1 // Copyright 2013 the V8 project authors. All rights reserved.
2 // Use of this source code is governed by a BSD-style license that can be
3 // found in the LICENSE file.
4 
5 #include "src/base/cpu.h"
6 
7 #if V8_LIBC_MSVCRT
8 #include <intrin.h>  // __cpuid()
9 #endif
10 #if V8_OS_LINUX
11 #include <linux/auxvec.h>  // AT_HWCAP
12 #endif
13 #if V8_GLIBC_PREREQ(2, 16)
14 #include <sys/auxv.h>  // getauxval()
15 #endif
16 #if V8_OS_QNX
17 #include <sys/syspage.h>  // cpuinfo
18 #endif
19 #if V8_OS_LINUX && V8_HOST_ARCH_PPC
20 #include <elf.h>
21 #endif
22 #if V8_OS_AIX
23 #include <sys/systemcfg.h>  // _system_configuration
24 #ifndef POWER_8
25 #define POWER_8 0x10000
26 #endif
27 #endif
28 #if V8_OS_POSIX
29 #include <unistd.h>  // sysconf()
30 #endif
31 
32 #include <ctype.h>
33 #include <limits.h>
34 #include <stdio.h>
35 #include <stdlib.h>
36 #include <string.h>
37 #include <algorithm>
38 
39 #include "src/base/logging.h"
40 #if V8_OS_WIN
41 #include "src/base/win32-headers.h"  // NOLINT
42 #endif
43 
44 namespace v8 {
45 namespace base {
46 
47 #if defined(__pnacl__)
48 // Portable host shouldn't do feature detection.
49 #elif V8_HOST_ARCH_IA32 || V8_HOST_ARCH_X64
50 
51 // Define __cpuid() for non-MSVC libraries.
52 #if !V8_LIBC_MSVCRT
53 
54 static V8_INLINE void __cpuid(int cpu_info[4], int info_type) {
55 // Clear ecx to align with __cpuid() of MSVC:
56 // https://msdn.microsoft.com/en-us/library/hskdteyh.aspx
57 #if defined(__i386__) && defined(__pic__)
58   // Make sure to preserve ebx, which contains the pointer
59   // to the GOT in case we're generating PIC.
60   __asm__ volatile(
61       "mov %%ebx, %%edi\n\t"
62       "cpuid\n\t"
63       "xchg %%edi, %%ebx\n\t"
64       : "=a"(cpu_info[0]), "=D"(cpu_info[1]), "=c"(cpu_info[2]),
65         "=d"(cpu_info[3])
66       : "a"(info_type), "c"(0));
67 #else
68   __asm__ volatile("cpuid \n\t"
69                    : "=a"(cpu_info[0]), "=b"(cpu_info[1]), "=c"(cpu_info[2]),
70                      "=d"(cpu_info[3])
71                    : "a"(info_type), "c"(0));
72 #endif  // defined(__i386__) && defined(__pic__)
73 }
74 
75 #endif  // !V8_LIBC_MSVCRT
76 
77 #elif V8_HOST_ARCH_ARM || V8_HOST_ARCH_ARM64 \
78     || V8_HOST_ARCH_MIPS || V8_HOST_ARCH_MIPS64
79 
80 #if V8_OS_LINUX
81 
82 #if V8_HOST_ARCH_ARM
83 
84 // See <uapi/asm/hwcap.h> kernel header.
