From 61365e132ef987f7719af5d2e434db4465957637 Mon Sep 17 00:00:00 2001
From: Martin Schwidefsky <schwidefsky@de.ibm.com>
Date: Mon, 7 Dec 2009 12:51:42 +0100
Subject: [S390] Improve address space check.

A data access in access-register mode always is a user mode access,
the code to inspect the access-registers can be removed. The second
change is to use a different test to check for no-execute fault.
The third change is to pass the translation exception identification
as parameter, in theory the trans_exc_code in the lowcore could have
been overwritten by the time the call to check_space from do_no_context
is done.

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
---
 arch/s390/mm/fault.c | 99 ++++++++++++++++++++++++----------------------------
 1 file changed, 45 insertions(+), 54 deletions(-)

(limited to 'arch/s390/mm/fault.c')

diff --git a/arch/s390/mm/fault.c b/arch/s390/mm/fault.c
index 6d507462967..3df5b918cfe 100644
--- a/arch/s390/mm/fault.c
+++ b/arch/s390/mm/fault.c
@@ -100,39 +100,28 @@ void bust_spinlocks(int yes)
 
 /*
  * 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.
+ * Returns 0 for kernel space and 1 for user space.
  */
-static inline int check_space(struct task_struct *tsk)
+static inline int user_space_fault(unsigned long trans_exc_code)
 {
 	/*
-	 * The lowest two bits of S390_lowcore.trans_exc_code
-	 * indicate which paging table was used.
+	 * The lowest two bits of the translation exception
+	 * identification indicate which paging table was used.
 	 */
-	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;
+	trans_exc_code &= 3;
+	if (trans_exc_code == 2)
+		/* Access via secondary space, set_fs setting decides */
+		return current->thread.mm_segment.ar4;
+	if (!switch_amode)
+		/* User space if the access has been done via home space. */
+		return trans_exc_code == 3;
+	/*
+	 * If the user space is not the home space the kernel runs in home
+	 * space. Access via secondary space has already been covered,
+	 * access via primary space or access register is from user space
+	 * and access via home space is from the kernel.
+	 */
+	return trans_exc_code != 3;
 }
 
 /*
@@ -162,9 +151,10 @@ static void do_sigsegv(struct pt_regs *regs, unsigned long error_code,
 }
 
 static void do_no_context(struct pt_regs *regs, unsigned long error_code,
-			  unsigned long address)
+			  unsigned long trans_exc_code)
 {
 	const struct exception_table_entry *fixup;
+	unsigned long address;
 
 	/* Are we prepared to handle this kernel fault?  */
 	fixup = search_exception_tables(regs->psw.addr & __FIXUP_MASK);
@@ -177,7 +167,8 @@ static void do_no_context(struct pt_regs *regs, unsigned long error_code,
 	 * Oops. The kernel tried to access some bad page. We'll have to
 	 * terminate things with extreme prejudice.
 	 */
-	if (check_space(current) == 0)
+	address = trans_exc_code & __FAIL_ADDR_MASK;
+	if (user_space_fault(trans_exc_code) == 0)
 		printk(KERN_ALERT "Unable to handle kernel pointer dereference"
 		       " at virtual kernel address %p\n", (void *)address);
 	else
@@ -188,7 +179,8 @@ static void do_no_context(struct pt_regs *regs, unsigned long error_code,
 	do_exit(SIGKILL);
 }
 
-static void do_low_address(struct pt_regs *regs, unsigned long error_code)
+static void do_low_address(struct pt_regs *regs, unsigned long error_code,
+			   unsigned long trans_exc_code)
 {
 	/* Low-address protection hit in kernel mode means
 	   NULL pointer write access in kernel mode.  */
@@ -198,11 +190,11 @@ static void do_low_address(struct pt_regs *regs, unsigned long error_code)
 		do_exit(SIGKILL);
 	}
 
-	do_no_context(regs, error_code, 0);
+	do_no_context(regs, error_code, trans_exc_code);
 }
 
 static void do_sigbus(struct pt_regs *regs, unsigned long error_code,
-		      unsigned long address)
+		      unsigned long trans_exc_code)
 {
 	struct task_struct *tsk = current;
 	struct mm_struct *mm = tsk->mm;
@@ -212,13 +204,13 @@ static void do_sigbus(struct pt_regs *regs, unsigned long error_code,
 	 * Send a sigbus, regardless of whether we were in kernel
 	 * or user mode.
 	 */
-	tsk->thread.prot_addr = address;
+	tsk->thread.prot_addr = trans_exc_code & __FAIL_ADDR_MASK;
 	tsk->thread.trap_no = error_code;
 	force_sig(SIGBUS, tsk);
 
 	/* Kernel mode? Handle exceptions or die */
 	if (!(regs->psw.mask & PSW_MASK_PSTATE))
-		do_no_context(regs, error_code, address);
+		do_no_context(regs, error_code, trans_exc_code);
 }
 
 #ifdef CONFIG_S390_EXEC_PROTECT
@@ -272,13 +264,13 @@ static int signal_return(struct mm_struct *mm, struct pt_regs *regs,
  *   3b       Region third trans.  ->  Not present       (nullification)
  */
 static inline void
-do_exception(struct pt_regs *regs, unsigned long error_code, int write)
+do_exception(struct pt_regs *regs, unsigned long error_code, int write,
+	     unsigned long trans_exc_code)
 {
 	struct task_struct *tsk;
 	struct mm_struct *mm;
 	struct vm_area_struct *vma;
 	unsigned long address;
-	int space;
 	int si_code;
 	int fault;
 
@@ -288,18 +280,15 @@ do_exception(struct pt_regs *regs, unsigned long error_code, int write)
 	tsk = current;
 	mm = tsk->mm;
 
-	/* get the failing address and the affected space */
-	address = S390_lowcore.trans_exc_code & __FAIL_ADDR_MASK;
-	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 (unlikely(space == 0 || in_atomic() || !mm))
+	if (unlikely(!user_space_fault(trans_exc_code) || in_atomic() || !mm))
 		goto no_context;
 
+	address = trans_exc_code & __FAIL_ADDR_MASK;
 	/*
 	 * When we get here, the fault happened in the current
 	 * task's user address space, so we can switch on the
@@ -315,7 +304,8 @@ do_exception(struct pt_regs *regs, unsigned long error_code, int write)
 		goto bad_area;
 
 #ifdef CONFIG_S390_EXEC_PROTECT
-	if (unlikely((space == 2) && !(vma->vm_flags & VM_EXEC)))
+	if (unlikely((regs->psw.mask & PSW_MASK_ASC) == PSW_ASC_SECONDARY &&
+		     (trans_exc_code & 3) == 0 && !(vma->vm_flags & VM_EXEC)))
 		if (!signal_return(mm, regs, address, error_code))
 			/*
 			 * signal_return() has done an up_read(&mm->mmap_sem)
@@ -397,12 +387,14 @@ bad_area:
 	}
 
 no_context:
-	do_no_context(regs, error_code, address);
+	do_no_context(regs, error_code, trans_exc_code);
 }
 
 void __kprobes do_protection_exception(struct pt_regs *regs,
 				       long error_code)
 {
+	unsigned long trans_exc_code = S390_lowcore.trans_exc_code;
+
 	/* Protection exception is supressing, decrement psw address. */
 	regs->psw.addr -= (error_code >> 16);
 	/*
@@ -410,31 +402,30 @@ void __kprobes do_protection_exception(struct pt_regs *regs,
 	 * as a special case because the translation exception code
 	 * field is not guaranteed to contain valid data in this case.
 	 */
-	if (unlikely(!(S390_lowcore.trans_exc_code & 4))) {
-		do_low_address(regs, error_code);
+	if (unlikely(!(trans_exc_code & 4))) {
+		do_low_address(regs, error_code, trans_exc_code);
 		return;
 	}
-	do_exception(regs, 4, 1);
+	do_exception(regs, 4, 1, trans_exc_code);
 }
 
 void __kprobes do_dat_exception(struct pt_regs *regs, long error_code)
 {
-	do_exception(regs, error_code & 0xff, 0);
+	do_exception(regs, error_code & 0xff, 0, S390_lowcore.trans_exc_code);
 }
 
