diff options
Diffstat (limited to 'arch/ia64/kernel/fsys.S')
| -rw-r--r-- | arch/ia64/kernel/fsys.S | 179 |
1 files changed, 88 insertions, 91 deletions
diff --git a/arch/ia64/kernel/fsys.S b/arch/ia64/kernel/fsys.S index 3f926c2..4484197 100644 --- a/arch/ia64/kernel/fsys.S +++ b/arch/ia64/kernel/fsys.S @@ -147,12 +147,11 @@ ENTRY(fsys_set_tid_address) FSYS_RETURN END(fsys_set_tid_address) -/* - * Ensure that the time interpolator structure is compatible with the asm code - */ -#if IA64_TIME_INTERPOLATOR_SOURCE_OFFSET !=0 || IA64_TIME_INTERPOLATOR_SHIFT_OFFSET != 2 \ - || IA64_TIME_INTERPOLATOR_JITTER_OFFSET != 3 || IA64_TIME_INTERPOLATOR_NSEC_OFFSET != 4 -#error fsys_gettimeofday incompatible with changes to struct time_interpolator +#if IA64_GTOD_LOCK_OFFSET !=0 +#error fsys_gettimeofday incompatible with changes to struct fsyscall_gtod_data_t +#endif +#if IA64_ITC_JITTER_OFFSET !=0 +#error fsys_gettimeofday incompatible with changes to struct itc_jitter_data_t #endif #define CLOCK_REALTIME 0 #define CLOCK_MONOTONIC 1 @@ -179,126 +178,124 @@ ENTRY(fsys_gettimeofday) // r11 = preserved: saved ar.pfs // r12 = preserved: memory stack // r13 = preserved: thread pointer - // r14 = address of mask / mask + // r14 = address of mask / mask value // r15 = preserved: system call number // r16 = preserved: current task pointer - // r17 = wall to monotonic use - // r18 = time_interpolator->offset - // r19 = address of wall_to_monotonic - // r20 = pointer to struct time_interpolator / pointer to time_interpolator->address - // r21 = shift factor - // r22 = address of time interpolator->last_counter - // r23 = address of time_interpolator->last_cycle - // r24 = adress of time_interpolator->offset - // r25 = last_cycle value - // r26 = last_counter value - // r27 = pointer to xtime + // r17 = (not used) + // r18 = (not used) + // r19 = address of itc_lastcycle + // r20 = struct fsyscall_gtod_data (= address of gtod_lock.sequence) + // r21 = address of mmio_ptr + // r22 = address of wall_time or monotonic_time + // r23 = address of shift / value + // r24 = address mult factor / cycle_last value + // r25 = itc_lastcycle value + // r26 = address clocksource cycle_last + // r27 = (not used) // r28 = sequence number at the beginning of critcal section - // r29 = address of seqlock + // r29 = address of itc_jitter // r30 = time processing flags / memory address // r31 = pointer to result // Predicates // p6,p7 short term use // p8 = timesource ar.itc // p9 = timesource mmio64 - // p10 = timesource mmio32 + // p10 = timesource mmio32 - not used // p11 = timesource not to be handled by asm code - // p12 = memory time source ( = p9 | p10) - // p13 = do cmpxchg with time_interpolator_last_cycle + // p12 = memory time source ( = p9 | p10) - not used + // p13 = do cmpxchg with itc_lastcycle // p14 = Divide by 1000 // p15 = Add monotonic // - // Note that instructions are optimized for McKinley. McKinley can process two - // bundles simultaneously and therefore we continuously try to feed the CPU - // two bundles and then a stop. - tnat.nz p6,p0 = r31 // branch deferred since it does not fit into bundle structure + // Note that instructions are optimized for McKinley. McKinley can + // process two bundles simultaneously and therefore we continuously + // try to feed the CPU two bundles and then a stop. + // + // Additional note that code has changed a lot. Optimization is TBD. + // Comments begin with "?" are maybe outdated. + tnat.nz p6,p0 = r31 // ? branch