arch/ia64/kernel/fsys.S

   1 /*
   2  * This file contains the light-weight system call handlers (fsyscall-handlers).
   3  *
   4  * Copyright (C) 2003 Hewlett-Packard Co
   5  *      David Mosberger-Tang <davidm@hpl.hp.com>
   6  *
   7  * 25-Sep-03 davidm     Implement fsys_rt_sigprocmask().
   8  * 18-Feb-03 louisk     Implement fsys_gettimeofday().
   9  * 28-Feb-03 davidm     Fixed several bugs in fsys_gettimeofday().  Tuned it some more,
  10  *                      probably broke it along the way... ;-)
  11  * 13-Jul-04 clameter   Implement fsys_clock_gettime and revise fsys_gettimeofday to make
  12  *                      it capable of using memory based clocks without falling back to C code.
  13  * 08-Feb-07 Fenghua Yu Implement fsys_getcpu.
  14  *
  15  */
  16
  17 #include <asm/asmmacro.h>
  18 #include <asm/errno.h>
  19 #include <asm/asm-offsets.h>
  20 #include <asm/percpu.h>
  21 #include <asm/thread_info.h>
  22 #include <asm/sal.h>
  23 #include <asm/signal.h>
  24 #include <asm/unistd.h>
  25
  26 #include "entry.h"
  27 #include "paravirt_inst.h"
  28
  29 /*
  30  * See Documentation/ia64/fsys.txt for details on fsyscalls.
  31  *
  32  * On entry to an fsyscall handler:
  33  *   r10        = 0 (i.e., defaults to "successful syscall return")
  34  *   r11        = saved ar.pfs (a user-level value)
  35  *   r15        = system call number
  36  *   r16        = "current" task pointer (in normal kernel-mode, this is in r13)
  37  *   r32-r39    = system call arguments
  38  *   b6         = return address (a user-level value)
  39  *   ar.pfs     = previous frame-state (a user-level value)
  40  *   PSR.be     = cleared to zero (i.e., little-endian byte order is in effect)
  41  *   all other registers may contain values passed in from user-mode
  42  *
  43  * On return from an fsyscall handler:
  44  *   r11        = saved ar.pfs (as passed into the fsyscall handler)
  45  *   r15        = system call number (as passed into the fsyscall handler)
  46  *   r32-r39    = system call arguments (as passed into the fsyscall handler)
  47  *   b6         = return address (as passed into the fsyscall handler)
  48  *   ar.pfs     = previous frame-state (as passed into the fsyscall handler)
  49  */
  50
  51 ENTRY(fsys_ni_syscall)
  52         .prologue
  53         .altrp b6
  54         .body
  55         mov r8=ENOSYS
  56         mov r10=-1
  57         FSYS_RETURN
  58 END(fsys_ni_syscall)
  59
  60 ENTRY(fsys_getpid)
  61         .prologue
  62         .altrp b6
  63         .body
  64         add r17=IA64_TASK_GROUP_LEADER_OFFSET,r16
  65         ;;
  66         ld8 r17=[r17]                           // r17 = current->group_leader
  67         add r9=TI_FLAGS+IA64_TASK_SIZE,r16
  68         ;;
  69         ld4 r9=[r9]
  70         add r17=IA64_TASK_TGIDLINK_OFFSET,r17
  71         ;;
  72         and r9=TIF_ALLWORK_MASK,r9
  73         ld8 r17=[r17]                           // r17 = current->group_leader->pids[PIDTYPE_PID].pid
  74         ;;
  75         add r8=IA64_PID_LEVEL_OFFSET,r17
  76         ;;
  77         ld4 r8=[r8]                             // r8 = pid->level
  78         add r17=IA64_PID_UPID_OFFSET,r17        // r17 = &pid->numbers[0]
  79         ;;
  80         shl r8=r8,IA64_UPID_SHIFT
  81         ;;
  82         add r17=r17,r8                          // r17 = &pid->numbers[pid->level]
  83         ;;
  84         ld4 r8=[r17]                            // r8 = pid->numbers[pid->level].nr
  85         ;;
  86         mov r17=0
  87         ;;
  88         cmp.ne p8,p0=0,r9
  89 (p8)    br.spnt.many fsys_fallback_syscall
  90         FSYS_RETURN
  91 END(fsys_getpid)
  92
  93 ENTRY(fsys_getppid)
  94         .prologue
  95         .altrp b6
  96         .body
  97         add r17=IA64_TASK_GROUP_LEADER_OFFSET,r16
  98         ;;
  99         ld8 r17=[r17]                           // r17 = current->group_leader
 100         add r9=TI_FLAGS+IA64_TASK_SIZE,r16
 101         ;;
 102
 103         ld4 r9=[r9]
 104         add r17=IA64_TASK_REAL_PARENT_OFFSET,r17 // r17 = &current->group_leader->real_parent
 105         ;;
 106         and r9=TIF_ALLWORK_MASK,r9
 107
 108 1:      ld8 r18=[r17]                           // r18 = current->group_leader->real_parent
 109         ;;
 110         cmp.ne p8,p0=0,r9
 111         add r8=IA64_TASK_TGID_OFFSET,r18        // r8 = &current->group_leader->real_parent->tgid
 112         ;;
 113
 114         /*
 115          * The .acq is needed to ensure that the read of tgid has returned its data before
 116          * we re-check "real_parent".
 117          */
 118         ld4.acq r8=[r8]                         // r8 = current->group_leader->real_parent->tgid
 119 #ifdef CONFIG_SMP
 120         /*
 121          * Re-read current->group_leader->real_parent.
 122          */
 123         ld8 r19=[r17]                           // r19 = current->group_leader->real_parent
 124 (p8)    br.spnt.many fsys_fallback_syscall
 125         ;;
 126         cmp.ne p6,p0=r18,r19                    // did real_parent change?
 127         mov r19=0                       // i must not leak kernel bits...
 128 (p6)    br.cond.spnt.few 1b                     // yes -> redo the read of tgid and the check
 129         ;;
 130         mov r17=0                       // i must not leak kernel bits...
 131         mov r18=0                       // i must not leak kernel bits...
 132 #else
 133         mov r17=0                       // i must not leak kernel bits...
 134         mov r18=0                       // i must not leak kernel bits...
