ld/emultempl/spu_ovl.S

   1 /* Overlay manager for SPU.
   2
   3    Copyright 2006, 2007 Free Software Foundation, Inc.
   4
   5    This file is part of GLD, the Gnu Linker.
   6
   7    GLD is free software; you can redistribute it and/or modify
   8    it under the terms of the GNU General Public License as published by
   9    the Free Software Foundation; either version 2, or (at your option)
  10    any later version.
  11
  12    GLD is distributed in the hope that it will be useful,
  13    but WITHOUT ANY WARRANTY; without even the implied warranty of
  14    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15    GNU General Public License for more details.
  16
  17    You should have received a copy of the GNU General Public License
  18    along with GLD; see the file COPYING.  If not, write to the Free
  19    Software Foundation, 51 Franklin Street - Fifth Floor, Boston, MA
  20    02110-1301, USA.  */
  21
  22 /**
  23  * MFC DMA defn's.
  24  */
  25 #define MFC_GET_CMD             0x40
  26 #define MFC_MAX_DMA_SIZE        0x4000
  27 #define MFC_TAG_UPDATE_ALL      2
  28 #define MFC_TAG_ID              0
  29
  30
  31 /**
  32  * Temporary register allocations.
  33  * These are saved/restored here.
  34  */
  35 #define tab             $75
  36 #define cgbits          $75
  37 #define add64           $75
  38 #define ealo            $75
  39 #define newmask         $75
  40 #define tagstat         $75
  41 #define bchn            $75
  42 #define rv1             $75
  43
  44 #define off             $76
  45 #define off64           $76
  46 #define maxsize         $76
  47 #define oldmask         $76
  48 #define sz              $76
  49 #define lnkr            $76
  50 #define rv2             $76
  51
  52 #define cur             $77
  53 #define cmp             $77
  54 #define buf             $77
  55 #define genwi           $77
  56 #define tagid           $77
  57 #define cmd             $77
  58 #define rv3             $77
  59
  60 #define cgshuf          $78
  61
  62 #define vma             $6
  63
  64 #define map             $7
  65 #define osize           $7
  66 #define cmp2            $7
  67
  68 #define ea64            $8
  69 #define retval          $8
  70
  71 #ifdef OVLY_IRQ_SAVE
  72 #define irqtmp          $8
  73 #define irq_stat        $9
  74 #endif
  75
  76         .extern         _ovly_table
  77         .extern         _ovly_buf_table
  78
  79         .text
  80         .align          4
  81 __rv_pattern:
  82         .word           0x00010203, 0x1c1d1e1f, 0x00010203, 0x10111213
  83 __cg_pattern:
  84         .word           0x04050607, 0x80808080, 0x80808080, 0x80808080
  85
  86 /**
  87  * __ovly_return - stub for returning from overlay functions.
  88  *
  89  * inputs:
  90  *      $lr     link register
  91  *
  92  * outputs:
  93  *      $78     old partition number, to be reloaded
  94  *      $79     return address in old partion number
  95  */
  96         .global         __ovly_return
  97         .type           __ovly_return, @function
  98
  99         .word           0
 100 __ovly_return:
 101         shlqbyi         $78, $lr, 4
 102         shlqbyi         $79, $lr, 8
 103         biz             $78, $79
 104         .size           __ovly_return, . - __ovly_return
 105
 106 /**
 107  * __ovly_load - copy an overlay partion to local store.
 108  *
 109  * inputs:
 110  *      $78     partition number to be loaded.
 111  *      $79     branch target in new partition.
 112  *      $lr     link register, containing return addr.
 113  *
 114  * outputs:
 115  *      $lr     new link register, returning through __ovly_return.
 116  *
 117  * Copy a new overlay partition into local store, or return
 118  * immediately if the partition is already resident.
 119  */
 120         .global         __ovly_load
 121         .type           __ovly_load, @function
 122
 123 __ovly_load:
 124 /* Save temporary registers to stack. */
 125         stqd            $6, -16($sp)
 126         stqd            $7, -32($sp)
 127         stqd            $8, -48($sp)
 128
 129 #ifdef OVLY_IRQ_SAVE
 130 /* Save irq state, then disable interrupts. */
 131         stqd            $9, -64($sp)
 132         ila             irqtmp, __ovly_irq_save
 133         rdch            irq_stat, $SPU_RdMachStat
 134         bid             irqtmp
 135 __ovly_irq_save:
 136 #endif
 137
 138 /* Set branch hint to overlay target. */
 139         hbr             __ovly_load_ret, $79
 140
 141 /* Get caller's overlay index by back chaining through stack frames.
 142  * Loop until end of stack (back chain all-zeros) or
 143  * encountered a link register we set here. */
 144         lqd             bchn, 0($sp)
 145         ila             retval, __ovly_return
 146
 147 __ovly_backchain_loop:
 148         lqd             lnkr, 16(bchn)
 149         lqd             bchn, 0(bchn)
 150         ceq             cmp, lnkr, retval
 151         ceqi            cmp2, bchn, 0
 152         or              cmp, cmp, cmp2
 153         brz             cmp, __ovly_backchain_loop
 154
 155 /* If we reached the zero back-chain, then lnkr is bogus.  Clear the
 156  * part of lnkr that we use later (slot 3). */
 157         rotqbyi         cmp2, cmp2, 4
 158         andc            lnkr, lnkr, cmp2
 159
 160 /* Set lr = {__ovly_return, prev ovl ndx, caller return adr, callee ovl ndx}. */
 161         lqd             rv1, (__rv_pattern-__ovly_return+4)(retval)
 162         shufb           rv2, retval, lnkr, rv1
 163         shufb           rv3, $lr, $78, rv1
 164         fsmbi           rv1, 0xff
 165         selb            $lr, rv2, rv3, rv1
 166
 167 /* Branch to $79 if non-overlay */
 168         brz             $78, __ovly_load_restore
 169
 170 /* Load values from _ovly_table[$78].
 171  *      extern struct {
 172  *              u32 vma;
 173  *              u32 size;
 174  *              u32 file_offset;
 175  *              u32 buf;
 176  *      } _ovly_table[];
 177  */
 178         shli            off, $78, 4
 179         ila             tab, _ovly_table - 16
 180         lqx             vma, tab, off
 181         rotqbyi         buf, vma, 12
 182
 183 /* Load values from _ovly_buf_table[buf].
 184  *      extern struct {
 185  *              u32 mapped;
 186  *      } _ovly_buf_table[];
 187  */
 188         ila             tab, _ovly_buf_table
 189         ai              off, buf, -1
 190         shli            off, off, 2
 191         lqx             map, tab, off
 192         rotqby          cur, map, off
 193
 194 /* Branch to $79 now if overlay is already mapped.  */
 195         ceq             cmp, $78, cur
 196         brnz            cmp, __ovly_load_restore
 197
 198 /* Marker for profiling code.  If we get here, we are about to load
 199  * a new overlay.
 200  */
 201         .global         __ovly_load_event
 202         .type           __ovly_load_event, @function
 203 __ovly_load_event:
 204
 205 /* Set _ovly_buf_table[buf].mapped = $78. */
 206         cwx             genwi, tab, off
 207         shufb           map, $78, map, genwi
 208         stqx            map, tab, off
 209
 210 /* A new partition needs to be loaded. Prepare for DMA loop.
 211  * _EAR_ is the 64b base EA, filled in at run time by the
 212  * loader, and indicating the value for SPU executable image start.
 213  */
 214         lqd             cgshuf, (__cg_pattern-__ovly_return+4)(retval)
 215         rotqbyi         osize, vma, 4
 216         rotqbyi         sz, vma, 8
 217         lqa             ea64, _EAR_
 218
 219 __ovly_xfer_loop:
 220 /* 64b add to compute next ea64. */
 221         rotqmbyi        off64, sz, -4
 222         cg              cgbits, ea64, off64
 223         shufb           add64, cgbits, cgbits, cgshuf
 224         addx            add64, ea64, off64
 225         ori             ea64, add64, 0
 226
 227 /* Setup DMA parameters, then issue DMA request. */
 228         rotqbyi         ealo, add64, 4
 229         ila             maxsize, MFC_MAX_DMA_SIZE
 230         cgt             cmp, osize, maxsize
 231         selb            sz, osize, maxsize, cmp
 232         ila             tagid, MFC_TAG_ID
 233         wrch            $MFC_LSA, vma
 234         wrch            $MFC_EAH, ea64
 235         wrch            $MFC_EAL, ealo
 236         wrch            $MFC_Size, sz
 237         wrch            $MFC_TagId, tagid
 238         ila             cmd, MFC_GET_CMD
 239         wrch            $MFC_Cmd, cmd
 240
 241 /* Increment vma, decrement size, branch back as needed. */
 242         a               vma, vma, sz
 243         sf              osize, sz, osize
 244         brnz            osize, __ovly_xfer_loop
 245
 246 /* Save app's tagmask, wait for DMA complete, restore mask. */
 247         rdch            oldmask, $MFC_RdTagMask
 248 #if MFC_TAG_ID < 16
 249         ilh             newmask, 1 << MFC_TAG_ID
 250 #else
 251         ilhu            newmask, 1 << (MFC_TAG_ID - 16)
 252 #endif
 253         wrch            $MFC_WrTagMask, newmask
 254         ila             tagstat, MFC_TAG_UPDATE_ALL
 255         wrch            $MFC_WrTagUpdate, tagstat
 256         rdch            tagstat, $MFC_RdTagStat
 257         sync
 258         wrch            $MFC_WrTagMask, oldmask
 259
 260         .global         _ovly_debug_event
 261         .type           _ovly_debug_event, @function
 262 _ovly_debug_event:
 263 /* GDB inserts debugger trap here.  */
 264         nop
 265
 266 __ovly_load_restore:
 267 #ifdef OVLY_IRQ_SAVE
 268 /* Conditionally re-enable interrupts. */
 269         andi            irq_stat, irq_stat, 1
 270         ila             irqtmp, __ovly_irq_restore
 271         binze           irq_stat, irqtmp
 272 __ovly_irq_restore:
 273         lqd             $9, -64($sp)
 274 #endif
 275
 276 /* Restore saved registers. */
 277         lqd             $8, -48($sp)
 278         lqd             $7, -32($sp)
 279         lqd             $6, -16($sp)
 280
 281 __ovly_load_ret:
 282 /* Branch to target address. */
 283         bi              $79
 284
 285         .size           __ovly_load, . - __ovly_load