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csan.h revision 1.3.8.2 
      1 /*	$NetBSD: csan.h,v 1.3.8.2 2020/04/13 08:03:30 martin Exp $	*/
      2 
      3 /*
      4  * Copyright (c) 2019 The NetBSD Foundation, Inc.
      5  * All rights reserved.
      6  *
      7  * This code is derived from software contributed to The NetBSD Foundation
      8  * by Maxime Villard.
      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 
     32 #include <sys/ksyms.h>
     33 #include <uvm/uvm.h>
     34 #include <amd64/pmap.h>
     35 #include <x86/cpufunc.h>
     36 
     37 static inline bool
     38 kcsan_md_unsupported(vaddr_t addr)
     39 {
     40 	return (addr >= (vaddr_t)PTE_BASE &&
     41 	    addr < ((vaddr_t)PTE_BASE + NBPD_L4));
     42 }
     43 
     44 static inline bool
     45 kcsan_md_is_avail(void)
     46 {
     47 	return true;
     48 }
     49 
     50 static inline void
     51 kcsan_md_disable_intrs(uint64_t *state)
     52 {
     53 	*state = x86_read_psl();
     54 	x86_disable_intr();
     55 }
     56 
     57 static inline void
     58 kcsan_md_enable_intrs(uint64_t *state)
     59 {
     60 	x86_write_psl(*state);
     61 }
     62 
     63 static inline void
     64 kcsan_md_delay(uint64_t us)
     65 {
     66 	DELAY(us);
     67 }
     68 
     69 static inline bool
     70 __md_unwind_end(const char *name)
     71 {
     72 	if (!strcmp(name, "syscall") ||
     73 	    !strcmp(name, "alltraps") ||
     74 	    !strcmp(name, "handle_syscall") ||
     75 	    !strncmp(name, "Xtrap", 5) ||
     76 	    !strncmp(name, "Xintr", 5) ||
     77 	    !strncmp(name, "Xhandle", 7) ||
     78 	    !strncmp(name, "Xresume", 7) ||
     79 	    !strncmp(name, "Xstray", 6) ||
     80 	    !strncmp(name, "Xhold", 5) ||
     81 	    !strncmp(name, "Xrecurse", 8) ||
     82 	    !strcmp(name, "Xdoreti") ||
     83 	    !strncmp(name, "Xsoft", 5)) {
     84 		return true;
     85 	}
     86 
     87 	return false;
     88 }
     89 
     90 static void
     91 kcsan_md_unwind(void)
     92 {
     93 	uint64_t *rbp, rip;
     94 	const char *mod;
     95 	const char *sym;
     96 	size_t nsym;
     97 	int error;
     98 
     99 	rbp = (uint64_t *)__builtin_frame_address(0);
    100 	nsym = 0;
    101 
    102 	while (1) {
    103 		/* 8(%rbp) contains the saved %rip. */
    104 		rip = *(rbp + 1);
    105 
    106 		if (rip < KERNBASE) {
    107 			break;
    108 		}
    109 		error = ksyms_getname(&mod, &sym, (vaddr_t)rip, KSYMS_PROC);
    110 		if (error) {
    111 			break;
    112 		}
    113 		printf("#%zu %p in %s <%s>\n", nsym, (void *)rip, sym, mod);
    114 		if (__md_unwind_end(sym)) {
    115 			break;
    116 		}
    117 
    118 		rbp = (uint64_t *)*(rbp);
    119 		if (rbp == 0) {
    120 			break;
    121 		}
    122 		nsym++;
    123 
    124 		if (nsym >= 15) {
    125 			break;
    126 		}
    127 	}
    128 }
    129