nios2: Process management

This patch adds support for thread creation and context switching.

Signed-off-by: Ley Foon Tan <lftan@altera.com>

1 files changed, 120 insertions, 0 deletions

diff --git a/arch/nios2/include/asm/thread_info.h b/arch/nios2/include/asm/thread_info.h
new file mode 100644
index 000000000000..1f266575beb5
--- /dev/null
+++ b/arch/nios2/include/asm/thread_info.h
@@ -0,0 +1,120 @@
+/*
+ * NiosII low-level thread information
+ *
+ * Copyright (C) 2011 Tobias Klauser <tklauser@distanz.ch>
+ * Copyright (C) 2004 Microtronix Datacom Ltd.
+ *
+ * Based on asm/thread_info_no.h from m68k which is:
+ *
+ * Copyright (C) 2002 David Howells <dhowells@redhat.com>
+ *
+ * This file is subject to the terms and conditions of the GNU General Public
+ * License.  See the file "COPYING" in the main directory of this archive
+ * for more details.
+ */
+
+#ifndef _ASM_NIOS2_THREAD_INFO_H
+#define _ASM_NIOS2_THREAD_INFO_H
+
+#ifdef __KERNEL__
+
+/*
+ * Size of the kernel stack for each process.
+ */
+#define THREAD_SIZE_ORDER	1
+#define THREAD_SIZE		8192 /* 2 * PAGE_SIZE */
+
+#ifndef __ASSEMBLY__
+
+typedef struct {
+	unsigned long seg;
+} mm_segment_t;
+
+/*
+ * low level task data that entry.S needs immediate access to
+ * - this struct should fit entirely inside of one cache line
+ * - this struct shares the supervisor stack pages
+ * - if the contents of this structure are changed, the assembly constants
+ *   must also be changed
+ */
+struct thread_info {
+	struct task_struct	*task;		/* main task structure */
+	struct exec_domain	*exec_domain;	/* execution domain */
+	unsigned long		flags;		/* low level flags */
+	__u32			cpu;		/* current CPU */
+	int			preempt_count;	/* 0 => preemptable,<0 => BUG */
+	mm_segment_t		addr_limit;	/* thread address space:
+						  0-0x7FFFFFFF for user-thead
+						  0-0xFFFFFFFF for kernel-thread
+						*/
+	struct restart_block	restart_block;
+	struct pt_regs		*regs;
+};
+
+/*
+ * macros/functions for gaining access to the thread information structure
+ *
+ * preempt_count needs to be 1 initially, until the scheduler is functional.
+ */
+#define INIT_THREAD_INFO(tsk)			\
+{						\
+	.task		= &tsk,			\
+	.exec_domain	= &default_exec_domain,	\
+	.flags		= 0,			\
+	.cpu		= 0,			\
+	.preempt_count	= INIT_PREEMPT_COUNT,	\
+	.addr_limit	= KERNEL_DS,		\
+	.restart_block	= {			\
+		.fn = do_no_restart_syscall,	\
+	},					\
+}
+
+#define init_thread_info	(init_thread_union.thread_info)
+#define init_stack		(init_thread_union.stack)
+
+/* how to get the thread information struct from C */
+static inline struct thread_info *current_thread_info(void)
+{
+	register unsigned long sp asm("sp");
+
+	return (struct thread_info *)(sp & ~(THREAD_SIZE - 1));
+}
+#endif /* !__ASSEMBLY__ */
+
+/*
+ * thread information flags
+ * - these are process state flags that various assembly files may need to
+ *   access
+ * - pending work-to-be-done flags are in LSW
+ * - other flags in MSW
+ */
+#define TIF_SYSCALL_TRACE	0	/* syscall trace active */
+#define TIF_NOTIFY_RESUME	1	/* resumption notification requested */
+#define TIF_SIGPENDING		2	/* signal pending */
+#define TIF_NEED_RESCHED	3	/* rescheduling necessary */
+#define TIF_MEMDIE		4	/* is terminating due to OOM killer */
+#define TIF_SECCOMP		5	/* secure computing */
+#define TIF_SYSCALL_AUDIT	6	/* syscall auditing active */
+#define TIF_RESTORE_SIGMASK	9	/* restore signal mask in do_signal() */
+
+#define TIF_POLLING_NRFLAG	16	/* true if poll_idle() is polling
+					   TIF_NEED_RESCHED */
+
+#define _TIF_SYSCALL_TRACE	(1 << TIF_SYSCALL_TRACE)
+#define _TIF_NOTIFY_RESUME	(1 << TIF_NOTIFY_RESUME)
+#define _TIF_SIGPENDING		(1 << TIF_SIGPENDING)
+#define _TIF_NEED_RESCHED	(1 << TIF_NEED_RESCHED)
+#define _TIF_SECCOMP		(1 << TIF_SECCOMP)
+#define _TIF_SYSCALL_AUDIT	(1 << TIF_SYSCALL_AUDIT)
+#define _TIF_RESTORE_SIGMASK	(1 << TIF_RESTORE_SIGMASK)
+#define _TIF_POLLING_NRFLAG	(1 << TIF_POLLING_NRFLAG)
+
+/* work to do on interrupt/exception return */
+#define _TIF_WORK_MASK		0x0000FFFE
+
+/* work to do on any return to u-space */
+# define _TIF_ALLWORK_MASK	0x0000FFFF
+
+#endif /* __KERNEL__ */
+
+#endif /* _ASM_NIOS2_THREAD_INFO_H */