/*      $OpenBSD: sig_machdep.c,v 1.21 2021/10/06 15:46:03 claudio Exp $        */
/*      $NetBSD: sig_machdep.c,v 1.22 2003/10/08 00:28:41 thorpej Exp $ */

/*
 * Copyright (c) 1994-1998 Mark Brinicombe.
 * Copyright (c) 1994 Brini.
 * All rights reserved.
 *
 * This code is derived from software written for Brini by Mark Brinicombe
 *
 * 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. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *      This product includes software developed by Mark Brinicombe
 *      for the NetBSD Project.
 * 4. The name of the company nor the name of the author may be used to
 *    endorse or promote products derived from this software without specific
 *    prior written permission.
 *
 * 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 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.
 *
 * Machine dependant functions for kernel setup
 *
 * Created      : 17/09/94
 */

#include <sys/param.h>

#include <sys/mount.h>          /* XXX only needed by syscallargs.h */
#include <sys/proc.h>
#include <sys/signal.h>
#include <sys/signalvar.h>
#include <sys/syscallargs.h>
#include <sys/systm.h>
#include <sys/user.h>

#include <machine/cpu.h>
#include <machine/frame.h>
#include <machine/pcb.h>

#include <arm/armreg.h>

#include <uvm/uvm_extern.h>

static __inline struct trapframe *
process_frame(struct proc *p)
{
        return p->p_addr->u_pcb.pcb_tf;
}

/*
 * Send an interrupt to process.
 *
 * Stack is set up to allow sigcode to call routine, followed by
 * syscall to sigreturn routine below.  After sigreturn resets the
 * signal mask, the stack, and the frame pointer, it returns to the
 * user specified pc.
 */
int
sendsig(sig_t catcher, int sig, sigset_t mask, const siginfo_t *ksip,
    int info, int onstack)
{
        struct proc *p = curproc;
        struct pcb *pcb = &p->p_addr->u_pcb;
        struct trapframe *tf;
        struct sigframe *fp, frame;

        tf = process_frame(p);

        /* Allocate space for the signal handler context. */
        if ((p->p_sigstk.ss_flags & SS_DISABLE) == 0 &&
            !sigonstack(tf->tf_usr_sp) && onstack)
                fp = (struct sigframe *)
                    trunc_page((vaddr_t)p->p_sigstk.ss_sp + p->p_sigstk.ss_size);
        else
                fp = (struct sigframe *)tf->tf_usr_sp;

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

        /* make the stack aligned */
        fp = (struct sigframe *)STACKALIGN(fp);

        /* Build stack frame for signal trampoline. */
        bzero(&frame, sizeof(frame));
        frame.sf_signum = sig;
        frame.sf_sip = NULL;
        frame.sf_scp = &fp->sf_sc;
        frame.sf_handler = catcher;

        /* Save register context. */
        frame.sf_sc.sc_r0     = tf->tf_r0;
        frame.sf_sc.sc_r1     = tf->tf_r1;
        frame.sf_sc.sc_r2     = tf->tf_r2;
        frame.sf_sc.sc_r3     = tf->tf_r3;
        frame.sf_sc.sc_r4     = tf->tf_r4;
        frame.sf_sc.sc_r5     = tf->tf_r5;
        frame.sf_sc.sc_r6     = tf->tf_r6;
        frame.sf_sc.sc_r7     = tf->tf_r7;
        frame.sf_sc.sc_r8     = tf->tf_r8;
        frame.sf_sc.sc_r9     = tf->tf_r9;
        frame.sf_sc.sc_r10    = tf->tf_r10;
        frame.sf_sc.sc_r11    = tf->tf_r11;
        frame.sf_sc.sc_r12    = tf->tf_r12;
        frame.sf_sc.sc_usr_sp = tf->tf_usr_sp;
        frame.sf_sc.sc_usr_lr = tf->tf_usr_lr;
        frame.sf_sc.sc_svc_lr = tf->tf_svc_lr;
        frame.sf_sc.sc_pc     = tf->tf_pc;
        frame.sf_sc.sc_spsr   = tf->tf_spsr;

        /* Save signal mask. */
        frame.sf_sc.sc_mask = mask;

