Merge branch 'parisc-for-3.10' of git://git.kernel.org/pub/scm/linux/kernel/git/deller/parisc-linux

Pull parisc updates from Helge Deller:
 "Main fixes and updates in this patch series are:
   - we faced kernel stack corruptions because of multiple delivery of
     interrupts
   - added kernel stack overflow checks
   - added possibility to use dedicated stacks for irq processing
   - initial support for page sizes > 4k
   - more information in /proc/interrupts (e.g.  TLB flushes and number
     of IPI calls)
   - documented how the parisc gateway page works
   - and of course quite some other smaller cleanups and fixes."

* 'parisc-for-3.10' of git://git.kernel.org/pub/scm/linux/kernel/git/deller/parisc-linux:
  parisc: tlb flush counting fix for SMP and UP
  parisc: more irq statistics in /proc/interrupts
  parisc: implement irq stacks
  parisc: add kernel stack overflow check
  parisc: only re-enable interrupts if we need to schedule or deliver signals when returning to userspace
  parisc: implement atomic64_dec_if_positive()
  parisc: use long branch in fork_like macro
  parisc: fix NATIVE set up in build
  parisc: document the parisc gateway page
  parisc: fix partly 16/64k PAGE_SIZE boot
  parisc: Provide default implementation for dma_{alloc, free}_attrs
  parisc: fix whitespace errors in arch/parisc/kernel/traps.c
  parisc: remove the second argument of kmap_atomic

20 files changed, 333 insertions, 66 deletions

diff --git a/arch/parisc/Kconfig b/arch/parisc/Kconfig
index 433e75a2ee9a..cad060f288cf 100644
--- a/arch/parisc/Kconfig
+++ b/arch/parisc/Kconfig
@@ -13,6 +13,7 @@ config PARISC
 	select BUG
 	select HAVE_PERF_EVENTS
 	select GENERIC_ATOMIC64 if !64BIT
+	select ARCH_HAS_ATOMIC64_DEC_IF_POSITIVE
 	select HAVE_GENERIC_HARDIRQS
 	select BROKEN_RODATA
 	select GENERIC_IRQ_PROBE
@@ -242,6 +243,14 @@ config SMP
 
 	  If you don't know what to do here, say N.
 
+config IRQSTACKS
+	bool "Use separate kernel stacks when processing interrupts"
+	default n
+	help
+	  If you say Y here the kernel will use separate kernel stacks
+	  for handling hard and soft interrupts.  This can help avoid
+	  overflowing the process kernel stacks.
+
 config HOTPLUG_CPU
 	bool
 	default y if SMP
diff --git a/arch/parisc/Kconfig.debug b/arch/parisc/Kconfig.debug
index bc989e522a04..08a332f6ee87 100644
--- a/arch/parisc/Kconfig.debug
+++ b/arch/parisc/Kconfig.debug
@@ -13,3 +13,14 @@ config DEBUG_RODATA
          If in doubt, say "N".
 
 endmenu
+
+config DEBUG_STACKOVERFLOW
+	bool "Check for stack overflows"
+	default y
+	depends on DEBUG_KERNEL
+	---help---
+	  Say Y here if you want to check the overflows of kernel, IRQ
+	  and exception stacks. This option will cause messages of the
+	  stacks in detail when free stack space drops below a certain
+	  limit.
+	  If in doubt, say "N".
diff --git a/arch/parisc/Makefile b/arch/parisc/Makefile
index 113e28206503..2f967cc6649e 100644
--- a/arch/parisc/Makefile
+++ b/arch/parisc/Makefile
@@ -24,9 +24,7 @@ CHECKFLAGS	+= -D__hppa__=1
 LIBGCC		= $(shell $(CC) $(KBUILD_CFLAGS) -print-libgcc-file-name)
 
 MACHINE		:= $(shell uname -m)
-ifeq ($(MACHINE),parisc*)
-NATIVE		:= 1
-endif
+NATIVE		:= $(if $(filter parisc%,$(MACHINE)),1,0)
 
 ifdef CONFIG_64BIT
 UTS_MACHINE	:= parisc64
diff --git a/arch/parisc/include/asm/atomic.h b/arch/parisc/include/asm/atomic.h
index f38e1984b242..472886ceab1d 100644
--- a/arch/parisc/include/asm/atomic.h
+++ b/arch/parisc/include/asm/atomic.h
@@ -229,6 +229,29 @@ static __inline__ int atomic64_add_unless(atomic64_t *v, long a, long u)
 
 #define atomic64_inc_not_zero(v) atomic64_add_unless((v), 1, 0)
 
