Mps: implemented prot on os x.

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 Change: 147629
 ServerID: perforce.ravenbrook.com

1 files changed, 215 insertions, 0 deletions

diff --git a/mps/code/protxcpp.c b/mps/code/protxcpp.c
new file mode 100644
index 00000000000..44c95b25b7f
--- /dev/null
+++ b/mps/code/protxcpp.c
@@ -0,0 +1,215 @@
+/* protxcpp.c: PROTECTION FOR MAC OS X ON POWERPC
+ *
+ *  $Header$
+ *  Copyright (c) 2001,2005 Ravenbrook Limited.  See end of file for license.
+ *
+ *  Most of this was copied from protso.c and modified.
+ *
+ *  REFERENCES
+ *
+ * [PEM] "PowerPC Microprocessor Family: The Programming Environments for
+ * 32-bit Microprocessors", Motorola, 1997-01.  MPCFPE32B/AD REV.1
+ *
+ * [SIGNALH] /usr/include/sys/signal.h on drj's iBook (Mac OS X 10.3.8)
+ *
+ * [PPCUCH] /usr/include/ppc/ucontext.h
+ *
+ */
+
+#include "mpm.h"
+
+#ifndef MPS_OS_XC
+#error "protxcpp.c is Mac OS X specific, but MPS_OS_XC is not set"
+#endif
+#ifndef MPS_ARCH_PP
+#error "protxcpp.c is PowerPC specific, but MPS_ARCH_PP is not set"
+#endif
+#ifndef PROTECTION
+#error "protxcpp.c implements protection, but PROTECTION is not set"
+#endif
+
+#include <signal.h>
+#include <sys/ucontext.h>
+
+#include <stdio.h> /* DO NOT SUBMIT */
+
+SRCID(protxcpp, "$Id$");
+
+/* The previously-installed signal action, as returned by */
+/* sigaction(3).  See ProtSetup. */
+
+static struct sigaction sigNext;
+
+/* sigHandle -- protection signal handler
+ *
+ *  This is the signal handler installed by ProtSetup to deal with
+ *  protection faults.  It is installed on the SIGBUS signal.
+ *  It decodes the protection fault details from the signal context
+ *  and passes them to ArenaAccess, which attempts to handle the
+ *  fault and remove its cause.  If the fault is handled, then
+ *  the handler returns and execution resumes.  If it isn't handled,
+ *  then sigHandle does its best to pass the signal on to the
+ *  previously installed signal handler (sigNext).
+ *
+ *  .sigh.addr: si_addr, on Darwin 7.8.0, is the address of the faulting
+ *  instruction (by observation). [SIGNALH] says, in the declaration of
+ *  siginfo_t, that this field should be the faulting instruction, but
+ *  below that says that for SIGBUS it should be the faulting address).
+ *  We grub around in the ucontext to find the PowerPC DAR register (See
+ *  [PEM] 6-25, Table 6-9) which contains the faulting address.
+ *
+ *  .sigh.limit: We throw away the limit information.
+ */
+
+static void sigHandle(int sig, siginfo_t *info, void *contextArg)
+{
+  ucontext_t *ucontext;
+
+  AVER(sig == SIGBUS);
+  AVER(info != NULL);
+
+  ucontext = contextArg;
+
+  {
+    int i;
+    fprintf(stderr, "sigHandle.\n");
+
+    for(i=0; i < sizeof *info; ++i) {
+      fprintf(stderr, "%02x", ((unsigned char *)info)[i]);
+    }
+    fprintf(stderr, "\n");
+    fprintf(stderr, "signo: %d, code %d, addr %p\n",
+      info->si_signo, info->si_code, info->si_addr);
+
+    fprintf(stderr, "ucontext:\n");
+    for(i=0; i < sizeof *ucontext; ++i) {
+      fprintf(stderr, "%02x ", ((unsigned char *)ucontext)[i]);
+    }
+    fprintf(stderr, "\n");
+    fprintf(stderr, "uc_mcontext:\n");
+    for(i=0; i< sizeof ucontext->uc_mcontext; ++i) {
+      fprintf(stderr, "%02x ", ((unsigned char *)&ucontext->uc_mcontext)[i]);
+    }
+    fprintf(stderr, "\n");
+    fprintf(stderr, "uc_mcontext->es.dar: %08lx\n",
+      (unsigned long)ucontext->uc_mcontext->es.dar);
+  }
+
+  /* On OS X the si_code field does't appear to be useful.  Protection
+   * faults appear as SIGBUS signals, and the only documented code for
+   * SIGBUS is BUS_ADRALN (invalid address alignment) which is what
+   * si_code is set to (it has value 1), even though the address is
+   * in fact aligned.
+   * On other platforms a test like info->si_code == SEGV_ACCERR appears
+   * here. */
+  if(1) {
+    AccessSet mode;
+    Addr base, limit;
+
