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-rw-r--r--erts/emulator/sys/common/erl_mseg.c56
1 files changed, 54 insertions, 2 deletions
diff --git a/erts/emulator/sys/common/erl_mseg.c b/erts/emulator/sys/common/erl_mseg.c
index f4e21bc05f..c859b192f7 100644
--- a/erts/emulator/sys/common/erl_mseg.c
+++ b/erts/emulator/sys/common/erl_mseg.c
@@ -87,11 +87,22 @@ static int is_cache_check_requested;
/* Mmap ... */
#define MMAP_PROT (PROT_READ|PROT_WRITE)
+
+#if HALFWORD_HEAP
+# ifdef MAP_32BIT
+# define RANGE_FLAG (MAP_32BIT)
+# else
+# error "Cannot have halfword heap if unable to restrict mmap areas
+# endif
+#else
+# define RANGE_FLAG (0)
+#endif
+
#ifdef MAP_ANON
-# define MMAP_FLAGS (MAP_ANON|MAP_PRIVATE)
+# define MMAP_FLAGS (MAP_ANON|MAP_PRIVATE|RANGE_FLAG)
# define MMAP_FD (-1)
#else
-# define MMAP_FLAGS (MAP_PRIVATE)
+# define MMAP_FLAGS (MAP_PRIVATE|RANGE_FLAG)
# define MMAP_FD mmap_fd
static int mmap_fd;
#endif
@@ -310,6 +321,12 @@ mseg_create(Uint size)
MMAP_PROT, MMAP_FLAGS, MMAP_FD, 0);
if (seg == (void *) MAP_FAILED)
seg = NULL;
+#if HALFWORD_HEAP
+ if ((unsigned long) seg & CHECK_POINTER_MASK) {
+ erts_fprintf(stderr,"Pointer mask failure (0x%08lx)\n",(unsigned long) seg);
+ return NULL;
+ }
+#endif
#else
#error "Missing mseg_create() implementation"
#endif
@@ -1300,6 +1317,37 @@ erts_mseg_unit_size(void)
{
return page_size;
}
+#if HAVE_MMAP && HALFWORD_HEAP
+#ifdef MAP_NORESERVE
+#define RESERVE_FLAGS (MMAP_FLAGS | MAP_NORESERVE)
+#else
+#define RESERVE_FLAGS (MMAP_FLAGS)
+#endif
+static void halfword_reserve(void)
+{
+#if 0
+ void *ptr, *understack;
+ unsigned long x = 0x80000000;
+ long i = 0;
+
+ understack = mmap(NULL,GET_PAGE_SIZE, PROT_NONE, RESERVE_FLAGS,
+ MMAP_FD, 0);
+ while (x < (unsigned long) understack) {
+ ptr = mmap((void *) x, GET_PAGE_SIZE, PROT_NONE, RESERVE_FLAGS,
+ MMAP_FD, 0);
+ if ((unsigned long) ptr < 0x80000000) {
+ munmap(ptr, GET_PAGE_SIZE);
+ } else {
+ ++i;
+ }
+ x += GET_PAGE_SIZE;
+ }
+ erts_fprintf(stderr,"Reserved %ld pages [%d MB]...\n",i, (i*GET_PAGE_SIZE)/1024/1024);
+#else
+ return;
+#endif
+}
+#endif
void
erts_mseg_init(ErtsMsegInit_t *init)
@@ -1328,6 +1376,10 @@ erts_mseg_init(ErtsMsegInit_t *init)
erl_exit(ERTS_ABORT_EXIT, "erts_mseg: unable to open /dev/zero\n");
#endif
+#if HAVE_MMAP && HALFWORD_HEAP
+ halfword_reserve();
+#endif
+
page_size = GET_PAGE_SIZE;
page_shift = 1;