1 files changed, 76 insertions, 0 deletions
diff --git a/libgo/runtime/mem.c b/libgo/runtime/mem.c
new file mode 100644
index 000000000..4d6c74209
--- /dev/null
+++ b/libgo/runtime/mem.c
@@ -0,0 +1,76 @@
+#include <errno.h>
+
+#include "runtime.h"
+#include "malloc.h"
+
+#ifndef MAP_ANON
+#ifdef MAP_ANONYMOUS
+#define MAP_ANON MAP_ANONYMOUS
+#else
+#define USE_DEV_ZERO
+#define MAP_ANON 0
+#endif
+#endif
+
+#ifdef USE_DEV_ZERO
+static int dev_zero = -1;
+#endif
+
+void*
+runtime_SysAlloc(uintptr n)
+{
+	void *p;
+	int fd = -1;
+
+	mstats.sys += n;
+
+#ifdef USE_DEV_ZERO
+	if (dev_zero == -1) {
+		dev_zero = open("/dev/zero", O_RDONLY);
+		if (dev_zero < 0) {
+			printf("open /dev/zero: errno=%d\n", errno);
+			exit(2);
+		}
+	}
+	fd = dev_zero;
+#endif
+
+	p = runtime_mmap(nil, n, PROT_READ|PROT_WRITE|PROT_EXEC, MAP_ANON|MAP_PRIVATE, fd, 0);
+	if (p == MAP_FAILED) {
+		if(errno == EACCES) {
+			printf("mmap: access denied\n");
+			printf("If you're running SELinux, enable execmem for this process.\n");
+		} else {
+			printf("mmap: errno=%d\n", errno);
+		}
+		exit(2);
+	}
+	return p;
+}
+
+void
+runtime_SysUnused(void *v, uintptr n)
+{
+	USED(v);
+	USED(n);
+	// TODO(rsc): call madvise MADV_DONTNEED
+}
+
+void
+runtime_SysFree(void *v, uintptr n)
+{
+	mstats.sys -= n;
+	runtime_munmap(v, n);
+}
+
+void
+runtime_SysMemInit(void)
+{
+	// Code generators assume that references to addresses
+	// on the first page will fault.  Map the page explicitly with
+	// no permissions, to head off possible bugs like the system
+	// allocating that page as the virtual address space fills.
+	// Ignore any error, since other systems might be smart
+	// enough to never allow anything there.
+	runtime_mmap(nil, 4096, PROT_NONE, MAP_FIXED|MAP_ANON|MAP_PRIVATE, -1, 0);
+}