1 files changed, 6 insertions, 58 deletions

diff --git a/arch/x86/mm/tlb.c b/arch/x86/mm/tlb.c
index 658bf0090565..0f3d0cea4d00 100644
--- a/arch/x86/mm/tlb.c
+++ b/arch/x86/mm/tlb.c
@@ -30,7 +30,6 @@
 
 atomic64_t last_mm_ctx_id = ATOMIC64_INIT(1);
 
-DEFINE_STATIC_KEY_TRUE(tlb_use_lazy_mode);
 
 static void choose_new_asid(struct mm_struct *next, u64 next_tlb_gen,
                             u16 *new_asid, bool *need_flush)
@@ -147,8 +146,8 @@ void switch_mm_irqs_off(struct mm_struct *prev, struct mm_struct *next,
         this_cpu_write(cpu_tlbstate.is_lazy, false);
 
         if (real_prev == next) {
-                VM_BUG_ON(this_cpu_read(cpu_tlbstate.ctxs[prev_asid].ctx_id) !=
-                          next->context.ctx_id);
+                VM_WARN_ON(this_cpu_read(cpu_tlbstate.ctxs[prev_asid].ctx_id) !=
+                           next->context.ctx_id);
 
                 /*
                  * We don't currently support having a real mm loaded without
@@ -213,6 +212,9 @@ void switch_mm_irqs_off(struct mm_struct *prev, struct mm_struct *next,
 }
 
 /*
+ * Please ignore the name of this function.  It should be called
+ * switch_to_kernel_thread().
+ *
  * enter_lazy_tlb() is a hint from the scheduler that we are entering a
  * kernel thread or other context without an mm.  Acceptable implementations
  * include doing nothing whatsoever, switching to init_mm, or various clever
@@ -227,7 +229,7 @@ void enter_lazy_tlb(struct mm_struct *mm, struct task_struct *tsk)
         if (this_cpu_read(cpu_tlbstate.loaded_mm) == &init_mm)
                 return;
 
-        if (static_branch_unlikely(&tlb_use_lazy_mode)) {
+        if (tlb_defer_switch_to_init_mm()) {
                 /*
                  * There's a significant optimization that may be possible
                  * here.  We have accurate enough TLB flush tracking that we
@@ -626,57 +628,3 @@ static int __init create_tlb_single_page_flush_ceiling(void)
         return 0;
 }
 late_initcall(create_tlb_single_page_flush_ceiling);
-
-static ssize_t tlblazy_read_file(struct file *file, char __user *user_buf,
-                                 size_t count, loff_t *ppos)
-{
-        char buf[2];
-
-        buf[0] = static_branch_likely(&tlb_use_lazy_mode) ? '1' : '0';
-        buf[1] = '\n';
-
-        return simple_read_from_buffer(user_buf, count, ppos, buf, 2);
-}
-
-static ssize_t tlblazy_write_file(struct file *file,
-                 const char __user *user_buf, size_t count, loff_t *ppos)
-{
-        bool val;
-
-        if (kstrtobool_from_user(user_buf, count, &val))
-                return -EINVAL;
-
-        if (val)
-                static_branch_enable(&tlb_use_lazy_mode);
-        else
-                static_branch_disable(&tlb_use_lazy_mode);
-
-        return count;
-}
-
-static const struct file_operations fops_tlblazy = {
-        .read = tlblazy_read_file,
-        .write = tlblazy_write_file,
-        .llseek = default_llseek,
-};
-
-static int __init init_tlb_use_lazy_mode(void)
-{
-        if (boot_cpu_has(X86_FEATURE_PCID)) {
-                /*
-                 * Heuristic: with PCID on, switching to and from
-                 * init_mm is reasonably fast, but remote flush IPIs
-                 * as expensive as ever, so turn off lazy TLB mode.
-                 *
-                 * We can't do this in setup_pcid() because static keys
-                 * haven't been initialized yet, and it would blow up
-                 * badly.
-                 */
-                static_branch_disable(&tlb_use_lazy_mode);
-        }
-
-        debugfs_create_file("tlb_use_lazy_mode", S_IRUSR | S_IWUSR,
-                            arch_debugfs_dir, NULL, &fops_tlblazy);
-        return 0;
-}
-late_initcall(init_tlb_use_lazy_mode);