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      1 /*	$NetBSD: csan.h,v 1.5 2024/12/04 20:27:39 alnsn Exp $	*/
      2 
      3 /*
      4  * Copyright (c) 2019-2020 Maxime Villard, m00nbsd.net
      5  * All rights reserved.
      6  *
      7  * This code is part of the KCSAN subsystem of the NetBSD kernel.
      8  *
      9  * Redistribution and use in source and binary forms, with or without
     10  * modification, are permitted provided that the following conditions
     11  * are met:
     12  * 1. Redistributions of source code must retain the above copyright
     13  *    notice, this list of conditions and the following disclaimer.
     14  * 2. Redistributions in binary form must reproduce the above copyright
     15  *    notice, this list of conditions and the following disclaimer in the
     16  *    documentation and/or other materials provided with the distribution.
     17  *
     18  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
     19  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
     20  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
     21  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
     22  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
     23  * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
     24  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
     25  * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
     26  * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     27  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     28  * SUCH DAMAGE.
     29  */
     30 
     31 #include <sys/ksyms.h>
     32 #include <uvm/uvm.h>
     33 #include <amd64/pmap.h>
     34 #include <x86/cpufunc.h>
     35 
     36 #include <machine/pmap_private.h>
     37 
     38 static inline bool
     39 kcsan_md_unsupported(vaddr_t addr)
     40 {
     41 	return (addr >= (vaddr_t)PTE_BASE &&
     42 	    addr < ((vaddr_t)PTE_BASE + NBPD_L4));
     43 }
     44 
     45 static inline bool
     46 kcsan_md_is_avail(void)
     47 {
     48 	return true;
     49 }
     50 
     51 static inline void
     52 kcsan_md_disable_intrs(uint64_t *state)
     53 {
     54 	*state = x86_read_psl();
     55 	x86_disable_intr();
     56 }
     57 
     58 static inline void
     59 kcsan_md_enable_intrs(uint64_t *state)
     60 {
     61 	x86_write_psl(*state);
     62 }
     63 
     64 static inline void
     65 kcsan_md_delay(uint64_t us)
     66 {
     67 	DELAY(us);
     68 }
     69 
     70 static inline bool
     71 __md_unwind_end(const char *name)
     72 {
     73 	if (!strcmp(name, "syscall") ||
     74 	    !strcmp(name, "alltraps") ||
     75 	    !strcmp(name, "handle_syscall") ||
     76 	    !strncmp(name, "Xtrap", 5) ||
     77 	    !strncmp(name, "Xintr", 5) ||
     78 	    !strncmp(name, "Xhandle", 7) ||
     79 	    !strncmp(name, "Xresume", 7) ||
     80 	    !strncmp(name, "Xstray", 6) ||
     81 	    !strncmp(name, "Xhold", 5) ||
     82 	    !strncmp(name, "Xrecurse", 8) ||
     83 	    !strcmp(name, "Xdoreti") ||
     84 	    !strncmp(name, "Xsoft", 5)) {
     85 		return true;
     86 	}
     87 
     88 	return false;
     89 }
     90 
     91 static void
     92 kcsan_md_unwind(void)
     93 {
     94 	uint64_t *rbp, rip;
     95 	const char *mod;
     96 	const char *sym;
     97 	size_t nsym;
     98 	int error;
     99 
    100 	rbp = (uint64_t *)__builtin_frame_address(0);
    101 	nsym = 0;
    102 
    103 	while (1) {
    104 		/* 8(%rbp) contains the saved %rip. */
    105 		rip = *(rbp + 1);
    106 
    107 		if (rip < KERNBASE) {
    108 			break;
    109 		}
    110 		error = ksyms_getname(&mod, &sym, (vaddr_t)rip, KSYMS_PROC);
    111 		if (error) {
    112 			break;
    113 		}
    114 		printf("#%zu %p in %s <%s>\n", nsym, (void *)rip, sym, mod);
    115 		if (__md_unwind_end(sym)) {
    116 			break;
    117 		}
    118 
    119 		rbp = (uint64_t *)*(rbp);
    120 		if (rbp == 0) {
    121 			break;
    122 		}
    123 		nsym++;
    124 
    125 		if (nsym >= 15) {
    126 			break;
    127 		}
    128 	}
    129 }
    130