arch/sparc/kernel/rtrap_64.S

   1 /*
   2  * rtrap.S: Preparing for return from trap on Sparc V9.
   3  *
   4  * Copyright (C) 1997,1998 Jakub Jelinek (jj@sunsite.mff.cuni.cz)
   5  * Copyright (C) 1997 David S. Miller (davem@caip.rutgers.edu)
   6  */
   7
   8
   9 #include <asm/asi.h>
  10 #include <asm/pstate.h>
  11 #include <asm/ptrace.h>
  12 #include <asm/spitfire.h>
  13 #include <asm/head.h>
  14 #include <asm/visasm.h>
  15 #include <asm/processor.h>
  16
  17 #define         RTRAP_PSTATE            (PSTATE_TSO|PSTATE_PEF|PSTATE_PRIV|PSTATE_IE)
  18 #define         RTRAP_PSTATE_IRQOFF     (PSTATE_TSO|PSTATE_PEF|PSTATE_PRIV)
  19 #define         RTRAP_PSTATE_AG_IRQOFF  (PSTATE_TSO|PSTATE_PEF|PSTATE_PRIV|PSTATE_AG)
  20
  21 #ifdef CONFIG_CONTEXT_TRACKING
  22 # define SCHEDULE_USER schedule_user
  23 #else
  24 # define SCHEDULE_USER schedule
  25 #endif
  26
  27                 .text
  28                 .align                  32
  29 __handle_preemption:
  30                 call                    SCHEDULE_USER
  31                  wrpr                   %g0, RTRAP_PSTATE, %pstate
  32                 ba,pt                   %xcc, __handle_preemption_continue
  33                  wrpr                   %g0, RTRAP_PSTATE_IRQOFF, %pstate
  34
  35 __handle_user_windows:
  36                 call                    fault_in_user_windows
  37                  wrpr                   %g0, RTRAP_PSTATE, %pstate
  38                 ba,pt                   %xcc, __handle_preemption_continue
  39                  wrpr                   %g0, RTRAP_PSTATE_IRQOFF, %pstate
  40
  41 __handle_userfpu:
  42                 rd                      %fprs, %l5
  43                 andcc                   %l5, FPRS_FEF, %g0
  44                 sethi                   %hi(TSTATE_PEF), %o0
  45                 be,a,pn                 %icc, __handle_userfpu_continue
  46                  andn                   %l1, %o0, %l1
  47                 ba,a,pt                 %xcc, __handle_userfpu_continue
  48
  49 __handle_signal:
  50                 mov                     %l5, %o1
  51                 add                     %sp, PTREGS_OFF, %o0
  52                 mov                     %l0, %o2
  53                 call                    do_notify_resume
  54                  wrpr                   %g0, RTRAP_PSTATE, %pstate
  55                 wrpr                    %g0, RTRAP_PSTATE_IRQOFF, %pstate
  56
  57                 /* Signal delivery can modify pt_regs tstate, so we must
  58                  * reload it.
  59                  */
  60                 ldx                     [%sp + PTREGS_OFF + PT_V9_TSTATE], %l1
  61                 sethi                   %hi(0xf << 20), %l4
  62                 and                     %l1, %l4, %l4
  63                 ba,pt                   %xcc, __handle_preemption_continue
  64                  andn                   %l1, %l4, %l1
  65
  66                 /* When returning from a NMI (%pil==15) interrupt we want to
  67                  * avoid running softirqs, doing IRQ tracing, preempting, etc.
  68                  */
  69                 .globl                  rtrap_nmi
  70 rtrap_nmi:      ldx                     [%sp + PTREGS_OFF + PT_V9_TSTATE], %l1
  71                 sethi                   %hi(0xf << 20), %l4
  72                 and                     %l1, %l4, %l4
  73                 andn                    %l1, %l4, %l1
  74                 srl                     %l4, 20, %l4
  75                 ba,pt                   %xcc, rtrap_no_irq_enable
  76                  wrpr                   %l4, %pil
  77
  78                 .align                  64
  79                 .globl                  rtrap_irq, rtrap, irqsz_patchme, rtrap_xcall
  80 rtrap_irq:
  81 rtrap:
  82                 /* mm/ultra.S:xcall_report_regs KNOWS about this load. */
  83                 ldx                     [%sp + PTREGS_OFF + PT_V9_TSTATE], %l1
  84 rtrap_xcall:
  85                 sethi                   %hi(0xf << 20), %l4
  86                 and                     %l1, %l4, %l4
  87                 andn                    %l1, %l4, %l1
  88                 srl                     %l4, 20, %l4
  89 #ifdef CONFIG_TRACE_IRQFLAGS
  90                 brnz,pn                 %l4, rtrap_no_irq_enable
  91                  nop
  92                 call                    trace_hardirqs_on
  93                  nop
  94                 /* Do not actually set the %pil here.  We will do that
  95                  * below after we clear PSTATE_IE in the %pstate register.
