Merge tag 'v4.15-rc1' into next-seccomp

Linux 4.15-rc1

1 files changed, 107 insertions, 22 deletions

diff --git a/arch/s390/lib/uaccess.c b/arch/s390/lib/uaccess.c
index b3bd3f23b8e8..cae5a1e16cbd 100644
--- a/arch/s390/lib/uaccess.c
+++ b/arch/s390/lib/uaccess.c
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0
 /*
  *  Standard user space access functions based on mvcp/mvcs and doing
  *  interesting things in the secondary space mode.
@@ -15,12 +16,91 @@
 #include <asm/mmu_context.h>
 #include <asm/facility.h>
 
+#ifndef CONFIG_HAVE_MARCH_Z10_FEATURES
 static DEFINE_STATIC_KEY_FALSE(have_mvcos);
 
+static int __init uaccess_init(void)
+{
+	if (test_facility(27))
+		static_branch_enable(&have_mvcos);
+	return 0;
+}
+early_initcall(uaccess_init);
+
+static inline int copy_with_mvcos(void)
+{
+	if (static_branch_likely(&have_mvcos))
+		return 1;
+	return 0;
+}
+#else
+static inline int copy_with_mvcos(void)
+{
+	return 1;
+}
+#endif
+
+void set_fs(mm_segment_t fs)
+{
+	current->thread.mm_segment = fs;
+	if (fs == USER_DS) {
+		__ctl_load(S390_lowcore.user_asce, 1, 1);
+		clear_cpu_flag(CIF_ASCE_PRIMARY);
+	} else {
+		__ctl_load(S390_lowcore.kernel_asce, 1, 1);
+		set_cpu_flag(CIF_ASCE_PRIMARY);
+	}
+	if (fs & 1) {
+		if (fs == USER_DS_SACF)
+			__ctl_load(S390_lowcore.user_asce, 7, 7);
+		else
+			__ctl_load(S390_lowcore.kernel_asce, 7, 7);
+		set_cpu_flag(CIF_ASCE_SECONDARY);
+	}
+}
+EXPORT_SYMBOL(set_fs);
+
+mm_segment_t enable_sacf_uaccess(void)
+{
+	mm_segment_t old_fs;
+	unsigned long asce, cr;
+
+	old_fs = current->thread.mm_segment;
+	if (old_fs & 1)
+		return old_fs;
+	current->thread.mm_segment |= 1;
+	asce = S390_lowcore.kernel_asce;
+	if (likely(old_fs == USER_DS)) {
+		__ctl_store(cr, 1, 1);
+		if (cr != S390_lowcore.kernel_asce) {
+			__ctl_load(S390_lowcore.kernel_asce, 1, 1);
+			set_cpu_flag(CIF_ASCE_PRIMARY);
+		}
+		asce = S390_lowcore.user_asce;
+	}
+	__ctl_store(cr, 7, 7);
+	if (cr != asce) {
+		__ctl_load(asce, 7, 7);
+		set_cpu_flag(CIF_ASCE_SECONDARY);
+	}
+	return old_fs;
+}
+EXPORT_SYMBOL(enable_sacf_uaccess);
+
+void disable_sacf_uaccess(mm_segment_t old_fs)
+{
+	if (old_fs == USER_DS && test_facility(27)) {
+		__ctl_load(S390_lowcore.user_asce, 1, 1);
+		clear_cpu_flag(CIF_ASCE_PRIMARY);
+	}
+	current->thread.mm_segment = old_fs;
+}
+EXPORT_SYMBOL(disable_sacf_uaccess);
+
 static inline unsigned long copy_from_user_mvcos(void *x, const void __user *ptr,
 						 unsigned long size)
 {
-	register unsigned long reg0 asm("0") = 0x81UL;
+	register unsigned long reg0 asm("0") = 0x01UL;
 	unsigned long tmp1, tmp2;
 
 	tmp1 = -4096UL;
@@ -51,8 +131,9 @@ static inline unsigned long copy_from_user_mvcp(void *x, const void __user *ptr,
 						unsigned long size)
 {
 	unsigned long tmp1, tmp2;
+	mm_segment_t old_fs;
 
-	load_kernel_asce();
+	old_fs = enable_sacf_uaccess();
 	tmp1 = -256UL;
 	asm volatile(
 		"   sacf  0\n"
@@ -79,12 +160,13 @@ static inline unsigned long copy_from_user_mvcp(void *x, const void __user *ptr,
 		EX_TABLE(7b,3b) EX_TABLE(8b,3b) EX_TABLE(9b,6b)
 		: "+a" (size), "+a" (ptr), "+a" (x), "+a" (tmp1), "=a" (tmp2)
 		: : "cc", "memory");
+	disable_sacf_uaccess(old_fs);
 	return size;
 }
 
 unsigned long raw_copy_from_user(void *to, const void __user *from, unsigned long n)
 {
-	if (static_branch_likely(&have_mvcos))
+	if (copy_with_mvcos())
 		return copy_from_user_mvcos(to, from, n);
 	return copy_from_user_mvcp(to, from, n);
 }
@@ -93,7 +175,7 @@ EXPORT_SYMBOL(raw_copy_from_user);
 static inline unsigned long copy_to_user_mvcos(void __user *ptr, const void *x,
 					       unsigned long size)
 {
-	register unsigned long reg0 asm("0") = 0x810000UL;
+	register unsigned long reg0 asm("0") = 0x010000UL;
 	unsigned long tmp1, tmp2;
 
 	tmp1 = -4096UL;
@@ -124,8 +206,9 @@ static inline unsigned long copy_to_user_mvcs(void __user *ptr, const void *x,
 					      unsigned long size)
 {
 	unsigned long tmp1, tmp2;
+	mm_segment_t old_fs;
 
-	load_kernel_asce();
+	old_fs = enable_sacf_uaccess();
 	tmp1 = -256UL;
 	asm volatile(
 		"   sacf  0\n"
@@ -152,12 +235,13 @@ static inline unsigned long copy_to_user_mvcs(void __user *ptr, const void *x,
 		EX_TABLE(7b,3b) EX_TABLE(8b,3b) EX_TABLE(9b,6b)
 		: "+a" (size), "+a" (ptr), "+a" (x), "+a" (tmp1), "=a" (tmp2)
 		: : "cc", "memory");
+	disable_sacf_uaccess(old_fs);
 	return size;
 }
 
 unsigned long raw_copy_to_user(void __user *to, const void *from, unsigned long n)
 {
-	if (static_branch_likely(&have_mvcos))
+	if (copy_with_mvcos())
 		return copy_to_user_mvcos(to, from, n);
 	return copy_to_user_mvcs(to, from, n);
 }
@@ -166,7 +250,7 @@ EXPORT_SYMBOL(raw_copy_to_user);
 static inline unsigned long copy_in_user_mvcos(void __user *to, const void __user *from,
 					       unsigned long size)
 {
-	register unsigned long reg0 asm("0") = 0x810081UL;
+	register unsigned long reg0 asm("0") = 0x010001UL;
 	unsigned long tmp1, tmp2;
 
 	tmp1 = -4096UL;
@@ -189,9 +273,10 @@ static inline unsigned long copy_in_user_mvcos(void __user *to, const void __use
 static inline unsigned long copy_in_user_mvc(void __user *to, const void __user *from,
 					     unsigned long size)
 {
+	mm_segment_t old_fs;
 	unsigned long tmp1;
 
-	load_kernel_asce();
+	old_fs = enable_sacf_uaccess();
 	asm volatile(
 		"   sacf  256\n"
 		"   aghi  %0,-1\n"
@@ -215,12 +300,13 @@ static inline unsigned long copy_in_user_mvc(void __user *to, const void __user
 		EX_TABLE(1b,6b) EX_TABLE(2b,0b) EX_TABLE(4b,0b)
 		: "+a" (size), "+a" (to), "+a" (from), "=a" (tmp1)
 		: : "cc", "memory");
+	disable_sacf_uaccess(old_fs);
 	return size;
 }
 
 unsigned long raw_copy_in_user(void __user *to, const void __user *from, unsigned long n)
 {
-	if (static_branch_likely(&have_mvcos))
+	if (copy_with_mvcos())
 		return copy_in_user_mvcos(to, from, n);
 	return copy_in_user_mvc(to, from, n);
 }
@@ -228,7 +314,7 @@ EXPORT_SYMBOL(raw_copy_in_user);
 
 static inline unsigned long clear_user_mvcos(void __user *to, unsigned long size)
 {
-	register unsigned long reg0 asm("0") = 0x810000UL;
+	register unsigned long reg0 asm("0") = 0x010000UL;
 	unsigned long tmp1, tmp2;
 
 	tmp1 = -4096UL;
@@ -256,9 +342,10 @@ static inline unsigned long clear_user_mvcos(void __user *to, unsigned long size
 
 static inline unsigned long clear_user_xc(void __user *to, unsigned long size)
 {
+	mm_segment_t old_fs;
 	unsigned long tmp1, tmp2;
 
-	load_kernel_asce();
+	old_fs = enable_sacf_uaccess();
 	asm volatile(
 		"   sacf  256\n"
 		"   aghi  %0,-1\n"
@@ -287,12 +374,13 @@ static inline unsigned long clear_user_xc(void __user *to, unsigned long size)
 		EX_TABLE(1b,6b) EX_TABLE(2b,0b) EX_TABLE(4b,0b)
 		: "+a" (size), "+a" (to), "=a" (tmp1), "=a" (tmp2)
 		: : "cc", "memory");
+	disable_sacf_uaccess(old_fs);
 	return size;
 }
 
 unsigned long __clear_user(void __user *to, unsigned long size)
 {
-	if (static_branch_likely(&have_mvcos))
+	if (copy_with_mvcos())
 			return clear_user_mvcos(to, size);
 	return clear_user_xc(to, size);
 }
@@ -322,10 +410,15 @@ static inline unsigned long strnlen_user_srst(const char __user *src,
 
 unsigned long __strnlen_user(const char __user *src, unsigned long size)
 {
+	mm_segment_t old_fs;
+	unsigned long len;
+
 	if (unlikely(!size))
 		return 0;
-	load_kernel_asce();
-	return strnlen_user_srst(src, size);
+	old_fs = enable_sacf_uaccess();
+	len = strnlen_user_srst(src, size);
+	disable_sacf_uaccess(old_fs);
+	return len;
 }
 EXPORT_SYMBOL(__strnlen_user);
 
@@ -349,11 +442,3 @@ long __strncpy_from_user(char *dst, const char __user *src, long size)
 	return done;
 }
 EXPORT_SYMBOL(__strncpy_from_user);
-
-static int __init uaccess_init(void)
-{
-	if (test_facility(27))
-		static_branch_enable(&have_mvcos);
-	return 0;
-}
-early_initcall(uaccess_init);