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 $        */
     
     /*-
      * 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 dependant functions for kernel setup
     *
     * Created      : 17/09/94
     * Updated      : 18/04/01 updated for new wscons
     */
    
    #include "opt_compat.h"
    #include "opt_ddb.h"
    #include "opt_platform.h"
    #include "opt_sched.h"
    #include "opt_timer.h"
    
    #include <sys/cdefs.h>
    __FBSDID("$FreeBSD: releng/10.1/sys/arm/arm/machdep.c 270077 2014-08-17 01:48:12Z ian $");
    
    #include <sys/param.h>
    #include <sys/proc.h>
    #include <sys/systm.h>
    #include <sys/bio.h>
    #include <sys/buf.h>
    #include <sys/bus.h>
    #include <sys/cons.h>
    #include <sys/cpu.h>
    #include <sys/exec.h>
    #include <sys/imgact.h>
    #include <sys/kdb.h>
    #include <sys/kernel.h>
    #include <sys/ktr.h>
    #include <sys/linker.h>
    #include <sys/lock.h>
    #include <sys/malloc.h>
    #include <sys/msgbuf.h>
    #include <sys/mutex.h>
    #include <sys/pcpu.h>
    #include <sys/ptrace.h>
    #include <sys/rwlock.h>
    #include <sys/sched.h>
    #include <sys/signalvar.h>
    #include <sys/syscallsubr.h>
    #include <sys/sysctl.h>
    #include <sys/sysent.h>
    #include <sys/sysproto.h>
    #include <sys/uio.h>
    
    #include <vm/vm.h>
    #include <vm/pmap.h>
    #include <vm/vm_map.h>
    #include <vm/vm_object.h>
    #include <vm/vm_page.h>
    #include <vm/vm_pager.h>
    
    #include <machine/armreg.h>
    #include <machine/atags.h>
    #include <machine/cpu.h>
    #include <machine/devmap.h>
    #include <machine/frame.h>
    #include <machine/intr.h>
    #include <machine/machdep.h>
    #include <machine/md_var.h>
    #include <machine/metadata.h>
    #include <machine/pcb.h>
   #include <machine/physmem.h>
   #include <machine/reg.h>
   #include <machine/trap.h>
   #include <machine/undefined.h>
   #include <machine/vfp.h>
   #include <machine/vmparam.h>
   #include <machine/sysarch.h>
   
   #ifdef FDT
   #include <dev/fdt/fdt_common.h>
   #include <dev/ofw/openfirm.h>
   #endif
   
   #ifdef DEBUG
   #define debugf(fmt, args...) printf(fmt, ##args)
   #else
   #define debugf(fmt, args...)
   #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;
   
   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 DDB
   extern vm_offset_t ksym_start, ksym_end;
   #endif
   
   #ifdef FDT
   /*
    * 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];
   
   vm_paddr_t pmap_pa;
   
   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
   
   #if defined(LINUX_BOOT_ABI)
   #define LBABI_MAX_BANKS 10
   
   uint32_t board_id;
   struct arm_lbabi_tag *atag_list;
   char linux_command_line[LBABI_MAX_COMMAND_LINE + 1];
   char atags[LBABI_MAX_COMMAND_LINE * 2];
   uint32_t memstart[LBABI_MAX_BANKS];
   uint32_t memsize[LBABI_MAX_BANKS];
   uint32_t membanks;
   #endif
   
   static uint32_t board_revision;
   /* hex representation of uint64_t */
   static char board_serial[32];
   
   SYSCTL_NODE(_hw, OID_AUTO, board, CTLFLAG_RD, 0, "Board attributes");
   SYSCTL_UINT(_hw_board, OID_AUTO, revision, CTLFLAG_RD,
       &board_revision, 0, "Board revision");
   SYSCTL_STRING(_hw_board, OID_AUTO, serial, CTLFLAG_RD,
       board_serial, 0, "Board serial");
   
   int vfp_exists;
   SYSCTL_INT(_hw, HW_FLOATINGPT, floatingpoint, CTLFLAG_RD,
       &vfp_exists, 0, "Floating point support enabled");
   
   void
   board_set_serial(uint64_t serial)
   {
   
           snprintf(board_serial, sizeof(board_serial)-1, 
                       "%016jx", serial);
   }
   
   void
   board_set_revision(uint32_t revision)
   {
   
           board_revision = revision;
   }
   
   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;
           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 *)(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. */
           get_mcontext(td, &frame.sf_uc.uc_mcontext, 0);
           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);
           }
   
