[PATCH] powerpc: Merge thread_info.h

Merge ppc32 and ppc64 versions of thread_info.h.  They were pretty
similar already, the chief changes are:

	- Instead of inline asm to implement current_thread_info(),
which needs to be different for ppc32 and ppc64, we use C with an
asm("r1") register variable.  gcc turns it into the same asm as we
used to have for both platforms.
	- We replace ppc32's 'local_flags' with the ppc64
'syscall_noerror' field.  The noerror flag was in fact the only thing
in the local_flags field anyway, so the ppc64 approach is simpler, and
means we only need a load-immediate/store instead of load/mask/store
when clearing the flag.
	- In readiness for 64k pages, when THREAD_SIZE will be less
than a page, ppc64 used kmalloc() rather than get_free_pages() to
allocate the kernel stack.  With this patch we do the same for ppc32,
since there's no strong reason not to.
	- For ppc64, we no longer export THREAD_SHIFT and THREAD_SIZE
via asm-offsets, thread_info.h can now be safely included in asm, as
on ppc32.

Built and booted on G4 Powerbook (ARCH=ppc and ARCH=powerpc) and
Power5 (ARCH=ppc64 and ARCH=powerpc).

Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Paul Mackerras <paulus@samba.org>

1 files changed, 135 insertions, 0 deletions

diff --git a/include/asm-powerpc/thread_info.h b/include/asm-powerpc/thread_info.h
new file mode 100644
index 000000000000..0b4c24551c21
--- /dev/null
+++ b/include/asm-powerpc/thread_info.h
@@ -0,0 +1,135 @@
+/* thread_info.h: PowerPC low-level thread information
+ * adapted from the i386 version by Paul Mackerras
+ *
+ * Copyright (C) 2002  David Howells (dhowells@redhat.com)
+ * - Incorporating suggestions made by Linus Torvalds and Dave Miller
+ */
+
+#ifndef _ASM_POWERPC_THREAD_INFO_H
+#define _ASM_POWERPC_THREAD_INFO_H
+
+#ifdef __KERNEL__
+
+/* We have 8k stacks on ppc32 and 16k on ppc64 */
+
+#ifdef CONFIG_PPC64
+#define THREAD_SHIFT		14
+#else
+#define THREAD_SHIFT		13
+#endif
+
+#define THREAD_SIZE		(1 << THREAD_SHIFT)
+
+#ifndef __ASSEMBLY__
+#include <linux/config.h>
+#include <linux/cache.h>
+#include <asm/processor.h>
+#include <asm/page.h>
+#include <linux/stringify.h>
+
+/*
+ * low level task data.
+ */
+struct thread_info {
+	struct task_struct *task;		/* main task structure */
+	struct exec_domain *exec_domain;	/* execution domain */
+	int		cpu;			/* cpu we're on */
+	int		preempt_count;		/* 0 => preemptable,
+						   <0 => BUG */
+	struct restart_block restart_block;
+	/* set by force_successful_syscall_return */
+	unsigned char	syscall_noerror;
+	/* low level flags - has atomic operations done on it */
+	unsigned long	flags ____cacheline_aligned_in_smp;
+};
+
+/*
+ * 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,	\
+	.cpu =		0,			\
+	.preempt_count = 1,			\
+	.restart_block = {			\
+		.fn = do_no_restart_syscall,	\
+	},					\
+	.flags =	0,			\
+}
+
+#define init_thread_info	(init_thread_union.thread_info)
+#define init_stack		(init_thread_union.stack)
+
+/* thread information allocation */
+
+#ifdef CONFIG_DEBUG_STACK_USAGE
+#define alloc_thread_info(tsk)					\
+	({							\
+		struct thread_info *ret;			\
+								\
+		ret = kmalloc(THREAD_SIZE, GFP_KERNEL);		\
+		if (ret)					\
+			memset(ret, 0, THREAD_SIZE);		\
+		ret;						\
+	})
+#else
+#define alloc_thread_info(tsk)	kmalloc(THREAD_SIZE, GFP_KERNEL)
+#endif
+#define free_thread_info(ti)	kfree(ti)
+#define get_thread_info(ti)	get_task_struct((ti)->task)
+#define put_thread_info(ti)	put_task_struct((ti)->task)
+
+/* how to get the thread information struct from C */
+static inline struct thread_info *current_thread_info(void)
+{
+	register unsigned long sp asm("r1");
+
+	/* gcc4, at least, is smart enough to turn this into a single
+	 * rlwinm for ppc32 and clrrdi for ppc64 */
+	return (struct thread_info *)(sp & ~(THREAD_SIZE-1));
+}
+
+#endif /* __ASSEMBLY__ */
+
+#define PREEMPT_ACTIVE		0x10000000
+
+/*
+ * thread information flag bit numbers
+ */
+#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_POLLING_NRFLAG	4	/* true if poll_idle() is polling
+					   TIF_NEED_RESCHED */
+#define TIF_32BIT		5	/* 32 bit binary */
+/* #define SPARE		6 */
+#define TIF_ABI_PENDING		7	/* 32/64 bit switch needed */
+#define TIF_SYSCALL_AUDIT	8	/* syscall auditing active */
+#define TIF_SINGLESTEP		9	/* singlestepping active */
+#define TIF_MEMDIE		10
+#define TIF_SECCOMP		11	/* secure computing */
+
+/* as above, but as bit values */
+#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_POLLING_NRFLAG	(1<<TIF_POLLING_NRFLAG)
+#define _TIF_32BIT		(1<<TIF_32BIT)
+/* #define _SPARE		(1<<SPARE) */
+#define _TIF_ABI_PENDING	(1<<TIF_ABI_PENDING)
+#define _TIF_SYSCALL_AUDIT	(1<<TIF_SYSCALL_AUDIT)
+#define _TIF_SINGLESTEP		(1<<TIF_SINGLESTEP)
+#define _TIF_SECCOMP		(1<<TIF_SECCOMP)
+#define _TIF_SYSCALL_T_OR_A	(_TIF_SYSCALL_TRACE|_TIF_SYSCALL_AUDIT|_TIF_SECCOMP)
+
+#define _TIF_USER_WORK_MASK	(_TIF_NOTIFY_RESUME | _TIF_SIGPENDING | \
+				 _TIF_NEED_RESCHED)
+
+#endif /* __KERNEL__ */
+
+#endif /* _ASM_POWERPC_THREAD_INFO_H */