xref: /freebsd-10.1-release/sys/arm/arm/elf_trampoline.c

/*-
 * Copyright (c) 2005 Olivier Houchard.  All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * 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 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.
 */

/*
 * Since we are compiled outside of the normal kernel build process, we
 * need to include opt_global.h manually.
 */
#include "opt_global.h"
#include "opt_kernname.h"

#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include <machine/asm.h>
#include <sys/param.h>
#include <sys/elf32.h>
#include <sys/inflate.h>
#include <machine/elf.h>
#include <machine/pte.h>
#include <machine/cpufunc.h>
#include <machine/armreg.h>

extern char kernel_start[];
extern char kernel_end[];

extern void *_end;

void _start(void);
void __start(void);
void __startC(void);

extern unsigned int cpufunc_id(void);
extern void armv6_idcache_wbinv_all(void);
extern void armv7_idcache_wbinv_all(void);
extern void do_call(void *, void *, void *, int);

#define GZ_HEAD	0xa

#if defined(CPU_ARM9)
#define cpu_idcache_wbinv_all	arm9_idcache_wbinv_all
extern void arm9_idcache_wbinv_all(void);
#elif defined(CPU_FA526) || defined(CPU_FA626TE)
#define cpu_idcache_wbinv_all	fa526_idcache_wbinv_all
extern void fa526_idcache_wbinv_all(void);
#elif defined(CPU_ARM9E)
#define cpu_idcache_wbinv_all	armv5_ec_idcache_wbinv_all
extern void armv5_ec_idcache_wbinv_all(void);
#elif defined(CPU_ARM10)
#define cpu_idcache_wbinv_all	arm10_idcache_wbinv_all
extern void arm10_idcache_wbinv_all(void);
#elif defined(CPU_ARM1136) || defined(CPU_ARM1176)
#define cpu_idcache_wbinv_all	armv6_idcache_wbinv_all
#elif defined(CPU_XSCALE_80200) || defined(CPU_XSCALE_80321) || \
  defined(CPU_XSCALE_PXA2X0) || defined(CPU_XSCALE_IXP425) ||	\
  defined(CPU_XSCALE_80219)
#define cpu_idcache_wbinv_all	xscale_cache_purgeID
extern void xscale_cache_purgeID(void);
#elif defined(CPU_XSCALE_81342)
#define cpu_idcache_wbinv_all	xscalec3_cache_purgeID
extern void xscalec3_cache_purgeID(void);
#elif defined(CPU_MV_PJ4B)
#if !defined(SOC_MV_ARMADAXP)
#define cpu_idcache_wbinv_all	armv6_idcache_wbinv_all
extern void armv6_idcache_wbinv_all(void);
#else
#define cpu_idcache_wbinv_all()	armadaxp_idcache_wbinv_all
#endif
#endif /* CPU_MV_PJ4B */
#ifdef CPU_XSCALE_81342
#define cpu_l2cache_wbinv_all	xscalec3_l2cache_purge
extern void xscalec3_l2cache_purge(void);
#elif defined(SOC_MV_KIRKWOOD) || defined(SOC_MV_DISCOVERY)
#define cpu_l2cache_wbinv_all	sheeva_l2cache_wbinv_all
extern void sheeva_l2cache_wbinv_all(void);
#elif defined(CPU_CORTEXA) || defined(CPU_KRAIT)
#define cpu_idcache_wbinv_all	armv7_idcache_wbinv_all
#define cpu_l2cache_wbinv_all()
#else
#define cpu_l2cache_wbinv_all()
#endif

static void armadaxp_idcache_wbinv_all(void);

int     arm_picache_size;
int     arm_picache_line_size;
int     arm_picache_ways;

int     arm_pdcache_size;       /* and unified */
int     arm_pdcache_line_size = 32;
int     arm_pdcache_ways;

int     arm_pcache_type;
int     arm_pcache_unified;

int     arm_dcache_align;
int     arm_dcache_align_mask;

u_int	arm_cache_level;
u_int	arm_cache_type[14];
u_int	arm_cache_loc;