           /* Translate the signal if appropriate. */
           if (p->p_sysent->sv_sigtbl && sig <= p->p_sysent->sv_sigsize)
                   sig = p->p_sysent->sv_sigtbl[_SIG_IDX(sig)];
   
           /*
            * 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;
           tf->tf_usr_lr = (register_t)(PS_STRINGS - *(p->p_sysent->sv_szsigcode));
   
           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);
   }
   
   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. */
           cpu_icache_sync_range(va, (ARM_NVEC * 2) * sizeof(u_int));
   
           vector_page = va;
   
           if (va == ARM_VECTORS_HIGH) {
                   /*
                    * 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) ...
                    *
                    * NOTE: If the CPU control register is not readable,
                    * this will totally fail!  We'll just assume that
                    * any system that has high vector support has a
                    * readable CPU control register, for now.  If we
                    * ever encounter one that does not, we'll have to
                    * rethink this.
                    */
                   cpu_control(CPU_CONTROL_VECRELOC, CPU_CONTROL_VECRELOC);
           }
   }
   
   static void
   cpu_startup(void *dummy)
   {
           struct pcb *pcb = thread0.td_pcb;
           const unsigned int mbyte = 1024 * 1024;
   #ifdef ARM_TP_ADDRESS
   #ifndef ARM_CACHE_LOCK_ENABLE
           vm_page_t m;
   #endif
   #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(cnt.v_free_count),
               (uintmax_t)arm32_ptob(cnt.v_free_count) / mbyte);
           if (bootverbose) {
                   arm_physmem_print_tables();
                   arm_devmap_print_table();
           }
   
           bufinit();
           vm_pager_bufferinit();
           pcb->un_32.pcb32_sp = (u_int)thread0.td_kstack +
               USPACE_SVC_STACK_TOP;
           vector_page_setprot(VM_PROT_READ);
           pmap_set_pcb_pagedir(pmap_kernel(), pcb);
           pmap_postinit();
   #ifdef ARM_TP_ADDRESS
   #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)
   {
   
           cpu_dcache_wb_range((uintptr_t)ptr, len);
   #ifdef ARM_L2_PIPT
           cpu_l2cache_wb_range((uintptr_t)vtophys(ptr), len);
   #else
           cpu_l2cache_wb_range((uintptr_t)ptr, len);
   #endif
   }
   
   /* Get current clock frequency for the given cpu id. */
   int
   cpu_est_clockrate(int cpu_id, uint64_t *rate)
   {
   
           return (ENXIO);
   }
   
   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);
   }
   
   /*
    * 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)
   {
   
   #ifndef NO_EVENTTIMERS
   #ifdef SMP
           if (PCPU_GET(cpuid) == 0)
                   cpu_initclocks_bsp();
           else
                   cpu_initclocks_ap();
   #else
           cpu_initclocks_bsp();
   #endif
   #endif
   }
   __weak_reference(arm_generic_initclocks, cpu_initclocks);
   
   int
   fill_regs(struct thread *td, struct reg *regs)
   {
           struct trapframe *tf = td->td_frame;
           bcopy(&tf->tf_r0, regs->r, sizeof(regs->r));
           regs->r_sp = tf->tf_usr_sp;
           regs->r_lr = tf->tf_usr_lr;
           regs->r_pc = tf->tf_pc;
           regs->r_cpsr = tf->tf_spsr;
           return (0);
   }
   int
   fill_fpregs(struct thread *td, struct fpreg *regs)
   {
           bzero(regs, sizeof(*regs));
           return (0);
   }
   