 #ifdef CONFIG_64BIT
 void __kprobes do_asce_exception(struct pt_regs *regs, unsigned long error_code)
 {
+	unsigned long trans_exc_code = S390_lowcore.trans_exc_code;
 	struct mm_struct *mm;
 	struct vm_area_struct *vma;
 	unsigned long address;
-	int space;
 
 	mm = current->mm;
-	address = S390_lowcore.trans_exc_code & __FAIL_ADDR_MASK;
-	space = check_space(current);
+	address = trans_exc_code & __FAIL_ADDR_MASK;
 
-	if (unlikely(space == 0 || in_atomic() || !mm))
+	if (unlikely(!user_space_fault(trans_exc_code) || in_atomic() || !mm))
 		goto no_context;
 
 	local_irq_enable();
@@ -457,7 +448,7 @@ void __kprobes do_asce_exception(struct pt_regs *regs, unsigned long error_code)
 	}
 
 no_context:
-	do_no_context(regs, error_code, address);
+	do_no_context(regs, error_code, trans_exc_code);
 }
 #endif
 
-- 
cgit v1.2.3-70-g09d2


From b11b53342773361f3353b285eb6a3fd6074e7997 Mon Sep 17 00:00:00 2001
From: Martin Schwidefsky <schwidefsky@de.ibm.com>
Date: Mon, 7 Dec 2009 12:51:43 +0100
Subject: [S390] Improve address space mode selection.

Introduce user_mode to replace the two variables switch_amode and
s390_noexec. There are three valid combinations of the old values:
  1) switch_amode == 0 && s390_noexec == 0
  2) switch_amode == 1 && s390_noexec == 0
  3) switch_amode == 1 && s390_noexec == 1
They get replaced by
  1) user_mode == HOME_SPACE_MODE
  2) user_mode == PRIMARY_SPACE_MODE
  3) user_mode == SECONDARY_SPACE_MODE
The new kernel parameter user_mode=[primary,secondary,home] lets
you choose the address space mode the user space processes should
use. In addition the CONFIG_S390_SWITCH_AMODE config option
is removed.

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
---
 arch/s390/Kconfig                   | 15 ---------------
 arch/s390/defconfig                 |  1 -
 arch/s390/include/asm/mmu_context.h |  4 ++--
 arch/s390/include/asm/pgalloc.h     |  3 ++-
 arch/s390/include/asm/setup.h       | 17 ++++++-----------
 arch/s390/kernel/setup.c            | 36 ++++++++++++++++++++----------------
 arch/s390/kernel/vdso.c             |  9 +++++----
 arch/s390/kvm/Kconfig               |  1 -
 arch/s390/lib/uaccess_mvcos.c       |  4 ----
 arch/s390/mm/fault.c                |  4 ++--
 arch/s390/mm/pgtable.c              |  2 +-
 11 files changed, 38 insertions(+), 58 deletions(-)

(limited to 'arch/s390/mm/fault.c')

diff --git a/arch/s390/Kconfig b/arch/s390/Kconfig
index 16c673096a2..c80235206c0 100644
--- a/arch/s390/Kconfig
+++ b/arch/s390/Kconfig
@@ -220,23 +220,8 @@ config AUDIT_ARCH
 	bool
 	default y
 
-config S390_SWITCH_AMODE
-	bool "Switch kernel/user addressing modes"
-	help
-	  This option allows to switch the addressing modes of kernel and user
-	  space. The kernel parameter switch_amode=on will enable this feature,
-	  default is disabled. Enabling this (via kernel parameter) on machines
-	  earlier than IBM System z9-109 EC/BC will reduce system performance.
-
-	  Note that this option will also be selected by selecting the execute
-	  protection option below. Enabling the execute protection via the
-	  noexec kernel parameter will also switch the addressing modes,
-	  independent of the switch_amode kernel parameter.
-
-
 config S390_EXEC_PROTECT
 	bool "Data execute protection"
-	select S390_SWITCH_AMODE
 	help
 	  This option allows to enable a buffer overflow protection for user
 	  space programs and it also selects the addressing mode option above.
diff --git a/arch/s390/defconfig b/arch/s390/defconfig
index ab4464486b7..f4e53c6708d 100644
--- a/arch/s390/defconfig
+++ b/arch/s390/defconfig
@@ -185,7 +185,6 @@ CONFIG_HOTPLUG_CPU=y
 CONFIG_COMPAT=y
 CONFIG_SYSVIPC_COMPAT=y
 CONFIG_AUDIT_ARCH=y
-CONFIG_S390_SWITCH_AMODE=y
 CONFIG_S390_EXEC_PROTECT=y
 
 #
diff --git a/arch/s390/include/asm/mmu_context.h b/arch/s390/include/asm/mmu_context.h
index fc7edd6f41b..976e273988c 100644
--- a/arch/s390/include/asm/mmu_context.h
+++ b/arch/s390/include/asm/mmu_context.h
@@ -36,7 +36,7 @@ static inline int init_new_context(struct task_struct *tsk,
 		mm->context.has_pgste = 1;
 		mm->context.alloc_pgste = 1;
 	} else {
-		mm->context.noexec = s390_noexec;
+		mm->context.noexec = (user_mode == SECONDARY_SPACE_MODE);
 		mm->context.has_pgste = 0;
 		mm->context.alloc_pgste = 0;
 	}
@@ -58,7 +58,7 @@ static inline void update_mm(struct mm_struct *mm, struct task_struct *tsk)
 	pgd_t *pgd = mm->pgd;
 
 	S390_lowcore.user_asce = mm->context.asce_bits | __pa(pgd);
-	if (switch_amode) {
+	if (user_mode != HOME_SPACE_MODE) {
 		/* Load primary space page table origin. */
 		pgd = mm->context.noexec ? get_shadow_table(pgd) : pgd;
 		S390_lowcore.user_exec_asce = mm->context.asce_bits | __pa(pgd);
diff --git a/arch/s390/include/asm/pgalloc.h b/arch/s390/include/asm/pgalloc.h
index ddad5903341..68940d0bad9 100644
--- a/arch/s390/include/asm/pgalloc.h
+++ b/arch/s390/include/asm/pgalloc.h
@@ -143,7 +143,8 @@ static inline pgd_t *pgd_alloc(struct mm_struct *mm)
 	spin_lock_init(&mm->context.list_lock);
 	INIT_LIST_HEAD(&mm->context.crst_list);
 	INIT_LIST_HEAD(&mm->context.pgtable_list);
-	return (pgd_t *) crst_table_alloc(mm, s390_noexec);
+	return (pgd_t *)
+		crst_table_alloc(mm, user_mode == SECONDARY_SPACE_MODE);
 }
 #define pgd_free(mm, pgd) crst_table_free(mm, (unsigned long *) pgd)
 
diff --git a/arch/s390/include/asm/setup.h b/arch/s390/include/asm/setup.h
index e37478e8728..52a779c337e 100644
--- a/arch/s390/include/asm/setup.h
+++ b/arch/s390/include/asm/setup.h
@@ -49,17 +49,12 @@ extern unsigned long memory_end;
 
 void detect_memory_layout(struct mem_chunk chunk[]);
 
-#ifdef CONFIG_S390_SWITCH_AMODE
-extern unsigned int switch_amode;
-#else
-#define switch_amode	(0)
-#endif
-
-#ifdef CONFIG_S390_EXEC_PROTECT
-extern unsigned int s390_noexec;
-#else
-#define s390_noexec	(0)
-#endif
+#define PRIMARY_SPACE_MODE	0
+#define ACCESS_REGISTER_MODE	1
+#define SECONDARY_SPACE_MODE	2
+#define HOME_SPACE_MODE		3
+
+extern unsigned int user_mode;
 
 /*
  * Machine features detected in head.S
diff --git a/arch/s390/kernel/setup.c b/arch/s390/kernel/setup.c
index 061479ff029..0663287fa1b 100644
--- a/arch/s390/kernel/setup.c
+++ b/arch/s390/kernel/setup.c
@@ -305,9 +305,8 @@ static int __init early_parse_mem(char *p)
 }
 early_param("mem", early_parse_mem);
 
-#ifdef CONFIG_S390_SWITCH_AMODE
-unsigned int switch_amode = 0;
-EXPORT_SYMBOL_GPL(switch_amode);
+unsigned int user_mode = HOME_SPACE_MODE;
+EXPORT_SYMBOL_GPL(user_mode);
 
 static int set_amode_and_uaccess(unsigned long user_amode,
 				 unsigned long user32_amode)
@@ -340,23 +339,29 @@ static int set_amode_and_uaccess(unsigned long user_amode,
  */
 static int __init early_parse_switch_amode(char *p)
 {
-	switch_amode = 1;
+	if (user_mode != SECONDARY_SPACE_MODE)
+		user_mode = PRIMARY_SPACE_MODE;
 	return 0;
 }
 early_param("switch_amode", early_parse_switch_amode);
 
-#else /* CONFIG_S390_SWITCH_AMODE */
-static inline int set_amode_and_uaccess(unsigned long user_amode,
-					unsigned long user32_amode)
+static int __init early_parse_user_mode(char *p)
 {
+	if (p && strcmp(p, "primary") == 0)
+		user_mode = PRIMARY_SPACE_MODE;
+#ifdef CONFIG_S390_EXEC_PROTECT
+	else if (p && strcmp(p, "secondary") == 0)
+		user_mode = SECONDARY_SPACE_MODE;
+#endif
+	else if (!p || strcmp(p, "home") == 0)
+		user_mode = HOME_SPACE_MODE;
+	else
+		return 1;
 	return 0;
 }
-#endif /* CONFIG_S390_SWITCH_AMODE */
+early_param("user_mode", early_parse_user_mode);
 
 #ifdef CONFIG_S390_EXEC_PROTECT
-unsigned int s390_noexec = 0;
-EXPORT_SYMBOL_GPL(s390_noexec);
-
 /*
  * Enable execute protection?
  */
@@ -364,8 +369,7 @@ static int __init early_parse_noexec(char *p)
 {
 	if (!strncmp(p, "off", 3))
 		return 0;
-	switch_amode = 1;
-	s390_noexec = 1;
+	user_mode = SECONDARY_SPACE_MODE;
 	return 0;
 }
 early_param("noexec", early_parse_noexec);
@@ -373,7 +377,7 @@ early_param("noexec", early_parse_noexec);
 
 static void setup_addressing_mode(void)
 {
-	if (s390_noexec) {
+	if (user_mode == SECONDARY_SPACE_MODE) {
 		if (set_amode_and_uaccess(PSW_ASC_SECONDARY,
 					  PSW32_ASC_SECONDARY))
 			pr_info("Execute protection active, "
@@ -381,7 +385,7 @@ static void setup_addressing_mode(void)
 		else
 			pr_info("Execute protection active, "
 				"mvcos not available\n");
-	} else if (switch_amode) {
+	} else if (user_mode == PRIMARY_SPACE_MODE) {
 		if (set_amode_and_uaccess(PSW_ASC_PRIMARY, PSW32_ASC_PRIMARY))
 			pr_info("Address spaces switched, "
 				"mvcos available\n");
@@ -411,7 +415,7 @@ setup_lowcore(void)
 	lc->restart_psw.mask = PSW_BASE_BITS | PSW_DEFAULT_KEY;
 	lc->restart_psw.addr =
 		PSW_ADDR_AMODE | (unsigned long) restart_int_handler;
-	if (switch_amode)
+	if (user_mode != HOME_SPACE_MODE)
 		lc->restart_psw.mask |= PSW_ASC_HOME;
 	lc->external_new_psw.mask = psw_kernel_bits;
 	lc->external_new_psw.addr =
diff --git a/arch/s390/kernel/vdso.c b/arch/s390/kernel/vdso.c
index adfb32aa6d5..5f99e66c51c 100644
--- a/arch/s390/kernel/vdso.c
+++ b/arch/s390/kernel/vdso.c
@@ -86,7 +86,8 @@ static void vdso_init_data(struct vdso_data *vd)
 	unsigned int facility_list;
 
 	facility_list = stfl();
-	vd->ectg_available = switch_amode && (facility_list & 1);
+	vd->ectg_available =
+		user_mode != HOME_SPACE_MODE && (facility_list & 1);
 }
 
 #ifdef CONFIG_64BIT
@@ -114,7 +115,7 @@ int vdso_alloc_per_cpu(int cpu, struct _lowcore *lowcore)
 
 	lowcore->vdso_per_cpu_data = __LC_PASTE;
 
-	if (!switch_amode || !vdso_enabled)
+	if (user_mode == HOME_SPACE_MODE || !vdso_enabled)
 		return 0;
 
 	segment_table = __get_free_pages(GFP_KERNEL, SEGMENT_ORDER);
@@ -160,7 +161,7 @@ void vdso_free_per_cpu(int cpu, struct _lowcore *lowcore)
 	unsigned long segment_table, page_table, page_frame;
 	u32 *psal, *aste;
 
-	if (!switch_amode || !vdso_enabled)
+	if (user_mode == HOME_SPACE_MODE || !vdso_enabled)
 		return;
 
 	psal = (u32 *)(addr_t) lowcore->paste[4];
@@ -184,7 +185,7 @@ static void __vdso_init_cr5(void *dummy)
 
 static void vdso_init_cr5(void)
 {
-	if (switch_amode && vdso_enabled)
+	if (user_mode != HOME_SPACE_MODE && vdso_enabled)
 		on_each_cpu(__vdso_init_cr5, NULL, 1);
 }
 #endif /* CONFIG_64BIT */
diff --git a/arch/s390/kvm/Kconfig b/arch/s390/kvm/Kconfig
index bf164fc2186..6ee55ae84ce 100644
--- a/arch/s390/kvm/Kconfig
+++ b/arch/s390/kvm/Kconfig
@@ -20,7 +20,6 @@ config KVM
 	depends on HAVE_KVM && EXPERIMENTAL
 	select PREEMPT_NOTIFIERS
 	select ANON_INODES
-	select S390_SWITCH_AMODE
 	---help---
 	  Support hosting paravirtualized guest machines using the SIE
 	  virtualization capability on the mainframe. This should work
diff --git a/arch/s390/lib/uaccess_mvcos.c b/arch/s390/lib/uaccess_mvcos.c
index 58da3f46121..60455f104ea 100644
--- a/arch/s390/lib/uaccess_mvcos.c
+++ b/arch/s390/lib/uaccess_mvcos.c
@@ -162,7 +162,6 @@ static size_t clear_user_mvcos(size_t size, void __user *to)
 	return size;
 }
 
-#ifdef CONFIG_S390_SWITCH_AMODE
 static size_t strnlen_user_mvcos(size_t count, const char __user *src)
 {
 	char buf[256];
@@ -200,7 +199,6 @@ static size_t strncpy_from_user_mvcos(size_t count, const char __user *src,
 	} while ((len_str == len) && (done < count));
 	return done;
 }
-#endif /* CONFIG_S390_SWITCH_AMODE */
 
 struct uaccess_ops uaccess_mvcos = {
 	.copy_from_user = copy_from_user_mvcos_check,
@@ -215,7 +213,6 @@ struct uaccess_ops uaccess_mvcos = {
 	.futex_atomic_cmpxchg = futex_atomic_cmpxchg_std,
 };
 
