arch/sparc/kernel/rtrap.S

   1 /* $Id: rtrap.S,v 1.58 2002/01/31 03:30:05 davem Exp $
   2  * rtrap.S: Return from Sparc trap low-level code.
   3  *
   4  * Copyright (C) 1995 David S. Miller (davem@caip.rutgers.edu)
   5  */
   6
   7 #include <asm/page.h>
   8 #include <asm/ptrace.h>
   9 #include <asm/psr.h>
  10 #include <asm/asi.h>
  11 #include <asm/smp.h>
  12 #include <asm/contregs.h>
  13 #include <asm/winmacro.h>
  14 #include <asm/asmmacro.h>
  15 #include <asm/thread_info.h>
  16
  17 #define t_psr     l0
  18 #define t_pc      l1
  19 #define t_npc     l2
  20 #define t_wim     l3
  21 #define twin_tmp1 l4
  22 #define glob_tmp  g4
  23 #define curptr    g6
  24
  25         /* 7 WINDOW SPARC PATCH INSTRUCTIONS */
  26         .globl  rtrap_7win_patch1, rtrap_7win_patch2, rtrap_7win_patch3
  27         .globl  rtrap_7win_patch4, rtrap_7win_patch5
  28 rtrap_7win_patch1:      srl     %t_wim, 0x6, %glob_tmp
  29 rtrap_7win_patch2:      and     %glob_tmp, 0x7f, %glob_tmp
  30 rtrap_7win_patch3:      srl     %g1, 7, %g2
  31 rtrap_7win_patch4:      srl     %g2, 6, %g2
  32 rtrap_7win_patch5:      and     %g1, 0x7f, %g1
  33         /* END OF PATCH INSTRUCTIONS */
  34
  35         /* We need to check for a few things which are:
  36          * 1) The need to call schedule() because this
  37          *    processes quantum is up.
  38          * 2) Pending signals for this process, if any
  39          *    exist we need to call do_signal() to do
  40          *    the needy.
  41          *
  42          * Else we just check if the rett would land us
  43          * in an invalid window, if so we need to grab
  44          * it off the user/kernel stack first.
  45          */
  46
  47         .globl  ret_trap_entry, rtrap_patch1, rtrap_patch2
  48         .globl  rtrap_patch3, rtrap_patch4, rtrap_patch5
  49         .globl  ret_trap_lockless_ipi
  50 ret_trap_entry:
  51 ret_trap_lockless_ipi:
  52         andcc   %t_psr, PSR_PS, %g0
  53         be      1f
  54          nop
  55
  56         wr      %t_psr, 0x0, %psr
  57         b       ret_trap_kernel
  58          nop
  59
  60 1:
  61         ld      [%curptr + TI_FLAGS], %g2
  62         andcc   %g2, (_TIF_NEED_RESCHED), %g0
  63         be      signal_p
  64          nop
  65
  66         call    schedule
  67          nop
  68
  69         ld      [%curptr + TI_FLAGS], %g2
  70 signal_p:
  71         andcc   %g2, (_TIF_SIGPENDING|_TIF_RESTORE_SIGMASK), %g0
  72         bz,a    ret_trap_continue
  73          ld     [%sp + STACKFRAME_SZ + PT_PSR], %t_psr
  74
  75         mov     %l5, %o1
  76         mov     %l6, %o2
  77         call    do_signal
  78          add    %sp, STACKFRAME_SZ, %o0 ! pt_regs ptr
  79
  80         /* Fall through. */
  81         ld      [%sp + STACKFRAME_SZ + PT_PSR], %t_psr
  82         clr     %l6
  83 ret_trap_continue:
  84         wr      %t_psr, 0x0, %psr
  85         WRITE_PAUSE
  86
  87         ld      [%curptr + TI_W_SAVED], %twin_tmp1
  88         orcc    %g0, %twin_tmp1, %g0
  89         be      ret_trap_nobufwins
  90          nop
  91
  92         wr      %t_psr, PSR_ET, %psr
  93         WRITE_PAUSE
  94
  95         mov     1, %o1
  96         call    try_to_clear_window_buffer
  97          add    %sp, STACKFRAME_SZ, %o0
  98
  99         b       signal_p
 100          ld     [%curptr + TI_FLAGS], %g2
 101
 102 ret_trap_nobufwins:
 103         /* Load up the user's out registers so we can pull
 104          * a window from the stack, if necessary.