   int
   set_regs(struct thread *td, struct reg *regs)
   {
           struct trapframe *tf = td->td_frame;
           
           bcopy(regs->r, &tf->tf_r0, sizeof(regs->r));
           tf->tf_usr_sp = regs->r_sp;
           tf->tf_usr_lr = regs->r_lr;
           tf->tf_pc = regs->r_pc;
           tf->tf_spsr &=  ~PSR_FLAGS;
           tf->tf_spsr |= regs->r_cpsr & PSR_FLAGS;
           return (0);                                                             
   }
   
   int
   set_fpregs(struct thread *td, struct fpreg *regs)
   {
           return (0);
   }
   
   int
   fill_dbregs(struct thread *td, struct dbreg *regs)
   {
           return (0);
   }
   int
   set_dbregs(struct thread *td, struct dbreg *regs)
   {
           return (0);
   }
   
   
   static int
   ptrace_read_int(struct thread *td, vm_offset_t addr, u_int32_t *v)
   {
           struct iovec iov;
           struct uio uio;
   
           PROC_LOCK_ASSERT(td->td_proc, MA_NOTOWNED);
           iov.iov_base = (caddr_t) v;
           iov.iov_len = sizeof(u_int32_t);
           uio.uio_iov = &iov;
           uio.uio_iovcnt = 1;
           uio.uio_offset = (off_t)addr;
           uio.uio_resid = sizeof(u_int32_t);
           uio.uio_segflg = UIO_SYSSPACE;
           uio.uio_rw = UIO_READ;
           uio.uio_td = td;
           return proc_rwmem(td->td_proc, &uio);
   }
   
   static int
   ptrace_write_int(struct thread *td, vm_offset_t addr, u_int32_t v)
   {
           struct iovec iov;
           struct uio uio;
   
           PROC_LOCK_ASSERT(td->td_proc, MA_NOTOWNED);
           iov.iov_base = (caddr_t) &v;
           iov.iov_len = sizeof(u_int32_t);
           uio.uio_iov = &iov;
           uio.uio_iovcnt = 1;
           uio.uio_offset = (off_t)addr;
           uio.uio_resid = sizeof(u_int32_t);
           uio.uio_segflg = UIO_SYSSPACE;
           uio.uio_rw = UIO_WRITE;
           uio.uio_td = td;
           return proc_rwmem(td->td_proc, &uio);
   }
   
   int
   ptrace_single_step(struct thread *td)
   {
           struct proc *p;
           int error;
           
           KASSERT(td->td_md.md_ptrace_instr == 0,
            ("Didn't clear single step"));
           p = td->td_proc;
           PROC_UNLOCK(p);
           error = ptrace_read_int(td, td->td_frame->tf_pc + 4,
               &td->td_md.md_ptrace_instr);
           if (error)
                   goto out;
           error = ptrace_write_int(td, td->td_frame->tf_pc + 4,
               PTRACE_BREAKPOINT);
           if (error)
                   td->td_md.md_ptrace_instr = 0;
           td->td_md.md_ptrace_addr = td->td_frame->tf_pc + 4;
   out:
           PROC_LOCK(p);
           return (error);
   }
   
   int
   ptrace_clear_single_step(struct thread *td)
   {
           struct proc *p;
   
           if (td->td_md.md_ptrace_instr) {
                   p = td->td_proc;
                   PROC_UNLOCK(p);
                   ptrace_write_int(td, td->td_md.md_ptrace_addr,
                       td->td_md.md_ptrace_instr);
                   PROC_LOCK(p);
                   td->td_md.md_ptrace_instr = 0;
           }
           return (0);
   }
   
   int
   ptrace_set_pc(struct thread *td, unsigned long addr)
   {
           td->td_frame->tf_pc = addr;
           return (0);
   }
   
   void
   cpu_pcpu_init(struct pcpu *pcpu, int cpuid, size_t size)
   {
   }
   
   void
   spinlock_enter(void)
   {
           struct thread *td;
           register_t cspr;
   
           td = curthread;
           if (td->td_md.md_spinlock_count == 0) {
                   cspr = disable_interrupts(I32_bit | F32_bit);
                   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;
   }
   
