/*-
 * Copyright (c) 2018 Olivier Houchard
 * Copyright (c) 2017 Nuxi, https://nuxi.nl/
 *
 * 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 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 AUTHOR 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/param.h>
#include <sys/exec.h>
#include <sys/proc.h>
#include <sys/lock.h>
#include <sys/mutex.h>
#include <sys/syscallsubr.h>
#include <sys/ktr.h>
#include <sys/sysctl.h>
#include <sys/sysent.h>
#include <sys/sysproto.h>
#include <machine/armreg.h>
#include <machine/pcb.h>
#ifdef VFP
#include <machine/vfp.h>
#endif
#include <compat/freebsd32/freebsd32_proto.h>
#include <compat/freebsd32/freebsd32_signal.h>

#include <vm/vm.h>
#include <vm/vm_param.h>
#include <vm/pmap.h>
#include <vm/vm_map.h>

_Static_assert(sizeof(mcontext32_t) == 208, "mcontext32_t size incorrect");
_Static_assert(sizeof(ucontext32_t) == 260, "ucontext32_t size incorrect");
_Static_assert(sizeof(struct __siginfo32) == 64,
    "struct __siginfo32 size incorrect");

extern void freebsd32_sendsig(sig_t catcher, ksiginfo_t *ksi, sigset_t *mask);

SYSCTL_NODE(_compat, OID_AUTO, arm, CTLFLAG_RW | CTLFLAG_MPSAFE, 0,
    "32-bit mode");

/*
 * The first two fields of a ucontext_t are the signal mask and the machine
 * context.  The next field is uc_link; we want to avoid destroying the link
 * when copying out contexts.
 */
#define UC32_COPY_SIZE  offsetof(ucontext32_t, uc_link)

/*
 * Stubs for machine dependent 32-bits system calls.
 */

int
freebsd32_sysarch(struct thread *td, struct freebsd32_sysarch_args *uap)
{
        int error;

#define ARM_SYNC_ICACHE         0
#define ARM_DRAIN_WRITEBUF      1
#define ARM_SET_TP              2
#define ARM_GET_TP              3
#define ARM_GET_VFPSTATE        4

        switch(uap->op) {
        case ARM_SET_TP:
                WRITE_SPECIALREG(tpidr_el0, uap->parms);
                WRITE_SPECIALREG(tpidrro_el0, uap->parms);
                return 0;
        case ARM_SYNC_ICACHE:
                {
                        struct {
                                uint32_t addr;
                                uint32_t size;
                        } args;

                        if ((error = copyin(uap->parms, &args, sizeof(args))) != 0)
                                return (error);
                        if ((uint64_t)args.addr + (uint64_t)args.size > 0xffffffff)
                                return (EINVAL);
                        cpu_icache_sync_range_checked(
                            (void *)(uintptr_t)args.addr, args.size);
                        return 0;
                }
        case ARM_GET_VFPSTATE:
                {
                        mcontext32_vfp_t mcontext_vfp;

                        struct {
                                uint32_t mc_vfp_size;
                                uint32_t mc_vfp;
                        } args;
                        if ((error = copyin(uap->parms, &args, sizeof(args))) != 0)
                                return (error);
                        if (args.mc_vfp_size != sizeof(mcontext_vfp))
                                return (EINVAL);
#ifdef VFP
                        get_fpcontext32(td, &mcontext_vfp);
#else
                        bzero(&mcontext_vfp, sizeof(mcontext_vfp));
#endif
                        error = copyout(&mcontext_vfp,
                                (void *)(uintptr_t)args.mc_vfp,
                                sizeof(mcontext_vfp));
                        return error;
                }
        }

        return (EINVAL);
}

#ifdef VFP
void
get_fpcontext32(struct thread *td, mcontext32_vfp_t *mcp)
{
        struct pcb *pcb;
        int i;

        KASSERT(td == curthread || TD_IS_SUSPENDED(td) ||
            P_SHOULDSTOP(td->td_proc),
            ("not suspended thread %p", td));

        memset(mcp, 0, sizeof(*mcp));
        pcb = td->td_pcb;

        if ((pcb->pcb_fpflags & PCB_FP_STARTED) != 0) {
                /*
                 * If we have just been running VFP instructions we will
                 * need to save the state to memcpy it below.
                 */
                if (td == curthread)
                        vfp_save_state(td, pcb);