-#ifdef CONFIG_S390_SWITCH_AMODE
 struct uaccess_ops uaccess_mvcos_switch = {
 	.copy_from_user = copy_from_user_mvcos,
 	.copy_from_user_small = copy_from_user_mvcos,
@@ -228,4 +225,3 @@ struct uaccess_ops uaccess_mvcos_switch = {
 	.futex_atomic_op = futex_atomic_op_pt,
 	.futex_atomic_cmpxchg = futex_atomic_cmpxchg_pt,
 };
-#endif
diff --git a/arch/s390/mm/fault.c b/arch/s390/mm/fault.c
index 3df5b918cfe..77108e34fc1 100644
--- a/arch/s390/mm/fault.c
+++ b/arch/s390/mm/fault.c
@@ -112,7 +112,7 @@ static inline int user_space_fault(unsigned long trans_exc_code)
 	if (trans_exc_code == 2)
 		/* Access via secondary space, set_fs setting decides */
 		return current->thread.mm_segment.ar4;
-	if (!switch_amode)
+	if (user_mode == HOME_SPACE_MODE)
 		/* User space if the access has been done via home space. */
 		return trans_exc_code == 3;
 	/*
@@ -168,7 +168,7 @@ static void do_no_context(struct pt_regs *regs, unsigned long error_code,
 	 * terminate things with extreme prejudice.
 	 */
 	address = trans_exc_code & __FAIL_ADDR_MASK;
-	if (user_space_fault(trans_exc_code) == 0)
+	if (!user_space_fault(trans_exc_code))
 		printk(KERN_ALERT "Unable to handle kernel pointer dereference"
 		       " at virtual kernel address %p\n", (void *)address);
 	else
diff --git a/arch/s390/mm/pgtable.c b/arch/s390/mm/pgtable.c
index 2757c5616a0..ad621e06ada 100644
--- a/arch/s390/mm/pgtable.c
+++ b/arch/s390/mm/pgtable.c
@@ -269,7 +269,7 @@ int s390_enable_sie(void)
 	struct mm_struct *mm, *old_mm;
 
 	/* Do we have switched amode? If no, we cannot do sie */
-	if (!switch_amode)
+	if (user_mode == HOME_SPACE_MODE)
 		return -EINVAL;
 
 	/* Do we have pgstes? if yes, we are done */
-- 
cgit v1.2.3-70-g09d2


From 7ecb344ae80bc03397ded3b004e06ecfe32becf9 Mon Sep 17 00:00:00 2001
From: Martin Schwidefsky <schwidefsky@de.ibm.com>
Date: Mon, 7 Dec 2009 12:51:44 +0100
Subject: [S390] Improve notify_page_fault implementation.

notify_page_fault does a preempt_disable/preempt_enable for each
fault generated by a kernel access to user space. If kprobes
is not active that is unnecessary since the interrupts are not
reenabled yet. To play safe repeat the kprobe_running check after
preempt_disable().

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
---
 arch/s390/mm/fault.c | 14 ++++----------
 1 file changed, 4 insertions(+), 10 deletions(-)

(limited to 'arch/s390/mm/fault.c')

diff --git a/arch/s390/mm/fault.c b/arch/s390/mm/fault.c
index 77108e34fc1..fd72c269cdb 100644
--- a/arch/s390/mm/fault.c
+++ b/arch/s390/mm/fault.c
@@ -52,11 +52,11 @@
 extern int sysctl_userprocess_debug;
 #endif
 
-#ifdef CONFIG_KPROBES
-static inline int notify_page_fault(struct pt_regs *regs, long err)
+static inline int notify_page_fault(struct pt_regs *regs)
 {
 	int ret = 0;
 
+#ifdef CONFIG_KPROBES
 	/* kprobe_running() needs smp_processor_id() */
 	if (!user_mode(regs)) {
 		preempt_disable();
@@ -64,15 +64,9 @@ static inline int notify_page_fault(struct pt_regs *regs, long err)
 			ret = 1;
 		preempt_enable();
 	}
-
+#endif
 	return ret;
 }
-#else
-static inline int notify_page_fault(struct pt_regs *regs, long err)
-{
-	return 0;
-}
-#endif
 
 
 /*
@@ -274,7 +268,7 @@ do_exception(struct pt_regs *regs, unsigned long error_code, int write,
 	int si_code;
 	int fault;
 
-	if (notify_page_fault(regs, error_code))
+	if (notify_page_fault(regs))
 		return;
 
 	tsk = current;
-- 
cgit v1.2.3-70-g09d2


From 50d7280d430484a890ddcadc7f738b5b6dd28bf1 Mon Sep 17 00:00:00 2001
From: Martin Schwidefsky <schwidefsky@de.ibm.com>
Date: Mon, 7 Dec 2009 12:51:45 +0100
Subject: [S390] fault handler performance optimization.

Slim down the do_exception function to handle only the fast path of a
fault and move the exceptional cases into a new function. That slightly
increases the performance of the fault handling.

Build fix for !CONFIG_COMPAT by
Kamalesh Babulal <kamalesh@linux.vnet.ibm.com>

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
---
 arch/s390/mm/fault.c | 258 +++++++++++++++++++++++++--------------------------
 1 file changed, 129 insertions(+), 129 deletions(-)

(limited to 'arch/s390/mm/fault.c')

diff --git a/arch/s390/mm/fault.c b/arch/s390/mm/fault.c
index fd72c269cdb..0dcfcfb5b5b 100644
--- a/arch/s390/mm/fault.c
+++ b/arch/s390/mm/fault.c
@@ -34,16 +34,15 @@
 #include <asm/pgtable.h>
 #include <asm/s390_ext.h>
 #include <asm/mmu_context.h>
+#include <asm/compat.h>
 #include "../kernel/entry.h"
 
 #ifndef CONFIG_64BIT
 #define __FAIL_ADDR_MASK 0x7ffff000
-#define __FIXUP_MASK 0x7fffffff
 #define __SUBCODE_MASK 0x0200
 #define __PF_RES_FIELD 0ULL
 #else /* CONFIG_64BIT */
 #define __FAIL_ADDR_MASK -4096L
-#define __FIXUP_MASK ~0L
 #define __SUBCODE_MASK 0x0600
 #define __PF_RES_FIELD 0x8000000000000000ULL
 #endif /* CONFIG_64BIT */
@@ -52,6 +51,10 @@
 extern int sysctl_userprocess_debug;
 #endif
 
+#define VM_FAULT_BADCONTEXT	0x010000
+#define VM_FAULT_BADMAP		0x020000
+#define VM_FAULT_BADACCESS	0x040000
+
 static inline int notify_page_fault(struct pt_regs *regs)
 {
 	int ret = 0;
@@ -122,18 +125,22 @@ static inline int user_space_fault(unsigned long trans_exc_code)
  * Send SIGSEGV to task.  This is an external routine
  * to keep the stack usage of do_page_fault small.
  */
-static void do_sigsegv(struct pt_regs *regs, unsigned long error_code,
-		       int si_code, unsigned long address)
+static noinline void do_sigsegv(struct pt_regs *regs, long int_code,
+				int si_code, unsigned long trans_exc_code)
 {
 	struct siginfo si;
+	unsigned long address;
 
+	address = trans_exc_code & __FAIL_ADDR_MASK;
+	current->thread.prot_addr = address;
+	current->thread.trap_no = int_code;
 #if defined(CONFIG_SYSCTL) || defined(CONFIG_PROCESS_DEBUG)
 #if defined(CONFIG_SYSCTL)
 	if (sysctl_userprocess_debug)
 #endif
 	{
 		printk("User process fault: interruption code 0x%lX\n",
-		       error_code);
+		       int_code);
 		printk("failing address: %lX\n", address);
 		show_regs(regs);
 	}
@@ -144,14 +151,14 @@ static void do_sigsegv(struct pt_regs *regs, unsigned long error_code,
 	force_sig_info(SIGSEGV, &si, current);
 }
 
-static void do_no_context(struct pt_regs *regs, unsigned long error_code,
-			  unsigned long trans_exc_code)
+static noinline void do_no_context(struct pt_regs *regs, long int_code,
+				   unsigned long trans_exc_code)
 {
 	const struct exception_table_entry *fixup;
 	unsigned long address;
 
