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      1 /*	$NetBSD: userret.h,v 1.31 2020/07/06 09:34:17 rin Exp $	*/
      2 
      3 /*
      4  * Copyright (C) 1995, 1996 Wolfgang Solfrank.
      5  * Copyright (C) 1995, 1996 TooLs GmbH.
      6  * All rights reserved.
      7  *
      8  * Redistribution and use in source and binary forms, with or without
      9  * modification, are permitted provided that the following conditions
     10  * are met:
     11  * 1. Redistributions of source code must retain the above copyright
     12  *    notice, this list of conditions and the following disclaimer.
     13  * 2. Redistributions in binary form must reproduce the above copyright
     14  *    notice, this list of conditions and the following disclaimer in the
     15  *    documentation and/or other materials provided with the distribution.
     16  * 3. All advertising materials mentioning features or use of this software
     17  *    must display the following acknowledgement:
     18  *	This product includes software developed by TooLs GmbH.
     19  * 4. The name of TooLs GmbH may not be used to endorse or promote products
     20  *    derived from this software without specific prior written permission.
     21  *
     22  * THIS SOFTWARE IS PROVIDED BY TOOLS GMBH ``AS IS'' AND ANY EXPRESS OR
     23  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
     24  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
     25  * IN NO EVENT SHALL TOOLS GMBH BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
     26  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
     27  * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
     28  * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
     29  * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
     30  * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
     31  * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
     32  */
     33 
     34 #ifdef _KERNEL_OPT
     35 #include "opt_altivec.h"
     36 #include "opt_ppcarch.h"
     37 #endif
     38 
     39 #include <sys/userret.h>
     40 #include <sys/ras.h>
     41 
     42 #include <powerpc/fpu.h>
     43 #include <powerpc/psl.h>
     44 
     45 #ifdef PPC_BOOKE
     46 #include <powerpc/spr.h>
     47 #include <powerpc/booke/spr.h>
     48 #endif
     49 
     50 /*
     51  * Define the code needed before returning to user mode, for
     52  * trap and syscall.
     53  */
     54 static __inline void
     55 userret(struct lwp *l, struct trapframe *tf)
     56 {
     57 	KASSERTMSG((tf == trapframe(curlwp)),
     58 	   "tf=%p, trapframe(curlwp)=%p\n", tf, trapframe(curlwp));
     59 
     60 	/* Invoke MI userret code */
     61 	mi_userret(l);
     62 
     63 	KASSERTMSG((tf->tf_srr1 & PSL_PR) != 0,
     64 	    "tf=%p: srr1 (%#lx): PSL_PR isn't set!",
     65 	    tf, tf->tf_srr1);
     66 	KASSERTMSG((tf->tf_srr1 & PSL_FP) == 0
     67 	    || l->l_cpu->ci_data.cpu_pcu_curlwp[PCU_FPU] == l,
     68 	    "tf=%p: srr1 (%#lx): PSL_FP set but FPU curlwp %p is not curlwp %p!",
     69 	    tf, tf->tf_srr1, l->l_cpu->ci_data.cpu_pcu_curlwp[PCU_FPU], l);
     70 
     71 	/* clear SRR1 status bits */
     72 	tf->tf_srr1 &= (PSL_USERSRR1|PSL_FP|PSL_VEC);
     73 
     74 #ifdef ALTIVEC
     75 	/*
     76 	 * We need to manually restore PSL_VEC each time we return
     77 	 * to user mode since PSL_VEC isn't always preserved in SRR1.
     78 	 * We keep a copy of it in md_flags to make restoring easier.
     79 	 */
     80 	tf->tf_srr1 |= l->l_md.md_flags & PSL_VEC;
     81 #endif
     82 #ifdef PPC_BOOKE
     83 	/*
     84 	 * BookE doesn't have PSL_SE but it does have a debug instruction
     85 	 * completion exception but it needs PSL_DE to fire.  Instead we
     86 	 * use IAC1/IAC2 to match the next PC.
     87 	 */
     88 	if (__predict_false(tf->tf_srr1 & PSL_SE)) {
     89 		tf->tf_srr1 &= ~PSL_SE;
     90 		extern void booke_sstep(struct trapframe *); /* ugly */
     91 		booke_sstep(tf);
     92 	}
     93 #endif
     94 
     95 #ifdef __HAVE_RAS
     96 	/*
     97 	 * Check to see if a RAS was interrupted and restart it if it was.
     98 	 */
     99 	struct proc * const p = l->l_proc;
    100 	if (__predict_false(p->p_raslist != NULL)) {
    101 		void * const ras_pc = ras_lookup(p, (void *) tf->tf_srr0);
    102 		if (ras_pc != (void *) -1)
    103 			tf->tf_srr0 = (vaddr_t) ras_pc;
    104 	}
    105 #endif
    106 }
    107