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, 10 insertions, 1 deletions

diff --git a/arch/x86/kernel/entry_64.S b/arch/x86/kernel/entry_64.S
index 066334be7b74..44531acd9a81 100644
--- a/arch/x86/kernel/entry_64.S
+++ b/arch/x86/kernel/entry_64.S
@@ -57,6 +57,7 @@
 #include <asm/percpu.h>
 #include <asm/asm.h>
 #include <asm/rcu.h>
+#include <asm/smap.h>
 #include <linux/err.h>
 
 /* Avoid __ASSEMBLER__'ifying <linux/audit.h> just for this.  */
@@ -568,7 +569,8 @@ END(ret_from_fork)
  * System call entry. Up to 6 arguments in registers are supported.
  *
  * SYSCALL does not save anything on the stack and does not change the
- * stack pointer.
+ * stack pointer.  However, it does mask the flags register for us, so
+ * CLD and CLAC are not needed.
  */
 
 /*
@@ -987,6 +989,7 @@ END(interrupt)
          */
         .p2align CONFIG_X86_L1_CACHE_SHIFT
 common_interrupt:
+        ASM_CLAC
         XCPT_FRAME
         addq $-0x80,(%rsp)              /* Adjust vector to [-256,-1] range */
         interrupt do_IRQ
@@ -1126,6 +1129,7 @@ END(common_interrupt)
  */
 .macro apicinterrupt num sym do_sym
 ENTRY(\sym)
+        ASM_CLAC
         INTR_FRAME
         pushq_cfi $~(\num)
 .Lcommon_\sym:
@@ -1180,6 +1184,7 @@ apicinterrupt IRQ_WORK_VECTOR \
  */
 .macro zeroentry sym do_sym
 ENTRY(\sym)
+        ASM_CLAC
         INTR_FRAME
         PARAVIRT_ADJUST_EXCEPTION_FRAME
         pushq_cfi $-1           /* ORIG_RAX: no syscall to restart */
@@ -1197,6 +1202,7 @@ END(\sym)
 
 .macro paranoidzeroentry sym do_sym
 ENTRY(\sym)
+        ASM_CLAC
         INTR_FRAME
         PARAVIRT_ADJUST_EXCEPTION_FRAME
         pushq_cfi $-1           /* ORIG_RAX: no syscall to restart */
@@ -1215,6 +1221,7 @@ END(\sym)
 #define INIT_TSS_IST(x) PER_CPU_VAR(init_tss) + (TSS_ist + ((x) - 1) * 8)
 .macro paranoidzeroentry_ist sym do_sym ist
 ENTRY(\sym)
+        ASM_CLAC
         INTR_FRAME
         PARAVIRT_ADJUST_EXCEPTION_FRAME
         pushq_cfi $-1           /* ORIG_RAX: no syscall to restart */
@@ -1234,6 +1241,7 @@ END(\sym)
 
 .macro errorentry sym do_sym
 ENTRY(\sym)
+        ASM_CLAC
         XCPT_FRAME
         PARAVIRT_ADJUST_EXCEPTION_FRAME
         subq $ORIG_RAX-R15, %rsp
@@ -1252,6 +1260,7 @@ END(\sym)
         /* error code is on the stack already */
 .macro paranoiderrorentry sym do_sym
 ENTRY(\sym)
+        ASM_CLAC
         XCPT_FRAME
         PARAVIRT_ADJUST_EXCEPTION_FRAME
         subq $ORIG_RAX-R15, %rsp