osfmk/i386/machine_routines_asm.s

   1 /*
   2  * Copyright (c) 2000-2010 Apple Inc. All rights reserved.
   3  *
   4  * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
   5  *
   6  * This file contains Original Code and/or Modifications of Original Code
   7  * as defined in and that are subject to the Apple Public Source License
   8  * Version 2.0 (the 'License'). You may not use this file except in
   9  * compliance with the License. The rights granted to you under the License
  10  * may not be used to create, or enable the creation or redistribution of,
  11  * unlawful or unlicensed copies of an Apple operating system, or to
  12  * circumvent, violate, or enable the circumvention or violation of, any
  13  * terms of an Apple operating system software license agreement.
  14  *
  15  * Please obtain a copy of the License at
  16  * http://www.opensource.apple.com/apsl/ and read it before using this file.
  17  *
  18  * The Original Code and all software distributed under the License are
  19  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  20  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  21  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  22  * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
  23  * Please see the License for the specific language governing rights and
  24  * limitations under the License.
  25  *
  26  * @APPLE_OSREFERENCE_LICENSE_HEADER_END@
  27  */
  28
  29 #include <i386/asm.h>
  30 #include <i386/apic.h>
  31 #include <i386/eflags.h>
  32 #include <i386/rtclock_asm.h>
  33 #include <i386/postcode.h>
  34 #include <i386/proc_reg.h>
  35 #include <assym.s>
  36
  37 /*
  38 **      ml_get_timebase()
  39 **
  40 **      Entry   - %esp contains pointer to 64 bit structure.
  41 **
  42 **      Exit    - 64 bit structure filled in.
  43 **
  44 */
  45 ENTRY(ml_get_timebase)
  46
  47                         movl    S_ARG0, %ecx
  48
  49                         lfence
  50                         rdtsc
  51                         lfence
  52
  53                         movl    %edx, 0(%ecx)
  54                         movl    %eax, 4(%ecx)
  55
  56                         ret
  57
  58 /*
  59  *      Convert between various timer units
  60  *
  61  *              uint64_t tmrCvt(uint64_t time, uint64_t *conversion)
  62  *
  63  *              This code converts 64-bit time units to other units.
  64  *              For example, the TSC is converted to HPET units.
  65  *
  66  *              Time is a 64-bit integer that is some number of ticks.
  67  *              Conversion is 64-bit fixed point number which is composed
  68  *              of a 32 bit integer and a 32 bit fraction.
  69  *
  70  *              The time ticks are multiplied by the conversion factor.  The
  71  *              calculations are done as a 128-bit value but both the high
  72  *              and low words are dropped.  The high word is overflow and the
  73  *              low word is the fraction part of the result.
  74  *
  75  *              We return a 64-bit value.
  76  *
  77  *              Note that we can use this function to multiply 2 conversion factors.
  78  *              We do this in order to calculate the multiplier used to convert
  79  *              directly between any two units.
  80  *
  81  */
  82
  83                         .globl  EXT(tmrCvt)
  84                         .align FALIGN
  85
  86 LEXT(tmrCvt)
  87
  88                         pushl   %ebp                                    // Save a volatile
  89                         movl    %esp,%ebp                               // Get the parameters - 8
  90                         pushl   %ebx                                    // Save a volatile
  91                         pushl   %esi                                    // Save a volatile
  92                         pushl   %edi                                    // Save a volatile
  93
  94 //                      %ebp + 8        - low-order ts
  95 //                      %ebp + 12       - high-order ts
  96 //                      %ebp + 16       - low-order cvt
  97 //                      %ebp + 20       - high-order cvt
  98
  99                         movl    8(%ebp),%eax                    // Get low-order ts
 100                         mull    16(%ebp)                                // Multiply by low-order conversion
 101                         movl    %edx,%edi                               // Need to save only the high order part
 102
 103                         movl    12(%ebp),%eax                   // Get the high-order ts
 104                         mull    16(%ebp)                                // Multiply by low-order conversion
 105                         addl    %eax,%edi                               // Add in the overflow from the low x low calculation
 106                         adcl    $0,%edx                                 // Add in any overflow to high high part
 107                         movl    %edx,%esi                               // Save high high part
 108
 109 //                      We now have the upper 64 bits of the 96 bit multiply of ts and the low half of cvt
 110 //                      in %esi:%edi
 111
 112                         movl    8(%ebp),%eax                    // Get low-order ts
 113                         mull    20(%ebp)                                // Multiply by high-order conversion
 114                         movl    %eax,%ebx                               // Need to save the low order part
 115                         movl    %edx,%ecx                               // Need to save the high order part
 116
 117                         movl    12(%ebp),%eax                   // Get the high-order ts
 118                         mull    20(%ebp)                                // Multiply by high-order conversion
 119
 120 //                      Now have %ecx:%ebx as low part of high low and %edx:%eax as high part of high high
 121 //                      We don't care about the highest word since it is overflow
 122
 123                         addl    %edi,%ebx                               // Add the low words
 124                         adcl    %ecx,%esi                               // Add in the high plus carry from low
 125                         addl    %eax,%esi                               // Add in the rest of the high
 126
 127                         movl    %ebx,%eax                               // Pass back low word
 128                         movl    %esi,%edx                               // and the high word
 129
 130                         popl    %edi                                    // Restore a volatile
 131                         popl    %esi                                    // Restore a volatile
 132                         popl    %ebx                                    // Restore a volatile
 133                         popl    %ebp                                    // Restore a volatile
 134
 135                         ret                                             // Leave...
