Merge branch 'uaccess' (batched user access infrastructure)

Expose an interface to allow users to mark several accesses together as
being user space accesses, allowing batching of the surrounding user
space access markers (SMAP on x86, PAN on arm64, domain register
switching on arm).

This is currently only used for the user string lenth and copying
functions, where the SMAP overhead on x86 drowned the actual user
accesses (only noticeable on newer microarchitectures that support SMAP
in the first place, of course).

* user access batching branch:
  Use the new batched user accesses in generic user string handling
  Add 'unsafe' user access functions for batched accesses
  x86: reorganize SMAP handling in user space accesses

1 files changed, 66 insertions, 28 deletions

diff --git a/arch/x86/include/asm/uaccess_64.h b/arch/x86/include/asm/uaccess_64.h
index f2f9b39b274a..b89c34c4019b 100644
--- a/arch/x86/include/asm/uaccess_64.h
+++ b/arch/x86/include/asm/uaccess_64.h
@@ -56,35 +56,49 @@ int __copy_from_user_nocheck(void *dst, const void __user *src, unsigned size)
 	if (!__builtin_constant_p(size))
 		return copy_user_generic(dst, (__force void *)src, size);
 	switch (size) {
-	case 1:__get_user_asm(*(u8 *)dst, (u8 __user *)src,
+	case 1:
+		__uaccess_begin();
+		__get_user_asm(*(u8 *)dst, (u8 __user *)src,
 			      ret, "b", "b", "=q", 1);
+		__uaccess_end();
 		return ret;
-	case 2:__get_user_asm(*(u16 *)dst, (u16 __user *)src,
+	case 2:
+		__uaccess_begin();
+		__get_user_asm(*(u16 *)dst, (u16 __user *)src,
 			      ret, "w", "w", "=r", 2);
+		__uaccess_end();
 		return ret;
-	case 4:__get_user_asm(*(u32 *)dst, (u32 __user *)src,
+	case 4:
+		__uaccess_begin();
+		__get_user_asm(*(u32 *)dst, (u32 __user *)src,
 			      ret, "l", "k", "=r", 4);
+		__uaccess_end();
 		return ret;
-	case 8:__get_user_asm(*(u64 *)dst, (u64 __user *)src,
+	case 8:
+		__uaccess_begin();
+		__get_user_asm(*(u64 *)dst, (u64 __user *)src,
 			      ret, "q", "", "=r", 8);
+		__uaccess_end();
 		return ret;
 	case 10:
+		__uaccess_begin();
 		__get_user_asm(*(u64 *)dst, (u64 __user *)src,
 			       ret, "q", "", "=r", 10);
-		if (unlikely(ret))
-			return ret;
-		__get_user_asm(*(u16 *)(8 + (char *)dst),
-			       (u16 __user *)(8 + (char __user *)src),
-			       ret, "w", "w", "=r", 2);
+		if (likely(!ret))
+			__get_user_asm(*(u16 *)(8 + (char *)dst),
+				       (u16 __user *)(8 + (char __user *)src),
+				       ret, "w", "w", "=r", 2);
+		__uaccess_end();
 		return ret;
 	case 16:
+		__uaccess_begin();
 		__get_user_asm(*(u64 *)dst, (u64 __user *)src,
 			       ret, "q", "", "=r", 16);
-		if (unlikely(ret))
-			return ret;
-		__get_user_asm(*(u64 *)(8 + (char *)dst),
-			       (u64 __user *)(8 + (char __user *)src),
-			       ret, "q", "", "=r", 8);
+		if (likely(!ret))
+			__get_user_asm(*(u64 *)(8 + (char *)dst),
+				       (u64 __user *)(8 + (char __user *)src),
+				       ret, "q", "", "=r", 8);
+		__uaccess_end();
 		return ret;
 	default:
 		return copy_user_generic(dst, (__force void *)src, size);
@@ -106,35 +120,51 @@ int __copy_to_user_nocheck(void __user *dst, const void *src, unsigned size)
 	if (!__builtin_constant_p(size))
 		return copy_user_generic((__force void *)dst, src, size);
 	switch (size) {
-	case 1:__put_user_asm(*(u8 *)src, (u8 __user *)dst,
+	case 1:
+		__uaccess_begin();
+		__put_user_asm(*(u8 *)src, (u8 __user *)dst,
 			      ret, "b", "b", "iq", 1);
+		__uaccess_end();
 		return ret;
-	case 2:__put_user_asm(*(u16 *)src, (u16 __user *)dst,
+	case 2:
+		__uaccess_begin();
+		__put_user_asm(*(u16 *)src, (u16 __user *)dst,
 			      ret, "w", "w", "ir", 2);
+		__uaccess_end();
 		return ret;
-	case 4:__put_user_asm(*(u32 *)src, (u32 __user *)dst,
+	case 4:
+		__uaccess_begin();
+		__put_user_asm(*(u32 *)src, (u32 __user *)dst,
 			      ret, "l", "k", "ir", 4);
+		__uaccess_end();
 		return ret;
-	case 8:__put_user_asm(*(u64 *)src, (u64 __user *)dst,
+	case 8:
+		__uaccess_begin();
+		__put_user_asm(*(u64 *)src, (u64 __user *)dst,
 			      ret, "q", "", "er", 8);
+		__uaccess_end();
 		return ret;
 	case 10:
+		__uaccess_begin();
 		__put_user_asm(*(u64 *)src, (u64 __user *)dst,
 			       ret, "q", "", "er", 10);
-		if (unlikely(ret))
-			return ret;
-		asm("":::"memory");
-		__put_user_asm(4[(u16 *)src], 4 + (u16 __user *)dst,
-			       ret, "w", "w", "ir", 2);
+		if (likely(!ret)) {
+			asm("":::"memory");
+			__put_user_asm(4[(u16 *)src], 4 + (u16 __user *)dst,
+				       ret, "w", "w", "ir", 2);
+		}
+		__uaccess_end();
 		return ret;
 	case 16:
+		__uaccess_begin();
 		__put_user_asm(*(u64 *)src, (u64 __user *)dst,
 			       ret, "q", "", "er", 16);
-		if (unlikely(ret))
-			return ret;
-		asm("":::"memory");
-		__put_user_asm(1[(u64 *)src], 1 + (u64 __user *)dst,
-			       ret, "q", "", "er", 8);
+		if (likely(!ret)) {
+			asm("":::"memory");
+			__put_user_asm(1[(u64 *)src], 1 + (u64 __user *)dst,
+				       ret, "q", "", "er", 8);
+		}
+		__uaccess_end();
 		return ret;
 	default:
 		return copy_user_generic((__force void *)dst, src, size);
@@ -160,39 +190,47 @@ int __copy_in_user(void __user *dst, const void __user *src, unsigned size)
 	switch (size) {
 	case 1: {
 		u8 tmp;
+		__uaccess_begin();
 		__get_user_asm(tmp, (u8 __user *)src,
 			       ret, "b", "b", "=q", 1);
 		if (likely(!ret))
 			__put_user_asm(tmp, (u8 __user *)dst,
 				       ret, "b", "b", "iq", 1);
+		__uaccess_end();
 		return ret;
 	}
 	case 2: {
 		u16 tmp;
+		__uaccess_begin();
 		__get_user_asm(tmp, (u16 __user *)src,
 			       ret, "w", "w", "=r", 2);
 		if (likely(!ret))
 			__put_user_asm(tmp, (u16 __user *)dst,
 				       ret, "w", "w", "ir", 2);
+		__uaccess_end();
 		return ret;
 	}
 
 	case 4: {
 		u32 tmp;
+		__uaccess_begin();
 		__get_user_asm(tmp, (u32 __user *)src,
 			       ret, "l", "k", "=r", 4);
 		if (likely(!ret))
 			__put_user_asm(tmp, (u32 __user *)dst,
 				       ret, "l", "k", "ir", 4);
+		__uaccess_end();
 		return ret;
 	}
 	case 8: {
 		u64 tmp;
+		__uaccess_begin();
 		__get_user_asm(tmp, (u64 __user *)src,
 			       ret, "q", "", "=r", 8);
 		if (likely(!ret))
 			__put_user_asm(tmp, (u64 __user *)dst,
 				       ret, "q", "", "er", 8);
+		__uaccess_end();
 		return ret;
 	}
 	default: