arch/alpha/boot/bootpz.c - kernel/msm - Gitiles

 /*
  * arch/alpha/boot/bootpz.c
  *
  * Copyright (C) 1997 Jay Estabrook
  *
  * This file is used for creating a compressed BOOTP file for the
  * Linux/AXP kernel
  *
  * based significantly on the arch/alpha/boot/main.c of Linus Torvalds
  * and the decompression code from MILO.
  */
 #include <linux/kernel.h>
 #include <linux/string.h>
 #include <linux/utsrelease.h>
 #include <linux/mm.h>

 #include <asm/system.h>
 #include <asm/console.h>
 #include <asm/hwrpb.h>
 #include <asm/pgtable.h>
 #include <asm/io.h>

 #include <stdarg.h>

 #include "kzsize.h"

 /* FIXME FIXME FIXME */
 #define MALLOC_AREA_SIZE 0x200000 /* 2MB for now */
 /* FIXME FIXME FIXME */


 /*
   WARNING NOTE

   It is very possible that turning on additional messages may cause
   kernel image corruption due to stack usage to do the printing.

 */

 #undef DEBUG_CHECK_RANGE
 #undef DEBUG_ADDRESSES
 #undef DEBUG_LAST_STEPS

 extern unsigned long switch_to_osf_pal(unsigned long nr,
 	struct pcb_struct * pcb_va, struct pcb_struct * pcb_pa,
 	unsigned long *vptb);

 extern int decompress_kernel(void* destination, void *source,
 			     size_t ksize, size_t kzsize);

 extern void move_stack(unsigned long new_stack);

 struct hwrpb_struct *hwrpb = INIT_HWRPB;
 static struct pcb_struct pcb_va[1];

 /*
  * Find a physical address of a virtual object..
  *
  * This is easy using the virtual page table address.
  */
 #define VPTB	((unsigned long *) 0x200000000)

 static inline unsigned long
 find_pa(unsigned long address)
 {
 	unsigned long result;

 	result = VPTB[address >> 13];
 	result >>= 32;
 	result <<= 13;
 	result |= address & 0x1fff;
 	return result;
 }

 int
 check_range(unsigned long vstart, unsigned long vend,
 	    unsigned long kstart, unsigned long kend)
 {
 	unsigned long vaddr, kaddr;

 #ifdef DEBUG_CHECK_RANGE
 	srm_printk("check_range: V[0x%lx:0x%lx] K[0x%lx:0x%lx]\n",
 		   vstart, vend, kstart, kend);
 #endif
 	/* do some range checking for detecting an overlap... */
 	for (vaddr = vstart; vaddr <= vend; vaddr += PAGE_SIZE)
 	{
 		kaddr = (find_pa(vaddr) | PAGE_OFFSET);
 		if (kaddr >= kstart && kaddr <= kend)
 		{
 #ifdef DEBUG_CHECK_RANGE
 			srm_printk("OVERLAP: vaddr 0x%lx kaddr 0x%lx"
 				   " [0x%lx:0x%lx]\n",
 				   vaddr, kaddr, kstart, kend);
 #endif
 			return 1;
 		}
 	}
 	return 0;
 }

 /*
  * This function moves into OSF/1 pal-code, and has a temporary
  * PCB for that. The kernel proper should replace this PCB with
  * the real one as soon as possible.
  *
  * The page table muckery in here depends on the fact that the boot
  * code has the L1 page table identity-map itself in the second PTE
  * in the L1 page table. Thus the L1-page is virtually addressable
  * itself (through three levels) at virtual address 0x200802000.
  */

 #define L1	((unsigned long *) 0x200802000)

 void
 pal_init(void)
 {
 	unsigned long i, rev;
 	struct percpu_struct * percpu;
 	struct pcb_struct * pcb_pa;

 	/* Create the dummy PCB.  */
 	pcb_va->ksp = 0;
 	pcb_va->usp = 0;
 	pcb_va->ptbr = L1[1] >> 32;
 	pcb_va->asn = 0;
 	pcb_va->pcc = 0;
 	pcb_va->unique = 0;
 	pcb_va->flags = 1;
 	pcb_va->res1 = 0;
 	pcb_va->res2 = 0;
 	pcb_pa = (struct pcb_struct *)find_pa((unsigned long)pcb_va);

