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

Pull x86 syscall entry code changes for PTI from Ingo Molnar:
 "The main changes here are Andy Lutomirski's changes to switch the
  x86-64 entry code to use the 'per CPU entry trampoline stack'. This,
  besides helping fix KASLR leaks (the pending Page Table Isolation
  (PTI) work), also robustifies the x86 entry code"

* 'WIP.x86-pti.entry-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (26 commits)
  x86/cpufeatures: Make CPU bugs sticky
  x86/paravirt: Provide a way to check for hypervisors
  x86/paravirt: Dont patch flush_tlb_single
  x86/entry/64: Make cpu_entry_area.tss read-only
  x86/entry: Clean up the SYSENTER_stack code
  x86/entry/64: Remove the SYSENTER stack canary
  x86/entry/64: Move the IST stacks into struct cpu_entry_area
  x86/entry/64: Create a per-CPU SYSCALL entry trampoline
  x86/entry/64: Return to userspace from the trampoline stack
  x86/entry/64: Use a per-CPU trampoline stack for IDT entries
  x86/espfix/64: Stop assuming that pt_regs is on the entry stack
  x86/entry/64: Separate cpu_current_top_of_stack from TSS.sp0
  x86/entry: Remap the TSS into the CPU entry area
  x86/entry: Move SYSENTER_stack to the beginning of struct tss_struct
  x86/dumpstack: Handle stack overflow on all stacks
  x86/entry: Fix assumptions that the HW TSS is at the beginning of cpu_tss
  x86/kasan/64: Teach KASAN about the cpu_entry_area
  x86/mm/fixmap: Generalize the GDT fixmap mechanism, introduce struct cpu_entry_area
  x86/entry/gdt: Put per-CPU GDT remaps in ascending order
  x86/dumpstack: Add get_stack_info() support for the SYSENTER stack
  ...

arch/x86/mm/kasan_init_64.c

@@ -277,6 +277,7 @@ void __init kasan_early_init(void)
 void __init kasan_init(void)
 {
 	int i;
+	void *shadow_cpu_entry_begin, *shadow_cpu_entry_end;
 
 #ifdef CONFIG_KASAN_INLINE
 	register_die_notifier(&kasan_die_notifier);
@@ -329,8 +330,23 @@ void __init kasan_init(void)
 			      (unsigned long)kasan_mem_to_shadow(_end),
 			      early_pfn_to_nid(__pa(_stext)));
 
+	shadow_cpu_entry_begin = (void *)__fix_to_virt(FIX_CPU_ENTRY_AREA_BOTTOM);
+	shadow_cpu_entry_begin = kasan_mem_to_shadow(shadow_cpu_entry_begin);
+	shadow_cpu_entry_begin = (void *)round_down((unsigned long)shadow_cpu_entry_begin,
+						PAGE_SIZE);
+
+	shadow_cpu_entry_end = (void *)(__fix_to_virt(FIX_CPU_ENTRY_AREA_TOP) + PAGE_SIZE);
+	shadow_cpu_entry_end = kasan_mem_to_shadow(shadow_cpu_entry_end);
+	shadow_cpu_entry_end = (void *)round_up((unsigned long)shadow_cpu_entry_end,
+					PAGE_SIZE);
+
 	kasan_populate_zero_shadow(kasan_mem_to_shadow((void *)MODULES_END),
-			(void *)KASAN_SHADOW_END);
+				   shadow_cpu_entry_begin);
+
+	kasan_populate_shadow((unsigned long)shadow_cpu_entry_begin,
+			      (unsigned long)shadow_cpu_entry_end, 0);
+
+	kasan_populate_zero_shadow(shadow_cpu_entry_end, (void *)KASAN_SHADOW_END);
 
 	load_cr3(init_top_pgt);
 	__flush_tlb_all();