--- /dev/null
+/*
+ * 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.
+ */
+
+FILE_LICENCE ( GPL2_OR_LATER );
+
+#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 ) = {
+ .startup = initrd_startup,
+};
Code Review / kvmfornfv.git / blobdiff