Merge tag 'x86_mm_for_v5.17_rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull x86 mm updates from Borislav Petkov:

 - Flush *all* mappings from the TLB after switching to the trampoline
   pagetable to prevent any stale entries' presence

 - Flush global mappings from the TLB, in addition to the CR3-write,
   after switching off of the trampoline_pgd during boot to clear the
   identity mappings

 - Prevent instrumentation issues resulting from the above changes

* tag 'x86_mm_for_v5.17_rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/mm: Prevent early boot triple-faults with instrumentation
  x86/mm: Include spinlock_t definition in pgtable.
  x86/mm: Flush global TLB when switching to trampoline page-table
  x86/mm/64: Flush global TLB on boot and AP bringup
  x86/realmode: Add comment for Global bit usage in trampoline_pgd
  x86/mm: Add missing <asm/cpufeatures.h> dependency to <asm/page_64.h>

1 files changed, 14 insertions, 0 deletions

diff --git a/arch/x86/kernel/head64.c b/arch/x86/kernel/head64.c
index 3be9dd213dad..de563db9cdcd 100644
--- a/arch/x86/kernel/head64.c
+++ b/arch/x86/kernel/head64.c
@@ -487,6 +487,10 @@ asmlinkage __visible void __init x86_64_start_kernel(char * real_mode_data)
 
 	clear_bss();
 
+	/*
+	 * This needs to happen *before* kasan_early_init() because latter maps stuff
+	 * into that page.
+	 */
 	clear_page(init_top_pgt);
 
 	/*
@@ -498,6 +502,16 @@ asmlinkage __visible void __init x86_64_start_kernel(char * real_mode_data)
 
 	kasan_early_init();
 
+	/*
+	 * Flush global TLB entries which could be left over from the trampoline page
+	 * table.
+	 *
+	 * This needs to happen *after* kasan_early_init() as KASAN-enabled .configs
+	 * instrument native_write_cr4() so KASAN must be initialized for that
+	 * instrumentation to work.
+	 */
+	__native_tlb_flush_global(this_cpu_read(cpu_tlbstate.cr4));
+
 	idt_setup_early_handler();
 
 	copy_bootdata(__va(real_mode_data));