/* Additional cache information local to this file.  Log2 of some of the
      above numbers.  */
static int      arm_dcache_l2_nsets;
static int      arm_dcache_l2_assoc;
static int      arm_dcache_l2_linesize;


int block_userspace_access = 0;
extern int arm9_dcache_sets_inc;
extern int arm9_dcache_sets_max;
extern int arm9_dcache_index_max;
extern int arm9_dcache_index_inc;

static __inline void *
memcpy(void *dst, const void *src, int len)
{
	const char *s = src;
    	char *d = dst;

	while (len) {
		if (0 && len >= 4 && !((vm_offset_t)d & 3) &&
		    !((vm_offset_t)s & 3)) {
			*(uint32_t *)d = *(uint32_t *)s;
			s += 4;
			d += 4;
			len -= 4;
		} else {
			*d++ = *s++;
			len--;
		}
	}
	return (dst);
}

static __inline void
bzero(void *addr, int count)
{
	char *tmp = (char *)addr;

	while (count > 0) {
		if (count >= 4 && !((vm_offset_t)tmp & 3)) {
			*(uint32_t *)tmp = 0;
			tmp += 4;
			count -= 4;
		} else {
			*tmp = 0;
			tmp++;
			count--;
		}
	}
}

static void arm9_setup(void);

void
_startC(void)
{
	int tmp1;
	unsigned int sp = ((unsigned int)&_end & ~3) + 4;
	unsigned int pc, kernphysaddr;

	/*
	 * Figure out the physical address the kernel was loaded at.  This
	 * assumes the entry point (this code right here) is in the first page,
	 * which will always be the case for this trampoline code.
	 */
	__asm __volatile("mov %0, pc\n"
	    : "=r" (pc));
	kernphysaddr = pc & ~PAGE_MASK;

#if defined(FLASHADDR) && defined(PHYSADDR) && defined(LOADERRAMADDR)
	if ((FLASHADDR > LOADERRAMADDR && pc >= FLASHADDR) ||
	    (FLASHADDR < LOADERRAMADDR && pc < LOADERRAMADDR)) {
		/*
		 * We're running from flash, so just copy the whole thing
		 * from flash to memory.
		 * This is far from optimal, we could do the relocation or
		 * the unzipping directly from flash to memory to avoid this
		 * needless copy, but it would require to know the flash
		 * physical address.
		 */
		unsigned int target_addr;
		unsigned int tmp_sp;
		uint32_t src_addr = (uint32_t)&_start - PHYSADDR + FLASHADDR
		    + (pc - FLASHADDR - ((uint32_t)&_startC - PHYSADDR)) & 0xfffff000;

		target_addr = (unsigned int)&_start - PHYSADDR + LOADERRAMADDR;
		tmp_sp = target_addr + 0x100000 +
		    (unsigned int)&_end - (unsigned int)&_start;
		memcpy((char *)target_addr, (char *)src_addr,
		    (unsigned int)&_end - (unsigned int)&_start);
		/* Temporary set the sp and jump to the new location. */
		__asm __volatile(
		    "mov sp, %1\n"
		    "mov pc, %0\n"
		    : : "r" (target_addr), "r" (tmp_sp));

	}
#endif
#ifdef KZIP
	sp += KERNSIZE + 0x100;
	sp &= ~(L1_TABLE_SIZE - 1);
	sp += 2 * L1_TABLE_SIZE;
#endif
	sp += 1024 * 1024; /* Should be enough for a stack */

	__asm __volatile("adr %0, 2f\n"
	    		 "bic %0, %0, #0xff000000\n"
			 "and %1, %1, #0xff000000\n"
			 "orr %0, %0, %1\n"
			 "mrc p15, 0, %1, c1, c0, 0\n"
			 "bic %1, %1, #1\n" /* Disable MMU */
			 "orr %1, %1, #(4 | 8)\n" /* Add DC enable,
						     WBUF enable */
			 "orr %1, %1, #0x1000\n" /* Add IC enable */
			 "orr %1, %1, #(0x800)\n" /* BPRD enable */

