[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: NDavid Gibson <david@gibson.dropbear.id.au>
Signed-off-by: NPaul Mackerras <paulus@samba.org>

arch/powerpc/kernel/asm-offsets.c

@@ -56,8 +56,6 @@ int main(void)
 	DEFINE(THREAD, offsetof(struct task_struct, thread));
 	DEFINE(MM, offsetof(struct task_struct, mm));
 #ifdef CONFIG_PPC64
-	DEFINE(THREAD_SHIFT, THREAD_SHIFT);
-	DEFINE(THREAD_SIZE, THREAD_SIZE);
 	DEFINE(AUDITCONTEXT, offsetof(struct task_struct, audit_context));
 #else
 	DEFINE(THREAD_INFO, offsetof(struct task_struct, thread_info));
@@ -94,12 +92,10 @@ int main(void)
 
 	DEFINE(TI_FLAGS, offsetof(struct thread_info, flags));
 	DEFINE(TI_PREEMPT, offsetof(struct thread_info, preempt_count));
-#ifdef CONFIG_PPC64
 	DEFINE(TI_SC_NOERR, offsetof(struct thread_info, syscall_noerror));
-#else
+#ifdef CONFIG_PPC32
 	DEFINE(TI_TASK, offsetof(struct thread_info, task));
 	DEFINE(TI_EXECDOMAIN, offsetof(struct thread_info, exec_domain));
-	DEFINE(TI_LOCAL_FLAGS, offsetof(struct thread_info, local_flags));
 	DEFINE(TI_CPU, offsetof(struct thread_info, cpu));
 #endif /* CONFIG_PPC64 */
 

arch/powerpc/kernel/entry_32.S

@@ -199,10 +199,9 @@ _GLOBAL(DoSyscall)
 #ifdef SHOW_SYSCALLS
 	bl	do_show_syscall
 #endif /* SHOW_SYSCALLS */
-	rlwinm	r10,r1,0,0,18	/* current_thread_info() */
-	lwz	r11,TI_LOCAL_FLAGS(r10)
-	rlwinm	r11,r11,0,~_TIFL_FORCE_NOERROR
-	stw	r11,TI_LOCAL_FLAGS(r10)
+	rlwinm	r10,r1,0,0,(31-THREAD_SHIFT)	/* current_thread_info() */
+	li	r11,0
+	stb	r11,TI_SC_NOERR(r10)
 	lwz	r11,TI_FLAGS(r10)
 	andi.	r11,r11,_TIF_SYSCALL_T_OR_A
 	bne-	syscall_dotrace
@@ -225,10 +224,10 @@ ret_from_syscall:
 	mr	r6,r3
 	li	r11,-_LAST_ERRNO
 	cmplw	0,r3,r11
-	rlwinm	r12,r1,0,0,18	/* current_thread_info() */
+	rlwinm	r12,r1,0,0,(31-THREAD_SHIFT)	/* current_thread_info() */
 	blt+	30f
-	lwz	r11,TI_LOCAL_FLAGS(r12)
-	andi.	r11,r11,_TIFL_FORCE_NOERROR
+	lbz	r11,TI_SC_NOERR(r12)
+	cmpwi	r11,0
 	bne	30f
 	neg	r3,r3
 	lwz	r10,_CCR(r1)	/* Set SO bit in CR */
@@ -315,7 +314,7 @@ syscall_exit_work:
 	LOAD_MSR_KERNEL(r10,MSR_KERNEL)	/* doesn't include MSR_EE */
 	SYNC
 	MTMSRD(r10)		/* disable interrupts again */
-	rlwinm	r12,r1,0,0,18	/* current_thread_info() */
+	rlwinm	r12,r1,0,0,(31-THREAD_SHIFT)	/* current_thread_info() */
 	lwz	r9,TI_FLAGS(r12)
 5:
 	andi.	r0,r9,_TIF_NEED_RESCHED
@@ -630,7 +629,7 @@ END_FTR_SECTION_IFSET(CPU_FTR_601)
 	.globl	sigreturn_exit
 sigreturn_exit:
 	subi	r1,r3,STACK_FRAME_OVERHEAD
-	rlwinm	r12,r1,0,0,18	/* current_thread_info() */
+	rlwinm	r12,r1,0,0,(31-THREAD_SHIFT)	/* current_thread_info() */
 	lwz	r9,TI_FLAGS(r12)
 	andi.	r0,r9,_TIF_SYSCALL_T_OR_A
 	beq+	ret_from_except_full
@@ -657,7 +656,7 @@ ret_from_except:
 
