/*      $NetBSD: sig_machdep.c,v 1.55 2023/12/20 15:29:06 thorpej Exp $ */

/*
 * Copyright (C) 1995, 1996 Wolfgang Solfrank.
 * Copyright (C) 1995, 1996 TooLs GmbH.
 * 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. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *      This product includes software developed by TooLs GmbH.
 * 4. The name of TooLs GmbH may not be used to endorse or promote products
 *    derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY TOOLS GMBH ``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 TOOLS GMBH 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>
__KERNEL_RCSID(0, "$NetBSD: sig_machdep.c,v 1.55 2023/12/20 15:29:06 thorpej Exp $");

#ifdef _KERNEL_OPT
#include "opt_altivec.h"
#include "opt_ppcarch.h"
#endif

#include <sys/param.h>
#include <sys/mount.h>
#include <sys/proc.h>
#include <sys/syscallargs.h>
#include <sys/systm.h>
#include <sys/ucontext.h>
#include <sys/cpu.h>

#include <uvm/uvm_extern.h>

#include <powerpc/fpu.h>
#include <powerpc/altivec.h>
#include <powerpc/pcb.h>
#include <powerpc/psl.h>

/* Assert that the sizes of these two structures are multiples of 16. */
CTASSERT((sizeof(siginfo_t) & (CALLFRAMELEN-1)) == 0);
CTASSERT((sizeof(ucontext_t) & (CALLFRAMELEN-1)) == 0);

/*
 * Send a signal to process.
 */
void
sendsig_siginfo(const ksiginfo_t *ksi, const sigset_t *mask)
{
        struct lwp * const l = curlwp;
        struct proc * const p = l->l_proc;
        struct trapframe * const tf = l->l_md.md_utf;
        stack_t * const ss = &l->l_sigstk;
        const struct sigact_sigdesc * const sd =
            &p->p_sigacts->sa_sigdesc[ksi->ksi_signo];
        /* save handler before sendsig_reset trashes it! */
        const void * const handler = sd->sd_sigact.sa_handler;
        ucontext_t uc;
        vaddr_t sp, sip, ucp;
        int onstack, error;

        /* Do we need to jump onto the signal stack? */
        onstack = (ss->ss_flags & (SS_DISABLE | SS_ONSTACK)) == 0 &&
            (sd->sd_sigact.sa_flags & SA_ONSTACK) != 0;

        /* Find top of stack.  */
        sp = (onstack ? (vaddr_t)ss->ss_sp + ss->ss_size : tf->tf_fixreg[1]);

        /* Ensure it is aligned. */
        sp &= ~(CALLFRAMELEN-1);

        /* Allocate space for the ucontext.  */
        sp -= sizeof(ucontext_t);

        /* Allocate space for the siginfo.  */
        sp -= sizeof(siginfo_t);

#if 0   /* Not needed; see CTASSERTs above. */
        /* Align it again. */
        sp &= ~(CALLFRAMELEN-1);
#endif

        sip = sp;
        ucp = sp + sizeof(siginfo_t);

        KASSERT((sip & (CALLFRAMELEN-1)) == 0);
        KASSERT((ucp & (CALLFRAMELEN-1)) == 0);

        /*
         * Now allocate space for a call frame, so that there's
         * space for the ABI-mandated stack linkage area in the
         * event the signal handler calls a another function.
         */
        sp -= CALLFRAMELEN;

        /* Save register context. */
        memset(&uc, 0, sizeof(uc));
        uc.uc_flags = _UC_SIGMASK;
        uc.uc_flags |= (ss->ss_flags & SS_ONSTACK) ?
            _UC_SETSTACK : _UC_CLRSTACK;
        uc.uc_sigmask = *mask;
        uc.uc_link = l->l_ctxlink;
        sendsig_reset(l, ksi->ksi_signo);
        mutex_exit(p->p_lock);
        cpu_getmcontext(l, &uc.uc_mcontext, &uc.uc_flags);

        /*
         * Copy the siginfo and ucontext onto the user's stack.
         */
        error = (copyout(&ksi->ksi_info, (void *)sip, sizeof(ksi->ksi_info)) != 0 ||
            copyout(&uc, (void *)ucp, sizeof(uc)) != 0);
        mutex_enter(p->p_lock);

        if (error) {
                /*
                 * Process has trashed its stack; give it an illegal
                 * instruction to halt it in its tracks.
                 */
                sigexit(l, SIGILL);
                /* NOTREACHED */
        }

