/*      $OpenBSD: syscall_mi.h,v 1.37 2024/12/27 11:57:16 mpi Exp $     */

/*
 * Copyright (c) 1982, 1986, 1989, 1993
 *      The Regents of the University of California.  All rights reserved.
 *
 * 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.
 * 3. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``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 REGENTS OR CONTRIBUTORS 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.
 *
 *      @(#)kern_xxx.c  8.2 (Berkeley) 11/14/93
 */

#include <sys/param.h>
#include <sys/pledge.h>
#include <sys/acct.h>
#include <sys/tracepoint.h>
#include <sys/syscall.h>
#include <sys/signalvar.h>
#include <uvm/uvm_extern.h>

#ifdef KTRACE
#include <sys/ktrace.h>
#endif

#include "dt.h"
#if NDT > 0
#include <dev/dt/dtvar.h>
#endif

/*
 * Check if a system call is entered from precisely correct location
 */
static inline int
pin_check(struct proc *p, register_t code)
{
        extern char sigcodecall[], sigcoderet[], sigcodecall[];
        struct pinsyscall *pin = NULL, *ppin, *plibcpin;
        struct process *pr = p->p_p;
        vaddr_t addr;
        int error = 0;

        /* point at start of syscall instruction */
        addr = (vaddr_t)PROC_PC(p) - (vaddr_t)(sigcoderet - sigcodecall);
        ppin = &pr->ps_pin;
        plibcpin = &pr->ps_libcpin;

        /*
         * System calls come from the following places, checks are ordered
         * by most common case:
         * 1) dynamic binary: syscalls in libc.so (in the ps_libcpin region)
         * 2a) static binary: syscalls in main program (in the ps_pin region)
         * 2b) dynamic binary: syscalls in ld.so (in the ps_pin region)
         * 3) sigtramp, containing only sigreturn(2)
         */
        if (plibcpin->pn_pins &&
            addr >= plibcpin->pn_start && addr < plibcpin->pn_end)
                pin = plibcpin;
        else if (ppin->pn_pins &&
            addr >= ppin->pn_start && addr < ppin->pn_end)
                pin = ppin;
        else if (PROC_PC(p) == pr->ps_sigcoderet) {
                if (code == SYS_sigreturn)
                        return (0);
                error = EPERM;
                goto die;
        }
        if (pin) {
                if (code >= pin->pn_npins || pin->pn_pins[code] == 0)
                        error = ENOSYS;
                else if (pin->pn_pins[code] + pin->pn_start == addr)
                        ; /* correct location */
                else if (pin->pn_pins[code] == (u_int)-1)
                        ; /* multiple locations, hopefully a boring operation */
                else
                        error = ENOSYS;
        } else
                error = ENOSYS;
        if (error == 0)
                return (0);
die:
#ifdef KTRACE
        if (KTRPOINT(p, KTR_PINSYSCALL))
                ktrpinsyscall(p, error, code, addr);
#endif
        KERNEL_LOCK();
        /* XXX remove or simplify this uprintf() call after OpenBSD 7.5 release */
        uprintf("%s[%d]: pinsyscalls addr %lx code %ld, pinoff 0x%x "
            "(pin%s %d %lx-%lx %lx) (libcpin%s %d %lx-%lx %lx) error %d\n",
            p->p_p->ps_comm, p->p_p->ps_pid, addr, code,
            (pin && code < pin->pn_npins) ? pin->pn_pins[code] : -1,
            pin == ppin ? "(Y)" : "", ppin->pn_npins,
            ppin->pn_start, ppin->pn_end, ppin->pn_end - ppin->pn_start,
            pin == plibcpin ? "(Y)" : "", plibcpin->pn_npins,
            plibcpin->pn_start, plibcpin->pn_end, plibcpin->pn_end - plibcpin->pn_start,
            error);
        p->p_p->ps_acflag |= APINSYS;

        /* Try to stop threads immediately, because this process is suspect */
        if (P_HASSIBLING(p))
                single_thread_set(p, SINGLE_UNWIND | SINGLE_DEEP);
        /* Send uncatchable SIGABRT for coredump */
        sigabort(p);
        KERNEL_UNLOCK();
        return (error);
}