+/*
+ * atomic64_dec_if_positive - decrement by 1 if old value positive
+ * @v: pointer of type atomic_t
+ *
+ * The function returns the old value of *v minus 1, even if
+ * the atomic variable, v, was not decremented.
+ */
+static inline long atomic64_dec_if_positive(atomic64_t *v)
+{
+	long c, old, dec;
+	c = atomic64_read(v);
+	for (;;) {
+		dec = c - 1;
+		if (unlikely(dec < 0))
+			break;
+		old = atomic64_cmpxchg((v), c, dec);
+		if (likely(old == c))
+			break;
+		c = old;
+	}
+	return dec;
+}
+
 #endif /* !CONFIG_64BIT */
 
 
diff --git a/arch/parisc/include/asm/dma-mapping.h b/arch/parisc/include/asm/dma-mapping.h
index 106b395688e1..d0eae5f2bd87 100644
--- a/arch/parisc/include/asm/dma-mapping.h
+++ b/arch/parisc/include/asm/dma-mapping.h
@@ -46,6 +46,9 @@ extern struct hppa_dma_ops pcx_dma_ops;
 
 extern struct hppa_dma_ops *hppa_dma_ops;
 
+#define dma_alloc_attrs(d, s, h, f, a) dma_alloc_coherent(d, s, h, f)
+#define dma_free_attrs(d, s, h, f, a) dma_free_coherent(d, s, h, f)
+
 static inline void *
 dma_alloc_coherent(struct device *dev, size_t size, dma_addr_t *dma_handle,
 		   gfp_t flag)
diff --git a/arch/parisc/include/asm/hardirq.h b/arch/parisc/include/asm/hardirq.h
index 0d68184a76cb..12373c4dabab 100644
--- a/arch/parisc/include/asm/hardirq.h
+++ b/arch/parisc/include/asm/hardirq.h
@@ -1,11 +1,41 @@
 /* hardirq.h: PA-RISC hard IRQ support.
  *
  * Copyright (C) 2001 Matthew Wilcox <matthew@wil.cx>
+ * Copyright (C) 2013 Helge Deller <deller@gmx.de>
  */
 
 #ifndef _PARISC_HARDIRQ_H
 #define _PARISC_HARDIRQ_H
 
-#include <asm-generic/hardirq.h>
+#include <linux/cache.h>
+#include <linux/threads.h>
+#include <linux/irq.h>
+
+typedef struct {
+	unsigned int __softirq_pending;
+#ifdef CONFIG_DEBUG_STACKOVERFLOW
+	unsigned int kernel_stack_usage;
+#endif
+#ifdef CONFIG_SMP
+	unsigned int irq_resched_count;
+	unsigned int irq_call_count;
+#endif
+	unsigned int irq_tlb_count;
+} ____cacheline_aligned irq_cpustat_t;
+
+DECLARE_PER_CPU_SHARED_ALIGNED(irq_cpustat_t, irq_stat);
+
+#define __ARCH_IRQ_STAT
+#define __IRQ_STAT(cpu, member) (irq_stat[cpu].member)
+#define inc_irq_stat(member)	this_cpu_inc(irq_stat.member)
+#define local_softirq_pending()	this_cpu_read(irq_stat.__softirq_pending)
+
+#define __ARCH_SET_SOFTIRQ_PENDING
+
+#define set_softirq_pending(x)	\
+		this_cpu_write(irq_stat.__softirq_pending, (x))
+#define or_softirq_pending(x)	this_cpu_or(irq_stat.__softirq_pending, (x))
+
+#define ack_bad_irq(irq) WARN(1, "unexpected IRQ trap at vector %02x\n", irq)
 
 #endif /* _PARISC_HARDIRQ_H */
diff --git a/arch/parisc/include/asm/processor.h b/arch/parisc/include/asm/processor.h
index 09b54a57a48d..064015547d1e 100644
--- a/arch/parisc/include/asm/processor.h
+++ b/arch/parisc/include/asm/processor.h
@@ -20,8 +20,6 @@
 
 #endif /* __ASSEMBLY__ */
 
-#define KERNEL_STACK_SIZE 	(4*PAGE_SIZE)
-
 /*
  * Default implementation of macro that returns current
  * instruction pointer ("program counter").
@@ -61,6 +59,23 @@
 #ifndef __ASSEMBLY__
 
 /*
+ * IRQ STACK - used for irq handler
+ */
+#ifdef __KERNEL__
+
+#define IRQ_STACK_SIZE      (4096 << 2) /* 16k irq stack size */
+
+union irq_stack_union {
+	unsigned long stack[IRQ_STACK_SIZE/sizeof(unsigned long)];
+};
+
+DECLARE_PER_CPU(union irq_stack_union, irq_stack_union);
+
+void call_on_stack(unsigned long p1, void *func, unsigned long new_stack);
+
+#endif /* __KERNEL__ */
+
+/*
  * Data detected about CPUs at boot time which is the same for all CPU's.
  * HP boxes are SMP - ie identical processors.
  *
@@ -97,7 +112,6 @@ struct cpuinfo_parisc {
 	unsigned long txn_addr;     /* MMIO addr of EIR or id_eid */
 #ifdef CONFIG_SMP
 	unsigned long pending_ipi;  /* bitmap of type ipi_message_type */
-	unsigned long ipi_count;    /* number ipi Interrupts */
 #endif
 	unsigned long bh_count;     /* number of times bh was invoked */
 	unsigned long prof_counter; /* per CPU profiling support */
diff --git a/arch/parisc/include/asm/thread_info.h b/arch/parisc/include/asm/thread_info.h
index 6182832e5b6c..540c88fa8f86 100644
--- a/arch/parisc/include/asm/thread_info.h
+++ b/arch/parisc/include/asm/thread_info.h
@@ -40,7 +40,7 @@ struct thread_info {
 
 /* thread information allocation */
 
-#define THREAD_SIZE_ORDER            2
+#define THREAD_SIZE_ORDER	2 /* PA-RISC requires at least 16k stack */
 /* Be sure to hunt all references to this down when you change the size of
  * the kernel stack */
 #define THREAD_SIZE             (PAGE_SIZE << THREAD_SIZE_ORDER)
diff --git a/arch/parisc/include/asm/tlbflush.h b/arch/parisc/include/asm/tlbflush.h
index 8f1a8100bf2d..5273da991e06 100644
--- a/arch/parisc/include/asm/tlbflush.h
+++ b/arch/parisc/include/asm/tlbflush.h
@@ -22,6 +22,8 @@ extern spinlock_t pa_tlb_lock;
 extern void flush_tlb_all(void);
 extern void flush_tlb_all_local(void *);
 
+#define smp_flush_tlb_all()	flush_tlb_all()
+
 /*
  * flush_tlb_mm()
  *
diff --git a/arch/parisc/kernel/cache.c b/arch/parisc/kernel/cache.c
index 83ded26cad06..65fb4cbc3a0f 100644
--- a/arch/parisc/kernel/cache.c
+++ b/arch/parisc/kernel/cache.c
@@ -606,7 +606,7 @@ void clear_user_highpage(struct page *page, unsigned long vaddr)
 	/* Clear using TMPALIAS region.  The page doesn't need to
 	   be flushed but the kernel mapping needs to be purged.  */
 
-	vto = kmap_atomic(page, KM_USER0);
+	vto = kmap_atomic(page);
 
 	/* The PA-RISC 2.0 Architecture book states on page F-6:
 	   "Before a write-capable translation is enabled, *all*
@@ -641,8 +641,8 @@ void copy_user_highpage(struct page *to, struct page *from,
 	   the `to' page must be flushed in copy_user_page_asm since
 	   it can be used to bring in executable code.  */
 
-	vfrom = kmap_atomic(from, KM_USER0);
-	vto = kmap_atomic(to, KM_USER1);
+	vfrom = kmap_atomic(from);
+	vto = kmap_atomic(to);
 
 	purge_kernel_dcache_page_asm((unsigned long)vto);
 	purge_tlb_start(flags);
diff --git a/arch/parisc/kernel/entry.S b/arch/parisc/kernel/entry.S
index f33201bf8977..4bb96ad9b0b1 100644
--- a/arch/parisc/kernel/entry.S
+++ b/arch/parisc/kernel/entry.S
@@ -400,7 +400,15 @@
 #if PT_NLEVELS == 3
 	extru		\va,31-ASM_PMD_SHIFT,ASM_BITS_PER_PMD,\index
 #else
+# if defined(CONFIG_64BIT)
+	extrd,u		\va,63-ASM_PGDIR_SHIFT,ASM_BITS_PER_PGD,\index
+  #else
+  # if PAGE_SIZE > 4096
+	extru		\va,31-ASM_PGDIR_SHIFT,32-ASM_PGDIR_SHIFT,\index
+  # else
 	extru		\va,31-ASM_PGDIR_SHIFT,ASM_BITS_PER_PGD,\index
+  # endif
+# endif
 #endif
 	dep             %r0,31,PAGE_SHIFT,\pmd  /* clear offset */
 	copy		%r0,\pte
@@ -615,7 +623,7 @@
 
 	.text
 
-	.align	PAGE_SIZE
+	.align 4096
 
 ENTRY(fault_vector_20)
 	/* First vector is invalid (0) */
@@ -825,11 +833,6 @@ ENTRY(syscall_exit_rfi)
 	STREG   %r19,PT_SR7(%r16)
 
 intr_return:
-	/* NOTE: Need to enable interrupts incase we schedule. */
-	ssm     PSW_SM_I, %r0
-
-intr_check_resched:
-
 	/* check for reschedule */
 	mfctl   %cr30,%r1
 	LDREG   TI_FLAGS(%r1),%r19	/* sched.h: TIF_NEED_RESCHED */
@@ -856,6 +859,11 @@ intr_check_sig:
 	LDREG	PT_IASQ1(%r16), %r20
 	cmpib,COND(=),n 0,%r20,intr_restore /* backward */
 
+	/* NOTE: We need to enable interrupts if we have to deliver
+	 * signals. We used to do this earlier but it caused kernel
+	 * stack overflows. */
+	ssm     PSW_SM_I, %r0
+
 	copy	%r0, %r25			/* long in_syscall = 0 */
 #ifdef CONFIG_64BIT
 	ldo	-16(%r30),%r29			/* Reference param save area */
@@ -907,6 +915,10 @@ intr_do_resched:
 	cmpib,COND(=)	0, %r20, intr_do_preempt
 	nop
 
+	/* NOTE: We need to enable interrupts if we schedule.  We used
+	 * to do this earlier but it caused kernel stack overflows. */
+	ssm     PSW_SM_I, %r0
+
 #ifdef CONFIG_64BIT
 	ldo	-16(%r30),%r29		/* Reference param save area */
 #endif
@@ -1694,7 +1706,8 @@ ENTRY(sys_\name\()_wrapper)
 	ldo	TASK_REGS(%r1),%r1
 	reg_save %r1
 	mfctl	%cr27, %r28
-	b	sys_\name
+	ldil	L%sys_\name, %r31
+	be	R%sys_\name(%sr4,%r31)
 	STREG	%r28, PT_CR27(%r1)
 ENDPROC(sys_\name\()_wrapper)
 	.endm
@@ -1997,6 +2010,47 @@ ftrace_stub:
 ENDPROC(return_to_handler)
 #endif	/* CONFIG_FUNCTION_TRACER */
 
+#ifdef CONFIG_IRQSTACKS
+/* void call_on_stack(unsigned long param1, void *func,
+		      unsigned long new_stack) */
+ENTRY(call_on_stack)
+	copy	%sp, %r1
+
+	/* Regarding the HPPA calling conventions for function pointers,
+	   we assume the PIC register is not changed across call.  For
+	   CONFIG_64BIT, the argument pointer is left to point at the
+	   argument region allocated for the call to call_on_stack. */
+# ifdef CONFIG_64BIT
+	/* Switch to new stack.  We allocate two 128 byte frames.  */
+	ldo	256(%arg2), %sp
+	/* Save previous stack pointer and return pointer in frame marker */
+	STREG	%rp, -144(%sp)
+	/* Calls always use function descriptor */
+	LDREG	16(%arg1), %arg1
+	bve,l	(%arg1), %rp
+	STREG	%r1, -136(%sp)
+	LDREG	-144(%sp), %rp
+	bve	(%rp)
+	LDREG	-136(%sp), %sp
+# else
+	/* Switch to new stack.  We allocate two 64 byte frames.  */
+	ldo	128(%arg2), %sp
+	/* Save previous stack pointer and return pointer in frame marker */
+	STREG	%r1, -68(%sp)
+	STREG	%rp, -84(%sp)
+	/* Calls use function descriptor if PLABEL bit is set */
+	bb,>=,n	%arg1, 30, 1f
+	depwi	0,31,2, %arg1
+	LDREG	0(%arg1), %arg1
+1:
+	be,l	0(%sr4,%arg1), %sr0, %r31
+	copy	%r31, %rp
+	LDREG	-84(%sp), %rp
+	bv	(%rp)
+	LDREG	-68(%sp), %sp
+# endif /* CONFIG_64BIT */
+ENDPROC(call_on_stack)
+#endif /* CONFIG_IRQSTACKS */
 
 get_register:
 	/*
diff --git a/arch/parisc/kernel/hpmc.S b/arch/parisc/kernel/hpmc.S
index 5595a2f31181..e158b6fbf1b4 100644
--- a/arch/parisc/kernel/hpmc.S
+++ b/arch/parisc/kernel/hpmc.S
@@ -55,13 +55,13 @@
 	 * IODC requires 7K byte stack.  That leaves 1K byte for os_hpmc.
 	 */
 
-	.align	PAGE_SIZE
+	.align 4096
 hpmc_stack:
 	.block 16384
 
 #define HPMC_IODC_BUF_SIZE 0x8000
 
-	.align	PAGE_SIZE
+	.align 4096
 hpmc_iodc_buf:
 	.block HPMC_IODC_BUF_SIZE
 
diff --git a/arch/parisc/kernel/irq.c b/arch/parisc/kernel/irq.c
index 8094d3ed3b64..e255db0bb761 100644
--- a/arch/parisc/kernel/irq.c
+++ b/arch/parisc/kernel/irq.c
@@ -152,6 +152,39 @@ static struct irq_chip cpu_interrupt_type = {
 	.irq_retrigger	= NULL,
 };
 
+DEFINE_PER_CPU_SHARED_ALIGNED(irq_cpustat_t, irq_stat);
+#define irq_stats(x)		(&per_cpu(irq_stat, x))
+
+/*
+ * /proc/interrupts printing for arch specific interrupts
+ */
+int arch_show_interrupts(struct seq_file *p, int prec)
+{
+	int j;
+
+#ifdef CONFIG_DEBUG_STACKOVERFLOW
+	seq_printf(p, "%*s: ", prec, "STK");
+	for_each_online_cpu(j)
+		seq_printf(p, "%10u ", irq_stats(j)->kernel_stack_usage);
+	seq_printf(p, "  Kernel stack usage\n");
+#endif
+#ifdef CONFIG_SMP
+	seq_printf(p, "%*s: ", prec, "RES");
+	for_each_online_cpu(j)
+		seq_printf(p, "%10u ", irq_stats(j)->irq_resched_count);
+	seq_printf(p, "  Rescheduling interrupts\n");
+	seq_printf(p, "%*s: ", prec, "CAL");
+	for_each_online_cpu(j)
+		seq_printf(p, "%10u ", irq_stats(j)->irq_call_count);
+	seq_printf(p, "  Function call interrupts\n");
+#endif
+	seq_printf(p, "%*s: ", prec, "TLB");
+	for_each_online_cpu(j)
+		seq_printf(p, "%10u ", irq_stats(j)->irq_tlb_count);
+	seq_printf(p, "  TLB shootdowns\n");
+	return 0;
+}
+
 int show_interrupts(struct seq_file *p, void *v)
 {
 	int i = *(loff_t *) v, j;
@@ -219,6 +252,9 @@ int show_interrupts(struct seq_file *p, void *v)
 		raw_spin_unlock_irqrestore(&desc->lock, flags);
 	}
 
+	if (i == NR_IRQS)
+		arch_show_interrupts(p, 3);
+
 	return 0;
 }
 
@@ -330,6 +366,66 @@ static inline int eirr_to_irq(unsigned long eirr)
 	return (BITS_PER_LONG - bit) + TIMER_IRQ;
 }
 
+int sysctl_panic_on_stackoverflow = 1;
+
+static inline void stack_overflow_check(struct pt_regs *regs)
+{
+#ifdef CONFIG_DEBUG_STACKOVERFLOW
+	#define STACK_MARGIN	(256*6)
+
+	/* Our stack starts directly behind the thread_info struct. */
+	unsigned long stack_start = (unsigned long) current_thread_info();
+	unsigned long sp = regs->gr[30];
+	unsigned long stack_usage;
+	unsigned int *last_usage;
+
+	/* if sr7 != 0, we interrupted a userspace process which we do not want
+	 * to check for stack overflow. We will only check the kernel stack. */
+	if (regs->sr[7])
+		return;
+
+	/* calculate kernel stack usage */
+	stack_usage = sp - stack_start;
+	last_usage = &per_cpu(irq_stat.kernel_stack_usage, smp_processor_id());
+
+	if (unlikely(stack_usage > *last_usage))
+		*last_usage = stack_usage;
+
+	if (likely(stack_usage < (THREAD_SIZE - STACK_MARGIN)))
+		return;
+
+	pr_emerg("stackcheck: %s will most likely overflow kernel stack "
+		 "(sp:%lx, stk bottom-top:%lx-%lx)\n",
+		current->comm, sp, stack_start, stack_start + THREAD_SIZE);
+
+	if (sysctl_panic_on_stackoverflow)
+		panic("low stack detected by irq handler - check messages\n");
+#endif
+}
+
+#ifdef CONFIG_IRQSTACKS
+DEFINE_PER_CPU(union irq_stack_union, irq_stack_union);
+
+static void execute_on_irq_stack(void *func, unsigned long param1)
+{
+	unsigned long *irq_stack_start;
+	unsigned long irq_stack;
+	int cpu = smp_processor_id();
+
+	irq_stack_start = &per_cpu(irq_stack_union, cpu).stack[0];
+	irq_stack = (unsigned long) irq_stack_start;
+	irq_stack = ALIGN(irq_stack, 16); /* align for stack frame usage */
+
+	BUG_ON(*irq_stack_start); /* report bug if we were called recursive. */
+	*irq_stack_start = 1;
+
+	/* This is where we switch to the IRQ stack. */
+	call_on_stack(param1, func, irq_stack);
+
+	*irq_stack_start = 0;
+}
+#endif /* CONFIG_IRQSTACKS */
+
 /* ONLY called from entry.S:intr_extint() */
 void do_cpu_irq_mask(struct pt_regs *regs)
 {
@@ -364,7 +460,13 @@ void do_cpu_irq_mask(struct pt_regs *regs)
 		goto set_out;
 	}
 #endif
+	stack_overflow_check(regs);
+
+#ifdef CONFIG_IRQSTACKS
+	execute_on_irq_stack(&generic_handle_irq, irq);
+#else
 	generic_handle_irq(irq);
+#endif /* CONFIG_IRQSTACKS */
 
  out:
 	irq_exit();
@@ -420,6 +522,4 @@ void __init init_IRQ(void)
 	cpu_eiem = EIEM_MASK(TIMER_IRQ);
 #endif
         set_eiem(cpu_eiem);	/* EIEM : enable all external intr */
-
 }
-
diff --git a/arch/parisc/kernel/pacache.S b/arch/parisc/kernel/pacache.S
index 312b48422a56..5e1de6072be5 100644
--- a/arch/parisc/kernel/pacache.S
+++ b/arch/parisc/kernel/pacache.S
@@ -563,6 +563,15 @@ ENDPROC(copy_page_asm)
  *          %r23 physical page (shifted for tlb insert) of "from" translation
  */
 
+        /* Drop prot bits and convert to page addr for iitlbt and idtlbt */
+        #define PAGE_ADD_SHIFT  (PAGE_SHIFT-12)
+        .macro          convert_phys_for_tlb_insert20  phys
+        extrd,u         \phys, 56-PAGE_ADD_SHIFT, 32-PAGE_ADD_SHIFT, \phys
+#if _PAGE_SIZE_ENCODING_DEFAULT
+        depdi           _PAGE_SIZE_ENCODING_DEFAULT, 63, (63-58), \phys
+#endif
+	.endm
+
 	/*
 	 * We can't do this since copy_user_page is used to bring in
 	 * file data that might have instructions. Since the data would
@@ -589,15 +598,14 @@ ENTRY(copy_user_page_asm)
 	sub		%r25, %r1, %r23
 
 	ldil		L%(TMPALIAS_MAP_START), %r28
-	/* FIXME for different page sizes != 4k */
 #ifdef CONFIG_64BIT
 #if (TMPALIAS_MAP_START >= 0x80000000)
 	depdi		0, 31,32, %r28		/* clear any sign extension */
 #endif
-	extrd,u		%r26,56,32, %r26	/* convert phys addr to tlb insert format */
-	extrd,u		%r23,56,32, %r23	/* convert phys addr to tlb insert format */
+	convert_phys_for_tlb_insert20 %r26	/* convert phys addr to tlb insert format */
+	convert_phys_for_tlb_insert20 %r23	/* convert phys addr to tlb insert format */
 	depd		%r24,63,22, %r28	/* Form aliased virtual address 'to' */
-	depdi		0, 63,12, %r28		/* Clear any offset bits */
+	depdi		0, 63,PAGE_SHIFT, %r28  /* Clear any offset bits */
 	copy		%r28, %r29
 	depdi		1, 41,1, %r29		/* Form aliased virtual address 'from' */
 #else
@@ -747,11 +755,10 @@ ENTRY(clear_user_page_asm)
 #ifdef CONFIG_64BIT
 #if (TMPALIAS_MAP_START >= 0x80000000)
 	depdi		0, 31,32, %r28		/* clear any sign extension */
-	/* FIXME: page size dependend */
 #endif
-	extrd,u		%r26, 56,32, %r26	/* convert phys addr to tlb insert format */
+	convert_phys_for_tlb_insert20 %r26	/* convert phys addr to tlb insert format */
 	depd		%r25, 63,22, %r28	/* Form aliased virtual address 'to' */
-	depdi		0, 63,12, %r28		/* Clear any offset bits */
+	depdi		0, 63,PAGE_SHIFT, %r28	/* Clear any offset bits */
 #else
 	extrw,u		%r26, 24,25, %r26	/* convert phys addr to tlb insert format */
 	depw		%r25, 31,22, %r28	/* Form aliased virtual address 'to' */
@@ -832,11 +839,10 @@ ENTRY(flush_dcache_page_asm)
 #ifdef CONFIG_64BIT
 #if (TMPALIAS_MAP_START >= 0x80000000)
 	depdi		0, 31,32, %r28		/* clear any sign extension */
-	/* FIXME: page size dependend */
 #endif
-	extrd,u		%r26, 56,32, %r26	/* convert phys addr to tlb insert format */
+	convert_phys_for_tlb_insert20 %r26	/* convert phys addr to tlb insert format */
 	depd		%r25, 63,22, %r28	/* Form aliased virtual address 'to' */
-	depdi		0, 63,12, %r28		/* Clear any offset bits */
+	depdi		0, 63,PAGE_SHIFT, %r28	/* Clear any offset bits */
 #else
 	extrw,u		%r26, 24,25, %r26	/* convert phys addr to tlb insert format */
 	depw		%r25, 31,22, %r28	/* Form aliased virtual address 'to' */
@@ -909,11 +915,10 @@ ENTRY(flush_icache_page_asm)
 #ifdef CONFIG_64BIT
 #if (TMPALIAS_MAP_START >= 0x80000000)
 	depdi		0, 31,32, %r28		/* clear any sign extension */
-	/* FIXME: page size dependend */
 #endif
-	extrd,u		%r26, 56,32, %r26	/* convert phys addr to tlb insert format */
+	convert_phys_for_tlb_insert20 %r26	/* convert phys addr to tlb insert format */
 	depd		%r25, 63,22, %r28	/* Form aliased virtual address 'to' */
-	depdi		0, 63,12, %r28		/* Clear any offset bits */
+	depdi		0, 63,PAGE_SHIFT, %r28  /* Clear any offset bits */
 #else
 	extrw,u		%r26, 24,25, %r26	/* convert phys addr to tlb insert format */
 	depw		%r25, 31,22, %r28	/* Form aliased virtual address 'to' */
@@ -959,7 +964,7 @@ ENTRY(flush_icache_page_asm)
 	fic,m		%r1(%sr4,%r28)
 	fic,m		%r1(%sr4,%r28)
 	fic,m		%r1(%sr4,%r28)
-	cmpb,COND(<<)		%r28, %r25,1b
+	cmpb,COND(<<)	%r28, %r25,1b
 	fic,m		%r1(%sr4,%r28)
 
 	sync
diff --git a/arch/parisc/kernel/setup.c b/arch/parisc/kernel/setup.c
index a3328c2616b0..76b63e726a53 100644
--- a/arch/parisc/kernel/setup.c
+++ b/arch/parisc/kernel/setup.c
@@ -129,6 +129,8 @@ void __init setup_arch(char **cmdline_p)
 	printk(KERN_INFO "The 32-bit Kernel has started...\n");
 #endif
 
