1 files changed, 113 insertions, 0 deletions
diff --git a/src/pkg/runtime/linux/mem.c b/src/pkg/runtime/linux/mem.c
new file mode 100644
index 000000000..ad0fac6d3
--- /dev/null
+++ b/src/pkg/runtime/linux/mem.c
@@ -0,0 +1,113 @@
+#include "runtime.h"
+#include "defs.h"
+#include "os.h"
+#include "malloc.h"
+
+enum
+{
+	ENOMEM = 12,
+};
+
+static int32
+addrspace_free(void *v, uintptr n)
+{
+	uintptr page_size = 4096;
+	uintptr off;
+	int8 one_byte;
+
+	for(off = 0; off < n; off += page_size) {
+		int32 errval = runtime·mincore((int8 *)v + off, page_size, (void *)&one_byte);
+		// errval is 0 if success, or -(error_code) if error.
+		if (errval == 0 || errval != -ENOMEM)
+			return 0;
+	}
+	USED(v);
+	USED(n);
+	return 1;
+}
+
+
+void*
+runtime·SysAlloc(uintptr n)
+{
+	void *p;
+
+	mstats.sys += n;
+	p = runtime·mmap(nil, n, PROT_READ|PROT_WRITE|PROT_EXEC, MAP_ANON|MAP_PRIVATE, -1, 0);
+	if(p < (void*)4096) {
+		if(p == (void*)EACCES) {
+			runtime·printf("runtime: mmap: access denied\n");
+			runtime·printf("if you're running SELinux, enable execmem for this process.\n");
+			runtime·exit(2);
+		}
+		return nil;
+	}
+	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·SysReserve(void *v, uintptr n)
+{
+	void *p;
+
+	// On 64-bit, people with ulimit -v set complain if we reserve too
+	// much address space.  Instead, assume that the reservation is okay
+	// and check the assumption in SysMap.
+	if(sizeof(void*) == 8)
+		return v;
+	
+	p = runtime·mmap(v, n, PROT_NONE, MAP_ANON|MAP_PRIVATE, -1, 0);
+	if(p < (void*)4096) {
+		return nil;
+	}
+	return p;
+}
+
+void
+runtime·SysMap(void *v, uintptr n)
+{
+	void *p;
+	
+	mstats.sys += n;
+
+	// On 64-bit, we don't actually have v reserved, so tread carefully.
+	if(sizeof(void*) == 8) {
+		p = runtime·mmap(v, n, PROT_READ|PROT_WRITE|PROT_EXEC, MAP_ANON|MAP_PRIVATE, -1, 0);
+		if(p != v && addrspace_free(v, n)) {
+			// On some systems, mmap ignores v without
+			// MAP_FIXED, so retry if the address space is free.
+			if(p > (void*)4096) {
+				runtime·munmap(p, n);
+			}
+			p = runtime·mmap(v, n, PROT_READ|PROT_WRITE|PROT_EXEC, MAP_ANON|MAP_FIXED|MAP_PRIVATE, -1, 0);
+		}
+		if(p == (void*)ENOMEM)
+			runtime·throw("runtime: out of memory");
+		if(p != v) {
+			runtime·printf("runtime: address space conflict: map(%p) = %p\n", v, p);
+			runtime·throw("runtime: address space conflict");
+		}
+		return;
+	}
+
+	p = runtime·mmap(v, n, PROT_READ|PROT_WRITE|PROT_EXEC, MAP_ANON|MAP_FIXED|MAP_PRIVATE, -1, 0);
+	if(p == (void*)ENOMEM)
+		runtime·throw("runtime: out of memory");
+	if(p != v)
+		runtime·throw("runtime: cannot map pages in arena address space");
+}