 	/* Are we prepared to handle this kernel fault?  */
-	fixup = search_exception_tables(regs->psw.addr & __FIXUP_MASK);
+	fixup = search_exception_tables(regs->psw.addr & PSW_ADDR_INSN);
 	if (fixup) {
 		regs->psw.addr = fixup->fixup | PSW_ADDR_AMODE;
 		return;
@@ -169,107 +176,127 @@ static void do_no_context(struct pt_regs *regs, unsigned long error_code,
 		printk(KERN_ALERT "Unable to handle kernel paging request"
 		       " at virtual user address %p\n", (void *)address);
 
-	die("Oops", regs, error_code);
+	die("Oops", regs, int_code);
 	do_exit(SIGKILL);
 }
 
-static void do_low_address(struct pt_regs *regs, unsigned long error_code,
-			   unsigned long trans_exc_code)
+static noinline void do_low_address(struct pt_regs *regs, long int_code,
+				    unsigned long trans_exc_code)
 {
 	/* Low-address protection hit in kernel mode means
 	   NULL pointer write access in kernel mode.  */
 	if (regs->psw.mask & PSW_MASK_PSTATE) {
 		/* Low-address protection hit in user mode 'cannot happen'. */
-		die ("Low-address protection", regs, error_code);
+		die ("Low-address protection", regs, int_code);
 		do_exit(SIGKILL);
 	}
 
-	do_no_context(regs, error_code, trans_exc_code);
+	do_no_context(regs, int_code, trans_exc_code);
 }
 
-static void do_sigbus(struct pt_regs *regs, unsigned long error_code,
-		      unsigned long trans_exc_code)
+static noinline void do_sigbus(struct pt_regs *regs, long int_code,
+			       unsigned long trans_exc_code)
 {
 	struct task_struct *tsk = current;
-	struct mm_struct *mm = tsk->mm;
 
-	up_read(&mm->mmap_sem);
 	/*
 	 * Send a sigbus, regardless of whether we were in kernel
 	 * or user mode.
 	 */
 	tsk->thread.prot_addr = trans_exc_code & __FAIL_ADDR_MASK;
-	tsk->thread.trap_no = error_code;
+	tsk->thread.trap_no = int_code;
 	force_sig(SIGBUS, tsk);
-
-	/* Kernel mode? Handle exceptions or die */
-	if (!(regs->psw.mask & PSW_MASK_PSTATE))
-		do_no_context(regs, error_code, trans_exc_code);
 }
 
 #ifdef CONFIG_S390_EXEC_PROTECT
-static int signal_return(struct mm_struct *mm, struct pt_regs *regs,
-			 unsigned long address, unsigned long error_code)
+static noinline int signal_return(struct pt_regs *regs, long int_code,
+				  unsigned long trans_exc_code)
 {
 	u16 instruction;
 	int rc;
-#ifdef CONFIG_COMPAT
-	int compat;
-#endif
 
-	pagefault_disable();
 	rc = __get_user(instruction, (u16 __user *) regs->psw.addr);
-	pagefault_enable();
-	if (rc)
-		return -EFAULT;
 
-	up_read(&mm->mmap_sem);
-	clear_tsk_thread_flag(current, TIF_SINGLE_STEP);
-#ifdef CONFIG_COMPAT
-	compat = is_compat_task();
-	if (compat && instruction == 0x0a77)
-		sys32_sigreturn();
-	else if (compat && instruction == 0x0aad)
-		sys32_rt_sigreturn();
-	else
-#endif
-	if (instruction == 0x0a77)
-		sys_sigreturn();
-	else if (instruction == 0x0aad)
-		sys_rt_sigreturn();
-	else {
-		current->thread.prot_addr = address;
-		current->thread.trap_no = error_code;
-		do_sigsegv(regs, error_code, SEGV_MAPERR, address);
-	}
+	if (!rc && instruction == 0x0a77) {
+		clear_tsk_thread_flag(current, TIF_SINGLE_STEP);
+		if (is_compat_task())
+			sys32_sigreturn();
+		else
+			sys_sigreturn();
+	} else if (!rc && instruction == 0x0aad) {
+		clear_tsk_thread_flag(current, TIF_SINGLE_STEP);
+		if (is_compat_task())
+			sys32_rt_sigreturn();
+		else
+			sys_rt_sigreturn();
+	} else
+		do_sigsegv(regs, int_code, SEGV_MAPERR, trans_exc_code);
 	return 0;
 }
 #endif /* CONFIG_S390_EXEC_PROTECT */
 
+static noinline void do_fault_error(struct pt_regs *regs, long int_code,
+				    unsigned long trans_exc_code, int fault)
+{
+	int si_code;
+
+	switch (fault) {
+	case VM_FAULT_BADACCESS:
+#ifdef CONFIG_S390_EXEC_PROTECT
+		if ((regs->psw.mask & PSW_MASK_ASC) == PSW_ASC_SECONDARY &&
+		    (trans_exc_code & 3) == 0) {
+			signal_return(regs, int_code, trans_exc_code);
+			break;
+		}
+#endif /* CONFIG_S390_EXEC_PROTECT */
+	case VM_FAULT_BADMAP:
+		/* Bad memory access. Check if it is kernel or user space. */
+		if (regs->psw.mask & PSW_MASK_PSTATE) {
+			/* User mode accesses just cause a SIGSEGV */
+			si_code = (fault == VM_FAULT_BADMAP) ?
+				SEGV_MAPERR : SEGV_ACCERR;
+			do_sigsegv(regs, int_code, si_code, trans_exc_code);
+			return;
+		}
+	case VM_FAULT_BADCONTEXT:
+		do_no_context(regs, int_code, trans_exc_code);
+		break;
+	default: /* fault & VM_FAULT_ERROR */
+		if (fault & VM_FAULT_OOM)
+			pagefault_out_of_memory();
+		else if (fault & VM_FAULT_SIGBUS) {
+			do_sigbus(regs, int_code, trans_exc_code);
+			/* Kernel mode? Handle exceptions or die */
+			if (!(regs->psw.mask & PSW_MASK_PSTATE))
+				do_no_context(regs, int_code, trans_exc_code);
+		} else
+			BUG();
+		break;
+	}
+}
+
 /*
  * This routine handles page faults.  It determines the address,
  * and the problem, and then passes it off to one of the appropriate
  * routines.
  *
- * error_code:
+ * interruption code (int_code):
  *   04       Protection           ->  Write-Protection  (suprression)
  *   10       Segment translation  ->  Not present       (nullification)
  *   11       Page translation     ->  Not present       (nullification)
  *   3b       Region third trans.  ->  Not present       (nullification)
  */
-static inline void
-do_exception(struct pt_regs *regs, unsigned long error_code, int write,
-	     unsigned long trans_exc_code)
+static inline int do_exception(struct pt_regs *regs, int write,
+			       unsigned long trans_exc_code)
 {
 	struct task_struct *tsk;
 	struct mm_struct *mm;
 	struct vm_area_struct *vma;
 	unsigned long address;
-	int si_code;
 	int fault;
 
 	if (notify_page_fault(regs))
-		return;
+		return 0;
 
 	tsk = current;
 	mm = tsk->mm;
@@ -279,8 +306,9 @@ do_exception(struct pt_regs *regs, unsigned long error_code, int write,
 	 * we are not in an interrupt and that there is a 
 	 * user context.
 	 */
+	fault = VM_FAULT_BADCONTEXT;
 	if (unlikely(!user_space_fault(trans_exc_code) || in_atomic() || !mm))
-		goto no_context;
+		goto out;
 
 	address = trans_exc_code & __FAIL_ADDR_MASK;
 	/*
@@ -292,41 +320,35 @@ do_exception(struct pt_regs *regs, unsigned long error_code, int write,
 	perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS, 1, 0, regs, address);
 	down_read(&mm->mmap_sem);
 
