kernel: mmap syscall

kernel-src/sys/syscalls/mmap.c

@@ -0,0 +1,58 @@
+#include <kernel/syscalls.h>
+#include <kernel/abi.h>
+#include <errno.h>
+#include <kernel/vmm.h>
+#include <logging.h>
+
+#define PROT_READ  0x01
+#define PROT_WRITE 0x02
+#define PROT_EXEC  0x04
+
+#define MAP_SHARED    0x01
+#define MAP_PRIVATE   0x02
+#define MAP_FIXED     0x10
+#define MAP_ANON      0x20
+#define MAP_ANONYMOUS MAP_ANON
+
+#define KNOWN_PROT (PROT_READ | PROT_WRITE | PROT_EXEC)
+#define KNOWN_FLAGS (MAP_SHARED | MAP_PRIVATE | MAP_FIXED | MAP_ANONYMOUS)
+
+syscallret_t syscall_mmap(context_t *context, void *hint, size_t len, int prot, int flags, int fd, off_t offset) {
+	syscallret_t ret = {
+		.errno = 0,
+		.ret = -1
+	};
+
+	__assert((~KNOWN_FLAGS & flags) == 0);
+	__assert((~KNOWN_PROT & prot) == 0);
+
+	// check alignment
+	if (len == 0 || (uintptr_t)hint % PAGE_SIZE || len % PAGE_SIZE) {
+		ret.errno = EINVAL;
+		return ret;
+	}
+
+	mmuflags_t mmuflags = ARCH_MMU_FLAGS_USER;
+	if (prot & PROT_READ)
+		mmuflags |= ARCH_MMU_FLAGS_READ;
+	if (prot & PROT_WRITE)
+		mmuflags |= ARCH_MMU_FLAGS_WRITE;
+	if ((prot & PROT_EXEC) == 0)
+		mmuflags |= ARCH_MMU_FLAGS_NOEXEC;
+
+	bool file = (flags & MAP_ANONYMOUS) == 0;
+	// TODO MAP_FIXED
+	__assert((flags & MAP_FIXED) == 0);
+	int vmmflags = 0;
+	vmmfiledesc_t vfd;
+	// TODO file mappings
+	__assert(file == false);
+
+	if (hint < USERSPACE_START)
+		hint = USERSPACE_START;
+
+	ret.ret = (uint64_t)vmm_map(hint, len, vmmflags, mmuflags, &vfd);
+	if (ret.ret == 0)
+		ret.errno = ENOMEM;
+	return ret;
+}