 136
 137
 138 /* void  _rtc_nanotime_adjust(
 139                 uint64_t         tsc_base_delta,
 140                 rtc_nanotime_t  *dst);
 141 */
 142         .globl  EXT(_rtc_nanotime_adjust)
 143         .align  FALIGN
 144
 145 LEXT(_rtc_nanotime_adjust)
 146         mov     12(%esp),%edx                   /* ptr to rtc_nanotime_info */
 147
 148         movl    RNT_GENERATION(%edx),%ecx       /* get current generation */
 149         movl    $0,RNT_GENERATION(%edx)         /* flag data as being updated */
 150
 151         movl    4(%esp),%eax                    /* get lower 32-bits of delta */
 152         addl    %eax,RNT_TSC_BASE(%edx)
 153         adcl    $0,RNT_TSC_BASE+4(%edx)         /* propagate carry */
 154
 155         incl    %ecx                            /* next generation */
 156         jnz     1f
 157         incl    %ecx                            /* skip 0, which is a flag */
 158 1:      movl    %ecx,RNT_GENERATION(%edx)       /* update generation and make usable */
 159
 160         ret
 161
 162
 163 /* unint64_t _rtc_nanotime_read( rtc_nanotime_t *rntp, int slow );
 164  *
 165  * This is the same as the commpage nanotime routine, except that it uses the
 166  * kernel internal "rtc_nanotime_info" data instead of the commpage data.  The two copies
 167  * of data (one in the kernel and one in user space) are kept in sync by rtc_clock_napped().
 168  *
 169  * Warning!  There is another copy of this code in osfmk/i386/locore.s.  The
 170  * two versions must be kept in sync with each other!
 171  *
 172  * There are actually two versions of the algorithm, one each for "slow" and "fast"
 173  * processors.  The more common "fast" algorithm is:
 174  *
 175  *      nanoseconds = (((rdtsc - rnt_tsc_base) * rnt_tsc_scale) / 2**32) - rnt_ns_base;
 176  *
 177  * Of course, the divide by 2**32 is a nop.  rnt_tsc_scale is a constant computed during initialization:
 178  *
 179  *      rnt_tsc_scale = (10e9 * 2**32) / tscFreq;
 180  *
 181  * The "slow" algorithm uses long division:
 182  *
 183  *      nanoseconds = (((rdtsc - rnt_tsc_base) * 10e9) / tscFreq) - rnt_ns_base;
 184  *
 185  * Since this routine is not synchronized and can be called in any context,
 186  * we use a generation count to guard against seeing partially updated data.  In addition,
 187  * the _rtc_nanotime_store() routine -- just above -- zeroes the generation before
 188  * updating the data, and stores the nonzero generation only after all other data has been
 189  * stored.  Because IA32 guarantees that stores by one processor must be seen in order
 190  * by another, we can avoid using a lock.  We spin while the generation is zero.
 191  *
 192  * In accordance with the ABI, we return the 64-bit nanotime in %edx:%eax.
 193  */
 194
 195                 .globl  EXT(_rtc_nanotime_read)
 196                 .align  FALIGN
 197 LEXT(_rtc_nanotime_read)
 198                 pushl           %ebp
 199                 movl            %esp,%ebp
 200                 pushl           %esi
 201                 pushl           %edi
 202                 pushl           %ebx
 203                 movl            8(%ebp),%edi                            /* get ptr to rtc_nanotime_info */
 204                 movl            12(%ebp),%eax                           /* get "slow" flag */
 205                 testl           %eax,%eax
 206                 jnz             Lslow
 207
 208                 /* Processor whose TSC frequency is faster than SLOW_TSC_THRESHOLD */
 209                 PAL_RTC_NANOTIME_READ_FAST()
 210
 211                 popl            %ebx
 212                 popl            %edi
 213                 popl            %esi
 214                 popl            %ebp
 215                 ret
 216
 217                 /* Processor whose TSC frequency is slower than or equal to SLOW_TSC_THRESHOLD */
 218 Lslow:
 219                 movl            RNT_GENERATION(%edi),%esi               /* get generation (0 if being changed) */
 220                 testl           %esi,%esi                               /* if being changed, loop until stable */
 221                 jz              Lslow
 222                 pushl           %esi                                    /* save generation */
 223                 pushl           RNT_SHIFT(%edi)                         /* save low 32 bits of tscFreq */
 224
 225                 lfence
 226                 rdtsc                                                   /* get TSC in %edx:%eax */
 227                 lfence
 228                 subl            RNT_TSC_BASE(%edi),%eax
 229                 sbbl            RNT_TSC_BASE+4(%edi),%edx
 230
 231                 /*
 232                 * Do the math to convert tsc ticks to nanoseconds.  We first
 233                 * do long multiply of 1 billion times the tsc.  Then we do
 234                 * long division by the tsc frequency
 235                 */
 236                 mov             $1000000000, %ecx                       /* number of nanoseconds in a second */
 237                 mov             %edx, %ebx
 238                 mul             %ecx
 239                 mov             %edx, %edi
 240                 mov             %eax, %esi
 241                 mov             %ebx, %eax
 242                 mul             %ecx
 243                 add             %edi, %eax
 244                 adc             $0, %edx                                /* result in edx:eax:esi */
 245                 mov             %eax, %edi
 246                 popl            %ecx                                    /* get low 32 tscFreq */
 247                 xor             %eax, %eax
 248                 xchg            %edx, %eax
 249                 div             %ecx
 250                 xor             %eax, %eax
 251                 mov             %edi, %eax
 252                 div             %ecx
 253                 mov             %eax, %ebx
 254                 mov             %esi, %eax
 255                 div             %ecx
 256                 mov             %ebx, %edx                              /* result in edx:eax */
 257
 258                 movl            8(%ebp),%edi                            /* recover ptr to rtc_nanotime_info */
 259                 popl            %esi                                    /* recover generation */
 260
 261                 addl            RNT_NS_BASE(%edi),%eax
 262                 adcl            RNT_NS_BASE+4(%edi),%edx
 263
 264                 cmpl            RNT_GENERATION(%edi),%esi               /* have the parameters changed? */
 265                 jne             Lslow                                   /* yes, loop until stable */
 266
 267                 pop             %ebx
 268                 pop             %edi
 269                 pop             %esi
 270                 pop             %ebp
 271                 ret                                                     /* result in edx:eax */
 272
 273
 274
 275 /*
 276  * Timing routines.
 277  */
 278 Entry(timer_update)
 279         movl    4(%esp),%ecx
 280         movl    8(%esp),%eax
 281         movl    12(%esp),%edx
 282         movl    %eax,TIMER_HIGHCHK(%ecx)
 283         movl    %edx,TIMER_LOW(%ecx)
 284         movl    %eax,TIMER_HIGH(%ecx)
 285         ret
 286
 287 Entry(timer_grab)
 288         movl    4(%esp),%ecx
 289 0:      movl    TIMER_HIGH(%ecx),%edx
 290         movl    TIMER_LOW(%ecx),%eax
 291         cmpl    TIMER_HIGHCHK(%ecx),%edx
 292         jne     0b
 293         ret
 294
 295
 296 Entry(call_continuation)
 297         movl    S_ARG0,%eax                     /* get continuation */
 298         movl    S_ARG1,%edx                     /* continuation param */
 299         movl    S_ARG2,%ecx                     /* wait result */
 300         movl    %gs:CPU_KERNEL_STACK,%esp       /* pop the stack */
 301         xorl    %ebp,%ebp                       /* zero frame pointer */
 302         subl    $8,%esp                         /* align the stack */
 303         pushl   %ecx
 304         pushl   %edx
 305         call    *%eax                           /* call continuation */
 306         addl    $16,%esp
 307         movl    %gs:CPU_ACTIVE_THREAD,%eax
 308         pushl   %eax
 309         call    EXT(thread_terminate)
 310
 311
 312 Entry(ml_early_random)
 313         xor     %eax, %eax
 314         ret