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

Pull x86 PTI and Spectre related fixes and updates from Ingo Molnar:
 "Here's the latest set of Spectre and PTI related fixes and updates:

  Spectre:
   - Add entry code register clearing to reduce the Spectre attack
     surface
   - Update the Spectre microcode blacklist
   - Inline the KVM Spectre helpers to get close to v4.14 performance
     again.
   - Fix indirect_branch_prediction_barrier()
   - Fix/improve Spectre related kernel messages
   - Fix array_index_nospec_mask() asm constraint
   - KVM: fix two MSR handling bugs

  PTI:
   - Fix a paranoid entry PTI CR3 handling bug
   - Fix comments

  objtool:
   - Fix paranoid_entry() frame pointer warning
   - Annotate WARN()-related UD2 as reachable
   - Various fixes
   - Add Add Peter Zijlstra as objtool co-maintainer

  Misc:
   - Various x86 entry code self-test fixes
   - Improve/simplify entry code stack frame generation and handling
     after recent heavy-handed PTI and Spectre changes. (There's two
     more WIP improvements expected here.)
   - Type fix for cache entries

  There's also some low risk non-fix changes I've included in this
  branch to reduce backporting conflicts:

   - rename a confusing x86_cpu field name
   - de-obfuscate the naming of single-TLB flushing primitives"

* 'x86-pti-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (41 commits)
  x86/entry/64: Fix CR3 restore in paranoid_exit()
  x86/cpu: Change type of x86_cache_size variable to unsigned int
  x86/spectre: Fix an error message
  x86/cpu: Rename cpu_data.x86_mask to cpu_data.x86_stepping
  selftests/x86/mpx: Fix incorrect bounds with old _sigfault
  x86/mm: Rename flush_tlb_single() and flush_tlb_one() to __flush_tlb_one_[user|kernel]()
  x86/speculation: Add <asm/msr-index.h> dependency
  nospec: Move array_index_nospec() parameter checking into separate macro
  x86/speculation: Fix up array_index_nospec_mask() asm constraint
  x86/debug: Use UD2 for WARN()
  x86/debug, objtool: Annotate WARN()-related UD2 as reachable
  objtool: Fix segfault in ignore_unreachable_insn()
  selftests/x86: Disable tests requiring 32-bit support on pure 64-bit systems
  selftests/x86: Do not rely on "int $0x80" in single_step_syscall.c
  selftests/x86: Do not rely on "int $0x80" in test_mremap_vdso.c
  selftests/x86: Fix build bug caused by the 5lvl test which has been moved to the VM directory
  selftests/x86/pkeys: Remove unused functions
  selftests/x86: Clean up and document sscanf() usage
  selftests/x86: Fix vDSO selftest segfault for vsyscall=none
  x86/entry/64: Remove the unused 'icebp' macro
  ...

1 files changed, 21 insertions, 15 deletions

diff --git a/include/linux/nospec.h b/include/linux/nospec.h
index b99bced39ac2..fbc98e2c8228 100644
--- a/include/linux/nospec.h
+++ b/include/linux/nospec.h
@@ -20,20 +20,6 @@ static inline unsigned long array_index_mask_nospec(unsigned long index,
 						    unsigned long size)
 {
 	/*
-	 * Warn developers about inappropriate array_index_nospec() usage.
-	 *
-	 * Even if the CPU speculates past the WARN_ONCE branch, the
-	 * sign bit of @index is taken into account when generating the
-	 * mask.
-	 *
-	 * This warning is compiled out when the compiler can infer that
-	 * @index and @size are less than LONG_MAX.
-	 */
-	if (WARN_ONCE(index > LONG_MAX || size > LONG_MAX,
-			"array_index_nospec() limited to range of [0, LONG_MAX]\n"))
-		return 0;
-
-	/*
 	 * Always calculate and emit the mask even if the compiler
 	 * thinks the mask is not needed. The compiler does not take
 	 * into account the value of @index under speculation.
@@ -44,6 +30,26 @@ static inline unsigned long array_index_mask_nospec(unsigned long index,
 #endif
 
 /*
+ * Warn developers about inappropriate array_index_nospec() usage.
+ *
+ * Even if the CPU speculates past the WARN_ONCE branch, the
+ * sign bit of @index is taken into account when generating the
+ * mask.
+ *
+ * This warning is compiled out when the compiler can infer that
+ * @index and @size are less than LONG_MAX.
+ */
+#define array_index_mask_nospec_check(index, size)				\
+({										\
+	if (WARN_ONCE(index > LONG_MAX || size > LONG_MAX,			\
+	    "array_index_nospec() limited to range of [0, LONG_MAX]\n"))	\
+		_mask = 0;							\
+	else									\
+		_mask = array_index_mask_nospec(index, size);			\
+	_mask;									\
+})
+
+/*
  * array_index_nospec - sanitize an array index after a bounds check
  *
  * For a code sequence like:
@@ -61,7 +67,7 @@ static inline unsigned long array_index_mask_nospec(unsigned long index,
 ({									\
 	typeof(index) _i = (index);					\
 	typeof(size) _s = (size);					\
-	unsigned long _mask = array_index_mask_nospec(_i, _s);		\
+	unsigned long _mask = array_index_mask_nospec_check(_i, _s);	\
 									\
 	BUILD_BUG_ON(sizeof(_i) > sizeof(long));			\
 	BUILD_BUG_ON(sizeof(_s) > sizeof(long));			\