			 "mcr p15, 0, %1, c1, c0, 0\n"
			 "nop\n"
			 "nop\n"
			 "nop\n"
			 "mov pc, %0\n"
			 "2: nop\n"
			 "mov sp, %2\n"
			 : "=r" (tmp1), "+r" (kernphysaddr), "+r" (sp));
#ifndef KZIP
#ifdef CPU_ARM9
	/* So that idcache_wbinv works; */
	if ((cpufunc_id() & 0x0000f000) == 0x00009000)
		arm9_setup();
#endif
#endif
	__start();
}

static void
get_cachetype_cp15()
{
	u_int ctype, isize, dsize, cpuid;
	u_int clevel, csize, i, sel;
	u_int multiplier;
	u_char type;

	__asm __volatile("mrc p15, 0, %0, c0, c0, 1"
		: "=r" (ctype));

	cpuid = cpufunc_id();
	/*
	 * ...and thus spake the ARM ARM:
	 *
	 * If an <opcode2> value corresponding to an unimplemented or
	 * reserved ID register is encountered, the System Control
	 * processor returns the value of the main ID register.
	 */
	if (ctype == cpuid)
		goto out;

	if (CPU_CT_FORMAT(ctype) == CPU_CT_ARMV7) {
		__asm __volatile("mrc p15, 1, %0, c0, c0, 1"
		    : "=r" (clevel));
		arm_cache_level = clevel;
		arm_cache_loc = CPU_CLIDR_LOC(arm_cache_level) + 1;
		i = 0;
		while ((type = (clevel & 0x7)) && i < 7) {
			if (type == CACHE_DCACHE || type == CACHE_UNI_CACHE ||
			    type == CACHE_SEP_CACHE) {
				sel = i << 1;
				__asm __volatile("mcr p15, 2, %0, c0, c0, 0"
				    : : "r" (sel));
				__asm __volatile("mrc p15, 1, %0, c0, c0, 0"
				    : "=r" (csize));
				arm_cache_type[sel] = csize;
			}
			if (type == CACHE_ICACHE || type == CACHE_SEP_CACHE) {
				sel = (i << 1) | 1;
				__asm __volatile("mcr p15, 2, %0, c0, c0, 0"
				    : : "r" (sel));
				__asm __volatile("mrc p15, 1, %0, c0, c0, 0"
				    : "=r" (csize));
				arm_cache_type[sel] = csize;
			}
			i++;
			clevel >>= 3;
		}
	} else {
		if ((ctype & CPU_CT_S) == 0)
			arm_pcache_unified = 1;

		/*
		 * If you want to know how this code works, go read the ARM ARM.
		 */

		arm_pcache_type = CPU_CT_CTYPE(ctype);

		if (arm_pcache_unified == 0) {
			isize = CPU_CT_ISIZE(ctype);
			multiplier = (isize & CPU_CT_xSIZE_M) ? 3 : 2;
			arm_picache_line_size = 1U << (CPU_CT_xSIZE_LEN(isize) + 3);
			if (CPU_CT_xSIZE_ASSOC(isize) == 0) {
				if (isize & CPU_CT_xSIZE_M)
					arm_picache_line_size = 0; /* not present */
				else
					arm_picache_ways = 1;
			} else {
				arm_picache_ways = multiplier <<
				    (CPU_CT_xSIZE_ASSOC(isize) - 1);
			}
			arm_picache_size = multiplier << (CPU_CT_xSIZE_SIZE(isize) + 8);
		}

