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

Pull x86 fixes from Thomas Gleixner:
 "Two fixlets for x86:

   - Handle WARN_ONs proper with the new UD based WARN implementation

   - Disable 1G mappings when 2M mappings are disabled by kmemleak or
     debug_pagealloc. Otherwise 1G mappings might still be used,
     confusing the debug mechanisms"

* 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/mm: Disable 1GB direct mappings when disabling 2MB mappings
  x86/debug: Handle early WARN_ONs proper

arch/x86/include/asm/extable.h

@@ -29,6 +29,7 @@ struct pt_regs;
 	} while (0)
 
 extern int fixup_exception(struct pt_regs *regs, int trapnr);
+extern int fixup_bug(struct pt_regs *regs, int trapnr);
 extern bool ex_has_fault_handler(unsigned long ip);
 extern void early_fixup_exception(struct pt_regs *regs, int trapnr);
 

arch/x86/kernel/traps.c

@@ -182,7 +182,7 @@ int is_valid_bugaddr(unsigned long addr)
 	return ud == INSN_UD0 || ud == INSN_UD2;
 }
 
-static int fixup_bug(struct pt_regs *regs, int trapnr)
+int fixup_bug(struct pt_regs *regs, int trapnr)
 {
 	if (trapnr != X86_TRAP_UD)
 		return 0;

arch/x86/mm/extable.c

@@ -162,6 +162,9 @@ void __init early_fixup_exception(struct pt_regs *regs, int trapnr)
 	if (fixup_exception(regs, trapnr))
 		return;
 
+	if (fixup_bug(regs, trapnr))
+		return;
+
 fail:
 	early_printk("PANIC: early exception 0x%02x IP %lx:%lx error %lx cr2 0x%lx\n",
 		     (unsigned)trapnr, (unsigned long)regs->cs, regs->ip,

arch/x86/mm/init.c

@@ -161,16 +161,16 @@ static int page_size_mask;
 
 static void __init probe_page_size_mask(void)
 {
-#if !defined(CONFIG_KMEMCHECK)
 	/*
 	 * For CONFIG_KMEMCHECK or pagealloc debugging, identity mapping will
 	 * use small pages.
 	 * This will simplify cpa(), which otherwise needs to support splitting
 	 * large pages into small in interrupt context, etc.
 	 */
-	if (boot_cpu_has(X86_FEATURE_PSE) && !debug_pagealloc_enabled())
+	if (boot_cpu_has(X86_FEATURE_PSE) && !debug_pagealloc_enabled() && !IS_ENABLED(CONFIG_KMEMCHECK))
 		page_size_mask |= 1 << PG_LEVEL_2M;
-#endif
+	else
+		direct_gbpages = 0;
 
 	/* Enable PSE if available */
 	if (boot_cpu_has(X86_FEATURE_PSE))