2 * mach-support-arm.c: mach support for ARM
5 * Geoff Norton (gnorton@novell.com)
6 * Rodrigo Kumpera (kumpera@gmail.com)
8 * (C) 2010 Novell, Inc.
9 * (C) 2011 Xamarin, Inc.
18 #include "utils/mono-sigcontext.h"
19 #include "utils/mono-compiler.h"
20 #include "mach-support.h"
22 /* _mcontext.h now defines __darwin_mcontext32, not __darwin_mcontext, starting with Xcode 5.1 */
23 #ifdef _STRUCT_MCONTEXT32
24 #define __darwin_mcontext __darwin_mcontext32
27 /* Known offsets used for TLS storage*/
30 static const int known_tls_offsets[] = {
31 0x48, /*Found on iOS 6 */
36 #define TLS_PROBE_COUNT (sizeof (known_tls_offsets) / sizeof (int))
38 /* This is 2 slots less than the known low */
39 #define TLS_PROBE_LOW_WATERMARK 0x40
40 /* This is 24 slots above the know high, which is the same diff as the knowns high-low*/
41 #define TLS_PROBE_HIGH_WATERMARK 0x108
43 static int tls_vector_offset;
46 mono_mach_arch_get_ip (thread_state_t state)
48 /* Can't use unified_thread_state on !ARM64 since this has to compile on armv6 too */
49 arm_unified_thread_state_t *arch_state = (arm_unified_thread_state_t *) state;
51 return (void *) arch_state->ts_64.__pc;
55 mono_mach_arch_get_sp (thread_state_t state)
57 arm_unified_thread_state_t *arch_state = (arm_unified_thread_state_t *) state;
59 return (void *) arch_state->ts_64.__sp;
63 mono_mach_arch_get_mcontext_size ()
65 return sizeof (struct __darwin_mcontext64);
69 mono_mach_arch_thread_state_to_mcontext (thread_state_t state, void *context)
71 arm_unified_thread_state_t *arch_state = (arm_unified_thread_state_t *) state;
72 struct __darwin_mcontext64 *ctx = (struct __darwin_mcontext64 *) context;
74 ctx->__ss = arch_state->ts_64;
78 mono_mach_arch_mcontext_to_thread_state (void *context, thread_state_t state)
80 arm_unified_thread_state_t *arch_state = (arm_unified_thread_state_t *) state;
81 struct __darwin_mcontext64 *ctx = (struct __darwin_mcontext64 *) context;
83 arch_state->ts_64 = ctx->__ss;
87 mono_mach_arch_thread_state_to_mono_context (thread_state_t state, MonoContext *context)
90 arm_unified_thread_state_t *arch_state = (arm_unified_thread_state_t *) state;
91 for (i = 0; i < 29; ++i)
92 context->regs [i] = arch_state->ts_64.__x [i];
94 context->regs [ARMREG_R29] = arch_state->ts_64.__fp;
95 context->regs [ARMREG_R30] = arch_state->ts_64.__lr;
96 context->regs [ARMREG_SP] = arch_state->ts_64.__sp;
97 context->pc = arch_state->ts_64.__pc;
101 mono_mach_arch_get_thread_state_size ()
103 return sizeof (arm_unified_thread_state_t);
107 mono_mach_arch_get_thread_state (thread_port_t thread, thread_state_t state, mach_msg_type_number_t *count)
109 arm_unified_thread_state_t *arch_state = (arm_unified_thread_state_t *) state;
112 *count = ARM_UNIFIED_THREAD_STATE_COUNT;
114 ret = thread_get_state (thread, ARM_UNIFIED_THREAD_STATE, (thread_state_t) arch_state, count);
119 mono_mach_arch_set_thread_state (thread_port_t thread, thread_state_t state, mach_msg_type_number_t count)
121 return thread_set_state (thread, ARM_UNIFIED_THREAD_STATE, state, count);
125 mono_mach_get_tls_address_from_thread (pthread_t thread, pthread_key_t key)
127 /* Mach stores TLS values in a hidden array inside the pthread_t structure
128 * They are keyed off a giant array from a known offset into the pointer. This value
129 * is baked into their pthread_getspecific implementation
131 intptr_t *p = (intptr_t *) thread;
132 intptr_t **tsd = (intptr_t **) ((char*)p + tls_vector_offset);
133 g_assert (tls_vector_offset != -1);
135 return (void *) &tsd [key];
139 mono_mach_arch_get_tls_value_from_thread (pthread_t thread, guint32 key)
141 return *(void**)mono_mach_get_tls_address_from_thread (thread, key);
145 mono_mach_init (pthread_key_t key)
148 void *old_value = pthread_getspecific (key);
149 void *canary = (void*)0xDEADBEEFu;
151 pthread_key_create (&key, NULL);
152 g_assert (old_value != canary);
154 pthread_setspecific (key, canary);
156 /*First we probe for cats*/
157 for (i = 0; i < TLS_PROBE_COUNT; ++i) {
158 tls_vector_offset = known_tls_offsets [i];
159 if (mono_mach_arch_get_tls_value_from_thread (pthread_self (), key) == canary)
163 /*Fallback to scanning a large range of offsets*/
164 for (i = TLS_PROBE_LOW_WATERMARK; i <= TLS_PROBE_HIGH_WATERMARK; i += 4) {
165 tls_vector_offset = i;
166 if (mono_mach_arch_get_tls_value_from_thread (pthread_self (), key) == canary) {
167 g_warning ("Found new TLS offset at %d", i);
172 tls_vector_offset = -1;
173 g_warning ("could not discover the mach TLS offset");
175 pthread_setspecific (key, old_value);