   /*
    * 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;
           else
                   gr[_REG_R0]   = tf->tf_r0;
           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;
           gr[_REG_CPSR] = tf->tf_spsr;
   
           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, const mcontext_t *mcp)
   {
           struct trapframe *tf = td->td_frame;
           const __greg_t *gr = mcp->__gregs;
   
           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];
   
           return (0);
   }
   
   /*
    * MPSAFE
    */
   int
   sys_sigreturn(td, uap)
           struct thread *td;
           struct sigreturn_args /* {
                   const struct __ucontext *sigcntxp;
           } */ *uap;
   {
           ucontext_t uc;
           int spsr;
           
           if (uap == NULL)
                   return (EFAULT);
           if (copyin(uap->sigcntxp, &uc, sizeof(uc)))
                   return (EFAULT);
           /*
            * Make sure the processor mode has not been tampered with and
            * interrupts have not been disabled.
            */
           spsr = uc.uc_mcontext.__gregs[_REG_CPSR];
           if ((spsr & PSR_MODE) != PSR_USR32_MODE ||
               (spsr & (I32_bit | F32_bit)) != 0)
                   return (EINVAL);
                   /* Restore register context. */
           set_mcontext(td, &uc.uc_mcontext);
   
           /* 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->un_32.pcb32_r8 = tf->tf_r8;
           pcb->un_32.pcb32_r9 = tf->tf_r9;
           pcb->un_32.pcb32_r10 = tf->tf_r10;
           pcb->un_32.pcb32_r11 = tf->tf_r11;
           pcb->un_32.pcb32_r12 = tf->tf_r12;
           pcb->un_32.pcb32_pc = tf->tf_pc;
           pcb->un_32.pcb32_lr = tf->tf_usr_lr;
           pcb->un_32.pcb32_sp = tf->tf_usr_sp;
   }
   
   /*
    * Fake up a boot descriptor table
    */
   vm_offset_t
   fake_preload_metadata(struct arm_boot_params *abp __unused)
   {
   #ifdef DDB
           vm_offset_t zstart = 0, zend = 0;
   #endif
           vm_offset_t lastaddr;
           int i = 0;
           static uint32_t fake_preload[35];
   
           fake_preload[i++] = MODINFO_NAME;
           fake_preload[i++] = strlen("kernel") + 1;
           strcpy((char*)&fake_preload[i++], "kernel");
           i += 1;
           fake_preload[i++] = MODINFO_TYPE;
           fake_preload[i++] = strlen("elf kernel") + 1;
           strcpy((char*)&fake_preload[i++], "elf kernel");
           i += 2;
           fake_preload[i++] = MODINFO_ADDR;
           fake_preload[i++] = sizeof(vm_offset_t);
           fake_preload[i++] = KERNVIRTADDR;
           fake_preload[i++] = MODINFO_SIZE;
           fake_preload[i++] = sizeof(uint32_t);
           fake_preload[i++] = (uint32_t)&end - KERNVIRTADDR;
   #ifdef DDB
           if (*(uint32_t *)KERNVIRTADDR == MAGIC_TRAMP_NUMBER) {
                   fake_preload[i++] = MODINFO_METADATA|MODINFOMD_SSYM;
                   fake_preload[i++] = sizeof(vm_offset_t);
                   fake_preload[i++] = *(uint32_t *)(KERNVIRTADDR + 4);
                   fake_preload[i++] = MODINFO_METADATA|MODINFOMD_ESYM;
                   fake_preload[i++] = sizeof(vm_offset_t);
                   fake_preload[i++] = *(uint32_t *)(KERNVIRTADDR + 8);
                   lastaddr = *(uint32_t *)(KERNVIRTADDR + 8);
                   zend = lastaddr;
                   zstart = *(uint32_t *)(KERNVIRTADDR + 4);
                   ksym_start = zstart;
                   ksym_end = zend;
           } else
   #endif
                   lastaddr = (vm_offset_t)&end;
           fake_preload[i++] = 0;
           fake_preload[i] = 0;
           preload_metadata = (void *)fake_preload;
   
           return (lastaddr);
   }
   
   void
   pcpu0_init(void)
   {
   #if ARM_ARCH_6 || ARM_ARCH_7A || defined(CPU_MV_PJ4B)
           set_curthread(&thread0);
   #endif
           pcpu_init(pcpup, 0, sizeof(struct pcpu));
           PCPU_SET(curthread, &thread0);
   #ifdef VFP
           PCPU_SET(cpu, 0);
   #endif
   }
   
