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

6 files changed, 42 insertions, 2 deletions

diff --git a/arch/x86/lib/copy_user_64.S b/arch/x86/lib/copy_user_64.S
index 5b2995f..a30ca15 100644
--- a/arch/x86/lib/copy_user_64.S
+++ b/arch/x86/lib/copy_user_64.S
@@ -17,6 +17,7 @@
 #include <asm/cpufeature.h>
 #include <asm/alternative-asm.h>
 #include <asm/asm.h>
+#include <asm/smap.h>
 
 /*
  * By placing feature2 after feature1 in altinstructions section, we logically
@@ -130,6 +131,7 @@ ENDPROC(bad_from_user)
  */
 ENTRY(copy_user_generic_unrolled)
 	CFI_STARTPROC
+	ASM_STAC
 	cmpl $8,%edx
 	jb 20f		/* less then 8 bytes, go to byte copy loop */
 	ALIGN_DESTINATION
@@ -177,6 +179,7 @@ ENTRY(copy_user_generic_unrolled)
 	decl %ecx
 	jnz 21b
 23:	xor %eax,%eax
+	ASM_CLAC
 	ret
 
 	.section .fixup,"ax"
@@ -232,6 +235,7 @@ ENDPROC(copy_user_generic_unrolled)
  */
 ENTRY(copy_user_generic_string)
 	CFI_STARTPROC
+	ASM_STAC
 	andl %edx,%edx
 	jz 4f
 	cmpl $8,%edx
@@ -246,6 +250,7 @@ ENTRY(copy_user_generic_string)
 3:	rep
 	movsb
 4:	xorl %eax,%eax
+	ASM_CLAC
 	ret
 
 	.section .fixup,"ax"
@@ -273,12 +278,14 @@ ENDPROC(copy_user_generic_string)
  */
 ENTRY(copy_user_enhanced_fast_string)
 	CFI_STARTPROC
+	ASM_STAC
 	andl %edx,%edx
 	jz 2f
 	movl %edx,%ecx
 1:	rep
 	movsb
 2:	xorl %eax,%eax
+	ASM_CLAC
 	ret
 
 	.section .fixup,"ax"
diff --git a/arch/x86/lib/copy_user_nocache_64.S b/arch/x86/lib/copy_user_nocache_64.S
index cacddc7..6a4f43c 100644
--- a/arch/x86/lib/copy_user_nocache_64.S
+++ b/arch/x86/lib/copy_user_nocache_64.S
@@ -15,6 +15,7 @@
 #include <asm/asm-offsets.h>
 #include <asm/thread_info.h>
 #include <asm/asm.h>
+#include <asm/smap.h>
 
 	.macro ALIGN_DESTINATION
 #ifdef FIX_ALIGNMENT
@@ -48,6 +49,7 @@
  */
 ENTRY(__copy_user_nocache)
 	CFI_STARTPROC
+	ASM_STAC
 	cmpl $8,%edx
 	jb 20f		/* less then 8 bytes, go to byte copy loop */
 	ALIGN_DESTINATION
@@ -95,6 +97,7 @@ ENTRY(__copy_user_nocache)
 	decl %ecx
 	jnz 21b
 23:	xorl %eax,%eax
+	ASM_CLAC
 	sfence
 	ret
 
diff --git a/arch/x86/lib/getuser.S b/arch/x86/lib/getuser.S
index b33b1fb..156b9c8 100644
--- a/arch/x86/lib/getuser.S
+++ b/arch/x86/lib/getuser.S
@@ -33,6 +33,7 @@
 #include <asm/asm-offsets.h>
 #include <asm/thread_info.h>
 #include <asm/asm.h>
+#include <asm/smap.h>
 
 	.text
 ENTRY(__get_user_1)
@@ -40,8 +41,10 @@ ENTRY(__get_user_1)
 	GET_THREAD_INFO(%_ASM_DX)
 	cmp TI_addr_limit(%_ASM_DX),%_ASM_AX
 	jae bad_get_user
+	ASM_STAC
 1:	movzb (%_ASM_AX),%edx
 	xor %eax,%eax
+	ASM_CLAC
 	ret
 	CFI_ENDPROC
 ENDPROC(__get_user_1)
@@ -53,8 +56,10 @@ ENTRY(__get_user_2)
 	GET_THREAD_INFO(%_ASM_DX)
 	cmp TI_addr_limit(%_ASM_DX),%_ASM_AX
 	jae bad_get_user
+	ASM_STAC
 2:	movzwl -1(%_ASM_AX),%edx
 	xor %eax,%eax
+	ASM_CLAC
 	ret
 	CFI_ENDPROC
 ENDPROC(__get_user_2)
@@ -66,8 +71,10 @@ ENTRY(__get_user_4)
 	GET_THREAD_INFO(%_ASM_DX)
 	cmp TI_addr_limit(%_ASM_DX),%_ASM_AX
 	jae bad_get_user
+	ASM_STAC
 3:	mov -3(%_ASM_AX),%edx
 	xor %eax,%eax
+	ASM_CLAC
 	ret
 	CFI_ENDPROC
 ENDPROC(__get_user_4)
@@ -80,8 +87,10 @@ ENTRY(__get_user_8)
 	GET_THREAD_INFO(%_ASM_DX)
 	cmp TI_addr_limit(%_ASM_DX),%_ASM_AX
 	jae	bad_get_user
+	ASM_STAC
 4:	movq -7(%_ASM_AX),%_ASM_DX
 	xor %eax,%eax
+	ASM_CLAC
 	ret
 	CFI_ENDPROC
 ENDPROC(__get_user_8)
@@ -91,6 +100,7 @@ bad_get_user:
 	CFI_STARTPROC
 	xor %edx,%edx
 	mov $(-EFAULT),%_ASM_AX
+	ASM_CLAC
 	ret
 	CFI_ENDPROC
 END(bad_get_user)
diff --git a/arch/x86/lib/putuser.S b/arch/x86/lib/putuser.S
index 7f951c8..fc6ba17 100644
--- a/arch/x86/lib/putuser.S
+++ b/arch/x86/lib/putuser.S
@@ -15,6 +15,7 @@
 #include <asm/thread_info.h>
 #include <asm/errno.h>
 #include <asm/asm.h>
+#include <asm/smap.h>
 
 
 /*
@@ -31,7 +32,8 @@
 
 #define ENTER	CFI_STARTPROC ; \
 		GET_THREAD_INFO(%_ASM_BX)
-#define EXIT	ret ; \
+#define EXIT	ASM_CLAC ;	\
+		ret ;		\
 		CFI_ENDPROC
 
 .text
@@ -39,6 +41,7 @@ ENTRY(__put_user_1)
 	ENTER
 	cmp TI_addr_limit(%_ASM_BX),%_ASM_CX
 	jae bad_put_user
+	ASM_STAC
 1:	movb %al,(%_ASM_CX)
 	xor %eax,%eax
 	EXIT
@@ -50,6 +53,7 @@ ENTRY(__put_user_2)
 	sub $1,%_ASM_BX
 	cmp %_ASM_BX,%_ASM_CX
 	jae bad_put_user
+	ASM_STAC
 2:	movw %ax,(%_ASM_CX)
 	xor %eax,%eax
 	EXIT
@@ -61,6 +65,7 @@ ENTRY(__put_user_4)
 	sub $3,%_ASM_BX
 	cmp %_ASM_BX,%_ASM_CX
 	jae bad_put_user
+	ASM_STAC
 3:	movl %eax,(%_ASM_CX)
 	xor %eax,%eax
 	EXIT
@@ -72,6 +77,7 @@ ENTRY(__put_user_8)
 	sub $7,%_ASM_BX
 	cmp %_ASM_BX,%_ASM_CX
 	jae bad_put_user
+	ASM_STAC
 4:	mov %_ASM_AX,(%_ASM_CX)
 #ifdef CONFIG_X86_32
 5:	movl %edx,4(%_ASM_CX)
diff --git a/arch/x86/lib/usercopy_32.c b/arch/x86/lib/usercopy_32.c
index 1781b2f..98f6d6b6 100644
--- a/arch/x86/lib/usercopy_32.c
+++ b/arch/x86/lib/usercopy_32.c
@@ -42,10 +42,11 @@ do {									\
 	int __d0;							\
 	might_fault();							\
 	__asm__ __volatile__(						\
+		ASM_STAC "\n"						\
 		"0:	rep; stosl\n"					\
 		"	movl %2,%0\n"					\
 		"1:	rep; stosb\n"					\
-		"2:\n"							\
+		"2: " ASM_CLAC "\n"					\
 		".section .fixup,\"ax\"\n"				\
 		"3:	lea 0(%2,%0,4),%0\n"				\
 		"	jmp 2b\n"					\
@@ -626,10 +627,12 @@ survive:
 		return n;
 	}
 #endif
+	stac();
 	if (movsl_is_ok(to, from, n))
 		__copy_user(to, from, n);
 	else
 		n = __copy_user_intel(to, from, n);
+	clac();
 	return n;
 }
 EXPORT_SYMBOL(__copy_to_user_ll);
@@ -637,10 +640,12 @@ EXPORT_SYMBOL(__copy_to_user_ll);
 unsigned long __copy_from_user_ll(void *to, const void __user *from,
 					unsigned long n)
 {
+	stac();
 	if (movsl_is_ok(to, from, n))
 		__copy_user_zeroing(to, from, n);
 	else
 		n = __copy_user_zeroing_intel(to, from, n);
+	clac();
 	return n;
 }
 EXPORT_SYMBOL(__copy_from_user_ll);
@@ -648,11 +653,13 @@ EXPORT_SYMBOL(__copy_from_user_ll);
 unsigned long __copy_from_user_ll_nozero(void *to, const void __user *from,
 					 unsigned long n)
 {
+	stac();
 	if (movsl_is_ok(to, from, n))
 		__copy_user(to, from, n);
 	else
 		n = __copy_user_intel((void __user *)to,
 				      (const void *)from, n);
+	clac();
 	return n;
 }
 EXPORT_SYMBOL(__copy_from_user_ll_nozero);
@@ -660,6 +667,7 @@ EXPORT_SYMBOL(__copy_from_user_ll_nozero);
 unsigned long __copy_from_user_ll_nocache(void *to, const void __user *from,
 					unsigned long n)
 {
+	stac();
 #ifdef CONFIG_X86_INTEL_USERCOPY
 	if (n > 64 && cpu_has_xmm2)
 		n = __copy_user_zeroing_intel_nocache(to, from, n);
@@ -668,6 +676,7 @@ unsigned long __copy_from_user_ll_nocache(void *to, const void __user *from,
 #else
 	__copy_user_zeroing(to, from, n);
 #endif
+	clac();
 	return n;
 }
 EXPORT_SYMBOL(__copy_from_user_ll_nocache);
@@ -675,6 +684,7 @@ EXPORT_SYMBOL(__copy_from_user_ll_nocache);
 unsigned long __copy_from_user_ll_nocache_nozero(void *to, const void __user *from,
 					unsigned long n)
 {
+	stac();
 #ifdef CONFIG_X86_INTEL_USERCOPY
 	if (n > 64 && cpu_has_xmm2)
 		n = __copy_user_intel_nocache(to, from, n);
@@ -683,6 +693,7 @@ unsigned long __copy_from_user_ll_nocache_nozero(void *to, const void __user *fr
 #else
 	__copy_user(to, from, n);
 #endif
+	clac();
 	return n;
 }
 EXPORT_SYMBOL(__copy_from_user_ll_nocache_nozero);
diff --git a/arch/x86/lib/usercopy_64.c b/arch/x86/lib/usercopy_64.c
index e5b130b..05928aa 100644
--- a/arch/x86/lib/usercopy_64.c
+++ b/arch/x86/lib/usercopy_64.c
@@ -18,6 +18,7 @@ unsigned long __clear_user(void __user *addr, unsigned long size)
 	might_fault();
 	/* no memory constraint because it doesn't change any memory gcc knows
 	   about */
+	stac();
 	asm volatile(
 		"	testq  %[size8],%[size8]\n"
 		"	jz     4f\n"
@@ -40,6 +41,7 @@ unsigned long __clear_user(void __user *addr, unsigned long size)
 		: [size8] "=&c"(size), [dst] "=&D" (__d0)
 		: [size1] "r"(size & 7), "[size8]" (size / 8), "[dst]"(addr),
 		  [zero] "r" (0UL), [eight] "r" (8UL));
+	clac();
 	return size;
 }
 EXPORT_SYMBOL(__clear_user);
@@ -82,5 +84,6 @@ copy_user_handle_tail(char *to, char *from, unsigned len, unsigned zerorest)
 	for (c = 0, zero_len = len; zerorest && zero_len; --zero_len)
 		if (__put_user_nocheck(c, to++, sizeof(char)))
 			break;
+	clac();
 	return len;
 }