deferred to fit later bundle mov pr = r30,0xc000 // Set predicates according to function add r2 = TI_FLAGS+IA64_TASK_SIZE,r16 - movl r20 = time_interpolator + movl r20 = fsyscall_gtod_data // load fsyscall gettimeofday data address ;; - ld8 r20 = [r20] // get pointer to time_interpolator structure - movl r29 = xtime_lock + movl r29 = itc_jitter_data // itc_jitter + add r22 = IA64_GTOD_WALL_TIME_OFFSET,r20 // wall_time ld4 r2 = [r2] // process work pending flags - movl r27 = xtime - ;; // only one bundle here - ld8 r21 = [r20] // first quad with control information + ;; +(p15) add r22 = IA64_GTOD_MONO_TIME_OFFSET,r20 // monotonic_time + add r21 = IA64_CLKSRC_MMIO_OFFSET,r20 + add r19 = IA64_ITC_LASTCYCLE_OFFSET,r29 and r2 = TIF_ALLWORK_MASK,r2 -(p6) br.cond.spnt.few .fail_einval // deferred branch +(p6) br.cond.spnt.few .fail_einval // ? deferred branch ;; - add r10 = IA64_TIME_INTERPOLATOR_ADDRESS_OFFSET,r20 - extr r3 = r21,32,32 // time_interpolator->nsec_per_cyc - extr r8 = r21,0,16 // time_interpolator->source + add r26 = IA64_CLKSRC_CYCLE_LAST_OFFSET,r20 // clksrc_cycle_last cmp.ne p6, p0 = 0, r2 // Fallback if work is scheduled (p6) br.cond.spnt.many fsys_fallback_syscall ;; - cmp.eq p8,p12 = 0,r8 // Check for cpu timer - cmp.eq p9,p0 = 1,r8 // MMIO64 ? - extr r2 = r21,24,8 // time_interpolator->jitter - cmp.eq p10,p0 = 2,r8 // MMIO32 ? - cmp.ltu p11,p0 = 2,r8 // function or other clock -(p11) br.cond.spnt.many fsys_fallback_syscall + // Begin critical section +.time_redo: + ld4.acq r28 = [r20] // gtod_lock.sequence, Must take first + ;; + and r28 = ~1,r28 // And make sequence even to force retry if odd ;; - setf.sig f7 = r3 // Setup for scaling of counter -(p15) movl r19 = wall_to_monotonic -(p12) ld8 r30 = [r10] - cmp.ne p13,p0 = r2,r0 // need jitter compensation? - extr r21 = r21,16,8 // shift factor + ld8 r30 = [r21] // clocksource->mmio_ptr + add r24 = IA64_CLKSRC_MULT_OFFSET,r20 + ld4 r2 = [r29] // itc_jitter value + add r23 = IA64_CLKSRC_SHIFT_OFFSET,r20 + add r14 = IA64_CLKSRC_MASK_OFFSET,r20 ;; -.time_redo: - .pred.rel.mutex p8,p9,p10 - ld4.acq r28 = [r29] // xtime_lock.sequence. Must come first for locking purposes + ld4 r3 = [r24] // clocksource mult value + ld8 r14 = [r14] // clocksource mask value + cmp.eq p8,p9 = 0,r30 // use cpu timer if no mmio_ptr ;; - and r28 = ~1,r28 // Make sequence even to force retry if odd + setf.sig f7 = r3 // Setup for mult scaling of counter +(p8) cmp.ne p13,p0 = r2,r0 // need itc_jitter compensation, set p13 + ld4 r23 = [r23] // clocksource shift value + ld8 r24 = [r26] // get clksrc_cycle_last value +(p9) cmp.eq p13,p0 = 0,r30 // if mmio_ptr, clear p13 jitter control ;; + .pred.rel.mutex p8,p9 (p8) mov r2 = ar.itc // CPU_TIMER. 36 clocks latency!!! - add r22 = IA64_TIME_INTERPOLATOR_LAST_COUNTER_OFFSET,r20 -(p9) ld8 r2 = [r30] // readq(ti->address). Could also have latency issues.. -(p10) ld4 r2 = [r30] // readw(ti->address) -(p13) add r23 = IA64_TIME_INTERPOLATOR_LAST_CYCLE_OFFSET,r20 - ;; // could be removed by moving the last add upward - ld8 r26 = [r22] // time_interpolator->last_counter -(p13) ld8 r25 = [r23] // time interpolator->last_cycle - add r24 = IA64_TIME_INTERPOLATOR_OFFSET_OFFSET,r20 -(p15) ld8 r17 = [r19],IA64_TIMESPEC_TV_NSEC_OFFSET - ld8 r9 = [r27],IA64_TIMESPEC_TV_NSEC_OFFSET - add r14 = IA64_TIME_INTERPOLATOR_MASK_OFFSET, r20 - ;; - ld8 r18 = [r24] // time_interpolator->offset - ld8 r8 = [r27],-IA64_TIMESPEC_TV_NSEC_OFFSET // xtime.tv_nsec -(p13) sub r3 = r25,r2 // Diff needed before comparison (thanks davidm) - ;; - ld8 r14 = [r14] // time_interpolator->mask -(p13) cmp.gt.unc p6,p7 = r3,r0 // check if it is less than last. p6,p7 cleared - sub r10 = r2,r26 // current_counter - last_counter - ;; -(p6) sub r10 = r25,r26 // time we got was less than last_cycle +(p9) ld8 r2 = [r30] // MMIO_TIMER. Could also have latency issues.. +(p13) ld8 r25 = [r19] // get itc_lastcycle value + ;; // ? could be removed by moving the last add upward + ld8 r9 = [r22],IA64_TIMESPEC_TV_NSEC_OFFSET // tv_sec + ;; + ld8 r8 = [r22],-IA64_TIMESPEC_TV_NSEC_OFFSET // tv_nsec +(p13) sub r3 = r25,r2 // Diff needed before comparison (thanks davidm) + ;; +(p13) cmp.gt.unc p6,p7 = r3,r0 // check if it is less than last. p6,p7 cleared + sub r10 = r2,r24 // current_cycle - last_cycle + ;; +(p6) sub r10 = r25,r24 // time we got was less than last_cycle (p7) mov ar.ccv = r25 // more than last_cycle. Prep for cmpxchg ;; +(p7) cmpxchg8.rel r3 = [r19],r2,ar.ccv + ;; +(p7) cmp.ne p7,p0 = r25,r3 // if cmpxchg not successful + ;; +(p7) sub r10 = r3,r24 // then use new last_cycle instead + ;; and r10 = r10,r14 // Apply mask ;; setf.sig f8 = r10 nop.i 123 ;; -(p7) cmpxchg8.rel r3 = [r23],r2,ar.ccv -EX(.fail_efault, probe.w.fault r31, 3) // This takes 5 cycles and we have spare time + // fault check takes 5 cycles and we have spare time +EX(.fail_efault, probe.w.fault r31, 3) xmpy.l f8 = f8,f7 // nsec_per_cyc*(counter-last_counter) -(p15) add r9 = r9,r17 // Add wall to monotonic.secs to result secs ;; -(p15) ld8 r17 = [r19],-IA64_TIMESPEC_TV_NSEC_OFFSET -(p7) cmp.ne p7,p0 = r25,r3 // if cmpxchg not successful redo - // simulate tbit.nz.or p7,p0 = r28,0 + // ? simulate tbit.nz.or p7,p0 = r28,0 getf.sig r2 = f8 mf - add r8 = r8,r18 // Add time interpolator offset ;; - ld4 r10 = [r29] // xtime_lock.sequence -(p15) add r8 = r8, r17 // Add monotonic.nsecs to nsecs - shr.u r2 = r2,r21 - ;; // overloaded 3 bundles! - // End critical section. + ld4 r10 = [r20] // gtod_lock.sequence + shr.u r2 = r2,r23 // shift by factor + ;; // ? overloaded 3 bundles! add r8 = r8,r2 // Add xtime.nsecs - cmp4.ne.or p7,p0 = r28,r10 -(p7) br.cond.dpnt.few .time_redo // sequence number changed ? + cmp4.ne p7,p0 = r28,r10 +(p7) br.cond.dpnt.few .time_redo // sequence number changed, redo + // End critical section. // Now r8=tv->tv_nsec and r9=tv->tv_sec mov r10 = r0 movl r2 = 1000000000 @@ -308,19 +305,19 @@ EX(.fail_efault, probe.w.fault r31, 3) // This takes 5 cycles and we have spare .time_normalize: mov r21 = r8 cmp.ge p6,p0 = r8,r2 -(p14) shr.u r20 = r8, 3 // We can repeat this if necessary just wasting some time +(p14) shr.u r20 = r8, 3 // We can repeat this if necessary just wasting time ;; (p14) setf.sig f8 = r20 (p6) sub r8 = r8,r2 -(p6) add r9 = 1,r9 // two nops before the branch. -(p14) setf.sig f7 = r3 // Chances for repeats are 1 in 10000 for gettod +(p6) add r9 = 1,r9 // two nops before the branch. +(p14) setf.sig f7 = r3 // Chances for repeats are 1 in 10000 for gettod (p6) br.cond.dpnt.few .time_normalize ;; // Divided by 8 though shift. Now divide by 125 // The compiler was able to do that with a multiply // and a shift and we do the same -EX(.fail_efault, probe.w.fault r23, 3) // This also costs 5 cycles -(p14) xmpy.hu f8 = f8, f7 // xmpy has 5 cycles latency so use it... +EX(.fail_efault, probe.w.fault r23, 3) // This also costs 5 cycles +(p14) xmpy.hu f8 = f8, f7 // xmpy has 5 cycles latency so use it ;; mov r8 = r0 (p14) getf.sig r2 = f8 |