arch/m68k/include/asm/entry.h

   1 /* SPDX-License-Identifier: GPL-2.0 */
   2 #ifndef __M68K_ENTRY_H
   3 #define __M68K_ENTRY_H
   4
   5 #include <asm/setup.h>
   6 #include <asm/page.h>
   7 #ifdef __ASSEMBLY__
   8 #include <asm/thread_info.h>
   9 #endif
  10
  11 /*
  12  * Stack layout in 'ret_from_exception':
  13  *
  14  *      This allows access to the syscall arguments in registers d1-d5
  15  *
  16  *       0(sp) - d1
  17  *       4(sp) - d2
  18  *       8(sp) - d3
  19  *       C(sp) - d4
  20  *      10(sp) - d5
  21  *      14(sp) - a0
  22  *      18(sp) - a1
  23  *      1C(sp) - a2
  24  *      20(sp) - d0
  25  *      24(sp) - orig_d0
  26  *      28(sp) - stack adjustment
  27  *      2C(sp) - [ sr              ] [ format & vector ]
  28  *      2E(sp) - [ pc-hiword       ] [ sr              ]
  29  *      30(sp) - [ pc-loword       ] [ pc-hiword       ]
  30  *      32(sp) - [ format & vector ] [ pc-loword       ]
  31  *                ^^^^^^^^^^^^^^^^^   ^^^^^^^^^^^^^^^^^
  32  *                      M68K              COLDFIRE
  33  */
  34
  35 /* the following macro is used when enabling interrupts */
  36 #if defined(MACH_ATARI_ONLY)
  37         /* block out HSYNC = ipl 2 on the atari */
  38 #define ALLOWINT        (~0x500)
  39 #else
  40         /* portable version */
  41 #define ALLOWINT        (~0x700)
  42 #endif /* machine compilation types */
  43
  44 #ifdef __ASSEMBLY__
  45 /*
  46  * This defines the normal kernel pt-regs layout.
  47  *
  48  * regs a3-a6 and d6-d7 are preserved by C code
  49  * the kernel doesn't mess with usp unless it needs to
  50  */
  51 #define SWITCH_STACK_SIZE       (6*4+4) /* includes return address */
  52
  53 #ifdef CONFIG_COLDFIRE
  54 #ifdef CONFIG_COLDFIRE_SW_A7
  55 /*
  56  * This is made a little more tricky on older ColdFires. There is no
  57  * separate supervisor and user stack pointers. Need to artificially
  58  * construct a usp in software... When doing this we need to disable
  59  * interrupts, otherwise bad things will happen.
  60  */
  61 .globl sw_usp
  62 .globl sw_ksp
  63
  64 .macro SAVE_ALL_SYS
  65         move    #0x2700,%sr             /* disable intrs */
  66         btst    #5,%sp@(2)              /* from user? */
  67         bnes    6f                      /* no, skip */
  68         movel   %sp,sw_usp              /* save user sp */
  69         addql   #8,sw_usp               /* remove exception */
  70         movel   sw_ksp,%sp              /* kernel sp */
  71         subql   #8,%sp                  /* room for exception */
  72         clrl    %sp@-                   /* stkadj */
  73         movel   %d0,%sp@-               /* orig d0 */
  74         movel   %d0,%sp@-               /* d0 */
  75         lea     %sp@(-32),%sp           /* space for 8 regs */
  76         moveml  %d1-%d5/%a0-%a2,%sp@
  77         movel   sw_usp,%a0              /* get usp */
  78         movel   %a0@-,%sp@(PT_OFF_PC)   /* copy exception program counter */
  79         movel   %a0@-,%sp@(PT_OFF_FORMATVEC)/*copy exception format/vector/sr */
  80         bra     7f
  81         6:
  82         clrl    %sp@-                   /* stkadj */
  83         movel   %d0,%sp@-               /* orig d0 */
  84         movel   %d0,%sp@-               /* d0 */
  85         lea     %sp@(-32),%sp           /* space for 8 regs */
  86         moveml  %d1-%d5/%a0-%a2,%sp@
  87         7:
  88 .endm
  89
  90 .macro SAVE_ALL_INT
  91         SAVE_ALL_SYS
  92         moveq   #-1,%d0                 /* not system call entry */
  93         movel   %d0,%sp@(PT_OFF_ORIG_D0)
  94 .endm
  95
  96 .macro RESTORE_USER
  97         move    #0x2700,%sr             /* disable intrs */
  98         movel   sw_usp,%a0              /* get usp */
  99         movel   %sp@(PT_OFF_PC),%a0@-   /* copy exception program counter */
 100         movel   %sp@(PT_OFF_FORMATVEC),%a0@-/*copy exception format/vector/sr */
 101         moveml  %sp@,%d1-%d5/%a0-%a2
 102         lea     %sp@(32),%sp            /* space for 8 regs */
 103         movel   %sp@+,%d0
 104         addql   #4,%sp                  /* orig d0 */
 105         addl    %sp@+,%sp               /* stkadj */
 106         addql   #8,%sp                  /* remove exception */
 107         movel   %sp,sw_ksp              /* save ksp */
 108         subql   #8,sw_usp               /* set exception */
 109         movel   sw_usp,%sp              /* restore usp */
 110         rte
 111 .endm
 112
 113 .macro RDUSP
 114         movel   sw_usp,%a3
 115 .endm
 116
 117 .macro WRUSP
 118         movel   %a3,sw_usp
 119 .endm
 120
 121 #else /* !CONFIG_COLDFIRE_SW_A7 */
 122 /*
 123  * Modern ColdFire parts have separate supervisor and user stack
 124  * pointers. Simple load and restore macros for this case.
 125  */
 126 .macro SAVE_ALL_SYS
 127         move    #0x2700,%sr             /* disable intrs */
 128         clrl    %sp@-                   /* stkadj */
 129         movel   %d0,%sp@-               /* orig d0 */
 130         movel   %d0,%sp@-               /* d0 */
 131         lea     %sp@(-32),%sp           /* space for 8 regs */
 132         moveml  %d1-%d5/%a0-%a2,%sp@
 133 .endm
 134
 135 .macro SAVE_ALL_INT
 136         move    #0x2700,%sr             /* disable intrs */
 137         clrl    %sp@-                   /* stkadj */
 138         pea     -1:w                    /* orig d0 */
 139         movel   %d0,%sp@-               /* d0 */
 140         lea     %sp@(-32),%sp           /* space for 8 regs */
 141         moveml  %d1-%d5/%a0-%a2,%sp@
 142 .endm
 143
 144 .macro RESTORE_USER
 145         moveml  %sp@,%d1-%d5/%a0-%a2
 146         lea     %sp@(32),%sp            /* space for 8 regs */
 147         movel   %sp@+,%d0
 148         addql   #4,%sp                  /* orig d0 */
 149         addl    %sp@+,%sp               /* stkadj */
 150         rte
 151 .endm
 152
 153 .macro RDUSP
 154         /*move  %usp,%a3*/
 155         .word   0x4e6b
 156 .endm
 157
 158 .macro WRUSP
 159         /*move  %a3,%usp*/
 160         .word   0x4e63
 161 .endm
 162
 163 #endif /* !CONFIG_COLDFIRE_SW_A7 */
 164
 165 .macro SAVE_SWITCH_STACK
 166         lea     %sp@(-24),%sp           /* 6 regs */
 167         moveml  %a3-%a6/%d6-%d7,%sp@
 168 .endm
 169
 170 .macro RESTORE_SWITCH_STACK
 171         moveml  %sp@,%a3-%a6/%d6-%d7
 172         lea     %sp@(24),%sp            /* 6 regs */
 173 .endm
 174
 175 #else /* !CONFIG_COLDFIRE */
 176
 177 /*
 178  * All other types of m68k parts (68000, 680x0, CPU32) have the same
 179  * entry and exit code.
 180  */
 181
 182 /*
 183  * a -1 in the orig_d0 field signifies
 184  * that the stack frame is NOT for syscall
 185  */
 186 .macro SAVE_ALL_INT
 187         clrl    %sp@-                   /* stk_adj */
 188         pea     -1:w                    /* orig d0 */
 189         movel   %d0,%sp@-               /* d0 */
 190         moveml  %d1-%d5/%a0-%a2,%sp@-
 191 .endm
 192
 193 .macro SAVE_ALL_SYS
 194         clrl    %sp@-                   /* stk_adj */
 195         movel   %d0,%sp@-               /* orig d0 */
 196         movel   %d0,%sp@-               /* d0 */
 197         moveml  %d1-%d5/%a0-%a2,%sp@-
 198 .endm
 199
 200 .macro RESTORE_ALL
 201         moveml  %sp@+,%a0-%a2/%d1-%d5
 202         movel   %sp@+,%d0
 203         addql   #4,%sp                  /* orig d0 */
 204         addl    %sp@+,%sp               /* stk adj */
 205         rte
 206 .endm
 207
 208
 209 .macro SAVE_SWITCH_STACK
 210         moveml  %a3-%a6/%d6-%d7,%sp@-
 211 .endm
 212
 213 .macro RESTORE_SWITCH_STACK
 214         moveml  %sp@+,%a3-%a6/%d6-%d7
 215 .endm
 216
 217 #endif /* !CONFIG_COLDFIRE */
 218
 219 /*
 220  * Register %a2 is reserved and set to current task on MMU enabled systems.
 221  * Non-MMU systems do not reserve %a2 in this way, and this definition is
 222  * not used for them.
 223  */
 224 #ifdef CONFIG_MMU
 225
 226 #define curptr a2
 227
 228 #define GET_CURRENT(tmp) get_current tmp
 229 .macro get_current reg=%d0
 230         movel   %sp,\reg
 231         andl    #-THREAD_SIZE,\reg
 232         movel   \reg,%curptr
 233         movel   %curptr@,%curptr
 234 .endm
 235
 236 #else
 237
 238 #define GET_CURRENT(tmp)
 239
 240 #endif /* CONFIG_MMU */
 241
 242 #else /* C source */
 243
 244 #define STR(X) STR1(X)
 245 #define STR1(X) #X
 246
 247 #define SAVE_ALL_INT                            \
 248         "clrl   %%sp@-;"    /* stk_adj */       \
 249         "pea    -1:w;"      /* orig d0 = -1 */  \
 250         "movel  %%d0,%%sp@-;" /* d0 */          \
 251         "moveml %%d1-%%d5/%%a0-%%a2,%%sp@-"
 252
 253 #define GET_CURRENT(tmp) \
 254         "movel  %%sp,"#tmp"\n\t" \
 255         "andw   #-"STR(THREAD_SIZE)","#tmp"\n\t" \
 256         "movel  "#tmp",%%a2\n\t" \
 257         "movel  %%a2@,%%a2"
 258
 259 #endif
 260
 261 #endif /* __M68K_ENTRY_H */