                KASSERT(pcb->pcb_fpusaved == &pcb->pcb_fpustate,
                    ("Called get_fpcontext32 while the kernel is using the VFP"));
                KASSERT((pcb->pcb_fpflags & ~PCB_FP_USERMASK) == 0,
                    ("Non-userspace FPU flags set in get_fpcontext32"));
                for (i = 0; i < 16; i++) {
                        uint64_t *tmpreg = (uint64_t *)&pcb->pcb_fpustate.vfp_regs[i];

                        mcp->mcv_reg[i * 2] = tmpreg[0];
                        mcp->mcv_reg[i * 2 + 1] = tmpreg[1];
                }
                mcp->mcv_fpscr = VFP_FPSCR_FROM_SRCR(pcb->pcb_fpustate.vfp_fpcr,
                    pcb->pcb_fpustate.vfp_fpsr);
        }
}

void
set_fpcontext32(struct thread *td, mcontext32_vfp_t *mcp)
{
        struct pcb *pcb;
        int i;

        critical_enter();
        pcb = td->td_pcb;
        if (td == curthread)
                vfp_discard(td);
        for (i = 0; i < 16; i++) {
                uint64_t *tmpreg = (uint64_t *)&pcb->pcb_fpustate.vfp_regs[i];

                tmpreg[0] = mcp->mcv_reg[i * 2];
                tmpreg[1] = mcp->mcv_reg[i * 2 + 1];
        }
        pcb->pcb_fpustate.vfp_fpsr = VFP_FPSR_FROM_FPSCR(mcp->mcv_fpscr);
        pcb->pcb_fpustate.vfp_fpcr = VFP_FPSR_FROM_FPSCR(mcp->mcv_fpscr);
        critical_exit();
}
#endif

static void
get_mcontext32(struct thread *td, mcontext32_t *mcp, int flags)
{
        struct trapframe *tf;
        int i;

        tf = td->td_frame;

        if ((flags & GET_MC_CLEAR_RET) != 0) {
                mcp->mc_gregset[0] = 0;
                mcp->mc_gregset[16] = tf->tf_spsr & ~PSR_C;
        } else {
                mcp->mc_gregset[0] = tf->tf_x[0];
                mcp->mc_gregset[16] = tf->tf_spsr;
        }
        for (i = 1; i < 15; i++)
                mcp->mc_gregset[i] = tf->tf_x[i];
        mcp->mc_gregset[15] = tf->tf_elr;

        mcp->mc_vfp_size = 0;
        mcp->mc_vfp_ptr = 0;

        memset(mcp->mc_spare, 0, sizeof(mcp->mc_spare));
}

static int
set_mcontext32(struct thread *td, mcontext32_t *mcp)
{
        struct trapframe *tf;
        mcontext32_vfp_t mc_vfp;
        uint32_t spsr;
        int i;

        tf = td->td_frame;

        spsr = mcp->mc_gregset[16];
        /*
         * There is no PSR_SS in the 32-bit kernel so ignore it if it's set
         * as we will set it later if needed.
         */
        if ((spsr & ~(PSR_SETTABLE_32 | PSR_SS)) !=
            (tf->tf_spsr & ~(PSR_SETTABLE_32 | PSR_SS)))
                return (EINVAL);

        spsr &= PSR_SETTABLE_32;
        spsr |= tf->tf_spsr & ~PSR_SETTABLE_32;

        if ((td->td_dbgflags & TDB_STEP) != 0) {
                spsr |= PSR_SS;
                td->td_pcb->pcb_flags |= PCB_SINGLE_STEP;
                WRITE_SPECIALREG(mdscr_el1,
                    READ_SPECIALREG(mdscr_el1) | MDSCR_SS);
        }

        for (i = 0; i < 15; i++)
                tf->tf_x[i] = mcp->mc_gregset[i];
        tf->tf_elr = mcp->mc_gregset[15];
        tf->tf_spsr = spsr;
#ifdef VFP
        if (mcp->mc_vfp_size == sizeof(mc_vfp) && mcp->mc_vfp_ptr != 0) {
                if (copyin((void *)(uintptr_t)mcp->mc_vfp_ptr, &mc_vfp,
                                        sizeof(mc_vfp)) != 0)
                        return (EFAULT);
                set_fpcontext32(td, &mc_vfp);
        }
#endif