		dsize = CPU_CT_DSIZE(ctype);
		multiplier = (dsize & CPU_CT_xSIZE_M) ? 3 : 2;
		arm_pdcache_line_size = 1U << (CPU_CT_xSIZE_LEN(dsize) + 3);
		if (CPU_CT_xSIZE_ASSOC(dsize) == 0) {
			if (dsize & CPU_CT_xSIZE_M)
				arm_pdcache_line_size = 0; /* not present */
			else
				arm_pdcache_ways = 1;
		} else {
			arm_pdcache_ways = multiplier <<
			    (CPU_CT_xSIZE_ASSOC(dsize) - 1);
		}
		arm_pdcache_size = multiplier << (CPU_CT_xSIZE_SIZE(dsize) + 8);

		arm_dcache_align = arm_pdcache_line_size;

		arm_dcache_l2_assoc = CPU_CT_xSIZE_ASSOC(dsize) + multiplier - 2;
		arm_dcache_l2_linesize = CPU_CT_xSIZE_LEN(dsize) + 3;
		arm_dcache_l2_nsets = 6 + CPU_CT_xSIZE_SIZE(dsize) -
		    CPU_CT_xSIZE_ASSOC(dsize) - CPU_CT_xSIZE_LEN(dsize);

	out:
		arm_dcache_align_mask = arm_dcache_align - 1;
	}
}

static void
arm9_setup(void)
{

	get_cachetype_cp15();
	arm9_dcache_sets_inc = 1U << arm_dcache_l2_linesize;
	arm9_dcache_sets_max = (1U << (arm_dcache_l2_linesize +
	    arm_dcache_l2_nsets)) - arm9_dcache_sets_inc;
	arm9_dcache_index_inc = 1U << (32 - arm_dcache_l2_assoc);
	arm9_dcache_index_max = 0U - arm9_dcache_index_inc;
}

static void
armadaxp_idcache_wbinv_all(void)
{
	uint32_t feat;

	__asm __volatile("mrc p15, 0, %0, c0, c1, 0" : "=r" (feat));
	if (feat & ARM_PFR0_THUMBEE_MASK)
		armv7_idcache_wbinv_all();
	else
		armv6_idcache_wbinv_all();

}
#ifdef KZIP
static  unsigned char *orig_input, *i_input, *i_output;


static u_int memcnt;		/* Memory allocated: blocks */
static size_t memtot;		/* Memory allocated: bytes */
/*
 * Library functions required by inflate().
 */

#define MEMSIZ 0x8000

/*
 * Allocate memory block.
 */
unsigned char *
kzipmalloc(int size)
{
	void *ptr;
	static u_char mem[MEMSIZ];

	if (memtot + size > MEMSIZ)
		return NULL;
	ptr = mem + memtot;
	memtot += size;
	memcnt++;
	return ptr;
}

/*
 * Free allocated memory block.
 */
void
kzipfree(void *ptr)
{
	memcnt--;
	if (!memcnt)
		memtot = 0;
}

void
putstr(char *dummy)
{
}

static int
input(void *dummy)
{
	if ((size_t)(i_input - orig_input) >= KERNCOMPSIZE) {
		return (GZ_EOF);
	}
	return *i_input++;
}

static int
output(void *dummy, unsigned char *ptr, unsigned long len)
{


	memcpy(i_output, ptr, len);
	i_output += len;
	return (0);
}

static void *
inflate_kernel(void *kernel, void *startaddr)
{
	struct inflate infl;
	unsigned char slide[GZ_WSIZE];

	orig_input = kernel;
	memcnt = memtot = 0;
	i_input = (unsigned char *)kernel + GZ_HEAD;
	if (((char *)kernel)[3] & 0x18) {
		while (*i_input)
			i_input++;
		i_input++;
	}
	i_output = startaddr;
	bzero(&infl, sizeof(infl));
	infl.gz_input = input;
	infl.gz_output = output;
	infl.gz_slide = slide;
	inflate(&infl);
	return ((char *)(((vm_offset_t)i_output & ~3) + 4));
}

