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      1 /*
      2  * Copyright (C) 2010 The Android Open Source Project
      3  * All rights reserved.
      4  *
      5  * Redistribution and use in source and binary forms, with or without
      6  * modification, are permitted provided that the following conditions
      7  * are met:
      8  *  * Redistributions of source code must retain the above copyright
      9  *    notice, this list of conditions and the following disclaimer.
     10  *  * Redistributions in binary form must reproduce the above copyright
     11  *    notice, this list of conditions and the following disclaimer in
     12  *    the documentation and/or other materials provided with the
     13  *    distribution.
     14  *
     15  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
     16  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
     17  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
     18  * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
     19  * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
     20  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
     21  * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
     22  * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
     23  * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
     24  * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
     25  * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     26  * SUCH DAMAGE.
     27  */
     28 
     29 /* ChangeLog for this library:
     30  *
     31  * NDK r9?: Support for 64-bit CPUs (Intel, ARM & MIPS).
     32  *
     33  * NDK r8d: Add android_setCpu().
     34  *
     35  * NDK r8c: Add new ARM CPU features: VFPv2, VFP_D32, VFP_FP16,
     36  *          VFP_FMA, NEON_FMA, IDIV_ARM, IDIV_THUMB2 and iWMMXt.
     37  *
     38  *          Rewrite the code to parse /proc/self/auxv instead of
     39  *          the "Features" field in /proc/cpuinfo.
     40  *
     41  *          Dynamically allocate the buffer that hold the content
     42  *          of /proc/cpuinfo to deal with newer hardware.
     43  *
     44  * NDK r7c: Fix CPU count computation. The old method only reported the
     45  *           number of _active_ CPUs when the library was initialized,
     46  *           which could be less than the real total.
     47  *
     48  * NDK r5: Handle buggy kernels which report a CPU Architecture number of 7
     49  *         for an ARMv6 CPU (see below).
     50  *
     51  *         Handle kernels that only report 'neon', and not 'vfpv3'
     52  *         (VFPv3 is mandated by the ARM architecture is Neon is implemented)
     53  *
     54  *         Handle kernels that only report 'vfpv3d16', and not 'vfpv3'
     55  *
     56  *         Fix x86 compilation. Report ANDROID_CPU_FAMILY_X86 in
     57  *         android_getCpuFamily().
     58  *
     59  * NDK r4: Initial release
     60  */
     61 
     62 #if defined(__le32__) || defined(__le64__)
     63 
     64 // When users enter this, we should only provide interface and
     65 // libportable will give the implementations.
     66 
     67 #else // !__le32__ && !__le64__
     68 
     69 #include "cpu-features.h"
     70 
     71 #include <dlfcn.h>
     72 #include <errno.h>
     73 #include <fcntl.h>
     74 #include <pthread.h>
     75 #include <stdio.h>
     76 #include <stdlib.h>
     77 #include <sys/system_properties.h>
     78 
     79 static  pthread_once_t     g_once;
     80 static  int                g_inited;
     81 static  AndroidCpuFamily   g_cpuFamily;
     82 static  uint64_t           g_cpuFeatures;
     83 static  int                g_cpuCount;
     84 
     85 #ifdef __arm__
     86 static  uint32_t           g_cpuIdArm;
     87 #endif
     88 
     89 static const int android_cpufeatures_debug = 0;
     90 
     91 #define  D(...) \
     92     do { \
     93         if (android_cpufeatures_debug) { \
     94             printf(__VA_ARGS__); fflush(stdout); \
     95         } \
     96     } while (0)
     97 
     98 #ifdef __i386__
     99 static __inline__ void x86_cpuid(int func, int values[4])
    100 {
    101     int a, b, c, d;
    102     /* We need to preserve ebx since we're compiling PIC code */
    103     /* this means we can't use "=b" for the second output register */
    104     __asm__ __volatile__ ( \
    105       "push %%ebx\n"
    106       "cpuid\n" \
    107       "mov %%ebx, %1\n"
    108       "pop %%ebx\n"
    109       : "=a" (a), "=r" (b), "=c" (c), "=d" (d) \
    110       : "a" (func) \
    111     );
    112     values[0] = a;
    113     values[1] = b;
    114     values[2] = c;
    115     values[3] = d;
    116 }
    117 #endif
    118 
    119 /* Get the size of a file by reading it until the end. This is needed
    120  * because files under /proc do not always return a valid size when
    121  * using fseek(0, SEEK_END) + ftell(). Nor can they be mmap()-ed.
    122  */
    123 static int
    124 get_file_size(const char* pathname)
    125 {
    126     int fd, ret, result = 0;
    127     char buffer[256];
    128 
    129     fd = open(pathname, O_RDONLY);
    130     if (fd < 0) {
    131         D("Can't open %s: %s\n", pathname, strerror(errno));
    132         return -1;
    133     }
    134 
    135     for (;;) {
    136         int ret = read(fd, buffer, sizeof buffer);
    137         if (ret < 0) {
    138             if (errno == EINTR)
    139                 continue;
    140             D("Error while reading %s: %s\n", pathname, strerror(errno));
    141             break;
    142         }
    143         if (ret == 0)
    144             break;
    145 
    146         result += ret;
    147     }
    148     close(fd);
    149     return result;
    150 }
    151 
    152 /* Read the content of /proc/cpuinfo into a user-provided buffer.
    153  * Return the length of the data, or -1 on error. Does *not*
    154  * zero-terminate the content. Will not read more
    155  * than 'buffsize' bytes.
    156  */
    157 static int
    158 read_file(const char*  pathname, char*  buffer, size_t  buffsize)
    159 {
    160     int  fd, count;
    161 
    162     fd = open(pathname, O_RDONLY);
    163     if (fd < 0) {
    164         D("Could not open %s: %s\n", pathname, strerror(errno));
    165         return -1;
    166     }
    167     count = 0;
    168     while (count < (int)buffsize) {
    169         int ret = read(fd, buffer + count, buffsize - count);
    170         if (ret < 0) {
    171             if (errno == EINTR)
    172                 continue;
    173             D("Error while reading from %s: %s\n", pathname, strerror(errno));
    174             if (count == 0)
    175                 count = -1;
    176             break;
    177         }
    178         if (ret == 0)
    179             break;
    180         count += ret;
    181     }
    182     close(fd);
    183     return count;
    184 }
    185 
    186 /* Extract the content of a the first occurence of a given field in
    187  * the content of /proc/cpuinfo and return it as a heap-allocated
    188  * string that must be freed by the caller.