85 /*
86  * HWCAP flags - for elf_hwcap (in kernel) and AT_HWCAP
87  */
88 #define HWCAP_SWP (1 << 0)
89 #define HWCAP_HALF  (1 << 1)
90 #define HWCAP_THUMB (1 << 2)
91 #define HWCAP_26BIT (1 << 3)  /* Play it safe */
92 #define HWCAP_FAST_MULT (1 << 4)
93 #define HWCAP_FPA (1 << 5)
94 #define HWCAP_VFP (1 << 6)
95 #define HWCAP_EDSP  (1 << 7)
96 #define HWCAP_JAVA  (1 << 8)
97 #define HWCAP_IWMMXT  (1 << 9)
98 #define HWCAP_CRUNCH  (1 << 10)
99 #define HWCAP_THUMBEE (1 << 11)
100 #define HWCAP_NEON  (1 << 12)
101 #define HWCAP_VFPv3 (1 << 13)
102 #define HWCAP_VFPv3D16  (1 << 14) /* also set for VFPv4-D16 */
103 #define HWCAP_TLS (1 << 15)
104 #define HWCAP_VFPv4 (1 << 16)
105 #define HWCAP_IDIVA (1 << 17)
106 #define HWCAP_IDIVT (1 << 18)
107 #define HWCAP_VFPD32  (1 << 19) /* set if VFP has 32 regs (not 16) */
108 #define HWCAP_IDIV  (HWCAP_IDIVA | HWCAP_IDIVT)
109 #define HWCAP_LPAE  (1 << 20)
110 
111 static uint32_t ReadELFHWCaps() {
112   uint32_t result = 0;
113 #if V8_GLIBC_PREREQ(2, 16)
114   result = static_cast<uint32_t>(getauxval(AT_HWCAP));
115 #else
116   // Read the ELF HWCAP flags by parsing /proc/self/auxv.
117   FILE* fp = fopen("/proc/self/auxv", "r");
118   if (fp != NULL) {
119     struct { uint32_t tag; uint32_t value; } entry;
120     for (;;) {
121       size_t n = fread(&entry, sizeof(entry), 1, fp);
122       if (n == 0 || (entry.tag == 0 && entry.value == 0)) {
123         break;
124       }
125       if (entry.tag == AT_HWCAP) {
126         result = entry.value;
127         break;
128       }
129     }
130     fclose(fp);
131   }
132 #endif
133   return result;
134 }
135 
136 #endif  // V8_HOST_ARCH_ARM
137 
138 #if V8_HOST_ARCH_MIPS
139 int __detect_fp64_mode(void) {
140   double result = 0;
141   // Bit representation of (double)1 is 0x3FF0000000000000.
142   __asm__ volatile(
143       ".set push\n\t"
144       ".set noreorder\n\t"
145       ".set oddspreg\n\t"
146       "lui $t0, 0x3FF0\n\t"
147       "ldc1 $f0, %0\n\t"
148       "mtc1 $t0, $f1\n\t"
149       "sdc1 $f0, %0\n\t"
150       ".set pop\n\t"
151       : "+m"(result)
152       :
153       : "t0", "$f0", "$f1", "memory");
154 
155   return !(result == 1);
156 }
157 
158 
159 int __detect_mips_arch_revision(void) {
160   // TODO(dusmil): Do the specific syscall as soon as it is implemented in mips
161   // kernel.
162   uint32_t result = 0;
163   __asm__ volatile(
164       "move $v0, $zero\n\t"
165       // Encoding for "addi $v0, $v0, 1" on non-r6,
166       // which is encoding for "bovc $v0, %v0, 1" on r6.
167       // Use machine code directly to avoid compilation errors with different
168       // toolchains and maintain compatibility.
169       ".word 0x20420001\n\t"
170       "sw $v0, %0\n\t"
171       : "=m"(result)
172       :
173       : "v0", "memory");
174   // Result is 0 on r6 architectures, 1 on other architecture revisions.
175   // Fall-back to the least common denominator which is mips32 revision 1.
176   return result ? 1 : 6;
177 }
178 #endif
179 
180 // Extract the information exposed by the kernel via /proc/cpuinfo.
181 class CPUInfo final {
182  public:
183   CPUInfo() : datalen_(0) {
184     // Get the size of the cpuinfo file by reading it until the end. This is
185     // required because files under /proc do not always return a valid size
186     // when using fseek(0, SEEK_END) + ftell(). Nor can the be mmap()-ed.
187     static const char PATHNAME[] = "/proc/cpuinfo";
188     FILE* fp = fopen(PATHNAME, "r");
189     if (fp != NULL) {
190       for (;;) {
191         char buffer[256];
192         size_t n = fread(buffer, 1, sizeof(buffer), fp);
193         if (n == 0) {
194           break;
195         }
196         datalen_ += n;
197       }
198       fclose(fp);
199     }
200 
201     // Read the contents of the cpuinfo file.
202     data_ = new char[datalen_ + 1];
203     fp = fopen(PATHNAME, "r");
204     if (fp != NULL) {
205       for (size_t offset = 0; offset < datalen_; ) {
206         size_t n = fread(data_ + offset, 1, datalen_ - offset, fp);
207         if (n == 0) {
208           break;
209         }
210         offset += n;
211       }
212       fclose(fp);
213     }
214 
215     // Zero-terminate the data.
216     data_[datalen_] = '\0';
217   }
218 
219   ~CPUInfo() {
220     delete[] data_;
221   }
222 
223   // Extract the content of a the first occurence of a given field in
224   // the content of the cpuinfo file and return it as a heap-allocated
225   // string that must be freed by the caller using delete[].
226   // Return NULL if not found.
227   char* ExtractField(const char* field) const {
228     DCHECK(field != NULL);
229 
230     // Look for first field occurence, and ensure it starts the line.
231     size_t fieldlen = strlen(field);
232     char* p = data_;
233     for (;;) {
234       p = strstr(p, field);
235       if (p == NULL) {
236         return NULL;
237       }
238       if (p == data_ || p[-1] == '\n') {
239         break;
240       }
241       p += fieldlen;
242     }
243 
244     // Skip to the first colon followed by a space.
245     p = strchr(p + fieldlen, ':');
246     if (p == NULL || !isspace(p[1])) {
247       return NULL;
248     }
249     p += 2;
250 
251     // Find the end of the line.
252     char* q = strchr(p, '\n');
253     if (q == NULL) {
254       q = data_ + datalen_;
255     }
256 
257     // Copy the line into a heap-allocated buffer.
258     size_t len = q - p;
259     char* result = new char[len + 1];
260     if (result != NULL) {
261       memcpy(result, p, len);
262       result[len] = '\0';
263     }
264     return result;
265   }
266 
267  private:
268   char* data_;
269   size_t datalen_;
270 };
271 
272 #if V8_HOST_ARCH_ARM || V8_HOST_ARCH_MIPS || V8_HOST_ARCH_MIPS64
273 
274 // Checks that a space-separated list of items contains one given 'item'.
275 static bool HasListItem(const char* list, const char* item) {
276   ssize_t item_len = strlen(item);
277   const char* p = list;
278   if (p != NULL) {
279     while (*p != '\0') {
280       // Skip whitespace.
281       while (isspace(*p)) ++p;
282 
283       // Find end of current list item.
284       const char* q = p;
285       while (*q != '\0' && !isspace(*q)) ++q;
286 
287       if (item_len == q - p && memcmp(p, item, item_len) == 0) {
288         return true;
289       }
290 
291       // Skip to next item.
292       p = q;
293     }
294   }
295   return false;
296 }
297 
298 #endif  // V8_HOST_ARCH_ARM || V8_HOST_ARCH_MIPS || V8_HOST_ARCH_MIPS64
299 
300 #endif  // V8_OS_LINUX
301 
302 #endif  // V8_HOST_ARCH_IA32 || V8_HOST_ARCH_X64
303 
CPU()304 CPU::CPU()
305     : stepping_(0),
306       model_(0),
307       ext_model_(0),
308       family_(0),
309       ext_family_(0),
310       type_(0),
311       implementer_(0),
312       architecture_(0),
313       variant_(-1),
314       part_(0),
315       has_fpu_(false),
316       has_cmov_(false),
317       has_sahf_(false),
318       has_mmx_(false),
319       has_sse_(false),
320       has_sse2_(false),
321       has_sse3_(false),
322       has_ssse3_(false),
323       has_sse41_(false),
324       has_sse42_(false),
325       is_atom_(false),
326       has_osxsave_(false),
327       has_avx_(false),
328       has_fma3_(false),
329       has_bmi1_(false),
330       has_bmi2_(false),
331       has_lzcnt_(false),
332       has_popcnt_(false),
333       has_idiva_(false),
334       has_neon_(false),
335       has_thumb2_(false),
336       has_vfp_(false),
337       has_vfp3_(false),
338       has_vfp3_d32_(false),
339       is_fp64_mode_(false) {
340   memcpy(vendor_, "Unknown", 8);
341 #if V8_OS_NACL
342 // Portable host shouldn't do feature detection.
343 // TODO(jfb): Remove the hardcoded ARM simulator flags in the build, and
344 // hardcode them here instead.
345 #elif V8_HOST_ARCH_IA32 || V8_HOST_ARCH_X64
346   int cpu_info[4];
347 
348   // __cpuid with an InfoType argument of 0 returns the number of
349   // valid Ids in CPUInfo[0] and the CPU identification string in
350   // the other three array elements. The CPU identification string is
351   // not in linear order. The code below arranges the information
352   // in a human readable form. The human readable order is CPUInfo[1] |
353   // CPUInfo[3] | CPUInfo[2]. CPUInfo[2] and CPUInfo[3] are swapped
354   // before using memcpy to copy these three array elements to cpu_string.
355   __cpuid(cpu_info, 0);
356   unsigned num_ids = cpu_info[0];
357   std::swap(cpu_info[2], cpu_info[3]);
358   memcpy(vendor_, cpu_info + 1, 12);
359   vendor_[12] = '\0';
360 
361   // Interpret CPU feature information.
362   if (num_ids > 0) {
363     __cpuid(cpu_info, 1);
364     stepping_ = cpu_info[0] & 0xf;
365     model_ = ((cpu_info[0] >> 4) & 0xf) + ((cpu_info[0] >> 12) & 0xf0);
366     family_ = (cpu_info[0] >> 8) & 0xf;
367     type_ = (cpu_info[0] >> 12) & 0x3;
368     ext_model_ = (cpu_info[0] >> 16) & 0xf;
369     ext_family_ = (cpu_info[0] >> 20) & 0xff;
370     has_fpu_ = (cpu_info[3] & 0x00000001) != 0;
371     has_cmov_ = (cpu_info[3] & 0x00008000) != 0;
372     has_mmx_ = (cpu_info[3] & 0x00800000) != 0;
373     has_sse_ = (cpu_info[3] & 0x02000000) != 0;
374     has_sse2_ = (cpu_info[3] & 0x04000000) != 0;
375     has_sse3_ = (cpu_info[2] & 0x00000001) != 0;
376     has_ssse3_ = (cpu_info[2] & 0x00000200) != 0;
377     has_sse41_ = (cpu_info[2] & 0x00080000) != 0;
378     has_sse42_ = (cpu_info[2] & 0x00100000) != 0;
379     has_popcnt_ = (cpu_info[2] & 0x00800000) != 0;
380     has_osxsave_ = (cpu_info[2] & 0x08000000) != 0;
381     has_avx_ = (cpu_info[2] & 0x10000000) != 0;
382     has_fma3_ = (cpu_info[2] & 0x00001000) != 0;
383 
384     if (family_ == 0x6) {
385       switch (model_) {
386         case 0x1c:  // SLT
387         case 0x26:
388         case 0x36:
389         case 0x27:
390         case 0x35:
391         case 0x37:  // SLM
392         case 0x4a:
393         case 0x4d:
394         case 0x4c:  // AMT
395         case 0x6e:
396           is_atom_ = true;
397       }
398     }
399   }
400 
401   // There are separate feature flags for VEX-encoded GPR instructions.
