Merge branch 'for-linus' of git://git390.osdl.marist.edu/pub/scm/linux-2.6

* 'for-linus' of git://git390.osdl.marist.edu/pub/scm/linux-2.6:
  [S390] cio: Call cancel_halt_clear even when actl == 0.
  [S390] cio: Use path verification to check for path state.
  [S390] cio: Fix locking when calling notify function.
  [S390] Fixed handling of access register mode faults.
  [S390] dasd: Use default recovery for SNSS requests
  [S390] check_bugs() should be inline.
  [S390] tape: Compression overwrites crypto setting
  [S390] nss: disable kexec.
  [S390] reipl: move dump_prefix_page out of text section.
  [S390] smp: disable preemption in smp_call_function/smp_call_function_on
  [S390] kprobes breaks BUG_ON

10 files changed, 103 insertions, 97 deletions

diff --git a/arch/s390/Kconfig b/arch/s390/Kconfig
index d9425f59be91..0f293aa7b0fa 100644
--- a/arch/s390/Kconfig
+++ b/arch/s390/Kconfig
@@ -376,6 +376,8 @@ config SHARED_KERNEL
 	  Select this option, if you want to share the text segment of the
 	  Linux kernel between different VM guests. This reduces memory
 	  usage with lots of guests but greatly increases kernel size.
+	  Also if a kernel was IPL'ed from a shared segment the kexec system
+	  call will not work.
 	  You should only select this option if you know what you are
 	  doing and want to exploit this feature.
 
diff --git a/arch/s390/kernel/head31.S b/arch/s390/kernel/head31.S
index da7c8bb80982..dc364c1419af 100644
--- a/arch/s390/kernel/head31.S
+++ b/arch/s390/kernel/head31.S
@@ -121,7 +121,7 @@ startup_continue:
 	.long	.Lduct			# cr2: dispatchable unit control table
 	.long	0			# cr3: instruction authorization
 	.long	0			# cr4: instruction authorization
-	.long	0xffffffff		# cr5: primary-aste origin
+	.long	.Lduct			# cr5: primary-aste origin
 	.long	0			# cr6:	I/O interrupts
 	.long	0			# cr7:	secondary space segment table
 	.long	0			# cr8:	access registers translation
@@ -132,8 +132,6 @@ startup_continue:
 	.long	0			# cr13: home space segment table
 	.long	0xc0000000		# cr14: machine check handling off
 	.long	0			# cr15: linkage stack operations
-.Lduct:	.long	0,0,0,0,0,0,0,0
-	.long	0,0,0,0,0,0,0,0
 .Lpcfpu:.long	0x00080000,0x80000000 + .Lchkfpu
 .Lpccsp:.long	0x00080000,0x80000000 + .Lchkcsp
 .Lpcmvpg:.long	0x00080000,0x80000000 + .Lchkmvpg
@@ -147,6 +145,13 @@ startup_continue:
 .Linittu:   .long init_thread_union
 .Lstartup_init:
 	    .long startup_init
+	.align	64
+.Lduct:	.long	0,0,0,0,.Lduald,0,0,0
+	.long	0,0,0,0,0,0,0,0
+	.align	128
+.Lduald:.rept	8
+	.long	0x80000000,0,0,0	# invalid access-list entries
+	.endr
 
 	.org	0x12000
 	.globl	_ehead
diff --git a/arch/s390/kernel/head64.S b/arch/s390/kernel/head64.S
index af09e18cc5d0..37010709fe68 100644
--- a/arch/s390/kernel/head64.S
+++ b/arch/s390/kernel/head64.S
@@ -134,7 +134,7 @@ startup_continue:
 	.quad	.Lduct			# cr2: dispatchable unit control table
 	.quad	0			# cr3: instruction authorization
 	.quad	0			# cr4: instruction authorization
-	.quad	0xffffffffffffffff	# cr5: primary-aste origin
+	.quad	.Lduct			# cr5: primary-aste origin
 	.quad	0			# cr6:	I/O interrupts
 	.quad	0			# cr7:	secondary space segment table
 	.quad	0			# cr8:	access registers translation
@@ -145,14 +145,19 @@ startup_continue:
 	.quad	0			# cr13: home space segment table
 	.quad	0xc0000000		# cr14: machine check handling off
 	.quad	0			# cr15: linkage stack operations
-.Lduct: .long	0,0,0,0,0,0,0,0
-	.long	0,0,0,0,0,0,0,0
 .Lpcmsk:.quad	0x0000000180000000
 .L4malign:.quad 0xffffffffffc00000
 .Lscan2g:.quad	0x80000000 + 0x20000 - 8	# 2GB + 128K - 8
 .Lnop:	.long	0x07000700
 .Lparmaddr:
 	.quad	PARMAREA
+	.align	64
+.Lduct: .long	0,0,0,0,.Lduald,0,0,0
+	.long	0,0,0,0,0,0,0,0
+	.align	128
+.Lduald:.rept	8
+	.long	0x80000000,0,0,0	# invalid access-list entries
+	.endr
 