    189  *
    190  * Return NULL if not found
    191  */
    192 static char*
    193 extract_cpuinfo_field(const char* buffer, int buflen, const char* field)
    194 {
    195     int  fieldlen = strlen(field);
    196     const char* bufend = buffer + buflen;
    197     char* result = NULL;
    198     int len, ignore;
    199     const char *p, *q;
    200 
    201     /* Look for first field occurence, and ensures it starts the line. */
    202     p = buffer;
    203     for (;;) {
    204         p = memmem(p, bufend-p, field, fieldlen);
    205         if (p == NULL)
    206             goto EXIT;
    207 
    208         if (p == buffer || p[-1] == '\n')
    209             break;
    210 
    211         p += fieldlen;
    212     }
    213 
    214     /* Skip to the first column followed by a space */
    215     p += fieldlen;
    216     p  = memchr(p, ':', bufend-p);
    217     if (p == NULL || p[1] != ' ')
    218         goto EXIT;
    219 
    220     /* Find the end of the line */
    221     p += 2;
    222     q = memchr(p, '\n', bufend-p);
    223     if (q == NULL)
    224         q = bufend;
    225 
    226     /* Copy the line into a heap-allocated buffer */
    227     len = q-p;
    228     result = malloc(len+1);
    229     if (result == NULL)
    230         goto EXIT;
    231 
    232     memcpy(result, p, len);
    233     result[len] = '\0';
    234 
    235 EXIT:
    236     return result;
    237 }
    238 
    239 /* Checks that a space-separated list of items contains one given 'item'.
    240  * Returns 1 if found, 0 otherwise.
    241  */
    242 static int
    243 has_list_item(const char* list, const char* item)
    244 {
    245     const char*  p = list;
    246     int itemlen = strlen(item);
    247 
    248     if (list == NULL)
    249         return 0;
    250 
    251     while (*p) {
    252         const char*  q;
    253 
    254         /* skip spaces */
    255         while (*p == ' ' || *p == '\t')
    256             p++;
    257 
    258         /* find end of current list item */
    259         q = p;
    260         while (*q && *q != ' ' && *q != '\t')
    261             q++;
    262 
    263         if (itemlen == q-p && !memcmp(p, item, itemlen))
    264             return 1;
    265 
    266         /* skip to next item */
    267         p = q;
    268     }
    269     return 0;
    270 }
    271 
    272 /* Parse a number starting from 'input', but not going further
    273  * than 'limit'. Return the value into '*result'.
    274  *
    275  * NOTE: Does not skip over leading spaces, or deal with sign characters.
    276  * NOTE: Ignores overflows.
    277  *
    278  * The function returns NULL in case of error (bad format), or the new
    279  * position after the decimal number in case of success (which will always
    280  * be <= 'limit').
    281  */
    282 static const char*
    283 parse_number(const char* input, const char* limit, int base, int* result)
    284 {
    285     const char* p = input;
    286     int val = 0;
    287     while (p < limit) {
    288         int d = (*p - '0');
    289         if ((unsigned)d >= 10U) {
    290             d = (*p - 'a');
    291             if ((unsigned)d >= 6U)
    292               d = (*p - 'A');
    293             if ((unsigned)d >= 6U)
    294               break;
    295             d += 10;
    296         }
    297         if (d >= base)
    298           break;
    299         val = val*base + d;
    300         p++;
    301     }
    302     if (p == input)
    303         return NULL;
    304 
    305     *result = val;
    306     return p;
    307 }
    308 
    309 static const char*
    310 parse_decimal(const char* input, const char* limit, int* result)
    311 {
    312     return parse_number(input, limit, 10, result);
    313 }
    314 
    315 static const char*
    316 parse_hexadecimal(const char* input, const char* limit, int* result)
    317 {
    318     return parse_number(input, limit, 16, result);
    319 }
    320 
    321 /* This small data type is used to represent a CPU list / mask, as read
    322  * from sysfs on Linux. See http://www.kernel.org/doc/Documentation/cputopology.txt
    323  *
    324  * For now, we don't expect more than 32 cores on mobile devices, so keep
    325  * everything simple.
    326  */
    327 typedef struct {
    328     uint32_t mask;
    329 } CpuList;
    330 
    331 static __inline__ void
    332 cpulist_init(CpuList* list) {
    333     list->mask = 0;
    334 }
    335 
    336 static __inline__ void
    337 cpulist_and(CpuList* list1, CpuList* list2) {
    338     list1->mask &= list2->mask;
    339 }
    340 
    341 static __inline__ void
    342 cpulist_set(CpuList* list, int index) {
    343     if ((unsigned)index < 32) {
    344         list->mask |= (uint32_t)(1U << index);
    345     }
    346 }
    347 
    348 static __inline__ int
    349 cpulist_count(CpuList* list) {
    350     return __builtin_popcount(list->mask);
    351 }
    352 
    353 /* Parse a textual list of cpus and store the result inside a CpuList object.
    354  * Input format is the following:
    355  * - comma-separated list of items (no spaces)
    356  * - each item is either a single decimal number (cpu index), or a range made
    357  *   of two numbers separated by a single dash (-). Ranges are inclusive.
    358  *
    359  * Examples:   0
    360  *             2,4-127,128-143
    361  *             0-1
    362  */
    363 static void
    364 cpulist_parse(CpuList* list, const char* line, int line_len)
    365 {
    366     const char* p = line;
    367     const char* end = p + line_len;
    368     const char* q;
    369 
    370     /* NOTE: the input line coming from sysfs typically contains a
    371      * trailing newline, so take care of it in the code below
    372      */
    373     while (p < end && *p != '\n')
    374     {
    375         int val, start_value, end_value;
    376 
    377         /* Find the end of current item, and put it into 'q' */
    378         q = memchr(p, ',', end-p);
    379         if (q == NULL) {
    380             q = end;
    381         }
    382 
    383         /* Get first value */
    384         p = parse_decimal(p, q, &start_value);
    385         if (p == NULL)
    386             goto BAD_FORMAT;
    387 
    388         end_value = start_value;
    389 
    390         /* If we're not at the end of the item, expect a dash and
    391          * and integer; extract end value.
    392          */
    393         if (p < q && *p == '-') {
    394             p = parse_decimal(p+1, q, &end_value);
    395             if (p == NULL)
    396                 goto BAD_FORMAT;
    397         }
    398 
    399         /* Set bits CPU list bits */
    400         for (val = start_value; val <= end_value; val++) {
    401             cpulist_set(list, val);
    402         }
    403 
    404         /* Jump to next item */
    405         p = q;
    406         if (p < end)
    407             p++;
    408     }
    409 
    410 BAD_FORMAT:
    411     ;
    412 }
    413 
    414 /* Read a CPU list from one sysfs file */
    415 static void
    416 cpulist_read_from(CpuList* list, const char* filename)
    417 {
    418     char   file[64];
    419     int    filelen;
    420 
    421     cpulist_init(list);
    422 
    423     filelen = read_file(filename, file, sizeof file);
    424     if (filelen < 0) {
    425         D("Could not read %s: %s\n", filename, strerror(errno));
    426         return;
    427     }
    428 
    429     cpulist_parse(list, file, filelen);
    430 }
    431 #if defined(__aarch64__)
    432 // see <uapi/asm/hwcap.h> kernel header
    433 #define HWCAP_FP                (1 << 0)
    434 #define HWCAP_ASIMD             (1 << 1)
    435 #define HWCAP_AES               (1 << 3)
    436 #define HWCAP_PMULL             (1 << 4)
    437 #define HWCAP_SHA1              (1 << 5)
    438 #define HWCAP_SHA2              (1 << 6)
    439 #define HWCAP_CRC32             (1 << 7)
    440 #endif
    441 
    442 #if defined(__arm__)
    443 
    444 // See <asm/hwcap.h> kernel header.
