1------------------------------------------------------------------------------ 2-- -- 3-- GNAT RUN-TIME LIBRARY (GNARL) COMPONENTS -- 4-- -- 5-- S Y S T E M . I N T E R R U P T _ M A N A G E M E N T -- 6-- -- 7-- B o d y -- 8-- -- 9-- Copyright (C) 2014, Free Software Foundation, Inc. -- 10-- -- 11-- GNARL is free software; you can redistribute it and/or modify it under -- 12-- terms of the GNU General Public License as published by the Free Soft- -- 13-- ware Foundation; either version 3, or (at your option) any later ver- -- 14-- sion. GNAT is distributed in the hope that it will be useful, but WITH- -- 15-- OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY -- 16-- or FITNESS FOR A PARTICULAR PURPOSE. -- 17-- -- 18-- As a special exception under Section 7 of GPL version 3, you are granted -- 19-- additional permissions described in the GCC Runtime Library Exception, -- 20-- version 3.1, as published by the Free Software Foundation. -- 21-- -- 22-- In particular, you can freely distribute your programs built with the -- 23-- GNAT Pro compiler, including any required library run-time units, using -- 24-- any licensing terms of your choosing. See the AdaCore Software License -- 25-- for full details. -- 26-- -- 27-- GNARL was developed by the GNARL team at Florida State University. -- 28-- Extensive contributions were provided by Ada Core Technologies, Inc. -- 29-- -- 30------------------------------------------------------------------------------ 31 32-- This is the Android version of this package 33 34-- Make a careful study of all signals available under the OS, to see which 35-- need to be reserved, kept always unmasked, or kept always unmasked. Be on 36-- the lookout for special signals that may be used by the thread library. 37 38-- Since this is a multi target file, the signal <-> exception mapping 39-- is simple minded. If you need a more precise and target specific 40-- signal handling, create a new s-intman.adb that will fit your needs. 41 42-- This file assumes that: 43 44-- SIGFPE, SIGILL, SIGSEGV and SIGBUS exist. They are mapped as follows: 45-- SIGPFE => Constraint_Error 46-- SIGILL => Program_Error 47-- SIGSEGV => Storage_Error 48-- SIGBUS => Storage_Error 49 50-- SIGINT exists and will be kept unmasked unless the pragma 51-- Unreserve_All_Interrupts is specified anywhere in the application. 52 53-- System.OS_Interface contains the following: 54-- SIGADAABORT: the signal that will be used to abort tasks. 55-- Unmasked: the OS specific set of signals that should be unmasked in 56-- all the threads. SIGADAABORT is unmasked by 57-- default 58-- Reserved: the OS specific set of signals that are reserved. 59 60with System.Task_Primitives; 61 62package body System.Interrupt_Management is 63 64 use Interfaces.C; 65 use System.OS_Interface; 66 67 type Interrupt_List is array (Interrupt_ID range <>) of Interrupt_ID; 68 Exception_Interrupts : constant Interrupt_List := 69 (SIGFPE, SIGILL, SIGSEGV, SIGBUS); 70 71 Unreserve_All_Interrupts : Interfaces.C.int; 72 pragma Import 73 (C, Unreserve_All_Interrupts, "__gl_unreserve_all_interrupts"); 74 75 ----------------------- 76 -- Local Subprograms -- 77 ----------------------- 78 79 procedure Signal_Trampoline 80 (signo : Signal; 81 siginfo : System.Address; 82 ucontext : System.Address; 83 handler : System.Address); 84 pragma Import (C, Signal_Trampoline, "__gnat_sigtramp"); 85 -- Pass the real handler to a speical function that handles unwinding by 86 -- skipping over the kernel signal frame (which doesn't contain any unwind 87 -- information). 