  96                  * If we re-enable interrupts here, we can recurse down
  97                  * the hardirq stack potentially endlessly, causing a
  98                  * stack overflow.
  99                  *
 100                  * It is tempting to put this test and trace_hardirqs_on
 101                  * call at the 'rt_continue' label, but that will not work
 102                  * as that path hits unconditionally and we do not want to
 103                  * execute this in NMI return paths, for example.
 104                  */
 105 #endif
 106 rtrap_no_irq_enable:
 107                 andcc                   %l1, TSTATE_PRIV, %l3
 108                 bne,pn                  %icc, to_kernel
 109                  nop
 110
 111                 /* We must hold IRQs off and atomically test schedule+signal
 112                  * state, then hold them off all the way back to userspace.
 113                  * If we are returning to kernel, none of this matters.  Note
 114                  * that we are disabling interrupts via PSTATE_IE, not using
 115                  * %pil.
 116                  *
 117                  * If we do not do this, there is a window where we would do
 118                  * the tests, later the signal/resched event arrives but we do
 119                  * not process it since we are still in kernel mode.  It would
 120                  * take until the next local IRQ before the signal/resched
 121                  * event would be handled.
 122                  *
 123                  * This also means that if we have to deal with user
 124                  * windows, we have to redo all of these sched+signal checks
 125                  * with IRQs disabled.
 126                  */
 127 to_user:        wrpr                    %g0, RTRAP_PSTATE_IRQOFF, %pstate
 128                 wrpr                    0, %pil
 129 __handle_preemption_continue:
 130                 ldx                     [%g6 + TI_FLAGS], %l0
 131                 sethi                   %hi(_TIF_USER_WORK_MASK), %o0
 132                 or                      %o0, %lo(_TIF_USER_WORK_MASK), %o0
 133                 andcc                   %l0, %o0, %g0
 134                 sethi                   %hi(TSTATE_PEF), %o0
 135                 be,pt                   %xcc, user_nowork
 136                  andcc                  %l1, %o0, %g0
 137                 andcc                   %l0, _TIF_NEED_RESCHED, %g0
 138                 bne,pn                  %xcc, __handle_preemption
 139                  andcc                  %l0, _TIF_DO_NOTIFY_RESUME_MASK, %g0
 140                 bne,pn                  %xcc, __handle_signal
 141                  ldub                   [%g6 + TI_WSAVED], %o2
 142                 brnz,pn                 %o2, __handle_user_windows
 143                  nop
 144                 sethi                   %hi(TSTATE_PEF), %o0
 145                 andcc                   %l1, %o0, %g0
 146
 147                 /* This fpdepth clear is necessary for non-syscall rtraps only */
 148 user_nowork:
 149                 bne,pn                  %xcc, __handle_userfpu
 150                  stb                    %g0, [%g6 + TI_FPDEPTH]
 151 __handle_userfpu_continue:
 152
 153 rt_continue:    ldx                     [%sp + PTREGS_OFF + PT_V9_G1], %g1
 154                 ldx                     [%sp + PTREGS_OFF + PT_V9_G2], %g2
 155
 156                 ldx                     [%sp + PTREGS_OFF + PT_V9_G3], %g3
 157                 ldx                     [%sp + PTREGS_OFF + PT_V9_G4], %g4
 158                 ldx                     [%sp + PTREGS_OFF + PT_V9_G5], %g5
 159                 brz,pt                  %l3, 1f
 160                 mov                     %g6, %l2
 161
 162                 /* Must do this before thread reg is clobbered below.  */
 163                 LOAD_PER_CPU_BASE(%g5, %g6, %i0, %i1, %i2)
 164 1:
 165                 ldx                     [%sp + PTREGS_OFF + PT_V9_G6], %g6
 166                 ldx                     [%sp + PTREGS_OFF + PT_V9_G7], %g7
 167
 168                 /* Normal globals are restored, go to trap globals.  */
 169 661:            wrpr                    %g0, RTRAP_PSTATE_AG_IRQOFF, %pstate
 170                 nop
 171                 .section                .sun4v_2insn_patch, "ax"
 172                 .word                   661b
 173                 wrpr                    %g0, RTRAP_PSTATE_IRQOFF, %pstate
 174                 SET_GL(1)
 175                 .previous
 176
 177                 mov                     %l2, %g6
 178
 179                 ldx                     [%sp + PTREGS_OFF + PT_V9_I0], %i0
