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_thread_state_t *arch_state = (arm_thread_state_t *) state;
51 return (void *) arch_state->__pc;
55 mono_mach_arch_get_sp (thread_state_t state)
57 arm_thread_state_t *arch_state = (arm_thread_state_t *) state;
59 return (void *) arch_state->__sp;
63 mono_mach_arch_get_mcontext_size ()
65 return sizeof (struct __darwin_mcontext);
69 mono_mach_arch_thread_state_to_mcontext (thread_state_t state, void *context)
71 arm_thread_state_t *arch_state = (arm_thread_state_t *) state;
72 struct __darwin_mcontext *ctx = (struct __darwin_mcontext *) context;
74 ctx->__ss = *arch_state;
78 mono_mach_arch_mcontext_to_thread_state (void *context, thread_state_t state)
80 arm_thread_state_t *arch_state = (arm_thread_state_t *) state;
81 struct __darwin_mcontext *ctx = (struct __darwin_mcontext *) context;
83 *arch_state = ctx->__ss;
87 mono_mach_arch_thread_state_to_mono_context (thread_state_t state, MonoContext *context)
90 arm_thread_state_t *arch_state = (arm_thread_state_t *) state;
91 for (i = 0; i < 13; ++i)
92 context->regs [i] = arch_state->__r [i];
93 context->regs [ARMREG_R13] = arch_state->__sp;
94 context->regs [ARMREG_R14] = arch_state->__lr;
95 context->regs [ARMREG_R15] = arch_state->__pc;
96 context->pc = arch_state->__pc;
97 context->cpsr = arch_state->__cpsr;
101 mono_mach_arch_get_thread_state_size ()
103 return sizeof (arm_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 #if defined(HOST_WATCHOS)
110 g_error ("thread_get_state() is not supported by this platform");
112 arm_thread_state_t *arch_state = (arm_thread_state_t *) state;
115 *count = ARM_THREAD_STATE_COUNT;
117 ret = thread_get_state (thread, ARM_THREAD_STATE, (thread_state_t) arch_state, count);
123 mono_mach_arch_set_thread_state (thread_port_t thread, thread_state_t state, mach_msg_type_number_t count)
125 #if defined(HOST_WATCHOS)
126 g_error ("thread_set_state() is not supported by this platform");
128 return thread_set_state (thread, ARM_THREAD_STATE, state, count);
133 mono_mach_get_tls_address_from_thread (pthread_t thread, pthread_key_t key)
135 /* Mach stores TLS values in a hidden array inside the pthread_t structure
136 * They are keyed off a giant array from a known offset into the pointer. This value
137 * is baked into their pthread_getspecific implementation
139 intptr_t *p = (intptr_t *) thread;
140 intptr_t **tsd = (intptr_t **) ((char*)p + tls_vector_offset);
141 g_assert (tls_vector_offset != -1);
143 return (void *) &tsd [key];
147 mono_mach_arch_get_tls_value_from_thread (pthread_t thread, guint32 key)
149 return *(void**)mono_mach_get_tls_address_from_thread (thread, key);
153 mono_mach_init (pthread_key_t key)
156 void *old_value = pthread_getspecific (key);
157 void *canary = (void*)0xDEADBEEFu;
159 pthread_key_create (&key, NULL);
160 g_assert (old_value != canary);
162 pthread_setspecific (key, canary);
164 /*First we probe for cats*/
165 for (i = 0; i < TLS_PROBE_COUNT; ++i) {
166 tls_vector_offset = known_tls_offsets [i];
167 if (mono_mach_arch_get_tls_value_from_thread (pthread_self (), key) == canary)
171 /*Fallback to scanning a large range of offsets*/
172 for (i = TLS_PROBE_LOW_WATERMARK; i <= TLS_PROBE_HIGH_WATERMARK; i += 4) {
173 tls_vector_offset = i;
174 if (mono_mach_arch_get_tls_value_from_thread (pthread_self (), key) == canary) {
175 g_warning ("Found new TLS offset at %d", i);
180 tls_vector_offset = -1;
181 g_warning ("could not discover the mach TLS offset");
183 pthread_setspecific (key, old_value);