        return (0);
}

#define UC_COPY_SIZE    offsetof(ucontext32_t, uc_link)

int
freebsd32_getcontext(struct thread *td, struct freebsd32_getcontext_args *uap)
{
        ucontext32_t uc;
        int ret;

        if (uap->ucp == NULL)
                ret = EINVAL;
        else {
                memset(&uc, 0, sizeof(uc));
                get_mcontext32(td, &uc.uc_mcontext, GET_MC_CLEAR_RET);
                PROC_LOCK(td->td_proc);
                uc.uc_sigmask = td->td_sigmask;
                PROC_UNLOCK(td->td_proc);
                ret = copyout(&uc, uap->ucp, UC_COPY_SIZE);
        }
        return (ret);
}

int
freebsd32_setcontext(struct thread *td, struct freebsd32_setcontext_args *uap)
{
        ucontext32_t uc;
        int ret;

        if (uap->ucp == NULL)
                ret = EINVAL;
        else {
                ret = copyin(uap->ucp, &uc, UC_COPY_SIZE);
                if (ret == 0) {
                        ret = set_mcontext32(td, &uc.uc_mcontext);
                        if (ret == 0)
                                kern_sigprocmask(td, SIG_SETMASK, &uc.uc_sigmask,
                                                NULL, 0);
                }
        }
        return (ret);
}

int
freebsd32_sigreturn(struct thread *td, struct freebsd32_sigreturn_args *uap)
{
        ucontext32_t uc;
        int error;

        if (uap == NULL)
                return (EFAULT);
        if (copyin(uap->sigcntxp, &uc, sizeof(uc)))
                return (EFAULT);
        error = set_mcontext32(td, &uc.uc_mcontext);
        if (error != 0)
                return (0);

        /* Restore signal mask. */
        kern_sigprocmask(td, SIG_SETMASK, &uc.uc_sigmask, NULL, 0);

        return (EJUSTRETURN);

}

int
freebsd32_swapcontext(struct thread *td, struct freebsd32_swapcontext_args *uap)
{
        ucontext32_t uc;
        int ret;

        if (uap->oucp == NULL || uap->ucp == NULL)
                ret = EINVAL;
        else {
                bzero(&uc, sizeof(uc));
                get_mcontext32(td, &uc.uc_mcontext, GET_MC_CLEAR_RET);
                PROC_LOCK(td->td_proc);
                uc.uc_sigmask = td->td_sigmask;
                PROC_UNLOCK(td->td_proc);
                ret = copyout(&uc, uap->oucp, UC32_COPY_SIZE);
                if (ret == 0) {
                        ret = copyin(uap->ucp, &uc, UC32_COPY_SIZE);
                        if (ret == 0) {
                                ret = set_mcontext32(td, &uc.uc_mcontext);
                                kern_sigprocmask(td, SIG_SETMASK,
                                                &uc.uc_sigmask, NULL, 0);
                        }
                }
        }
        return (ret);
}

void
freebsd32_sendsig(sig_t catcher, ksiginfo_t *ksi, sigset_t *mask)
{
        struct thread *td;
        struct proc *p;
        struct trapframe *tf;
        struct sigframe32 *fp, frame;
        struct sigacts *psp;
        struct __siginfo32 siginfo;
        struct sysentvec *sysent;
        int onstack;
        int sig;

        siginfo_to_siginfo32(&ksi->ksi_info, &siginfo);
        td = curthread;
        p = td->td_proc;
        PROC_LOCK_ASSERT(p, MA_OWNED);
        sig = ksi->ksi_signo;
        psp = p->p_sigacts;
        mtx_assert(&psp->ps_mtx, MA_OWNED);
        tf = td->td_frame;
        onstack = sigonstack(tf->tf_x[13]);

        CTR4(KTR_SIG, "sendsig: td=%p (%s) catcher=%p sig=%d", td, p->p_comm,
            catcher, sig);