-	si_code = SEGV_MAPERR;
+	fault = VM_FAULT_BADMAP;
 	vma = find_vma(mm, address);
 	if (!vma)
-		goto bad_area;
+		goto out_up;
 
+	if (unlikely(vma->vm_start > address)) {
+		if (!(vma->vm_flags & VM_GROWSDOWN))
+			goto out_up;
+		if (expand_stack(vma, address))
+			goto out_up;
+	}
+
+	/*
+	 * Ok, we have a good vm_area for this memory access, so
+	 * we can handle it..
+	 */
+	fault = VM_FAULT_BADACCESS;
 #ifdef CONFIG_S390_EXEC_PROTECT
 	if (unlikely((regs->psw.mask & PSW_MASK_ASC) == PSW_ASC_SECONDARY &&
 		     (trans_exc_code & 3) == 0 && !(vma->vm_flags & VM_EXEC)))
-		if (!signal_return(mm, regs, address, error_code))
-			/*
-			 * signal_return() has done an up_read(&mm->mmap_sem)
-			 * if it returns 0.
-			 */
-			return;
+		goto out_up;
 #endif
-
-	if (vma->vm_start <= address)
-		goto good_area;
-	if (!(vma->vm_flags & VM_GROWSDOWN))
-		goto bad_area;
-	if (expand_stack(vma, address))
-		goto bad_area;
-/*
- * Ok, we have a good vm_area for this memory access, so
- * we can handle it..
- */
-good_area:
-	si_code = SEGV_ACCERR;
 	if (!write) {
 		/* page not present, check vm flags */
 		if (!(vma->vm_flags & (VM_READ | VM_EXEC | VM_WRITE)))
-			goto bad_area;
+			goto out_up;
 	} else {
 		if (!(vma->vm_flags & VM_WRITE))
-			goto bad_area;
+			goto out_up;
 	}
 
 	if (is_vm_hugetlb_page(vma))
@@ -337,17 +359,9 @@ good_area:
 	 * the fault.
 	 */
 	fault = handle_mm_fault(mm, vma, address, write ? FAULT_FLAG_WRITE : 0);
-	if (unlikely(fault & VM_FAULT_ERROR)) {
-		if (fault & VM_FAULT_OOM) {
-			up_read(&mm->mmap_sem);
-			pagefault_out_of_memory();
-			return;
-		} else if (fault & VM_FAULT_SIGBUS) {
-			do_sigbus(regs, error_code, address);
-			return;
-		}
-		BUG();
-	}
+	if (unlikely(fault & VM_FAULT_ERROR))
+		goto out_up;
+
 	if (fault & VM_FAULT_MAJOR) {
 		tsk->maj_flt++;
 		perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS_MAJ, 1, 0,
@@ -357,67 +371,55 @@ good_area:
 		perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS_MIN, 1, 0,
 				     regs, address);
 	}
-        up_read(&mm->mmap_sem);
 	/*
 	 * The instruction that caused the program check will
 	 * be repeated. Don't signal single step via SIGTRAP.
 	 */
 	clear_tsk_thread_flag(tsk, TIF_SINGLE_STEP);
-        return;
-
-/*
- * Something tried to access memory that isn't in our memory map..
- * Fix it, but check if it's kernel or user first..
- */
-bad_area:
+	fault = 0;
+out_up:
 	up_read(&mm->mmap_sem);
-
-	/* User mode accesses just cause a SIGSEGV */
-	if (regs->psw.mask & PSW_MASK_PSTATE) {
-		tsk->thread.prot_addr = address;
-		tsk->thread.trap_no = error_code;
-		do_sigsegv(regs, error_code, si_code, address);
-		return;
-	}
-
-no_context:
-	do_no_context(regs, error_code, trans_exc_code);
+out:
+	return fault;
 }
 
-void __kprobes do_protection_exception(struct pt_regs *regs,
-				       long error_code)
+void __kprobes do_protection_exception(struct pt_regs *regs, long int_code)
 {
 	unsigned long trans_exc_code = S390_lowcore.trans_exc_code;
+	int fault;
 
 	/* Protection exception is supressing, decrement psw address. */
-	regs->psw.addr -= (error_code >> 16);
+	regs->psw.addr -= (int_code >> 16);
 	/*
 	 * Check for low-address protection.  This needs to be treated
 	 * as a special case because the translation exception code
 	 * field is not guaranteed to contain valid data in this case.
 	 */
 	if (unlikely(!(trans_exc_code & 4))) {
-		do_low_address(regs, error_code, trans_exc_code);
+		do_low_address(regs, int_code, trans_exc_code);
 		return;
 	}
-	do_exception(regs, 4, 1, trans_exc_code);
+	fault = do_exception(regs, 1, trans_exc_code);
+	if (unlikely(fault))
+		do_fault_error(regs, 4, trans_exc_code, fault);
 }
 
-void __kprobes do_dat_exception(struct pt_regs *regs, long error_code)
+void __kprobes do_dat_exception(struct pt_regs *regs, long int_code)
 {
-	do_exception(regs, error_code & 0xff, 0, S390_lowcore.trans_exc_code);
+	unsigned long trans_exc_code = S390_lowcore.trans_exc_code;
+	int fault;
+
+	fault = do_exception(regs, 0, trans_exc_code);
+	if (unlikely(fault))
+		do_fault_error(regs, int_code & 255, trans_exc_code, fault);
 }
 
 #ifdef CONFIG_64BIT
-void __kprobes do_asce_exception(struct pt_regs *regs, unsigned long error_code)
+void __kprobes do_asce_exception(struct pt_regs *regs, long int_code)
 {
 	unsigned long trans_exc_code = S390_lowcore.trans_exc_code;
-	struct mm_struct *mm;
+	struct mm_struct *mm = current->mm;
 	struct vm_area_struct *vma;
-	unsigned long address;
-
-	mm = current->mm;
-	address = trans_exc_code & __FAIL_ADDR_MASK;
 
 	if (unlikely(!user_space_fault(trans_exc_code) || in_atomic() || !mm))
 		goto no_context;
@@ -425,7 +427,7 @@ void __kprobes do_asce_exception(struct pt_regs *regs, unsigned long error_code)
 	local_irq_enable();
 
 	down_read(&mm->mmap_sem);
-	vma = find_vma(mm, address);
+	vma = find_vma(mm, trans_exc_code & __FAIL_ADDR_MASK);
 	up_read(&mm->mmap_sem);
 
 	if (vma) {
@@ -435,14 +437,12 @@ void __kprobes do_asce_exception(struct pt_regs *regs, unsigned long error_code)
 
 	/* User mode accesses just cause a SIGSEGV */
 	if (regs->psw.mask & PSW_MASK_PSTATE) {
-		current->thread.prot_addr = address;
-		current->thread.trap_no = error_code;
-		do_sigsegv(regs, error_code, SEGV_MAPERR, address);
+		do_sigsegv(regs, int_code, SEGV_MAPERR, trans_exc_code);
 		return;
 	}
 
 no_context:
-	do_no_context(regs, error_code, trans_exc_code);
+	do_no_context(regs, int_code, trans_exc_code);
 }
 #endif
 
@@ -507,7 +507,7 @@ void pfault_fini(void)
 		: : "a" (&refbk), "m" (refbk) : "cc");
 }
 
-static void pfault_interrupt(__u16 error_code)
+static void pfault_interrupt(__u16 int_code)
 {
 	struct task_struct *tsk;
 	__u16 subcode;
-- 
cgit v1.2.3-70-g09d2


From 1ab947de293f43812276b60cf9fa21127e7a5bb2 Mon Sep 17 00:00:00 2001
From: Martin Schwidefsky <schwidefsky@de.ibm.com>
Date: Mon, 7 Dec 2009 12:51:46 +0100
Subject: [S390] fault handler access flags check.

Simplify the check of the vma->flags in do_exception for the
different fault types.

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
---
 arch/s390/mm/fault.c | 30 +++++++++++++-----------------
 1 file changed, 13 insertions(+), 17 deletions(-)

(limited to 'arch/s390/mm/fault.c')

diff --git a/arch/s390/mm/fault.c b/arch/s390/mm/fault.c
index 0dcfcfb5b5b..5a9e9a77dc1 100644
--- a/arch/s390/mm/fault.c
+++ b/arch/s390/mm/fault.c
@@ -286,7 +286,7 @@ static noinline void do_fault_error(struct pt_regs *regs, long int_code,
  *   11       Page translation     ->  Not present       (nullification)
  *   3b       Region third trans.  ->  Not present       (nullification)
  */
-static inline int do_exception(struct pt_regs *regs, int write,
+static inline int do_exception(struct pt_regs *regs, int access,
 			       unsigned long trans_exc_code)
 {
 	struct task_struct *tsk;
@@ -337,19 +337,8 @@ static inline int do_exception(struct pt_regs *regs, int write,
 	 * we can handle it..
 	 */
 	fault = VM_FAULT_BADACCESS;
-#ifdef CONFIG_S390_EXEC_PROTECT
-	if (unlikely((regs->psw.mask & PSW_MASK_ASC) == PSW_ASC_SECONDARY &&
-		     (trans_exc_code & 3) == 0 && !(vma->vm_flags & VM_EXEC)))
+	if (unlikely(!(vma->vm_flags & access)))
 		goto out_up;
-#endif
-	if (!write) {
-		/* page not present, check vm flags */
-		if (!(vma->vm_flags & (VM_READ | VM_EXEC | VM_WRITE)))
-			goto out_up;
-	} else {
-		if (!(vma->vm_flags & VM_WRITE))
-			goto out_up;
-	}
 
 	if (is_vm_hugetlb_page(vma))
 		address &= HPAGE_MASK;
@@ -358,7 +347,8 @@ static inline int do_exception(struct pt_regs *regs, int write,
 	 * make sure we exit gracefully rather than endlessly redo
 	 * the fault.
 	 */
-	fault = handle_mm_fault(mm, vma, address, write ? FAULT_FLAG_WRITE : 0);
+	fault = handle_mm_fault(mm, vma, address,
+				(access == VM_WRITE) ? FAULT_FLAG_WRITE : 0);
 	if (unlikely(fault & VM_FAULT_ERROR))
 		goto out_up;
 
@@ -399,7 +389,7 @@ void __kprobes do_protection_exception(struct pt_regs *regs, long int_code)
 		do_low_address(regs, int_code, trans_exc_code);
 		return;
 	}
-	fault = do_exception(regs, 1, trans_exc_code);
+	fault = do_exception(regs, VM_WRITE, trans_exc_code);
 	if (unlikely(fault))
 		do_fault_error(regs, 4, trans_exc_code, fault);
 }
@@ -407,9 +397,15 @@ void __kprobes do_protection_exception(struct pt_regs *regs, long int_code)
 void __kprobes do_dat_exception(struct pt_regs *regs, long int_code)
 {
 	unsigned long trans_exc_code = S390_lowcore.trans_exc_code;
-	int fault;
+	int access, fault;
 
-	fault = do_exception(regs, 0, trans_exc_code);
+	access = VM_READ | VM_EXEC | VM_WRITE;
+#ifdef CONFIG_S390_EXEC_PROTECT
+	if ((regs->psw.mask & PSW_MASK_ASC) == PSW_ASC_SECONDARY &&
+	    (trans_exc_code & 3) == 0)
+		access = VM_EXEC;
+#endif
+	fault = do_exception(regs, access, trans_exc_code);
 	if (unlikely(fault))
 		do_fault_error(regs, int_code & 255, trans_exc_code, fault);
 }
-- 
cgit v1.2.3-70-g09d2


From 6c1e3e79430615d0472dbf9f8fed89c571e66423 Mon Sep 17 00:00:00 2001
From: Gerald Schaefer <gerald.schaefer@de.ibm.com>
Date: Mon, 7 Dec 2009 12:51:47 +0100
Subject: [S390] Use do_exception() in pagetable walk usercopy functions.

The pagetable walk usercopy functions have used a modified copy of the
do_exception() function for fault handling. This lead to inconsistencies
with recent changes to do_exception(), e.g. performance counters. This
patch changes the pagetable walk usercopy code to call do_exception()
directly, eliminating the redundancy. A new parameter is added to
do_exception() to specify the fault address.

Signed-off-by: Gerald Schaefer <gerald.schaefer@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
---
 arch/s390/include/asm/uaccess.h |   2 +
 arch/s390/lib/uaccess_pt.c      | 147 ++++++++++++++--------------------------
 arch/s390/mm/fault.c            |  23 +++++++
 3 files changed, 76 insertions(+), 96 deletions(-)

(limited to 'arch/s390/mm/fault.c')

diff --git a/arch/s390/include/asm/uaccess.h b/arch/s390/include/asm/uaccess.h
index 8377e91533d..cbf0a8745bf 100644
--- a/arch/s390/include/asm/uaccess.h
+++ b/arch/s390/include/asm/uaccess.h
@@ -93,6 +93,8 @@ extern struct uaccess_ops uaccess_mvcos;
 extern struct uaccess_ops uaccess_mvcos_switch;
 extern struct uaccess_ops uaccess_pt;
 
+extern int __handle_fault(unsigned long, unsigned long, int);
+
 static inline int __put_user_fn(size_t size, void __user *ptr, void *x)
 {
 	size = uaccess.copy_to_user_small(size, ptr, x);
diff --git a/arch/s390/lib/uaccess_pt.c b/arch/s390/lib/uaccess_pt.c
index cb5d59eab0e..404f2de296d 100644
--- a/arch/s390/lib/uaccess_pt.c
+++ b/arch/s390/lib/uaccess_pt.c
@@ -23,86 +23,21 @@ static inline pte_t *follow_table(struct mm_struct *mm, unsigned long addr)
 
 	pgd = pgd_offset(mm, addr);
 	if (pgd_none(*pgd) || unlikely(pgd_bad(*pgd)))
-		return NULL;
+		return (pte_t *) 0x3a;
 
 	pud = pud_offset(pgd, addr);
 	if (pud_none(*pud) || unlikely(pud_bad(*pud)))
-		return NULL;
+		return (pte_t *) 0x3b;
 
 	pmd = pmd_offset(pud, addr);
 	if (pmd_none(*pmd) || unlikely(pmd_bad(*pmd)))
-		return NULL;
+		return (pte_t *) 0x10;
 
