Merge tag 'x86_mm_for_v5.12' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull x86 mm cleanups from Borislav Petkov:

 - PTRACE_GETREGS/PTRACE_PUTREGS regset selection cleanup

 - Another initial cleanup - more to follow - to the fault handling
   code.

 - Other minor cleanups and corrections.

* tag 'x86_mm_for_v5.12' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (23 commits)
  x86/{fault,efi}: Fix and rename efi_recover_from_page_fault()
  x86/fault: Don't run fixups for SMAP violations
  x86/fault: Don't look for extable entries for SMEP violations
  x86/fault: Rename no_context() to kernelmode_fixup_or_oops()
  x86/fault: Bypass no_context() for implicit kernel faults from usermode
  x86/fault: Split the OOPS code out from no_context()
  x86/fault: Improve kernel-executing-user-memory handling
  x86/fault: Correct a few user vs kernel checks wrt WRUSS
  x86/fault: Document the locking in the fault_signal_pending() path
  x86/fault/32: Move is_f00f_bug() to do_kern_addr_fault()
  x86/fault: Fold mm_fault_error() into do_user_addr_fault()
  x86/fault: Skip the AMD erratum #91 workaround on unaffected CPUs
  x86/fault: Fix AMD erratum #91 errata fixup for user code
  x86/Kconfig: Remove HPET_EMULATE_RTC depends on RTC
  x86/asm: Fixup TASK_SIZE_MAX comment
  x86/ptrace: Clean up PTRACE_GETREGS/PTRACE_PUTREGS regset selection
  x86/vm86/32: Remove VM86_SCREEN_BITMAP support
  x86: Remove definition of DEBUG
  x86/entry: Remove now unused do_IRQ() declaration
  x86/mm: Remove duplicate definition of _PAGE_PAT_LARGE
  ...

1 files changed, 12 insertions, 4 deletions

diff --git a/arch/x86/platform/efi/quirks.c b/arch/x86/platform/efi/quirks.c
index 5a40fe411ebd..67d93a243c35 100644
--- a/arch/x86/platform/efi/quirks.c
+++ b/arch/x86/platform/efi/quirks.c
@@ -687,15 +687,25 @@ int efi_capsule_setup_info(struct capsule_info *cap_info, void *kbuff,
  * @return: Returns, if the page fault is not handled. This function
  * will never return if the page fault is handled successfully.
  */
-void efi_recover_from_page_fault(unsigned long phys_addr)
+void efi_crash_gracefully_on_page_fault(unsigned long phys_addr)
 {
 	if (!IS_ENABLED(CONFIG_X86_64))
 		return;
 
 	/*
+	 * If we get an interrupt/NMI while processing an EFI runtime service
+	 * then this is a regular OOPS, not an EFI failure.
+	 */
+	if (in_interrupt())
+		return;
+
+	/*
 	 * Make sure that an efi runtime service caused the page fault.
+	 * READ_ONCE() because we might be OOPSing in a different thread,
+	 * and we don't want to trip KTSAN while trying to OOPS.
 	 */
-	if (efi_rts_work.efi_rts_id == EFI_NONE)
+	if (READ_ONCE(efi_rts_work.efi_rts_id) == EFI_NONE ||
+	    current_work() != &efi_rts_work.work)
 		return;
 
 	/*
@@ -747,6 +757,4 @@ void efi_recover_from_page_fault(unsigned long phys_addr)
 		set_current_state(TASK_IDLE);
 		schedule();
 	}
-
-	return;
 }