 	.org	0x12000
 	.globl	_ehead
diff --git a/arch/s390/kernel/ipl.c b/arch/s390/kernel/ipl.c
index 5a863a3bf10c..d125a4ead08d 100644
--- a/arch/s390/kernel/ipl.c
+++ b/arch/s390/kernel/ipl.c
@@ -1066,7 +1066,7 @@ static void do_reset_calls(void)
 		reset->fn();
 }
 
-extern __u32 dump_prefix_page;
+u32 dump_prefix_page;
 
 void s390_reset_system(void)
 {
@@ -1078,7 +1078,7 @@ void s390_reset_system(void)
 	lc->panic_stack = S390_lowcore.panic_stack;
 
 	/* Save prefix page address for dump case */
-	dump_prefix_page = (unsigned long) lc;
+	dump_prefix_page = (u32)(unsigned long) lc;
 
 	/* Disable prefixing */
 	set_prefix(0);
diff --git a/arch/s390/kernel/kprobes.c b/arch/s390/kernel/kprobes.c
index a466bab6677e..8af549e95730 100644
--- a/arch/s390/kernel/kprobes.c
+++ b/arch/s390/kernel/kprobes.c
@@ -337,21 +337,14 @@ static int __kprobes kprobe_handler(struct pt_regs *regs)
 	}
 
 	p = get_kprobe(addr);
-	if (!p) {
-		if (*addr != BREAKPOINT_INSTRUCTION) {
-			/*
-			 * The breakpoint instruction was removed right
-			 * after we hit it.  Another cpu has removed
-			 * either a probepoint or a debugger breakpoint
-			 * at this address.  In either case, no further
-			 * handling of this interrupt is appropriate.
-			 *
-			 */
-			ret = 1;
-		}
-		/* Not one of ours: let kernel handle it */
+	if (!p)
+		/*
+		 * No kprobe at this address. The fault has not been
+		 * caused by a kprobe breakpoint. The race of breakpoint
+		 * vs. kprobe remove does not exist because on s390 we
+		 * use stop_machine_run to arm/disarm the breakpoints.
+		 */
 		goto no_kprobe;
-	}
 
 	kcb->kprobe_status = KPROBE_HIT_ACTIVE;
 	set_current_kprobe(p, regs, kcb);
diff --git a/arch/s390/kernel/machine_kexec.c b/arch/s390/kernel/machine_kexec.c
index 52f57af252b4..3c77dd36994c 100644
--- a/arch/s390/kernel/machine_kexec.c
+++ b/arch/s390/kernel/machine_kexec.c
@@ -19,6 +19,7 @@
 #include <asm/system.h>
 #include <asm/smp.h>
 #include <asm/reset.h>
+#include <asm/ipl.h>
 
 typedef void (*relocate_kernel_t)(kimage_entry_t *, unsigned long);
 
@@ -29,6 +30,10 @@ int machine_kexec_prepare(struct kimage *image)
 {
 	void *reboot_code_buffer;
 
+	/* Can't replace kernel image since it is read-only. */
+	if (ipl_flags & IPL_NSS_VALID)
+		return -ENOSYS;
+
 	/* We don't support anything but the default image type for now. */
 	if (image->type != KEXEC_TYPE_DEFAULT)
 		return -EINVAL;
diff --git a/arch/s390/kernel/reipl.S b/arch/s390/kernel/reipl.S
index c3f4d9b95083..2f481cc3d1c9 100644
--- a/arch/s390/kernel/reipl.S
+++ b/arch/s390/kernel/reipl.S
@@ -8,6 +8,10 @@
 