 	return pte_offset_map(pmd, addr);
 }
 
-static int __handle_fault(struct mm_struct *mm, unsigned long address,
-			  int write_access)
-{
-	struct vm_area_struct *vma;
-	int ret = -EFAULT;
-	int fault;
-
-	if (in_atomic())
-		return ret;
-	down_read(&mm->mmap_sem);
-	vma = find_vma(mm, address);
-	if (unlikely(!vma))
-		goto out;
-	if (unlikely(vma->vm_start > address)) {
-		if (!(vma->vm_flags & VM_GROWSDOWN))
-			goto out;
-		if (expand_stack(vma, address))
-			goto out;
-	}
-
-	if (!write_access) {
-		/* page not present, check vm flags */
-		if (!(vma->vm_flags & (VM_READ | VM_EXEC | VM_WRITE)))
-			goto out;
-	} else {
-		if (!(vma->vm_flags & VM_WRITE))
-			goto out;
-	}
-
-survive:
-	fault = handle_mm_fault(mm, vma, address, write_access ? FAULT_FLAG_WRITE : 0);
-	if (unlikely(fault & VM_FAULT_ERROR)) {
-		if (fault & VM_FAULT_OOM)
-			goto out_of_memory;
-		else if (fault & VM_FAULT_SIGBUS)
-			goto out_sigbus;
-		BUG();
-	}
-	if (fault & VM_FAULT_MAJOR)
-		current->maj_flt++;
-	else
-		current->min_flt++;
-	ret = 0;
-out:
-	up_read(&mm->mmap_sem);
-	return ret;
-
-out_of_memory:
-	up_read(&mm->mmap_sem);
-	if (is_global_init(current)) {
-		yield();
-		down_read(&mm->mmap_sem);
-		goto survive;
-	}
-	printk("VM: killing process %s\n", current->comm);
-	return ret;
-
-out_sigbus:
-	up_read(&mm->mmap_sem);
-	current->thread.prot_addr = address;
-	current->thread.trap_no = 0x11;
-	force_sig(SIGBUS, current);
-	return ret;
-}
-
-static size_t __user_copy_pt(unsigned long uaddr, void *kptr,
-			     size_t n, int write_user)
+static __always_inline size_t __user_copy_pt(unsigned long uaddr, void *kptr,
+					     size_t n, int write_user)
 {
 	struct mm_struct *mm = current->mm;
 	unsigned long offset, pfn, done, size;
@@ -114,12 +49,17 @@ retry:
 	spin_lock(&mm->page_table_lock);
 	do {
 		pte = follow_table(mm, uaddr);
-		if (!pte || !pte_present(*pte) ||
-		    (write_user && !pte_write(*pte)))
+		if ((unsigned long) pte < 0x1000)
 			goto fault;
+		if (!pte_present(*pte)) {
+			pte = (pte_t *) 0x11;
+			goto fault;
+		} else if (write_user && !pte_write(*pte)) {
+			pte = (pte_t *) 0x04;
+			goto fault;
+		}
 
 		pfn = pte_pfn(*pte);
-
 		offset = uaddr & (PAGE_SIZE - 1);
 		size = min(n - done, PAGE_SIZE - offset);
 		if (write_user) {
@@ -137,7 +77,7 @@ retry:
 	return n - done;
 fault:
 	spin_unlock(&mm->page_table_lock);
-	if (__handle_fault(mm, uaddr, write_user))
+	if (__handle_fault(uaddr, (unsigned long) pte, write_user))
 		return n - done;
 	goto retry;
 }
@@ -146,30 +86,31 @@ fault:
  * Do DAT for user address by page table walk, return kernel address.
  * This function needs to be called with current->mm->page_table_lock held.
  */
-static unsigned long __dat_user_addr(unsigned long uaddr)
+static __always_inline unsigned long __dat_user_addr(unsigned long uaddr)
 {
 	struct mm_struct *mm = current->mm;
-	unsigned long pfn, ret;
+	unsigned long pfn;
 	pte_t *pte;
 	int rc;
 
-	ret = 0;
 retry:
 	pte = follow_table(mm, uaddr);
-	if (!pte || !pte_present(*pte))
+	if ((unsigned long) pte < 0x1000)
 		goto fault;
+	if (!pte_present(*pte)) {
+		pte = (pte_t *) 0x11;
+		goto fault;
+	}
 
 	pfn = pte_pfn(*pte);
-	ret = (pfn << PAGE_SHIFT) + (uaddr & (PAGE_SIZE - 1));
-out:
-	return ret;
+	return (pfn << PAGE_SHIFT) + (uaddr & (PAGE_SIZE - 1));
 fault:
 	spin_unlock(&mm->page_table_lock);
-	rc = __handle_fault(mm, uaddr, 0);
+	rc = __handle_fault(uaddr, (unsigned long) pte, 0);
 	spin_lock(&mm->page_table_lock);
-	if (rc)
-		goto out;
-	goto retry;
+	if (!rc)
+		goto retry;
+	return 0;
 }
 
 size_t copy_from_user_pt(size_t n, const void __user *from, void *to)
@@ -234,8 +175,12 @@ retry:
 	spin_lock(&mm->page_table_lock);
 	do {
 		pte = follow_table(mm, uaddr);
-		if (!pte || !pte_present(*pte))
+		if ((unsigned long) pte < 0x1000)
+			goto fault;
+		if (!pte_present(*pte)) {
+			pte = (pte_t *) 0x11;
 			goto fault;
+		}
 
 		pfn = pte_pfn(*pte);
 		offset = uaddr & (PAGE_SIZE-1);
@@ -249,9 +194,8 @@ retry:
 	return done + 1;
 fault:
 	spin_unlock(&mm->page_table_lock);
-	if (__handle_fault(mm, uaddr, 0)) {
+	if (__handle_fault(uaddr, (unsigned long) pte, 0))
 		return 0;
-	}
 	goto retry;
 }
 
@@ -284,7 +228,7 @@ static size_t copy_in_user_pt(size_t n, void __user *to,
 {
 	struct mm_struct *mm = current->mm;
 	unsigned long offset_from, offset_to, offset_max, pfn_from, pfn_to,
-		      uaddr, done, size;
+		      uaddr, done, size, error_code;
 	unsigned long uaddr_from = (unsigned long) from;
 	unsigned long uaddr_to = (unsigned long) to;
 	pte_t *pte_from, *pte_to;
@@ -298,17 +242,28 @@ static size_t copy_in_user_pt(size_t n, void __user *to,
 retry:
 	spin_lock(&mm->page_table_lock);
 	do {
+		write_user = 0;
+		uaddr = uaddr_from;
 		pte_from = follow_table(mm, uaddr_from);
-		if (!pte_from || !pte_present(*pte_from)) {
-			uaddr = uaddr_from;
-			write_user = 0;
+		error_code = (unsigned long) pte_from;
+		if (error_code < 0x1000)
+			goto fault;
+		if (!pte_present(*pte_from)) {
+			error_code = 0x11;
 			goto fault;
 		}
 
+		write_user = 1;
+		uaddr = uaddr_to;
 		pte_to = follow_table(mm, uaddr_to);
-		if (!pte_to || !pte_present(*pte_to) || !pte_write(*pte_to)) {
-			uaddr = uaddr_to;
-			write_user = 1;
+		error_code = (unsigned long) pte_to;
+		if (error_code < 0x1000)
+			goto fault;
+		if (!pte_present(*pte_to)) {
+			error_code = 0x11;
+			goto fault;
+		} else if (!pte_write(*pte_to)) {
+			error_code = 0x04;
 			goto fault;
 		}
 
@@ -329,7 +284,7 @@ retry:
 	return n - done;
 fault:
 	spin_unlock(&mm->page_table_lock);
-	if (__handle_fault(mm, uaddr, write_user))
+	if (__handle_fault(uaddr, error_code, write_user))
 		return n - done;
 	goto retry;
 }
diff --git a/arch/s390/mm/fault.c b/arch/s390/mm/fault.c
index 5a9e9a77dc1..fc102e70d9c 100644
--- a/arch/s390/mm/fault.c
+++ b/arch/s390/mm/fault.c
@@ -442,6 +442,29 @@ no_context:
 }
 #endif
 
+int __handle_fault(unsigned long uaddr, unsigned long int_code, int write_user)
+{
+	struct pt_regs regs;
+	int access, fault;
+
+	regs.psw.mask = psw_kernel_bits;
+	if (!irqs_disabled())
+		regs.psw.mask |= PSW_MASK_IO | PSW_MASK_EXT;
+	regs.psw.addr = (unsigned long) __builtin_return_address(0);
+	regs.psw.addr |= PSW_ADDR_AMODE;
+	uaddr &= PAGE_MASK;
+	access = write_user ? VM_WRITE : VM_READ;
+	fault = do_exception(&regs, access, uaddr | 2);
+	if (unlikely(fault)) {
+		if (fault & VM_FAULT_OOM) {
+			pagefault_out_of_memory();
+			fault = 0;
+		} else if (fault & VM_FAULT_SIGBUS)
+			do_sigbus(&regs, int_code, uaddr);
+	}
+	return fault ? -EFAULT : 0;
+}
+
 #ifdef CONFIG_PFAULT 
 /*
  * 'pfault' pseudo page faults routines.
-- 
cgit v1.2.3-70-g09d2