 105          */
 106         LOAD_PT_INS(sp)
 107
 108         /* If there are already live user windows in the
 109          * set we can return from trap safely.
 110          */
 111         ld      [%curptr + TI_UWINMASK], %twin_tmp1
 112         orcc    %g0, %twin_tmp1, %g0
 113         bne     ret_trap_userwins_ok
 114          nop
 115
 116                 /* Calculate new %wim, we have to pull a register
 117                  * window from the users stack.
 118                  */
 119 ret_trap_pull_one_window:
 120                 rd      %wim, %t_wim
 121                 sll     %t_wim, 0x1, %twin_tmp1
 122 rtrap_patch1:   srl     %t_wim, 0x7, %glob_tmp
 123                 or      %glob_tmp, %twin_tmp1, %glob_tmp
 124 rtrap_patch2:   and     %glob_tmp, 0xff, %glob_tmp
 125
 126                 wr      %glob_tmp, 0x0, %wim
 127
 128                                 /* Here comes the architecture specific
 129                                  * branch to the user stack checking routine
 130                                  * for return from traps.
 131                                  */
 132                                 .globl  rtrap_mmu_patchme
 133 rtrap_mmu_patchme:      b       sun4c_rett_stackchk
 134                                  andcc  %fp, 0x7, %g0
 135
 136 ret_trap_userwins_ok:
 137         LOAD_PT_PRIV(sp, t_psr, t_pc, t_npc)
 138         or      %t_pc, %t_npc, %g2
 139         andcc   %g2, 0x3, %g0
 140         be      1f
 141          nop
 142
 143         b       ret_trap_unaligned_pc
 144          add    %sp, STACKFRAME_SZ, %o0
 145
 146 1:
 147         LOAD_PT_YREG(sp, g1)
 148         LOAD_PT_GLOBALS(sp)
 149
 150         wr      %t_psr, 0x0, %psr
 151         WRITE_PAUSE
 152
 153         jmp     %t_pc
 154         rett    %t_npc
 155
 156 ret_trap_unaligned_pc:
 157         ld      [%sp + STACKFRAME_SZ + PT_PC], %o1
 158         ld      [%sp + STACKFRAME_SZ + PT_NPC], %o2
 159         ld      [%sp + STACKFRAME_SZ + PT_PSR], %o3
 160
 161         wr      %t_wim, 0x0, %wim               ! or else...
 162
 163         wr      %t_psr, PSR_ET, %psr
 164         WRITE_PAUSE
 165
 166         call    do_memaccess_unaligned
 167          nop
 168
 169         b       signal_p
 170          ld     [%curptr + TI_FLAGS], %g2
 171
 172 ret_trap_kernel:
 173                 /* Will the rett land us in the invalid window? */
 174                 mov     2, %g1
 175                 sll     %g1, %t_psr, %g1
 176 rtrap_patch3:   srl     %g1, 8, %g2
 177                 or      %g1, %g2, %g1
 178                 rd      %wim, %g2
 179                 andcc   %g2, %g1, %g0
 180                 be      1f              ! Nope, just return from the trap
 181                  sll    %g2, 0x1, %g1
 182
 183                 /* We have to grab a window before returning. */
 184 rtrap_patch4:   srl     %g2, 7,  %g2
 185                 or      %g1, %g2, %g1
 186 rtrap_patch5:   and     %g1, 0xff, %g1
 187
 188         wr      %g1, 0x0, %wim
 189
 190         /* Grrr, make sure we load from the right %sp... */
 191         LOAD_PT_ALL(sp, t_psr, t_pc, t_npc, g1)
 192
 193         restore %g0, %g0, %g0
 194         LOAD_WINDOW(sp)
 195         b       2f
 196          save   %g0, %g0, %g0
 197
 198         /* Reload the entire frame in case this is from a
 199          * kernel system call or whatever...
