FreeBSD/Linux Kernel Cross Reference
sys/arm/arm/machdep.c

     /*      $NetBSD: arm32_machdep.c,v 1.44 2004/03/24 15:34:47 atatat Exp $        */
     
     /*-
      * SPDX-License-Identifier: BSD-4-Clause
      *
      * Copyright (c) 2004 Olivier Houchard
      * 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 dependent functions for kernel setup
     *
     * Created      : 17/09/94
     * Updated      : 18/04/01 updated for new wscons
     */
    
    #include "opt_ddb.h"
    #include "opt_kstack_pages.h"
    #include "opt_platform.h"
    #include "opt_sched.h"
    #include "opt_timer.h"
    
    #include <sys/cdefs.h>
    __FBSDID("$FreeBSD$");
    
    #include <sys/param.h>
    #include <sys/buf.h>
    #include <sys/bus.h>
    #include <sys/cons.h>
    #include <sys/cpu.h>
    #include <sys/devmap.h>
    #include <sys/efi.h>
    #include <sys/imgact.h>
    #include <sys/kdb.h>
    #include <sys/kernel.h>
    #include <sys/linker.h>
    #include <sys/msgbuf.h>
    #include <sys/physmem.h>
    #include <sys/reboot.h>
    #include <sys/rwlock.h>
    #include <sys/sched.h>
    #include <sys/syscallsubr.h>
    #include <sys/sysent.h>
    #include <sys/sysproto.h>
    #include <sys/vmmeter.h>
    
    #include <vm/vm_object.h>
    #include <vm/vm_page.h>
    #include <vm/vm_pager.h>
    
    #include <machine/asm.h>
    #include <machine/debug_monitor.h>
    #include <machine/machdep.h>
    #include <machine/metadata.h>
    #include <machine/pcb.h>
    #include <machine/platform.h>
    #include <machine/sysarch.h>
    #include <machine/undefined.h>
    #include <machine/vfp.h>
    #include <machine/vmparam.h>
    
    #ifdef FDT
    #include <dev/fdt/fdt_common.h>
    #include <machine/ofw_machdep.h>
    #endif
    
    #ifdef DEBUG
    #define debugf(fmt, args...) printf(fmt, ##args)
    #else
   #define debugf(fmt, args...)
   #endif
   
   #if defined(COMPAT_FREEBSD4) || defined(COMPAT_FREEBSD5) || \
       defined(COMPAT_FREEBSD6) || defined(COMPAT_FREEBSD7) || \
       defined(COMPAT_FREEBSD9)
   #error FreeBSD/arm doesn't provide compatibility with releases prior to 10
   #endif
   
   #if __ARM_ARCH >= 6 && !defined(INTRNG)
   #error armv6 requires INTRNG
   #endif
   
   #ifndef _ARM_ARCH_5E
   #error FreeBSD requires ARMv5 or later
   #endif
   
   struct pcpu __pcpu[MAXCPU];
   struct pcpu *pcpup = &__pcpu[0];
   
   static struct trapframe proc0_tf;
   uint32_t cpu_reset_address = 0;
   int cold = 1;
   vm_offset_t vector_page;
   
   /* The address at which the kernel was loaded.  Set early in initarm(). */
   vm_paddr_t arm_physmem_kernaddr;
   
   int (*_arm_memcpy)(void *, void *, int, int) = NULL;
   int (*_arm_bzero)(void *, int, int) = NULL;
   int _min_memcpy_size = 0;
   int _min_bzero_size = 0;
   
   extern int *end;
   
   #ifdef FDT
   vm_paddr_t pmap_pa;
   #if __ARM_ARCH >= 6
   vm_offset_t systempage;
   vm_offset_t irqstack;
   vm_offset_t undstack;
   vm_offset_t abtstack;
   #else
   /*
    * This is the number of L2 page tables required for covering max
    * (hypothetical) memsize of 4GB and all kernel mappings (vectors, msgbuf,
    * stacks etc.), uprounded to be divisible by 4.
    */
   #define KERNEL_PT_MAX   78
   static struct pv_addr kernel_pt_table[KERNEL_PT_MAX];
   struct pv_addr systempage;
   static struct pv_addr msgbufpv;
   struct pv_addr irqstack;
   struct pv_addr undstack;
   struct pv_addr abtstack;
   static struct pv_addr kernelstack;
   #endif /* __ARM_ARCH >= 6 */
   #endif /* FDT */
   
   #ifdef PLATFORM
   static delay_func *delay_impl;
   static void *delay_arg;
   #endif
   
   struct kva_md_info kmi;
   /*
    * arm32_vector_init:
    *
    *      Initialize the vector page, and select whether or not to
    *      relocate the vectors.
    *
    *      NOTE: We expect the vector page to be mapped at its expected
    *      destination.
    */
   
   extern unsigned int page0[], page0_data[];
   void
   arm_vector_init(vm_offset_t va, int which)
   {
           unsigned int *vectors = (int *) va;
           unsigned int *vectors_data = vectors + (page0_data - page0);
           int vec;
   
           /*
            * Loop through the vectors we're taking over, and copy the
            * vector's insn and data word.
            */
           for (vec = 0; vec < ARM_NVEC; vec++) {
                   if ((which & (1 << vec)) == 0) {
                           /* Don't want to take over this vector. */
                           continue;
                   }
                   vectors[vec] = page0[vec];
                   vectors_data[vec] = page0_data[vec];
           }
   