   #if defined(LINUX_BOOT_ABI)
   vm_offset_t
   linux_parse_boot_param(struct arm_boot_params *abp)
   {
           struct arm_lbabi_tag *walker;
           uint32_t revision;
           uint64_t serial;
   
           /*
            * Linux boot ABI: r0 = 0, r1 is the board type (!= 0) and r2
            * is atags or dtb pointer.  If all of these aren't satisfied,
            * then punt.
            */
           if (!(abp->abp_r0 == 0 && abp->abp_r1 != 0 && abp->abp_r2 != 0))
                   return 0;
   
           board_id = abp->abp_r1;
           walker = (struct arm_lbabi_tag *)
               (abp->abp_r2 + KERNVIRTADDR - abp->abp_physaddr);
   
           /* xxx - Need to also look for binary device tree */
           if (ATAG_TAG(walker) != ATAG_CORE)
                   return 0;
   
           atag_list = walker;
           while (ATAG_TAG(walker) != ATAG_NONE) {
                   switch (ATAG_TAG(walker)) {
                   case ATAG_CORE:
                           break;
                   case ATAG_MEM:
                           arm_physmem_hardware_region(walker->u.tag_mem.start,
                               walker->u.tag_mem.size);
                           break;
                   case ATAG_INITRD2:
                           break;
                   case ATAG_SERIAL:
                           serial = walker->u.tag_sn.low |
                               ((uint64_t)walker->u.tag_sn.high << 32);
                           board_set_serial(serial);
                           break;
                   case ATAG_REVISION:
                           revision = walker->u.tag_rev.rev;
                           board_set_revision(revision);
                           break;
                   case ATAG_CMDLINE:
                           /* XXX open question: Parse this for boothowto? */
                           bcopy(walker->u.tag_cmd.command, linux_command_line,
                                 ATAG_SIZE(walker));
                           break;
                   default:
                           break;
                   }
                   walker = ATAG_NEXT(walker);
           }
   
           /* Save a copy for later */
           bcopy(atag_list, atags,
               (char *)walker - (char *)atag_list + ATAG_SIZE(walker));
   
           return fake_preload_metadata(abp);
   }
   #endif
   
   #if defined(FREEBSD_BOOT_LOADER)
   vm_offset_t
   freebsd_parse_boot_param(struct arm_boot_params *abp)
   {
           vm_offset_t lastaddr = 0;
           void *mdp;
           void *kmdp;
   
           /*
            * Mask metadata pointer: it is supposed to be on page boundary. If
            * the first argument (mdp) doesn't point to a valid address the
            * bootloader must have passed us something else than the metadata
            * ptr, so we give up.  Also give up if we cannot find metadta section
            * the loader creates that we get all this data out of.
            */
   
           if ((mdp = (void *)(abp->abp_r0 & ~PAGE_MASK)) == NULL)
                   return 0;
           preload_metadata = mdp;
           kmdp = preload_search_by_type("elf kernel");
           if (kmdp == NULL)
                   return 0;
   
           boothowto = MD_FETCH(kmdp, MODINFOMD_HOWTO, int);
           kern_envp = MD_FETCH(kmdp, MODINFOMD_ENVP, char *);
           lastaddr = MD_FETCH(kmdp, MODINFOMD_KERNEND, vm_offset_t);
   #ifdef DDB
           ksym_start = MD_FETCH(kmdp, MODINFOMD_SSYM, uintptr_t);
           ksym_end = MD_FETCH(kmdp, MODINFOMD_ESYM, uintptr_t);
   #endif
           preload_addr_relocate = KERNVIRTADDR - abp->abp_physaddr;
           return lastaddr;
   }
   #endif
   
   vm_offset_t
   default_parse_boot_param(struct arm_boot_params *abp)
   {
           vm_offset_t lastaddr;
   