 180                 ldx                     [%sp + PTREGS_OFF + PT_V9_I1], %i1
 181
 182                 ldx                     [%sp + PTREGS_OFF + PT_V9_I2], %i2
 183                 ldx                     [%sp + PTREGS_OFF + PT_V9_I3], %i3
 184                 ldx                     [%sp + PTREGS_OFF + PT_V9_I4], %i4
 185                 ldx                     [%sp + PTREGS_OFF + PT_V9_I5], %i5
 186                 ldx                     [%sp + PTREGS_OFF + PT_V9_I6], %i6
 187                 ldx                     [%sp + PTREGS_OFF + PT_V9_I7], %i7
 188                 ldx                     [%sp + PTREGS_OFF + PT_V9_TPC], %l2
 189                 ldx                     [%sp + PTREGS_OFF + PT_V9_TNPC], %o2
 190
 191                 ld                      [%sp + PTREGS_OFF + PT_V9_Y], %o3
 192                 wr                      %o3, %g0, %y
 193                 wrpr                    %l4, 0x0, %pil
 194                 wrpr                    %g0, 0x1, %tl
 195                 andn                    %l1, TSTATE_SYSCALL, %l1
 196                 wrpr                    %l1, %g0, %tstate
 197                 wrpr                    %l2, %g0, %tpc
 198                 wrpr                    %o2, %g0, %tnpc
 199
 200                 brnz,pn                 %l3, kern_rtt
 201                  mov                    PRIMARY_CONTEXT, %l7
 202
 203 661:            ldxa                    [%l7 + %l7] ASI_DMMU, %l0
 204                 .section                .sun4v_1insn_patch, "ax"
 205                 .word                   661b
 206                 ldxa                    [%l7 + %l7] ASI_MMU, %l0
 207                 .previous
 208
 209                 sethi                   %hi(sparc64_kern_pri_nuc_bits), %l1
 210                 ldx                     [%l1 + %lo(sparc64_kern_pri_nuc_bits)], %l1
 211                 or                      %l0, %l1, %l0
 212
 213 661:            stxa                    %l0, [%l7] ASI_DMMU
 214                 .section                .sun4v_1insn_patch, "ax"
 215                 .word                   661b
 216                 stxa                    %l0, [%l7] ASI_MMU
 217                 .previous
 218
 219                 sethi                   %hi(KERNBASE), %l7
 220                 flush                   %l7
 221                 rdpr                    %wstate, %l1
 222                 rdpr                    %otherwin, %l2
 223                 srl                     %l1, 3, %l1
 224
 225                 wrpr                    %l2, %g0, %canrestore
 226                 wrpr                    %l1, %g0, %wstate
 227                 brnz,pt                 %l2, user_rtt_restore
 228                  wrpr                   %g0, %g0, %otherwin
 229
 230                 ldx                     [%g6 + TI_FLAGS], %g3
 231                 wr                      %g0, ASI_AIUP, %asi
 232                 rdpr                    %cwp, %g1
 233                 andcc                   %g3, _TIF_32BIT, %g0
 234                 sub                     %g1, 1, %g1
 235                 bne,pt                  %xcc, user_rtt_fill_32bit
 236                  wrpr                   %g1, %cwp
 237                 ba,a,pt                 %xcc, user_rtt_fill_64bit
 238
 239 user_rtt_fill_fixup:
 240                 rdpr    %cwp, %g1
 241                 add     %g1, 1, %g1
 242                 wrpr    %g1, 0x0, %cwp
 243
 244                 rdpr    %wstate, %g2
 245                 sll     %g2, 3, %g2
 246                 wrpr    %g2, 0x0, %wstate
 247
 248                 /* We know %canrestore and %otherwin are both zero.  */
 249
 250                 sethi   %hi(sparc64_kern_pri_context), %g2
 251                 ldx     [%g2 + %lo(sparc64_kern_pri_context)], %g2
 252                 mov     PRIMARY_CONTEXT, %g1
 253
 254 661:            stxa    %g2, [%g1] ASI_DMMU
 255                 .section .sun4v_1insn_patch, "ax"
 256                 .word   661b
 257                 stxa    %g2, [%g1] ASI_MMU
 258                 .previous
 259
 260                 sethi   %hi(KERNBASE), %g1
 261                 flush   %g1
 262
 263                 or      %g4, FAULT_CODE_WINFIXUP, %g4
 264                 stb     %g4, [%g6 + TI_FAULT_CODE]
 265                 stx     %g5, [%g6 + TI_FAULT_ADDR]
 266
 267                 mov     %g6, %l1
 268                 wrpr    %g0, 0x0, %tl
 269
 270 661:            nop
 271                 .section                .sun4v_1insn_patch, "ax"
 272                 .word                   661b
 273                 SET_GL(0)
 274                 .previous
 275
 276                 wrpr    %g0, RTRAP_PSTATE, %pstate
 277
 278                 mov     %l1, %g6