           /* Now sync the vectors. */
           icache_sync(va, (ARM_NVEC * 2) * sizeof(u_int));
   
           vector_page = va;
   #if __ARM_ARCH < 6
           if (va == ARM_VECTORS_HIGH) {
                   /*
                    * Enable high vectors in the system control reg (SCTLR).
                    *
                    * Assume the MD caller knows what it's doing here, and really
                    * does want the vector page relocated.
                    *
                    * Note: This has to be done here (and not just in
                    * cpu_setup()) because the vector page needs to be
                    * accessible *before* cpu_startup() is called.
                    * Think ddb(9) ...
                    */
                   cpu_control(CPU_CONTROL_VECRELOC, CPU_CONTROL_VECRELOC);
           }
   #endif
   }
   
   static void
   cpu_startup(void *dummy)
   {
           struct pcb *pcb = thread0.td_pcb;
           const unsigned int mbyte = 1024 * 1024;
   #if __ARM_ARCH < 6 && !defined(ARM_CACHE_LOCK_ENABLE)
           vm_page_t m;
   #endif
   
           identify_arm_cpu();
   
           vm_ksubmap_init(&kmi);
   
           /*
            * Display the RAM layout.
            */
           printf("real memory  = %ju (%ju MB)\n",
               (uintmax_t)arm32_ptob(realmem),
               (uintmax_t)arm32_ptob(realmem) / mbyte);
           printf("avail memory = %ju (%ju MB)\n",
               (uintmax_t)arm32_ptob(vm_free_count()),
               (uintmax_t)arm32_ptob(vm_free_count()) / mbyte);
           if (bootverbose) {
                   physmem_print_tables();
                   devmap_print_table();
           }
   
           bufinit();
           vm_pager_bufferinit();
           pcb->pcb_regs.sf_sp = (u_int)thread0.td_kstack +
               USPACE_SVC_STACK_TOP;
           pmap_set_pcb_pagedir(kernel_pmap, pcb);
   #if __ARM_ARCH < 6
           vector_page_setprot(VM_PROT_READ);
           pmap_postinit();
   #ifdef ARM_CACHE_LOCK_ENABLE
           pmap_kenter_user(ARM_TP_ADDRESS, ARM_TP_ADDRESS);
           arm_lock_cache_line(ARM_TP_ADDRESS);
   #else
           m = vm_page_alloc(NULL, 0, VM_ALLOC_NOOBJ | VM_ALLOC_ZERO);
           pmap_kenter_user(ARM_TP_ADDRESS, VM_PAGE_TO_PHYS(m));
   #endif
           *(uint32_t *)ARM_RAS_START = 0;
           *(uint32_t *)ARM_RAS_END = 0xffffffff;
   #endif
   }
   
   SYSINIT(cpu, SI_SUB_CPU, SI_ORDER_FIRST, cpu_startup, NULL);
   
   /*
    * Flush the D-cache for non-DMA I/O so that the I-cache can
    * be made coherent later.
    */
   void
   cpu_flush_dcache(void *ptr, size_t len)
   {
   
           dcache_wb_poc((vm_offset_t)ptr, (vm_paddr_t)vtophys(ptr), len);
   }
   
   /* Get current clock frequency for the given cpu id. */
   int
   cpu_est_clockrate(int cpu_id, uint64_t *rate)
   {
   #if __ARM_ARCH >= 6
           struct pcpu *pc;
   
           pc = pcpu_find(cpu_id);
           if (pc == NULL || rate == NULL)
                   return (EINVAL);
   
           if (pc->pc_clock == 0)
                   return (EOPNOTSUPP);
   
           *rate = pc->pc_clock;
   
           return (0);
   #else
           return (ENXIO);
   #endif
   }
   
   void
   cpu_idle(int busy)
   {
   
           CTR2(KTR_SPARE2, "cpu_idle(%d) at %d", busy, curcpu);
           spinlock_enter();
   #ifndef NO_EVENTTIMERS
           if (!busy)
                   cpu_idleclock();
   #endif
           if (!sched_runnable())
                   cpu_sleep(0);
   #ifndef NO_EVENTTIMERS
           if (!busy)
                   cpu_activeclock();
   #endif
           spinlock_exit();
           CTR2(KTR_SPARE2, "cpu_idle(%d) at %d done", busy, curcpu);
   }
   
   int
   cpu_idle_wakeup(int cpu)
   {
   
           return (0);
   }
   
   #ifdef NO_EVENTTIMERS
   /*
    * Most ARM platforms don't need to do anything special to init their clocks
    * (they get intialized during normal device attachment), and by not defining a
    * cpu_initclocks() function they get this generic one.  Any platform that needs
    * to do something special can just provide their own implementation, which will
    * override this one due to the weak linkage.
    */
   void
   arm_generic_initclocks(void)
   {
   }
   __weak_reference(arm_generic_initclocks, cpu_initclocks);
   
   #else
   void
   cpu_initclocks(void)
   {
   
   #ifdef SMP
           if (PCPU_GET(cpuid) == 0)
                   cpu_initclocks_bsp();
           else
                   cpu_initclocks_ap();
   #else
           cpu_initclocks_bsp();
   #endif
   }
   #endif
   
   #ifdef PLATFORM
   void
   arm_set_delay(delay_func *impl, void *arg)
   {
   
           KASSERT(impl != NULL, ("No DELAY implementation"));
           delay_impl = impl;
           delay_arg = arg;
   }
   
   void
   DELAY(int usec)
   {
   
           TSENTER();
           delay_impl(usec, delay_arg);
           TSEXIT();
   }
   #endif
   
   void
   cpu_pcpu_init(struct pcpu *pcpu, int cpuid, size_t size)
   {
   
   #if __ARM_ARCH >= 6
           pcpu->pc_mpidr = 0xffffffff;
   #endif
   }
   
   void
   spinlock_enter(void)
   {
           struct thread *td;
           register_t cspr;
   
           td = curthread;
           if (td->td_md.md_spinlock_count == 0) {
                   cspr = disable_interrupts(PSR_I | PSR_F);
                   td->td_md.md_spinlock_count = 1;
                   td->td_md.md_saved_cspr = cspr;
           } else
                   td->td_md.md_spinlock_count++;
           critical_enter();
   }
   
   void
   spinlock_exit(void)
   {
           struct thread *td;
           register_t cspr;
   
           td = curthread;
           critical_exit();
           cspr = td->td_md.md_saved_cspr;
           td->td_md.md_spinlock_count--;
           if (td->td_md.md_spinlock_count == 0)
                   restore_interrupts(cspr);
   }
   
   /*
    * Clear registers on exec
    */
   void
   exec_setregs(struct thread *td, struct image_params *imgp, u_long stack)
   {
           struct trapframe *tf = td->td_frame;
   
           memset(tf, 0, sizeof(*tf));
           tf->tf_usr_sp = stack;
           tf->tf_usr_lr = imgp->entry_addr;
           tf->tf_svc_lr = 0x77777777;
           tf->tf_pc = imgp->entry_addr;
           tf->tf_spsr = PSR_USR32_MODE;
           if ((register_t)imgp->entry_addr & 1)
                   tf->tf_spsr |= PSR_T;
   }
   
   
   #ifdef VFP
   /*
    * Get machine VFP context.
    */
   void
   get_vfpcontext(struct thread *td, mcontext_vfp_t *vfp)
   {
           struct pcb *pcb;
   
           pcb = td->td_pcb;
           if (td == curthread) {
                   critical_enter();
                   vfp_store(&pcb->pcb_vfpstate, false);
                   critical_exit();
           } else
                   MPASS(TD_IS_SUSPENDED(td));
           memcpy(vfp->mcv_reg, pcb->pcb_vfpstate.reg,
               sizeof(vfp->mcv_reg));
           vfp->mcv_fpscr = pcb->pcb_vfpstate.fpscr;
   }
   
   /*
    * Set machine VFP context.
    */
   void
   set_vfpcontext(struct thread *td, mcontext_vfp_t *vfp)
   {
           struct pcb *pcb;
   
           pcb = td->td_pcb;
           if (td == curthread) {
                   critical_enter();
                   vfp_discard(td);
                   critical_exit();
           } else
                   MPASS(TD_IS_SUSPENDED(td));
           memcpy(pcb->pcb_vfpstate.reg, vfp->mcv_reg,
               sizeof(pcb->pcb_vfpstate.reg));
           pcb->pcb_vfpstate.fpscr = vfp->mcv_fpscr;
   }
   #endif
   
   int
   arm_get_vfpstate(struct thread *td, void *args)
   {
           int rv;
           struct arm_get_vfpstate_args ua;
           mcontext_vfp_t  mcontext_vfp;
   
           rv = copyin(args, &ua, sizeof(ua));
           if (rv != 0)
                   return (rv);
           if (ua.mc_vfp_size != sizeof(mcontext_vfp_t))
                   return (EINVAL);
   #ifdef VFP
           get_vfpcontext(td, &mcontext_vfp);
   #else
           bzero(&mcontext_vfp, sizeof(mcontext_vfp));
   #endif
   
           rv = copyout(&mcontext_vfp, ua.mc_vfp,  sizeof(mcontext_vfp));
           if (rv != 0)
                   return (rv);
           return (0);
   }
   
   /*
    * Get machine context.
    */
   int
   get_mcontext(struct thread *td, mcontext_t *mcp, int clear_ret)
   {
           struct trapframe *tf = td->td_frame;
           __greg_t *gr = mcp->__gregs;
   
           if (clear_ret & GET_MC_CLEAR_RET) {
                   gr[_REG_R0] = 0;
                   gr[_REG_CPSR] = tf->tf_spsr & ~PSR_C;
           } else {
                   gr[_REG_R0]   = tf->tf_r0;
                   gr[_REG_CPSR] = tf->tf_spsr;
           }
           gr[_REG_R1]   = tf->tf_r1;
           gr[_REG_R2]   = tf->tf_r2;
           gr[_REG_R3]   = tf->tf_r3;
           gr[_REG_R4]   = tf->tf_r4;
           gr[_REG_R5]   = tf->tf_r5;
           gr[_REG_R6]   = tf->tf_r6;
           gr[_REG_R7]   = tf->tf_r7;
           gr[_REG_R8]   = tf->tf_r8;
           gr[_REG_R9]   = tf->tf_r9;
           gr[_REG_R10]  = tf->tf_r10;
           gr[_REG_R11]  = tf->tf_r11;
           gr[_REG_R12]  = tf->tf_r12;
           gr[_REG_SP]   = tf->tf_usr_sp;
           gr[_REG_LR]   = tf->tf_usr_lr;
           gr[_REG_PC]   = tf->tf_pc;
   
           mcp->mc_vfp_size = 0;
           mcp->mc_vfp_ptr = NULL;
           memset(&mcp->mc_spare, 0, sizeof(mcp->mc_spare));
   
           return (0);
   }
   
   /*
    * Set machine context.
    *
    * However, we don't set any but the user modifiable flags, and we won't
    * touch the cs selector.
    */
   int
   set_mcontext(struct thread *td, mcontext_t *mcp)
   {
           mcontext_vfp_t mc_vfp, *vfp;
           struct trapframe *tf = td->td_frame;
           const __greg_t *gr = mcp->__gregs;
           int spsr;
   
           /*
            * Make sure the processor mode has not been tampered with and
            * interrupts have not been disabled.
            */
           spsr = gr[_REG_CPSR];
           if ((spsr & PSR_MODE) != PSR_USR32_MODE ||
               (spsr & (PSR_I | PSR_F)) != 0)
                   return (EINVAL);
   
   #ifdef WITNESS
           if (mcp->mc_vfp_size != 0 && mcp->mc_vfp_size != sizeof(mc_vfp)) {
                   printf("%s: %s: Malformed mc_vfp_size: %d (0x%08X)\n",
                       td->td_proc->p_comm, __func__,
                       mcp->mc_vfp_size, mcp->mc_vfp_size);
           } else if (mcp->mc_vfp_size != 0 && mcp->mc_vfp_ptr == NULL) {
                   printf("%s: %s: c_vfp_size != 0 but mc_vfp_ptr == NULL\n",
                       td->td_proc->p_comm, __func__);
           }
   #endif
   
           if (mcp->mc_vfp_size == sizeof(mc_vfp) && mcp->mc_vfp_ptr != NULL) {
                   if (copyin(mcp->mc_vfp_ptr, &mc_vfp, sizeof(mc_vfp)) != 0)
                           return (EFAULT);
                   vfp = &mc_vfp;
           } else {
                   vfp = NULL;
           }
   
           tf->tf_r0 = gr[_REG_R0];
           tf->tf_r1 = gr[_REG_R1];
           tf->tf_r2 = gr[_REG_R2];
           tf->tf_r3 = gr[_REG_R3];
           tf->tf_r4 = gr[_REG_R4];
           tf->tf_r5 = gr[_REG_R5];
           tf->tf_r6 = gr[_REG_R6];
           tf->tf_r7 = gr[_REG_R7];
           tf->tf_r8 = gr[_REG_R8];
           tf->tf_r9 = gr[_REG_R9];
           tf->tf_r10 = gr[_REG_R10];
           tf->tf_r11 = gr[_REG_R11];
           tf->tf_r12 = gr[_REG_R12];
           tf->tf_usr_sp = gr[_REG_SP];
           tf->tf_usr_lr = gr[_REG_LR];
           tf->tf_pc = gr[_REG_PC];
           tf->tf_spsr = gr[_REG_CPSR];
   #ifdef VFP
           if (vfp != NULL)
                   set_vfpcontext(td, vfp);
   #endif
           return (0);
   }
   
   void
   sendsig(catcher, ksi, mask)
           sig_t catcher;
           ksiginfo_t *ksi;
           sigset_t *mask;
   {
           struct thread *td;
           struct proc *p;
           struct trapframe *tf;
           struct sigframe *fp, frame;
           struct sigacts *psp;
           struct sysentvec *sysent;
           int onstack;
           int sig;
           int code;
   
           td = curthread;
           p = td->td_proc;
           PROC_LOCK_ASSERT(p, MA_OWNED);
           sig = ksi->ksi_signo;
           code = ksi->ksi_code;
           psp = p->p_sigacts;
           mtx_assert(&psp->ps_mtx, MA_OWNED);
           tf = td->td_frame;
           onstack = sigonstack(tf->tf_usr_sp);
   
           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 sigframe *)((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 sigframe *)td->td_frame->tf_usr_sp;
   
           /* make room on the stack */
           fp--;
   
           /* make the stack aligned */
           fp = (struct sigframe *)STACKALIGN(fp);
           /* Populate the siginfo frame. */
           bzero(&frame, sizeof(frame));
           get_mcontext(td, &frame.sf_uc.uc_mcontext, 0);
   #ifdef VFP
           get_vfpcontext(td, &frame.sf_vfp);
           frame.sf_uc.uc_mcontext.mc_vfp_size = sizeof(fp->sf_vfp);
           frame.sf_uc.uc_mcontext.mc_vfp_ptr = &fp->sf_vfp;
   #else
           frame.sf_uc.uc_mcontext.mc_vfp_size = 0;
           frame.sf_uc.uc_mcontext.mc_vfp_ptr = NULL;
   #endif
           frame.sf_si = ksi->ksi_info;
           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 = td->td_sigstk;
           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_r0 = sig;
           tf->tf_r1 = (register_t)&fp->sf_si;
           tf->tf_r2 = (register_t)&fp->sf_uc;
   
           /* the trampoline uses r5 as the uc address */
           tf->tf_r5 = (register_t)&fp->sf_uc;
           tf->tf_pc = (register_t)catcher;
           tf->tf_usr_sp = (register_t)fp;
           sysent = p->p_sysent;
           if (sysent->sv_sigcode_base != 0)
                   tf->tf_usr_lr = (register_t)sysent->sv_sigcode_base;
           else
                   tf->tf_usr_lr = (register_t)(sysent->sv_psstrings -
                       *(sysent->sv_szsigcode));
           /* Set the mode to enter in the signal handler */
   #if __ARM_ARCH >= 7
           if ((register_t)catcher & 1)
                   tf->tf_spsr |= PSR_T;
           else
                   tf->tf_spsr &= ~PSR_T;
   #endif
   
           CTR3(KTR_SIG, "sendsig: return td=%p pc=%#x sp=%#x", td, tf->tf_usr_lr,
               tf->tf_usr_sp);
   
           PROC_LOCK(p);
           mtx_lock(&psp->ps_mtx);
   }
   
   int
   sys_sigreturn(td, uap)
           struct thread *td;
           struct sigreturn_args /* {
                   const struct __ucontext *sigcntxp;
           } */ *uap;
   {
           ucontext_t uc;
           int error;
   
           if (uap == NULL)
                   return (EFAULT);
           if (copyin(uap->sigcntxp, &uc, sizeof(uc)))
                   return (EFAULT);
           /* Restore register context. */
           error = set_mcontext(td, &uc.uc_mcontext);
           if (error != 0)
                   return (error);
   
           /* Restore signal mask. */
           kern_sigprocmask(td, SIG_SETMASK, &uc.uc_sigmask, NULL, 0);
   
           return (EJUSTRETURN);
   }
   
   /*
    * Construct a PCB from a trapframe. This is called from kdb_trap() where
    * we want to start a backtrace from the function that caused us to enter
    * the debugger. We have the context in the trapframe, but base the trace
    * on the PCB. The PCB doesn't have to be perfect, as long as it contains
    * enough for a backtrace.
    */
   void
   makectx(struct trapframe *tf, struct pcb *pcb)
   {
           pcb->pcb_regs.sf_r4 = tf->tf_r4;
           pcb->pcb_regs.sf_r5 = tf->tf_r5;
           pcb->pcb_regs.sf_r6 = tf->tf_r6;
           pcb->pcb_regs.sf_r7 = tf->tf_r7;
           pcb->pcb_regs.sf_r8 = tf->tf_r8;
           pcb->pcb_regs.sf_r9 = tf->tf_r9;
           pcb->pcb_regs.sf_r10 = tf->tf_r10;
           pcb->pcb_regs.sf_r11 = tf->tf_r11;
           pcb->pcb_regs.sf_r12 = tf->tf_r12;
           pcb->pcb_regs.sf_pc = tf->tf_pc;
           pcb->pcb_regs.sf_lr = tf->tf_usr_lr;
           pcb->pcb_regs.sf_sp = tf->tf_usr_sp;
   }
   
   void
   pcpu0_init(void)
   {
   #if __ARM_ARCH >= 6
           set_curthread(&thread0);
   #endif
           pcpu_init(pcpup, 0, sizeof(struct pcpu));
   #if __ARM_ARCH >= 6
           pcpup->pc_mpidr = cp15_mpidr_get() & 0xFFFFFF;
   #endif
           PCPU_SET(curthread, &thread0);
   }
   
   /*
    * Initialize proc0
    */
   void
   init_proc0(vm_offset_t kstack)
   {
           proc_linkup0(&proc0, &thread0);
           thread0.td_kstack = kstack;
           thread0.td_kstack_pages = kstack_pages;
           thread0.td_pcb = (struct pcb *)(thread0.td_kstack +
               thread0.td_kstack_pages * PAGE_SIZE) - 1;
           thread0.td_pcb->pcb_flags = 0;
           thread0.td_pcb->pcb_vfpcpu = -1;
           thread0.td_pcb->pcb_vfpstate.fpscr = VFPSCR_DN;
           thread0.td_frame = &proc0_tf;
           pcpup->pc_curpcb = thread0.td_pcb;
   }
   
   #if __ARM_ARCH >= 6
   void
   set_stackptrs(int cpu)
   {
   
           set_stackptr(PSR_IRQ32_MODE,
               irqstack + ((IRQ_STACK_SIZE * PAGE_SIZE) * (cpu + 1)));
           set_stackptr(PSR_ABT32_MODE,
               abtstack + ((ABT_STACK_SIZE * PAGE_SIZE) * (cpu + 1)));
           set_stackptr(PSR_UND32_MODE,
               undstack + ((UND_STACK_SIZE * PAGE_SIZE) * (cpu + 1)));
   }
   #else
   void
   set_stackptrs(int cpu)
   {
   
           set_stackptr(PSR_IRQ32_MODE,
               irqstack.pv_va + ((IRQ_STACK_SIZE * PAGE_SIZE) * (cpu + 1)));
           set_stackptr(PSR_ABT32_MODE,
               abtstack.pv_va + ((ABT_STACK_SIZE * PAGE_SIZE) * (cpu + 1)));
           set_stackptr(PSR_UND32_MODE,
               undstack.pv_va + ((UND_STACK_SIZE * PAGE_SIZE) * (cpu + 1)));
   }
   #endif
   
   static void
   arm_kdb_init(void)
   {
   
           kdb_init();
   #ifdef KDB
           if (boothowto & RB_KDB)
                   kdb_enter(KDB_WHY_BOOTFLAGS, "Boot flags requested debugger");
   #endif
   }
   
   #ifdef FDT
   #if __ARM_ARCH < 6
   void *
   initarm(struct arm_boot_params *abp)
   {
           struct mem_region mem_regions[FDT_MEM_REGIONS];
           struct pv_addr kernel_l1pt;
           struct pv_addr dpcpu;
           vm_offset_t dtbp, freemempos, l2_start, lastaddr;
           uint64_t memsize;
           uint32_t l2size;
           char *env;
           void *kmdp;
           u_int l1pagetable;
           int i, j, err_devmap, mem_regions_sz;
   
           lastaddr = parse_boot_param(abp);
           arm_physmem_kernaddr = abp->abp_physaddr;
   
           memsize = 0;
   
           cpuinfo_init();
           set_cpufuncs();
   
           /*
            * Find the dtb passed in by the boot loader.
            */
           kmdp = preload_search_by_type("elf kernel");
           if (kmdp != NULL)
                   dtbp = MD_FETCH(kmdp, MODINFOMD_DTBP, vm_offset_t);
           else
                   dtbp = (vm_offset_t)NULL;
   
   #if defined(FDT_DTB_STATIC)
           /*
            * In case the device tree blob was not retrieved (from metadata) try
            * to use the statically embedded one.
            */
           if (dtbp == (vm_offset_t)NULL)
                   dtbp = (vm_offset_t)&fdt_static_dtb;
   #endif
   
           if (OF_install(OFW_FDT, 0) == FALSE)
                   panic("Cannot install FDT");
   
           if (OF_init((void *)dtbp) != 0)
                   panic("OF_init failed with the found device tree");
   
           /* Grab physical memory regions information from device tree. */
           if (fdt_get_mem_regions(mem_regions, &mem_regions_sz, &memsize) != 0)
                   panic("Cannot get physical memory regions");
           physmem_hardware_regions(mem_regions, mem_regions_sz);
   
           /* Grab reserved memory regions information from device tree. */
           if (fdt_get_reserved_regions(mem_regions, &mem_regions_sz) == 0)
                   physmem_exclude_regions(mem_regions, mem_regions_sz,
                       EXFLAG_NODUMP | EXFLAG_NOALLOC);
   
           /* Platform-specific initialisation */
           platform_probe_and_attach();
   
           pcpu0_init();
   
           /* Do basic tuning, hz etc */
           init_param1();
   
           /* Calculate number of L2 tables needed for mapping vm_page_array */
           l2size = (memsize / PAGE_SIZE) * sizeof(struct vm_page);
           l2size = (l2size >> L1_S_SHIFT) + 1;
   
           /*
            * Add one table for end of kernel map, one for stacks, msgbuf and
            * L1 and L2 tables map,  one for vectors map and two for
            * l2 structures from pmap_bootstrap.
            */
           l2size += 5;
   
           /* Make it divisible by 4 */
           l2size = (l2size + 3) & ~3;
   
           freemempos = (lastaddr + PAGE_MASK) & ~PAGE_MASK;
   
           /* Define a macro to simplify memory allocation */
   #define valloc_pages(var, np)                                           \
           alloc_pages((var).pv_va, (np));                                 \
           (var).pv_pa = (var).pv_va + (abp->abp_physaddr - KERNVIRTADDR);
   
   #define alloc_pages(var, np)                                            \
           (var) = freemempos;                                             \
           freemempos += (np * PAGE_SIZE);                                 \
           memset((char *)(var), 0, ((np) * PAGE_SIZE));
   
           while (((freemempos - L1_TABLE_SIZE) & (L1_TABLE_SIZE - 1)) != 0)
                   freemempos += PAGE_SIZE;
           valloc_pages(kernel_l1pt, L1_TABLE_SIZE / PAGE_SIZE);
   
           for (i = 0, j = 0; i < l2size; ++i) {
                   if (!(i % (PAGE_SIZE / L2_TABLE_SIZE_REAL))) {
                           valloc_pages(kernel_pt_table[i],
                               L2_TABLE_SIZE / PAGE_SIZE);
                           j = i;
                   } else {
                           kernel_pt_table[i].pv_va = kernel_pt_table[j].pv_va +
                               L2_TABLE_SIZE_REAL * (i - j);
                           kernel_pt_table[i].pv_pa =
                               kernel_pt_table[i].pv_va - KERNVIRTADDR +
                               abp->abp_physaddr;
   
                   }
           }
           /*
            * Allocate a page for the system page mapped to 0x00000000
            * or 0xffff0000. This page will just contain the system vectors
            * and can be shared by all processes.
            */
           valloc_pages(systempage, 1);
   
           /* Allocate dynamic per-cpu area. */
           valloc_pages(dpcpu, DPCPU_SIZE / PAGE_SIZE);
           dpcpu_init((void *)dpcpu.pv_va, 0);
   
           /* Allocate stacks for all modes */
           valloc_pages(irqstack, IRQ_STACK_SIZE * MAXCPU);
           valloc_pages(abtstack, ABT_STACK_SIZE * MAXCPU);
           valloc_pages(undstack, UND_STACK_SIZE * MAXCPU);
           valloc_pages(kernelstack, kstack_pages);
           valloc_pages(msgbufpv, round_page(msgbufsize) / PAGE_SIZE);
   
           /*
            * Now we start construction of the L1 page table
            * We start by mapping the L2 page tables into the L1.
            * This means that we can replace L1 mappings later on if necessary
            */
           l1pagetable = kernel_l1pt.pv_va;
   
           /*
            * Try to map as much as possible of kernel text and data using
            * 1MB section mapping and for the rest of initial kernel address
            * space use L2 coarse tables.
            *
            * Link L2 tables for mapping remainder of kernel (modulo 1MB)
            * and kernel structures
            */
           l2_start = lastaddr & ~(L1_S_OFFSET);
           for (i = 0 ; i < l2size - 1; i++)
                   pmap_link_l2pt(l1pagetable, l2_start + i * L1_S_SIZE,
                       &kernel_pt_table[i]);
   
           pmap_curmaxkvaddr = l2_start + (l2size - 1) * L1_S_SIZE;
   
           /* Map kernel code and data */
           pmap_map_chunk(l1pagetable, KERNVIRTADDR, abp->abp_physaddr,
              (((uint32_t)(lastaddr) - KERNVIRTADDR) + PAGE_MASK) & ~PAGE_MASK,
               VM_PROT_READ|VM_PROT_WRITE, PTE_CACHE);
   
           /* Map L1 directory and allocated L2 page tables */
           pmap_map_chunk(l1pagetable, kernel_l1pt.pv_va, kernel_l1pt.pv_pa,
               L1_TABLE_SIZE, VM_PROT_READ|VM_PROT_WRITE, PTE_PAGETABLE);
   
           pmap_map_chunk(l1pagetable, kernel_pt_table[0].pv_va,
               kernel_pt_table[0].pv_pa,
               L2_TABLE_SIZE_REAL * l2size,
               VM_PROT_READ|VM_PROT_WRITE, PTE_PAGETABLE);
   
           /* Map allocated DPCPU, stacks and msgbuf */
           pmap_map_chunk(l1pagetable, dpcpu.pv_va, dpcpu.pv_pa,
               freemempos - dpcpu.pv_va,
               VM_PROT_READ|VM_PROT_WRITE, PTE_CACHE);
   
          /* Link and map the vector page */
          pmap_link_l2pt(l1pagetable, ARM_VECTORS_HIGH,
              &kernel_pt_table[l2size - 1]);
          pmap_map_entry(l1pagetable, ARM_VECTORS_HIGH, systempage.pv_pa,
              VM_PROT_READ|VM_PROT_WRITE|VM_PROT_EXECUTE, PTE_CACHE);
  
          /* Establish static device mappings. */
          err_devmap = platform_devmap_init();
          devmap_bootstrap(l1pagetable, NULL);
          vm_max_kernel_address = platform_lastaddr();
  
          cpu_domains((DOMAIN_CLIENT << (PMAP_DOMAIN_KERNEL * 2)) | DOMAIN_CLIENT);
          pmap_pa = kernel_l1pt.pv_pa;
          cpu_setttb(kernel_l1pt.pv_pa);
          cpu_tlb_flushID();
          cpu_domains(DOMAIN_CLIENT << (PMAP_DOMAIN_KERNEL * 2));
  
          /*
           * Now that proper page tables are installed, call cpu_setup() to enable
           * instruction and data caches and other chip-specific features.
           */
          cpu_setup();
  
          /*
           * Only after the SOC registers block is mapped we can perform device
           * tree fixups, as they may attempt to read parameters from hardware.
           */
          OF_interpret("perform-fixup", 0);
  
          platform_gpio_init();
  
          cninit();
  
          debugf("initarm: console initialized\n");
          debugf(" arg1 kmdp = 0x%08x\n", (uint32_t)kmdp);
          debugf(" boothowto = 0x%08x\n", boothowto);
          debugf(" dtbp = 0x%08x\n", (uint32_t)dtbp);
          arm_print_kenv();
  
          env = kern_getenv("kernelname");
          if (env != NULL) {
                  strlcpy(kernelname, env, sizeof(kernelname));
                  freeenv(env);
          }
  
          if (err_devmap != 0)
                  printf("WARNING: could not fully configure devmap, error=%d\n",
                      err_devmap);
  
          platform_late_init();
  
          /*
           * Pages were allocated during the secondary bootstrap for the
           * stacks for different CPU modes.
           * We must now set the r13 registers in the different CPU modes to
           * point to these stacks.
           * Since the ARM stacks use STMFD etc. we must set r13 to the top end
           * of the stack memory.
           */
          cpu_control(CPU_CONTROL_MMU_ENABLE, CPU_CONTROL_MMU_ENABLE);
  
          set_stackptrs(0);
  
          /*
           * We must now clean the cache again....
           * Cleaning may be done by reading new data to displace any
           * dirty data in the cache. This will have happened in cpu_setttb()
           * but since we are boot strapping the addresses used for the read
           * may have just been remapped and thus the cache could be out
           * of sync. A re-clean after the switch will cure this.
           * After booting there are no gross relocations of the kernel thus
           * this problem will not occur after initarm().
           */
          cpu_idcache_wbinv_all();
  
          undefined_init();
  
          init_proc0(kernelstack.pv_va);
  
          arm_vector_init(ARM_VECTORS_HIGH, ARM_VEC_ALL);
          pmap_bootstrap(freemempos, &kernel_l1pt);
          msgbufp = (void *)msgbufpv.pv_va;
          msgbufinit(msgbufp, msgbufsize);
          mutex_init();
  
          /*
           * Exclude the kernel (and all the things we allocated which immediately
           * follow the kernel) from the VM allocation pool but not from crash
           * dumps.  virtual_avail is a global variable which tracks the kva we've
           * "allocated" while setting up pmaps.
           *
           * Prepare the list of physical memory available to the vm subsystem.
           */
          physmem_exclude_region(abp->abp_physaddr,
              (virtual_avail - KERNVIRTADDR), EXFLAG_NOALLOC);
          physmem_init_kernel_globals();
  
          init_param2(physmem);
          dbg_monitor_init();
          arm_kdb_init();
  
          return ((void *)(kernelstack.pv_va + USPACE_SVC_STACK_TOP -
              sizeof(struct pcb)));
  }
  #else /* __ARM_ARCH < 6 */
  void *
  initarm(struct arm_boot_params *abp)
  {
          struct mem_region mem_regions[FDT_MEM_REGIONS];
          vm_paddr_t lastaddr;
          vm_offset_t dtbp, kernelstack, dpcpu;
          char *env;
          void *kmdp;
          int err_devmap, mem_regions_sz;
  #ifdef EFI
          struct efi_map_header *efihdr;
  #endif
  
          /* get last allocated physical address */
          arm_physmem_kernaddr = abp->abp_physaddr;
          lastaddr = parse_boot_param(abp) - KERNVIRTADDR + arm_physmem_kernaddr;
  
          set_cpufuncs();
          cpuinfo_init();
  
          /*
           * Find the dtb passed in by the boot loader.
           */
          kmdp = preload_search_by_type("elf kernel");
          dtbp = MD_FETCH(kmdp, MODINFOMD_DTBP, vm_offset_t);
  #if defined(FDT_DTB_STATIC)
          /*
           * In case the device tree blob was not retrieved (from metadata) try
           * to use the statically embedded one.
           */
          if (dtbp == (vm_offset_t)NULL)
                  dtbp = (vm_offset_t)&fdt_static_dtb;
  #endif
  
          if (OF_install(OFW_FDT, 0) == FALSE)
                  panic("Cannot install FDT");
  
          if (OF_init((void *)dtbp) != 0)
                  panic("OF_init failed with the found device tree");
  
  #if defined(LINUX_BOOT_ABI)
          arm_parse_fdt_bootargs();
  #endif
  
  #ifdef EFI
          efihdr = (struct efi_map_header *)preload_search_info(kmdp,
              MODINFO_METADATA | MODINFOMD_EFI_MAP);
          if (efihdr != NULL) {
                  arm_add_efi_map_entries(efihdr, mem_regions, &mem_regions_sz);
          } else
  #endif
          {
                  /* Grab physical memory regions information from device tree. */
                  if (fdt_get_mem_regions(mem_regions, &mem_regions_sz,NULL) != 0)
                          panic("Cannot get physical memory regions");
          }
          physmem_hardware_regions(mem_regions, mem_regions_sz);
  
          /* Grab reserved memory regions information from device tree. */
          if (fdt_get_reserved_regions(mem_regions, &mem_regions_sz) == 0)
                  physmem_exclude_regions(mem_regions, mem_regions_sz,
                      EXFLAG_NODUMP | EXFLAG_NOALLOC);
  
          /*
           * Set TEX remapping registers.
           * Setup kernel page tables and switch to kernel L1 page table.
           */
          pmap_set_tex();
          pmap_bootstrap_prepare(lastaddr);
  
          /*
           * If EARLY_PRINTF support is enabled, we need to re-establish the
           * mapping after pmap_bootstrap_prepare() switches to new page tables.
           * Note that we can only do the remapping if the VA is outside the
           * kernel, now that we have real virtual (not VA=PA) mappings in effect.
           * Early printf does not work between the time pmap_set_tex() does
           * cp15_prrr_set() and this code remaps the VA.
           */
  #if defined(EARLY_PRINTF) && defined(SOCDEV_PA) && defined(SOCDEV_VA) && SOCDEV_VA < KERNBASE
          pmap_preboot_map_attr(SOCDEV_PA, SOCDEV_VA, 1024 * 1024, 
              VM_PROT_READ | VM_PROT_WRITE, VM_MEMATTR_DEVICE);
  #endif
  
          /*
           * Now that proper page tables are installed, call cpu_setup() to enable
           * instruction and data caches and other chip-specific features.
           */
          cpu_setup();
  
          /* Platform-specific initialisation */
          platform_probe_and_attach();
          pcpu0_init();
  
          /* Do basic tuning, hz etc */
          init_param1();
  
          /*
           * Allocate a page for the system page mapped to 0xffff0000
           * This page will just contain the system vectors and can be
           * shared by all processes.
           */
          systempage = pmap_preboot_get_pages(1);
  
          /* Map the vector page. */
          pmap_preboot_map_pages(systempage, ARM_VECTORS_HIGH,  1);
          if (virtual_end >= ARM_VECTORS_HIGH)
                  virtual_end = ARM_VECTORS_HIGH - 1;
  
          /* Allocate dynamic per-cpu area. */
          dpcpu = pmap_preboot_get_vpages(DPCPU_SIZE / PAGE_SIZE);
          dpcpu_init((void *)dpcpu, 0);
  
          /* Allocate stacks for all modes */
          irqstack    = pmap_preboot_get_vpages(IRQ_STACK_SIZE * MAXCPU);
          abtstack    = pmap_preboot_get_vpages(ABT_STACK_SIZE * MAXCPU);
          undstack    = pmap_preboot_get_vpages(UND_STACK_SIZE * MAXCPU );
          kernelstack = pmap_preboot_get_vpages(kstack_pages);
  
          /* Allocate message buffer. */
          msgbufp = (void *)pmap_preboot_get_vpages(
              round_page(msgbufsize) / PAGE_SIZE);
  
          /*
           * Pages were allocated during the secondary bootstrap for the
           * stacks for different CPU modes.
           * We must now set the r13 registers in the different CPU modes to
           * point to these stacks.
           * Since the ARM stacks use STMFD etc. we must set r13 to the top end
           * of the stack memory.
           */
          set_stackptrs(0);
          mutex_init();
  
          /* Establish static device mappings. */
          err_devmap = platform_devmap_init();
          devmap_bootstrap(0, NULL);
          vm_max_kernel_address = platform_lastaddr();
  
          /*
           * Only after the SOC registers block is mapped we can perform device
           * tree fixups, as they may attempt to read parameters from hardware.
           */
          OF_interpret("perform-fixup", 0);
          platform_gpio_init();
          cninit();
  
          /*
           * If we made a mapping for EARLY_PRINTF after pmap_bootstrap_prepare(),
           * undo it now that the normal console printf works.
           */
  #if defined(EARLY_PRINTF) && defined(SOCDEV_PA) && defined(SOCDEV_VA) && SOCDEV_VA < KERNBASE
          pmap_kremove(SOCDEV_VA);
  #endif
  
          debugf("initarm: console initialized\n");
          debugf(" arg1 kmdp = 0x%08x\n", (uint32_t)kmdp);
          debugf(" boothowto = 0x%08x\n", boothowto);
          debugf(" dtbp = 0x%08x\n", (uint32_t)dtbp);
          debugf(" lastaddr1: 0x%08x\n", lastaddr);
          arm_print_kenv();
  
          env = kern_getenv("kernelname");
          if (env != NULL)
                  strlcpy(kernelname, env, sizeof(kernelname));
  
          if (err_devmap != 0)
                  printf("WARNING: could not fully configure devmap, error=%d\n",
                      err_devmap);
  
          platform_late_init();
  
          /*
           * We must now clean the cache again....
           * Cleaning may be done by reading new data to displace any
           * dirty data in the cache. This will have happened in cpu_setttb()
           * but since we are boot strapping the addresses used for the read
           * may have just been remapped and thus the cache could be out
           * of sync. A re-clean after the switch will cure this.
           * After booting there are no gross relocations of the kernel thus
           * this problem will not occur after initarm().
           */
          /* Set stack for exception handlers */
          undefined_init();
          init_proc0(kernelstack);
          arm_vector_init(ARM_VECTORS_HIGH, ARM_VEC_ALL);
          enable_interrupts(PSR_A);
          pmap_bootstrap(0);
  
          /* Exclude the kernel (and all the things we allocated which immediately
           * follow the kernel) from the VM allocation pool but not from crash
           * dumps.  virtual_avail is a global variable which tracks the kva we've
           * "allocated" while setting up pmaps.
           *
           * Prepare the list of physical memory available to the vm subsystem.
           */
          physmem_exclude_region(abp->abp_physaddr,
                  pmap_preboot_get_pages(0) - abp->abp_physaddr, EXFLAG_NOALLOC);
          physmem_init_kernel_globals();
  
          init_param2(physmem);
          /* Init message buffer. */
          msgbufinit(msgbufp, msgbufsize);
          dbg_monitor_init();
          arm_kdb_init();
          /* Apply possible BP hardening. */
          cpuinfo_init_bp_hardening();
          return ((void *)STACKALIGN(thread0.td_pcb));
  
  }
  
  #endif /* __ARM_ARCH < 6 */
  #endif /* FDT */

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