 	/*
 	 * a0 = 2 (OSF)
 	 * a1 = return address, but we give the asm the vaddr of the PCB
 	 * a2 = physical addr of PCB
 	 * a3 = new virtual page table pointer
 	 * a4 = KSP (but the asm sets it)
 	 */
 	srm_printk("Switching to OSF PAL-code... ");

 	i = switch_to_osf_pal(2, pcb_va, pcb_pa, VPTB);
 	if (i) {
 		srm_printk("failed, code %ld\n", i);
 		__halt();
 	}

 	percpu = (struct percpu_struct *)
 		(INIT_HWRPB->processor_offset + (unsigned long) INIT_HWRPB);
 	rev = percpu->pal_revision = percpu->palcode_avail[2];

 	srm_printk("OK (rev %lx)\n", rev);

 	tbia(); /* do it directly in case we are SMP */
 }

 /*
  * Start the kernel.
  */
 static inline void
 runkernel(void)
 {
 	__asm__ __volatile__(
 		"bis %0,%0,$27\n\t"
 		"jmp ($27)"
 		: /* no outputs: it doesn't even return */
 		: "r" (START_ADDR));
 }

 /* Must record the SP (it is virtual) on entry, so we can make sure
    not to overwrite it during movement or decompression. */
 unsigned long SP_on_entry;

 /* Calculate the kernel image address based on the end of the BOOTP
    bootstrapper (ie this program).
 */
 extern char _end;
 #define KERNEL_ORIGIN \
 	((((unsigned long)&_end) + 511) & ~511)

 /* Round address to next higher page boundary. */
 #define NEXT_PAGE(a)	(((a) | (PAGE_SIZE - 1)) + 1)

 #ifdef INITRD_IMAGE_SIZE
 # define REAL_INITRD_SIZE INITRD_IMAGE_SIZE
 #else
 # define REAL_INITRD_SIZE 0
 #endif

 /* Defines from include/asm-alpha/system.h

 	BOOT_ADDR	Virtual address at which the consoles loads
 			the BOOTP image.

 	KERNEL_START    KSEG address at which the kernel is built to run,
 			which includes some initial data pages before the
 			code.

 	START_ADDR	KSEG address of the entry point of kernel code.

 	ZERO_PGE	KSEG address of page full of zeroes, but
 			upon entry to kerne cvan be expected
 			to hold the parameter list and possible
 			INTRD information.

    These are used in the local defines below.
 */


 /* Virtual addresses for the BOOTP image. Note that this includes the
    bootstrapper code as well as the compressed kernel image, and
    possibly the INITRD image.

    Oh, and do NOT forget the STACK, which appears to be placed virtually
    beyond the end of the loaded image.
 */
 #define V_BOOT_IMAGE_START	BOOT_ADDR
 #define V_BOOT_IMAGE_END	SP_on_entry

 /* Virtual addresses for just the bootstrapper part of the BOOTP image. */
 #define V_BOOTSTRAPPER_START	BOOT_ADDR
 #define V_BOOTSTRAPPER_END	KERNEL_ORIGIN

 /* Virtual addresses for just the data part of the BOOTP
    image. This may also include the INITRD image, but always
    includes the STACK.
 */
 #define V_DATA_START		KERNEL_ORIGIN
 #define V_INITRD_START		(KERNEL_ORIGIN + KERNEL_Z_SIZE)
 #define V_INTRD_END		(V_INITRD_START + REAL_INITRD_SIZE)
 #define V_DATA_END	 	V_BOOT_IMAGE_END

 /* KSEG addresses for the uncompressed kernel.

    Note that the end address includes workspace for the decompression.
    Note also that the DATA_START address is ZERO_PGE, to which we write
    just before jumping to the kernel image at START_ADDR.
  */
 #define K_KERNEL_DATA_START	ZERO_PGE
 #define K_KERNEL_IMAGE_START	START_ADDR
 #define K_KERNEL_IMAGE_END	(START_ADDR + KERNEL_SIZE)

 /* Define to where we may have to decompress the kernel image, before
    we move it to the final position, in case of overlap. This will be
    above the final position of the kernel.