88 89 function State (Int : Interrupt_ID) return Character; 90 pragma Import (C, State, "__gnat_get_interrupt_state"); 91 -- Get interrupt state. Defined in init.c The input argument is the 92 -- interrupt number, and the result is one of the following: 93 94 procedure Map_Signal 95 (signo : Signal; 96 siginfo : System.Address; 97 ucontext : System.Address); 98 -- This function identifies the Ada exception to be raised using the 99 -- information when the system received a synchronous signal. 100 101---------------- 102-- Map_Signal -- 103---------------- 104 105 procedure Map_Signal 106 (signo : Signal; 107 siginfo : System.Address; 108 ucontext : System.Address) 109 is 110 pragma Unreferenced (siginfo); 111 pragma Unreferenced (ucontext); 112 113 begin 114 115 -- Check that treatment of exception propagation here is consistent with 116 -- treatment of the abort signal in System.Task_Primitives.Operations. 117 118 case signo is 119 when SIGFPE => 120 raise Constraint_Error; 121 when SIGILL => 122 raise Program_Error; 123 when SIGSEGV => 124 raise Storage_Error; 125 when SIGBUS => 126 raise Storage_Error; 127 when others => 128 null; 129 end case; 130 end Map_Signal; 131 132---------------------- 133-- Notify_Exception -- 134---------------------- 135 136 User : constant Character := 'u'; 137 Runtime : constant Character := 'r'; 138 Default : constant Character := 's'; 139 -- 'n' this interrupt not set by any Interrupt_State pragma 140 -- 'u' Interrupt_State pragma set state to User 141 -- 'r' Interrupt_State pragma set state to Runtime 142 -- 's' Interrupt_State pragma set state to System (use "default" 143 -- system handler) 144 145 procedure Notify_Exception 146 (signo : Signal; 147 siginfo : System.Address; 148 ucontext : System.Address); 149 -- This function is the signal handler and calls a trampoline subprogram 150 -- that adjusts the unwind information so the ARM unwinder can find it's 151 -- way back to the context of the originating subprogram. Compare with 152 -- __gnat_error_handler for non-tasking programs. 153 154 ---------------------- 155 -- Notify_Exception -- 156 ---------------------- 157 158 Signal_Mask : aliased sigset_t; 159 -- The set of signals handled by Notify_Exception 160 161 procedure Notify_Exception 162 (signo : Signal; 163 siginfo : System.Address; 164 ucontext : System.Address) 165 is 166 Result : Interfaces.C.int; 167 168 begin 169 -- With the __builtin_longjmp, the signal mask is not restored, so we 170 -- need to restore it explicitly. ??? We don't use __builtin_longjmp 171 -- anymore, so do we still need this? */ 172 173 Result := pthread_sigmask (SIG_UNBLOCK, Signal_Mask'Access, null); 174 pragma Assert (Result = 0); 175 176 -- Perform the necessary context adjustments prior to calling the 177 -- trampoline subprogram with the "real" signal handler. 178 179 Adjust_Context_For_Raise (signo, ucontext); 180 181 Signal_Trampoline (signo, siginfo, ucontext, Map_Signal'Address); 182 end Notify_Exception; 183 184 ---------------- 185 -- Initialize -- 186 ---------------- 187 188 Initialized : Boolean := False; 189 190 procedure Initialize is 191 act : aliased struct_sigaction; 192 old_act : aliased struct_sigaction; 193 Result : System.OS_Interface.int; 194 195 Use_Alternate_Stack : constant Boolean := 196 System.Task_Primitives.Alternate_Stack_Size /= 0; 197 -- Whether to use an alternate signal stack for stack overflows 198 199 begin 200 if Initialized then 201 return; 202 end if; 203 204 Initialized := True; 205 206 -- Need to call pthread_init very early because it is doing signal 207 -- initializations. 208 209 pthread_init; 210 211 Abort_Task_Interrupt := SIGADAABORT; 212 213 act.sa_handler := Notify_Exception'Address; 214 215 -- Setting SA_SIGINFO asks the kernel to pass more than just the signal 216 -- number argument to the handler when it is called. The set of extra 217 -- parameters includes a pointer to the interrupted context, which the 218 -- ZCX propagation scheme needs. 