   #if defined(LINUX_BOOT_ABI)
           if ((lastaddr = linux_parse_boot_param(abp)) != 0)
                   return lastaddr;
   #endif
   #if defined(FREEBSD_BOOT_LOADER)
           if ((lastaddr = freebsd_parse_boot_param(abp)) != 0)
                   return lastaddr;
   #endif
           /* Fall back to hardcoded metadata. */
           lastaddr = fake_preload_metadata(abp);
   
           return lastaddr;
   }
   
   /*
    * Stub version of the boot parameter parsing routine.  We are
    * called early in initarm, before even VM has been initialized.
    * This routine needs to preserve any data that the boot loader
    * has passed in before the kernel starts to grow past the end
    * of the BSS, traditionally the place boot-loaders put this data.
    *
    * Since this is called so early, things that depend on the vm system
    * being setup (including access to some SoC's serial ports), about
    * all that can be done in this routine is to copy the arguments.
    *
    * This is the default boot parameter parsing routine.  Individual
    * kernels/boards can override this weak function with one of their
    * own.  We just fake metadata...
    */
   __weak_reference(default_parse_boot_param, parse_boot_param);
   
   /*
    * Initialize proc0
    */
   void
   init_proc0(vm_offset_t kstack)
   {
           proc_linkup0(&proc0, &thread0);
           thread0.td_kstack = kstack;
           thread0.td_pcb = (struct pcb *)
                   (thread0.td_kstack + 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 | VFPSCR_FZ;
           thread0.td_frame = &proc0_tf;
           pcpup->pc_curpcb = thread0.td_pcb;
   }
   
   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)));
  }
  
  #ifdef FDT
  static char *
  kenv_next(char *cp)
  {
  
          if (cp != NULL) {
                  while (*cp != 0)
                          cp++;
                  cp++;
                  if (*cp == 0)
                          cp = NULL;
          }
          return (cp);
  }
  
  static void
  print_kenv(void)
  {
          int len;
          char *cp;
  
          debugf("loader passed (static) kenv:\n");
          if (kern_envp == NULL) {
                  debugf(" no env, null ptr\n");
                  return;
          }
          debugf(" kern_envp = 0x%08x\n", (uint32_t)kern_envp);
  
          len = 0;
          for (cp = kern_envp; cp != NULL; cp = kenv_next(cp))
                  debugf(" %x %s\n", (uint32_t)cp, cp);
  }
  
  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;
          uint32_t memsize, 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;
          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");
          arm_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)
                  arm_physmem_exclude_regions(mem_regions, mem_regions_sz, 
                      EXFLAG_NODUMP | EXFLAG_NOALLOC);
  
          /* Platform-specific initialisation */
          initarm_early_init();
  
          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 and one for vectors map.
           */
          l2size += 3;
  
          /* 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 * MAXCPU);
          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 = initarm_devmap_init();
          arm_devmap_bootstrap(l1pagetable, NULL);
          vm_max_kernel_address = initarm_lastaddr();
  
          cpu_domains((DOMAIN_CLIENT << (PMAP_DOMAIN_KERNEL * 2)) | DOMAIN_CLIENT);
          pmap_pa = kernel_l1pt.pv_pa;
          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);
  
          initarm_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);
          print_kenv();
  
          env = 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);
  
          initarm_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 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.
           */
          arm_physmem_exclude_region(abp->abp_physaddr, 
              (virtual_avail - KERNVIRTADDR), EXFLAG_NOALLOC);
          arm_physmem_init_kernel_globals();
  
          init_param2(physmem);
          kdb_init();
  
          return ((void *)(kernelstack.pv_va + USPACE_SVC_STACK_TOP -
              sizeof(struct pcb)));
  }
  #endif

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