#endif

void *
load_kernel(unsigned int kstart, unsigned int curaddr,unsigned int func_end,
    int d)
{
	Elf32_Ehdr *eh;
	Elf32_Phdr phdr[64] /* XXX */, *php;
	Elf32_Shdr shdr[64] /* XXX */;
	int i,j;
	void *entry_point;
	int symtabindex = -1;
	int symstrindex = -1;
	vm_offset_t lastaddr = 0;
	Elf_Addr ssym = 0;
	Elf_Dyn *dp;

	eh = (Elf32_Ehdr *)kstart;
	ssym = 0;
	entry_point = (void*)eh->e_entry;
	memcpy(phdr, (void *)(kstart + eh->e_phoff ),
	    eh->e_phnum * sizeof(phdr[0]));

	/* Determine lastaddr. */
	for (i = 0; i < eh->e_phnum; i++) {
		if (lastaddr < (phdr[i].p_vaddr - KERNVIRTADDR + curaddr
		    + phdr[i].p_memsz))
			lastaddr = phdr[i].p_vaddr - KERNVIRTADDR +
			    curaddr + phdr[i].p_memsz;
	}

	/* Save the symbol tables, as there're about to be scratched. */
	memcpy(shdr, (void *)(kstart + eh->e_shoff),
	    sizeof(*shdr) * eh->e_shnum);
	if (eh->e_shnum * eh->e_shentsize != 0 &&
	    eh->e_shoff != 0) {
		for (i = 0; i < eh->e_shnum; i++) {
			if (shdr[i].sh_type == SHT_SYMTAB) {
				for (j = 0; j < eh->e_phnum; j++) {
					if (phdr[j].p_type == PT_LOAD &&
					    shdr[i].sh_offset >=
					    phdr[j].p_offset &&
					    (shdr[i].sh_offset +
					     shdr[i].sh_size <=
					     phdr[j].p_offset +
					     phdr[j].p_filesz)) {
						shdr[i].sh_offset = 0;
						shdr[i].sh_size = 0;
						j = eh->e_phnum;
					}
				}
				if (shdr[i].sh_offset != 0 &&
				    shdr[i].sh_size != 0) {
					symtabindex = i;
					symstrindex = shdr[i].sh_link;
				}
			}
		}
		func_end = roundup(func_end, sizeof(long));
		if (symtabindex >= 0 && symstrindex >= 0) {
			ssym = lastaddr;
			if (d) {
				memcpy((void *)func_end, (void *)(
				    shdr[symtabindex].sh_offset + kstart),
				    shdr[symtabindex].sh_size);
				memcpy((void *)(func_end +
				    shdr[symtabindex].sh_size),
				    (void *)(shdr[symstrindex].sh_offset +
				    kstart), shdr[symstrindex].sh_size);
			} else {
				lastaddr += shdr[symtabindex].sh_size;
				lastaddr = roundup(lastaddr,
				    sizeof(shdr[symtabindex].sh_size));
				lastaddr += sizeof(shdr[symstrindex].sh_size);
				lastaddr += shdr[symstrindex].sh_size;
				lastaddr = roundup(lastaddr,
				    sizeof(shdr[symstrindex].sh_size));
			}

		}
	}
	if (!d)
		return ((void *)lastaddr);

	j = eh->e_phnum;
	for (i = 0; i < j; i++) {
		volatile char c;