+    /* We dont't bother to determine the access mode (read, write, etc.)
+     * under OS X.  It's possible that this information is available in
+     * the context structures.  Needs more investigation.
+     */
+
+    mode = AccessREAD | AccessWRITE;
+
+    /* We assume that the access is for one word at the address. */
+
+    /* See [PPCUCH] */
+    base = (Addr)ucontext->uc_mcontext->es.dar;
+    limit = AddrAdd(base, (Size)sizeof(Addr));
+
+    /* Offer each protection structure the opportunity to handle the */
+    /* exception.  If it succeeds, then allow the mutator to continue. */
+
+    /* MutatorFaultContext parameter is a dummy parameter for this */
+    /* implementation */
+    fprintf(stderr, "access: base: %08x mode: %08x\n", (unsigned)base, mode);
+    if(ArenaAccess(base, mode, NULL)) {
+      fprintf(stderr, "returning\n");
+      return;
+    }
+  }
+
+  /* The exception was not handled by any known protection structure, */
+  /* so throw it to the previously installed handler. */
+
+  fprintf(stderr, "Throwing to %08x\n", (unsigned)sigNext.sa_sigaction);
+
+  /* @@ This is really weak.
+   * Need to implement rest of the contract of sigaction */
+  (*sigNext.sa_sigaction)(sig, info, contextArg);
+}
+
+
+/*  ProtSetup -- global protection setup
+ *
+ *  Under OS X, the global setup involves installing a signal handler
+ *  on SIGBUS to catch and handle protection faults (see sigHandle).
+ *  The previous handler is recorded so that it can be reached from
+ *  sigHandle if it fails to handle the fault.
+ *
+ *  NOTE: There are problems with this approach:
+ *    1. we can't honor the wishes of the sigvec(2) entry for the
+ *       previous handler,
+ */
+
+/* This function itself probably isn't architecture specific, but it
+ * references the sigHandle which is currently statis and which is
+ * architecture specific. */
+void ProtSetup(void)
+{
+  struct sigaction sa;
+  int result;
+
+  sa.sa_sigaction = sigHandle;
+  /* No idea if sigemptyset is necessary, copied from protfri3.c,
+   * 2005-03-02 DRJ */
+  sigemptyset(&sa.sa_mask);
+  sa.sa_flags = SA_SIGINFO;
+
+  result = sigaction(SIGBUS, &sa, &sigNext);
+  AVER(result == 0);
+}
+
+
+/* C. COPYRIGHT AND LICENSE
+ *
+ * Copyright (C) 2001-2002,2005 Ravenbrook Limited <http://www.ravenbrook.com/>.
+ * All rights reserved.  This is an open source license.  Contact
+ * Ravenbrook for commercial licensing options.
+ * 
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met:
+ * 
+ * 1. Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ * 
+ * 2. Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in the
+ * documentation and/or other materials provided with the distribution.
+ * 
+ * 3. Redistributions in any form must be accompanied by information on how
+ * to obtain complete source code for this software and any accompanying
+ * software that uses this software.  The source code must either be
+ * included in the distribution or be available for no more than the cost
+ * of distribution plus a nominal fee, and must be freely redistributable
+ * under reasonable conditions.  For an executable file, complete source
+ * code means the source code for all modules it contains. It does not
+ * include source code for modules or files that typically accompany the
+ * major components of the operating system on which the executable file
+ * runs.
+ * 
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
+ * IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
+ * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR
+ * PURPOSE, OR NON-INFRINGEMENT, ARE DISCLAIMED. IN NO EVENT SHALL THE
+ * COPYRIGHT HOLDERS AND CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
+ * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
+ * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
+ * ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
+ * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */