arch/sparc/kernel/rtrap_32.S

   1 /*
   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         sethi   %hi(PSR_SYSCALL), %g1
  54         be      1f
  55          andn   %t_psr, %g1, %t_psr
  56
  57         wr      %t_psr, 0x0, %psr
  58         b       ret_trap_kernel
  59          nop
  60
  61 1:
  62         ld      [%curptr + TI_FLAGS], %g2
  63         andcc   %g2, (_TIF_NEED_RESCHED), %g0
  64         be      signal_p
  65          nop
  66
  67         call    schedule
  68          nop
  69
  70         ld      [%curptr + TI_FLAGS], %g2
  71 signal_p:
  72         andcc   %g2, _TIF_DO_NOTIFY_RESUME_MASK, %g0
  73         bz,a    ret_trap_continue
  74          ld     [%sp + STACKFRAME_SZ + PT_PSR], %t_psr
  75
  76         mov     %g2, %o2
  77         mov     %l5, %o1
  78         call    do_notify_resume
  79          add    %sp, STACKFRAME_SZ, %o0 ! pt_regs ptr
  80
  81         /* Fall through. */
  82         ld      [%sp + STACKFRAME_SZ + PT_PSR], %t_psr
  83         clr     %l6
  84 ret_trap_continue:
  85         sethi   %hi(PSR_SYSCALL), %g1
  86         andn    %t_psr, %g1, %t_psr
  87         wr      %t_psr, 0x0, %psr
  88         WRITE_PAUSE
  89
  90         ld      [%curptr + TI_W_SAVED], %twin_tmp1
  91         orcc    %g0, %twin_tmp1, %g0
  92         be      ret_trap_nobufwins
  93          nop
  94
  95         wr      %t_psr, PSR_ET, %psr
  96         WRITE_PAUSE
  97
  98         mov     1, %o1
  99         call    try_to_clear_window_buffer
 100          add    %sp, STACKFRAME_SZ, %o0
 101
 102         b       signal_p
 103          ld     [%curptr + TI_FLAGS], %g2
 104
 105 ret_trap_nobufwins:
 106         /* Load up the user's out registers so we can pull
 107          * a window from the stack, if necessary.
 108          */
 109         LOAD_PT_INS(sp)
 110
 111         /* If there are already live user windows in the
 112          * set we can return from trap safely.
 113          */
 114         ld      [%curptr + TI_UWINMASK], %twin_tmp1
 115         orcc    %g0, %twin_tmp1, %g0
 116         bne     ret_trap_userwins_ok
 117          nop
 118
 119                 /* Calculate new %wim, we have to pull a register
 120                  * window from the users stack.
 121                  */
 122 ret_trap_pull_one_window:
 123                 rd      %wim, %t_wim
 124                 sll     %t_wim, 0x1, %twin_tmp1
 125 rtrap_patch1:   srl     %t_wim, 0x7, %glob_tmp
 126                 or      %glob_tmp, %twin_tmp1, %glob_tmp
 127 rtrap_patch2:   and     %glob_tmp, 0xff, %glob_tmp
 128
 129                 wr      %glob_tmp, 0x0, %wim
 130
 131                                 /* Here comes the architecture specific
 132                                  * branch to the user stack checking routine
 133                                  * for return from traps.
 134                                  */
 135                                 .globl  rtrap_mmu_patchme
 136 rtrap_mmu_patchme:      b       sun4c_rett_stackchk
 137                                  andcc  %fp, 0x7, %g0
 138
 139 ret_trap_userwins_ok:
 140         LOAD_PT_PRIV(sp, t_psr, t_pc, t_npc)
 141         or      %t_pc, %t_npc, %g2
 142         andcc   %g2, 0x3, %g0
 143         sethi   %hi(PSR_SYSCALL), %g2
 144         be      1f
 145          andn   %t_psr, %g2, %t_psr
 146
 147         b       ret_trap_unaligned_pc
 148          add    %sp, STACKFRAME_SZ, %o0
 149
 150 1:
 151         LOAD_PT_YREG(sp, g1)
 152         LOAD_PT_GLOBALS(sp)
 153
 154         wr      %t_psr, 0x0, %psr
 155         WRITE_PAUSE
 156
 157         jmp     %t_pc
 158         rett    %t_npc
 159
 160 ret_trap_unaligned_pc:
 161         ld      [%sp + STACKFRAME_SZ + PT_PC], %o1
 162         ld      [%sp + STACKFRAME_SZ + PT_NPC], %o2
 163         ld      [%sp + STACKFRAME_SZ + PT_PSR], %o3
 164
 165         wr      %t_wim, 0x0, %wim               ! or else...
