src/arch/i386/transitions/librm_mgmt.c

   1 /*
   2  * librm: a library for interfacing to real-mode code
   3  *
   4  * Michael Brown <mbrown@fensystems.co.uk>
   5  *
   6  */
   7
   8 FILE_LICENCE ( GPL2_OR_LATER );
   9
  10 #include <stdint.h>
  11 #include <realmode.h>
  12
  13 /*
  14  * This file provides functions for managing librm.
  15  *
  16  */
  17
  18 /**
  19  * Allocate space on the real-mode stack and copy data there from a
  20  * user buffer
  21  *
  22  * @v data                      User buffer
  23  * @v size                      Size of stack data
  24  * @ret sp                      New value of real-mode stack pointer
  25  */
  26 uint16_t copy_user_to_rm_stack ( userptr_t data, size_t size ) {
  27         userptr_t rm_stack;
  28         rm_sp -= size;
  29         rm_stack = real_to_user ( rm_ss, rm_sp );
  30         memcpy_user ( rm_stack, 0, data, 0, size );
  31         return rm_sp;
  32 };
  33
  34 /**
  35  * Deallocate space on the real-mode stack, optionally copying back
  36  * data to a user buffer.
  37  *
  38  * @v data                      User buffer
  39  * @v size                      Size of stack data
  40  */
  41 void remove_user_from_rm_stack ( userptr_t data, size_t size ) {
  42         if ( data ) {
  43                 userptr_t rm_stack = real_to_user ( rm_ss, rm_sp );
  44                 memcpy_user ( rm_stack, 0, data, 0, size );
  45         }
  46         rm_sp += size;
  47 };
  48
  49 PROVIDE_UACCESS_INLINE ( librm, phys_to_user );
  50 PROVIDE_UACCESS_INLINE ( librm, user_to_phys );
  51 PROVIDE_UACCESS_INLINE ( librm, virt_to_user );
  52 PROVIDE_UACCESS_INLINE ( librm, user_to_virt );
  53 PROVIDE_UACCESS_INLINE ( librm, userptr_add );
  54 PROVIDE_UACCESS_INLINE ( librm, memcpy_user );
  55 PROVIDE_UACCESS_INLINE ( librm, memmove_user );
  56 PROVIDE_UACCESS_INLINE ( librm, memset_user );
  57 PROVIDE_UACCESS_INLINE ( librm, strlen_user );
  58 PROVIDE_UACCESS_INLINE ( librm, memchr_user );