/*      $NetBSD: linux_trap.c,v 1.12 2021/10/07 12:52:27 msaitoh Exp $  */

/*-
 * Copyright (c) 2001 The NetBSD Foundation, Inc.
 * All rights reserved.
 *
 * This code is derived from software contributed to The NetBSD Foundation
 * by Christos Zoulas.
 *
 * 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 NETBSD FOUNDATION, INC. 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 FOUNDATION 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.
 */

/*
 * x86 Trap and System call handling
 */

#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: linux_trap.c,v 1.12 2021/10/07 12:52:27 msaitoh Exp $");

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/proc.h>
#include <sys/acct.h>
#include <sys/kernel.h>
#include <sys/signal.h>
#include <sys/signalvar.h>
#include <sys/syscall.h>

#include <uvm/uvm_extern.h>

#include <machine/cpu.h>
#include <machine/cpufunc.h>
#include <machine/psl.h>
#include <machine/reg.h>
#include <machine/trap.h>
#include <machine/userret.h>

#include <compat/linux/common/linux_exec.h>

#ifndef DEBUG_LINUX
#define DPRINTF(a)
#else
#define DPRINTF(a)      uprintf a
#endif

struct linux_user_desc {
        unsigned int            entry_number;
        unsigned int            base_addr;
        unsigned int            limit;
        unsigned int            seg_32bit:1;
        unsigned int            contents:2;
        unsigned int            read_exec_only:1;
        unsigned int            limit_in_pages:1;
        unsigned int            seg_not_present:1;
        unsigned int            useable:1;
};

#define LINUX_T_DIVIDE                  0
#define LINUX_T_DEBUG                   1
#define LINUX_T_NMI                     2
#define LINUX_T_INT3                    3
#define LINUX_T_OVERFLOW                4
#define LINUX_T_BOUNDS                  5
#define LINUX_T_INVALID_OP              6
#define LINUX_T_DEVICE_NOT_AVAIL        7
#define LINUX_T_DOUBLE_FAULT            8
#define LINUX_T_COPROC_SEG_OVERRUN      9
#define LINUX_T_INVALID_TSS             10
#define LINUX_T_SEG_NOT_PRESENT         11
#define LINUX_T_STACK_SEG_FAULT         12
#define LINUX_T_GENERAL_PROT_FAULT      13
#define LINUX_T_PAGE_FAULT              14
#define LINUX_T_SPURIOUS_INTERRUPT      15
#define LINUX_T_COPROC_ERROR            16
#define LINUX_T_ALIGN_CHECK             17
#define LINUX_T_MACHINE_CHECK           18      /* XXX */
#define LINUX_T_SIMD_COPROC_ERROR       19      /* XXX */

/* Note 255 is bogus */
static const int trapno_to_x86_vec[] = {
        LINUX_T_INVALID_OP,             /*  0 T_PRIVINFLT */
        LINUX_T_INT3,                   /*  1 T_BPTFLT */
        LINUX_T_COPROC_ERROR,           /*  2 T_ARITHTRAP */
        LINUX_T_SPURIOUS_INTERRUPT,     /*  3 T_ASTFLT XXX: ??? */
        LINUX_T_GENERAL_PROT_FAULT,     /*  4 T_PROTFLT */
        LINUX_T_DEBUG,                  /*  5 T_TRCTRAP */
        LINUX_T_PAGE_FAULT,             /*  6 T_PAGEFLT */
        LINUX_T_ALIGN_CHECK,            /*  7 T_ALIGNFLT */
        LINUX_T_DIVIDE,                 /*  8 T_DIVIDE */
        LINUX_T_NMI,                    /*  9 T_NMI */
        LINUX_T_OVERFLOW,               /* 10 T_OFLOW */
        LINUX_T_BOUNDS,                 /* 11 T_BOUND */
        LINUX_T_DEVICE_NOT_AVAIL,       /* 12 T_DNA */
        LINUX_T_DOUBLE_FAULT,           /* 13 T_DOUBLEFLT */
        LINUX_T_COPROC_SEG_OVERRUN,     /* 14 T_FPOPFLT */
        LINUX_T_INVALID_TSS,            /* 15 T_TSSFLT */
        LINUX_T_SEG_NOT_PRESENT,        /* 16 T_SEGNPFLT */
        LINUX_T_STACK_SEG_FAULT,        /* 17 T_STKFLT */
        LINUX_T_MACHINE_CHECK           /* 18 T_RESERVED XXX: ??? */
};

/* For the nmi and reserved below linux does not post a signal. */
static const int linux_x86_vec_to_sig[] = {
        SIGFPE,                         /*  0 LINUX_T_DIVIDE */
        SIGTRAP,                        /*  1 LINUX_T_DEBUG */
/*nmi*/ SIGSEGV,                        /*  2 LINUX_T_NMI */
        SIGTRAP,                        /*  3 LINUX_T_INT3 */
        SIGSEGV,                        /*  4 LINUX_T_OVERFLOW */
        SIGSEGV,                        /*  5 LINUX_T_BOUNDS */
        SIGILL,                         /*  6 LINUX_T_INVALIDOP */
        SIGSEGV,                        /*  7 LINUX_T_DEVICE_NOT_AVAIL */
        SIGSEGV,                        /*  8 LINUX_T_DOUBLE_FAULT */
        SIGFPE,                         /*  9 LINUX_T_COPROC_SEG_OVERRUN */
        SIGSEGV,                        /* 10 LINUX_T_INVALID_TSS */
        SIGBUS,                         /* 11 LINUX_T_SEG_NOT_PRESENT */
        SIGBUS,                         /* 12 LINUX_T_STACK_SEG_FAULT */
        SIGSEGV,                        /* 13 LINUX_T_GENERAL_PROT_FAULT */
        SIGSEGV,                        /* 14 LINUX_T_PAGE_FAULT */
/*resv*/SIGSEGV,                        /* 15 LINUX_T_SPURIOUS_INTERRUPT */
        SIGFPE,                         /* 16 LINUX_T_COPROC_ERROR */
        SIGSEGV,                        /* 17 LINUX_T_ALIGN_CHECK */
        SIGSEGV                         /* 18 LINUX_T_MACHINE_CHECK */
};

void
linux_trapsignal(struct lwp *l, ksiginfo_t *ksi)
{
        ksiginfo_t nksi;

        switch (ksi->ksi_signo) {
        case SIGILL:
        case SIGTRAP:
        case SIGIOT:
        case SIGBUS:
        case SIGFPE:
        case SIGSEGV:
                KASSERT(KSI_TRAP_P(ksi));
                if (ksi->ksi_trap < __arraycount(trapno_to_x86_vec)) {
                        nksi = *ksi;
                        nksi.ksi_trap = trapno_to_x86_vec[ksi->ksi_trap];
                        if (nksi.ksi_trap < __arraycount(linux_x86_vec_to_sig)) {
                                nksi.ksi_signo
                                    = linux_x86_vec_to_sig[nksi.ksi_trap];
                        } else {
                                uprintf("Unhandled sig type %d\n",
                                    ksi->ksi_trap);
                        }
                        ksi = &nksi;
                } else {
                        uprintf("Unhandled trap type %d\n", ksi->ksi_trap);
                }
                /*FALLTHROUGH*/

        default:
                trapsignal(l, ksi);
                return;
        }
}

int
linux_lwp_setprivate(struct lwp *l, void *ptr)
{
        struct linux_user_desc info;
        int error;

#ifdef __x86_64__
        if ((l->l_proc->p_flag & PK_32) == 0) {
                return lwp_setprivate(l, ptr);
        }
#endif
        error = copyin(ptr, &info, sizeof(info));
        if (error)
                return error;

        DPRINTF(("linux_lwp_setprivate: %i, %x, %x, %i, %i, %i, %i, %i, %i\n",
            info.entry_number, info.base_addr, info.limit, info.seg_32bit,
            info.contents, info.read_exec_only, info.limit_in_pages,
            info.seg_not_present, info.useable));

        if (info.entry_number != GUGS_SEL) {
                info.entry_number = GUGS_SEL;
                error = copyout(&info, ptr, sizeof(info));
                if (error)
                        return error;
        }
        return lwp_setprivate(l, (void *)(uintptr_t)info.base_addr);
}