219 220 -- Most man pages for sigaction mention that sa_sigaction should be set 221 -- instead of sa_handler when SA_SIGINFO is on. In practice, the two 222 -- fields are actually union'ed and located at the same offset. 223 224 -- On some targets, we set sa_flags to SA_NODEFER so that during the 225 -- handler execution we do not change the Signal_Mask to be masked for 226 -- the Signal. 227 228 -- This is a temporary fix to the problem that the Signal_Mask is not 229 -- restored after the exception (longjmp) from the handler. The right 230 -- fix should be made in sigsetjmp so that we save the Signal_Set and 231 -- restore it after a longjmp. 232 233 -- We set SA_NODEFER to be compatible with what is done in 234 -- __gnat_error_handler. 235 236 Result := sigemptyset (Signal_Mask'Access); 237 pragma Assert (Result = 0); 238 239 -- Add signals that map to Ada exceptions to the mask 240 241 for J in Exception_Interrupts'Range loop 242 if State (Exception_Interrupts (J)) /= Default then 243 Result := 244 sigaddset 245 (Signal_Mask'Access, Signal (Exception_Interrupts (J))); 246 pragma Assert (Result = 0); 247 end if; 248 end loop; 249 250 act.sa_mask := Signal_Mask; 251 252 pragma Assert (Keep_Unmasked = (Interrupt_ID'Range => False)); 253 pragma Assert (Reserve = (Interrupt_ID'Range => False)); 254 255 -- Process state of exception signals 256 257 for J in Exception_Interrupts'Range loop 258 if State (Exception_Interrupts (J)) /= User then 259 Keep_Unmasked (Exception_Interrupts (J)) := True; 260 Reserve (Exception_Interrupts (J)) := True; 261 262 if State (Exception_Interrupts (J)) /= Default then 263 act.sa_flags := SA_NODEFER + SA_RESTART + SA_SIGINFO; 264 265 if Use_Alternate_Stack 266 and then Exception_Interrupts (J) = SIGSEGV 267 then 268 act.sa_flags := act.sa_flags + SA_ONSTACK; 269 end if; 270 271 Result := 272 sigaction 273 (Signal (Exception_Interrupts (J)), act'Unchecked_Access, 274 old_act'Unchecked_Access); 275 pragma Assert (Result = 0); 276 end if; 277 end if; 278 end loop; 279 280 if State (Abort_Task_Interrupt) /= User then 281 Keep_Unmasked (Abort_Task_Interrupt) := True; 282 Reserve (Abort_Task_Interrupt) := True; 283 end if; 284 285 -- Set SIGINT to unmasked state as long as it is not in "User" state. 286 -- Check for Unreserve_All_Interrupts last. 287 288 if State (SIGINT) /= User then 289 Keep_Unmasked (SIGINT) := True; 290 Reserve (SIGINT) := True; 291 end if; 292 293 -- Check all signals for state that requires keeping them unmasked and 294 -- reserved. 295 296 for J in Interrupt_ID'Range loop 297 if State (J) = Default or else State (J) = Runtime then 298 Keep_Unmasked (J) := True; 299 Reserve (J) := True; 300 end if; 301 end loop; 302 303 -- Add the set of signals that must always be unmasked for this target 304 305 for J in Unmasked'Range loop 306 Keep_Unmasked (Interrupt_ID (Unmasked (J))) := True; 307 Reserve (Interrupt_ID (Unmasked (J))) := True; 308 end loop; 309 310 -- Add target-specific reserved signals 311 312 for J in Reserved'Range loop 313 Reserve (Interrupt_ID (Reserved (J))) := True; 314 end loop; 315 316 -- Process pragma Unreserve_All_Interrupts. This overrides any settings 317 -- due to pragma Interrupt_State: 318 319 if Unreserve_All_Interrupts /= 0 then 320 Keep_Unmasked (SIGINT) := False; 321 Reserve (SIGINT) := False; 322 end if; 323 324 -- We do not really have Signal 0. We just use this value to identify 325 -- non-existent signals (see s-intnam.ads). Therefore, Signal should not 326 -- be used in all signal related operations hence mark it as reserved. 327 328 Reserve (0) := True; 329 end Initialize; 330 331end System.Interrupt_Management; 332