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

Pull EFI updates from Ingo Molnar:
 "The main changes are:

   - Add support for enlisting the help of the EFI firmware to create
     memory reservations that persist across kexec.

   - Add page fault handling to the runtime services support code on x86
     so we can more gracefully recover from buggy EFI firmware.

   - Fix command line handling on x86 for the boot path that omits the
     stub's PE/COFF entry point.

   - Other assorted fixes and updates"

* 'efi-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86: boot: Fix EFI stub alignment
  efi/x86: Call efi_parse_options() from efi_main()
  efi/x86: earlyprintk - Add 64bit efi fb address support
  efi/x86: drop task_lock() from efi_switch_mm()
  efi/x86: Handle page faults occurring while running EFI runtime services
  efi: Make efi_rts_work accessible to efi page fault handler
  efi/efi_test: add exporting ResetSystem runtime service
  efi/libstub: arm: support building with clang
  efi: add API to reserve memory persistently across kexec reboot
  efi/arm: libstub: add a root memreserve config table
  efi: honour memory reservations passed via a linux specific config table

arch/x86/mm/fault.c

@@ -16,6 +16,7 @@
 #include <linux/prefetch.h>		/* prefetchw			*/
 #include <linux/context_tracking.h>	/* exception_enter(), ...	*/
 #include <linux/uaccess.h>		/* faulthandler_disabled()	*/
+#include <linux/efi.h>			/* efi_recover_from_page_fault()*/
 #include <linux/mm_types.h>
 
 #include <asm/cpufeature.h>		/* boot_cpu_has, ...		*/
@@ -25,6 +26,7 @@
 #include <asm/vsyscall.h>		/* emulate_vsyscall		*/
 #include <asm/vm86.h>			/* struct vm86			*/
 #include <asm/mmu_context.h>		/* vma_pkey()			*/
+#include <asm/efi.h>			/* efi_recover_from_page_fault()*/
 
 #define CREATE_TRACE_POINTS
 #include <asm/trace/exceptions.h>
@@ -788,6 +790,13 @@ no_context(struct pt_regs *regs, unsigned long error_code,
 	if (is_errata93(regs, address))
 		return;
 
+	/*
+	 * Buggy firmware could access regions which might page fault, try to
+	 * recover from such faults.
+	 */
+	if (IS_ENABLED(CONFIG_EFI))
+		efi_recover_from_page_fault(address);
+
 	/*
 	 * Oops. The kernel tried to access some bad page. We'll have to
 	 * terminate things with extreme prejudice: