Merge branch 'x86-smap-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull x86/smap support from Ingo Molnar:
 "This adds support for the SMAP (Supervisor Mode Access Prevention) CPU
  feature on Intel CPUs: a hardware feature that prevents unintended
  user-space data access from kernel privileged code.

  It's turned on automatically when possible.

  This, in combination with SMEP, makes it even harder to exploit kernel
  bugs such as NULL pointer dereferences."

Fix up trivial conflict in arch/x86/kernel/entry_64.S due to newly added
includes right next to each other.

* 'x86-smap-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86, smep, smap: Make the switching functions one-way
  x86, suspend: On wakeup always initialize cr4 and EFER
  x86-32: Start out eflags and cr4 clean
  x86, smap: Do not abuse the [f][x]rstor_checking() functions for user space
  x86-32, smap: Add STAC/CLAC instructions to 32-bit kernel entry
  x86, smap: Reduce the SMAP overhead for signal handling
  x86, smap: A page fault due to SMAP is an oops
  x86, smap: Turn on Supervisor Mode Access Prevention
  x86, smap: Add STAC and CLAC instructions to control user space access
  x86, uaccess: Merge prototypes for clear_user/__clear_user
  x86, smap: Add a header file with macros for STAC/CLAC
  x86, alternative: Add header guards to <asm/alternative-asm.h>
  x86, alternative: Use .pushsection/.popsection
  x86, smap: Add CR4 bit for SMAP
  x86-32, mm: The WP test should be done on a kernel page

1 files changed, 18 insertions, 10 deletions

diff --git a/arch/x86/include/asm/uaccess.h b/arch/x86/include/asm/uaccess.h
index e1f3a17034fc..a91acfbb1a98 100644
--- a/arch/x86/include/asm/uaccess.h
+++ b/arch/x86/include/asm/uaccess.h
@@ -9,6 +9,7 @@
 #include <linux/string.h>
 #include <asm/asm.h>
 #include <asm/page.h>
+#include <asm/smap.h>
 
 #define VERIFY_READ 0
 #define VERIFY_WRITE 1
@@ -192,9 +193,10 @@ extern int __get_user_bad(void);
 
 #ifdef CONFIG_X86_32
 #define __put_user_asm_u64(x, addr, err, errret)			\
-	asm volatile("1:	movl %%eax,0(%2)\n"			\
+	asm volatile(ASM_STAC "\n"					\
+		     "1:	movl %%eax,0(%2)\n"			\
 		     "2:	movl %%edx,4(%2)\n"			\
-		     "3:\n"						\
+		     "3: " ASM_CLAC "\n"				\
 		     ".section .fixup,\"ax\"\n"				\
 		     "4:	movl %3,%0\n"				\
 		     "	jmp 3b\n"					\
@@ -205,9 +207,10 @@ extern int __get_user_bad(void);
 		     : "A" (x), "r" (addr), "i" (errret), "0" (err))
 
 #define __put_user_asm_ex_u64(x, addr)					\
-	asm volatile("1:	movl %%eax,0(%1)\n"			\
+	asm volatile(ASM_STAC "\n"					\
+		     "1:	movl %%eax,0(%1)\n"			\
 		     "2:	movl %%edx,4(%1)\n"			\
-		     "3:\n"						\
+		     "3: " ASM_CLAC "\n"				\
 		     _ASM_EXTABLE_EX(1b, 2b)				\
 		     _ASM_EXTABLE_EX(2b, 3b)				\
 		     : : "A" (x), "r" (addr))
@@ -379,8 +382,9 @@ do {									\
 } while (0)
 
 #define __get_user_asm(x, addr, err, itype, rtype, ltype, errret)	\
-	asm volatile("1:	mov"itype" %2,%"rtype"1\n"		\
-		     "2:\n"						\
+	asm volatile(ASM_STAC "\n"					\
+		     "1:	mov"itype" %2,%"rtype"1\n"		\
+		     "2: " ASM_CLAC "\n"				\
 		     ".section .fixup,\"ax\"\n"				\
 		     "3:	mov %3,%0\n"				\
 		     "	xor"itype" %"rtype"1,%"rtype"1\n"		\
@@ -443,8 +447,9 @@ struct __large_struct { unsigned long buf[100]; };
  * aliasing issues.
  */
 #define __put_user_asm(x, addr, err, itype, rtype, ltype, errret)	\
-	asm volatile("1:	mov"itype" %"rtype"1,%2\n"		\
-		     "2:\n"						\
+	asm volatile(ASM_STAC "\n"					\
+		     "1:	mov"itype" %"rtype"1,%2\n"		\
+		     "2: " ASM_CLAC "\n"				\
 		     ".section .fixup,\"ax\"\n"				\
 		     "3:	mov %3,%0\n"				\
 		     "	jmp 2b\n"					\
@@ -463,13 +468,13 @@ struct __large_struct { unsigned long buf[100]; };
  * uaccess_try and catch
  */
 #define uaccess_try	do {						\
-	int prev_err = current_thread_info()->uaccess_err;		\
 	current_thread_info()->uaccess_err = 0;				\
+	stac();								\
 	barrier();
 
 #define uaccess_catch(err)						\
+	clac();								\
 	(err) |= (current_thread_info()->uaccess_err ? -EFAULT : 0);	\
-	current_thread_info()->uaccess_err = prev_err;			\
 } while (0)
 
 /**
@@ -569,6 +574,9 @@ strncpy_from_user(char *dst, const char __user *src, long count);
 extern __must_check long strlen_user(const char __user *str);
 extern __must_check long strnlen_user(const char __user *str, long n);
 
+unsigned long __must_check clear_user(void __user *mem, unsigned long len);
+unsigned long __must_check __clear_user(void __user *mem, unsigned long len);
+
 /*
  * movsl can be slow when source and dest are not both 8-byte aligned
  */