    445 #define HWCAP_VFP       (1 << 6)
    446 #define HWCAP_IWMMXT    (1 << 9)
    447 #define HWCAP_NEON      (1 << 12)
    448 #define HWCAP_VFPv3     (1 << 13)
    449 #define HWCAP_VFPv3D16  (1 << 14)
    450 #define HWCAP_VFPv4     (1 << 16)
    451 #define HWCAP_IDIVA     (1 << 17)
    452 #define HWCAP_IDIVT     (1 << 18)
    453 
    454 // see <uapi/asm/hwcap.h> kernel header
    455 #define HWCAP2_AES     (1 << 0)
    456 #define HWCAP2_PMULL   (1 << 1)
    457 #define HWCAP2_SHA1    (1 << 2)
    458 #define HWCAP2_SHA2    (1 << 3)
    459 #define HWCAP2_CRC32   (1 << 4)
    460 
    461 // This is the list of 32-bit ARMv7 optional features that are _always_
    462 // supported by ARMv8 CPUs, as mandated by the ARM Architecture Reference
    463 // Manual.
    464 #define HWCAP_SET_FOR_ARMV8  \
    465   ( HWCAP_VFP | \
    466     HWCAP_NEON | \
    467     HWCAP_VFPv3 | \
    468     HWCAP_VFPv4 | \
    469     HWCAP_IDIVA | \
    470     HWCAP_IDIVT )
    471 #endif
    472 
    473 #if defined(__arm__) || defined(__aarch64__)
    474 
    475 #define AT_HWCAP 16
    476 #define AT_HWCAP2 26
    477 
    478 // Probe the system's C library for a 'getauxval' function and call it if
    479 // it exits, or return 0 for failure. This function is available since API
    480 // level 20.
    481 //
    482 // This code does *NOT* check for '__ANDROID_API__ >= 20' to support the
    483 // edge case where some NDK developers use headers for a platform that is
    484 // newer than the one really targetted by their application.
    485 // This is typically done to use newer native APIs only when running on more
    486 // recent Android versions, and requires careful symbol management.
    487 //
    488 // Note that getauxval() can't really be re-implemented here, because
    489 // its implementation does not parse /proc/self/auxv. Instead it depends
    490 // on values  that are passed by the kernel at process-init time to the
    491 // C runtime initialization layer.
    492 static uint32_t
    493 get_elf_hwcap_from_getauxval(int hwcap_type) {
    494     typedef unsigned long getauxval_func_t(unsigned long);
    495 
    496     dlerror();
    497     void* libc_handle = dlopen("libc.so", RTLD_NOW);
    498     if (!libc_handle) {
    499         D("Could not dlopen() C library: %s\n", dlerror());
    500         return 0;
    501     }
    502 
    503     uint32_t ret = 0;
    504     getauxval_func_t* func = (getauxval_func_t*)
    505             dlsym(libc_handle, "getauxval");
    506     if (!func) {
    507         D("Could not find getauxval() in C library\n");
    508     } else {
    509         // Note: getauxval() returns 0 on failure. Doesn't touch errno.
    510         ret = (uint32_t)(*func)(hwcap_type);
    511     }
    512     dlclose(libc_handle);
    513     return ret;
    514 }
    515 #endif
    516 
    517 #if defined(__arm__)
    518 // Parse /proc/self/auxv to extract the ELF HW capabilities bitmap for the
    519 // current CPU. Note that this file is not accessible from regular
    520 // application processes on some Android platform releases.
    521 // On success, return new ELF hwcaps, or 0 on failure.
    522 static uint32_t
    523 get_elf_hwcap_from_proc_self_auxv(void) {
    524     const char filepath[] = "/proc/self/auxv";
    525     int fd = TEMP_FAILURE_RETRY(open(filepath, O_RDONLY));
    526     if (fd < 0) {
    527         D("Could not open %s: %s\n", filepath, strerror(errno));
    528         return 0;
    529     }
    530 
    531     struct { uint32_t tag; uint32_t value; } entry;
    532 
    533     uint32_t result = 0;
    534     for (;;) {
    535         int ret = TEMP_FAILURE_RETRY(read(fd, (char*)&entry, sizeof entry));
    536         if (ret < 0) {
    537             D("Error while reading %s: %s\n", filepath, strerror(errno));
    538             break;
    539         }
    540         // Detect end of list.
    541         if (ret == 0 || (entry.tag == 0 && entry.value == 0))
    542           break;
    543         if (entry.tag == AT_HWCAP) {
    544           result = entry.value;
    545           break;
    546         }
    547     }
    548     close(fd);
    549     return result;
    550 }
    551 
    552 /* Compute the ELF HWCAP flags from the content of /proc/cpuinfo.
    553  * This works by parsing the 'Features' line, which lists which optional
    554  * features the device's CPU supports, on top of its reference
    555  * architecture.
    556  */
    557 static uint32_t
    558 get_elf_hwcap_from_proc_cpuinfo(const char* cpuinfo, int cpuinfo_len) {
    559     uint32_t hwcaps = 0;
    560     long architecture = 0;
    561     char* cpuArch = extract_cpuinfo_field(cpuinfo, cpuinfo_len, "CPU architecture");
    562     if (cpuArch) {
    563         architecture = strtol(cpuArch, NULL, 10);
    564         free(cpuArch);
    565 
    566         if (architecture >= 8L) {
    567             // This is a 32-bit ARM binary running on a 64-bit ARM64 kernel.
    568             // The 'Features' line only lists the optional features that the
    569             // device's CPU supports, compared to its reference architecture
    570             // which are of no use for this process.
    571             D("Faking 32-bit ARM HWCaps on ARMv%ld CPU\n", architecture);
    572             return HWCAP_SET_FOR_ARMV8;
    573         }
    574     }
    575 
    576     char* cpuFeatures = extract_cpuinfo_field(cpuinfo, cpuinfo_len, "Features");
    577     if (cpuFeatures != NULL) {
    578         D("Found cpuFeatures = '%s'\n", cpuFeatures);
    579 
    580         if (has_list_item(cpuFeatures, "vfp"))
    581             hwcaps |= HWCAP_VFP;
    582         if (has_list_item(cpuFeatures, "vfpv3"))
    583             hwcaps |= HWCAP_VFPv3;
    584         if (has_list_item(cpuFeatures, "vfpv3d16"))
    585             hwcaps |= HWCAP_VFPv3D16;
    586         if (has_list_item(cpuFeatures, "vfpv4"))
    587             hwcaps |= HWCAP_VFPv4;
    588         if (has_list_item(cpuFeatures, "neon"))
    589             hwcaps |= HWCAP_NEON;
    590         if (has_list_item(cpuFeatures, "idiva"))
    591             hwcaps |= HWCAP_IDIVA;
    592         if (has_list_item(cpuFeatures, "idivt"))
    593             hwcaps |= HWCAP_IDIVT;
    594         if (has_list_item(cpuFeatures, "idiv"))
    595             hwcaps |= HWCAP_IDIVA | HWCAP_IDIVT;
    596         if (has_list_item(cpuFeatures, "iwmmxt"))
    597             hwcaps |= HWCAP_IWMMXT;
    598 
    599         free(cpuFeatures);
    600     }
    601     return hwcaps;
    602 }
    603 
    604 /* Check Houdini Binary Translator is installed on the system.
    605  *
    606  * If this function returns 1, get_elf_hwcap_from_getauxval() function
    607  * will causes SIGSEGV while calling getauxval() function.
    608  */
    609 static int
    610 has_houdini_binary_translator(void) {
    611     int found = 0;
    612     if (access("/system/lib/libhoudini.so", F_OK) != -1) {
    613         D("Found Houdini binary translator\n");
    614         found = 1;
    615     }
    616     return found;
    617 }
    618 #endif  /* __arm__ */
    619 
    620 /* Return the number of cpus present on a given device.
    621  *
    622  * To handle all weird kernel configurations, we need to compute the
    623  * intersection of the 'present' and 'possible' CPU lists and count
    624  * the result.
    625  */
    626 static int
    627 get_cpu_count(void)
    628 {
    629     CpuList cpus_present[1];
    630     CpuList cpus_possible[1];
    631 
    632     cpulist_read_from(cpus_present, "/sys/devices/system/cpu/present");
    633     cpulist_read_from(cpus_possible, "/sys/devices/system/cpu/possible");
    634 
    635     /* Compute the intersection of both sets to get the actual number of
    636      * CPU cores that can be used on this device by the kernel.
    637      */
    638     cpulist_and(cpus_present, cpus_possible);
    639 
    640     return cpulist_count(cpus_present);
    641 }
    642 
    643 static void
    644 android_cpuInitFamily(void)
    645 {
    646 #if defined(__arm__)
    647     g_cpuFamily = ANDROID_CPU_FAMILY_ARM;
    648 #elif defined(__i386__)
    649     g_cpuFamily = ANDROID_CPU_FAMILY_X86;
    650 #elif defined(__mips64)
    651 /* Needs to be before __mips__ since the compiler defines both */
    652     g_cpuFamily = ANDROID_CPU_FAMILY_MIPS64;
    653 #elif defined(__mips__)
    654     g_cpuFamily = ANDROID_CPU_FAMILY_MIPS;
    655 #elif defined(__aarch64__)
    656     g_cpuFamily = ANDROID_CPU_FAMILY_ARM64;
    657 #elif defined(__x86_64__)
    658     g_cpuFamily = ANDROID_CPU_FAMILY_X86_64;
    659 #else
    660     g_cpuFamily = ANDROID_CPU_FAMILY_UNKNOWN;
    661 #endif
    662 }
    663 
    664 static void
    665 android_cpuInit(void)
    666 {
    667     char* cpuinfo = NULL;
    668     int   cpuinfo_len;
    669 
    670     android_cpuInitFamily();
    671 
    672     g_cpuFeatures = 0;
    673     g_cpuCount    = 1;
    674     g_inited      = 1;
    675 
    676     cpuinfo_len = get_file_size("/proc/cpuinfo");
    677     if (cpuinfo_len < 0) {
    678       D("cpuinfo_len cannot be computed!");
    679       return;
    680     }
    681     cpuinfo = malloc(cpuinfo_len);
    682     if (cpuinfo == NULL) {
    683       D("cpuinfo buffer could not be allocated");
    684       return;
    685     }
    686     cpuinfo_len = read_file("/proc/cpuinfo", cpuinfo, cpuinfo_len);
    687     D("cpuinfo_len is (%d):\n%.*s\n", cpuinfo_len,
    688       cpuinfo_len >= 0 ? cpuinfo_len : 0, cpuinfo);
    689 
    690     if (cpuinfo_len < 0)  /* should not happen */ {
    691         free(cpuinfo);
    692         return;
    693     }
    694 
    695     /* Count the CPU cores, the value may be 0 for single-core CPUs */
    696     g_cpuCount = get_cpu_count();
    697     if (g_cpuCount == 0) {
    698         g_cpuCount = 1;
    699     }
    700 
    701     D("found cpuCount = %d\n", g_cpuCount);
    702 
    703 #ifdef __arm__
    704     {
    705         /* Extract architecture from the "CPU Architecture" field.
    706          * The list is well-known, unlike the the output of
    707          * the 'Processor' field which can vary greatly.
    708          *
    709          * See the definition of the 'proc_arch' array in
    710          * $KERNEL/arch/arm/kernel/setup.c and the 'c_show' function in
    711          * same file.
    712          */
    713         char* cpuArch = extract_cpuinfo_field(cpuinfo, cpuinfo_len, "CPU architecture");
    714 
    715         if (cpuArch != NULL) {
    716             char*  end;
    717             long   archNumber;
    718             int    hasARMv7 = 0;
    719 
    720             D("found cpuArch = '%s'\n", cpuArch);
    721 
    722             /* read the initial decimal number, ignore the rest */
    723             archNumber = strtol(cpuArch, &end, 10);
    724 
    725             /* Note that ARMv8 is upwards compatible with ARMv7. */
    726             if (end > cpuArch && archNumber >= 7) {
    727                 hasARMv7 = 1;
    728             }
    729 
    730             /* Unfortunately, it seems that certain ARMv6-based CPUs
    731              * report an incorrect architecture number of 7!
    732              *
    733              * See http://code.google.com/p/android/issues/detail?id=10812
    734              *
    735              * We try to correct this by looking at the 'elf_format'
    736              * field reported by the 'Processor' field, which is of the
    737              * form of "(v7l)" for an ARMv7-based CPU, and "(v6l)" for
    738              * an ARMv6-one.