 135         mov r19=0                       // i must not leak kernel bits...
 136 #endif
 137         FSYS_RETURN
 138 END(fsys_getppid)
 139
 140 ENTRY(fsys_set_tid_address)
 141         .prologue
 142         .altrp b6
 143         .body
 144         add r9=TI_FLAGS+IA64_TASK_SIZE,r16
 145         add r17=IA64_TASK_TGIDLINK_OFFSET,r16
 146         ;;
 147         ld4 r9=[r9]
 148         tnat.z p6,p7=r32                // check argument register for being NaT
 149         ld8 r17=[r17]                           // r17 = current->pids[PIDTYPE_PID].pid
 150         ;;
 151         and r9=TIF_ALLWORK_MASK,r9
 152         add r8=IA64_PID_LEVEL_OFFSET,r17
 153         add r18=IA64_TASK_CLEAR_CHILD_TID_OFFSET,r16
 154         ;;
 155         ld4 r8=[r8]                             // r8 = pid->level
 156         add r17=IA64_PID_UPID_OFFSET,r17        // r17 = &pid->numbers[0]
 157         ;;
 158         shl r8=r8,IA64_UPID_SHIFT
 159         ;;
 160         add r17=r17,r8                          // r17 = &pid->numbers[pid->level]
 161         ;;
 162         ld4 r8=[r17]                            // r8 = pid->numbers[pid->level].nr
 163         ;;
 164         cmp.ne p8,p0=0,r9
 165         mov r17=-1
 166         ;;
 167 (p6)    st8 [r18]=r32
 168 (p7)    st8 [r18]=r17
 169 (p8)    br.spnt.many fsys_fallback_syscall
 170         ;;
 171         mov r17=0                       // i must not leak kernel bits...
 172         mov r18=0                       // i must not leak kernel bits...
 173         FSYS_RETURN
 174 END(fsys_set_tid_address)
 175
 176 #if IA64_GTOD_SEQ_OFFSET !=0
 177 #error fsys_gettimeofday incompatible with changes to struct fsyscall_gtod_data_t
 178 #endif
 179 #if IA64_ITC_JITTER_OFFSET !=0
 180 #error fsys_gettimeofday incompatible with changes to struct itc_jitter_data_t
 181 #endif
 182 #define CLOCK_REALTIME 0
 183 #define CLOCK_MONOTONIC 1
 184 #define CLOCK_DIVIDE_BY_1000 0x4000
 185 #define CLOCK_ADD_MONOTONIC 0x8000
 186
 187 ENTRY(fsys_gettimeofday)
 188         .prologue
 189         .altrp b6
 190         .body
 191         mov r31 = r32
 192         tnat.nz p6,p0 = r33             // guard against NaT argument
 193 (p6)    br.cond.spnt.few .fail_einval
 194         mov r30 = CLOCK_DIVIDE_BY_1000
 195         ;;
 196 .gettime:
 197         // Register map
 198         // Incoming r31 = pointer to address where to place result
 199         //          r30 = flags determining how time is processed
 200         // r2,r3 = temp r4-r7 preserved
 201         // r8 = result nanoseconds
 202         // r9 = result seconds
 203         // r10 = temporary storage for clock difference
 204         // r11 = preserved: saved ar.pfs
 205         // r12 = preserved: memory stack
 206         // r13 = preserved: thread pointer
 207         // r14 = address of mask / mask value
 208         // r15 = preserved: system call number
 209         // r16 = preserved: current task pointer
 210         // r17 = (not used)
 211         // r18 = (not used)
 212         // r19 = address of itc_lastcycle
 213         // r20 = struct fsyscall_gtod_data (= address of gtod_lock.sequence)
 214         // r21 = address of mmio_ptr
 215         // r22 = address of wall_time or monotonic_time
 216         // r23 = address of shift / value
 217         // r24 = address mult factor / cycle_last value
 218         // r25 = itc_lastcycle value
 219         // r26 = address clocksource cycle_last
 220         // r27 = (not used)
 221         // r28 = sequence number at the beginning of critcal section
 222         // r29 = address of itc_jitter
 223         // r30 = time processing flags / memory address
 224         // r31 = pointer to result
 225         // Predicates
 226         // p6,p7 short term use
 227         // p8 = timesource ar.itc
 228         // p9 = timesource mmio64
 229         // p10 = timesource mmio32 - not used
 230         // p11 = timesource not to be handled by asm code
 231         // p12 = memory time source ( = p9 | p10) - not used
 232         // p13 = do cmpxchg with itc_lastcycle
 233         // p14 = Divide by 1000
 234         // p15 = Add monotonic
 235         //
 236         // Note that instructions are optimized for McKinley. McKinley can
 237         // process two bundles simultaneously and therefore we continuously
 238         // try to feed the CPU two bundles and then a stop.
 239
 240         add r2 = TI_FLAGS+IA64_TASK_SIZE,r16
 241         tnat.nz p6,p0 = r31             // guard against Nat argument
 242 (p6)    br.cond.spnt.few .fail_einval
 243         movl r20 = fsyscall_gtod_data // load fsyscall gettimeofday data address
 244         ;;
 245         ld4 r2 = [r2]                   // process work pending flags
 246         movl r29 = itc_jitter_data      // itc_jitter
 247         add r22 = IA64_GTOD_WALL_TIME_OFFSET,r20        // wall_time
 248         add r21 = IA64_CLKSRC_MMIO_OFFSET,r20
 249         mov pr = r30,0xc000     // Set predicates according to function
 250         ;;
 251         and r2 = TIF_ALLWORK_MASK,r2
 252         add r19 = IA64_ITC_LASTCYCLE_OFFSET,r29
 253 (p15)   add r22 = IA64_GTOD_MONO_TIME_OFFSET,r20        // monotonic_time
 254         ;;
 255         add r26 = IA64_CLKSRC_CYCLE_LAST_OFFSET,r20     // clksrc_cycle_last
 256         cmp.ne p6, p0 = 0, r2   // Fallback if work is scheduled
 257 (p6)    br.cond.spnt.many fsys_fallback_syscall
 258         ;;
 259         // Begin critical section
 260 .time_redo:
 261         ld4.acq r28 = [r20]     // gtod_lock.sequence, Must take first
 262         ;;
 263         and r28 = ~1,r28        // And make sequence even to force retry if odd
 264         ;;
 265         ld8 r30 = [r21]         // clocksource->mmio_ptr
 266         add r24 = IA64_CLKSRC_MULT_OFFSET,r20
 267         ld4 r2 = [r29]          // itc_jitter value
 268         add r23 = IA64_CLKSRC_SHIFT_OFFSET,r20
 269         add r14 = IA64_CLKSRC_MASK_OFFSET,r20
 270         ;;
 271         ld4 r3 = [r24]          // clocksource mult value
 272         ld8 r14 = [r14]         // clocksource mask value
 273         cmp.eq p8,p9 = 0,r30    // use cpu timer if no mmio_ptr
 274         ;;
 275         setf.sig f7 = r3        // Setup for mult scaling of counter
 276 (p8)    cmp.ne p13,p0 = r2,r0   // need itc_jitter compensation, set p13
 277         ld4 r23 = [r23]         // clocksource shift value
 278         ld8 r24 = [r26]         // get clksrc_cycle_last value
 279 (p9)    cmp.eq p13,p0 = 0,r30   // if mmio_ptr, clear p13 jitter control
 280         ;;
