mono/utils/mach-support-arm64.c

   1 /*
   2  * mach-support-arm.c: mach support for ARM
   3  *
   4  * Authors:
   5  *   Geoff Norton (gnorton@novell.com)
   6  *   Rodrigo Kumpera (kumpera@gmail.com)
   7  *
   8  * (C) 2010 Novell, Inc.
   9  * (C) 2011 Xamarin, Inc.
  10  */
  11
  12 #include <config.h>
  13
  14 #if defined(__MACH__)
  15 #include <stdint.h>
  16 #include <glib.h>
  17 #include <pthread.h>
  18 #include "utils/mono-sigcontext.h"
  19 #include "utils/mono-compiler.h"
  20 #include "mach-support.h"
  21
  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
  25 #endif
  26
  27 /* Known offsets used for TLS storage*/
  28
  29
  30 static const int known_tls_offsets[] = {
  31         0x48, /*Found on iOS 6 */
  32         0xA4,
  33         0xA8,
  34 };
  35
  36 #define TLS_PROBE_COUNT (sizeof (known_tls_offsets) / sizeof (int))
  37
  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
  42
  43 static int tls_vector_offset;
  44
  45 void *
  46 mono_mach_arch_get_ip (thread_state_t state)
  47 {
  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;
  50
  51         return (void *) arch_state->ts_64.__pc;
  52 }
  53
  54 void *
  55 mono_mach_arch_get_sp (thread_state_t state)
  56 {
  57         arm_unified_thread_state_t *arch_state = (arm_unified_thread_state_t *) state;
  58
  59         return (void *) arch_state->ts_64.__sp;
  60 }
  61
  62 int
  63 mono_mach_arch_get_mcontext_size ()
  64 {
  65         return sizeof (struct __darwin_mcontext64);
  66 }
  67
  68 void
  69 mono_mach_arch_thread_states_to_mcontext (thread_state_t state, thread_state_t fpstate, void *context)
  70 {
  71         arm_unified_thread_state_t *arch_state = (arm_unified_thread_state_t *) state;
  72         struct __darwin_mcontext64 *ctx = (struct __darwin_mcontext64 *) context;
  73
  74         ctx->__ss = arch_state->ts_64;
  75 }
  76
  77 void
  78 mono_mach_arch_mcontext_to_thread_states (void *context, thread_state_t state, thread_state_t fpstate)
  79 {
  80         arm_unified_thread_state_t *arch_state = (arm_unified_thread_state_t *) state;
  81         struct __darwin_mcontext64 *ctx = (struct __darwin_mcontext64 *) context;
  82
  83         arch_state->ts_64 = ctx->__ss;
  84 }
  85
  86 void
  87 mono_mach_arch_thread_states_to_mono_context (thread_state_t state, thread_state_t fpstate, MonoContext *context)
  88 {
  89         int i;
  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];
  93
  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;
  98 }
  99
 100 int
 101 mono_mach_arch_get_thread_state_size ()
 102 {
 103         return sizeof (arm_unified_thread_state_t);
 104 }
 105
 106 int
 107 mono_mach_arch_get_thread_fpstate_size ()
 108 {
 109         g_assert_not_reached ();
 110 }
 111
 112 kern_return_t
 113 mono_mach_arch_get_thread_states (thread_port_t thread, thread_state_t state, mach_msg_type_number_t *count, thread_state_t fpstate, mach_msg_type_number_t *fpcount)
 114 {
 115         arm_unified_thread_state_t *arch_state = (arm_unified_thread_state_t *) state;
 116         kern_return_t ret;
 117
 118         *count = ARM_UNIFIED_THREAD_STATE_COUNT;
 119
 120         ret = thread_get_state (thread, ARM_UNIFIED_THREAD_STATE, (thread_state_t) arch_state, count);
 121         return ret;
 122 }
 123
 124 kern_return_t
 125 mono_mach_arch_set_thread_states (thread_port_t thread, thread_state_t state, mach_msg_type_number_t count, thread_state_t fpstate, mach_msg_type_number_t fpcount)
 126 {
 127         return thread_set_state (thread, ARM_UNIFIED_THREAD_STATE, state, count);
 128 }
 129
 130 void *
 131 mono_mach_get_tls_address_from_thread (pthread_t thread, pthread_key_t key)
 132 {
 133         /* Mach stores TLS values in a hidden array inside the pthread_t structure
 134          * They are keyed off a giant array from a known offset into the pointer. This value
 135          * is baked into their pthread_getspecific implementation
 136          */
 137         intptr_t *p = (intptr_t *) thread;
 138         intptr_t **tsd = (intptr_t **) ((char*)p + tls_vector_offset);
 139         g_assert (tls_vector_offset != -1);
 140
 141         return (void *) &tsd [key];
 142 }
 143
 144 void *
 145 mono_mach_arch_get_tls_value_from_thread (pthread_t thread, guint32 key)
 146 {
 147         return *(void**)mono_mach_get_tls_address_from_thread (thread, key);
 148 }
 149
 150 void
 151 mono_mach_init (pthread_key_t key)
 152 {
 153         int i;
 154         void *old_value = pthread_getspecific (key);
 155         void *canary = (void*)0xDEADBEEFu;
 156
 157         pthread_key_create (&key, NULL);
 158         g_assert (old_value != canary);
 159
 160         pthread_setspecific (key, canary);
 161
 162         /*First we probe for cats*/
 163         for (i = 0; i < TLS_PROBE_COUNT; ++i) {
 164                 tls_vector_offset = known_tls_offsets [i];
 165                 if (mono_mach_arch_get_tls_value_from_thread (pthread_self (), key) == canary)
 166                         goto ok;
 167         }
 168
 169         /*Fallback to scanning a large range of offsets*/
 170         for (i = TLS_PROBE_LOW_WATERMARK; i <= TLS_PROBE_HIGH_WATERMARK; i += 4) {
 171                 tls_vector_offset = i;
 172                 if (mono_mach_arch_get_tls_value_from_thread (pthread_self (), key) == canary) {
 173                         g_warning ("Found new TLS offset at %d", i);
 174                         goto ok;
 175                 }
 176         }
 177
 178         tls_vector_offset = -1;
 179         g_warning ("could not discover the mach TLS offset");
 180 ok:
 181         pthread_setspecific (key, old_value);
 182 }
 183
 184 #endif