        /*
         * Build context to run handler in.  Note the trampoline version
         * numbers are coordinated with machine-dependent code in libc.
         */
        switch (sd->sd_vers) {
        case __SIGTRAMP_SIGINFO_VERSION:        /* siginfo sigtramp */
                tf->tf_fixreg[1]  = (register_t)sp;
                tf->tf_fixreg[3]  = (register_t)ksi->ksi_signo;
                tf->tf_fixreg[4]  = (register_t)sip;
                tf->tf_fixreg[5]  = (register_t)ucp;
                /* Preserve ucp across call to signal function */
                tf->tf_fixreg[30] = (register_t)ucp;
                tf->tf_lr         = (register_t)sd->sd_tramp;
                tf->tf_srr0       = (register_t)handler;
                break;

        default:
                goto nosupport;
        }

        /* Remember that we're now on the signal stack. */
        if (onstack)
                ss->ss_flags |= SS_ONSTACK;
        return;

 nosupport:
        /* Don't know what trampoline version; kill it. */
        printf("sendsig_siginfo(sig %d): bad version %d\n",
            ksi->ksi_signo, sd->sd_vers);
        sigexit(l, SIGILL);
        /* NOTREACHED */
}

void
cpu_getmcontext(struct lwp *l, mcontext_t *mcp, unsigned int *flagp)
{
        const struct trapframe * const tf = l->l_md.md_utf;
        __greg_t * const gr = mcp->__gregs;
#if defined(PPC_HAVE_FPU)
        struct pcb * const pcb = lwp_getpcb(l);
#endif

        /* Save GPR context. */
        (void)memcpy(gr, &tf->tf_fixreg, 32 * sizeof (gr[0])); /* GR0-31 */
        gr[_REG_CR]  = tf->tf_cr;
        gr[_REG_LR]  = tf->tf_lr;
        gr[_REG_PC]  = tf->tf_srr0;
        gr[_REG_MSR] = tf->tf_srr1 & PSL_USERSRR1;
#ifdef PPC_HAVE_FPU
        gr[_REG_MSR] |= pcb->pcb_flags & (PCB_FE0|PCB_FE1);
#endif
        gr[_REG_CTR] = tf->tf_ctr;
        gr[_REG_XER] = tf->tf_xer;
#ifdef PPC_OEA
        gr[_REG_MQ]  = tf->tf_mq;
#else
        gr[_REG_MQ]  = 0;
#endif

        *flagp |= _UC_CPU;
        *flagp |= _UC_TLSBASE;

#ifdef PPC_HAVE_FPU
        /* Save FPU context, if any. */
        if (!fpu_save_to_mcontext(l, mcp, flagp))
#endif
                memset(&mcp->__fpregs, 0, sizeof(mcp->__fpregs));

#if defined(ALTIVEC) || defined(PPC_HAVE_SPE)
        /* Save vector context, if any. */
        if (!vec_save_to_mcontext(l, mcp, flagp))
#endif
                memset(&mcp->__vrf, 0, sizeof (mcp->__vrf));
}

int
cpu_mcontext_validate(struct lwp *l, const mcontext_t *mcp)
{
        return 0;
}

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

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

#ifdef PPC_HAVE_FPU
                /*
                 * Always save the FP exception mode in the PCB.
                 */
                struct pcb * const pcb = lwp_getpcb(l);
                pcb->pcb_flags &= ~(PCB_FE0|PCB_FE1);
                pcb->pcb_flags |= gr[_REG_MSR] & (PCB_FE0|PCB_FE1);
#endif

                /*
                 * R2 is the TLS register so avoid updating it here.
                 */

                __greg_t save_r2 = tf->tf_fixreg[_REG_R2];
                (void)memcpy(&tf->tf_fixreg, gr, 32 * sizeof (gr[0]));
                tf->tf_fixreg[_REG_R2] = save_r2;
                tf->tf_cr   = gr[_REG_CR];
                tf->tf_lr   = gr[_REG_LR];
                tf->tf_srr0 = gr[_REG_PC];

                /*
                 * Accept all user-settable bits without complaint;
                 * userland should not need to know the machine-specific
                 * MSR value.
                 */
                tf->tf_srr1 = (gr[_REG_MSR] & PSL_USERMOD) | PSL_USERSET;
                tf->tf_ctr  = gr[_REG_CTR];
                tf->tf_xer  = gr[_REG_XER];
#ifdef PPC_OEA
                tf->tf_mq = gr[_REG_MQ];
#endif
        }

        if (flags & _UC_TLSBASE)
                lwp_setprivate(l, (void *)(uintptr_t)gr[_REG_R2]);

#ifdef PPC_HAVE_FPU
        /* Restore FPU context, if any. */
        if (flags & _UC_FPU)
                fpu_restore_from_mcontext(l, mcp);
#endif

#ifdef ALTIVEC
        /* Restore AltiVec context, if any. */
        if (flags & _UC_POWERPC_VEC)
                vec_restore_from_mcontext(l, mcp);
#endif

#ifdef PPC_HAVE_SPE
        /* Restore SPE context, if any. */
        if (flags & _UC_POWERPC_SPE)
                vec_restore_from_mcontext(l, mcp);
#endif

        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
cpu_lwp_setprivate(lwp_t *l, void *addr)
{
        struct trapframe * const tf = l->l_md.md_utf;

        tf->tf_fixreg[_REG_R2] = (register_t)addr;

        return 0;
}