    Regardless of overlap, we move the INITRD image to the end of this
    copy area, because there needs to be a buffer area after the kernel
    for "bootmem" anyway.
 */
 #define K_COPY_IMAGE_START	NEXT_PAGE(K_KERNEL_IMAGE_END)
 /* Reserve one page below INITRD for the new stack. */
 #define K_INITRD_START \
     NEXT_PAGE(K_COPY_IMAGE_START + KERNEL_SIZE + PAGE_SIZE)
 #define K_COPY_IMAGE_END \
     (K_INITRD_START + REAL_INITRD_SIZE + MALLOC_AREA_SIZE)
 #define K_COPY_IMAGE_SIZE \
     NEXT_PAGE(K_COPY_IMAGE_END - K_COPY_IMAGE_START)

 void
 start_kernel(void)
 {
 	int must_move = 0;

 	/* Initialize these for the decompression-in-place situation,
 	   which is the smallest amount of work and most likely to
 	   occur when using the normal START_ADDR of the kernel
 	   (currently set to 16MB, to clear all console code.
 	*/
 	unsigned long uncompressed_image_start = K_KERNEL_IMAGE_START;
 	unsigned long uncompressed_image_end = K_KERNEL_IMAGE_END;

 	unsigned long initrd_image_start = K_INITRD_START;

 	/*
 	 * Note that this crufty stuff with static and envval
 	 * and envbuf is because:
 	 *
 	 * 1. Frequently, the stack is short, and we don't want to overrun;
 	 * 2. Frequently the stack is where we are going to copy the kernel to;
 	 * 3. A certain SRM console required the GET_ENV output to stack.
 	 *    ??? A comment in the aboot sources indicates that the GET_ENV
 	 *    destination must be quadword aligned.  Might this explain the
 	 *    behaviour, rather than requiring output to the stack, which
 	 *    seems rather far-fetched.
 	 */
 	static long nbytes;
 	static char envval[256] __attribute__((aligned(8)));
 	register unsigned long asm_sp asm("30");

 	SP_on_entry = asm_sp;

 	srm_printk("Linux/Alpha BOOTPZ Loader for Linux " UTS_RELEASE "\n");

 	/* Validity check the HWRPB. */
 	if (INIT_HWRPB->pagesize != 8192) {
 		srm_printk("Expected 8kB pages, got %ldkB\n",
 		           INIT_HWRPB->pagesize >> 10);
 		return;
 	}
 	if (INIT_HWRPB->vptb != (unsigned long) VPTB) {
 		srm_printk("Expected vptb at %p, got %p\n",
 			   VPTB, (void *)INIT_HWRPB->vptb);
 		return;
 	}

 	/* PALcode (re)initialization. */
 	pal_init();

 	/* Get the parameter list from the console environment variable. */
 	nbytes = callback_getenv(ENV_BOOTED_OSFLAGS, envval, sizeof(envval));
 	if (nbytes < 0 || nbytes >= sizeof(envval)) {
 		nbytes = 0;
 	}
 	envval[nbytes] = '\0';

 #ifdef DEBUG_ADDRESSES
 	srm_printk("START_ADDR 0x%lx\n", START_ADDR);
 	srm_printk("KERNEL_ORIGIN 0x%lx\n", KERNEL_ORIGIN);
 	srm_printk("KERNEL_SIZE 0x%x\n", KERNEL_SIZE);
 	srm_printk("KERNEL_Z_SIZE 0x%x\n", KERNEL_Z_SIZE);
 #endif

 	/* Since all the SRM consoles load the BOOTP image at virtual
 	 * 0x20000000, we have to ensure that the physical memory
 	 * pages occupied by that image do NOT overlap the physical
 	 * address range where the kernel wants to be run.  This
 	 * causes real problems when attempting to cdecompress the
 	 * former into the latter... :-(
 	 *
 	 * So, we may have to decompress/move the kernel/INITRD image
 	 * virtual-to-physical someplace else first before moving
 	 * kernel /INITRD to their final resting places... ;-}
 	 *
 	 * Sigh...
 	 */

 	/* First, check to see if the range of addresses occupied by
 	   the bootstrapper part of the BOOTP image include any of the
 	   physical pages into which the kernel will be placed for
 	   execution.

 	   We only need check on the final kernel image range, since we
 	   will put the INITRD someplace that we can be sure is not
 	   in conflict.
 	 */
 	if (check_range(V_BOOTSTRAPPER_START, V_BOOTSTRAPPER_END,
 			K_KERNEL_DATA_START, K_KERNEL_IMAGE_END))
 	{
 		srm_printk("FATAL ERROR: overlap of bootstrapper code\n");
 		__halt();
 	}

 	/* Next, check to see if the range of addresses occupied by
 	   the compressed kernel/INITRD/stack portion of the BOOTP
 	   image include any of the physical pages into which the
 	   decompressed kernel or the INITRD will be placed for
 	   execution.
 	 */
 	if (check_range(V_DATA_START, V_DATA_END,
 			K_KERNEL_IMAGE_START, K_COPY_IMAGE_END))
 	{
 #ifdef DEBUG_ADDRESSES
 		srm_printk("OVERLAP: cannot decompress in place\n");
 #endif
 		uncompressed_image_start = K_COPY_IMAGE_START;
 		uncompressed_image_end = K_COPY_IMAGE_END;
 		must_move = 1;

 		/* Finally, check to see if the range of addresses
 		   occupied by the compressed kernel/INITRD part of
 		   the BOOTP image include any of the physical pages
 		   into which that part is to be copied for
 		   decompression.
 		*/
 		while (check_range(V_DATA_START, V_DATA_END,
 				   uncompressed_image_start,
 				   uncompressed_image_end))
 		{
 #if 0
 			uncompressed_image_start += K_COPY_IMAGE_SIZE;
 			uncompressed_image_end += K_COPY_IMAGE_SIZE;
 			initrd_image_start += K_COPY_IMAGE_SIZE;
 #else
 			/* Keep as close as possible to end of BOOTP image. */
 			uncompressed_image_start += PAGE_SIZE;
 			uncompressed_image_end += PAGE_SIZE;
 			initrd_image_start += PAGE_SIZE;
 #endif
 		}
 	}

 	srm_printk("Starting to load the kernel with args '%s'\n", envval);

 #ifdef DEBUG_ADDRESSES
 	srm_printk("Decompressing the kernel...\n"
 		   "...from 0x%lx to 0x%lx size 0x%x\n",
 		   V_DATA_START,
 		   uncompressed_image_start,
 		   KERNEL_SIZE);
 #endif
         decompress_kernel((void *)uncompressed_image_start,
 			  (void *)V_DATA_START,
 			  KERNEL_SIZE, KERNEL_Z_SIZE);

 	/*
 	 * Now, move things to their final positions, if/as required.
 	 */

 #ifdef INITRD_IMAGE_SIZE

 	/* First, we always move the INITRD image, if present. */
 #ifdef DEBUG_ADDRESSES
 	srm_printk("Moving the INITRD image...\n"
 		   " from 0x%lx to 0x%lx size 0x%x\n",
 		   V_INITRD_START,
 		   initrd_image_start,
 		   INITRD_IMAGE_SIZE);
 #endif
 	memcpy((void *)initrd_image_start, (void *)V_INITRD_START,
 	       INITRD_IMAGE_SIZE);

 #endif /* INITRD_IMAGE_SIZE */

 	/* Next, we may have to move the uncompressed kernel to the
 	   final destination.
 	 */
 	if (must_move) {
 #ifdef DEBUG_ADDRESSES
 		srm_printk("Moving the uncompressed kernel...\n"
 			   "...from 0x%lx to 0x%lx size 0x%x\n",
 			   uncompressed_image_start,
 			   K_KERNEL_IMAGE_START,
 			   (unsigned)KERNEL_SIZE);
 #endif
 		/*
 		 * Move the stack to a safe place to ensure it won't be
 		 * overwritten by kernel image.
 		 */
 		move_stack(initrd_image_start - PAGE_SIZE);

 		memcpy((void *)K_KERNEL_IMAGE_START,
 		       (void *)uncompressed_image_start, KERNEL_SIZE);
 	}

 	/* Clear the zero page, then move the argument list in. */
 #ifdef DEBUG_LAST_STEPS
 	srm_printk("Preparing ZERO_PGE...\n");
 #endif
 	memset((char*)ZERO_PGE, 0, PAGE_SIZE);
 	strcpy((char*)ZERO_PGE, envval);

