp regs and fpr_cr */
    399 	pcb = lwp_getpcb(l);
    400 	memcpy(&pcb->pcb_fp, (struct fpreg *)context.sc_fpregs,
    401 	    sizeof(struct fpreg));
    402 	/* XXX sc_ownedfp ? */
    403 	/* XXX sc_fp_control ? */
    404 
    405 #ifdef DEBUG
    406 	if (sigdebug & SDB_FOLLOW)
    407 		printf("linux_rt_sigreturn(%d): returns\n", p->p_pid);
    408 #endif
    409 	return (EJUSTRETURN);
    410 }
    411 
    412 int
    413 linux_sys_rt_sigreturn(struct lwp *l, const struct linux_sys_rt_sigreturn_args *uap, register_t *retval)
    414 {
    415 	/* {
    416 		syscallarg(struct linux_rt_sigframe *) sfp;
    417 	} */
    418 	struct linux_rt_sigframe *sfp, sigframe;
    419 	sigset_t mask;
    420 
    421 	/*
    422 	 * The trampoline code hands us the context.
    423 	 * It is unsafe to keep track of it ourselves, in the event that a
    424 	 * program jumps out of a signal handler.
    425 	 */
    426 
    427 	sfp = SCARG(uap, sfp);
    428 
    429 	if (ALIGN(sfp) != (u_int64_t)sfp)
    430 		return(EINVAL);
    431 
    432 	/*
    433 	 * Fetch the frame structure.
    434 	 */
    435 	if (copyin((void *)sfp, &sigframe,
    436 			sizeof(struct linux_rt_sigframe)) != 0)
    437 		return (EFAULT);
    438 
    439 	/* Grab the signal mask */
    440 	linux_to_native_sigset(&mask, &sigframe.uc.uc_sigmask);
    441 
    442 	return(linux_restore_sigcontext(l, sigframe.uc.uc_mcontext, &mask));
    443 }
    444 
    445 
    446 int
    447 linux_sys_sigreturn(struct lwp *l, const struct linux_sys_sigreturn_args *uap, register_t *retval)
    448 {
    449 	/* {
    450 		syscallarg(struct linux_sigframe *) sfp;
    451 	} */
    452 	struct linux_sigframe *sfp, frame;
    453 	sigset_t mask;
    454 
    455 	/*
    456 	 * The trampoline code hands us the context.
    457 	 * It is unsafe to keep track of it ourselves, in the event that a
    458 	 * program jumps out of a signal handler.
    459 	 */
    460 
    461 	sfp = SCARG(uap, sfp);
    462 	if (ALIGN(sfp) != (u_int64_t)sfp)
    463 		return(EINVAL);
    464 
    465 	/*
    466 	 * Fetch the frame structure.
    467 	 */
    468 	if (copyin((void *)sfp, &frame, sizeof(struct linux_sigframe)) != 0)
    469 		return(EFAULT);
    470 
    471 	/* Grab the signal mask. */
    472 	/* XXX use frame.extramask */
    473 	linux_old_to_native_sigset(&mask, frame.sf_sc.sc_mask);
    474 
    475 	return(linux_restore_sigcontext(l, frame.sf_sc, &mask));
    476 }
    477 
    478 /*
    479  * We come here in a last attempt to satisfy a Linux ioctl() call
    480  */
    481 /* XXX XAX update this, add maps, etc... */
    482 int
    483 linux_machdepioctl(struct lwp *l, const struct linux_sys_ioctl_args *uap, register_t *retval)
    484 {
    485 	/* {
    486 		syscallarg(int) fd;
    487 		syscallarg(u_long) com;
    488 		syscallarg(void *) data;
    489 	} */
    490 	struct sys_ioctl_args bia;
    491 	u_long com;
    492 
    493 	SCARG(&bia, fd) = SCARG(uap, fd);
    494 	SCARG(&bia, data) = SCARG(uap, data);
    495 	com = SCARG(uap, com);
    496 
    497 	switch (com) {
    498 	default:
    499 		printf("linux_machdepioctl: invalid ioctl %08lx\n", com);
    500 		return EINVAL;
    501 	}
    502 	SCARG(&bia, com) = com;
    503 	return sys_ioctl(l, &bia, retval);
    504 }
    505 
    506 /* XXX XAX fix this */
    507 dev_t
    508 linux_fakedev(dev_t dev, int raw)
    509 {
    510 	return dev;
    511 }
    512 
    513 int
    514 linux_usertrap(struct lwp *l, vaddr_t trapaddr, void *arg)
    515 {
    516 	return 0;
    517 }
    518