initrd.h File Reference

Initial ramdisk (initrd) reshuffling. More...

#include <stdint.h>
#include <ipxe/memmap.h>

Go to the source code of this file.

Macros
#define	INITRD_ALIGN   4096
	Initial ramdisk chunk alignment. More...

Functions
	FILE_LICENCE (GPL2_OR_LATER_OR_UBDL)
void	initrd_reshuffle (void)
	Reshuffle initrds into desired order at top of memory. More...
int	initrd_region (size_t len, struct memmap_region *region)
	Calculate post-reshuffle initrd load region. More...
size_t	initrd_load_all (void *address)
	Load all initrds. More...
static size_t	initrd_align (size_t len)
	Align initrd length. More...
static size_t	initrd_len (void)
	Get required length for initrds. More...

Detailed Description

Initial ramdisk (initrd) reshuffling.

Definition in file initrd.h.

Macro Definition Documentation

INITRD_ALIGN

#define INITRD_ALIGN   4096

Initial ramdisk chunk alignment.

Definition at line 16 of file initrd.h.

Function Documentation

FILE_LICENCE()

FILE_LICENCE

(

GPL2_OR_LATER_OR_UBDL

)

initrd_reshuffle()

void initrd_reshuffle

(

void

)

Reshuffle initrds into desired order at top of memory.

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.

Definition at line 229 of file initrd.c.

                               {
        physaddr_t start;
        physaddr_t end;

        /* Calculate limits of reshuffle region */
        start = uheap_limit;
        end = ( initrd_end ? initrd_end : uheap_end );

        /* Debug */
        initrd_dump();

        /* Squash initrds as high as possible in memory */
        initrd_squash_high ( start, end );

        /* Bubble-sort initrds into desired order */
        while ( initrd_swap_any ( start, end ) ) {}

        /* Debug */
        initrd_dump();
}

References end, initrd_dump(), initrd_end, initrd_squash_high(), initrd_swap_any(), start, uheap_end, and uheap_limit.

Referenced by bzimage_load_initrds(), and lkrn_exec().

initrd_region()

int initrd_region	(	size_t	len,
		struct memmap_region *	region
	)

Calculate post-reshuffle initrd load region.

Parameters

len	Length of initrds (from initrd_len())
region	Region descriptor to fill in

Return values

rc	Return status code

If successful, then any suitably aligned range within the region may be used as the load address after reshuffling. The caller does not need to call prep_segment() for a range in this region. (Calling prep_segment() would probably fail, since prior to reshuffling the region is still in use by the external heap.)

Definition at line 354 of file initrd.c.

                                                               {
        physaddr_t min;
        size_t available;

        /* Calculate limits of available space for initrds */
        min = uheap_limit;
        available = ( ( initrd_end ? initrd_end : uheap_end ) - min );
        if ( available < len )
                return -ENOSPC;
        DBGC ( &images, "INITRD post-reshuffle region is [%#08lx,%#08lx)\n",
               min, ( min + available ) );

        /* Populate region descriptor */
        region->min = min;
        region->max = ( min + available - 1 );
        region->flags = MEMMAP_FL_MEMORY;
        region->name = "initrd";

        return 0;
}

References DBGC, ENOSPC, memmap_region::flags, images, initrd_end, len, memmap_region::max, MEMMAP_FL_MEMORY, min, memmap_region::min, memmap_region::name, uheap_end, and uheap_limit.

Referenced by bzimage_check_initrds(), and lkrn_exec().

initrd_load_all()

size_t initrd_load_all

(

void *

address

)

Load all initrds.

Parameters

address

Load address, or NULL

Return values

len

Length

This function is called after the point of no return, when the external heap has been corrupted by reshuffling and there is no way to resume normal execution. The caller must have previously ensured that there is no way for installation to this address to fail.

Definition at line 317 of file initrd.c.

                                         {
        struct image *initrd;
        size_t len = 0;
        size_t pad_len;
        void *dest;

        /* Load all initrds */
        for_each_image ( initrd ) {

                /* Zero-pad to next INITRD_ALIGN boundary */
                pad_len = ( ( -len ) & ( INITRD_ALIGN - 1 ) );
                if ( address )
                        memset ( ( address + len ), 0, pad_len );
                len += pad_len;
                assert ( len == initrd_align ( len ) );

                /* Load initrd */
                dest = ( address ? ( address + len ) : NULL );
                len += initrd_load ( initrd, dest );
        }

        return len;
}

References address, assert(), dest, for_each_image, INITRD_ALIGN, initrd_align(), initrd_load(), len, memset(), NULL, and pad_len.

Referenced by bzimage_load_initrds(), initrd_len(), and lkrn_exec().

initrd_align()

static size_t initrd_align ( size_t  len )

inlinestatic

Align initrd length.

Parameters

len

Length

Return values

len	Aligned length

Definition at line 29 of file initrd.h.

                            {

        return ( ( len + INITRD_ALIGN - 1 ) & ~( INITRD_ALIGN - 1 ) );
}

References INITRD_ALIGN, and len.

Referenced by initrd_load_all(), initrd_squash_high(), initrd_swap(), initrd_swap_any(), and lkrn_exec().

initrd_len()

static size_t initrd_len ( void  )

inlinestatic

Get required length for initrds.

Return values

len	Required length

Definition at line 40 of file initrd.h.

                    {

        return initrd_load_all ( NULL );
}

References initrd_load_all(), and NULL.