        /* Save FPU registers. */
        frame.sf_sc.sc_fpused = pcb->pcb_flags & PCB_FPU;
        if (frame.sf_sc.sc_fpused) {
                frame.sf_sc.sc_fpscr = pcb->pcb_fpstate.fp_scr;
                memcpy(&frame.sf_sc.sc_fpreg, &pcb->pcb_fpstate.fp_reg,
                   sizeof(pcb->pcb_fpstate.fp_reg));
                pcb->pcb_flags &= ~PCB_FPU;
                pcb->pcb_fpcpu = NULL;
        }

        if (info) {
                frame.sf_sip = &fp->sf_si;
                frame.sf_si = *ksip;
        }

        frame.sf_sc.sc_cookie = (long)&fp->sf_sc ^ p->p_p->ps_sigcookie;
        if (copyout(&frame, fp, sizeof(frame)) != 0)
                return 1;

        /*
         * Build context to run handler in.  We invoke the handler
         * directly, only returning via the trampoline.
         */
        tf->tf_r0 = sig;
        tf->tf_r1 = (register_t)frame.sf_sip;
        tf->tf_r2 = (register_t)frame.sf_scp;
        tf->tf_pc = (register_t)frame.sf_handler;
        tf->tf_usr_sp = (register_t)fp;

        tf->tf_usr_lr = p->p_p->ps_sigcode;

        return 0;
}

/*
 * System call to cleanup state after a signal
 * has been taken.  Reset signal mask and
 * stack state from context left by sendsig (above).
 * Return to previous pc and psl as specified by
 * context left by sendsig. Check carefully to
 * make sure that the user has not modified the
 * psr to gain improper privileges or to cause
 * a machine fault.
 */

int
sys_sigreturn(struct proc *p, void *v, register_t *retval)
{
        struct sys_sigreturn_args /* {
                syscallarg(struct sigcontext *) sigcntxp;
        } */ *uap = v;
        struct sigcontext ksc, *scp = SCARG(uap, sigcntxp);
        struct pcb *pcb = &p->p_addr->u_pcb;
        struct trapframe *tf;

        if (PROC_PC(p) != p->p_p->ps_sigcoderet) {
                sigexit(p, SIGILL);
                return (EPERM);
        }

        if (copyin(scp, &ksc, sizeof(*scp)) != 0)
                return (EFAULT);

        if (ksc.sc_cookie != ((long)scp ^ p->p_p->ps_sigcookie)) {
                sigexit(p, SIGILL);
                return (EFAULT);
        }

        /* Prevent reuse of the sigcontext cookie */
        ksc.sc_cookie = 0;
        (void)copyout(&ksc.sc_cookie, (caddr_t)scp +
            offsetof(struct sigcontext, sc_cookie), sizeof (ksc.sc_cookie));

        /*
         * Make sure the processor mode has not been tampered with and
         * interrupts have not been disabled.
         */
        if ((ksc.sc_spsr & PSR_MODE) != PSR_USR32_MODE ||
            (ksc.sc_spsr & (PSR_I | PSR_F)) != 0)
                return (EINVAL);

        /* Restore register context. */
        tf = process_frame(p);
        tf->tf_r0    = ksc.sc_r0;
        tf->tf_r1    = ksc.sc_r1;
        tf->tf_r2    = ksc.sc_r2;
        tf->tf_r3    = ksc.sc_r3;
        tf->tf_r4    = ksc.sc_r4;
        tf->tf_r5    = ksc.sc_r5;
        tf->tf_r6    = ksc.sc_r6;
        tf->tf_r7    = ksc.sc_r7;
        tf->tf_r8    = ksc.sc_r8;
        tf->tf_r9    = ksc.sc_r9;
        tf->tf_r10   = ksc.sc_r10;
        tf->tf_r11   = ksc.sc_r11;
        tf->tf_r12   = ksc.sc_r12;
        tf->tf_usr_sp = ksc.sc_usr_sp;
        tf->tf_usr_lr = ksc.sc_usr_lr;
        tf->tf_svc_lr = ksc.sc_svc_lr;
        tf->tf_pc    = ksc.sc_pc;
        tf->tf_spsr  = ksc.sc_spsr;

        /* Restore signal mask. */
        p->p_sigmask = ksc.sc_mask & ~sigcantmask;

        /* Restore FPU registers. */
        if (ksc.sc_fpused) {
                pcb->pcb_fpstate.fp_scr = ksc.sc_fpscr;
                memcpy(&pcb->pcb_fpstate.fp_reg, &ksc.sc_fpreg,
                    sizeof(pcb->pcb_fpstate.fp_reg));
                pcb->pcb_flags |= PCB_FPU;
                pcb->pcb_fpcpu = NULL;
        } else {
                pcb->pcb_flags &= ~PCB_FPU;
                pcb->pcb_fpcpu = NULL;
        }

        return (EJUSTRETURN);
}