Initial commit

tasks/libl4/include/l4lib/arch-arm/syslib.h

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+/*
+ * Helper functions that wrap raw l4 syscalls.
+ *
+ * Copyright (C) 2007 Bahadir Balban
+ */
+
+#ifndef __L4LIB_SYSLIB_H__
+#define __L4LIB_SYSLIB_H__
+
+#include <stdio.h>
+#include <l4lib/arch/syscalls.h>
+#include <l4/macros.h>
+
+/*
+ * NOTE:
+ * Its best to use these wrappers because they generalise the way
+ * common ipc data like sender id, error, ipc tag are passed
+ * between ipc parties.
+ *
+ * The arguments to l4_ipc() are used by the microkernel to initiate
+ * the ipc. Any data passed in message registers may or may not be
+ * a duplicate of this data, but the distinction is that anything
+ * that is passed via the mrs are meant to be used by the other party
+ * participating in the ipc.
+ */
+
+/* For system call arguments */
+#define L4SYS_ARG0	(MR_UNUSED_START)
+#define	L4SYS_ARG1	(MR_UNUSED_START + 1)
+#define L4SYS_ARG2	(MR_UNUSED_START + 2)
+
+/*
+ * Servers get sender.
+ */
+static inline l4id_t l4_get_sender(void)
+{
+	return (l4id_t)read_mr(MR_SENDER);
+}
+
+static inline void l4_set_sender(l4id_t id)
+{
+	write_mr(MR_SENDER, (unsigned int)id);
+}
+
+static inline unsigned int l4_get_tag(void)
+{
+	return read_mr(MR_TAG);
+}
+
+static inline void l4_set_tag(unsigned int tag)
+{
+	write_mr(MR_TAG, tag);
+}
+
+static inline l4id_t self_tid(void)
+{
+	struct task_ids ids;
+
+	l4_getid(&ids);
+	return ids.tid;
+}
+
+static inline int l4_send(l4id_t to, unsigned int tag)
+{
+	l4_set_tag(tag);
+	l4_set_sender(self_tid());
+	return l4_ipc(to, L4_NILTHREAD, 0);
+}
+
+static inline int l4_sendrecv(l4id_t to, l4id_t from, unsigned int tag)
+{
+	BUG_ON(to == L4_NILTHREAD || from == L4_NILTHREAD);
+	l4_set_tag(tag);
+	l4_set_sender(self_tid());
+	return l4_ipc(to, from, 0);
+}
+
+static inline int l4_receive(l4id_t from)
+{
+	return l4_ipc(L4_NILTHREAD, from, 0);
+}
+
+/* Servers:
+ * Sets the message register for returning errors back to client task.
+ * These are usually posix error codes.
+ */
+static inline void l4_set_retval(int retval)
+{
+	write_mr(MR_RETURN, retval);
+}
+
+/* Clients:
+ * Learn result of request.
+ */ 
+static inline int l4_get_retval(void)
+{
+	return read_mr(MR_RETURN);
+}
+
+/* Servers:
+ * Return the ipc result back to requesting task. 
+ */
+static inline int l4_ipc_return(int retval)
+{
+	unsigned int tag = l4_get_tag();
+	l4id_t sender = l4_get_sender();
+
+	l4_set_retval(retval);
+	return l4_send(sender, tag);
+}
+
+/* A helper that translates and maps a physical address to virtual */
+static inline void *l4_map_helper(void *phys, int npages)
+{
+	struct task_ids ids;
+
+	l4_getid(&ids);
+	l4_map(phys, phys_to_virt(phys), npages, MAP_USR_RW_FLAGS, ids.tid);
+	return phys_to_virt(phys);
+}
+
+
+/* A helper that translates and maps a physical address to virtual */
+static inline void *l4_unmap_helper(void *virt, int npages)
+{
+	struct task_ids ids;
+
+	l4_getid(&ids);
+	l4_unmap(virt, npages, ids.tid);
+	return virt_to_phys(virt);
+}
+
+/*
+ * A helper to produce grant ipc between a pager and its client, or a
+ * synchronous syscall to the kernel in case the grant is to the kernel.
+ */
+static inline int l4_grant_pages(unsigned long pfn, int npages, l4id_t tid)
+{
+	/* Only a pager can grant pages to kernel. */
+	if (tid == KERNEL_TID) {
+		/* Granting physical pages via a system call in kernel case. */
+		return l4_kmem_grant(pfn, npages);
+	} else {
+		/*
+		 * FIXME: This should set up appropriate message registers and
+		 * call l4_ipc() on the target thread. Pages given are virtual.
+		 */
+		while(1);
+	}
+	return 0;
+}
+
+/*
+ * NOTE: This is just brainstroming yet.
+ * A helper to reclaim unused pages. A pager can reclaim pages from kernel or
+ * other tasks this way.
+ */
+static inline int l4_reclaim_pages(l4id_t tid)
+{
+	unsigned long pfn;
+	int npages;
+
+	if (tid == KERNEL_TID) {
+		/*
+		 * A single contiguous sequence of physical pages are returned
+		 * by kernel via a syscall. Simpler the better for now.
+		 */
+		l4_kmem_reclaim(&pfn, &npages);
+	} else {
+		/*
+		 * An ipc to a task where pfn and npages come in message regs.
+		 */
+		while(1);
+	}
+	return 0;
+}
+
+
+#endif /* __L4LIB_SYSLIB_H__ */