efi_umalloc.c File Reference

iPXE user memory allocation API for EFI More...

#include <string.h>
#include <errno.h>
#include <assert.h>
#include <ipxe/uaccess.h>
#include <ipxe/umalloc.h>
#include <ipxe/efi/efi.h>

Go to the source code of this file.

Functions
	FILE_LICENCE (GPL2_OR_LATER_OR_UBDL)
	FILE_SECBOOT (PERMITTED)
static void *	efi_urealloc (void *old_ptr, size_t new_size)
	Reallocate external memory. More...
	PROVIDE_UMALLOC (efi, urealloc, efi_urealloc)

Detailed Description

iPXE user memory allocation API for EFI

Definition in file efi_umalloc.c.

Function Documentation

FILE_LICENCE()

FILE_LICENCE

(

GPL2_OR_LATER_OR_UBDL

)

FILE_SECBOOT()

FILE_SECBOOT

(

PERMITTED

)

efi_urealloc()

static void* efi_urealloc ( void *  old_ptr, size_t  new_size  )

static

Reallocate external memory.

Parameters

old_ptr	Memory previously allocated by umalloc(), or NULL
new_size	Requested size

Return values

new_ptr

Allocated memory, or NULL

Calling realloc() with a new size of zero is a valid way to free a memory block.

Definition at line 50 of file efi_umalloc.c.

                                                              {
        EFI_BOOT_SERVICES *bs = efi_systab->BootServices;
        EFI_PHYSICAL_ADDRESS phys_addr;
        unsigned int new_pages, old_pages;
        void *new_ptr = NOWHERE;
        size_t old_size;
        size_t *info;
        EFI_STATUS efirc;
        int rc;

        /* Allocate new memory if necessary.  If allocation fails,
         * return without touching the old block.
         */
        if ( new_size ) {
                new_pages = ( EFI_SIZE_TO_PAGES ( new_size ) + 1 );
                if ( ( efirc = bs->AllocatePages ( AllocateAnyPages,
                                                   EfiBootServicesData,
                                                   new_pages,
                                                   &phys_addr ) ) != 0 ) {
                        rc = -EEFI ( efirc );
                        DBG ( "EFI could not allocate %d pages: %s\n",
                              new_pages, strerror ( rc ) );
                        return NULL;
                }
                assert ( phys_addr != 0 );
                new_ptr = phys_to_virt ( phys_addr + EFI_PAGE_SIZE );
                info = ( new_ptr - EFI_PAGE_SIZE );
                *info = new_size;
                DBG ( "EFI allocated %d pages at %llx\n",
                      new_pages, phys_addr );
        }

        /* Copy across relevant part of the old data region (if any),
         * then free it.  Note that at this point either (a) new_ptr
         * is valid, or (b) new_size is 0; either way, the memcpy() is
         * valid.
         */
        if ( old_ptr && ( old_ptr != NOWHERE ) ) {
                info = ( old_ptr - EFI_PAGE_SIZE );
                old_size = *info;
                memcpy ( new_ptr, old_ptr,
                         ( (old_size < new_size) ? old_size : new_size ) );
                old_pages = ( EFI_SIZE_TO_PAGES ( old_size ) + 1 );
                phys_addr = virt_to_phys ( old_ptr - EFI_PAGE_SIZE );
                if ( ( efirc = bs->FreePages ( phys_addr, old_pages ) ) != 0 ){
                        rc = -EEFI ( efirc );
                        DBG ( "EFI could not free %d pages at %llx: %s\n",
                              old_pages, phys_addr, strerror ( rc ) );
                        /* Not fatal; we have leaked memory but successfully
                         * allocated (if asked to do so).
                         */
                }
                DBG ( "EFI freed %d pages at %llx\n", old_pages, phys_addr );
        }

        return new_ptr;
}

References AllocateAnyPages, EFI_BOOT_SERVICES::AllocatePages, assert(), EFI_SYSTEM_TABLE::BootServices, DBG, EEFI, EFI_PAGE_SIZE, EFI_SIZE_TO_PAGES, efi_systab, EfiBootServicesData, EFI_BOOT_SERVICES::FreePages, info, memcpy(), NOWHERE, NULL, rc, and strerror().

PROVIDE_UMALLOC()

PROVIDE_UMALLOC	(	efi	,
		urealloc	,
		efi_urealloc
	)