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
19 #include <inttypes.h>
20 #include <string.h>
21
22 #if !defined(OPENSSL_TRUSTY)
23 #include <setjmp.h>
24 #include <signal.h>
25 #endif
26
27 #include "arm_arch.h"
28
29
30 /* We can't include <sys/auxv.h> because the Android SDK version against which
31 * Chromium builds is too old to have it. Instead we define all the constants
32 * that we need and have a weak pointer to getauxval. */
33
34 unsigned long getauxval(unsigned long type) __attribute__((weak));
35
CRYPTO_is_NEON_capable(void)36 char CRYPTO_is_NEON_capable(void) {
37 return (OPENSSL_armcap_P & ARMV7_NEON) != 0;
38 }
39
40 static char g_set_neon_called = 0;
41
CRYPTO_set_NEON_capable(char neon_capable)42 void CRYPTO_set_NEON_capable(char neon_capable) {
43 g_set_neon_called = 1;
44
45 if (neon_capable) {
46 OPENSSL_armcap_P |= ARMV7_NEON;
47 } else {
48 OPENSSL_armcap_P &= ~ARMV7_NEON;
49 }
50 }
51
CRYPTO_is_NEON_functional(void)52 char CRYPTO_is_NEON_functional(void) {
53 static const uint32_t kWantFlags = ARMV7_NEON | ARMV7_NEON_FUNCTIONAL;
54 return (OPENSSL_armcap_P & kWantFlags) == kWantFlags;
55 }
56
CRYPTO_set_NEON_functional(char neon_functional)57 void CRYPTO_set_NEON_functional(char neon_functional) {
58 if (neon_functional) {
59 OPENSSL_armcap_P |= ARMV7_NEON_FUNCTIONAL;
60 } else {
61 OPENSSL_armcap_P &= ~ARMV7_NEON_FUNCTIONAL;
62 }
63 }
64
65 #if !defined(OPENSSL_NO_ASM) && defined(OPENSSL_ARM) && !defined(OPENSSL_TRUSTY)
66
67 static sigjmp_buf sigill_jmp;
68
sigill_handler(int signal)69 static void sigill_handler(int signal) {
70 siglongjmp(sigill_jmp, signal);
71 }
72
73 void CRYPTO_arm_neon_probe();
74
75 // probe_for_NEON returns 1 if a NEON instruction runs successfully. Because
76 // getauxval doesn't exist on Android until Jelly Bean, supporting NEON on
77 // older devices requires this.
probe_for_NEON()78 static int probe_for_NEON() {
79 int supported = 0;
80
81 sigset_t sigmask;
82 sigfillset(&sigmask);
83 sigdelset(&sigmask, SIGILL);
84 sigdelset(&sigmask, SIGTRAP);
85 sigdelset(&sigmask, SIGFPE);
86 sigdelset(&sigmask, SIGBUS);
87 sigdelset(&sigmask, SIGSEGV);
88
89 struct sigaction sigill_original_action, sigill_action;
90 memset(&sigill_action, 0, sizeof(sigill_action));
91 sigill_action.sa_handler = sigill_handler;
92 sigill_action.sa_mask = sigmask;
93
94 sigset_t original_sigmask;
95 sigprocmask(SIG_SETMASK, &sigmask, &original_sigmask);
96
97 if (sigsetjmp(sigill_jmp, 1 /* save signals */) == 0) {
98 sigaction(SIGILL, &sigill_action, &sigill_original_action);
99
100 // This function cannot be inline asm because GCC will refuse to compile
101 // inline NEON instructions unless building with -mfpu=neon, which would
102 // defeat the point of probing for support at runtime.
103 CRYPTO_arm_neon_probe();
104 supported = 1;
105 }
106 // Note that Android up to and including Lollipop doesn't restore the signal
107 // mask correctly after returning from a sigsetjmp. So that would need to be
108 // set again here if more probes were added.
109 // See https://android-review.googlesource.com/#/c/127624/
110
111 sigaction(SIGILL, &sigill_original_action, NULL);
112 sigprocmask(SIG_SETMASK, &original_sigmask, NULL);
113
114 return supported;
115 }
116
117 #else
118
probe_for_NEON(void)119 static int probe_for_NEON(void) {
120 return 0;
121 }
122
123 #endif /* !OPENSSL_NO_ASM && OPENSSL_ARM && !OPENSSL_TRUSTY */
124
OPENSSL_cpuid_setup(void)125 void OPENSSL_cpuid_setup(void) {
126 if (getauxval == NULL) {
127 // On ARM, but not AArch64, try a NEON instruction and see whether it works
128 // in order to probe for NEON support.
129 //
130 // Note that |CRYPTO_is_NEON_capable| can be true even if
131 // |CRYPTO_set_NEON_capable| has never been called if the code was compiled
132 // with NEON support enabled (e.g. -mfpu=neon).
133 if (!g_set_neon_called && !CRYPTO_is_NEON_capable() && probe_for_NEON()) {
134 OPENSSL_armcap_P |= ARMV7_NEON;
135 }
136 return;
137 }
138
139 static const unsigned long AT_HWCAP = 16;
140 unsigned long hwcap = getauxval(AT_HWCAP);
141
142 #if defined(OPENSSL_ARM)
143 static const unsigned long kNEON = 1 << 12;
144 if ((hwcap & kNEON) == 0) {
145 return;
146 }
147
148 /* In 32-bit mode, the ARMv8 feature bits are in a different aux vector
149 * value. */
150 static const unsigned long AT_HWCAP2 = 26;
151 hwcap = getauxval(AT_HWCAP2);
152
153 /* See /usr/include/asm/hwcap.h on an ARM installation for the source of
154 * these values. */
155 static const unsigned long kAES = 1 << 0;
156 static const unsigned long kPMULL = 1 << 1;
157 static const unsigned long kSHA1 = 1 << 2;
158 static const unsigned long kSHA256 = 1 << 3;
159 #elif defined(OPENSSL_AARCH64)
160 /* See /usr/include/asm/hwcap.h on an aarch64 installation for the source of
161 * these values. */
162 static const unsigned long kNEON = 1 << 1;
163 static const unsigned long kAES = 1 << 3;
164 static const unsigned long kPMULL = 1 << 4;
165 static const unsigned long kSHA1 = 1 << 5;
166 static const unsigned long kSHA256 = 1 << 6;
167
168 if ((hwcap & kNEON) == 0) {
169 return;
170 }
171 #endif
172
173 OPENSSL_armcap_P |= ARMV7_NEON;
174
175 if (hwcap & kAES) {
176 OPENSSL_armcap_P |= ARMV8_AES;
177 }
178 if (hwcap & kPMULL) {
179 OPENSSL_armcap_P |= ARMV8_PMULL;
180 }
181 if (hwcap & kSHA1) {
182 OPENSSL_armcap_P |= ARMV8_SHA1;
183 }
184 if (hwcap & kSHA256) {
185 OPENSSL_armcap_P |= ARMV8_SHA256;
186 }
187 }
188
189 #endif /* defined(OPENSSL_ARM) || defined(OPENSSL_AARCH64) */
190