arch/m68k/include/asm/entry.h

   1 #ifndef __M68K_ENTRY_H
   2 #define __M68K_ENTRY_H
   3
   4 #include <asm/setup.h>
   5 #include <asm/page.h>
   6 #ifdef __ASSEMBLY__
   7 #include <asm/thread_info.h>
   8 #endif
   9
  10 /*
  11  * Stack layout in 'ret_from_exception':
  12  *
  13  *      This allows access to the syscall arguments in registers d1-d5
  14  *
  15  *       0(sp) - d1
  16  *       4(sp) - d2
  17  *       8(sp) - d3
  18  *       C(sp) - d4
  19  *      10(sp) - d5
  20  *      14(sp) - a0
  21  *      18(sp) - a1
  22  *      1C(sp) - a2
  23  *      20(sp) - d0
  24  *      24(sp) - orig_d0
  25  *      28(sp) - stack adjustment
  26  *      2C(sp) - [ sr              ] [ format & vector ]
  27  *      2E(sp) - [ pc-hiword       ] [ sr              ]
  28  *      30(sp) - [ pc-loword       ] [ pc-hiword       ]
  29  *      32(sp) - [ format & vector ] [ pc-loword       ]
  30  *                ^^^^^^^^^^^^^^^^^   ^^^^^^^^^^^^^^^^^
  31  *                      M68K              COLDFIRE
  32  */
  33
  34 /* the following macro is used when enabling interrupts */
  35 #if defined(MACH_ATARI_ONLY)
  36         /* block out HSYNC on the atari */
  37 #define ALLOWINT        (~0x400)
  38 #define MAX_NOINT_IPL   3
  39 #else
  40         /* portable version */
  41 #define ALLOWINT        (~0x700)
  42 #define MAX_NOINT_IPL   0
  43 #endif /* machine compilation types */
  44
  45 #ifdef __ASSEMBLY__
  46 /*
  47  * This defines the normal kernel pt-regs layout.
  48  *
  49  * regs a3-a6 and d6-d7 are preserved by C code
  50  * the kernel doesn't mess with usp unless it needs to
  51  */
  52 #define SWITCH_STACK_SIZE       (6*4+4) /* includes return address */
  53
  54 #ifdef CONFIG_COLDFIRE
  55 #ifdef CONFIG_COLDFIRE_SW_A7
  56 /*
  57  * This is made a little more tricky on older ColdFires. There is no
  58  * separate supervisor and user stack pointers. Need to artificially
  59  * construct a usp in software... When doing this we need to disable
  60  * interrupts, otherwise bad things will happen.
  61  */
  62 .globl sw_usp
  63 .globl sw_ksp
  64
  65 .macro SAVE_ALL_SYS
  66         move    #0x2700,%sr             /* disable intrs */
  67         btst    #5,%sp@(2)              /* from user? */
  68         bnes    6f                      /* no, skip */
  69         movel   %sp,sw_usp              /* save user sp */
  70         addql   #8,sw_usp               /* remove exception */
  71         movel   sw_ksp,%sp              /* kernel sp */
  72         subql   #8,%sp                  /* room for exception */
  73         clrl    %sp@-                   /* stkadj */
  74         movel   %d0,%sp@-               /* orig d0 */
  75         movel   %d0,%sp@-               /* d0 */
  76         lea     %sp@(-32),%sp           /* space for 8 regs */
  77         moveml  %d1-%d5/%a0-%a2,%sp@
  78         movel   sw_usp,%a0              /* get usp */
  79         movel   %a0@-,%sp@(PT_OFF_PC)   /* copy exception program counter */
  80         movel   %a0@-,%sp@(PT_OFF_FORMATVEC)/*copy exception format/vector/sr */
  81         bra     7f
  82         6:
  83         clrl    %sp@-                   /* stkadj */
  84         movel   %d0,%sp@-               /* orig d0 */
  85         movel   %d0,%sp@-               /* d0 */
  86         lea     %sp@(-32),%sp           /* space for 8 regs */
  87         moveml  %d1-%d5/%a0-%a2,%sp@
  88         7:
  89 .endm
  90
  91 .macro SAVE_ALL_INT
  92         SAVE_ALL_SYS
  93         moveq   #-1,%d0                 /* not system call entry */
  94         movel   %d0,%sp@(PT_OFF_ORIG_D0)
  95 .endm
  96
  97 .macro RESTORE_USER
  98         move    #0x2700,%sr             /* disable intrs */
  99         movel   sw_usp,%a0              /* get usp */
 100         movel   %sp@(PT_OFF_PC),%a0@-   /* copy exception program counter */
 101         movel   %sp@(PT_OFF_FORMATVEC),%a0@-/*copy exception format/vector/sr */
 102         moveml  %sp@,%d1-%d5/%a0-%a2
 103         lea     %sp@(32),%sp            /* space for 8 regs */
 104         movel   %sp@+,%d0
 105         addql   #4,%sp                  /* orig d0 */
 106         addl    %sp@+,%sp               /* stkadj */
 107         addql   #8,%sp                  /* remove exception */
 108         movel   %sp,sw_ksp              /* save ksp */
 109         subql   #8,sw_usp               /* set exception */
 110         movel   sw_usp,%sp              /* restore usp */
 111         rte
 112 .endm
 113
 114 .macro RDUSP
 115         movel   sw_usp,%a3
 116 .endm
 117
 118 .macro WRUSP
 119         movel   %a3,sw_usp
 120 .endm
 121
 122 #else /* !CONFIG_COLDFIRE_SW_A7 */
 123 /*
 124  * Modern ColdFire parts have separate supervisor and user stack
 125  * pointers. Simple load and restore macros for this case.
