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 #ifndef CPU_FEATURES_H 29 #define CPU_FEATURES_H 30 31 #include <sys/cdefs.h> 32 #include <stdint.h> 33 34 __BEGIN_DECLS 35 36 /* A list of valid values returned by android_getCpuFamily(). 37 * They describe the CPU Architecture of the current process. 38 */ 39 typedef enum { 40 ANDROID_CPU_FAMILY_UNKNOWN = 0, 41 ANDROID_CPU_FAMILY_ARM, 42 ANDROID_CPU_FAMILY_X86, 43 ANDROID_CPU_FAMILY_MIPS, 44 ANDROID_CPU_FAMILY_ARM64, 45 ANDROID_CPU_FAMILY_X86_64, 46 ANDROID_CPU_FAMILY_MIPS64, 47 48 ANDROID_CPU_FAMILY_MAX /* do not remove */ 49 50 } AndroidCpuFamily; 51 52 /* Return the CPU family of the current process. 53 * 54 * Note that this matches the bitness of the current process. I.e. when 55 * running a 32-bit binary on a 64-bit capable CPU, this will return the 56 * 32-bit CPU family value. 57 */ 58 extern AndroidCpuFamily android_getCpuFamily(void); 59 60 /* Return a bitmap describing a set of optional CPU features that are 61 * supported by the current device's CPU. The exact bit-flags returned 62 * depend on the value returned by android_getCpuFamily(). See the 63 * documentation for the ANDROID_CPU_*_FEATURE_* flags below for details. 64 * 65 * NOTE: This will return 0 for the following architectures that don't have 66 * optional features listed at the moment: 67 * 68 * ANDROID_CPU_FAMILY_MIPS 69 * ANDROID_CPU_FAMILY_ARM64 70 * ANDROID_CPU_FAMILY_X86_64 71 * ANDROID_CPU_FAMILY_MIPS64 72 */ 73 extern uint64_t android_getCpuFeatures(void); 74 75 /* The list of feature flags for ANDROID_CPU_FAMILY_ARM that can be 76 * recognized by the library (see note below for 64-bit ARM). Value details 77 * are: 78 * 79 * VFPv2: 80 * CPU supports the VFPv2 instruction set. Many, but not all, ARMv6 CPUs 81 * support these instructions. VFPv2 is a subset of VFPv3 so this will 82 * be set whenever VFPv3 is set too. 83 * 84 * ARMv7: 85 * CPU supports the ARMv7-A basic instruction set. 86 * This feature is mandated by the 'armeabi-v7a' ABI. 87 * 88 * VFPv3: 89 * CPU supports the VFPv3-D16 instruction set, providing hardware FPU 90 * support for single and double precision floating point registers. 91 * Note that only 16 FPU registers are available by default, unless 92 * the D32 bit is set too. This feature is also mandated by the 93 * 'armeabi-v7a' ABI. 94 * 95 * VFP_D32: 96 * CPU VFP optional extension that provides 32 FPU registers, 97 * instead of 16. Note that ARM mandates this feature is the 'NEON' 98 * feature is implemented by the CPU. 99 * 100 * NEON: 101 * CPU FPU supports "ARM Advanced SIMD" instructions, also known as 102 * NEON. Note that this mandates the VFP_D32 feature as well, per the 103 * ARM Architecture specification. 104 * 105 * VFP_FP16: 106 * Half-width floating precision VFP extension. If set, the CPU 107 * supports instructions to perform floating-point operations on 108 * 16-bit registers. This is part of the VFPv4 specification, but 109 * not mandated by any Android ABI. 110 * 111 * VFP_FMA: 112 * Fused multiply-accumulate VFP instructions extension. Also part of 113 * the VFPv4 specification, but not mandated by any Android ABI. 114 * 115 * NEON_FMA: 116 * Fused multiply-accumulate NEON instructions extension. Optional 117 * extension from the VFPv4 specification, but not mandated by any 118 * Android ABI. 119 * 120 * IDIV_ARM: 121 * Integer division available in ARM mode. Only available 122 * on recent CPUs (e.g. Cortex-A15). 123 * 124 * IDIV_THUMB2: 125 * Integer division available in Thumb-2 mode. Only available 126 * on recent CPUs (e.g. Cortex-A15). 127 * 128 * iWMMXt: 129 * Optional extension that adds MMX registers and operations to an 130 * ARM CPU. This is only available on a few XScale-based CPU designs 131 * sold by Marvell. Pretty rare in practice. 