402   if (num_ids >= 7) {
403     __cpuid(cpu_info, 7);
404     has_bmi1_ = (cpu_info[1] & 0x00000008) != 0;
405     has_bmi2_ = (cpu_info[1] & 0x00000100) != 0;
406   }
407 
408   // Query extended IDs.
409   __cpuid(cpu_info, 0x80000000);
410   unsigned num_ext_ids = cpu_info[0];
411 
412   // Interpret extended CPU feature information.
413   if (num_ext_ids > 0x80000000) {
414     __cpuid(cpu_info, 0x80000001);
415     has_lzcnt_ = (cpu_info[2] & 0x00000020) != 0;
416     // SAHF must be probed in long mode.
417     has_sahf_ = (cpu_info[2] & 0x00000001) != 0;
418   }
419 
420 #elif V8_HOST_ARCH_ARM
421 
422 #if V8_OS_LINUX
423 
424   CPUInfo cpu_info;
425 
426   // Extract implementor from the "CPU implementer" field.
427   char* implementer = cpu_info.ExtractField("CPU implementer");
428   if (implementer != NULL) {
429     char* end;
430     implementer_ = strtol(implementer, &end, 0);
431     if (end == implementer) {
432       implementer_ = 0;
433     }
434     delete[] implementer;
435   }
436 
437   char* variant = cpu_info.ExtractField("CPU variant");
438   if (variant != NULL) {
439     char* end;
440     variant_ = strtol(variant, &end, 0);
441     if (end == variant) {
442       variant_ = -1;
443     }
444     delete[] variant;
445   }
446 
447   // Extract part number from the "CPU part" field.
448   char* part = cpu_info.ExtractField("CPU part");
449   if (part != NULL) {
450     char* end;
451     part_ = strtol(part, &end, 0);
452     if (end == part) {
453       part_ = 0;
454     }
455     delete[] part;
456   }
457 
458   // Extract architecture from the "CPU Architecture" field.
459   // The list is well-known, unlike the the output of
460   // the 'Processor' field which can vary greatly.
461   // See the definition of the 'proc_arch' array in
462   // $KERNEL/arch/arm/kernel/setup.c and the 'c_show' function in
463   // same file.
464   char* architecture = cpu_info.ExtractField("CPU architecture");
465   if (architecture != NULL) {
466     char* end;
467     architecture_ = strtol(architecture, &end, 10);
468     if (end == architecture) {
469       architecture_ = 0;
470     }
471     delete[] architecture;
472 
473     // Unfortunately, it seems that certain ARMv6-based CPUs
474     // report an incorrect architecture number of 7!
475     //
476     // See http://code.google.com/p/android/issues/detail?id=10812
477     //
478     // We try to correct this by looking at the 'elf_platform'
479     // field reported by the 'Processor' field, which is of the
480     // form of "(v7l)" for an ARMv7-based CPU, and "(v6l)" for
481     // an ARMv6-one. For example, the Raspberry Pi is one popular
482     // ARMv6 device that reports architecture 7.
483     if (architecture_ == 7) {
484       char* processor = cpu_info.ExtractField("Processor");
485       if (HasListItem(processor, "(v6l)")) {
486         architecture_ = 6;
487       }
488       delete[] processor;
489     }
490 
491     // elf_platform moved to the model name field in Linux v3.8.
492     if (architecture_ == 7) {
493       char* processor = cpu_info.ExtractField("model name");
494       if (HasListItem(processor, "(v6l)")) {
495         architecture_ = 6;
496       }
497       delete[] processor;
498     }
499   }
500 
501   // Try to extract the list of CPU features from ELF hwcaps.
502   uint32_t hwcaps = ReadELFHWCaps();
503   if (hwcaps != 0) {
504     has_idiva_ = (hwcaps & HWCAP_IDIVA) != 0;
505     has_neon_ = (hwcaps & HWCAP_NEON) != 0;
506     has_vfp_ = (hwcaps & HWCAP_VFP) != 0;
507     has_vfp3_ = (hwcaps & (HWCAP_VFPv3 | HWCAP_VFPv3D16 | HWCAP_VFPv4)) != 0;
508     has_vfp3_d32_ = (has_vfp3_ && ((hwcaps & HWCAP_VFPv3D16) == 0 ||
509                                    (hwcaps & HWCAP_VFPD32) != 0));
510   } else {
511     // Try to fallback to "Features" CPUInfo field.
512     char* features = cpu_info.ExtractField("Features");
513     has_idiva_ = HasListItem(features, "idiva");
514     has_neon_ = HasListItem(features, "neon");
515     has_thumb2_ = HasListItem(features, "thumb2");
516     has_vfp_ = HasListItem(features, "vfp");
517     if (HasListItem(features, "vfpv3d16")) {
518       has_vfp3_ = true;
519     } else if (HasListItem(features, "vfpv3")) {
520       has_vfp3_ = true;
521       has_vfp3_d32_ = true;
522     }
523     delete[] features;
524   }
525 
526   // Some old kernels will report vfp not vfpv3. Here we make an attempt
527   // to detect vfpv3 by checking for vfp *and* neon, since neon is only
528   // available on architectures with vfpv3. Checking neon on its own is
529   // not enough as it is possible to have neon without vfp.
530   if (has_vfp_ && has_neon_) {
531     has_vfp3_ = true;
532   }
533 
534   // VFPv3 implies ARMv7, see ARM DDI 0406B, page A1-6.
535   if (architecture_ < 7 && has_vfp3_) {
536     architecture_ = 7;
537   }
538 
539   // ARMv7 implies Thumb2.
540   if (architecture_ >= 7) {
541     has_thumb2_ = true;
542   }
543 
544   // The earliest architecture with Thumb2 is ARMv6T2.
545   if (has_thumb2_ && architecture_ < 6) {
546     architecture_ = 6;
547   }
548 
549   // We don't support any FPUs other than VFP.
550   has_fpu_ = has_vfp_;
551 
552 #elif V8_OS_QNX
553 
554   uint32_t cpu_flags = SYSPAGE_ENTRY(cpuinfo)->flags;
555   if (cpu_flags & ARM_CPU_FLAG_V7) {
556     architecture_ = 7;
557     has_thumb2_ = true;
558   } else if (cpu_flags & ARM_CPU_FLAG_V6) {
559     architecture_ = 6;
560     // QNX doesn't say if Thumb2 is available.
561     // Assume false for the architectures older than ARMv7.
562   }
563   DCHECK(architecture_ >= 6);
564   has_fpu_ = (cpu_flags & CPU_FLAG_FPU) != 0;
565   has_vfp_ = has_fpu_;
566   if (cpu_flags & ARM_CPU_FLAG_NEON) {
567     has_neon_ = true;
568     has_vfp3_ = has_vfp_;
569 #ifdef ARM_CPU_FLAG_VFP_D32
570     has_vfp3_d32_ = (cpu_flags & ARM_CPU_FLAG_VFP_D32) != 0;
571 #endif
572   }
573   has_idiva_ = (cpu_flags & ARM_CPU_FLAG_IDIV) != 0;
574 
575 #endif  // V8_OS_LINUX
576 
577 #elif V8_HOST_ARCH_MIPS || V8_HOST_ARCH_MIPS64
578 
579   // Simple detection of FPU at runtime for Linux.
580   // It is based on /proc/cpuinfo, which reveals hardware configuration
581   // to user-space applications.  According to MIPS (early 2010), no similar
582   // facility is universally available on the MIPS architectures,
583   // so it's up to individual OSes to provide such.
584   CPUInfo cpu_info;
585   char* cpu_model = cpu_info.ExtractField("cpu model");
586   has_fpu_ = HasListItem(cpu_model, "FPU");
587   delete[] cpu_model;
588 #ifdef V8_HOST_ARCH_MIPS
589   is_fp64_mode_ = __detect_fp64_mode();
590   architecture_ = __detect_mips_arch_revision();
591 #endif
592 
593 #elif V8_HOST_ARCH_ARM64
594 
595   CPUInfo cpu_info;
596 
597   // Extract implementor from the "CPU implementer" field.
598   char* implementer = cpu_info.ExtractField("CPU implementer");
599   if (implementer != NULL) {
600     char* end;
601     implementer_ = strtol(implementer, &end, 0);
602     if (end == implementer) {
603       implementer_ = 0;
604     }
605     delete[] implementer;
606   }
607 
608   char* variant = cpu_info.ExtractField("CPU variant");
609   if (variant != NULL) {
610     char* end;
611     variant_ = strtol(variant, &end, 0);
612     if (end == variant) {
613       variant_ = -1;
614     }
615     delete[] variant;
616   }
617 
618   // Extract part number from the "CPU part" field.
619   char* part = cpu_info.ExtractField("CPU part");
620   if (part != NULL) {
621     char* end;
622     part_ = strtol(part, &end, 0);
623     if (end == part) {
624       part_ = 0;
625     }
626     delete[] part;
627   }
628 
629 #elif V8_HOST_ARCH_PPC
630 
631 #ifndef USE_SIMULATOR
632 #if V8_OS_LINUX
633   // Read processor info from /proc/self/auxv.
634   char* auxv_cpu_type = NULL;
635   FILE* fp = fopen("/proc/self/auxv", "r");
636   if (fp != NULL) {
637 #if V8_TARGET_ARCH_PPC64
638     Elf64_auxv_t entry;
639 #else
640     Elf32_auxv_t entry;
641 #endif
642     for (;;) {
643       size_t n = fread(&entry, sizeof(entry), 1, fp);
644       if (n == 0 || entry.a_type == AT_NULL) {
645         break;
646       }
647       if (entry.a_type == AT_PLATFORM) {
648         auxv_cpu_type = reinterpret_cast<char*>(entry.a_un.a_val);
649         break;
650       }
651     }
652     fclose(fp);
653   }
654 
655   part_ = -1;
656   if (auxv_cpu_type) {
657     if (strcmp(auxv_cpu_type, "power8") == 0) {
658       part_ = PPC_POWER8;
659     } else if (strcmp(auxv_cpu_type, "power7") == 0) {
660       part_ = PPC_POWER7;
661     } else if (strcmp(auxv_cpu_type, "power6") == 0) {
662       part_ = PPC_POWER6;
663     } else if (strcmp(auxv_cpu_type, "power5") == 0) {
664       part_ = PPC_POWER5;
665     } else if (strcmp(auxv_cpu_type, "ppc970") == 0) {
666       part_ = PPC_G5;
667     } else if (strcmp(auxv_cpu_type, "ppc7450") == 0) {
668       part_ = PPC_G4;
669     } else if (strcmp(auxv_cpu_type, "pa6t") == 0) {
670       part_ = PPC_PA6T;
671     }
672   }
673 
674 #elif V8_OS_AIX
675   switch (_system_configuration.implementation) {
676     case POWER_8:
677       part_ = PPC_POWER8;
678       break;
679     case POWER_7:
680       part_ = PPC_POWER7;
681       break;
682     case POWER_6:
683       part_ = PPC_POWER6;
684       break;
685     case POWER_5:
686       part_ = PPC_POWER5;
687       break;
688   }
689 #endif  // V8_OS_AIX
690 #endif  // !USE_SIMULATOR
691 #endif  // V8_HOST_ARCH_PPC
692 }
693 
694 }  // namespace base
695 }  // namespace v8
696