/*      $NetBSD: netbsd32_machdep.c,v 1.5 2020/11/04 07:09:46 skrll Exp $       */

/*-
 * Copyright (c) 2014 The NetBSD Foundation, Inc.
 * All rights reserved.
 *
 * This code is derived from software contributed to The NetBSD Foundation
 * by Matt Thomas of 3am Software Foundry.
 *
 * 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.
 */

#include <sys/cdefs.h>

__RCSID("$NetBSD: netbsd32_machdep.c,v 1.5 2020/11/04 07:09:46 skrll Exp $");

#include <sys/param.h>
#include <sys/ucontext.h>

#include <uvm/uvm_extern.h>

#include <compat/netbsd32/netbsd32.h>
#include <compat/netbsd32/netbsd32_syscallargs.h>

#include <riscv/locore.h>

char machine_arch32[] = MACHINE_ARCH32;
char machine32[] = MACHINE;

void
netbsd32_setregs(struct lwp *l, struct exec_package *pack, vaddr_t stack)
{
        l->l_proc->p_flag |= PK_32;
        setregs(l, pack, stack);
}

/*
 * Start a new LWP
 */
void
startlwp32(void *arg)
{
        ucontext32_t * const uc = arg;
        int error __diagused;

        error = cpu_setmcontext32(curlwp, &uc->uc_mcontext, uc->uc_flags);
        KASSERT(error == 0);

        // Even though this is a ucontext32_t, the space allocated was for a
        // full ucontext_t
        kmem_free(uc, sizeof(ucontext_t));
        userret(curlwp);
}

// We've worked hard to make sure struct reg32 and __gregset32_t are the same.
// Ditto for struct fpreg and fregset_t.

CTASSERT(sizeof(struct reg32) == sizeof(__gregset32_t));
CTASSERT(sizeof(struct fpreg) == sizeof(__fregset_t));

void
cpu_getmcontext32(struct lwp *l, mcontext32_t *mcp, unsigned int *flags)
{
        const struct trapframe * const tf = l->l_md.md_utf;

        /* Save register context. */
        for (size_t i = _X_RA; i <= _X_GP; i++) {
                mcp->__gregs[i] = tf->tf_reg[i];
        }
        mcp->__gregs[_REG_PC] = tf->tf_pc;

        mcp->__private = (intptr_t)l->l_private;

        *flags |= _UC_CPU | _UC_TLSBASE;

        /* Save floating point register context, if any. */
        KASSERT(l == curlwp);
        if (fpu_valid_p(l)) {
                /*
                 * If this process is the current FP owner, dump its
                 * context to the PCB first.
                 */
                fpu_save(l);

                struct pcb * const pcb = lwp_getpcb(l);
                *(struct fpreg *)mcp->__fregs = pcb->pcb_fpregs;
                *flags |= _UC_FPU;
        }
}

int
cpu_mcontext32_validate(struct lwp *l, const mcontext32_t *mcp)
{
        /*
         * Verify that at least the PC and SP are user addresses.
         */
        if ((int32_t) mcp->__gregs[_REG_PC] < 0
            || (int32_t) mcp->__gregs[_REG_SP] < 0
            || (mcp->__gregs[_REG_PC] & 1))
                return EINVAL;

        return 0;
}

int
cpu_setmcontext32(struct lwp *l, const mcontext32_t *mcp, unsigned int flags)
{
        struct trapframe * const tf = l->l_md.md_utf;
        struct proc * const p = l->l_proc;
        const __greg32_t * const gr = mcp->__gregs;
        int error;

        /* Restore register context, if any. */
        if (flags & _UC_CPU) {
                error = cpu_mcontext32_validate(l, mcp);
                if (error)
                        return error;

                /* Save register context. */
                for (size_t i = _X_RA; i <= _X_GP; i++) {
                        tf->tf_reg[i] = (int32_t)gr[i];
                }
                tf->tf_pc = (int32_t) gr[_REG_PC];
        }

        /* Restore the private thread context */
        if (flags & _UC_TLSBASE) {
                lwp_setprivate(l, (void *)(intptr_t)(int32_t)mcp->__private);
        }

        /* Restore floating point register context, if any. */
        if (flags & _UC_FPU) {
                KASSERT(l == curlwp);
                /* Tell PCU we are replacing the FPU contents. */
                fpu_replace(l);

                /*
                 * The PCB FP regs struct includes the FP CSR, so use the
                 * proper size of fpreg when copying.
                 */
                struct pcb * const pcb = lwp_getpcb(l);
                pcb->pcb_fpregs = *(const struct fpreg *)mcp->__fregs;
        }

        mutex_enter(p->p_lock);
        if (flags & _UC_SETSTACK)
                l->l_sigstk.ss_flags |= SS_ONSTACK;
        if (flags & _UC_CLRSTACK)
                l->l_sigstk.ss_flags &= ~SS_ONSTACK;
        mutex_exit(p->p_lock);

        return (0);
}

int
netbsd32_sysarch(struct lwp *l, const struct netbsd32_sysarch_args *uap,
    register_t *retval)
{
        return ENOSYS;
}

vaddr_t
netbsd32_vm_default_addr(struct proc *p, vaddr_t base, vsize_t size,
    int topdown)
{
        if (topdown)
                return VM_DEFAULT_ADDRESS32_TOPDOWN(base, size);
        else
                return VM_DEFAULT_ADDRESS32_BOTTOMUP(base, size);
}