 166
 167         wr      %t_psr, PSR_ET, %psr
 168         WRITE_PAUSE
 169
 170         call    do_memaccess_unaligned
 171          nop
 172
 173         b       signal_p
 174          ld     [%curptr + TI_FLAGS], %g2
 175
 176 ret_trap_kernel:
 177                 /* Will the rett land us in the invalid window? */
 178                 mov     2, %g1
 179                 sll     %g1, %t_psr, %g1
 180 rtrap_patch3:   srl     %g1, 8, %g2
 181                 or      %g1, %g2, %g1
 182                 rd      %wim, %g2
 183                 andcc   %g2, %g1, %g0
 184                 be      1f              ! Nope, just return from the trap
 185                  sll    %g2, 0x1, %g1
 186
 187                 /* We have to grab a window before returning. */
 188 rtrap_patch4:   srl     %g2, 7,  %g2
 189                 or      %g1, %g2, %g1
 190 rtrap_patch5:   and     %g1, 0xff, %g1
 191
 192         wr      %g1, 0x0, %wim
 193
 194         /* Grrr, make sure we load from the right %sp... */
 195         LOAD_PT_ALL(sp, t_psr, t_pc, t_npc, g1)
 196
 197         restore %g0, %g0, %g0
 198         LOAD_WINDOW(sp)
 199         b       2f
 200          save   %g0, %g0, %g0
 201
 202         /* Reload the entire frame in case this is from a
 203          * kernel system call or whatever...
 204          */
 205 1:
 206         LOAD_PT_ALL(sp, t_psr, t_pc, t_npc, g1)
 207 2:
 208         sethi   %hi(PSR_SYSCALL), %twin_tmp1
 209         andn    %t_psr, %twin_tmp1, %t_psr
 210         wr      %t_psr, 0x0, %psr
 211         WRITE_PAUSE
 212
 213         jmp     %t_pc
 214         rett    %t_npc
 215
 216 ret_trap_user_stack_is_bolixed:
 217         wr      %t_wim, 0x0, %wim
 218
 219         wr      %t_psr, PSR_ET, %psr
 220         WRITE_PAUSE
 221
 222         call    window_ret_fault
 223          add    %sp, STACKFRAME_SZ, %o0
 224
 225         b       signal_p
 226          ld     [%curptr + TI_FLAGS], %g2
 227
 228 sun4c_rett_stackchk:
 229         be      1f
 230          and    %fp, 0xfff, %g1         ! delay slot
 231
 232         b       ret_trap_user_stack_is_bolixed + 0x4
 233          wr     %t_wim, 0x0, %wim
 234
 235         /* See if we have to check the sanity of one page or two */
 236 1:
 237         add     %g1, 0x38, %g1
 238         sra     %fp, 29, %g2
 239         add     %g2, 0x1, %g2
 240         andncc  %g2, 0x1, %g0
 241         be      1f
 242          andncc %g1, 0xff8, %g0
 243
 244         /* %sp is in vma hole, yuck */
 245         b       ret_trap_user_stack_is_bolixed + 0x4
 246          wr     %t_wim, 0x0, %wim
 247
 248 1:
 249         be      sun4c_rett_onepage      /* Only one page to check */
 250          lda    [%fp] ASI_PTE, %g2
 251
 252 sun4c_rett_twopages:
 253         add     %fp, 0x38, %g1
 254         sra     %g1, 29, %g2
 255         add     %g2, 0x1, %g2
 256         andncc  %g2, 0x1, %g0
 257         be      1f
 258          lda    [%g1] ASI_PTE, %g2
 259
 260         /* Second page is in vma hole */
 261         b       ret_trap_user_stack_is_bolixed + 0x4
 262          wr     %t_wim, 0x0, %wim
 263
 264 1:
 265         srl     %g2, 29, %g2
 266         andcc   %g2, 0x4, %g0
 267         bne     sun4c_rett_onepage
 268          lda    [%fp] ASI_PTE, %g2
 269
 270         /* Second page has bad perms */
 271         b       ret_trap_user_stack_is_bolixed + 0x4
 272          wr     %t_wim, 0x0, %wim
 273
 274 sun4c_rett_onepage:
 275         srl     %g2, 29, %g2
 276         andcc   %g2, 0x4, %g0
 277         bne,a   1f
 278          restore %g0, %g0, %g0
 279
 280         /* A page had bad page permissions, losing... */
 281         b       ret_trap_user_stack_is_bolixed + 0x4
 282          wr     %t_wim, 0x0, %wim
 283
 284         /* Whee, things are ok, load the window and continue. */
 285 1:
 286         LOAD_WINDOW(sp)
 287
 288         b       ret_trap_userwins_ok
 289          save   %g0, %g0, %g0
 290
 291         .globl  srmmu_rett_stackchk
 292 srmmu_rett_stackchk:
 293         bne     ret_trap_user_stack_is_bolixed
 294          sethi   %hi(PAGE_OFFSET), %g1
 295         cmp     %g1, %fp
 296         bleu    ret_trap_user_stack_is_bolixed
 297          mov    AC_M_SFSR, %g1
 298         lda     [%g1] ASI_M_MMUREGS, %g0
 299
 300         lda     [%g0] ASI_M_MMUREGS, %g1
 301         or      %g1, 0x2, %g1
 302         sta     %g1, [%g0] ASI_M_MMUREGS
 303
 304         restore %g0, %g0, %g0
 305
 306         LOAD_WINDOW(sp)
 307
 308         save    %g0, %g0, %g0
 309
 310         andn    %g1, 0x2, %g1
 311         sta     %g1, [%g0] ASI_M_MMUREGS
 312
 313         mov     AC_M_SFAR, %g2
 314         lda     [%g2] ASI_M_MMUREGS, %g2
 315
 316         mov     AC_M_SFSR, %g1
 317         lda     [%g1] ASI_M_MMUREGS, %g1
 318         andcc   %g1, 0x2, %g0
 319         be      ret_trap_userwins_ok
 320          nop
 321
 322         b,a     ret_trap_user_stack_is_bolixed