        /* Allocate and validate space for the signal handler context. */
        if ((td->td_pflags & TDP_ALTSTACK) != 0 && !(onstack) &&
            SIGISMEMBER(psp->ps_sigonstack, sig)) {
                fp = (struct sigframe32 *)((uintptr_t)td->td_sigstk.ss_sp +
                    td->td_sigstk.ss_size);
#if defined(COMPAT_43)
                td->td_sigstk.ss_flags |= SS_ONSTACK;
#endif
        } else
                fp = (struct sigframe32 *)td->td_frame->tf_x[13];

        /* make room on the stack */
        fp--;

        /* make the stack aligned */
        fp = (struct sigframe32 *)((unsigned long)(fp) &~ (8 - 1));
        /* Populate the siginfo frame. */
        get_mcontext32(td, &frame.sf_uc.uc_mcontext, 0);
#ifdef VFP
        get_fpcontext32(td, &frame.sf_vfp);
        frame.sf_uc.uc_mcontext.mc_vfp_size = sizeof(fp->sf_vfp);
        frame.sf_uc.uc_mcontext.mc_vfp_ptr = (uint32_t)(uintptr_t)&fp->sf_vfp;
#else
        frame.sf_uc.uc_mcontext.mc_vfp_size = 0;
        frame.sf_uc.uc_mcontext.mc_vfp_ptr = (uint32_t)NULL;
#endif
        frame.sf_si = siginfo;
        frame.sf_uc.uc_sigmask = *mask;
        frame.sf_uc.uc_stack.ss_flags = (td->td_pflags & TDP_ALTSTACK )
            ? ((onstack) ? SS_ONSTACK : 0) : SS_DISABLE;
        frame.sf_uc.uc_stack.ss_sp = (uintptr_t)td->td_sigstk.ss_sp;
        frame.sf_uc.uc_stack.ss_size = td->td_sigstk.ss_size;

        mtx_unlock(&psp->ps_mtx);
        PROC_UNLOCK(td->td_proc);

        /* Copy the sigframe out to the user's stack. */
        if (copyout(&frame, fp, sizeof(*fp)) != 0) {
                /* Process has trashed its stack. Kill it. */
                CTR2(KTR_SIG, "sendsig: sigexit td=%p fp=%p", td, fp);
                PROC_LOCK(p);
                sigexit(td, SIGILL);
        }

        /*
         * Build context to run handler in.  We invoke the handler
         * directly, only returning via the trampoline.  Note the
         * trampoline version numbers are coordinated with machine-
         * dependent code in libc.
         */

        tf->tf_x[0] = sig;
        tf->tf_x[1] = (register_t)&fp->sf_si;
        tf->tf_x[2] = (register_t)&fp->sf_uc;

        /* the trampoline uses r5 as the uc address */
        tf->tf_x[5] = (register_t)&fp->sf_uc;
        tf->tf_elr = (register_t)catcher;
        tf->tf_x[13] = (register_t)fp;
        sysent = p->p_sysent;
        if (PROC_HAS_SHP(p))
                tf->tf_x[14] = (register_t)PROC_SIGCODE(p);
        else
                tf->tf_x[14] = (register_t)(PROC_PS_STRINGS(p) -
                    *(sysent->sv_szsigcode));
        /* Set the mode to enter in the signal handler */
        if ((register_t)catcher & 1)
                tf->tf_spsr |= PSR_T;
        else
                tf->tf_spsr &= ~PSR_T;

        /* Clear the single step flag while in the signal handler */
        if ((td->td_pcb->pcb_flags & PCB_SINGLE_STEP) != 0) {
                td->td_pcb->pcb_flags &= ~PCB_SINGLE_STEP;
                WRITE_SPECIALREG(mdscr_el1,
                    READ_SPECIALREG(mdscr_el1) & ~MDSCR_SS);
                isb();
        }

        CTR3(KTR_SIG, "sendsig: return td=%p pc=%#x sp=%#x", td, tf->tf_x[14],
            tf->tf_x[13]);

        PROC_LOCK(p);
        mtx_lock(&psp->ps_mtx);

}

#ifdef COMPAT_43
/*
 * Mirror the osigreturn definition in kern_sig.c for !i386 platforms. This
 * mirrors what's connected to the FreeBSD/arm syscall.
 */
int
ofreebsd32_sigreturn(struct thread *td, struct ofreebsd32_sigreturn_args *uap)
{

        return (nosys(td, (struct nosys_args *)uap));
}
#endif