diff options
Diffstat (limited to 'gcc/ada/init.c')
| -rw-r--r-- | gcc/ada/init.c | 65 |
1 files changed, 1 insertions, 64 deletions
diff --git a/gcc/ada/init.c b/gcc/ada/init.c index efc1a25..fd25d0d 100644 --- a/gcc/ada/init.c +++ b/gcc/ada/init.c @@ -386,7 +386,6 @@ __gnat_initialize (void) exclude this case in the above test. */ #include <signal.h> -#include <setjmp.h> #include <sys/siginfo.h> static void __gnat_error_handler (int, siginfo_t *, struct sigcontext *); @@ -404,7 +403,6 @@ __gnat_error_handler (int sig, siginfo_t *sip, struct sigcontext *context) static int recurse = 0; struct sigcontext *mstate; const char *msg; - jmp_buf handler_jmpbuf; /* If this was an explicit signal from a "kill", just resignal it. */ if (SI_FROMUSER (sip)) @@ -414,43 +412,6 @@ __gnat_error_handler (int sig, siginfo_t *sip, struct sigcontext *context) } /* Otherwise, treat it as something we handle. */ - - /* We are now going to raise the exception corresponding to the signal we - caught, which may eventually end up resuming the application code if the - exception is handled. - - When the exception is handled, merely arranging for the *exception* - handler's context (stack pointer, program counter, other registers, ...) - to be installed is *not* enough to let the kernel think we've left the - *signal* handler. This has annoying implications if an alternate stack - has been setup for this *signal* handler, because the kernel thinks we - are still running on that alternate stack even after the jump, which - causes trouble at least as soon as another signal is raised. - - We deal with this by forcing a "local" longjmp within the signal handler - below, forcing the "on alternate stack" indication to be reset (kernel - wise) on the way. If no alternate stack has been setup, this should be a - neutral operation. Otherwise, we will be in a delicate situation for a - short while because we are going to run the exception propagation code - within the alternate stack area (that is, with the stack pointer inside - the alternate stack bounds), but with the corresponding flag off from the - kernel's standpoint. We expect this to be ok as long as the propagation - code does not trigger a signal itself, which is expected. - - ??? A better approach would be to at least delay this operation until the - last second, that is, until just before we jump to the exception handler, - if any. */ - - if (setjmp (handler_jmpbuf) == 0) - { -#define JB_ONSIGSTK 0 - - /* Arrange for the "on alternate stack" flag to be reset. See the - comments around "jmp_buf offsets" in /usr/include/setjmp.h. */ - handler_jmpbuf [JB_ONSIGSTK] = 0; - longjmp (handler_jmpbuf, 1); - } - switch (sig) { case SIGSEGV: @@ -510,36 +471,12 @@ __gnat_install_handler (void) { struct sigaction act; - /* stack-checking on this platform is performed by the back-end and conforms - to what the ABI *mandates* (DEC OSF/1 Calling standard for AXP systems, - chapter 6: Stack Limits in Multihtreaded Execution Environments). This - does not include a "stack reserve" region, so nothing guarantees that - enough room remains on the current stack to propagate an exception when - a stack-overflow is signaled. We deal with this by requesting the use of - an alternate stack region for signal handlers. - - ??? The actual use of this alternate region depends on the act.sa_flags - including SA_ONSTACK below. Care should be taken to update s-intman if - we want this to happen for tasks also. */ - - static char sig_stack [8*1024]; - /* 8K is a mininum to be able to propagate an exception using the GCC/ZCX - scheme. */ - - struct sigaltstack ss; - - ss.ss_sp = (void *) sig_stack; - ss.ss_size = sizeof (sig_stack); - ss.ss_flags = 0; - - sigaltstack (&ss, 0); - /* Setup signal handler to map synchronous signals to appropriate exceptions. Make sure that the handler isn't interrupted by another signal that might cause a scheduling event! */ act.sa_handler = (void (*) (int)) __gnat_error_handler; - act.sa_flags = SA_ONSTACK | SA_RESTART | SA_NODEFER | SA_SIGINFO; + act.sa_flags = SA_RESTART | SA_NODEFER | SA_SIGINFO; sigemptyset (&act.sa_mask); /* Do not install handlers if interrupt state is "System" */ |