1 /* Copyright (c) 2014, Google Inc.
2 *
3 * Permission to use, copy, modify, and/or distribute this software for any
4 * purpose with or without fee is hereby granted, provided that the above
5 * copyright notice and this permission notice appear in all copies.
6 *
7 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
8 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
9 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
10 * SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
11 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION
12 * OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
13 * CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. */
14
15 #include <openssl/cpu.h>
16
17 #if (defined(OPENSSL_ARM) || defined(OPENSSL_AARCH64)) && \
18 !defined(OPENSSL_STATIC_ARMCAP)
19
20 #include <inttypes.h>
21 #include <string.h>
22
23 #include <setjmp.h>
24 #include <signal.h>
25
26 #include <openssl/arm_arch.h>
27
28
29 /* We can't include <sys/auxv.h> because the Android SDK version against which
30 * Chromium builds is too old to have it. Instead we define all the constants
31 * that we need and have a weak pointer to getauxval. */
32
33 unsigned long getauxval(unsigned long type) __attribute__((weak));
34
35 extern uint32_t OPENSSL_armcap_P;
36
CRYPTO_is_NEON_capable_at_runtime(void)37 char CRYPTO_is_NEON_capable_at_runtime(void) {
38 return (OPENSSL_armcap_P & ARMV7_NEON) != 0;
39 }
40
41 static char g_set_neon_called = 0;
42
CRYPTO_set_NEON_capable(char neon_capable)43 void CRYPTO_set_NEON_capable(char neon_capable) {
44 g_set_neon_called = 1;
45
46 if (neon_capable) {
47 OPENSSL_armcap_P |= ARMV7_NEON;
48 } else {
49 OPENSSL_armcap_P &= ~ARMV7_NEON;
50 }
51 }
52
CRYPTO_is_NEON_functional(void)53 char CRYPTO_is_NEON_functional(void) {
54 static const uint32_t kWantFlags = ARMV7_NEON | ARMV7_NEON_FUNCTIONAL;
55 return (OPENSSL_armcap_P & kWantFlags) == kWantFlags;
56 }
57
CRYPTO_set_NEON_functional(char neon_functional)58 void CRYPTO_set_NEON_functional(char neon_functional) {
59 if (neon_functional) {
60 OPENSSL_armcap_P |= ARMV7_NEON_FUNCTIONAL;
61 } else {
62 OPENSSL_armcap_P &= ~ARMV7_NEON_FUNCTIONAL;
63 }
64 }
65
CRYPTO_is_ARMv8_AES_capable(void)66 int CRYPTO_is_ARMv8_AES_capable(void) {
67 return (OPENSSL_armcap_P & ARMV8_AES) != 0;
68 }
69
CRYPTO_is_ARMv8_PMULL_capable(void)70 int CRYPTO_is_ARMv8_PMULL_capable(void) {
71 return (OPENSSL_armcap_P & ARMV8_PMULL) != 0;
72 }
73
74 #if !defined(OPENSSL_NO_ASM) && defined(OPENSSL_ARM)
75
76 static sigjmp_buf sigill_jmp;
77
sigill_handler(int signal)78 static void sigill_handler(int signal) {
79 siglongjmp(sigill_jmp, signal);
80 }
81
82 void CRYPTO_arm_neon_probe(void);
83
84 // probe_for_NEON returns 1 if a NEON instruction runs successfully. Because
85 // getauxval doesn't exist on Android until Jelly Bean, supporting NEON on
86 // older devices requires this.
probe_for_NEON(void)87 static int probe_for_NEON(void) {
88 int supported = 0;
89
90 sigset_t sigmask;
91 sigfillset(&sigmask);
92 sigdelset(&sigmask, SIGILL);
93 sigdelset(&sigmask, SIGTRAP);
94 sigdelset(&sigmask, SIGFPE);
95 sigdelset(&sigmask, SIGBUS);
96 sigdelset(&sigmask, SIGSEGV);
97
98 struct sigaction sigill_original_action, sigill_action;
99 memset(&sigill_action, 0, sizeof(sigill_action));
100 sigill_action.sa_handler = sigill_handler;
101 sigill_action.sa_mask = sigmask;
102
103 sigset_t original_sigmask;
104 sigprocmask(SIG_SETMASK, &sigmask, &original_sigmask);
105
106 if (sigsetjmp(sigill_jmp, 1 /* save signals */) == 0) {
107 sigaction(SIGILL, &sigill_action, &sigill_original_action);
108
109 // This function cannot be inline asm because GCC will refuse to compile
110 // inline NEON instructions unless building with -mfpu=neon, which would
111 // defeat the point of probing for support at runtime.