		if (phdr[i].p_type != PT_LOAD)
			continue;
		memcpy((void *)(phdr[i].p_vaddr - KERNVIRTADDR + curaddr),
		    (void*)(kstart + phdr[i].p_offset), phdr[i].p_filesz);
		/* Clean space from oversized segments, eg: bss. */
		if (phdr[i].p_filesz < phdr[i].p_memsz)
			bzero((void *)(phdr[i].p_vaddr - KERNVIRTADDR +
			    curaddr + phdr[i].p_filesz), phdr[i].p_memsz -
			    phdr[i].p_filesz);
	}
	/* Now grab the symbol tables. */
	if (symtabindex >= 0 && symstrindex >= 0) {
		*(Elf_Size *)lastaddr =
		    shdr[symtabindex].sh_size;
		lastaddr += sizeof(shdr[symtabindex].sh_size);
		memcpy((void*)lastaddr,
		    (void *)func_end,
		    shdr[symtabindex].sh_size);
		lastaddr += shdr[symtabindex].sh_size;
		lastaddr = roundup(lastaddr,
		    sizeof(shdr[symtabindex].sh_size));
		*(Elf_Size *)lastaddr =
		    shdr[symstrindex].sh_size;
		lastaddr += sizeof(shdr[symstrindex].sh_size);
		memcpy((void*)lastaddr,
		    (void*)(func_end +
			    shdr[symtabindex].sh_size),
		    shdr[symstrindex].sh_size);
		lastaddr += shdr[symstrindex].sh_size;
		lastaddr = roundup(lastaddr,
   		    sizeof(shdr[symstrindex].sh_size));
		*(Elf_Addr *)curaddr = MAGIC_TRAMP_NUMBER;
		*((Elf_Addr *)curaddr + 1) = ssym - curaddr + KERNVIRTADDR;
		*((Elf_Addr *)curaddr + 2) = lastaddr - curaddr + KERNVIRTADDR;
	} else
		*(Elf_Addr *)curaddr = 0;
	/* Invalidate the instruction cache. */
	__asm __volatile("mcr p15, 0, %0, c7, c5, 0\n"
	    		 "mcr p15, 0, %0, c7, c10, 4\n"
			 : : "r" (curaddr));
	__asm __volatile("mrc p15, 0, %0, c1, c0, 0\n"
	    "bic %0, %0, #1\n" /* MMU_ENABLE */
	    "mcr p15, 0, %0, c1, c0, 0\n"
	    : "=r" (ssym));
	/* Jump to the entry point. */
	((void(*)(void))(entry_point - KERNVIRTADDR + curaddr))();
	__asm __volatile(".globl func_end\n"
	    "func_end:");

	/* NOTREACHED */
	return NULL;
}

extern char func_end[];


#define PMAP_DOMAIN_KERNEL	0 /*
				    * Just define it instead of including the
				    * whole VM headers set.
				    */
int __hack;
static __inline void
setup_pagetables(unsigned int pt_addr, vm_paddr_t physstart, vm_paddr_t physend,
    int write_back)
{
	unsigned int *pd = (unsigned int *)pt_addr;
	vm_paddr_t addr;
	int domain = (DOMAIN_CLIENT << (PMAP_DOMAIN_KERNEL * 2)) | DOMAIN_CLIENT;
	int tmp;

	bzero(pd, L1_TABLE_SIZE);
	for (addr = physstart; addr < physend; addr += L1_S_SIZE) {
		pd[addr >> L1_S_SHIFT] = L1_TYPE_S|L1_S_C|L1_S_AP(AP_KRW)|
		    L1_S_DOM(PMAP_DOMAIN_KERNEL) | addr;
		if (write_back && 0)
			pd[addr >> L1_S_SHIFT] |= L1_S_B;
	}
	/* XXX: See below */
	if (0xfff00000 < physstart || 0xfff00000 > physend)
		pd[0xfff00000 >> L1_S_SHIFT] = L1_TYPE_S|L1_S_AP(AP_KRW)|
		    L1_S_DOM(PMAP_DOMAIN_KERNEL)|physstart;
	__asm __volatile("mcr p15, 0, %1, c2, c0, 0\n" /* set TTB */
	    		 "mcr p15, 0, %1, c8, c7, 0\n" /* Flush TTB */
			 "mcr p15, 0, %2, c3, c0, 0\n" /* Set DAR */
			 "mrc p15, 0, %0, c1, c0, 0\n"
			 "orr %0, %0, #1\n" /* MMU_ENABLE */
			 "mcr p15, 0, %0, c1, c0, 0\n"
			 "mrc p15, 0, %0, c2, c0, 0\n" /* CPWAIT */
			 "mov r0, r0\n"
			 "sub pc, pc, #4\n" :
			 "=r" (tmp) : "r" (pd), "r" (domain));

	/*
	 * XXX: This is the most stupid workaround I've ever wrote.
	 * For some reason, the KB9202 won't boot the kernel unless
	 * we access an address which is not in the
	 * 0x20000000 - 0x20ffffff range. I hope I'll understand
	 * what's going on later.
	 */
	__hack = *(volatile int *)0xfffff21c;
}

void
__start(void)
{
	void *curaddr;
	void *dst, *altdst;
	char *kernel = (char *)&kernel_start;
	int sp;
	int pt_addr;

	__asm __volatile("mov %0, pc"  :
	    "=r" (curaddr));
	curaddr = (void*)((unsigned int)curaddr & 0xfff00000);
#ifdef KZIP
	if (*kernel == 0x1f && kernel[1] == 0x8b) {
		pt_addr = (((int)&_end + KERNSIZE + 0x100) &
		    ~(L1_TABLE_SIZE - 1)) + L1_TABLE_SIZE;

#ifdef CPU_ARM9
		/* So that idcache_wbinv works; */
		if ((cpufunc_id() & 0x0000f000) == 0x00009000)
			arm9_setup();
#endif
		setup_pagetables(pt_addr, (vm_paddr_t)curaddr,
		    (vm_paddr_t)curaddr + 0x10000000, 1);
		/* Gzipped kernel */
		dst = inflate_kernel(kernel, &_end);
		kernel = (char *)&_end;
		altdst = 4 + load_kernel((unsigned int)kernel,
		    (unsigned int)curaddr,
		    (unsigned int)&func_end + 800 , 0);
		if (altdst > dst)
			dst = altdst;

		/*
		 * Disable MMU.  Otherwise, setup_pagetables call below
		 * might overwrite the L1 table we are currently using.
		 */
		cpu_idcache_wbinv_all();
		cpu_l2cache_wbinv_all();
		__asm __volatile("mrc p15, 0, %0, c1, c0, 0\n"
		  "bic %0, %0, #1\n" /* MMU_DISABLE */
		  "mcr p15, 0, %0, c1, c0, 0\n"
		  :"=r" (pt_addr));
	} else
#endif
		dst = 4 + load_kernel((unsigned int)&kernel_start,
	    (unsigned int)curaddr,
	    (unsigned int)&func_end, 0);
	dst = (void *)(((vm_offset_t)dst & ~3));
	pt_addr = ((unsigned int)dst &~(L1_TABLE_SIZE - 1)) + L1_TABLE_SIZE;
	setup_pagetables(pt_addr, (vm_paddr_t)curaddr,
	    (vm_paddr_t)curaddr + 0x10000000, 0);
	sp = pt_addr + L1_TABLE_SIZE + 8192;
	sp = sp &~3;
	dst = (void *)(sp + 4);
	memcpy((void *)dst, (void *)&load_kernel, (unsigned int)&func_end -
	    (unsigned int)&load_kernel + 800);
	do_call(dst, kernel, dst + (unsigned int)(&func_end) -
	    (unsigned int)(&load_kernel) + 800, sp);
}

#ifdef __ARM_EABI__
/* We need to provide these functions but never call them */
void __aeabi_unwind_cpp_pr0(void);
void __aeabi_unwind_cpp_pr1(void);
void __aeabi_unwind_cpp_pr2(void);

__strong_reference(__aeabi_unwind_cpp_pr0, __aeabi_unwind_cpp_pr1);
__strong_reference(__aeabi_unwind_cpp_pr0, __aeabi_unwind_cpp_pr2);
void
__aeabi_unwind_cpp_pr0(void)
{
}
#endif