[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>

3 files changed, 23 insertions, 120 deletions

diff --git a/include/asm-ppc64/thread_info.h b/include/asm-powerpc/thread_info.h
index 71244d8..0b4c245 100644
--- a/include/asm-ppc64/thread_info.h
+++ b/include/asm-powerpc/thread_info.h
@@ -1,15 +1,25 @@
-/* thread_info.h: PPC low-level thread information
+/* 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_THREAD_INFO_H
-#define _ASM_THREAD_INFO_H
+#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>
@@ -24,7 +34,8 @@ 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 */
+	int		preempt_count;		/* 0 => preemptable,
+						   <0 => BUG */
 	struct restart_block restart_block;
 	/* set by force_successful_syscall_return */
 	unsigned char	syscall_noerror;
@@ -54,9 +65,6 @@ struct thread_info {
 
 /* thread information allocation */
 
-#define THREAD_SHIFT		14
-#define THREAD_ORDER		(THREAD_SHIFT - PAGE_SHIFT)
-#define THREAD_SIZE		(1 << THREAD_SHIFT)
 #ifdef CONFIG_DEBUG_STACK_USAGE
 #define alloc_thread_info(tsk)					\
 	({							\
@@ -68,7 +76,7 @@ struct thread_info {
 		ret;						\
 	})
 #else
-#define alloc_thread_info(tsk) kmalloc(THREAD_SIZE, GFP_KERNEL)
+#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)
@@ -77,9 +85,11 @@ struct thread_info {
 /* how to get the thread information struct from C */
 static inline struct thread_info *current_thread_info(void)
 {
-	struct thread_info *ti;
-	__asm__("clrrdi %0,1,%1" : "=r"(ti) : "i" (THREAD_SHIFT));
-	return ti;
+	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__ */
@@ -122,4 +132,4 @@ static inline struct thread_info *current_thread_info(void)
 
 #endif /* __KERNEL__ */
 
-#endif /* _ASM_THREAD_INFO_H */
+#endif /* _ASM_POWERPC_THREAD_INFO_H */
diff --git a/include/asm-ppc/ptrace.h b/include/asm-ppc/ptrace.h
index 7043c16..c34fb4e 100644
--- a/include/asm-ppc/ptrace.h
+++ b/include/asm-ppc/ptrace.h
@@ -57,7 +57,7 @@ extern unsigned long profile_pc(struct pt_regs *regs);
 
 #define force_successful_syscall_return()   \
 	do { \
-		current_thread_info()->local_flags |= _TIFL_FORCE_NOERROR; \
+		current_thread_info()->syscall_noerror = 1; \
 	} while(0)
 
 /*
diff --git a/include/asm-ppc/thread_info.h b/include/asm-ppc/thread_info.h
deleted file mode 100644
index 27903db..0000000
--- a/include/asm-ppc/thread_info.h
+++ /dev/null
@@ -1,107 +0,0 @@
-/* thread_info.h: PPC 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_THREAD_INFO_H
-#define _ASM_THREAD_INFO_H
-
-#ifdef __KERNEL__
-#ifndef __ASSEMBLY__
-/*
- * low level task data.
- * If you change this, change the TI_* offsets below to match.
- */
-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		local_flags;	/* non-racy flags */
-	int			cpu;		/* cpu we're on */
-	int			preempt_count;	/* 0 => preemptable,
-						   <0 => BUG */
-	struct restart_block	restart_block;
-};
-
-#define INIT_THREAD_INFO(tsk)			\
-{						\
-	.task =		&tsk,			\
-	.exec_domain =	&default_exec_domain,	\
-	.flags =	0,			\
-	.local_flags =  0,			\
-	.cpu =		0,			\
-	.preempt_count = 1,			\
-	.restart_block = {			\
-		.fn = do_no_restart_syscall,	\
-	},					\
-}
-
-#define init_thread_info	(init_thread_union.thread_info)
-#define init_stack		(init_thread_union.stack)
-
-/*
- * macros/functions for gaining access to the thread information structure
- */
-
-/* how to get the thread information struct from C */
-static inline struct thread_info *current_thread_info(void)
-{
-	struct thread_info *ti;
-	__asm__("rlwinm %0,1,0,0,18" : "=r"(ti));
-	return ti;
-}
-
-/* thread information allocation */
-#define alloc_thread_info(tsk) ((struct thread_info *) \
-				__get_free_pages(GFP_KERNEL, 1))
-#define free_thread_info(ti)	free_pages((unsigned long) (ti), 1)
-#define get_thread_info(ti)	get_task_struct((ti)->task)
-#define put_thread_info(ti)	put_task_struct((ti)->task)
-#endif /* __ASSEMBLY__ */
-
-/*
- * Size of kernel stack for each process.
- */
-#define THREAD_SIZE		8192	/* 2 pages */
-
-#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_MEMDIE		5
-#define TIF_SYSCALL_AUDIT       6       /* syscall auditing active */
-#define TIF_SECCOMP             7      /* 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_SYSCALL_AUDIT      (1<<TIF_SYSCALL_AUDIT)
-#define _TIF_SECCOMP            (1<<TIF_SECCOMP)
-
-#define _TIF_SYSCALL_T_OR_A     (_TIF_SYSCALL_TRACE|_TIF_SYSCALL_AUDIT|_TIF_SECCOMP)
-
-/*
- * Non racy (local) flags bit numbers
- */
-#define TIFL_FORCE_NOERROR	0	/* don't return error from current
-					   syscall even if result < 0 */
-
-/* as above, but as bit values */
-#define _TIFL_FORCE_NOERROR	(1<<TIFL_FORCE_NOERROR)
-
-
-#endif /* __KERNEL__ */
-
-#endif /* _ASM_THREAD_INFO_H */