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

Pull STIBP fallout fixes from Thomas Gleixner:
 "The performance destruction department finally got it's act together
  and came up with a cure for the STIPB regression:

   - Provide a command line option to control the spectre v2 user space
     mitigations. Default is either seccomp or prctl (if seccomp is
     disabled in Kconfig). prctl allows mitigation opt-in, seccomp
     enables the migitation for sandboxed processes.

   - Rework the code to handle the conditional STIBP/IBPB control and
     remove the now unused ptrace_may_access_sched() optimization
     attempt

   - Disable STIBP automatically when SMT is disabled

   - Optimize the switch_to() logic to avoid MSR writes and invocations
     of __switch_to_xtra().

   - Make the asynchronous speculation TIF updates synchronous to
     prevent stale mitigation state.

  As a general cleanup this also makes retpoline directly depend on
  compiler support and removes the 'minimal retpoline' option which just
  pretended to provide some form of security while providing none"

* 'x86-pti-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (31 commits)
  x86/speculation: Provide IBPB always command line options
  x86/speculation: Add seccomp Spectre v2 user space protection mode
  x86/speculation: Enable prctl mode for spectre_v2_user
  x86/speculation: Add prctl() control for indirect branch speculation
  x86/speculation: Prepare arch_smt_update() for PRCTL mode
  x86/speculation: Prevent stale SPEC_CTRL msr content
  x86/speculation: Split out TIF update
  ptrace: Remove unused ptrace_may_access_sched() and MODE_IBRS
  x86/speculation: Prepare for conditional IBPB in switch_mm()
  x86/speculation: Avoid __switch_to_xtra() calls
  x86/process: Consolidate and simplify switch_to_xtra() code
  x86/speculation: Prepare for per task indirect branch speculation control
  x86/speculation: Add command line control for indirect branch speculation
  x86/speculation: Unify conditional spectre v2 print functions
  x86/speculataion: Mark command line parser data __initdata
  x86/speculation: Mark string arrays const correctly
  x86/speculation: Reorder the spec_v2 code
  x86/l1tf: Show actual SMT state
  x86/speculation: Rework SMT state change
  sched/smt: Expose sched_smt_present static key
  ...

1 files changed, 9 insertions, 0 deletions

diff --git a/include/linux/sched.h b/include/linux/sched.h
index d6183a55e8eb..291a9bd5b97f 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -1454,6 +1454,8 @@ static inline bool is_percpu_thread(void)
 #define PFA_SPREAD_SLAB			2	/* Spread some slab caches over cpuset */
 #define PFA_SPEC_SSB_DISABLE		3	/* Speculative Store Bypass disabled */
 #define PFA_SPEC_SSB_FORCE_DISABLE	4	/* Speculative Store Bypass force disabled*/
+#define PFA_SPEC_IB_DISABLE		5	/* Indirect branch speculation restricted */
+#define PFA_SPEC_IB_FORCE_DISABLE	6	/* Indirect branch speculation permanently restricted */
 
 #define TASK_PFA_TEST(name, func)					\
 	static inline bool task_##func(struct task_struct *p)		\
@@ -1485,6 +1487,13 @@ TASK_PFA_CLEAR(SPEC_SSB_DISABLE, spec_ssb_disable)
 TASK_PFA_TEST(SPEC_SSB_FORCE_DISABLE, spec_ssb_force_disable)
 TASK_PFA_SET(SPEC_SSB_FORCE_DISABLE, spec_ssb_force_disable)
 
+TASK_PFA_TEST(SPEC_IB_DISABLE, spec_ib_disable)
+TASK_PFA_SET(SPEC_IB_DISABLE, spec_ib_disable)
+TASK_PFA_CLEAR(SPEC_IB_DISABLE, spec_ib_disable)
+
+TASK_PFA_TEST(SPEC_IB_FORCE_DISABLE, spec_ib_force_disable)
+TASK_PFA_SET(SPEC_IB_FORCE_DISABLE, spec_ib_force_disable)
+
 static inline void
 current_restore_flags(unsigned long orig_flags, unsigned long flags)
 {