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