metag: Scheduling/Process management

Signed-off-by: James Hogan <james.hogan@imgtec.com>

arch/metag/include/asm/thread_info.h

+/* thread_info.h: Meta low-level thread information
+ *
+ * Copyright (C) 2002  David Howells (dhowells@redhat.com)
+ * - Incorporating suggestions made by Linus Torvalds and Dave Miller
+ *
+ * Meta port by Imagination Technologies
+ */
+
+#ifndef _ASM_THREAD_INFO_H
+#define _ASM_THREAD_INFO_H
+
+#include <linux/compiler.h>
+#include <asm/page.h>
+
+#ifndef __ASSEMBLY__
+#include <asm/processor.h>
+#endif
+
+/*
+ * 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
+ */
+#ifndef __ASSEMBLY__
+
+/* This must be 8 byte aligned so we can ensure stack alignment. */
+struct thread_info {
+	struct task_struct *task;	/* main task structure */
+	struct exec_domain *exec_domain;	/* execution domain */
+	unsigned long flags;	/* low level flags */
+	unsigned long status;	/* thread-synchronous flags */
+	u32 cpu;		/* current CPU */
+	int preempt_count;	/* 0 => preemptable, <0 => BUG */
+
+	mm_segment_t addr_limit;	/* thread address space */
+	struct restart_block restart_block;
+
+	u8 supervisor_stack[0];
+};
+
+#else /* !__ASSEMBLY__ */
+
+#include <generated/asm-offsets.h>
+
+#endif
+
+#define PREEMPT_ACTIVE		0x10000000
+
+#ifdef CONFIG_4KSTACKS
+#define THREAD_SHIFT		12
+#else
+#define THREAD_SHIFT		13
+#endif
+
+#if THREAD_SHIFT >= PAGE_SHIFT
+#define THREAD_SIZE_ORDER	(THREAD_SHIFT - PAGE_SHIFT)
+#else
+#define THREAD_SIZE_ORDER	0
+#endif
+
+#define THREAD_SIZE		(PAGE_SIZE << THREAD_SIZE_ORDER)
+
+#define STACK_WARN		(THREAD_SIZE/8)
+/*
+ * macros/functions for gaining access to the thread information structure
+ */
+#ifndef __ASSEMBLY__
+
+#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 current stack pointer from C */
+register unsigned long current_stack_pointer asm("A0StP") __used;
+
+/* how to get the thread information struct from C */
+static inline struct thread_info *current_thread_info(void)
+{
+	return (struct thread_info *)(current_stack_pointer &
+				      ~(THREAD_SIZE - 1));
+}
+
+#define __HAVE_ARCH_KSTACK_END
+static inline int kstack_end(void *addr)
+{
+	return addr == (void *) (((unsigned long) addr & ~(THREAD_SIZE - 1))
+				 + sizeof(struct thread_info));
+}
+
+#endif
+
+/*
+ * 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_SIGPENDING		1	/* signal pending */
+#define TIF_NEED_RESCHED	2	/* rescheduling necessary */
+#define TIF_SINGLESTEP		3	/* restore singlestep on return to user
+					   mode */
+#define TIF_SYSCALL_AUDIT	4	/* syscall auditing active */
+#define TIF_SECCOMP		5	/* secure computing */
+#define TIF_RESTORE_SIGMASK	6	/* restore signal mask in do_signal() */
+#define TIF_NOTIFY_RESUME	7	/* callback before returning to user */
+#define TIF_POLLING_NRFLAG      8	/* true if poll_idle() is polling
+					   TIF_NEED_RESCHED */
+#define TIF_MEMDIE		9	/* is terminating due to OOM killer */
+#define TIF_SYSCALL_TRACEPOINT  10	/* syscall tracepoint instrumentation */
+
+
+#define _TIF_SYSCALL_TRACE	(1<<TIF_SYSCALL_TRACE)
+#define _TIF_SIGPENDING		(1<<TIF_SIGPENDING)
+#define _TIF_NEED_RESCHED	(1<<TIF_NEED_RESCHED)
+#define _TIF_SINGLESTEP		(1<<TIF_SINGLESTEP)
+#define _TIF_SYSCALL_AUDIT	(1<<TIF_SYSCALL_AUDIT)
+#define _TIF_SECCOMP		(1<<TIF_SECCOMP)
+#define _TIF_NOTIFY_RESUME	(1<<TIF_NOTIFY_RESUME)
+#define _TIF_RESTORE_SIGMASK	(1<<TIF_RESTORE_SIGMASK)
+#define _TIF_SYSCALL_TRACEPOINT	(1<<TIF_SYSCALL_TRACEPOINT)
+
+/* work to do in syscall trace */
+#define _TIF_WORK_SYSCALL_MASK	(_TIF_SYSCALL_TRACE | _TIF_SINGLESTEP | \
+				 _TIF_SYSCALL_AUDIT | _TIF_SECCOMP | \
+				 _TIF_SYSCALL_TRACEPOINT)
+
+/* work to do on any return to u-space */
+#define _TIF_ALLWORK_MASK	(_TIF_SYSCALL_TRACE | _TIF_SIGPENDING      | \
+				 _TIF_NEED_RESCHED  | _TIF_SYSCALL_AUDIT   | \
+				 _TIF_SINGLESTEP    | _TIF_RESTORE_SIGMASK | \
+				 _TIF_NOTIFY_RESUME)
+
+/* work to do on interrupt/exception return */
+#define _TIF_WORK_MASK		(_TIF_ALLWORK_MASK & ~(_TIF_SYSCALL_TRACE | \
+				 _TIF_SYSCALL_AUDIT | _TIF_SINGLESTEP))
+
+#define tsk_is_polling(t) test_tsk_thread_flag(t, TIF_POLLING_NRFLAG)
+
+#endif /* _ASM_THREAD_INFO_H */