+	printk(KERN_INFO "Default page size is %dKB.\n", (int)(PAGE_SIZE / 1024));
+
 	pdc_console_init();
 
 #ifdef CONFIG_64BIT
diff --git a/arch/parisc/kernel/smp.c b/arch/parisc/kernel/smp.c
index fd1bb1519c2b..e3614fb343e5 100644
--- a/arch/parisc/kernel/smp.c
+++ b/arch/parisc/kernel/smp.c
@@ -127,7 +127,7 @@ ipi_interrupt(int irq, void *dev_id)
 	unsigned long flags;
 
 	/* Count this now; we may make a call that never returns. */
-	p->ipi_count++;
+	inc_irq_stat(irq_call_count);
 
 	mb();	/* Order interrupt and bit testing. */
 
@@ -155,6 +155,7 @@ ipi_interrupt(int irq, void *dev_id)
 				
 			case IPI_RESCHEDULE:
 				smp_debug(100, KERN_DEBUG "CPU%d IPI_RESCHEDULE\n", this_cpu);
+				inc_irq_stat(irq_resched_count);
 				scheduler_ipi();
 				break;
 
@@ -263,17 +264,6 @@ void arch_send_call_function_single_ipi(int cpu)
 }
 
 /*
- * Flush all other CPU's tlb and then mine.  Do this with on_each_cpu()
- * as we want to ensure all TLB's flushed before proceeding.
- */
-
-void
-smp_flush_tlb_all(void)
-{
-	on_each_cpu(flush_tlb_all_local, NULL, 1);
-}
-
-/*
  * Called by secondaries to update state and initialize CPU registers.
  */
 static void __init
diff --git a/arch/parisc/kernel/syscall.S b/arch/parisc/kernel/syscall.S
index 5e055240f00b..e767ab733e32 100644
--- a/arch/parisc/kernel/syscall.S
+++ b/arch/parisc/kernel/syscall.S
@@ -1,12 +1,35 @@
 /* 
  * Linux/PA-RISC Project (http://www.parisc-linux.org/)
  * 
- * System call entry code Copyright (c) Matthew Wilcox 1999 <willy@bofh.ai>
+ * System call entry code / Linux gateway page
+ * Copyright (c) Matthew Wilcox 1999 <willy@bofh.ai>
  * Licensed under the GNU GPL.
  * thanks to Philipp Rumpf, Mike Shaver and various others
  * sorry about the wall, puffin..
  */
 
+/*
+How does the Linux gateway page on PA-RISC work?
+------------------------------------------------
+The Linux gateway page on PA-RISC is "special".
+It actually has PAGE_GATEWAY bits set (this is linux terminology; in parisc
+terminology it's Execute, promote to PL0) in the page map.  So anything
+executing on this page executes with kernel level privilege (there's more to it
+than that: to have this happen, you also have to use a branch with a ,gate
+completer to activate the privilege promotion).  The upshot is that everything
+that runs on the gateway page runs at kernel privilege but with the current
+user process address space (although you have access to kernel space via %sr2).
+For the 0x100 syscall entry, we redo the space registers to point to the kernel
+address space (preserving the user address space in %sr3), move to wide mode if
+required, save the user registers and branch into the kernel syscall entry
+point.  For all the other functions, we execute at kernel privilege but don't
+flip address spaces. The basic upshot of this is that these code snippets are
+executed atomically (because the kernel can't be pre-empted) and they may
+perform architecturally forbidden (to PL3) operations (like setting control
+registers).
+*/
+
+
 #include <asm/asm-offsets.h>
 #include <asm/unistd.h>
 #include <asm/errno.h>
@@ -15,6 +38,7 @@
 #include <asm/thread_info.h>
 #include <asm/assembly.h>
 #include <asm/processor.h>
+#include <asm/cache.h>
 
 #include <linux/linkage.h>
 
@@ -643,7 +667,7 @@ ENTRY(end_linux_gateway_page)
 
 	.section .rodata,"a"
 
-	.align PAGE_SIZE
+	.align 8
 	/* Light-weight-syscall table */
 	/* Start of lws table. */
 ENTRY(lws_table)
@@ -652,13 +676,13 @@ ENTRY(lws_table)
 END(lws_table)
 	/* End of lws table */
 
-	.align PAGE_SIZE
+	.align 8
 ENTRY(sys_call_table)
 #include "syscall_table.S"
 END(sys_call_table)
 