 200          */
 201 1:
 202         LOAD_PT_ALL(sp, t_psr, t_pc, t_npc, g1)
 203 2:
 204         wr      %t_psr, 0x0, %psr
 205         WRITE_PAUSE
 206
 207         jmp     %t_pc
 208         rett    %t_npc
 209
 210 ret_trap_user_stack_is_bolixed:
 211         wr      %t_wim, 0x0, %wim
 212
 213         wr      %t_psr, PSR_ET, %psr
 214         WRITE_PAUSE
 215
 216         call    window_ret_fault
 217          add    %sp, STACKFRAME_SZ, %o0
 218
 219         b       signal_p
 220          ld     [%curptr + TI_FLAGS], %g2
 221
 222
 223         .globl  sun4c_rett_stackchk
 224 sun4c_rett_stackchk:
 225         be      1f
 226          and    %fp, 0xfff, %g1         ! delay slot
 227
 228         b       ret_trap_user_stack_is_bolixed + 0x4
 229          wr     %t_wim, 0x0, %wim
 230
 231         /* See if we have to check the sanity of one page or two */
 232 1:
 233         add     %g1, 0x38, %g1
 234         sra     %fp, 29, %g2
 235         add     %g2, 0x1, %g2
 236         andncc  %g2, 0x1, %g0
 237         be      1f
 238          andncc %g1, 0xff8, %g0
 239
 240         /* %sp is in vma hole, yuck */
 241         b       ret_trap_user_stack_is_bolixed + 0x4
 242          wr     %t_wim, 0x0, %wim
 243
 244 1:
 245         be      sun4c_rett_onepage      /* Only one page to check */
 246          lda    [%fp] ASI_PTE, %g2
 247
 248 sun4c_rett_twopages:
 249         add     %fp, 0x38, %g1
 250         sra     %g1, 29, %g2
 251         add     %g2, 0x1, %g2
 252         andncc  %g2, 0x1, %g0
 253         be      1f
 254          lda    [%g1] ASI_PTE, %g2
 255
 256         /* Second page is in vma hole */
 257         b       ret_trap_user_stack_is_bolixed + 0x4
 258          wr     %t_wim, 0x0, %wim
 259
 260 1:
 261         srl     %g2, 29, %g2
 262         andcc   %g2, 0x4, %g0
 263         bne     sun4c_rett_onepage
 264          lda    [%fp] ASI_PTE, %g2
 265
 266         /* Second page has bad perms */
 267         b       ret_trap_user_stack_is_bolixed + 0x4
 268          wr     %t_wim, 0x0, %wim
 269
 270 sun4c_rett_onepage:
 271         srl     %g2, 29, %g2
 272         andcc   %g2, 0x4, %g0
 273         bne,a   1f
 274          restore %g0, %g0, %g0
 275
 276         /* A page had bad page permissions, losing... */
 277         b       ret_trap_user_stack_is_bolixed + 0x4
 278          wr     %t_wim, 0x0, %wim
 279
 280         /* Whee, things are ok, load the window and continue. */
 281 1:
 282         LOAD_WINDOW(sp)
 283
 284         b       ret_trap_userwins_ok
 285          save   %g0, %g0, %g0
 286
 287         .globl  srmmu_rett_stackchk
 288 srmmu_rett_stackchk:
 289         bne     ret_trap_user_stack_is_bolixed
 290          sethi   %hi(PAGE_OFFSET), %g1
 291         cmp     %g1, %fp
 292         bleu    ret_trap_user_stack_is_bolixed
 293          mov    AC_M_SFSR, %g1
 294         lda     [%g1] ASI_M_MMUREGS, %g0
 295
 296         lda     [%g0] ASI_M_MMUREGS, %g1
 297         or      %g1, 0x2, %g1
 298         sta     %g1, [%g0] ASI_M_MMUREGS
 299
 300         restore %g0, %g0, %g0
 301
 302         LOAD_WINDOW(sp)
 303
 304         save    %g0, %g0, %g0
 305
 306         andn    %g1, 0x2, %g1
 307         sta     %g1, [%g0] ASI_M_MMUREGS
 308
 309         mov     AC_M_SFAR, %g2
 310         lda     [%g2] ASI_M_MMUREGS, %g2
 311
 312         mov     AC_M_SFSR, %g1
 313         lda     [%g1] ASI_M_MMUREGS, %g1
 314         andcc   %g1, 0x2, %g0
 315         be      ret_trap_userwins_ok
 316          nop
 317
 318         b,a     ret_trap_user_stack_is_bolixed