(CFLAGS-tst-align.c): Add -mpreferred-stack-boundary=4.

1 files changed, 116 insertions, 0 deletions

diff --git a/linuxthreads/tst-context.c b/linuxthreads/tst-context.c
new file mode 100644
index 0000000000..2938a9f7fa
--- /dev/null
+++ b/linuxthreads/tst-context.c
@@ -0,0 +1,116 @@
+/* Ack, a hack!  We need to get the proper definition, or lack thereof,
+   for FLOATING_STACKS.  But when !IS_IN_libpthread, this can get defined
+   incidentally by <tls.h>.  So kludge around it.  */
+
+#define IS_IN_libpthread
+#include <tls.h>
+#undef IS_IN_libpthread
+#undef USE___THREAD
+
+#include <errno.h>
+#include <error.h>
+#include <pthread.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <ucontext.h>
+
+
+#define N	4
+
+#ifdef FLOATING_STACKS
+static char stacks[N][8192];
+static ucontext_t ctx[N][2];
+static volatile int failures;
+
+static void
+fct (long int n)
+{
+  /* Just to use the thread local descriptor.  */
+  printf ("%ld: in %s now\n", n, __FUNCTION__);
+  errno = 0;
+}
+
+static void *
+threadfct (void *arg)
+{
+  int n = (int) (long int) arg;
+
+  if (getcontext (&ctx[n][1]) != 0)
+    {
+      printf ("%d: cannot get context: %m\n", n);
+      exit (1);
+    }
+
+  printf ("%d: %s: before makecontext\n", n, __FUNCTION__);
+
+  ctx[n][1].uc_stack.ss_sp = stacks[n];
+  ctx[n][1].uc_stack.ss_size = 8192;
+  ctx[n][1].uc_link = &ctx[n][0];
+  makecontext (&ctx[n][1], (void (*) (void)) fct, 1, (long int) n);
+
+  printf ("%d: %s: before swapcontext\n", n, __FUNCTION__);
+
+  if (swapcontext (&ctx[n][0], &ctx[n][1]) != 0)
+    {
+      ++failures;
+      printf ("%d: %s: swapcontext failed\n", n, __FUNCTION__);
+    }
+  else
+    printf ("%d: back in %s\n", n, __FUNCTION__);
+
+  return NULL;
+}
+#endif
+
+
+#ifdef FLOATING_STACKS
+static volatile int global;
+#endif
+
+int
+main (void)
+{
+#ifndef FLOATING_STACKS
+  puts ("not supported");
+  return 0;
+#else
+  int n;
+  pthread_t th[N];
+  ucontext_t mctx;
+
+  puts ("making contexts");
+  if (getcontext (&mctx) != 0)
+    {
+      if (errno == ENOSYS)
+	{
+	  puts ("context handling not supported");
+	  exit (0);
+	}
+
+      printf ("%s: getcontext: %m\n", __FUNCTION__);
+      exit (1);
+    }
+
+  /* Play some tricks with this context.  */
+  if (++global == 1)
+    if (setcontext (&mctx) != 0)
+      {
+	printf ("%s: setcontext: %m\n", __FUNCTION__);
+	exit (1);
+      }
+  if (global != 2)
+    {
+      printf ("%s: 'global' not incremented twice\n", __FUNCTION__);
+      exit (1);
+    }
+
+  for (n = 0; n < N; ++n)
+    if (pthread_create (&th[n], NULL, threadfct, (void *) (long int) n) != 0)
+      error (EXIT_FAILURE, errno, "cannot create all threads");
+
+  for (n = 0; n < N; ++n)
+    pthread_join (th[n], NULL);
+
+  return failures;
+#endif
+}