/*
* Copyright (C) 2012 Michael Brown <mbrown@fensystems.co.uk>.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License as
* published by the Free Software Foundation; either version 2 of the
* License, or (at your option) any later version.
*
* This program is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
* 02110-1301, USA.
*
* You can also choose to distribute this program under the terms of
* the Unmodified Binary Distribution Licence (as given in the file
* COPYING.UBDL), provided that you have satisfied its requirements.
*/
FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
#include <errno.h>
#include <initrd.h>
#include <ipxe/image.h>
#include <ipxe/uaccess.h>
#include <ipxe/init.h>
#include <ipxe/memblock.h>
/** @file
*
* Initial ramdisk (initrd) reshuffling
*
*/
/** Maximum address available for initrd */
userptr_t initrd_top;
/** Minimum address available for initrd */
userptr_t initrd_bottom;
/**
* Squash initrds as high as possible in memory
*
* @v top Highest possible address
* @ret used Lowest address used by initrds
*/
static userptr_t initrd_squash_high ( userptr_t top ) {
userptr_t current = top;
struct image *initrd;
struct image *highest;
size_t len;
/* Squash up any initrds already within or below the region */
while ( 1 ) {
/* Find the highest image not yet in its final position */
highest = NULL;
for_each_image ( initrd ) {
if ( ( userptr_sub ( initrd->data, current ) < 0 ) &&
( ( highest == NULL ) ||
( userptr_sub ( initrd->data,
highest->data ) > 0 ) ) ) {
highest = initrd;
}
}
if ( ! highest )
break;
/* Move this image to its final position */
len = ( ( highest->len + INITRD_ALIGN - 1 ) &
~( INITRD_ALIGN - 1 ) );
current = userptr_sub ( current, len );
DBGC ( &images, "INITRD squashing %s [%#08lx,%#08lx)->"
"[%#08lx,%#08lx)\n", highest->name,
user_to_phys ( highest->data, 0 ),
user_to_phys ( highest->data, highest->len ),
user_to_phys ( current, 0 ),
user_to_phys ( current, highest->len ) );
memmove_user ( current, 0, highest->data, 0, highest->len );
highest->data = current;
}
/* Copy any remaining initrds (e.g. embedded images) to the region */
for_each_image ( initrd ) {
if ( userptr_sub ( initrd->data, top ) >= 0 ) {
len = ( ( initrd->len + INITRD_ALIGN - 1 ) &
~( INITRD_ALIGN - 1 ) );
current = userptr_sub ( current, len );
DBGC ( &images, "INITRD copying %s [%#08lx,%#08lx)->"
"[%#08lx,%#08lx)\n", initrd->name,
user_to_phys ( initrd->data, 0 ),
user_to_phys ( initrd->data, initrd->len ),
user_to_phys ( current, 0 ),
user_to_phys ( current, initrd->len ) );
memcpy_user ( current, 0, initrd->data, 0,
initrd->len );
initrd->data = current;
}
}
return current;
}
/**
* Swap position of two adjacent initrds
*
* @v low Lower initrd
* @v high Higher initrd
* @v free Free space
* @v free_len Length of free space
*/
static void initrd_swap ( struct image *low, struct image *high,
userptr_t free, size_t free_len ) {
size_t len = 0;
size_t frag_len;
size_t new_len;
DBGC ( &images, "INITRD swapping %s [%#08lx,%#08lx)<->[%#08lx,%#08lx) "
"%s\n", low->name, user_to_phys ( low->data, 0 ),
user_to_phys ( low->data, low->len ),
user_to_phys ( high->data, 0 ),
user_to_phys ( high->data, high->len ), high->name );
/* Round down length of free space */
free_len &= ~( INITRD_ALIGN - 1 );
assert ( free_len > 0 );
/* Swap image data */
while ( len < high->len ) {
/* Calculate maximum fragment length */
frag_len = ( high->len - len );
if ( frag_len > free_len )
frag_len = free_len;
new_len = ( ( len + frag_len + INITRD_ALIGN - 1 ) &
~( INITRD_ALIGN - 1 ) );
/* Swap fragments */
memcpy_user ( free, 0, high->data, len, frag_len );
memmove_user ( low->data, new_len, low->data, len, low->len );
memcpy_user ( low->data, len, free, 0, frag_len );
len = new_len;
}
/* Adjust data pointers */
high->data = low->data;
low->data = userptr_add ( low->data, len );
}
/**
* Swap position of any two adjacent initrds not currently in the correct order
*
* @v free Free space
* @v free_len Length of free space
* @ret swapped A pair of initrds was swapped
*/
static int initrd_swap_any ( userptr_t free, size_t free_len ) {
struct image *low;
struct image *high;
size_t padded_len;
userptr_t adjacent;
/* Find any pair of initrds that can be swapped */
for_each_image ( low ) {
/* Calculate location of adjacent image (if any) */
padded_len = ( ( low->len + INITRD_ALIGN - 1 ) &
~( INITRD_ALIGN - 1 ) );
adjacent = userptr_add ( low->data, padded_len );
/* Search for adjacent image */
for_each_image ( high ) {
/* If we have found the adjacent image, swap and exit */
if ( high->data == adjacent ) {
initrd_swap ( low, high, free, free_len );
return 1;
}
/* Stop search if all remaining potential
* adjacent images are already in the correct
* order.