 281         .pred.rel.mutex p8,p9
 282         MOV_FROM_ITC(p8, p6, r2, r10)   // CPU_TIMER. 36 clocks latency!!!
 283 (p9)    ld8 r2 = [r30]          // MMIO_TIMER. Could also have latency issues..
 284 (p13)   ld8 r25 = [r19]         // get itc_lastcycle value
 285         ld8 r9 = [r22],IA64_TIMESPEC_TV_NSEC_OFFSET     // tv_sec
 286         ;;
 287         ld8 r8 = [r22],-IA64_TIMESPEC_TV_NSEC_OFFSET    // tv_nsec
 288 (p13)   sub r3 = r25,r2         // Diff needed before comparison (thanks davidm)
 289         ;;
 290 (p13)   cmp.gt.unc p6,p7 = r3,r0 // check if it is less than last. p6,p7 cleared
 291         sub r10 = r2,r24        // current_cycle - last_cycle
 292         ;;
 293 (p6)    sub r10 = r25,r24       // time we got was less than last_cycle
 294 (p7)    mov ar.ccv = r25        // more than last_cycle. Prep for cmpxchg
 295         ;;
 296 (p7)    cmpxchg8.rel r3 = [r19],r2,ar.ccv
 297         ;;
 298 (p7)    cmp.ne p7,p0 = r25,r3   // if cmpxchg not successful
 299         ;;
 300 (p7)    sub r10 = r3,r24        // then use new last_cycle instead
 301         ;;
 302         and r10 = r10,r14       // Apply mask
 303         ;;
 304         setf.sig f8 = r10
 305         nop.i 123
 306         ;;
 307         // fault check takes 5 cycles and we have spare time
 308 EX(.fail_efault, probe.w.fault r31, 3)
 309         xmpy.l f8 = f8,f7       // nsec_per_cyc*(counter-last_counter)
 310         ;;
 311         getf.sig r2 = f8
 312         mf
 313         ;;
 314         ld4 r10 = [r20]         // gtod_lock.sequence
 315         shr.u r2 = r2,r23       // shift by factor
 316         ;;
 317         add r8 = r8,r2          // Add xtime.nsecs
 318         cmp4.ne p7,p0 = r28,r10
 319 (p7)    br.cond.dpnt.few .time_redo     // sequence number changed, redo
 320         // End critical section.
 321         // Now r8=tv->tv_nsec and r9=tv->tv_sec
 322         mov r10 = r0
 323         movl r2 = 1000000000
 324         add r23 = IA64_TIMESPEC_TV_NSEC_OFFSET, r31
 325 (p14)   movl r3 = 2361183241434822607   // Prep for / 1000 hack
 326         ;;
 327 .time_normalize:
 328         mov r21 = r8
 329         cmp.ge p6,p0 = r8,r2
 330 (p14)   shr.u r20 = r8, 3 // We can repeat this if necessary just wasting time
 331         ;;
 332 (p14)   setf.sig f8 = r20
 333 (p6)    sub r8 = r8,r2
 334 (p6)    add r9 = 1,r9           // two nops before the branch.
 335 (p14)   setf.sig f7 = r3        // Chances for repeats are 1 in 10000 for gettod
 336 (p6)    br.cond.dpnt.few .time_normalize
 337         ;;
 338         // Divided by 8 though shift. Now divide by 125
 339         // The compiler was able to do that with a multiply
 340         // and a shift and we do the same
 341 EX(.fail_efault, probe.w.fault r23, 3)  // This also costs 5 cycles
 342 (p14)   xmpy.hu f8 = f8, f7             // xmpy has 5 cycles latency so use it
 343         ;;
 344 (p14)   getf.sig r2 = f8
 345         ;;
 346         mov r8 = r0
 347 (p14)   shr.u r21 = r2, 4
 348         ;;
 349 EX(.fail_efault, st8 [r31] = r9)
 350 EX(.fail_efault, st8 [r23] = r21)
 351         FSYS_RETURN
 352 .fail_einval:
 353         mov r8 = EINVAL
 354         mov r10 = -1
 355         FSYS_RETURN
 356 .fail_efault:
 357         mov r8 = EFAULT
 358         mov r10 = -1
 359         FSYS_RETURN
 360 END(fsys_gettimeofday)
 361
 362 ENTRY(fsys_clock_gettime)
 363         .prologue
 364         .altrp b6
 365         .body
 366         cmp4.ltu p6, p0 = CLOCK_MONOTONIC, r32
 367         // Fallback if this is not CLOCK_REALTIME or CLOCK_MONOTONIC
 368 (p6)    br.spnt.few fsys_fallback_syscall
 369         mov r31 = r33
 370         shl r30 = r32,15
 371         br.many .gettime
 372 END(fsys_clock_gettime)
 373
 374 /*
 375  * long fsys_rt_sigprocmask (int how, sigset_t *set, sigset_t *oset, size_t sigsetsize).
 376  */
 377 #if _NSIG_WORDS != 1
 378 # error Sorry, fsys_rt_sigprocmask() needs to be updated for _NSIG_WORDS != 1.