 #ifdef INITRD_IMAGE_SIZE

 #ifdef DEBUG_LAST_STEPS
 	srm_printk("Preparing INITRD info...\n");
 #endif
 	/* Finally, set the INITRD paramenters for the kernel. */
 	((long *)(ZERO_PGE+256))[0] = initrd_image_start;
 	((long *)(ZERO_PGE+256))[1] = INITRD_IMAGE_SIZE;

 #endif /* INITRD_IMAGE_SIZE */

 #ifdef DEBUG_LAST_STEPS
 	srm_printk("Doing 'runkernel()'...\n");
 #endif
 	runkernel();
 }
	/*
	* arch/alpha/boot/bootpz.c
	*
	* Copyright (C) 1997 Jay Estabrook
	*
	* This file is used for creating a compressed BOOTP file for the
	* Linux/AXP kernel
	*
	* based significantly on the arch/alpha/boot/main.c of Linus Torvalds
	* and the decompression code from MILO.
	*/
	#include <linux/kernel.h>
	#include <linux/string.h>
	#include <linux/utsrelease.h>
	#include <linux/mm.h>

	#include <asm/system.h>
	#include <asm/console.h>
	#include <asm/hwrpb.h>
	#include <asm/pgtable.h>
	#include <asm/io.h>

	#include <stdarg.h>

	#include "kzsize.h"

	/* FIXME FIXME FIXME */
	#define MALLOC_AREA_SIZE 0x200000 /* 2MB for now */
	/* FIXME FIXME FIXME */


	/*
	WARNING NOTE

	It is very possible that turning on additional messages may cause
	kernel image corruption due to stack usage to do the printing.

	*/

	#undef DEBUG_CHECK_RANGE
	#undef DEBUG_ADDRESSES
	#undef DEBUG_LAST_STEPS

	extern unsigned long switch_to_osf_pal(unsigned long nr,
	struct pcb_struct * pcb_va, struct pcb_struct * pcb_pa,
	unsigned long *vptb);

	extern int decompress_kernel(void* destination, void *source,
	size_t ksize, size_t kzsize);

	extern void move_stack(unsigned long new_stack);

	struct hwrpb_struct *hwrpb = INIT_HWRPB;
	static struct pcb_struct pcb_va[1];

	/*
	* Find a physical address of a virtual object..
	*
	* This is easy using the virtual page table address.
	*/
	#define VPTB ((unsigned long *) 0x200000000)

	static inline unsigned long
	find_pa(unsigned long address)
	{
	unsigned long result;

	result = VPTB[address >> 13];
	result >>= 32;
	result <<= 13;
	result \|= address & 0x1fff;
	return result;
	}

	int
	check_range(unsigned long vstart, unsigned long vend,
	unsigned long kstart, unsigned long kend)
	{
	unsigned long vaddr, kaddr;

	#ifdef DEBUG_CHECK_RANGE
	srm_printk("check_range: V[0x%lx:0x%lx] K[0x%lx:0x%lx]\n",
	vstart, vend, kstart, kend);
	#endif
	/* do some range checking for detecting an overlap... */
	for (vaddr = vstart; vaddr <= vend; vaddr += PAGE_SIZE)
	{
	kaddr = (find_pa(vaddr) \| PAGE_OFFSET);
	if (kaddr >= kstart && kaddr <= kend)
	{
	#ifdef DEBUG_CHECK_RANGE
	srm_printk("OVERLAP: vaddr 0x%lx kaddr 0x%lx"
	" [0x%lx:0x%lx]\n",
	vaddr, kaddr, kstart, kend);
	#endif
	return 1;
	}
	}
	return 0;
	}

	/*
	* This function moves into OSF/1 pal-code, and has a temporary
	* PCB for that. The kernel proper should replace this PCB with
	* the real one as soon as possible.
	*
	* The page table muckery in here depends on the fact that the boot
	* code has the L1 page table identity-map itself in the second PTE
	* in the L1 page table. Thus the L1-page is virtually addressable
	* itself (through three levels) at virtual address 0x200802000.
	*/

	#define L1 ((unsigned long *) 0x200802000)

	void
	pal_init(void)
	{
	unsigned long i, rev;
	struct percpu_struct * percpu;
	struct pcb_struct * pcb_pa;