 #include <asm/lowcore.h>
 
+#
+# do_reipl_asm
+# Parameter: r2 = schid of reipl device
+#
 		.globl	do_reipl_asm
 do_reipl_asm:	basr	%r13,0
 .Lpg0:		lpsw	.Lnewpsw-.Lpg0(%r13)
@@ -16,12 +20,12 @@ do_reipl_asm:	basr	%r13,0
 		stm	%r0,%r15,__LC_GPREGS_SAVE_AREA
 		stctl	%c0,%c15,__LC_CREGS_SAVE_AREA
 		stam	%a0,%a15,__LC_AREGS_SAVE_AREA
-		mvc	__LC_PREFIX_SAVE_AREA(4),dump_prefix_page-.Lpg0(%r13)
+		l	%r10,.Ldump_pfx-.Lpg0(%r13)
+		mvc	__LC_PREFIX_SAVE_AREA(4),0(%r10)
 		stckc	.Lclkcmp-.Lpg0(%r13)
 		mvc	__LC_CLOCK_COMP_SAVE_AREA(8),.Lclkcmp-.Lpg0(%r13)
 		stpt	__LC_CPU_TIMER_SAVE_AREA
 		st	%r13, __LC_PSW_SAVE_AREA+4
-
 		lctl	%c6,%c6,.Lall-.Lpg0(%r13)
 		lr	%r1,%r2
 		mvc	__LC_PGM_NEW_PSW(8),.Lpcnew-.Lpg0(%r13)
@@ -55,6 +59,7 @@ do_reipl_asm:	basr	%r13,0
 		.align	8
 .Lclkcmp:	.quad	0x0000000000000000
 .Lall:		.long	0xff000000
+.Ldump_pfx:	.long	dump_prefix_page
 		.align	8
 .Lnewpsw:	.long	0x00080000,0x80000000+.Lpg1
 .Lpcnew:	.long	0x00080000,0x80000000+.Lecs
@@ -79,7 +84,3 @@ do_reipl_asm:	basr	%r13,0
 		.long	0x00000000,0x00000000
 		.long	0x00000000,0x00000000
 		.long	0x00000000,0x00000000
-	.globl dump_prefix_page
-dump_prefix_page:
-	.long 0x00000000
-
diff --git a/arch/s390/kernel/reipl64.S b/arch/s390/kernel/reipl64.S
index dbb3eed38865..c41930499a5f 100644
--- a/arch/s390/kernel/reipl64.S
+++ b/arch/s390/kernel/reipl64.S
@@ -8,6 +8,12 @@
  */
 
 #include <asm/lowcore.h>
+
+#
+# do_reipl_asm
+# Parameter: r2 = schid of reipl device
+#
+
 		.globl	do_reipl_asm
 do_reipl_asm:	basr	%r13,0
 .Lpg0:		lpswe	.Lnewpsw-.Lpg0(%r13)
@@ -20,7 +26,8 @@ do_reipl_asm:	basr	%r13,0
 		stg	%r0,__LC_GPREGS_SAVE_AREA-0x1000+8(%r1)
 		stctg	%c0,%c15,__LC_CREGS_SAVE_AREA-0x1000(%r1)
 		stam	%a0,%a15,__LC_AREGS_SAVE_AREA-0x1000(%r1)
-		mvc	__LC_PREFIX_SAVE_AREA-0x1000(4,%r1),dump_prefix_page-.Lpg0(%r13)
+		lg	%r10,.Ldump_pfx-.Lpg0(%r13)
+		mvc	__LC_PREFIX_SAVE_AREA-0x1000(4,%r1),0(%r10)
 		stfpc	__LC_FP_CREG_SAVE_AREA-0x1000(%r1)
 		stckc	.Lclkcmp-.Lpg0(%r13)
 		mvc	__LC_CLOCK_COMP_SAVE_AREA-0x1000(8,%r1),.Lclkcmp-.Lpg0(%r13)
@@ -64,6 +71,7 @@ do_reipl_asm:	basr	%r13,0
 		.align	8
 .Lclkcmp:	.quad	0x0000000000000000
 .Lall:		.quad	0x00000000ff000000
+.Ldump_pfx:	.quad	dump_prefix_page
 .Lregsave:	.quad	0x0000000000000000
 		.align	16
 /*
@@ -103,6 +111,3 @@ do_reipl_asm:	basr	%r13,0
 		.long	0x00000000,0x00000000
 		.long	0x00000000,0x00000000
 		.long	0x00000000,0x00000000
-	.globl dump_prefix_page
-dump_prefix_page:
-	.long 0x00000000
diff --git a/arch/s390/kernel/smp.c b/arch/s390/kernel/smp.c
index ecaa432a99f8..97764f710bb7 100644
--- a/arch/s390/kernel/smp.c
+++ b/arch/s390/kernel/smp.c
@@ -94,10 +94,9 @@ static void __smp_call_function_map(void (*func) (void *info), void *info,
 	int cpu, local = 0;
 
 	/*
-	 * Can deadlock when interrupts are disabled or if in wrong context,
-	 * caller must disable preemption
+	 * Can deadlock when interrupts are disabled or if in wrong context.
 	 */
-	WARN_ON(irqs_disabled() || in_irq() || preemptible());
+	WARN_ON(irqs_disabled() || in_irq());
 
