include/asm-nios2nommu/flat.h

   1 /*
   2  * include/asm-nios2nommu/flat.h -- uClinux bFLT relocations
   3  *
   4  *  Copyright (C) 2004,05  Microtronix Datacom Ltd
   5  *
   6  * This file is subject to the terms and conditions of the GNU General
   7  * Public License.  See the file COPYING in the main directory of this
   8  * archive for more details.
   9  *
  10  * Written by Wentao Xu <wentao@microtronix.com>
  11  */
  12
  13 #ifndef __NIOS2_FLAT_H__
  14 #define __NIOS2_FLAT_H__
  15
  16 #define flat_reloc_valid(reloc, size)   ((reloc) <= (size + 0x8000))
  17
  18 /* The stack is 64-bit aligned for Nios II, so (sp - 1) shall
  19  * be 64-bit aligned, where -1 is for argc
  20  */
  21 #define flat_stack_align(sp)            (sp = (unsigned long *)(((unsigned long)sp - 1) & (-8)))
  22
  23 /* The uClibc port for Nios II expects the argc is followed by argv and envp */
  24 #define flat_argvp_envp_on_stack()      1
  25
  26 #define flat_old_ram_flag(flags)        (flags)
  27
  28 /* We store the type of relocation in the top 4 bits of the `relval.' */
  29
  30 /* Convert a relocation entry into an address.  */
  31 static inline unsigned long
  32 flat_get_relocate_addr (unsigned long relval)
  33 {
  34         return relval & 0x0fffffff; /* Mask out top 4-bits */
  35 }
  36
  37 #define FLAT_NIOS2_RELOC_TYPE(relval) ((relval) >> 28)
  38
  39 #define FLAT_NIOS2_R_32                 0 /* Normal 32-bit reloc */
  40 #define FLAT_NIOS2_R_HI_LO              1 /* High 16-bits + low 16-bits field */
  41 #define FLAT_NIOS2_R_HIADJ_LO   2 /* High 16-bits adjust + low 16-bits field */
  42 #define FLAT_NIOS2_R_CALL26             4 /* Call imm26 */
  43
  44 /* Extract the address to be relocated from the symbol reference at rp;
  45  * relval is the raw relocation-table entry from which RP is derived.
  46  * rp shall always be 32-bit aligned
  47  */
  48 static inline unsigned long flat_get_addr_from_rp (unsigned long *rp,
  49                                                    unsigned long relval,
  50                                                    unsigned long flags)
  51 {
  52         switch (FLAT_NIOS2_RELOC_TYPE(relval))
  53         {
  54         case FLAT_NIOS2_R_32:
  55                 /* Simple 32-bit address. The loader expect it in bigger endian */
  56                 return htonl(*rp);
  57
  58         case FLAT_NIOS2_R_HI_LO:
  59                 /* get the two 16-bit immediate value from instructions, then
  60                  * construct a 32-bit value. Again the loader expect bigger endian
  61                  */
  62                 return htonl ((((rp[0] >> 6) & 0xFFFF) << 16 ) |
  63                                           ((rp[1] >> 6) & 0xFFFF));
  64
  65         case FLAT_NIOS2_R_HIADJ_LO:
  66                 {
  67                 /* get the two 16-bit immediate value from instructions, then
  68                  * construct a 32-bit value. Again the loader expect bigger endian
  69                  */
  70                  unsigned int low, high;
  71                  high = (rp[0] >> 6) & 0xFFFF;
  72                  low  = (rp[1] >> 6) & 0xFFFF;
  73
  74                  if ((low >> 15) & 1) high--;
  75
  76                  return htonl ((high << 16 ) | low );
  77                 }
  78         case FLAT_NIOS2_R_CALL26:
  79                 /* the 26-bit immediate value is actually 28-bit */
  80                 return htonl(((*rp) >> 6) << 2);
  81
  82         default:
  83                 return ~0;      /* bogus value */
  84         }
  85 }
  86
  87 /* Insert the address addr into the symbol reference at rp;
  88  * relval is the raw relocation-table entry from which rp is derived.
  89  * rp shall always be 32-bit aligned
  90  */
  91 static inline void flat_put_addr_at_rp (unsigned long *rp, unsigned long addr,
  92                                         unsigned long relval)
  93 {
  94         unsigned long exist_val;
  95         switch (FLAT_NIOS2_RELOC_TYPE (relval)) {
  96         case FLAT_NIOS2_R_32:
  97                 /* Simple 32-bit address.  */
  98                 *rp = addr;
  99                 break;
 100
 101         case FLAT_NIOS2_R_HI_LO:
 102                 exist_val = rp[0];
 103                 rp[0] = ((((exist_val >> 22) << 16) | (addr >> 16)) << 6) | (exist_val & 0x3F);
 104                 exist_val = rp[1];
 105                 rp[1] = ((((exist_val >> 22) << 16) | (addr & 0xFFFF)) << 6) | (exist_val & 0x3F);
 106                 break;
 107
 108         case FLAT_NIOS2_R_HIADJ_LO:
 109                 {
 110                 unsigned int high = (addr >> 16);
 111                 if ((addr >> 15) & 1)
 112                         high = (high + 1) & 0xFFFF;
 113                 exist_val = rp[0];
 114                 rp[0] = ((((exist_val >> 22) << 16) | high) << 6) | (exist_val & 0x3F);
 115                 exist_val = rp[1];
 116                 rp[1] = ((((exist_val >> 22) << 16) | (addr & 0xFFFF)) << 6) | (exist_val & 0x3F);
 117                 break;
 118                 }
 119         case FLAT_NIOS2_R_CALL26:
 120                 /* the opcode of CALL is 0, so just store the value */
 121                 *rp = ((addr >> 2) << 6);
 122                 break;
 123         }
 124 }
 125
 126 #endif /* __NIOS2_FLAT_H__ */