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 arm_thread_state_t
*arch_state
= (arm_thread_state_t
*) state
;
50 return (void *) arch_state
->__pc
;
54 mono_mach_arch_get_sp (thread_state_t state
)
56 arm_thread_state_t
*arch_state
= (arm_thread_state_t
*) state
;
58 return (void *) arch_state
->__sp
;
62 mono_mach_arch_get_mcontext_size ()
64 return sizeof (struct __darwin_mcontext
);
68 mono_mach_arch_thread_state_to_mcontext (thread_state_t state
, void *context
)
70 arm_thread_state_t
*arch_state
= (arm_thread_state_t
*) state
;
71 struct __darwin_mcontext
*ctx
= (struct __darwin_mcontext
*) context
;
73 ctx
->__ss
= *arch_state
;
77 mono_mach_arch_mcontext_to_thread_state (void *context
, thread_state_t state
)
79 arm_thread_state_t
*arch_state
= (arm_thread_state_t
*) state
;
80 struct __darwin_mcontext
*ctx
= (struct __darwin_mcontext
*) context
;
82 *arch_state
= ctx
->__ss
;
86 mono_mach_arch_get_thread_state_size ()
88 return sizeof (arm_thread_state_t
);
92 mono_mach_arch_get_thread_state (thread_port_t thread
, thread_state_t state
, mach_msg_type_number_t
*count
)
94 arm_thread_state_t
*arch_state
= (arm_thread_state_t
*) state
;
97 *count
= ARM_THREAD_STATE_COUNT
;
99 ret
= thread_get_state (thread
, ARM_THREAD_STATE
, (thread_state_t
) arch_state
, count
);
105 mono_mach_arch_set_thread_state (thread_port_t thread
, thread_state_t state
, mach_msg_type_number_t count
)
107 return thread_set_state (thread
, ARM_THREAD_STATE_COUNT
, state
, count
);
111 mono_mach_get_tls_address_from_thread (pthread_t thread
, pthread_key_t key
)
113 /* Mach stores TLS values in a hidden array inside the pthread_t structure
114 * They are keyed off a giant array from a known offset into the pointer. This value
115 * is baked into their pthread_getspecific implementation
117 intptr_t *p
= (intptr_t *) thread
;
118 intptr_t **tsd
= (intptr_t **) ((char*)p
+ tls_vector_offset
);
120 return (void *) &tsd
[key
];
124 mono_mach_arch_get_tls_value_from_thread (pthread_t thread
, guint32 key
)
126 return *(void**)mono_mach_get_tls_address_from_thread (thread
, key
);
130 mono_mach_init (pthread_key_t key
)
133 void *old_value
= pthread_getspecific (key
);
134 void *canary
= (void*)0xDEADBEEFu
;
136 pthread_key_create (&key
, NULL
);
137 g_assert (old_value
!= canary
);
139 pthread_setspecific (key
, canary
);
141 /*First we probe for cats*/
142 for (i
= 0; i
< TLS_PROBE_COUNT
; ++i
) {
143 tls_vector_offset
= known_tls_offsets
[i
];
144 if (mono_mach_arch_get_tls_value_from_thread (pthread_self (), key
) == canary
)
148 /*Fallback to scanning a large range of offsets*/
149 for (i
= TLS_PROBE_LOW_WATERMARK
; i
<= TLS_PROBE_HIGH_WATERMARK
; i
+= 4) {
150 tls_vector_offset
= i
;
151 if (mono_mach_arch_get_tls_value_from_thread (pthread_self (), key
) == canary
) {
152 g_warning ("Found new TLS offset at %d", i
);
157 g_error ("could not discover the mach TLS offset");
159 pthread_setspecific (key
, old_value
);