 	/*
 	 * Check for local function call. We have to have the same call order
@@ -152,17 +151,18 @@ out:
  * Run a function on all other CPUs.
  *
  * You must not call this function with disabled interrupts or from a
- * hardware interrupt handler. Must be called with preemption disabled.
- * You may call it from a bottom half.
+ * hardware interrupt handler. You may call it from a bottom half.
  */
 int smp_call_function(void (*func) (void *info), void *info, int nonatomic,
 		      int wait)
 {
 	cpumask_t map;
 
+	preempt_disable();
 	map = cpu_online_map;
 	cpu_clear(smp_processor_id(), map);
 	__smp_call_function_map(func, info, nonatomic, wait, map);
+	preempt_enable();
 	return 0;
 }
 EXPORT_SYMBOL(smp_call_function);
@@ -178,16 +178,17 @@ EXPORT_SYMBOL(smp_call_function);
  * Run a function on one processor.
  *
  * You must not call this function with disabled interrupts or from a
- * hardware interrupt handler. Must be called with preemption disabled.
- * You may call it from a bottom half.
+ * hardware interrupt handler. You may call it from a bottom half.
  */
 int smp_call_function_on(void (*func) (void *info), void *info, int nonatomic,
 			  int wait, int cpu)
 {
 	cpumask_t map = CPU_MASK_NONE;
 
+	preempt_disable();
 	cpu_set(cpu, map);
 	__smp_call_function_map(func, info, nonatomic, wait, map);
+	preempt_enable();
 	return 0;
 }
 EXPORT_SYMBOL(smp_call_function_on);
diff --git a/arch/s390/mm/fault.c b/arch/s390/mm/fault.c
index 641aef36ccc4..7462aebd3eb6 100644
--- a/arch/s390/mm/fault.c
+++ b/arch/s390/mm/fault.c
@@ -108,53 +108,40 @@ void bust_spinlocks(int yes)
 }
 
 /*
- * Check which address space is addressed by the access
- * register in S390_lowcore.exc_access_id.
- * Returns 1 for user space and 0 for kernel space.
+ * Returns the address space associated with the fault.
+ * Returns 0 for kernel space, 1 for user space and
+ * 2 for code execution in user space with noexec=on.
  */
-static int __check_access_register(struct pt_regs *regs, int error_code)
-{
-	int areg = S390_lowcore.exc_access_id;
-
-	if (areg == 0)
-		/* Access via access register 0 -> kernel address */
-		return 0;
-	save_access_regs(current->thread.acrs);
-	if (regs && areg < NUM_ACRS && current->thread.acrs[areg] <= 1)
-		/*
-		 * access register contains 0 -> kernel address,
-		 * access register contains 1 -> user space address
-		 */
-		return current->thread.acrs[areg];
-
-	/* Something unhealthy was done with the access registers... */
-	die("page fault via unknown access register", regs, error_code);
-	do_exit(SIGKILL);
-	return 0;
-}
-
-/*
- * Check which address space the address belongs to.
- * May return 1 or 2 for user space and 0 for kernel space.
- * Returns 2 for user space in primary addressing mode with
- * CONFIG_S390_EXEC_PROTECT on and kernel parameter noexec=on.
- */
-static inline int check_user_space(struct pt_regs *regs, int error_code)
+static inline int check_space(struct task_struct *tsk)
 {
 	/*
-	 * The lowest two bits of S390_lowcore.trans_exc_code indicate
-	 * which paging table was used:
-	 *   0: Primary Segment Table Descriptor
-	 *   1: STD determined via access register
-	 *   2: Secondary Segment Table Descriptor
-	 *   3: Home Segment Table Descriptor
+	 * The lowest two bits of S390_lowcore.trans_exc_code
+	 * indicate which paging table was used.
 	 */
-	int descriptor = S390_lowcore.trans_exc_code & 3;
-	if (unlikely(descriptor == 1))
-		return __check_access_register(regs, error_code);
-	if (descriptor == 2)
-		return current->thread.mm_segment.ar4;
-	return ((descriptor != 0) ^ (switch_amode)) << s390_noexec;
+	int desc = S390_lowcore.trans_exc_code & 3;
+
+	if (desc == 3)	/* Home Segment Table Descriptor */
+		return switch_amode == 0;
+	if (desc == 2)	/* Secondary Segment Table Descriptor */
+		return tsk->thread.mm_segment.ar4;
+#ifdef CONFIG_S390_SWITCH_AMODE
+	if (unlikely(desc == 1)) { /* STD determined via access register */
+		/* %a0 always indicates primary space. */
+		if (S390_lowcore.exc_access_id != 0) {
+			save_access_regs(tsk->thread.acrs);
+			/*
+			 * An alet of 0 indicates primary space.
+			 * An alet of 1 indicates secondary space.
+			 * Any other alet values generate an
+			 * alen-translation exception.
+			 */
+			if (tsk->thread.acrs[S390_lowcore.exc_access_id])
+				return tsk->thread.mm_segment.ar4;
+		}
+	}
+#endif
+	/* Primary Segment Table Descriptor */
+	return switch_amode << s390_noexec;
 }
 
 /*
@@ -265,16 +252,16 @@ out_fault:
  *   11       Page translation     ->  Not present       (nullification)
  *   3b       Region third trans.  ->  Not present       (nullification)
  */
-static inline void __kprobes
+static inline void
 do_exception(struct pt_regs *regs, unsigned long error_code, int is_protection)
 {
         struct task_struct *tsk;
         struct mm_struct *mm;
         struct vm_area_struct * vma;
         unsigned long address;
-	int user_address;
 	const struct exception_table_entry *fixup;
-	int si_code = SEGV_MAPERR;
+	int si_code;
+	int space;
 
         tsk = current;
         mm = tsk->mm;
@@ -294,7 +281,7 @@ do_exception(struct pt_regs *regs, unsigned long error_code, int is_protection)
 		   NULL pointer write access in kernel mode.  */
  		if (!(regs->psw.mask & PSW_MASK_PSTATE)) {
 			address = 0;
-			user_address = 0;
+			space = 0;
 			goto no_context;
 		}
 
@@ -309,15 +296,15 @@ do_exception(struct pt_regs *regs, unsigned long error_code, int is_protection)
          * the address 
          */
         address = S390_lowcore.trans_exc_code & __FAIL_ADDR_MASK;
-	user_address = check_user_space(regs, error_code);
+	space = check_space(tsk);
 
 	/*
 	 * Verify that the fault happened in user space, that
 	 * we are not in an interrupt and that there is a 
 	 * user context.
 	 */
-        if (user_address == 0 || in_atomic() || !mm)
-                goto no_context;
+	if (unlikely(space == 0 || in_atomic() || !mm))
+		goto no_context;
 
 	/*
 	 * When we get here, the fault happened in the current
@@ -328,12 +315,13 @@ do_exception(struct pt_regs *regs, unsigned long error_code, int is_protection)
 
         down_read(&mm->mmap_sem);
 
-        vma = find_vma(mm, address);
-        if (!vma)
-                goto bad_area;
+	si_code = SEGV_MAPERR;
+	vma = find_vma(mm, address);
+	if (!vma)
+		goto bad_area;
 
 #ifdef CONFIG_S390_EXEC_PROTECT
-	if (unlikely((user_address == 2) && !(vma->vm_flags & VM_EXEC)))
+	if (unlikely((space == 2) && !(vma->vm_flags & VM_EXEC)))
 		if (!signal_return(mm, regs, address, error_code))
 			/*
 			 * signal_return() has done an up_read(&mm->mmap_sem)
@@ -389,7 +377,7 @@ survive:
 	 * The instruction that caused the program check will
 	 * be repeated. Don't signal single step via SIGTRAP.
 	 */
-	clear_tsk_thread_flag(current, TIF_SINGLE_STEP);
+	clear_tsk_thread_flag(tsk, TIF_SINGLE_STEP);
         return;
 
 /*
@@ -419,7 +407,7 @@ no_context:
  * Oops. The kernel tried to access some bad page. We'll have to
  * terminate things with extreme prejudice.
  */
-        if (user_address == 0)
+	if (space == 0)
                 printk(KERN_ALERT "Unable to handle kernel pointer dereference"
         	       " at virtual kernel address %p\n", (void *)address);
         else
@@ -462,13 +450,14 @@ do_sigbus:
 		goto no_context;
 }
 
-void do_protection_exception(struct pt_regs *regs, unsigned long error_code)
+void __kprobes do_protection_exception(struct pt_regs *regs,
+				       unsigned long error_code)
 {
 	regs->psw.addr -= (error_code >> 16);
 	do_exception(regs, 4, 1);
 }
 
-void do_dat_exception(struct pt_regs *regs, unsigned long error_code)
+void __kprobes do_dat_exception(struct pt_regs *regs, unsigned long error_code)
 {
 	do_exception(regs, error_code & 0xff, 0);
 }