 379 #endif
 380 ENTRY(fsys_rt_sigprocmask)
 381         .prologue
 382         .altrp b6
 383         .body
 384
 385         add r2=IA64_TASK_BLOCKED_OFFSET,r16
 386         add r9=TI_FLAGS+IA64_TASK_SIZE,r16
 387         cmp4.ltu p6,p0=SIG_SETMASK,r32
 388
 389         cmp.ne p15,p0=r0,r34                    // oset != NULL?
 390         tnat.nz p8,p0=r34
 391         add r31=IA64_TASK_SIGHAND_OFFSET,r16
 392         ;;
 393         ld8 r3=[r2]                             // read/prefetch current->blocked
 394         ld4 r9=[r9]
 395         tnat.nz.or p6,p0=r35
 396
 397         cmp.ne.or p6,p0=_NSIG_WORDS*8,r35
 398         tnat.nz.or p6,p0=r32
 399 (p6)    br.spnt.few .fail_einval                // fail with EINVAL
 400         ;;
 401 #ifdef CONFIG_SMP
 402         ld8 r31=[r31]                           // r31 <- current->sighand
 403 #endif
 404         and r9=TIF_ALLWORK_MASK,r9
 405         tnat.nz.or p8,p0=r33
 406         ;;
 407         cmp.ne p7,p0=0,r9
 408         cmp.eq p6,p0=r0,r33                     // set == NULL?
 409         add r31=IA64_SIGHAND_SIGLOCK_OFFSET,r31 // r31 <- current->sighand->siglock
 410 (p8)    br.spnt.few .fail_efault                // fail with EFAULT
 411 (p7)    br.spnt.many fsys_fallback_syscall      // got pending kernel work...
 412 (p6)    br.dpnt.many .store_mask                // -> short-circuit to just reading the signal mask
 413
 414         /* Argh, we actually have to do some work and _update_ the signal mask: */
 415
 416 EX(.fail_efault, probe.r.fault r33, 3)          // verify user has read-access to *set
 417 EX(.fail_efault, ld8 r14=[r33])                 // r14 <- *set
 418         mov r17=(1 << (SIGKILL - 1)) | (1 << (SIGSTOP - 1))
 419         ;;
 420
 421         RSM_PSR_I(p0, r18, r19)                 // mask interrupt delivery
 422         andcm r14=r14,r17                       // filter out SIGKILL & SIGSTOP
 423         mov r8=EINVAL                   // default to EINVAL
 424
 425 #ifdef CONFIG_SMP
 426         // __ticket_spin_trylock(r31)
 427         ld4 r17=[r31]
 428         ;;
 429         mov.m ar.ccv=r17
 430         extr.u r9=r17,17,15
 431         adds r19=1,r17
 432         extr.u r18=r17,0,15
 433         ;;
 434         cmp.eq p6,p7=r9,r18
 435         ;;
 436 (p6)    cmpxchg4.acq r9=[r31],r19,ar.ccv
 437 (p6)    dep.z r20=r19,1,15              // next serving ticket for unlock
 438 (p7)    br.cond.spnt.many .lock_contention
 439         ;;
 440         cmp4.eq p0,p7=r9,r17
 441         adds r31=2,r31
 442 (p7)    br.cond.spnt.many .lock_contention
 443         ld8 r3=[r2]                     // re-read current->blocked now that we hold the lock
 444         ;;
 445 #else
 446         ld8 r3=[r2]                     // re-read current->blocked now that we hold the lock
 447 #endif
 448         add r18=IA64_TASK_PENDING_OFFSET+IA64_SIGPENDING_SIGNAL_OFFSET,r16
 449         add r19=IA64_TASK_SIGNAL_OFFSET,r16
 450         cmp4.eq p6,p0=SIG_BLOCK,r32
 451         ;;
 452         ld8 r19=[r19]                   // r19 <- current->signal
 453         cmp4.eq p7,p0=SIG_UNBLOCK,r32
 454         cmp4.eq p8,p0=SIG_SETMASK,r32
 455         ;;
 456         ld8 r18=[r18]                   // r18 <- current->pending.signal
 457         .pred.rel.mutex p6,p7,p8
 458 (p6)    or r14=r3,r14                   // SIG_BLOCK
 459 (p7)    andcm r14=r3,r14                // SIG_UNBLOCK
 460
 461 (p8)    mov r14=r14                     // SIG_SETMASK
 462 (p6)    mov r8=0                        // clear error code
 463         // recalc_sigpending()
 464         add r17=IA64_SIGNAL_GROUP_STOP_COUNT_OFFSET,r19
 465
 466         add r19=IA64_SIGNAL_SHARED_PENDING_OFFSET+IA64_SIGPENDING_SIGNAL_OFFSET,r19
 467         ;;
 468         ld4 r17=[r17]           // r17 <- current->signal->group_stop_count
 469 (p7)    mov r8=0                // clear error code
 470
 471         ld8 r19=[r19]           // r19 <- current->signal->shared_pending
 472         ;;
 473         cmp4.gt p6,p7=r17,r0    // p6/p7 <- (current->signal->group_stop_count > 0)?
 474 (p8)    mov r8=0                // clear error code
 475
 476         or r18=r18,r19          // r18 <- current->pending | current->signal->shared_pending
 477         ;;
 478         // r18 <- (current->pending | current->signal->shared_pending) & ~current->blocked:
 479         andcm r18=r18,r14
 480         add r9=TI_FLAGS+IA64_TASK_SIZE,r16
 481         ;;
 482
 483 (p7)    cmp.ne.or.andcm p6,p7=r18,r0            // p6/p7 <- signal pending
 484         mov r19=0                                       // i must not leak kernel bits...
 485 (p6)    br.cond.dpnt.many .sig_pending
 486         ;;
 487
 488 1:      ld4 r17=[r9]                            // r17 <- current->thread_info->flags
 489         ;;
 490         mov ar.ccv=r17
 491         and r18=~_TIF_SIGPENDING,r17            // r18 <- r17 & ~(1 << TIF_SIGPENDING)
 492         ;;
 493
 494         st8 [r2]=r14                            // update current->blocked with new mask
 495         cmpxchg4.acq r8=[r9],r18,ar.ccv         // current->thread_info->flags <- r18
 496         ;;
 497         cmp.ne p6,p0=r17,r8                     // update failed?