112 CRYPTO_arm_neon_probe();
113 supported = 1;
114 }
115 // Note that Android up to and including Lollipop doesn't restore the signal
116 // mask correctly after returning from a sigsetjmp. So that would need to be
117 // set again here if more probes were added.
118 // See https://android-review.googlesource.com/#/c/127624/
119
120 sigaction(SIGILL, &sigill_original_action, NULL);
121 sigprocmask(SIG_SETMASK, &original_sigmask, NULL);
122
123 return supported;
124 }
125
126 #else
127
probe_for_NEON(void)128 static int probe_for_NEON(void) {
129 return 0;
130 }
131
132 #endif /* !OPENSSL_NO_ASM && OPENSSL_ARM */
133
OPENSSL_cpuid_setup(void)134 void OPENSSL_cpuid_setup(void) {
135 if (getauxval == NULL) {
136 // On ARM, but not AArch64, try a NEON instruction and see whether it works
137 // in order to probe for NEON support.
138 //
139 // Note that |CRYPTO_is_NEON_capable| can be true even if
140 // |CRYPTO_set_NEON_capable| has never been called if the code was compiled
141 // with NEON support enabled (e.g. -mfpu=neon).
142 if (!g_set_neon_called && !CRYPTO_is_NEON_capable() && probe_for_NEON()) {
143 OPENSSL_armcap_P |= ARMV7_NEON;
144 }
145 return;
146 }
147
148 static const unsigned long AT_HWCAP = 16;
149 unsigned long hwcap = getauxval(AT_HWCAP);
150
151 #if defined(OPENSSL_ARM)
152 static const unsigned long kNEON = 1 << 12;
153 if ((hwcap & kNEON) == 0) {
154 return;
155 }
156
157 /* In 32-bit mode, the ARMv8 feature bits are in a different aux vector
158 * value. */
159 static const unsigned long AT_HWCAP2 = 26;
160 hwcap = getauxval(AT_HWCAP2);
161
162 /* See /usr/include/asm/hwcap.h on an ARM installation for the source of
163 * these values. */
164 static const unsigned long kAES = 1 << 0;
165 static const unsigned long kPMULL = 1 << 1;
166 static const unsigned long kSHA1 = 1 << 2;
167 static const unsigned long kSHA256 = 1 << 3;
168 #elif defined(OPENSSL_AARCH64)
169 /* See /usr/include/asm/hwcap.h on an aarch64 installation for the source of
170 * these values. */
171 static const unsigned long kNEON = 1 << 1;
172 static const unsigned long kAES = 1 << 3;
173 static const unsigned long kPMULL = 1 << 4;
174 static const unsigned long kSHA1 = 1 << 5;
175 static const unsigned long kSHA256 = 1 << 6;
176
177 if ((hwcap & kNEON) == 0) {
178 return;
179 }
180 #endif
181
182 OPENSSL_armcap_P |= ARMV7_NEON;
183
184 if (hwcap & kAES) {
185 OPENSSL_armcap_P |= ARMV8_AES;
186 }
187 if (hwcap & kPMULL) {
188 OPENSSL_armcap_P |= ARMV8_PMULL;
189 }
190 if (hwcap & kSHA1) {
191 OPENSSL_armcap_P |= ARMV8_SHA1;
192 }
193 if (hwcap & kSHA256) {
194 OPENSSL_armcap_P |= ARMV8_SHA256;
195 }
196 }
197
198 #endif /* (defined(OPENSSL_ARM) || defined(OPENSSL_AARCH64)) &&
199 !defined(OPENSSL_STATIC_ARMCAP) */
200