x86/mm/sme, objtool: Annotate indirect call in sme_encrypt_execute()

This is boot code and thus Spectre-safe: we run this _way_ before userspace
comes along to have a chance to poison our branch predictor.

Signed-off-by: Peter Zijlstra (Intel) <[email protected]>
Acked-by: Thomas Gleixner <[email protected]>
Acked-by: Josh Poimboeuf <[email protected]>
Cc: Andy Lutomirski <[email protected]>
Cc: Arjan van de Ven <[email protected]>
Cc: Borislav Petkov <[email protected]>
Cc: Borislav Petkov <[email protected]>
Cc: Dan Williams <[email protected]>
Cc: Dave Hansen <[email protected]>
Cc: David Woodhouse <[email protected]>
Cc: Greg Kroah-Hartman <[email protected]>
Cc: Linus Torvalds <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Tom Lendacky <[email protected]>
Signed-off-by: Ingo Molnar <[email protected]>

diff --git a/arch/x86/mm/mem_encrypt_boot.S b/arch/x86/mm/mem_encrypt_boot.S
index 01f682cf77a8b36bff9a2b45a8f8beb734b4b6c4..40a6085063d6fe87958f260bf9cbc1be3b647424 100644 (file)
--- a/arch/x86/mm/mem_encrypt_boot.S
+++ b/arch/x86/mm/mem_encrypt_boot.S
@@ -15,6 +15,7 @@
 #include <asm/page.h>
 #include <asm/processor-flags.h>
 #include <asm/msr-index.h>
+#include <asm/nospec-branch.h>
 
        .text
        .code64
@@ -59,6 +60,7 @@ ENTRY(sme_encrypt_execute)
        movq    %rax, %r8               /* Workarea encryption routine */
        addq    $PAGE_SIZE, %r8         /* Workarea intermediate copy buffer */
 
+       ANNOTATE_RETPOLINE_SAFE
        call    *%rax                   /* Call the encryption routine */
 
        pop     %r12