 498 (p6)    br.cond.spnt.few 1b                     // yes -> retry
 499
 500 #ifdef CONFIG_SMP
 501         // __ticket_spin_unlock(r31)
 502         st2.rel [r31]=r20
 503         mov r20=0                                       // i must not leak kernel bits...
 504 #endif
 505         SSM_PSR_I(p0, p9, r31)
 506         ;;
 507
 508         srlz.d                                  // ensure psr.i is set again
 509         mov r18=0                                       // i must not leak kernel bits...
 510
 511 .store_mask:
 512 EX(.fail_efault, (p15) probe.w.fault r34, 3)    // verify user has write-access to *oset
 513 EX(.fail_efault, (p15) st8 [r34]=r3)
 514         mov r2=0                                        // i must not leak kernel bits...
 515         mov r3=0                                        // i must not leak kernel bits...
 516         mov r8=0                                // return 0
 517         mov r9=0                                        // i must not leak kernel bits...
 518         mov r14=0                                       // i must not leak kernel bits...
 519         mov r17=0                                       // i must not leak kernel bits...
 520         mov r31=0                                       // i must not leak kernel bits...
 521         FSYS_RETURN
 522
 523 .sig_pending:
 524 #ifdef CONFIG_SMP
 525         // __ticket_spin_unlock(r31)
 526         st2.rel [r31]=r20                       // release the lock
 527 #endif
 528         SSM_PSR_I(p0, p9, r17)
 529         ;;
 530         srlz.d
 531         br.sptk.many fsys_fallback_syscall      // with signal pending, do the heavy-weight syscall
 532
 533 #ifdef CONFIG_SMP
 534 .lock_contention:
 535         /* Rather than spinning here, fall back on doing a heavy-weight syscall.  */
 536         SSM_PSR_I(p0, p9, r17)
 537         ;;
 538         srlz.d
 539         br.sptk.many fsys_fallback_syscall
 540 #endif
 541 END(fsys_rt_sigprocmask)
 542
 543 /*
 544  * fsys_getcpu doesn't use the third parameter in this implementation. It reads
 545  * current_thread_info()->cpu and corresponding node in cpu_to_node_map.
 546  */
 547 ENTRY(fsys_getcpu)
 548         .prologue
 549         .altrp b6
 550         .body
 551         ;;
 552         add r2=TI_FLAGS+IA64_TASK_SIZE,r16
 553         tnat.nz p6,p0 = r32                     // guard against NaT argument
 554         add r3=TI_CPU+IA64_TASK_SIZE,r16
 555         ;;
 556         ld4 r3=[r3]                             // M r3 = thread_info->cpu
 557         ld4 r2=[r2]                             // M r2 = thread_info->flags
 558 (p6)    br.cond.spnt.few .fail_einval           // B
 559         ;;
 560         tnat.nz p7,p0 = r33                     // I guard against NaT argument
 561 (p7)    br.cond.spnt.few .fail_einval           // B
 562 #ifdef CONFIG_NUMA
 563         movl r17=cpu_to_node_map
 564         ;;
 565 EX(.fail_efault, probe.w.fault r32, 3)          // M This takes 5 cycles
 566 EX(.fail_efault, probe.w.fault r33, 3)          // M This takes 5 cycles
 567         shladd r18=r3,1,r17
 568         ;;
 569         ld2 r20=[r18]                           // r20 = cpu_to_node_map[cpu]
 570         and r2 = TIF_ALLWORK_MASK,r2
 571         ;;
 572         cmp.ne p8,p0=0,r2
 573 (p8)    br.spnt.many fsys_fallback_syscall
 574         ;;
 575         ;;
 576 EX(.fail_efault, st4 [r32] = r3)
 577 EX(.fail_efault, st2 [r33] = r20)
 578         mov r8=0
 579         ;;
 580 #else
 581 EX(.fail_efault, probe.w.fault r32, 3)          // M This takes 5 cycles
 582 EX(.fail_efault, probe.w.fault r33, 3)          // M This takes 5 cycles
 583         and r2 = TIF_ALLWORK_MASK,r2
 584         ;;
 585         cmp.ne p8,p0=0,r2
 586 (p8)    br.spnt.many fsys_fallback_syscall
 587         ;;
 588 EX(.fail_efault, st4 [r32] = r3)
 589 EX(.fail_efault, st2 [r33] = r0)
 590         mov r8=0
 591         ;;
 592 #endif
 593         FSYS_RETURN
 594 END(fsys_getcpu)
 595
 596 ENTRY(fsys_fallback_syscall)
 597         .prologue
 598         .altrp b6
 599         .body
 600         /*
 601          * We only get here from light-weight syscall handlers.  Thus, we already
 602          * know that r15 contains a valid syscall number.  No need to re-check.
 603          */
 604         adds r17=-1024,r15
 605         movl r14=sys_call_table
 606         ;;
 607         RSM_PSR_I(p0, r26, r27)
 608         shladd r18=r17,3,r14
 609         ;;
 610         ld8 r18=[r18]                           // load normal (heavy-weight) syscall entry-point
 611         MOV_FROM_PSR(p0, r29, r26)              // read psr (12 cyc load latency)
 612         mov r27=ar.rsc
 613         mov r21=ar.fpsr
 614         mov r26=ar.pfs
 615 END(fsys_fallback_syscall)
 616         /* FALL THROUGH */
 617 GLOBAL_ENTRY(paravirt_fsys_bubble_down)
 618         .prologue
 619         .altrp b6
 620         .body
 621         /*
 622          * We get here for syscalls that don't have a lightweight
 623          * handler.  For those, we need to bubble down into the kernel
 624          * and that requires setting up a minimal pt_regs structure,
 625          * and initializing the CPU state more or less as if an
 626          * interruption had occurred.  To make syscall-restarts work,
 627          * we setup pt_regs such that cr_iip points to the second
 628          * instruction in syscall_via_break.  Decrementing the IP
 629          * hence will restart the syscall via break and not
 630          * decrementing IP will return us to the caller, as usual.
 631          * Note that we preserve the value of psr.pp rather than
 632          * initializing it from dcr.pp.  This makes it possible to
 633          * distinguish fsyscall execution from other privileged
 634          * execution.