    739              */
    740             if (hasARMv7) {
    741                 char* cpuProc = extract_cpuinfo_field(cpuinfo, cpuinfo_len,
    742                                                       "Processor");
    743                 if (cpuProc != NULL) {
    744                     D("found cpuProc = '%s'\n", cpuProc);
    745                     if (has_list_item(cpuProc, "(v6l)")) {
    746                         D("CPU processor and architecture mismatch!!\n");
    747                         hasARMv7 = 0;
    748                     }
    749                     free(cpuProc);
    750                 }
    751             }
    752 
    753             if (hasARMv7) {
    754                 g_cpuFeatures |= ANDROID_CPU_ARM_FEATURE_ARMv7;
    755             }
    756 
    757             /* The LDREX / STREX instructions are available from ARMv6 */
    758             if (archNumber >= 6) {
    759                 g_cpuFeatures |= ANDROID_CPU_ARM_FEATURE_LDREX_STREX;
    760             }
    761 
    762             free(cpuArch);
    763         }
    764 
    765         /* Check Houdini binary translator is installed */
    766         int has_houdini = has_houdini_binary_translator();
    767 
    768         /* Extract the list of CPU features from ELF hwcaps */
    769         uint32_t hwcaps = 0;
    770         if (!has_houdini) {
    771             hwcaps = get_elf_hwcap_from_getauxval(AT_HWCAP);
    772         }
    773         if (!hwcaps) {
    774             D("Parsing /proc/self/auxv to extract ELF hwcaps!\n");
    775             hwcaps = get_elf_hwcap_from_proc_self_auxv();
    776         }
    777         if (!hwcaps) {
    778             // Parsing /proc/self/auxv will fail from regular application
    779             // processes on some Android platform versions, when this happens
    780             // parse proc/cpuinfo instead.
    781             D("Parsing /proc/cpuinfo to extract ELF hwcaps!\n");
    782             hwcaps = get_elf_hwcap_from_proc_cpuinfo(cpuinfo, cpuinfo_len);
    783         }
    784 
    785         if (hwcaps != 0) {
    786             int has_vfp = (hwcaps & HWCAP_VFP);
    787             int has_vfpv3 = (hwcaps & HWCAP_VFPv3);
    788             int has_vfpv3d16 = (hwcaps & HWCAP_VFPv3D16);
    789             int has_vfpv4 = (hwcaps & HWCAP_VFPv4);
    790             int has_neon = (hwcaps & HWCAP_NEON);
    791             int has_idiva = (hwcaps & HWCAP_IDIVA);
    792             int has_idivt = (hwcaps & HWCAP_IDIVT);
    793             int has_iwmmxt = (hwcaps & HWCAP_IWMMXT);
    794 
    795             // The kernel does a poor job at ensuring consistency when
    796             // describing CPU features. So lots of guessing is needed.
    797 
    798             // 'vfpv4' implies VFPv3|VFP_FMA|FP16
    799             if (has_vfpv4)
    800                 g_cpuFeatures |= ANDROID_CPU_ARM_FEATURE_VFPv3    |
    801                                  ANDROID_CPU_ARM_FEATURE_VFP_FP16 |
    802                                  ANDROID_CPU_ARM_FEATURE_VFP_FMA;
    803 
    804             // 'vfpv3' or 'vfpv3d16' imply VFPv3. Note that unlike GCC,
    805             // a value of 'vfpv3' doesn't necessarily mean that the D32
    806             // feature is present, so be conservative. All CPUs in the
    807             // field that support D32 also support NEON, so this should
    808             // not be a problem in practice.
    809             if (has_vfpv3 || has_vfpv3d16)
    810                 g_cpuFeatures |= ANDROID_CPU_ARM_FEATURE_VFPv3;
    811 
    812             // 'vfp' is super ambiguous. Depending on the kernel, it can
    813             // either mean VFPv2 or VFPv3. Make it depend on ARMv7.
    814             if (has_vfp) {
    815               if (g_cpuFeatures & ANDROID_CPU_ARM_FEATURE_ARMv7)
    816                   g_cpuFeatures |= ANDROID_CPU_ARM_FEATURE_VFPv3;
    817               else
    818                   g_cpuFeatures |= ANDROID_CPU_ARM_FEATURE_VFPv2;
    819             }
    820 
    821             // Neon implies VFPv3|D32, and if vfpv4 is detected, NEON_FMA
    822             if (has_neon) {
    823                 g_cpuFeatures |= ANDROID_CPU_ARM_FEATURE_VFPv3 |
    824                                  ANDROID_CPU_ARM_FEATURE_NEON |
    825                                  ANDROID_CPU_ARM_FEATURE_VFP_D32;
    826               if (has_vfpv4)
    827                   g_cpuFeatures |= ANDROID_CPU_ARM_FEATURE_NEON_FMA;
    828             }
    829 
    830             // VFPv3 implies VFPv2 and ARMv7
    831             if (g_cpuFeatures & ANDROID_CPU_ARM_FEATURE_VFPv3)
    832                 g_cpuFeatures |= ANDROID_CPU_ARM_FEATURE_VFPv2 |
    833                                  ANDROID_CPU_ARM_FEATURE_ARMv7;
    834 
    835             if (has_idiva)
    836                 g_cpuFeatures |= ANDROID_CPU_ARM_FEATURE_IDIV_ARM;
    837             if (has_idivt)
    838                 g_cpuFeatures |= ANDROID_CPU_ARM_FEATURE_IDIV_THUMB2;
    839 
    840             if (has_iwmmxt)
    841                 g_cpuFeatures |= ANDROID_CPU_ARM_FEATURE_iWMMXt;
    842         }
    843 
    844         /* Extract the list of CPU features from ELF hwcaps2 */
    845         uint32_t hwcaps2 = 0;
    846         if (!has_houdini) {
    847             hwcaps2 = get_elf_hwcap_from_getauxval(AT_HWCAP2);
    848         }
    849         if (hwcaps2 != 0) {
    850             int has_aes     = (hwcaps2 & HWCAP2_AES);
    851             int has_pmull   = (hwcaps2 & HWCAP2_PMULL);
    852             int has_sha1    = (hwcaps2 & HWCAP2_SHA1);
    853             int has_sha2    = (hwcaps2 & HWCAP2_SHA2);
    854             int has_crc32   = (hwcaps2 & HWCAP2_CRC32);
    855 
    856             if (has_aes)
    857                 g_cpuFeatures |= ANDROID_CPU_ARM_FEATURE_AES;
    858             if (has_pmull)
    859                 g_cpuFeatures |= ANDROID_CPU_ARM_FEATURE_PMULL;
    860             if (has_sha1)
    861                 g_cpuFeatures |= ANDROID_CPU_ARM_FEATURE_SHA1;
    862             if (has_sha2)
    863                 g_cpuFeatures |= ANDROID_CPU_ARM_FEATURE_SHA2;
    864             if (has_crc32)
    865                 g_cpuFeatures |= ANDROID_CPU_ARM_FEATURE_CRC32;
    866         }
    867         /* Extract the cpuid value from various fields */
    868         // The CPUID value is broken up in several entries in /proc/cpuinfo.
    869         // This table is used to rebuild it from the entries.
    870         static const struct CpuIdEntry {
    871             const char* field;
    872             char        format;
    873             char        bit_lshift;
    874             char        bit_length;
    875         } cpu_id_entries[] = {
    876             { "CPU implementer", 'x', 24, 8 },
    877             { "CPU variant", 'x', 20, 4 },
    878             { "CPU part", 'x', 4, 12 },
    879             { "CPU revision", 'd', 0, 4 },
    880         };
    881         size_t i;
    882         D("Parsing /proc/cpuinfo to recover CPUID\n");
    883         for (i = 0;
    884              i < sizeof(cpu_id_entries)/sizeof(cpu_id_entries[0]);
    885              ++i) {
    886             const struct CpuIdEntry* entry = &cpu_id_entries[i];
    887             char* value = extract_cpuinfo_field(cpuinfo,
    888                                                 cpuinfo_len,
    889                                                 entry->field);
    890             if (value == NULL)
    891                 continue;
    892 
    893             D("field=%s value='%s'\n", entry->field, value);
    894             char* value_end = value + strlen(value);
    895             int val = 0;
    896             const char* start = value;
    897             const char* p;
    898             if (value[0] == '0' && (value[1] == 'x' || value[1] == 'X')) {
    899               start += 2;
    900               p = parse_hexadecimal(start, value_end, &val);
    901             } else if (entry->format == 'x')
    902               p = parse_hexadecimal(value, value_end, &val);
    903             else
    904               p = parse_decimal(value, value_end, &val);
    905 
    906             if (p > (const char*)start) {
    907               val &= ((1 << entry->bit_length)-1);
    908               val <<= entry->bit_lshift;
    909               g_cpuIdArm |= (uint32_t) val;
    910             }
    911 
    912             free(value);
    913         }
    914 
    915         // Handle kernel configuration bugs that prevent the correct
    916         // reporting of CPU features.
    917         static const struct CpuFix {
    918             uint32_t  cpuid;
    919             uint64_t  or_flags;
    920         } cpu_fixes[] = {
    921             /* The Nexus 4 (Qualcomm Krait) kernel configuration
    922              * forgets to report IDIV support. */
    923             { 0x510006f2, ANDROID_CPU_ARM_FEATURE_IDIV_ARM |
    924                           ANDROID_CPU_ARM_FEATURE_IDIV_THUMB2 },
    925             { 0x510006f3, ANDROID_CPU_ARM_FEATURE_IDIV_ARM |
    926                           ANDROID_CPU_ARM_FEATURE_IDIV_THUMB2 },
    927         };
    928         size_t n;
    929         for (n = 0; n < sizeof(cpu_fixes)/sizeof(cpu_fixes[0]); ++n) {
    930             const struct CpuFix* entry = &cpu_fixes[n];
    931 
    932             if (g_cpuIdArm == entry->cpuid)
    933                 g_cpuFeatures |= entry->or_flags;
    934         }
    935 
    936         // Special case: The emulator-specific Android 4.2 kernel fails
    937         // to report support for the 32-bit ARM IDIV instruction.
    938         // Technically, this is a feature of the virtual CPU implemented
    939         // by the emulator. Note that it could also support Thumb IDIV
    940         // in the future, and this will have to be slightly updated.
    941         char* hardware = extract_cpuinfo_field(cpuinfo,
    942                                                cpuinfo_len,
    943                                                "Hardware");
    944         if (hardware) {
    945             if (!strcmp(hardware, "Goldfish") &&
    946                 g_cpuIdArm == 0x4100c080 &&
    947                 (g_cpuFamily & ANDROID_CPU_ARM_FEATURE_ARMv7) != 0) {
    948                 g_cpuFeatures |= ANDROID_CPU_ARM_FEATURE_IDIV_ARM;
    949             }
    950             free(hardware);
    951         }
    952     }
    953 #endif /* __arm__ */
    954 #ifdef __aarch64__
    955     {
    956         /* Extract the list of CPU features from ELF hwcaps */
    957         uint32_t hwcaps = 0;
    958         hwcaps = get_elf_hwcap_from_getauxval(AT_HWCAP);
    959         if (hwcaps != 0) {
    960             int has_fp      = (hwcaps & HWCAP_FP);
    961             int has_asimd   = (hwcaps & HWCAP_ASIMD);
    962             int has_aes     = (hwcaps & HWCAP_AES);
    963             int has_pmull   = (hwcaps & HWCAP_PMULL);
    964             int has_sha1    = (hwcaps & HWCAP_SHA1);
    965             int has_sha2    = (hwcaps & HWCAP_SHA2);
    966             int has_crc32   = (hwcaps & HWCAP_CRC32);
    967 
    968             if(has_fp == 0) {
    969                 D("ERROR: Floating-point unit missing, but is required by Android on AArch64 CPUs\n");
    970             }
    971             if(has_asimd == 0) {
    972                 D("ERROR: ASIMD unit missing, but is required by Android on AArch64 CPUs\n");
    973             }
    974 
    975             if (has_fp)
    976                 g_cpuFeatures |= ANDROID_CPU_ARM64_FEATURE_FP;
    977             if (has_asimd)
    978                 g_cpuFeatures |= ANDROID_CPU_ARM64_FEATURE_ASIMD;
    979             if (has_aes)
    980                 g_cpuFeatures |= ANDROID_CPU_ARM64_FEATURE_AES;
    981             if (has_pmull)
    982                 g_cpuFeatures |= ANDROID_CPU_ARM64_FEATURE_PMULL;
    983             if (has_sha1)
    984                 g_cpuFeatures |= ANDROID_CPU_ARM64_FEATURE_SHA1;
    985             if (has_sha2)
    986                 g_cpuFeatures |= ANDROID_CPU_ARM64_FEATURE_SHA2;
    987             if (has_crc32)
    988                 g_cpuFeatures |= ANDROID_CPU_ARM64_FEATURE_CRC32;
    989         }
    990     }
    991 #endif /* __aarch64__ */
    992 
    993 #ifdef __i386__
    994     int regs[4];
    995 
    996 /* According to http://en.wikipedia.org/wiki/CPUID */
    997 #define VENDOR_INTEL_b  0x756e6547
    998 #define VENDOR_INTEL_c  0x6c65746e
    999 #define VENDOR_INTEL_d  0x49656e69
   1000 
   1001     x86_cpuid(0, regs);
   1002     int vendorIsIntel = (regs[1] == VENDOR_INTEL_b &&
   1003                          regs[2] == VENDOR_INTEL_c &&
   1004                          regs[3] == VENDOR_INTEL_d);
   1005 
   1006     x86_cpuid(1, regs);
   1007     if ((regs[2] & (1 << 9)) != 0) {
   1008         g_cpuFeatures |= ANDROID_CPU_X86_FEATURE_SSSE3;
   1009     }
   1010     if ((regs[2] & (1 << 23)) != 0) {
   1011         g_cpuFeatures |= ANDROID_CPU_X86_FEATURE_POPCNT;
   1012     }
   1013     if (vendorIsIntel && (regs[2] & (1 << 22)) != 0) {
   1014         g_cpuFeatures |= ANDROID_CPU_X86_FEATURE_MOVBE;
   1015     }
   1016 #endif
   1017 
   1018     free(cpuinfo);
   1019 }
   1020 
   1021 
   1022 AndroidCpuFamily
   1023 android_getCpuFamily(void)
   1024 {
   1025     pthread_once(&g_once, android_cpuInit);
   1026     return g_cpuFamily;
   1027 }
   1028 
   1029 
   1030 uint64_t
   1031 android_getCpuFeatures(void)
   1032 {
   1033     pthread_once(&g_once, android_cpuInit);
   1034     return g_cpuFeatures;
   1035 }
   1036 
   1037 
   1038 int
   1039 android_getCpuCount(void)
   1040 {
   1041     pthread_once(&g_once, android_cpuInit);
   1042     return g_cpuCount;
   1043 }
   1044 
   1045 static void
   1046 android_cpuInitDummy(void)
   1047 {
   1048     g_inited = 1;
   1049 }
   1050 
   1051 int
   1052 android_setCpu(int cpu_count, uint64_t cpu_features)
   1053 {
   1054     /* Fail if the library was already initialized. */
   1055     if (g_inited)
   1056         return 0;
   1057 
   1058     android_cpuInitFamily();
   1059     g_cpuCount = (cpu_count <= 0 ? 1 : cpu_count);
   1060     g_cpuFeatures = cpu_features;
   1061     pthread_once(&g_once, android_cpuInitDummy);
   1062 
   1063     return 1;
   1064 }
   1065 
   1066 #ifdef __arm__
   1067 uint32_t
   1068 android_getCpuIdArm(void)
   1069 {
   1070     pthread_once(&g_once, android_cpuInit);
   1071     return g_cpuIdArm;
   1072 }
   1073 
   1074 int
   1075 android_setCpuArm(int cpu_count, uint64_t cpu_features, uint32_t cpu_id)
   1076 {
   1077     if (!android_setCpu(cpu_count, cpu_features))
   1078         return 0;
   1079 
   1080     g_cpuIdArm = cpu_id;
   1081     return 1;
   1082 }
   1083 #endif  /* __arm__ */
   1084 
   1085 /*
   1086  * Technical note: Making sense of ARM's FPU architecture versions.
   1087  *
   1088  * FPA was ARM's first attempt at an FPU architecture. There is no Android
   1089  * device that actually uses it since this technology was already obsolete
   1090  * when the project started. If you see references to FPA instructions
   1091  * somewhere, you can be sure that this doesn't apply to Android at all.
   1092  *
   1093  * FPA was followed by "VFP", soon renamed "VFPv1" due to the emergence of
   1094  * new versions / additions to it. ARM considers this obsolete right now,
   1095  * and no known Android device implements it either.
   1096  *
   1097  * VFPv2 added a few instructions to VFPv1, and is an *optional* extension
   1098  * supported by some ARMv5TE, ARMv6 and ARMv6T2 CPUs. Note that a device
   1099  * supporting the 'armeabi' ABI doesn't necessarily support these.
   1100  *
   1101  * VFPv3-D16 adds a few instructions on top of VFPv2 and is typically used
   1102  * on ARMv7-A CPUs which implement a FPU. Note that it is also mandated
   1103  * by the Android 'armeabi-v7a' ABI. The -D16 suffix in its name means
   1104  * that it provides 16 double-precision FPU registers (d0-d15) and 32
   1105  * single-precision ones (s0-s31) which happen to be mapped to the same
   1106  * register banks.
   1107  *
   1108  * VFPv3-D32 is the name of an extension to VFPv3-D16 that provides 16
   1109  * additional double precision registers (d16-d31). Note that there are
   1110  * still only 32 single precision registers.
   1111  *
   1112  * VFPv3xD is a *subset* of VFPv3-D16 that only provides single-precision
   1113  * registers. It is only used on ARMv7-M (i.e. on micro-controllers) which
   1114  * are not supported by Android. Note that it is not compatible with VFPv2.
   1115  *
   1116  * NOTE: The term 'VFPv3' usually designate either VFPv3-D16 or VFPv3-D32
   1117  *       depending on context. For example GCC uses it for VFPv3-D32, but
   1118  *       the Linux kernel code uses it for VFPv3-D16 (especially in
   1119  *       /proc/cpuinfo). Always try to use the full designation when
   1120  *       possible.
   1121  *
   1122  * NEON, a.k.a. "ARM Advanced SIMD" is an extension that provides
   1123  * instructions to perform parallel computations on vectors of 8, 16,
   1124  * 32, 64 and 128 bit quantities. NEON requires VFPv32-D32 since all
   1125  * NEON registers are also mapped to the same register banks.
   1126  *
   1127  * VFPv4-D16, adds a few instructions on top of VFPv3-D16 in order to
   1128  * perform fused multiply-accumulate on VFP registers, as well as
   1129  * half-precision (16-bit) conversion operations.
   1130  *
   1131  * VFPv4-D32 is VFPv4-D16 with 32, instead of 16, FPU double precision
   1132  * registers.
   1133  *
   1134  * VPFv4-NEON is VFPv4-D32 with NEON instructions. It also adds fused
   1135  * multiply-accumulate instructions that work on the NEON registers.
   1136  *
   1137  * NOTE: Similarly, "VFPv4" might either reference VFPv4-D16 or VFPv4-D32
   1138  *       depending on context.
   1139  *
   1140  * The following information was determined by scanning the binutils-2.22
   1141  * sources:
   1142  *
   1143  * Basic VFP instruction subsets:
   1144  *
   1145  * #define FPU_VFP_EXT_V1xD 0x08000000     // Base VFP instruction set.
   1146  * #define FPU_VFP_EXT_V1   0x04000000     // Double-precision insns.
   1147  * #define FPU_VFP_EXT_V2   0x02000000     // ARM10E VFPr1.
   1148  * #define FPU_VFP_EXT_V3xD 0x01000000     // VFPv3 single-precision.
   1149  * #define FPU_VFP_EXT_V3   0x00800000     // VFPv3 double-precision.
   1150  * #define FPU_NEON_EXT_V1  0x00400000     // Neon (SIMD) insns.
   1151  * #define FPU_VFP_EXT_D32  0x00200000     // Registers D16-D31.