	/* Create the dummy PCB. */
	pcb_va->ksp = 0;
	pcb_va->usp = 0;
	pcb_va->ptbr = L1[1] >> 32;
	pcb_va->asn = 0;
	pcb_va->pcc = 0;
	pcb_va->unique = 0;
	pcb_va->flags = 1;
	pcb_va->res1 = 0;
	pcb_va->res2 = 0;
	pcb_pa = (struct pcb_struct *)find_pa((unsigned long)pcb_va);

	/*
	* a0 = 2 (OSF)
	* a1 = return address, but we give the asm the vaddr of the PCB
	* a2 = physical addr of PCB
	* a3 = new virtual page table pointer
	* a4 = KSP (but the asm sets it)
	*/
	srm_printk("Switching to OSF PAL-code... ");

	i = switch_to_osf_pal(2, pcb_va, pcb_pa, VPTB);
	if (i) {
	srm_printk("failed, code %ld\n", i);
	__halt();
	}

	percpu = (struct percpu_struct *)
	(INIT_HWRPB->processor_offset + (unsigned long) INIT_HWRPB);
	rev = percpu->pal_revision = percpu->palcode_avail[2];

	srm_printk("OK (rev %lx)\n", rev);

	tbia(); /* do it directly in case we are SMP */
	}

	/*
	* Start the kernel.
	*/
	static inline void
	runkernel(void)
	{
	__asm__ __volatile__(
	"bis %0,%0,$27\n\t"
	"jmp ($27)"
	: /* no outputs: it doesn't even return */
	: "r" (START_ADDR));
	}

	/* Must record the SP (it is virtual) on entry, so we can make sure
	not to overwrite it during movement or decompression. */
	unsigned long SP_on_entry;

	/* Calculate the kernel image address based on the end of the BOOTP
	bootstrapper (ie this program).
	*/
	extern char _end;
	#define KERNEL_ORIGIN \
	((((unsigned long)&_end) + 511) & ~511)

	/* Round address to next higher page boundary. */
	#define NEXT_PAGE(a) (((a) \| (PAGE_SIZE - 1)) + 1)

	#ifdef INITRD_IMAGE_SIZE
	# define REAL_INITRD_SIZE INITRD_IMAGE_SIZE
	#else
	# define REAL_INITRD_SIZE 0
	#endif

	/* Defines from include/asm-alpha/system.h

	BOOT_ADDR Virtual address at which the consoles loads
	the BOOTP image.

	KERNEL_START KSEG address at which the kernel is built to run,
	which includes some initial data pages before the
	code.

	START_ADDR KSEG address of the entry point of kernel code.

	ZERO_PGE KSEG address of page full of zeroes, but
	upon entry to kerne cvan be expected
	to hold the parameter list and possible
	INTRD information.

	These are used in the local defines below.
	*/


	/* Virtual addresses for the BOOTP image. Note that this includes the
	bootstrapper code as well as the compressed kernel image, and
	possibly the INITRD image.

	Oh, and do NOT forget the STACK, which appears to be placed virtually
	beyond the end of the loaded image.
	*/
	#define V_BOOT_IMAGE_START BOOT_ADDR
	#define V_BOOT_IMAGE_END SP_on_entry

	/* Virtual addresses for just the bootstrapper part of the BOOTP image. */
	#define V_BOOTSTRAPPER_START BOOT_ADDR
	#define V_BOOTSTRAPPER_END KERNEL_ORIGIN

	/* Virtual addresses for just the data part of the BOOTP
	image. This may also include the INITRD image, but always
	includes the STACK.
	*/
	#define V_DATA_START KERNEL_ORIGIN
	#define V_INITRD_START (KERNEL_ORIGIN + KERNEL_Z_SIZE)
	#define V_INTRD_END (V_INITRD_START + REAL_INITRD_SIZE)
	#define V_DATA_END V_BOOT_IMAGE_END

	/* KSEG addresses for the uncompressed kernel.

	Note that the end address includes workspace for the decompression.
	Note also that the DATA_START address is ZERO_PGE, to which we write
	just before jumping to the kernel image at START_ADDR.
	*/
	#define K_KERNEL_DATA_START ZERO_PGE
	#define K_KERNEL_IMAGE_START START_ADDR
	#define K_KERNEL_IMAGE_END (START_ADDR + KERNEL_SIZE)

	/* Define to where we may have to decompress the kernel image, before
	we move it to the final position, in case of overlap. This will be
	above the final position of the kernel.