 635          *
 636          * On entry:
 637          *      - normal fsyscall handler register usage, except
 638          *        that we also have:
 639          *      - r18: address of syscall entry point
 640          *      - r21: ar.fpsr
 641          *      - r26: ar.pfs
 642          *      - r27: ar.rsc
 643          *      - r29: psr
 644          *
 645          * We used to clear some PSR bits here but that requires slow
 646          * serialization.  Fortuntely, that isn't really necessary.
 647          * The rationale is as follows: we used to clear bits
 648          * ~PSR_PRESERVED_BITS in PSR.L.  Since
 649          * PSR_PRESERVED_BITS==PSR.{UP,MFL,MFH,PK,DT,PP,SP,RT,IC}, we
 650          * ended up clearing PSR.{BE,AC,I,DFL,DFH,DI,DB,SI,TB}.
 651          * However,
 652          *
 653          * PSR.BE : already is turned off in __kernel_syscall_via_epc()
 654          * PSR.AC : don't care (kernel normally turns PSR.AC on)
 655          * PSR.I  : already turned off by the time paravirt_fsys_bubble_down gets
 656          *          invoked
 657          * PSR.DFL: always 0 (kernel never turns it on)
 658          * PSR.DFH: don't care --- kernel never touches f32-f127 on its own
 659          *          initiative
 660          * PSR.DI : always 0 (kernel never turns it on)
 661          * PSR.SI : always 0 (kernel never turns it on)
 662          * PSR.DB : don't care --- kernel never enables kernel-level
 663          *          breakpoints
 664          * PSR.TB : must be 0 already; if it wasn't zero on entry to
 665          *          __kernel_syscall_via_epc, the branch to paravirt_fsys_bubble_down
 666          *          will trigger a taken branch; the taken-trap-handler then
 667          *          converts the syscall into a break-based system-call.
 668          */
 669         /*
 670          * Reading psr.l gives us only bits 0-31, psr.it, and psr.mc.
 671          * The rest we have to synthesize.
 672          */
 673 #       define PSR_ONE_BITS             ((3 << IA64_PSR_CPL0_BIT)       \
 674                                          | (0x1 << IA64_PSR_RI_BIT)     \
 675                                          | IA64_PSR_BN | IA64_PSR_I)
 676
 677         invala                                  // M0|1
 678         movl r14=ia64_ret_from_syscall          // X
 679
 680         nop.m 0
 681         movl r28=__kernel_syscall_via_break     // X    create cr.iip
 682         ;;
 683
 684         mov r2=r16                              // A    get task addr to addl-addressable register
 685         adds r16=IA64_TASK_THREAD_ON_USTACK_OFFSET,r16 // A
 686         mov r31=pr                              // I0   save pr (2 cyc)
 687         ;;
 688         st1 [r16]=r0                            // M2|3 clear current->thread.on_ustack flag
 689         addl r22=IA64_RBS_OFFSET,r2             // A    compute base of RBS
 690         add r3=TI_FLAGS+IA64_TASK_SIZE,r2       // A
 691         ;;
 692         ld4 r3=[r3]                             // M0|1 r3 = current_thread_info()->flags
 693         lfetch.fault.excl.nt1 [r22]             // M0|1 prefetch register backing-store
 694         nop.i 0
 695         ;;
 696         mov ar.rsc=0                            // M2   set enforced lazy mode, pl 0, LE, loadrs=0
 697 #ifdef CONFIG_VIRT_CPU_ACCOUNTING
 698         MOV_FROM_ITC(p0, p6, r30, r23)          // M    get cycle for accounting
 699 #else
 700         nop.m 0
 701 #endif
 702         nop.i 0
 703         ;;
 704         mov r23=ar.bspstore                     // M2 (12 cyc) save ar.bspstore
 705         mov.m r24=ar.rnat                       // M2 (5 cyc) read ar.rnat (dual-issues!)
 706         nop.i 0
 707         ;;
 708         mov ar.bspstore=r22                     // M2 (6 cyc) switch to kernel RBS
 709         movl r8=PSR_ONE_BITS                    // X
 710         ;;
 711         mov r25=ar.unat                         // M2 (5 cyc) save ar.unat
 712         mov r19=b6                              // I0   save b6 (2 cyc)
 713         mov r20=r1                              // A    save caller's gp in r20
 714         ;;
 715         or r29=r8,r29                           // A    construct cr.ipsr value to save
 716         mov b6=r18                              // I0   copy syscall entry-point to b6 (7 cyc)
 717         addl r1=IA64_STK_OFFSET-IA64_PT_REGS_SIZE,r2 // A compute base of memory stack
 718
 719         mov r18=ar.bsp                          // M2   save (kernel) ar.bsp (12 cyc)
 720         cmp.ne pKStk,pUStk=r0,r0                // A    set pKStk <- 0, pUStk <- 1
 721         br.call.sptk.many b7=ia64_syscall_setup // B
 722         ;;
 723 #ifdef CONFIG_VIRT_CPU_ACCOUNTING
 724         // mov.m r30=ar.itc is called in advance
 725         add r16=TI_AC_STAMP+IA64_TASK_SIZE,r2
 726         add r17=TI_AC_LEAVE+IA64_TASK_SIZE,r2
 727         ;;
 728         ld8 r18=[r16],TI_AC_STIME-TI_AC_STAMP   // time at last check in kernel
 729         ld8 r19=[r17],TI_AC_UTIME-TI_AC_LEAVE   // time at leave kernel
 730         ;;
 731         ld8 r20=[r16],TI_AC_STAMP-TI_AC_STIME   // cumulated stime
 732         ld8 r21=[r17]                           // cumulated utime
 733         sub r22=r19,r18                         // stime before leave kernel
 734         ;;
 735         st8 [r16]=r30,TI_AC_STIME-TI_AC_STAMP   // update stamp
 736         sub r18=r30,r19                         // elapsed time in user mode
 737         ;;
 738         add r20=r20,r22                         // sum stime
 739         add r21=r21,r18                         // sum utime
 740         ;;
 741         st8 [r16]=r20                           // update stime
 742         st8 [r17]=r21                           // update utime
 743         ;;
 744 #endif
 745         mov ar.rsc=0x3                          // M2   set eager mode, pl 0, LE, loadrs=0
 746         mov rp=r14                              // I0   set the real return addr
 747         and r3=_TIF_SYSCALL_TRACEAUDIT,r3       // A
 748         ;;
 749         SSM_PSR_I(p0, p6, r22)                  // M2   we're on kernel stacks now, reenable irqs
 750         cmp.eq p8,p0=r3,r0                      // A
 751 (p10)   br.cond.spnt.many ia64_ret_from_syscall // B    return if bad call-frame or r15 is a NaT
 752
 753         nop.m 0
 754 (p8)    br.call.sptk.many b6=b6                 // B    (ignore return address)
 755         br.cond.spnt ia64_trace_syscall         // B
 756 END(paravirt_fsys_bubble_down)
 757
 758         .rodata
 759         .align 8
 760         .globl paravirt_fsyscall_table
 761
 762         data8 paravirt_fsys_bubble_down
 763 paravirt_fsyscall_table:
 764         data8 fsys_ni_syscall
 765         data8 0                         // exit                 // 1025
 766         data8 0                         // read
 767         data8 0                         // write
 768         data8 0                         // open
 769         data8 0                         // close
 770         data8 0                         // creat                // 1030
 771         data8 0                         // link
 772         data8 0                         // unlink
 773         data8 0                         // execve
 774         data8 0                         // chdir
 775         data8 0                         // fchdir               // 1035
 776         data8 0                         // utimes
 777         data8 0                         // mknod
 778         data8 0                         // chmod
 779         data8 0                         // chown
 780         data8 0                         // lseek                // 1040
 781         data8 fsys_getpid               // getpid
 782         data8 fsys_getppid              // getppid
 783         data8 0                         // mount
 784         data8 0                         // umount
