Bug 779687 - Add detection for ARMv7 CPUs. r=dougt

toolkit/components/telemetry/TelemetryPing.js

@@ -369,20 +369,20 @@ TelemetryPing.prototype = {
     let fields = ["cpucount", "memsize", "arch", "version", "device", "manufacturer", "hardware",
                   "hasMMX", "hasSSE", "hasSSE2", "hasSSE3",
                   "hasSSSE3", "hasSSE4A", "hasSSE4_1", "hasSSE4_2",
-                  "hasEDSP", "hasARMv6", "hasNEON"];
+                  "hasEDSP", "hasARMv6", "hasARMv7", "hasNEON"];
     for each (let field in fields) {
       let value;
       try {
         value = sysInfo.getProperty(field);
       } catch (e) {
-        continue
+        continue;
       }
       if (field == "memsize") {
         // Send RAM size in megabytes. Rounding because sysinfo doesn't
         // always provide RAM in multiples of 1024.
-        value = Math.round(value / 1024 / 1024)
+        value = Math.round(value / 1024 / 1024);
       }
-      ret[field] = value
+      ret[field] = value;
     }
 
     // gfxInfo fields are not always available, get what we can.

xpcom/base/nsSystemInfo.cpp

@@ -57,6 +57,7 @@ static const struct PropItems {
     // ARM-specific bits.
     { "hasEDSP", mozilla::supports_edsp },
     { "hasARMv6", mozilla::supports_armv6 },
+    { "hasARMv7", mozilla::supports_armv7 },
     { "hasNEON", mozilla::supports_neon }
 };
 

xpcom/glue/arm.cpp

@@ -60,6 +60,29 @@ check_armv6(void)
 }
 #    endif // !MOZILLA_PRESUME_ARMV6
 
+#    if !defined(MOZILLA_PRESUME_ARMV7)
+static bool
+check_armv7(void)
+{
+#      if defined(MOZILLA_MAY_SUPPORT_ARMV7)
+  __try
+  {
+    // ARMv7 DMB (Data Memory Barrier) for stores (DMB.ST)
+    // The Data Memory Barrier existed before ARMv7 as a
+    // cp15 operation, but ARMv7 introduced a dedicated
+    // instruction, DMB.
+    emit(0xF57FF05E);
+    return true;
+  }
+  __except(GetExceptionCode()==EXCEPTION_ILLEGAL_INSTRUCTION)
+  {
+    //Ignore exception.
+  }
+#      endif
+  return false;
+}
+#    endif // !MOZILLA_PRESUME_ARMV7
+
 #    if !defined(MOZILLA_PRESUME_NEON)
 static bool
 check_neon(void)
@@ -88,7 +111,8 @@ check_neon(void)
 enum{
   MOZILLA_HAS_EDSP_FLAG=1,
   MOZILLA_HAS_ARMV6_FLAG=2,
-  MOZILLA_HAS_NEON_FLAG=4
+  MOZILLA_HAS_ARMV7_FLAG=4,
+  MOZILLA_HAS_NEON_FLAG=8
 };
 
 static unsigned
@@ -96,6 +120,7 @@ get_arm_cpu_flags(void)
 {
   unsigned  flags;
   FILE     *fin;
+  bool      armv6_processor = false;
   flags = 0;
   /*Reading /proc/self/auxv would be easier, but that doesn't work reliably on
     Android. This also means that detection will fail in Scratchbox, which is
@@ -126,10 +151,32 @@ get_arm_cpu_flags(void)
         version = atoi(buf + 17);
         if (version >= 6)
           flags |= MOZILLA_HAS_ARMV6_FLAG;
+        if (version >= 7)
+          flags |= MOZILLA_HAS_ARMV7_FLAG;
+      }
+      /* media/webrtc/trunk/src/system_wrappers/source/cpu_features_arm.c
+       * Unfortunately, it seems that certain ARMv6-based CPUs
+       * report an incorrect architecture number of 7!
+       *
+       * We try to correct this by looking at the 'elf_format'
+       * field reported by the 'Processor' field, which is of the
+       * form of "(v7l)" for an ARMv7-based CPU, and "(v6l)" for
+       * an ARMv6-one.
+       */
+      if (memcmp(buf, "Processor\t:", 11) == 0) {
+          if (strstr(buf, "(v6l)") != 0) {
+              armv6_processor = true;
+          }
       }
     }
     fclose(fin);
   }
+  if (armv6_processor) {
+      // ARMv6 pretending to be ARMv7? clear flag
+      if (flags & MOZILLA_HAS_ARMV7_FLAG) {
+          flags &= ~MOZILLA_HAS_ARMV7_FLAG;
+      }
+  }
   return flags;
 }
 
@@ -152,6 +199,14 @@ check_armv6(void)
 }
 #    endif
 
+#    if !defined(MOZILLA_PRESUME_ARMV7)
+static bool
+check_armv7(void)
+{
+  return (arm_cpu_flags & MOZILLA_HAS_ARMV7_FLAG) != 0;
+}
+#    endif
+
 #    if !defined(MOZILLA_PRESUME_NEON)
 static bool
 check_neon(void)
@@ -172,6 +227,9 @@ namespace mozilla {
 #  if !defined(MOZILLA_PRESUME_ARMV6)
     bool armv6_enabled = check_armv6();
 #  endif
+#  if !defined(MOZILLA_PRESUME_ARMV7)
+    bool armv7_enabled = check_armv7();
+#  endif
 #  if !defined(MOZILLA_PRESUME_NEON)
     bool neon_enabled = check_neon();
 #  endif

xpcom/glue/arm.h

@@ -71,6 +71,13 @@
 #    if defined(HAVE_ARM_NEON)
 #      define MOZILLA_MAY_SUPPORT_NEON 1
 #    endif
+#  endif
+
+  // ARMv7 support was merged in gcc 4.3.
+#  if __GNUC__> 4 || (__GNUC__ == 4 && __GNUC_MINOR__ >= 3)
+#    if defined(HAVE_ARM_SIMD)
+#      define MOZILLA_MAY_SUPPORT_ARMV7 1
+#    endif
 #  endif
 
   // When using -mfpu=neon, gcc generates neon instructions.
@@ -95,6 +102,7 @@
 #  define MOZILLA_MAY_SUPPORT_EDSP 1
 #  if defined(HAVE_ARM_SIMD)
 #    define MOZILLA_MAY_SUPPORT_ARMV6 1
+#    define MOZILLA_MAY_SUPPORT_ARMV7 1
 #  endif
 #  if defined(HAVE_ARM_NEON)
 #    define MOZILLA_MAY_SUPPORT_NEON 1
@@ -112,6 +120,9 @@ namespace mozilla {
 #if !defined(MOZILLA_PRESUME_ARMV6)
     extern bool NS_COM_GLUE armv6_enabled;
 #endif
+#if !defined(MOZILLA_PRESUME_ARMV7)
+    extern bool NS_COM_GLUE armv7_enabled;
+#endif
 #if !defined(MOZILLA_PRESUME_NEON)
     extern bool NS_COM_GLUE neon_enabled;
 #endif
@@ -138,6 +149,16 @@ namespace mozilla {
   inline bool supports_armv6() { return false; }
 #endif
 
+#if defined(MOZILLA_PRESUME_ARMV7)
+#  define MOZILLA_MAY_SUPPORT_ARMV7 1
+  inline bool supports_armv7() { return true; }
+#elif defined(MOZILLA_MAY_SUPPORT_ARMV7) \
+   && defined(MOZILLA_ARM_HAVE_CPUID_DETECTION)
+  inline bool supports_armv7() { return arm_private::armv7_enabled; }
+#else
+  inline bool supports_armv7() { return false; }
+#endif
+
 #if defined(MOZILLA_PRESUME_NEON)
 #  define MOZILLA_MAY_SUPPORT_NEON 1
   inline bool supports_neon() { return true; }