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

Pull x86 fixes from Peter Anvin:
 "A collection of small fixes:

   - There still seem to be problems with asm goto which requires the
     empty asm hack.
   - If SMAP is disabled at compile time, don't enable it nor try to
     interpret a page fault as an SMAP violation.
   - Fix a case of unbounded recursion while tracing"

* 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86, smap: smap_violation() is bogus if CONFIG_X86_SMAP is off
  x86, smap: Don't enable SMAP if CONFIG_X86_SMAP is disabled
  compiler/gcc4: Make quirk for asm_volatile_goto() unconditional
  x86: Use preempt_disable_notrace() in cycles_2_ns()

3 files changed, 17 insertions, 8 deletions

diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c
index 24b6fd10625a..8e28bf2fc3ef 100644
--- a/arch/x86/kernel/cpu/common.c
+++ b/arch/x86/kernel/cpu/common.c
@@ -284,8 +284,13 @@ static __always_inline void setup_smap(struct cpuinfo_x86 *c)
         raw_local_save_flags(eflags);
         BUG_ON(eflags & X86_EFLAGS_AC);
 
-        if (cpu_has(c, X86_FEATURE_SMAP))
+        if (cpu_has(c, X86_FEATURE_SMAP)) {
+#ifdef CONFIG_X86_SMAP
                 set_in_cr4(X86_CR4_SMAP);
+#else
+                clear_in_cr4(X86_CR4_SMAP);
+#endif
+        }
 }
 
 /*
diff --git a/arch/x86/kernel/tsc.c b/arch/x86/kernel/tsc.c
index 19e5adb49a27..acb3b606613e 100644
--- a/arch/x86/kernel/tsc.c
+++ b/arch/x86/kernel/tsc.c
@@ -209,7 +209,7 @@ static inline unsigned long long cycles_2_ns(unsigned long long cyc)
          * dance when its actually needed.
          */
 
-        preempt_disable();
+        preempt_disable_notrace();
         data = this_cpu_read(cyc2ns.head);
         tail = this_cpu_read(cyc2ns.tail);
 
@@ -229,7 +229,7 @@ static inline unsigned long long cycles_2_ns(unsigned long long cyc)
                 if (!--data->__count)
                         this_cpu_write(cyc2ns.tail, data);
         }
-        preempt_enable();
+        preempt_enable_notrace();
 
         return ns;
 }
diff --git a/arch/x86/mm/fault.c b/arch/x86/mm/fault.c
index 9d591c895803..6dea040cc3a1 100644
--- a/arch/x86/mm/fault.c
+++ b/arch/x86/mm/fault.c
@@ -1001,6 +1001,12 @@ static int fault_in_kernel_space(unsigned long address)
 
 static inline bool smap_violation(int error_code, struct pt_regs *regs)
 {
+        if (!IS_ENABLED(CONFIG_X86_SMAP))
+                return false;
+
+        if (!static_cpu_has(X86_FEATURE_SMAP))
+                return false;
+
         if (error_code & PF_USER)
                 return false;
 
@@ -1087,11 +1093,9 @@ __do_page_fault(struct pt_regs *regs, unsigned long error_code)
         if (unlikely(error_code & PF_RSVD))
                 pgtable_bad(regs, error_code, address);
 
-        if (static_cpu_has(X86_FEATURE_SMAP)) {
-                if (unlikely(smap_violation(error_code, regs))) {
-                        bad_area_nosemaphore(regs, error_code, address);
-                        return;
-                }
+        if (unlikely(smap_violation(error_code, regs))) {
+                bad_area_nosemaphore(regs, error_code, address);
+                return;
         }
 
         /*