 user_exc_return:		/* r10 contains MSR_KERNEL here */
 	/* Check current_thread_info()->flags */
-	rlwinm	r9,r1,0,0,18
+	rlwinm	r9,r1,0,0,(31-THREAD_SHIFT)
 	lwz	r9,TI_FLAGS(r9)
 	andi.	r0,r9,(_TIF_SIGPENDING|_TIF_NEED_RESCHED)
 	bne	do_work
@@ -677,7 +676,7 @@ restore_user:
 /* N.B. the only way to get here is from the beq following ret_from_except. */
 resume_kernel:
 	/* check current_thread_info->preempt_count */
-	rlwinm	r9,r1,0,0,18
+	rlwinm	r9,r1,0,0,(31-THREAD_SHIFT)
 	lwz	r0,TI_PREEMPT(r9)
 	cmpwi	0,r0,0		/* if non-zero, just restore regs and return */
 	bne	restore
@@ -687,7 +686,7 @@ resume_kernel:
 	andi.	r0,r3,MSR_EE	/* interrupts off? */
 	beq	restore		/* don't schedule if so */
 1:	bl	preempt_schedule_irq
-	rlwinm	r9,r1,0,0,18
+	rlwinm	r9,r1,0,0,(31-THREAD_SHIFT)
 	lwz	r3,TI_FLAGS(r9)
 	andi.	r0,r3,_TIF_NEED_RESCHED
 	bne-	1b
@@ -889,7 +888,7 @@ recheck:
 	LOAD_MSR_KERNEL(r10,MSR_KERNEL)
 	SYNC
 	MTMSRD(r10)		/* disable interrupts */
-	rlwinm	r9,r1,0,0,18
+	rlwinm	r9,r1,0,0,(31-THREAD_SHIFT)
 	lwz	r9,TI_FLAGS(r9)
 	andi.	r0,r9,_TIF_NEED_RESCHED
 	bne-	do_resched

arch/powerpc/kernel/head_64.S

@@ -36,6 +36,7 @@
 #include <asm/setup.h>
 #include <asm/hvcall.h>
 #include <asm/iSeries/LparMap.h>
+#include <asm/thread_info.h>
 
 #ifdef CONFIG_PPC_ISERIES
 #define DO_SOFT_DISABLE

arch/powerpc/kernel/misc_64.S

@@ -26,6 +26,7 @@
 #include <asm/ppc_asm.h>
 #include <asm/asm-offsets.h>
 #include <asm/cputable.h>
+#include <asm/thread_info.h>
 
 	.text
 

arch/ppc/kernel/asm-offsets.c

@@ -130,10 +130,10 @@ main(void)
 	DEFINE(CPU_SPEC_FEATURES, offsetof(struct cpu_spec, cpu_features));
 	DEFINE(CPU_SPEC_SETUP, offsetof(struct cpu_spec, cpu_setup));
 
+	DEFINE(TI_SC_NOERR, offsetof(struct thread_info, syscall_noerror));
 	DEFINE(TI_TASK, offsetof(struct thread_info, task));
 	DEFINE(TI_EXECDOMAIN, offsetof(struct thread_info, exec_domain));
 	DEFINE(TI_FLAGS, offsetof(struct thread_info, flags));
-	DEFINE(TI_LOCAL_FLAGS, offsetof(struct thread_info, local_flags));
 	DEFINE(TI_CPU, offsetof(struct thread_info, cpu));
 	DEFINE(TI_PREEMPT, offsetof(struct thread_info, preempt_count));
 

arch/ppc/kernel/entry.S

@@ -200,9 +200,8 @@ _GLOBAL(DoSyscall)
 	bl	do_show_syscall
 #endif /* SHOW_SYSCALLS */
 	rlwinm	r10,r1,0,0,18	/* current_thread_info() */
-	lwz	r11,TI_LOCAL_FLAGS(r10)
-	rlwinm	r11,r11,0,~_TIFL_FORCE_NOERROR
-	stw	r11,TI_LOCAL_FLAGS(r10)
+	li	r11,0
+	stb	r11,TI_SC_NOERR(r10)
 	lwz	r11,TI_FLAGS(r10)
 	andi.	r11,r11,_TIF_SYSCALL_T_OR_A
 	bne-	syscall_dotrace
@@ -227,8 +226,8 @@ ret_from_syscall:
 	cmplw	0,r3,r11
 	rlwinm	r12,r1,0,0,18	/* current_thread_info() */
 	blt+	30f
-	lwz	r11,TI_LOCAL_FLAGS(r12)
-	andi.	r11,r11,_TIFL_FORCE_NOERROR
+	lbz	r11,TI_SC_NOERR(r12)
+	cmpwi	r11,0
 	bne	30f
 	neg	r3,r3
 	lwz	r10,_CCR(r1)	/* Set SO bit in CR */

arch/ppc64/kernel/asm-offsets.c

@@ -46,8 +46,6 @@
 int main(void)
 {
 	/* thread struct on stack */
-	DEFINE(THREAD_SHIFT, THREAD_SHIFT);
-	DEFINE(THREAD_SIZE, THREAD_SIZE);
 	DEFINE(TI_FLAGS, offsetof(struct thread_info, flags));
 	DEFINE(TI_PREEMPT, offsetof(struct thread_info, preempt_count));
 	DEFINE(TI_SC_NOERR, offsetof(struct thread_info, syscall_noerror));

arch/ppc64/kernel/head.S

@@ -36,6 +36,7 @@
 #include <asm/setup.h>
 #include <asm/hvcall.h>
 #include <asm/iSeries/LparMap.h>
+#include <asm/thread_info.h>
 
 #ifdef CONFIG_PPC_ISERIES
 #define DO_SOFT_DISABLE

arch/ppc64/kernel/misc.S

@@ -28,6 +28,7 @@
 #include <asm/ppc_asm.h>
 #include <asm/asm-offsets.h>
 #include <asm/cputable.h>
+#include <asm/thread_info.h>
 
 	.text
 

include/asm-ppc64/thread_info.h → include/asm-powerpc/thread_info.h

-/* 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 */

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)
 
 /*

include/asm-ppc/thread_info.h

-/* 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 */