	Regardless of overlap, we move the INITRD image to the end of this
	copy area, because there needs to be a buffer area after the kernel
	for "bootmem" anyway.
	*/
	#define K_COPY_IMAGE_START NEXT_PAGE(K_KERNEL_IMAGE_END)
	/* Reserve one page below INITRD for the new stack. */
	#define K_INITRD_START \
	NEXT_PAGE(K_COPY_IMAGE_START + KERNEL_SIZE + PAGE_SIZE)
	#define K_COPY_IMAGE_END \
	(K_INITRD_START + REAL_INITRD_SIZE + MALLOC_AREA_SIZE)
	#define K_COPY_IMAGE_SIZE \
	NEXT_PAGE(K_COPY_IMAGE_END - K_COPY_IMAGE_START)

	void
	start_kernel(void)
	{
	int must_move = 0;

	/* Initialize these for the decompression-in-place situation,
	which is the smallest amount of work and most likely to
	occur when using the normal START_ADDR of the kernel
	(currently set to 16MB, to clear all console code.
	*/
	unsigned long uncompressed_image_start = K_KERNEL_IMAGE_START;
	unsigned long uncompressed_image_end = K_KERNEL_IMAGE_END;

	unsigned long initrd_image_start = K_INITRD_START;

	/*
	* Note that this crufty stuff with static and envval
	* and envbuf is because:
	*
	* 1. Frequently, the stack is short, and we don't want to overrun;
	* 2. Frequently the stack is where we are going to copy the kernel to;
	* 3. A certain SRM console required the GET_ENV output to stack.
	* ??? A comment in the aboot sources indicates that the GET_ENV
	* destination must be quadword aligned. Might this explain the
	* behaviour, rather than requiring output to the stack, which
	* seems rather far-fetched.
	*/
	static long nbytes;
	static char envval[256] __attribute__((aligned(8)));
	register unsigned long asm_sp asm("30");

	SP_on_entry = asm_sp;

	srm_printk("Linux/Alpha BOOTPZ Loader for Linux " UTS_RELEASE "\n");

	/* Validity check the HWRPB. */
	if (INIT_HWRPB->pagesize != 8192) {
	srm_printk("Expected 8kB pages, got %ldkB\n",
	INIT_HWRPB->pagesize >> 10);
	return;
	}
	if (INIT_HWRPB->vptb != (unsigned long) VPTB) {
	srm_printk("Expected vptb at %p, got %p\n",
	VPTB, (void *)INIT_HWRPB->vptb);
	return;
	}

	/* PALcode (re)initialization. */
	pal_init();

	/* Get the parameter list from the console environment variable. */
	nbytes = callback_getenv(ENV_BOOTED_OSFLAGS, envval, sizeof(envval));
	if (nbytes < 0 \|\| nbytes >= sizeof(envval)) {
	nbytes = 0;
	}
	envval[nbytes] = '\0';

	#ifdef DEBUG_ADDRESSES
	srm_printk("START_ADDR 0x%lx\n", START_ADDR);
	srm_printk("KERNEL_ORIGIN 0x%lx\n", KERNEL_ORIGIN);
	srm_printk("KERNEL_SIZE 0x%x\n", KERNEL_SIZE);
	srm_printk("KERNEL_Z_SIZE 0x%x\n", KERNEL_Z_SIZE);
	#endif

	/* Since all the SRM consoles load the BOOTP image at virtual
	* 0x20000000, we have to ensure that the physical memory
	* pages occupied by that image do NOT overlap the physical
	* address range where the kernel wants to be run. This
	* causes real problems when attempting to cdecompress the
	* former into the latter... :-(
	*
	* So, we may have to decompress/move the kernel/INITRD image
	* virtual-to-physical someplace else first before moving
	* kernel /INITRD to their final resting places... ;-}
	*
	* Sigh...
	*/

	/* First, check to see if the range of addresses occupied by
	the bootstrapper part of the BOOTP image include any of the
	physical pages into which the kernel will be placed for
	execution.

	We only need check on the final kernel image range, since we
	will put the INITRD someplace that we can be sure is not
	in conflict.
	*/
	if (check_range(V_BOOTSTRAPPER_START, V_BOOTSTRAPPER_END,
	K_KERNEL_DATA_START, K_KERNEL_IMAGE_END))
	{
	srm_printk("FATAL ERROR: overlap of bootstrapper code\n");
	__halt();
	}

	/* Next, check to see if the range of addresses occupied by
	the compressed kernel/INITRD/stack portion of the BOOTP
	image include any of the physical pages into which the
	decompressed kernel or the INITRD will be placed for
	execution.
	*/
	if (check_range(V_DATA_START, V_DATA_END,
	K_KERNEL_IMAGE_START, K_COPY_IMAGE_END))
	{
	#ifdef DEBUG_ADDRESSES
	srm_printk("OVERLAP: cannot decompress in place\n");
	#endif
	uncompressed_image_start = K_COPY_IMAGE_START;
	uncompressed_image_end = K_COPY_IMAGE_END;
	must_move = 1;

	/* Finally, check to see if the range of addresses
	occupied by the compressed kernel/INITRD part of
	the BOOTP image include any of the physical pages
	into which that part is to be copied for
	decompression.
	*/
	while (check_range(V_DATA_START, V_DATA_END,
	uncompressed_image_start,
	uncompressed_image_end))
	{
	#if 0
	uncompressed_image_start += K_COPY_IMAGE_SIZE;
	uncompressed_image_end += K_COPY_IMAGE_SIZE;
	initrd_image_start += K_COPY_IMAGE_SIZE;
	#else
	/* Keep as close as possible to end of BOOTP image. */
	uncompressed_image_start += PAGE_SIZE;
	uncompressed_image_end += PAGE_SIZE;
	initrd_image_start += PAGE_SIZE;
	#endif
	}
	}

	srm_printk("Starting to load the kernel with args '%s'\n", envval);

	#ifdef DEBUG_ADDRESSES
	srm_printk("Decompressing the kernel...\n"
	"...from 0x%lx to 0x%lx size 0x%x\n",
	V_DATA_START,
	uncompressed_image_start,
	KERNEL_SIZE);
	#endif
	decompress_kernel((void *)uncompressed_image_start,
	(void *)V_DATA_START,
	KERNEL_SIZE, KERNEL_Z_SIZE);

	/*
	* Now, move things to their final positions, if/as required.
	*/

	#ifdef INITRD_IMAGE_SIZE

	/* First, we always move the INITRD image, if present. */
	#ifdef DEBUG_ADDRESSES
	srm_printk("Moving the INITRD image...\n"
	" from 0x%lx to 0x%lx size 0x%x\n",
	V_INITRD_START,
	initrd_image_start,
	INITRD_IMAGE_SIZE);
	#endif
	memcpy((void )initrd_image_start, (void )V_INITRD_START,
	INITRD_IMAGE_SIZE);

	#endif /* INITRD_IMAGE_SIZE */

	/* Next, we may have to move the uncompressed kernel to the
	final destination.
	*/
	if (must_move) {
	#ifdef DEBUG_ADDRESSES
	srm_printk("Moving the uncompressed kernel...\n"
	"...from 0x%lx to 0x%lx size 0x%x\n",
	uncompressed_image_start,
	K_KERNEL_IMAGE_START,
	(unsigned)KERNEL_SIZE);
	#endif
	/*
	* Move the stack to a safe place to ensure it won't be
	* overwritten by kernel image.
	*/
	move_stack(initrd_image_start - PAGE_SIZE);

	memcpy((void *)K_KERNEL_IMAGE_START,
	(void *)uncompressed_image_start, KERNEL_SIZE);
	}

	/* Clear the zero page, then move the argument list in. */
	#ifdef DEBUG_LAST_STEPS
	srm_printk("Preparing ZERO_PGE...\n");
	#endif
	memset((char*)ZERO_PGE, 0, PAGE_SIZE);
	strcpy((char*)ZERO_PGE, envval);

	#ifdef INITRD_IMAGE_SIZE

	#ifdef DEBUG_LAST_STEPS
	srm_printk("Preparing INITRD info...\n");
	#endif
	/* Finally, set the INITRD paramenters for the kernel. */
	((long *)(ZERO_PGE+256))[0] = initrd_image_start;
	((long *)(ZERO_PGE+256))[1] = INITRD_IMAGE_SIZE;

	#endif /* INITRD_IMAGE_SIZE */

	#ifdef DEBUG_LAST_STEPS
	srm_printk("Doing 'runkernel()'...\n");
	#endif
	runkernel();
	}