132 * 133 * If you want to tell the compiler to generate code that targets one of 134 * the feature set above, you should probably use one of the following 135 * flags (for more details, see technical note at the end of this file): 136 * 137 * -mfpu=vfp 138 * -mfpu=vfpv2 139 * These are equivalent and tell GCC to use VFPv2 instructions for 140 * floating-point operations. Use this if you want your code to 141 * run on *some* ARMv6 devices, and any ARMv7-A device supported 142 * by Android. 143 * 144 * Generated code requires VFPv2 feature. 145 * 146 * -mfpu=vfpv3-d16 147 * Tell GCC to use VFPv3 instructions (using only 16 FPU registers). 148 * This should be generic code that runs on any CPU that supports the 149 * 'armeabi-v7a' Android ABI. Note that no ARMv6 CPU supports this. 150 * 151 * Generated code requires VFPv3 feature. 152 * 153 * -mfpu=vfpv3 154 * Tell GCC to use VFPv3 instructions with 32 FPU registers. 155 * Generated code requires VFPv3|VFP_D32 features. 156 * 157 * -mfpu=neon 158 * Tell GCC to use VFPv3 instructions with 32 FPU registers, and 159 * also support NEON intrinsics (see <arm_neon.h>). 160 * Generated code requires VFPv3|VFP_D32|NEON features. 161 * 162 * -mfpu=vfpv4-d16 163 * Generated code requires VFPv3|VFP_FP16|VFP_FMA features. 164 * 165 * -mfpu=vfpv4 166 * Generated code requires VFPv3|VFP_FP16|VFP_FMA|VFP_D32 features. 167 * 168 * -mfpu=neon-vfpv4 169 * Generated code requires VFPv3|VFP_FP16|VFP_FMA|VFP_D32|NEON|NEON_FMA 170 * features. 171 * 172 * -mcpu=cortex-a7 173 * -mcpu=cortex-a15 174 * Generated code requires VFPv3|VFP_FP16|VFP_FMA|VFP_D32| 175 * NEON|NEON_FMA|IDIV_ARM|IDIV_THUMB2 176 * This flag implies -mfpu=neon-vfpv4. 177 * 178 * -mcpu=iwmmxt 179 * Allows the use of iWMMXt instrinsics with GCC. 180 * 181 * IMPORTANT NOTE: These flags should only be tested when 182 * android_getCpuFamily() returns ANDROID_CPU_FAMILY_ARM, i.e. this is a 183 * 32-bit process. 184 * 185 * When running a 64-bit ARM process on an ARMv8 CPU, 186 * android_getCpuFeatures() will return a different set of bitflags 187 * (currently always 0). 188 */ 189 enum { 190 ANDROID_CPU_ARM_FEATURE_ARMv7 = (1 << 0), 191 ANDROID_CPU_ARM_FEATURE_VFPv3 = (1 << 1), 192 ANDROID_CPU_ARM_FEATURE_NEON = (1 << 2), 193 ANDROID_CPU_ARM_FEATURE_LDREX_STREX = (1 << 3), 194 ANDROID_CPU_ARM_FEATURE_VFPv2 = (1 << 4), 195 ANDROID_CPU_ARM_FEATURE_VFP_D32 = (1 << 5), 196 ANDROID_CPU_ARM_FEATURE_VFP_FP16 = (1 << 6), 197 ANDROID_CPU_ARM_FEATURE_VFP_FMA = (1 << 7), 198 ANDROID_CPU_ARM_FEATURE_NEON_FMA = (1 << 8), 199 ANDROID_CPU_ARM_FEATURE_IDIV_ARM = (1 << 9), 200 ANDROID_CPU_ARM_FEATURE_IDIV_THUMB2 = (1 << 10), 201 ANDROID_CPU_ARM_FEATURE_iWMMXt = (1 << 11), 202 }; 203 204 /* The bit flags corresponding to the output of android_getCpuFeatures() 205 * when android_getCpuFamily() returns ANDROID_CPU_FAMILY_X86. 206 */ 207 enum { 208 ANDROID_CPU_X86_FEATURE_SSSE3 = (1 << 0), 209 ANDROID_CPU_X86_FEATURE_POPCNT = (1 << 1), 210 ANDROID_CPU_X86_FEATURE_MOVBE = (1 << 2), 211 }; 212 213 /* Return the number of CPU cores detected on this device. */ 214 extern int android_getCpuCount(void); 215 216 /* The following is used to force the CPU count and features 217 * mask in sandboxed processes. Under 4.1 and higher, these processes 218 * cannot access /proc, which is the only way to get information from 219 * the kernel about the current hardware (at least on ARM). 220 * 221 * It _must_ be called only once, and before any android_getCpuXXX 222 * function, any other case will fail. 223 * 224 * This function return 1 on success, and 0 on failure. 225 */ 226 extern int android_setCpu(int cpu_count, 227 uint64_t cpu_features); 228 229 #ifdef __arm__ 230 /* Retrieve the ARM 32-bit CPUID value from the kernel. 231 * Note that this cannot work on sandboxed processes under 4.1 and 232 * higher, unless you called android_setCpuArm() before. 233 */ 234 extern uint32_t android_getCpuIdArm(void); 235 236 /* An ARM-specific variant of android_setCpu() that also allows you 237 * to set the ARM CPUID field. 238 */ 239 extern int android_setCpuArm(int cpu_count, 240 uint64_t cpu_features, 241 uint32_t cpu_id); 242 #endif 243 244 __END_DECLS 245 246 #endif /* CPU_FEATURES_H */ 247