/*
 * The MD setup for a system call has been done; here's the MI part.
 */
static inline int
mi_syscall(struct proc *p, register_t code, const struct sysent *callp,
    register_t *argp, register_t retval[2])
{
        uint64_t tval;
        int lock = !(callp->sy_flags & SY_NOLOCK);
        int error, pledged;

        /* refresh the thread's cache of the process's creds */
        refreshcreds(p);

#ifdef SYSCALL_DEBUG
        KERNEL_LOCK();
        scdebug_call(p, code, argp);
        KERNEL_UNLOCK();
#endif
        TRACEPOINT(raw_syscalls, sys_enter, code, NULL);
#if NDT > 0
        DT_ENTER(syscall, code, callp->sy_argsize, argp);
#endif
#ifdef KTRACE
        if (KTRPOINT(p, KTR_SYSCALL)) {
                /* convert to mask, then include with code */
                ktrsyscall(p, code, callp->sy_argsize, argp);
        }
#endif

        /* SP must be within MAP_STACK space */
        if (!uvm_map_inentry(p, &p->p_spinentry, PROC_STACK(p),
            "[%s]%d/%d sp=%lx inside %lx-%lx: not MAP_STACK\n",
            uvm_map_inentry_sp, p->p_vmspace->vm_map.sserial))
                return (EPERM);

        if ((error = pin_check(p, code)))
                return (error);

        pledged = (p->p_p->ps_flags & PS_PLEDGE);
        if (pledged && (error = pledge_syscall(p, code, &tval))) {
                KERNEL_LOCK();
                error = pledge_fail(p, error, tval);
                KERNEL_UNLOCK();
                return (error);
        }
        if (lock)
                KERNEL_LOCK();
        error = (*callp->sy_call)(p, argp, retval);
        if (lock)
                KERNEL_UNLOCK();

        return (error);
}

/*
 * Finish MI stuff on return, after the registers have been set
 */
static inline void
mi_syscall_return(struct proc *p, register_t code, int error,
    const register_t retval[2])
{
#ifdef SYSCALL_DEBUG
        KERNEL_LOCK();
        scdebug_ret(p, code, error, retval);
        KERNEL_UNLOCK();
#endif
#if NDT > 0
        DT_LEAVE(syscall, code, error, retval[0], retval[1]);
#endif
        TRACEPOINT(raw_syscalls, sys_exit, code, NULL);

        userret(p);

#ifdef KTRACE
        if (KTRPOINT(p, KTR_SYSRET))
                ktrsysret(p, code, error, retval);
#endif
}

/*
 * Finish MI stuff for a new process/thread to return
 */
static inline void
mi_child_return(struct proc *p)
{
#if defined(SYSCALL_DEBUG) || defined(KTRACE) || NDT > 0
        int code = (p->p_flag & P_THREAD) ? SYS___tfork :
            (p->p_p->ps_flags & PS_PPWAIT) ? SYS_vfork : SYS_fork;
        const register_t child_retval[2] = { 0, 1 };
#endif

        TRACEPOINT(sched, on__cpu, NULL);

#ifdef SYSCALL_DEBUG
        KERNEL_LOCK();
        scdebug_ret(p, code, 0, child_retval);
        KERNEL_UNLOCK();
#endif
#if NDT > 0
        DT_LEAVE(syscall, code, 0, child_retval[0], child_retval[1]);
#endif
        TRACEPOINT(raw_syscalls, sys_exit, code, NULL);

        userret(p);

#ifdef KTRACE
        if (KTRPOINT(p, KTR_SYSRET))
                ktrsysret(p, code, 0, child_retval);
#endif
}

/* 
 * Do the specific processing necessary for an AST
 */
static inline void
mi_ast(struct proc *p, int resched)
{
        if (p->p_flag & P_OWEUPC) {
                KERNEL_LOCK();
                ADDUPROF(p);
                KERNEL_UNLOCK();
        }
        if (resched)
                preempt();

        /*
         * XXX could move call to userret() here, but
         * hppa calls ast() in syscall return and sh calls
         * it after userret()
         */
}