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 <sys/cdefs.h>
    __FBSDID("$FreeBSD: releng/8.3/sys/arm/arm/machdep.c 231131 2012-02-07 15:50:14Z cognet $");
    
    #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/kernel.h>
    #include <sys/ktr.h>
    #include <sys/linker.h>
    #include <sys/lock.h>
    #include <sys/malloc.h>
    #include <sys/mutex.h>
    #include <sys/pcpu.h>
    #include <sys/ptrace.h>
    #include <sys/signalvar.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 <vm/vnode_pager.h>
    
    #include <machine/armreg.h>
    #include <machine/cpu.h>
    #include <machine/machdep.h>
    #include <machine/md_var.h>
    #include <machine/metadata.h>
    #include <machine/pcb.h>
    #include <machine/pmap.h>
    #include <machine/reg.h>
    #include <machine/trap.h>
    #include <machine/undefined.h>
    #include <machine/vmparam.h>
    #include <machine/sysarch.h>
    
    uint32_t cpu_reset_address = 0;
    int cold = 1;
    vm_offset_t vector_page;
    
    long realmem = 0;
   
   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
   
   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_flags & 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;
   #ifndef ARM_CACHE_LOCK_ENABLE
           vm_page_t m;
   #endif
   
           cpu_setup("");
           identify_arm_cpu();
   
           printf("real memory  = %ju (%ju MB)\n", (uintmax_t)ptoa(physmem),
               (uintmax_t)ptoa(physmem) / 1048576);
           realmem = physmem;
   
           /*
            * Display the RAM layout.
            */
           if (bootverbose) {
                   int indx;
   
                   printf("Physical memory chunk(s):\n");
                   for (indx = 0; phys_avail[indx + 1] != 0; indx += 2) {
                           vm_paddr_t size;
   
                           size = phys_avail[indx + 1] - phys_avail[indx];
                           printf("%#08jx - %#08jx, %ju bytes (%ju pages)\n",
                               (uintmax_t)phys_avail[indx],
                               (uintmax_t)phys_avail[indx + 1] - 1,
                               (uintmax_t)size, (uintmax_t)size / PAGE_SIZE);
                   }
           }
   
           vm_ksubmap_init(&kmi);
   
           printf("avail memory = %ju (%ju MB)\n",
               (uintmax_t)ptoa(cnt.v_free_count),
               (uintmax_t)ptoa(cnt.v_free_count) / 1048576);
   
           bufinit();
           vm_pager_bufferinit();
           pcb->un_32.pcb32_und_sp = (u_int)thread0.td_kstack +
               USPACE_UNDEF_STACK_TOP;
           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_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;
   }
   
   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);
           cpu_l2cache_wb_range((uintptr_t)ptr, len);
   }
   
   /* 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)
   {
           cpu_sleep(0);
   }
   
   int
   cpu_idle_wakeup(int cpu)
   {
   
           return (0);
   }
   
   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, u_long entry, u_long stack, u_long ps_strings)
   {
           struct trapframe *tf = td->td_frame;
   
           memset(tf, 0, sizeof(*tf));
           tf->tf_usr_sp = stack;
           tf->tf_usr_lr = entry;
           tf->tf_svc_lr = 0x77777777;
           tf->tf_pc = entry;
           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
   sigreturn(td, uap)
           struct thread *td;
           struct sigreturn_args /* {
                   const struct __ucontext *sigcntxp;
           } */ *uap;
   {
           struct sigframe sf;
           struct trapframe *tf;
           int spsr;
           
           if (uap == NULL)
                   return (EFAULT);
           if (copyin(uap->sigcntxp, &sf, sizeof(sf)))
                   return (EFAULT);
           /*
            * Make sure the processor mode has not been tampered with and
            * interrupts have not been disabled.
            */
           spsr = sf.sf_uc.uc_mcontext.__gregs[_REG_CPSR];
           if ((spsr & PSR_MODE) != PSR_USR32_MODE ||
               (spsr & (I32_bit | F32_bit)) != 0)
                   return (EINVAL);
                   /* Restore register context. */
           tf = td->td_frame;
           set_mcontext(td, &sf.sf_uc.uc_mcontext);
   
           /* Restore signal mask. */
           kern_sigprocmask(td, SIG_SETMASK, &sf.sf_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(void)
   {
   #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("elf kernel") + 1;
           strcpy((char*)&fake_preload[i++], "elf kernel");
           i += 2;
           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);
   }

Cache object: 3a26ecfb65376545ef23594a6c5edc80