 279                 ldx     [%g6 + TI_TASK], %g4
 280                 LOAD_PER_CPU_BASE(%g5, %g6, %g1, %g2, %g3)
 281                 call    do_sparc64_fault
 282                  add    %sp, PTREGS_OFF, %o0
 283                 ba,pt   %xcc, rtrap
 284                  nop
 285
 286 user_rtt_pre_restore:
 287                 add                     %g1, 1, %g1
 288                 wrpr                    %g1, 0x0, %cwp
 289
 290 user_rtt_restore:
 291                 restore
 292                 rdpr                    %canrestore, %g1
 293                 wrpr                    %g1, 0x0, %cleanwin
 294                 retry
 295                 nop
 296
 297 kern_rtt:       rdpr                    %canrestore, %g1
 298                 brz,pn                  %g1, kern_rtt_fill
 299                  nop
 300 kern_rtt_restore:
 301                 stw                     %g0, [%sp + PTREGS_OFF + PT_V9_MAGIC]
 302                 restore
 303                 retry
 304
 305 to_kernel:
 306 #ifdef CONFIG_PREEMPT
 307                 ldsw                    [%g6 + TI_PRE_COUNT], %l5
 308                 brnz                    %l5, kern_fpucheck
 309                  ldx                    [%g6 + TI_FLAGS], %l5
 310                 andcc                   %l5, _TIF_NEED_RESCHED, %g0
 311                 be,pt                   %xcc, kern_fpucheck
 312                  nop
 313                 cmp                     %l4, 0
 314                 bne,pn                  %xcc, kern_fpucheck
 315                  nop
 316                 call                    preempt_schedule_irq
 317                  nop
 318                 ba,pt                   %xcc, rtrap
 319 #endif
 320 kern_fpucheck:  ldub                    [%g6 + TI_FPDEPTH], %l5
 321                 brz,pt                  %l5, rt_continue
 322                  srl                    %l5, 1, %o0
 323                 add                     %g6, TI_FPSAVED, %l6
 324                 ldub                    [%l6 + %o0], %l2
 325                 sub                     %l5, 2, %l5
 326
 327                 add                     %g6, TI_GSR, %o1
 328                 andcc                   %l2, (FPRS_FEF|FPRS_DU), %g0
 329                 be,pt                   %icc, 2f
 330                  and                    %l2, FPRS_DL, %l6
 331                 andcc                   %l2, FPRS_FEF, %g0
 332                 be,pn                   %icc, 5f
 333                  sll                    %o0, 3, %o5
 334                 rd                      %fprs, %g1
 335
 336                 wr                      %g1, FPRS_FEF, %fprs
 337                 ldx                     [%o1 + %o5], %g1
 338                 add                     %g6, TI_XFSR, %o1
 339                 sll                     %o0, 8, %o2
 340                 add                     %g6, TI_FPREGS, %o3
 341                 brz,pn                  %l6, 1f
 342                  add                    %g6, TI_FPREGS+0x40, %o4
 343
 344                 membar                  #Sync
 345                 ldda                    [%o3 + %o2] ASI_BLK_P, %f0
 346                 ldda                    [%o4 + %o2] ASI_BLK_P, %f16
 347                 membar                  #Sync
 348 1:              andcc                   %l2, FPRS_DU, %g0
 349                 be,pn                   %icc, 1f
 350                  wr                     %g1, 0, %gsr
 351                 add                     %o2, 0x80, %o2
 352                 membar                  #Sync
 353                 ldda                    [%o3 + %o2] ASI_BLK_P, %f32
 354                 ldda                    [%o4 + %o2] ASI_BLK_P, %f48
 355 1:              membar                  #Sync
 356                 ldx                     [%o1 + %o5], %fsr
 357 2:              stb                     %l5, [%g6 + TI_FPDEPTH]
 358                 ba,pt                   %xcc, rt_continue
 359                  nop
 360 5:              wr                      %g0, FPRS_FEF, %fprs
 361                 sll                     %o0, 8, %o2
 362
 363                 add                     %g6, TI_FPREGS+0x80, %o3
 364                 add                     %g6, TI_FPREGS+0xc0, %o4
 365                 membar                  #Sync
 366                 ldda                    [%o3 + %o2] ASI_BLK_P, %f32
 367                 ldda                    [%o4 + %o2] ASI_BLK_P, %f48
 368                 membar                  #Sync
 369                 wr                      %g0, FPRS_DU, %fprs
 370                 ba,pt                   %xcc, rt_continue
 371                  stb                    %l5, [%g6 + TI_FPDEPTH]