 785         data8 0                         // setuid               // 1045
 786         data8 0                         // getuid
 787         data8 0                         // geteuid
 788         data8 0                         // ptrace
 789         data8 0                         // access
 790         data8 0                         // sync                 // 1050
 791         data8 0                         // fsync
 792         data8 0                         // fdatasync
 793         data8 0                         // kill
 794         data8 0                         // rename
 795         data8 0                         // mkdir                // 1055
 796         data8 0                         // rmdir
 797         data8 0                         // dup
 798         data8 0                         // pipe
 799         data8 0                         // times
 800         data8 0                         // brk                  // 1060
 801         data8 0                         // setgid
 802         data8 0                         // getgid
 803         data8 0                         // getegid
 804         data8 0                         // acct
 805         data8 0                         // ioctl                // 1065
 806         data8 0                         // fcntl
 807         data8 0                         // umask
 808         data8 0                         // chroot
 809         data8 0                         // ustat
 810         data8 0                         // dup2                 // 1070
 811         data8 0                         // setreuid
 812         data8 0                         // setregid
 813         data8 0                         // getresuid
 814         data8 0                         // setresuid
 815         data8 0                         // getresgid            // 1075
 816         data8 0                         // setresgid
 817         data8 0                         // getgroups
 818         data8 0                         // setgroups
 819         data8 0                         // getpgid
 820         data8 0                         // setpgid              // 1080
 821         data8 0                         // setsid
 822         data8 0                         // getsid
 823         data8 0                         // sethostname
 824         data8 0                         // setrlimit
 825         data8 0                         // getrlimit            // 1085
 826         data8 0                         // getrusage
 827         data8 fsys_gettimeofday         // gettimeofday
 828         data8 0                         // settimeofday
 829         data8 0                         // select
 830         data8 0                         // poll                 // 1090
 831         data8 0                         // symlink
 832         data8 0                         // readlink
 833         data8 0                         // uselib
 834         data8 0                         // swapon
 835         data8 0                         // swapoff              // 1095
 836         data8 0                         // reboot
 837         data8 0                         // truncate
 838         data8 0                         // ftruncate
 839         data8 0                         // fchmod
 840         data8 0                         // fchown               // 1100
 841         data8 0                         // getpriority
 842         data8 0                         // setpriority
 843         data8 0                         // statfs
 844         data8 0                         // fstatfs
 845         data8 0                         // gettid               // 1105
 846         data8 0                         // semget
 847         data8 0                         // semop
 848         data8 0                         // semctl
 849         data8 0                         // msgget
 850         data8 0                         // msgsnd               // 1110
 851         data8 0                         // msgrcv
 852         data8 0                         // msgctl
 853         data8 0                         // shmget
 854         data8 0                         // shmat
 855         data8 0                         // shmdt                // 1115
 856         data8 0                         // shmctl
 857         data8 0                         // syslog
 858         data8 0                         // setitimer
 859         data8 0                         // getitimer
 860         data8 0                                                 // 1120
 861         data8 0
 862         data8 0
 863         data8 0                         // vhangup
 864         data8 0                         // lchown
 865         data8 0                         // remap_file_pages     // 1125
 866         data8 0                         // wait4
 867         data8 0                         // sysinfo
 868         data8 0                         // clone
 869         data8 0                         // setdomainname
 870         data8 0                         // newuname             // 1130
 871         data8 0                         // adjtimex
 872         data8 0
 873         data8 0                         // init_module
 874         data8 0                         // delete_module
 875         data8 0                                                 // 1135
 876         data8 0
 877         data8 0                         // quotactl
 878         data8 0                         // bdflush
 879         data8 0                         // sysfs
 880         data8 0                         // personality          // 1140
 881         data8 0                         // afs_syscall
 882         data8 0                         // setfsuid
 883         data8 0                         // setfsgid
 884         data8 0                         // getdents
 885         data8 0                         // flock                // 1145
 886         data8 0                         // readv
 887         data8 0                         // writev
 888         data8 0                         // pread64
 889         data8 0                         // pwrite64
 890         data8 0                         // sysctl               // 1150
 891         data8 0                         // mmap
 892         data8 0                         // munmap
 893         data8 0                         // mlock
 894         data8 0                         // mlockall
 895         data8 0                         // mprotect             // 1155
 896         data8 0                         // mremap
 897         data8 0                         // msync
 898         data8 0                         // munlock
 899         data8 0                         // munlockall
 900         data8 0                         // sched_getparam       // 1160
 901         data8 0                         // sched_setparam
 902         data8 0                         // sched_getscheduler
 903         data8 0                         // sched_setscheduler
 904         data8 0                         // sched_yield
 905         data8 0                         // sched_get_priority_max       // 1165
 906         data8 0                         // sched_get_priority_min
 907         data8 0                         // sched_rr_get_interval
 908         data8 0                         // nanosleep
 909         data8 0                         // nfsservctl
 910         data8 0                         // prctl                // 1170
 911         data8 0                         // getpagesize
 912         data8 0                         // mmap2
 913         data8 0                         // pciconfig_read
 914         data8 0                         // pciconfig_write
 915         data8 0                         // perfmonctl           // 1175
 916         data8 0                         // sigaltstack
 917         data8 0                         // rt_sigaction
