/*      $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;
                }
        }
}