/*      $NetBSD: csan.h,v 1.5 2024/12/04 20:27:39 alnsn Exp $   */

/*
* Copyright (c) 2019-2020 Maxime Villard, m00nbsd.net
* All rights reserved.
*
* This code is part of the KCSAN subsystem of the NetBSD kernel.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
*    notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
*    notice, this list of conditions and the following disclaimer in the
*    documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/

#include <sys/ksyms.h>
#include <uvm/uvm.h>
#include <amd64/pmap.h>
#include <x86/cpufunc.h>

#include <machine/pmap_private.h>

static inline bool
kcsan_md_unsupported(vaddr_t addr)
{
       return (addr >= (vaddr_t)PTE_BASE &&
           addr < ((vaddr_t)PTE_BASE + NBPD_L4));
}

static inline bool
kcsan_md_is_avail(void)
{
       return true;
}

static inline void
kcsan_md_disable_intrs(uint64_t *state)
{
       *state = x86_read_psl();
       x86_disable_intr();
}

static inline void
kcsan_md_enable_intrs(uint64_t *state)
{
       x86_write_psl(*state);
}

static inline void
kcsan_md_delay(uint64_t us)
{
       DELAY(us);
}

static inline bool
__md_unwind_end(const char *name)
{
       if (!strcmp(name, "syscall") ||
           !strcmp(name, "alltraps") ||
           !strcmp(name, "handle_syscall") ||
           !strncmp(name, "Xtrap", 5) ||
           !strncmp(name, "Xintr", 5) ||
           !strncmp(name, "Xhandle", 7) ||
           !strncmp(name, "Xresume", 7) ||
           !strncmp(name, "Xstray", 6) ||
           !strncmp(name, "Xhold", 5) ||
           !strncmp(name, "Xrecurse", 8) ||
           !strcmp(name, "Xdoreti") ||
           !strncmp(name, "Xsoft", 5)) {
               return true;
       }

       return false;
}

static void
kcsan_md_unwind(void)
{
       uint64_t *rbp, rip;
       const char *mod;
       const char *sym;
       size_t nsym;
       int error;

       rbp = (uint64_t *)__builtin_frame_address(0);
       nsym = 0;

       while (1) {
               /* 8(%rbp) contains the saved %rip. */
               rip = *(rbp + 1);

               if (rip < KERNBASE) {
                       break;
               }
               error = ksyms_getname(&mod, &sym, (vaddr_t)rip, KSYMS_PROC);
               if (error) {
                       break;
               }
               printf("#%zu %p in %s <%s>\n", nsym, (void *)rip, sym, mod);
               if (__md_unwind_end(sym)) {
                       break;
               }

               rbp = (uint64_t *)*(rbp);
               if (rbp == 0) {
                       break;
               }
               nsym++;

               if (nsym >= 15) {
                       break;
               }
       }
}