mono/utils/mach-support-arm64.c

   1 /**
   2  * \file
   3  * mach support for ARM
   4  *
   5  * Authors:
   6  *   Geoff Norton (gnorton@novell.com)
   7  *   Rodrigo Kumpera (kumpera@gmail.com)
   8  *
   9  * (C) 2010 Novell, Inc.
  10  * (C) 2011 Xamarin, Inc.
  11  */
  12
  13 #include <config.h>
  14
  15 #if defined(__MACH__)
  16 #include <stdint.h>
  17 #include <glib.h>
  18 #include <pthread.h>
  19 #include "utils/mono-sigcontext.h"
  20 #include "utils/mono-compiler.h"
  21 #include "mach-support.h"
  22
  23 /* _mcontext.h now defines __darwin_mcontext32, not __darwin_mcontext, starting with Xcode 5.1 */
  24 #ifdef _STRUCT_MCONTEXT32
  25        #define __darwin_mcontext       __darwin_mcontext32
  26 #endif
  27
  28 /* Known offsets used for TLS storage*/
  29
  30
  31 static const int known_tls_offsets[] = {
  32         0x48, /*Found on iOS 6 */
  33         0xA4,
  34         0xA8,
  35 };
  36
  37 #define TLS_PROBE_COUNT (sizeof (known_tls_offsets) / sizeof (int))
  38
  39 /* This is 2 slots less than the known low */
  40 #define TLS_PROBE_LOW_WATERMARK 0x40
  41 /* This is 24 slots above the know high, which is the same diff as the knowns high-low*/
  42 #define TLS_PROBE_HIGH_WATERMARK 0x108
  43
  44 static int tls_vector_offset;
  45
  46 void *
  47 mono_mach_arch_get_ip (thread_state_t state)
  48 {
  49         /* Can't use unified_thread_state on !ARM64 since this has to compile on armv6 too */
  50         arm_unified_thread_state_t *arch_state = (arm_unified_thread_state_t *) state;
  51
  52         return (void *) arch_state->ts_64.__pc;
  53 }
  54
  55 void *
  56 mono_mach_arch_get_sp (thread_state_t state)
  57 {
  58         arm_unified_thread_state_t *arch_state = (arm_unified_thread_state_t *) state;
  59
  60         return (void *) arch_state->ts_64.__sp;
  61 }
  62
  63 int
  64 mono_mach_arch_get_mcontext_size ()
  65 {
  66         return sizeof (struct __darwin_mcontext64);
  67 }
  68
  69 void
  70 mono_mach_arch_thread_states_to_mcontext (thread_state_t state, thread_state_t fpstate, void *context)
  71 {
  72         arm_unified_thread_state_t *arch_state = (arm_unified_thread_state_t *) state;
  73         struct __darwin_mcontext64 *ctx = (struct __darwin_mcontext64 *) context;
  74
  75         ctx->__ss = arch_state->ts_64;
  76 }
  77
  78 void
  79 mono_mach_arch_mcontext_to_thread_states (void *context, thread_state_t state, thread_state_t fpstate)
  80 {
  81         arm_unified_thread_state_t *arch_state = (arm_unified_thread_state_t *) state;
  82         struct __darwin_mcontext64 *ctx = (struct __darwin_mcontext64 *) context;
  83
  84         arch_state->ts_64 = ctx->__ss;
  85 }
  86
  87 void
  88 mono_mach_arch_thread_states_to_mono_context (thread_state_t state, thread_state_t fpstate, MonoContext *context)
  89 {
  90         int i;
  91         arm_unified_thread_state_t *arch_state = (arm_unified_thread_state_t *) state;
  92         for (i = 0; i < 29; ++i)
  93                 context->regs [i] = arch_state->ts_64.__x [i];
  94
  95         context->regs [ARMREG_R29] = arch_state->ts_64.__fp;
  96         context->regs [ARMREG_R30] = arch_state->ts_64.__lr;
  97         context->regs [ARMREG_SP] = arch_state->ts_64.__sp;
  98         context->pc = arch_state->ts_64.__pc;
  99 }
 100
 101 int
 102 mono_mach_arch_get_thread_state_size ()
 103 {
 104         return sizeof (arm_unified_thread_state_t);
 105 }
 106
 107 int
 108 mono_mach_arch_get_thread_fpstate_size ()
 109 {
 110         return sizeof (arm_neon_state64_t);
 111 }
 112
 113 kern_return_t
 114 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)
 115 {
 116         arm_unified_thread_state_t *arch_state = (arm_unified_thread_state_t *) state;
 117         kern_return_t ret;
 118
 119         *count = ARM_UNIFIED_THREAD_STATE_COUNT;
 120
 121         ret = thread_get_state (thread, ARM_UNIFIED_THREAD_STATE, (thread_state_t) arch_state, count);
 122         return ret;
 123 }
 124
 125 kern_return_t
 126 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)
 127 {
 128         return thread_set_state (thread, ARM_UNIFIED_THREAD_STATE, state, count);
 129 }
 130
 131 void *
 132 mono_mach_get_tls_address_from_thread (pthread_t thread, pthread_key_t key)
 133 {
 134         /* Mach stores TLS values in a hidden array inside the pthread_t structure
 135          * They are keyed off a giant array from a known offset into the pointer. This value
 136          * is baked into their pthread_getspecific implementation
 137          */
 138         intptr_t *p = (intptr_t *) thread;
 139         intptr_t **tsd = (intptr_t **) ((char*)p + tls_vector_offset);
 140         g_assert (tls_vector_offset != -1);
 141
 142         return (void *) &tsd [key];
 143 }
 144
 145 void *
 146 mono_mach_arch_get_tls_value_from_thread (pthread_t thread, guint32 key)
 147 {
 148         return *(void**)mono_mach_get_tls_address_from_thread (thread, key);
 149 }
 150
 151 void
 152 mono_mach_init (pthread_key_t key)
 153 {
 154         int i;
 155         void *old_value = pthread_getspecific (key);
 156         void *canary = (void*)0xDEADBEEFu;
 157
 158         pthread_key_create (&key, NULL);
 159         g_assert (old_value != canary);
 160
 161         pthread_setspecific (key, canary);
 162
 163         /*First we probe for cats*/
 164         for (i = 0; i < TLS_PROBE_COUNT; ++i) {
 165                 tls_vector_offset = known_tls_offsets [i];
 166                 if (mono_mach_arch_get_tls_value_from_thread (pthread_self (), key) == canary)
 167                         goto ok;
 168         }
 169
 170         /*Fallback to scanning a large range of offsets*/
 171         for (i = TLS_PROBE_LOW_WATERMARK; i <= TLS_PROBE_HIGH_WATERMARK; i += 4) {
 172                 tls_vector_offset = i;
 173                 if (mono_mach_arch_get_tls_value_from_thread (pthread_self (), key) == canary) {
 174                         g_warning ("Found new TLS offset at %d", i);
 175                         goto ok;
 176                 }
 177         }
 178
 179         tls_vector_offset = -1;
 180         g_warning ("could not discover the mach TLS offset");
 181 ok:
 182         pthread_setspecific (key, old_value);
 183 }
 184
 185 #endif