configurator: Add test for ucontext.h

This adds a new HAVE_UCONTEXT define, which indicates that ucontext.h
is present, and more-or-less works.

It also adds HAVE_POINTER_SAFE_MAKECONTEXT, which indicates whether
pointer valued arguments can be passed through the varargs parameters
to makecontext().

Signed-off-by: David Gibson <david@gibson.dropbear.id.au>

diff --git a/tools/configurator/configurator.c b/tools/configurator/configurator.c
index 021fc0f9f183a711f67231625dc04da3c615440d..370170b80c5866acf0151038e59bedcf6d39c787 100644 (file)
--- a/tools/configurator/configurator.c
+++ b/tools/configurator/configurator.c
@@ -319,6 +319,52 @@ static struct test tests[] = {
          "-Werror -fopenmp" },
        { "HAVE_VALGRIND_MEMCHECK_H", OUTSIDE_MAIN, NULL, NULL,
          "#include <valgrind/memcheck.h>\n" },
+       { "HAVE_UCONTEXT", DEFINES_EVERYTHING|EXECUTE,
+         NULL, NULL,
+         "#include <ucontext.h>\n"
+         "static int x = 0;\n"
+         "static char stack[1024];\n"
+         "static ucontext_t a, b;\n"
+         "static void fn(void) {\n"
+         "     x |= 2;\n"
+         "     setcontext(&b);\n"
+         "     x |= 4;\n"
+         "}\n"
+         "int main(int argc, char *argv[]) {\n"
+         "     x |= 1;\n"
+         "     getcontext(&a);\n"
+         "     a.uc_stack.ss_sp = stack;\n"
+         "     a.uc_stack.ss_size = sizeof(stack);\n"
+         "     makecontext(&a, fn, 0);\n"
+         "     swapcontext(&b, &a);\n"
+         "     return (x == 3) ? 0 : 1;\n"
+         "}\n"
+       },
+       { "HAVE_POINTER_SAFE_MAKECONTEXT", DEFINES_EVERYTHING|EXECUTE,
+         "HAVE_UCONTEXT", NULL,
+         "#include <stddef.h>\n"
+         "#include <ucontext.h>\n"
+         "static int worked = 0;\n"
+         "static char stack[1024];\n"
+         "static ucontext_t a, b;\n"
+         "static void fn(void *p, void *q) {\n"
+         "     void *cp = &worked;\n"
+         "     void *cq = (void *)(~((ptrdiff_t)cp));\n"
+         "     if ((p == cp) && (q == cq))\n"
+         "             worked = 1;\n"
+         "     setcontext(&b);\n"
+         "}\n"
+         "int main(int argc, char *argv[]) {\n"
+         "     void *ap = &worked;\n"
+         "     void *aq = (void *)(~((ptrdiff_t)ap));\n"
+         "     getcontext(&a);\n"
+         "     a.uc_stack.ss_sp = stack;\n"
+         "     a.uc_stack.ss_size = sizeof(stack);\n"
+         "     makecontext(&a, (void (*)(void))fn, 2, ap, aq);\n"
+         "     swapcontext(&b, &a);\n"
+         "     return worked ? 0 : 1;\n"
+         "}\n"
+       },
 };
 
 static char *grab_fd(int fd)