 126  */
 127 .macro SAVE_ALL_SYS
 128         move    #0x2700,%sr             /* disable intrs */
 129         clrl    %sp@-                   /* stkadj */
 130         movel   %d0,%sp@-               /* orig d0 */
 131         movel   %d0,%sp@-               /* d0 */
 132         lea     %sp@(-32),%sp           /* space for 8 regs */
 133         moveml  %d1-%d5/%a0-%a2,%sp@
 134 .endm
 135
 136 .macro SAVE_ALL_INT
 137         move    #0x2700,%sr             /* disable intrs */
 138         clrl    %sp@-                   /* stkadj */
 139         pea     -1:w                    /* orig d0 */
 140         movel   %d0,%sp@-               /* d0 */
 141         lea     %sp@(-32),%sp           /* space for 8 regs */
 142         moveml  %d1-%d5/%a0-%a2,%sp@
 143 .endm
 144
 145 .macro RESTORE_USER
 146         moveml  %sp@,%d1-%d5/%a0-%a2
 147         lea     %sp@(32),%sp            /* space for 8 regs */
 148         movel   %sp@+,%d0
 149         addql   #4,%sp                  /* orig d0 */
 150         addl    %sp@+,%sp               /* stkadj */
 151         rte
 152 .endm
 153
 154 .macro RDUSP
 155         /*move  %usp,%a3*/
 156         .word   0x4e6b
 157 .endm
 158
 159 .macro WRUSP
 160         /*move  %a3,%usp*/
 161         .word   0x4e63
 162 .endm
 163
 164 #endif /* !CONFIG_COLDFIRE_SW_A7 */
 165
 166 .macro SAVE_SWITCH_STACK
 167         lea     %sp@(-24),%sp           /* 6 regs */
 168         moveml  %a3-%a6/%d6-%d7,%sp@
 169 .endm
 170
 171 .macro RESTORE_SWITCH_STACK
 172         moveml  %sp@,%a3-%a6/%d6-%d7
 173         lea     %sp@(24),%sp            /* 6 regs */
 174 .endm
 175
 176 #else /* !CONFIG_COLDFIRE */
 177
 178 /*
 179  * All other types of m68k parts (68000, 680x0, CPU32) have the same
 180  * entry and exit code.
 181  */
 182
 183 /*
 184  * a -1 in the orig_d0 field signifies
 185  * that the stack frame is NOT for syscall
 186  */
 187 .macro SAVE_ALL_INT
 188         clrl    %sp@-                   /* stk_adj */
 189         pea     -1:w                    /* orig d0 */
 190         movel   %d0,%sp@-               /* d0 */
 191         moveml  %d1-%d5/%a0-%a2,%sp@-
 192 .endm
 193
 194 .macro SAVE_ALL_SYS
 195         clrl    %sp@-                   /* stk_adj */
 196         movel   %d0,%sp@-               /* orig d0 */
 197         movel   %d0,%sp@-               /* d0 */
 198         moveml  %d1-%d5/%a0-%a2,%sp@-
 199 .endm
 200
 201 .macro RESTORE_ALL
 202         moveml  %sp@+,%a0-%a2/%d1-%d5
 203         movel   %sp@+,%d0
 204         addql   #4,%sp                  /* orig d0 */
 205         addl    %sp@+,%sp               /* stk adj */
 206         rte
 207 .endm
 208
 209
 210 .macro SAVE_SWITCH_STACK
 211         moveml  %a3-%a6/%d6-%d7,%sp@-
 212 .endm
 213
 214 .macro RESTORE_SWITCH_STACK
 215         moveml  %sp@+,%a3-%a6/%d6-%d7
 216 .endm
 217
 218 #endif /* !CONFIG_COLDFIRE */
 219
 220 /*
 221  * Register %a2 is reserved and set to current task on MMU enabled systems.
 222  * Non-MMU systems do not reserve %a2 in this way, and this definition is
 223  * not used for them.
 224  */
 225 #ifdef CONFIG_MMU
 226
 227 #define curptr a2
 228
 229 #define GET_CURRENT(tmp) get_current tmp
 230 .macro get_current reg=%d0
 231         movel   %sp,\reg
 232         andl    #-THREAD_SIZE,\reg
 233         movel   \reg,%curptr
 234         movel   %curptr@,%curptr
 235 .endm
 236
 237 #else
 238
 239 #define GET_CURRENT(tmp)
 240
 241 #endif /* CONFIG_MMU */
 242
 243 #else /* C source */
 244
 245 #define STR(X) STR1(X)
 246 #define STR1(X) #X
 247
 248 #define SAVE_ALL_INT                            \
 249         "clrl   %%sp@-;"    /* stk_adj */       \
 250         "pea    -1:w;"      /* orig d0 = -1 */  \
 251         "movel  %%d0,%%sp@-;" /* d0 */          \
 252         "moveml %%d1-%%d5/%%a0-%%a2,%%sp@-"
 253
 254 #define GET_CURRENT(tmp) \
 255         "movel  %%sp,"#tmp"\n\t" \
 256         "andw   #-"STR(THREAD_SIZE)","#tmp"\n\t" \
 257         "movel  "#tmp",%%a2\n\t" \
 258         "movel  %%a2@,%%a2"
 259
 260 #endif
 261
 262 #endif /* __M68K_ENTRY_H */