 #ifdef CONFIG_64BIT
-	.align PAGE_SIZE
+	.align 8
 ENTRY(sys_call_table64)
 #define SYSCALL_TABLE_64BIT
 #include "syscall_table.S"
@@ -674,7 +698,7 @@ END(sys_call_table64)
 		with ldcw.
 	*/
 	.section .data
-	.align	PAGE_SIZE
+	.align	L1_CACHE_BYTES
 ENTRY(lws_lock_start)
 	/* lws locks */
 	.rept 16
diff --git a/arch/parisc/kernel/traps.c b/arch/parisc/kernel/traps.c
index f702bff0bed9..fe41a98043bb 100644
--- a/arch/parisc/kernel/traps.c
+++ b/arch/parisc/kernel/traps.c
@@ -522,10 +522,10 @@ void notrace handle_interruption(int code, struct pt_regs *regs)
 	 */
 	if (((unsigned long)regs->iaoq[0] & 3) &&
 	    ((unsigned long)regs->iasq[0] != (unsigned long)regs->sr[7])) { 
-	  	/* Kill the user process later */
-	  	regs->iaoq[0] = 0 | 3;
+		/* Kill the user process later */
+		regs->iaoq[0] = 0 | 3;
 		regs->iaoq[1] = regs->iaoq[0] + 4;
-	 	regs->iasq[0] = regs->iasq[1] = regs->sr[7];
+		regs->iasq[0] = regs->iasq[1] = regs->sr[7];
 		regs->gr[0] &= ~PSW_B;
 		return;
 	}
@@ -541,8 +541,8 @@ void notrace handle_interruption(int code, struct pt_regs *regs)
 		
 		/* set up a new led state on systems shipped with a LED State panel */
 		pdc_chassis_send_status(PDC_CHASSIS_DIRECT_HPMC);
-		    
-	    	parisc_terminate("High Priority Machine Check (HPMC)",
+
+		parisc_terminate("High Priority Machine Check (HPMC)",
 				regs, code, 0);
 		/* NOT REACHED */
 		
@@ -584,13 +584,13 @@ void notrace handle_interruption(int code, struct pt_regs *regs)
 		/* Break instruction trap */
 		handle_break(regs);
 		return;
-	
+
 	case 10:
 		/* Privileged operation trap */
 		die_if_kernel("Privileged operation", regs, code);
 		si.si_code = ILL_PRVOPC;
 		goto give_sigill;
-	
+
 	case 11:
 		/* Privileged register trap */
 		if ((regs->iir & 0xffdfffe0) == 0x034008a0) {
@@ -634,7 +634,7 @@ void notrace handle_interruption(int code, struct pt_regs *regs)
 		if(user_mode(regs)){
 			si.si_signo = SIGFPE;
 			/* Set to zero, and let the userspace app figure it out from
-		   	   the insn pointed to by si_addr */
+			   the insn pointed to by si_addr */
 			si.si_code = 0;
 			si.si_addr = (void __user *) regs->iaoq[0];
 			force_sig_info(SIGFPE, &si, current);
@@ -648,7 +648,7 @@ void notrace handle_interruption(int code, struct pt_regs *regs)
 		die_if_kernel("Floating point exception", regs, 0); /* quiet */
 		handle_fpe(regs);
 		return;
-		
+
 	case 15:
 		/* Data TLB miss fault/Data page fault */
 		/* Fall through */
@@ -660,15 +660,15 @@ void notrace handle_interruption(int code, struct pt_regs *regs)
 	case 17:
 		/* Non-access data TLB miss fault/Non-access data page fault */
 		/* FIXME: 
-		 	 Still need to add slow path emulation code here!
-		         If the insn used a non-shadow register, then the tlb
+			 Still need to add slow path emulation code here!
+			 If the insn used a non-shadow register, then the tlb
 			 handlers could not have their side-effect (e.g. probe
 			 writing to a target register) emulated since rfir would
 			 erase the changes to said register. Instead we have to
 			 setup everything, call this function we are in, and emulate
 			 by hand. Technically we need to emulate:
 			 fdc,fdce,pdc,"fic,4f",prober,probeir,probew, probeiw
-		*/			  
+		*/
 		fault_address = regs->ior;
 		fault_space = regs->isr;
 		break;
diff --git a/arch/parisc/kernel/vmlinux.lds.S b/arch/parisc/kernel/vmlinux.lds.S
index 64a999882e4f..4bb095a2f6fc 100644
--- a/arch/parisc/kernel/vmlinux.lds.S
+++ b/arch/parisc/kernel/vmlinux.lds.S
@@ -95,7 +95,7 @@ SECTIONS
 	NOTES
 
 	/* Data */
-	RW_DATA_SECTION(L1_CACHE_BYTES, PAGE_SIZE, THREAD_SIZE)
+	RW_DATA_SECTION(L1_CACHE_BYTES, PAGE_SIZE, PAGE_SIZE)
 
 	/* PA-RISC locks requires 16-byte alignment */
 	. = ALIGN(16);
diff --git a/arch/parisc/mm/init.c b/arch/parisc/mm/init.c
index 157b931e7b09..ce939ac8622b 100644
--- a/arch/parisc/mm/init.c
+++ b/arch/parisc/mm/init.c
@@ -1069,6 +1069,7 @@ void flush_tlb_all(void)
 {
 	int do_recycle;
 
+	inc_irq_stat(irq_tlb_count);
 	do_recycle = 0;
 	spin_lock(&sid_lock);
 	if (dirty_space_ids > RECYCLE_THRESHOLD) {
@@ -1089,6 +1090,7 @@ void flush_tlb_all(void)
 #else
 void flush_tlb_all(void)
 {
+	inc_irq_stat(irq_tlb_count);
 	spin_lock(&sid_lock);
 	flush_tlb_all_local(NULL);
 	recycle_sids();