 918         data8 0                         // rt_sigpending
 919         data8 fsys_rt_sigprocmask       // rt_sigprocmask
 920         data8 0                         // rt_sigqueueinfo      // 1180
 921         data8 0                         // rt_sigreturn
 922         data8 0                         // rt_sigsuspend
 923         data8 0                         // rt_sigtimedwait
 924         data8 0                         // getcwd
 925         data8 0                         // capget               // 1185
 926         data8 0                         // capset
 927         data8 0                         // sendfile
 928         data8 0
 929         data8 0
 930         data8 0                         // socket               // 1190
 931         data8 0                         // bind
 932         data8 0                         // connect
 933         data8 0                         // listen
 934         data8 0                         // accept
 935         data8 0                         // getsockname          // 1195
 936         data8 0                         // getpeername
 937         data8 0                         // socketpair
 938         data8 0                         // send
 939         data8 0                         // sendto
 940         data8 0                         // recv                 // 1200
 941         data8 0                         // recvfrom
 942         data8 0                         // shutdown
 943         data8 0                         // setsockopt
 944         data8 0                         // getsockopt
 945         data8 0                         // sendmsg              // 1205
 946         data8 0                         // recvmsg
 947         data8 0                         // pivot_root
 948         data8 0                         // mincore
 949         data8 0                         // madvise
 950         data8 0                         // newstat              // 1210
 951         data8 0                         // newlstat
 952         data8 0                         // newfstat
 953         data8 0                         // clone2
 954         data8 0                         // getdents64
 955         data8 0                         // getunwind            // 1215
 956         data8 0                         // readahead
 957         data8 0                         // setxattr
 958         data8 0                         // lsetxattr
 959         data8 0                         // fsetxattr
 960         data8 0                         // getxattr             // 1220
 961         data8 0                         // lgetxattr
 962         data8 0                         // fgetxattr
 963         data8 0                         // listxattr
 964         data8 0                         // llistxattr
 965         data8 0                         // flistxattr           // 1225
 966         data8 0                         // removexattr
 967         data8 0                         // lremovexattr
 968         data8 0                         // fremovexattr
 969         data8 0                         // tkill
 970         data8 0                         // futex                // 1230
 971         data8 0                         // sched_setaffinity
 972         data8 0                         // sched_getaffinity
 973         data8 fsys_set_tid_address      // set_tid_address
 974         data8 0                         // fadvise64_64
 975         data8 0                         // tgkill               // 1235
 976         data8 0                         // exit_group
 977         data8 0                         // lookup_dcookie
 978         data8 0                         // io_setup
 979         data8 0                         // io_destroy
 980         data8 0                         // io_getevents         // 1240
 981         data8 0                         // io_submit
 982         data8 0                         // io_cancel
 983         data8 0                         // epoll_create
 984         data8 0                         // epoll_ctl
 985         data8 0                         // epoll_wait           // 1245
 986         data8 0                         // restart_syscall
 987         data8 0                         // semtimedop
 988         data8 0                         // timer_create
 989         data8 0                         // timer_settime
 990         data8 0                         // timer_gettime        // 1250
 991         data8 0                         // timer_getoverrun
 992         data8 0                         // timer_delete
 993         data8 0                         // clock_settime
 994         data8 fsys_clock_gettime        // clock_gettime
 995         data8 0                         // clock_getres         // 1255
 996         data8 0                         // clock_nanosleep
 997         data8 0                         // fstatfs64
 998         data8 0                         // statfs64
 999         data8 0                         // mbind
1000         data8 0                         // get_mempolicy        // 1260
1001         data8 0                         // set_mempolicy
1002         data8 0                         // mq_open
1003         data8 0                         // mq_unlink
1004         data8 0                         // mq_timedsend
1005         data8 0                         // mq_timedreceive      // 1265
1006         data8 0                         // mq_notify
1007         data8 0                         // mq_getsetattr
1008         data8 0                         // kexec_load
1009         data8 0                         // vserver
1010         data8 0                         // waitid               // 1270
1011         data8 0                         // add_key
1012         data8 0                         // request_key
1013         data8 0                         // keyctl
1014         data8 0                         // ioprio_set
1015         data8 0                         // ioprio_get           // 1275
1016         data8 0                         // move_pages
1017         data8 0                         // inotify_init
1018         data8 0                         // inotify_add_watch
1019         data8 0                         // inotify_rm_watch
1020         data8 0                         // migrate_pages        // 1280
1021         data8 0                         // openat
1022         data8 0                         // mkdirat
1023         data8 0                         // mknodat
1024         data8 0                         // fchownat
1025         data8 0                         // futimesat            // 1285
1026         data8 0                         // newfstatat
1027         data8 0                         // unlinkat
1028         data8 0                         // renameat
1029         data8 0                         // linkat
1030         data8 0                         // symlinkat            // 1290
1031         data8 0                         // readlinkat
1032         data8 0                         // fchmodat
1033         data8 0                         // faccessat
1034         data8 0
1035         data8 0                                                 // 1295
1036         data8 0                         // unshare
1037         data8 0                         // splice
1038         data8 0                         // set_robust_list
1039         data8 0                         // get_robust_list
1040         data8 0                         // sync_file_range      // 1300
1041         data8 0                         // tee
1042         data8 0                         // vmsplice
1043         data8 0
1044         data8 fsys_getcpu               // getcpu               // 1304
1045
1046         // fill in zeros for the remaining entries
1047         .zero:
1048         .space paravirt_fsyscall_table + 8*NR_syscalls - .zero, 0