*/
if ( high == low )
break;
}
}
/* Nothing swapped */
return 0;
}
/**
* Dump initrd locations (for debug)
*
*/
static void initrd_dump ( void ) {
struct image *initrd;
/* Do nothing unless debugging is enabled */
if ( ! DBG_LOG )
return;
/* Dump initrd locations */
for_each_image ( initrd ) {
DBGC ( &images, "INITRD %s at [%#08lx,%#08lx)\n",
initrd->name, user_to_phys ( initrd->data, 0 ),
user_to_phys ( initrd->data, initrd->len ) );
DBGC2_MD5A ( &images, user_to_phys ( initrd->data, 0 ),
user_to_virt ( initrd->data, 0 ), initrd->len );
}
}
/**
* Reshuffle initrds into desired order at top of memory
*
* @v bottom Lowest address available for initrds
*
* After this function returns, the initrds have been rearranged in
* memory and the external heap structures will have been corrupted.
* Reshuffling must therefore take place immediately prior to jumping
* to the loaded OS kernel; no further execution within iPXE is
* permitted.
*/
void initrd_reshuffle ( userptr_t bottom ) {
userptr_t top;
userptr_t used;
userptr_t free;
size_t free_len;
/* Calculate limits of available space for initrds */
top = initrd_top;
if ( userptr_sub ( initrd_bottom, bottom ) > 0 )
bottom = initrd_bottom;
/* Debug */
DBGC ( &images, "INITRD region [%#08lx,%#08lx)\n",
user_to_phys ( bottom, 0 ), user_to_phys ( top, 0 ) );
initrd_dump();
/* Squash initrds as high as possible in memory */
used = initrd_squash_high ( top );
/* Calculate available free space */
free = bottom;
free_len = userptr_sub ( used, free );
/* Bubble-sort initrds into desired order */
while ( initrd_swap_any ( free, free_len ) ) {}
/* Debug */
initrd_dump();
}
/**
* Check that there is enough space to reshuffle initrds
*
* @v len Total length of initrds (including padding)
* @v bottom Lowest address available for initrds
* @ret rc Return status code
*/
int initrd_reshuffle_check ( size_t len, userptr_t bottom ) {
userptr_t top;
size_t available;
/* Calculate limits of available space for initrds */
top = initrd_top;
if ( userptr_sub ( initrd_bottom, bottom ) > 0 )
bottom = initrd_bottom;
available = userptr_sub ( top, bottom );
/* Allow for a sensible minimum amount of free space */
len += INITRD_MIN_FREE_LEN;
/* Check for available space */
return ( ( len < available ) ? 0 : -ENOBUFS );
}
/**
* initrd startup function
*
*/
static void initrd_startup ( void ) {
size_t len;
/* Record largest memory block available. Do this after any
* allocations made during driver startup (e.g. large host
* memory blocks for Infiniband devices, which may still be in
* use at the time of rearranging if a SAN device is hooked)
* but before any allocations for downloaded images (which we
* can safely reuse when rearranging).
*/
len = largest_memblock ( &initrd_bottom );
initrd_top = userptr_add ( initrd_bottom, len );
}
/** initrd startup function */
struct startup_fn startup_initrd __startup_fn ( STARTUP_LATE ) = {
.name = "initrd",
.startup = initrd_startup,
};
