ARM preempt and scheduler fixups for 2.5.5

arch/arm/kernel/entry-armv.S

@@ -734,19 +734,22 @@ preempt_return:
 		ldmia	sp, {r0 - pc}^			@ load r0 - pc, cpsr
 
 #ifdef CONFIG_PREEMPT
-svc_preempt:	teq	r9, #0
-		movne	pc, lr
+svc_preempt:	teq	r9, #0				@ was preempt count = 0
+		movne	pc, lr				@ no
 		ldr	r0, [r6, #4]			@ local_irq_count
-		ldr	r1, [r6, #8]			@ local_b_count
+		ldr	r1, [r6, #8]			@ local_bh_count
 		adds	r0, r0, r1
 		movne	pc, lr
-1:		set_cpsr_c r0, #MODE_SVC		@ enable IRQs
-		bl	SYMBOL_NAME(preempt_schedule)
+		ldr	r1, [r8, #TI_TASK]
+		set_cpsr_c r2, #MODE_SVC		@ enable IRQs
+		str	r0, [r1, #0]			@ current->state = TASK_RUNNING
+1:		bl	SYMBOL_NAME(schedule)
 		set_cpsr_c r0, #PSR_I_BIT | MODE_SVC	@ disable IRQs
 		ldr	r0, [r8, #TI_FLAGS]
 		tst	r0, #_TIF_NEED_RESCHED
-		bne	1b
-		b	preempt_return
+		beq	preempt_return
+		set_cpsr_c r0, #MODE_SVC		@ enable IRQs
+		b	1b
 #endif
 
 		.align	5

arch/arm/kernel/entry-common.S

@@ -55,7 +55,7 @@ work_resched:
  */
 ENTRY(ret_to_user)
 ret_slow_syscall:
-	set_cpsr_c r1, #PSR_I_BIT | MODE_SVC
+	set_cpsr_c r1, #PSR_I_BIT | MODE_SVC	@ disable interrupts
 	ldr	r1, [tsk, #TI_FLAGS]
 	tst	r1, #_TIF_WORK_MASK
 	beq	no_work_pending
@@ -73,12 +73,9 @@ __do_notify_resume:
 	b	SYMBOL_NAME(do_notify_resume)	@ note the bl above sets lr
 
 /*
- * This is how we return from a fork.  __switch_to will be calling us
- * with r0 pointing at the previous task that was running (ready for
- * calling schedule_tail).
+ * This is how we return from a fork.
  */
 ENTRY(ret_from_fork)
-	bl	SYMBOL_NAME(schedule_tail)
 	get_thread_info tsk
 	ldr	ip, [tsk, #TI_FLAGS]		@ check for syscall tracing
 	mov	why, #1

arch/arm/kernel/head.S

@@ -127,7 +127,7 @@ __entry:
 		mov	r1, #MACH_TYPE_L7200
 #endif
 
-		mov	r0, #F_BIT | I_BIT | MODE_SVC	@ make sure svc mode
+		mov	r0, #PSR_F_BIT | PSR_I_BIT | MODE_SVC	@ make sure svc mode
 		msr	cpsr_c, r0			@ and all irqs disabled
 		bl	__lookup_processor_type
 		teq	r10, #0				@ invalid processor?

include/asm-arm/bitops.h

@@ -326,6 +326,23 @@ static inline unsigned long __ffs(unsigned long word)
 
 #define ffs(x) generic_ffs(x)
 
+/*
+ * Find first bit set in a 168-bit bitmap, where the first
+ * 128 bits are unlikely to be set.
+ */
+static inline int sched_find_first_bit(unsigned long *b)
+{
+	if (unlikely(b[0]))
+		return __ffs(b[0]);
+	if (unlikely(b[1]))
+		return __ffs(b[1]) + 32;
+	if (unlikely(b[2]))
+		return __ffs(b[2]) + 64;
+	if (b[3])
+		return __ffs(b[3]) + 96;
+	return __ffs(b[4]) + 128;
+}
+
 /*
  * hweightN: returns the hamming weight (i.e. the number
  * of bits set) of a N-bit word

include/asm-arm/mmu_context.h

@@ -49,27 +49,4 @@ switch_mm(struct mm_struct *prev, struct mm_struct *next,
 #define activate_mm(prev, next) \
 	switch_mm((prev),(next),NULL,smp_processor_id())
 
-/*
- * Find first bit set in a 168-bit bitmap, where the first
- * 128 bits are unlikely to be set.
- */
-static inline int sched_find_first_bit(unsigned long *b)
-{
-#if MAX_RT_PRIO != 128 || MAX_PRIO != 168
-#error update this function
-#endif
-
-	if (unlikely(b[0]))
-		return __ffs(b[0]);
-	if (unlikely(b[1]))
-		return __ffs(b[1]) + 32;
-	if (unlikely(b[2]))
-		return __ffs(b[2]) + 64;
-	if (unlikely(b[3]))
-		return __ffs(b[3]) + 96;
-	if (b[4])
-		return __ffs(b[4]) + MAX_RT_PRIO;
-	return __ffs(b[5]) + 32 + MAX_RT_PRIO;
-}
-
 #endif

include/asm-arm/page.h

@@ -14,8 +14,19 @@
 #define clear_page(page)	memzero((void *)(page), PAGE_SIZE)
 extern void copy_page(void *to, void *from);
 
-#define clear_user_page(page, vaddr)	cpu_clear_user_page(page,vaddr)
-#define copy_user_page(to, from, vaddr)	cpu_copy_user_page(to,from,vaddr)
+#define clear_user_page(addr,vaddr)			\
+	do {						\
+		preempt_disable();			\
+		cpu_clear_user_page(addr, vaddr);	\
+		preempt_enable();			\
+	} while (0)
+
+#define copy_user_page(to,from,vaddr)			\
+	do {						\
+		preempt_disable();			\
+		cpu_copy_user_page(to, from, vaddr);	\
+		preempt_enable();			\
+	} while (0)
 
 #ifdef STRICT_MM_TYPECHECKS
 /*

include/asm-arm/system.h

@@ -53,9 +53,9 @@ extern asmlinkage void __backtrace(void);
 struct thread_info;
 extern struct task_struct *__switch_to(struct thread_info *, struct thread_info *);
 
-#define switch_to(prev,next,last)					\
+#define switch_to(prev,next)						\
 	do {			 					\
-		last = __switch_to(prev->thread_info,next->thread_info); \
+		__switch_to(prev->thread_info,next->thread_info);	\
 		mb();							\
 	} while (0)