   1152  * #define FPU_VFP_EXT_FP16 0x00100000     // Half-precision extensions.
   1153  * #define FPU_NEON_EXT_FMA 0x00080000     // Neon fused multiply-add
   1154  * #define FPU_VFP_EXT_FMA  0x00040000     // VFP fused multiply-add
   1155  *
   1156  * FPU types (excluding NEON)
   1157  *
   1158  * FPU_VFP_V1xD (EXT_V1xD)
   1159  *    |
   1160  *    +--------------------------+
   1161  *    |                          |
   1162  * FPU_VFP_V1 (+EXT_V1)       FPU_VFP_V3xD (+EXT_V2+EXT_V3xD)
   1163  *    |                          |
   1164  *    |                          |
   1165  * FPU_VFP_V2 (+EXT_V2)       FPU_VFP_V4_SP_D16 (+EXT_FP16+EXT_FMA)
   1166  *    |
   1167  * FPU_VFP_V3D16 (+EXT_Vx3D+EXT_V3)
   1168  *    |
   1169  *    +--------------------------+
   1170  *    |                          |
   1171  * FPU_VFP_V3 (+EXT_D32)     FPU_VFP_V4D16 (+EXT_FP16+EXT_FMA)
   1172  *    |                          |
   1173  *    |                      FPU_VFP_V4 (+EXT_D32)
   1174  *    |
   1175  * FPU_VFP_HARD (+EXT_FMA+NEON_EXT_FMA)
   1176  *
   1177  * VFP architectures:
   1178  *
   1179  * ARCH_VFP_V1xD  (EXT_V1xD)
   1180  *   |
   1181  *   +------------------+
   1182  *   |                  |
   1183  *   |             ARCH_VFP_V3xD (+EXT_V2+EXT_V3xD)
   1184  *   |                  |
   1185  *   |             ARCH_VFP_V3xD_FP16 (+EXT_FP16)
   1186  *   |                  |
   1187  *   |             ARCH_VFP_V4_SP_D16 (+EXT_FMA)
   1188  *   |
   1189  * ARCH_VFP_V1 (+EXT_V1)
   1190  *   |
   1191  * ARCH_VFP_V2 (+EXT_V2)
   1192  *   |
   1193  * ARCH_VFP_V3D16 (+EXT_V3xD+EXT_V3)
   1194  *   |
   1195  *   +-------------------+
   1196  *   |                   |
   1197  *   |         ARCH_VFP_V3D16_FP16  (+EXT_FP16)
   1198  *   |
   1199  *   +-------------------+
   1200  *   |                   |
   1201  *   |         ARCH_VFP_V4_D16 (+EXT_FP16+EXT_FMA)
   1202  *   |                   |
   1203  *   |         ARCH_VFP_V4 (+EXT_D32)
   1204  *   |                   |
   1205  *   |         ARCH_NEON_VFP_V4 (+EXT_NEON+EXT_NEON_FMA)
   1206  *   |
   1207  * ARCH_VFP_V3 (+EXT_D32)
   1208  *   |
   1209  *   +-------------------+
   1210  *   |                   |
   1211  *   |         ARCH_VFP_V3_FP16 (+EXT_FP16)
   1212  *   |
   1213  * ARCH_VFP_V3_PLUS_NEON_V1 (+EXT_NEON)
   1214  *   |
   1215  * ARCH_NEON_FP16 (+EXT_FP16)
   1216  *
   1217  * -fpu=<name> values and their correspondance with FPU architectures above:
   1218  *
   1219  *   {"vfp",               FPU_ARCH_VFP_V2},
   1220  *   {"vfp9",              FPU_ARCH_VFP_V2},
   1221  *   {"vfp3",              FPU_ARCH_VFP_V3}, // For backwards compatbility.
   1222  *   {"vfp10",             FPU_ARCH_VFP_V2},
   1223  *   {"vfp10-r0",          FPU_ARCH_VFP_V1},
   1224  *   {"vfpxd",             FPU_ARCH_VFP_V1xD},
   1225  *   {"vfpv2",             FPU_ARCH_VFP_V2},
   1226  *   {"vfpv3",             FPU_ARCH_VFP_V3},
   1227  *   {"vfpv3-fp16",        FPU_ARCH_VFP_V3_FP16},
   1228  *   {"vfpv3-d16",         FPU_ARCH_VFP_V3D16},
   1229  *   {"vfpv3-d16-fp16",    FPU_ARCH_VFP_V3D16_FP16},
   1230  *   {"vfpv3xd",           FPU_ARCH_VFP_V3xD},
   1231  *   {"vfpv3xd-fp16",      FPU_ARCH_VFP_V3xD_FP16},
   1232  *   {"neon",              FPU_ARCH_VFP_V3_PLUS_NEON_V1},
   1233  *   {"neon-fp16",         FPU_ARCH_NEON_FP16},
   1234  *   {"vfpv4",             FPU_ARCH_VFP_V4},
   1235  *   {"vfpv4-d16",         FPU_ARCH_VFP_V4D16},
   1236  *   {"fpv4-sp-d16",       FPU_ARCH_VFP_V4_SP_D16},
   1237  *   {"neon-vfpv4",        FPU_ARCH_NEON_VFP_V4},
   1238  *
   1239  *
   1240  * Simplified diagram that only includes FPUs supported by Android:
   1241  * Only ARCH_VFP_V3D16 is actually mandated by the armeabi-v7a ABI,
   1242  * all others are optional and must be probed at runtime.
   1243  *
   1244  * ARCH_VFP_V3D16 (EXT_V1xD+EXT_V1+EXT_V2+EXT_V3xD+EXT_V3)
   1245  *   |
   1246  *   +-------------------+
   1247  *   |                   |
   1248  *   |         ARCH_VFP_V3D16_FP16  (+EXT_FP16)
   1249  *   |
   1250  *   +-------------------+
   1251  *   |                   |
   1252  *   |         ARCH_VFP_V4_D16 (+EXT_FP16+EXT_FMA)
   1253  *   |                   |
   1254  *   |         ARCH_VFP_V4 (+EXT_D32)
   1255  *   |                   |
   1256  *   |         ARCH_NEON_VFP_V4 (+EXT_NEON+EXT_NEON_FMA)
   1257  *   |
   1258  * ARCH_VFP_V3 (+EXT_D32)
   1259  *   |
   1260  *   +-------------------+
   1261  *   |                   |
   1262  *   |         ARCH_VFP_V3_FP16 (+EXT_FP16)
   1263  *   |
   1264  * ARCH_VFP_V3_PLUS_NEON_V1 (+EXT_NEON)
   1265  *   |
   1266  * ARCH_NEON_FP16 (+EXT_FP16)
   1267  *
   1268  */
   1269 
   1270 #endif // defined(__le32__) || defined(__le64__)
   1271