Two fixes:

- Fix build failure on Ubuntu with new GCC packages that turn on -fcf-protection
 
  - Fix SME memory encryption PTE encoding bug - AFAICT the code worked on
    4K page sizes (level 1) but had the wrong shift at higher page level orders
    (level 2 and higher).
 
 Signed-off-by: Ingo Molnar <mingo@kernel.org>
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Merge tag 'x86-urgent-2021-03-28' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull x86 fixes from Ingo Molnar:
 "Two fixes:

   - Fix build failure on Ubuntu with new GCC packages that turn
     on -fcf-protection

   - Fix SME memory encryption PTE encoding bug - AFAICT the code
     worked on 4K page sizes (level 1) but had the wrong shift at
     higher page level orders (level 2 and higher)"

* tag 'x86-urgent-2021-03-28' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/build: Turn off -fcf-protection for realmode targets
  x86/mem_encrypt: Correct physical address calculation in __set_clr_pte_enc()

arch/x86/Makefile

@@ -27,7 +27,7 @@ endif
 REALMODE_CFLAGS	:= -m16 -g -Os -DDISABLE_BRANCH_PROFILING \
 		   -Wall -Wstrict-prototypes -march=i386 -mregparm=3 \
 		   -fno-strict-aliasing -fomit-frame-pointer -fno-pic \
-		   -mno-mmx -mno-sse
+		   -mno-mmx -mno-sse $(call cc-option,-fcf-protection=none)
 
 REALMODE_CFLAGS += -ffreestanding
 REALMODE_CFLAGS += -fno-stack-protector

arch/x86/mm/mem_encrypt.c

@@ -262,7 +262,7 @@ static void __init __set_clr_pte_enc(pte_t *kpte, int level, bool enc)
 	if (pgprot_val(old_prot) == pgprot_val(new_prot))
 		return;
 
-	pa = pfn << page_level_shift(level);
+	pa = pfn << PAGE_SHIFT;
 	size = page_level_size(level);
 
 	/*