Merge branch 'x86-pti-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git...

[linux-2.6-microblaze.git] / arch / x86 / include / asm / processor.h

diff --git a/arch/x86/include/asm/processor.h b/arch/x86/include/asm/processor.h
index c7a4e2a..6178059 100644 (file)
--- a/arch/x86/include/asm/processor.h
+++ b/arch/x86/include/asm/processor.h
@@ -316,7 +316,13 @@ struct x86_hw_tss {
         */
        u64                     sp1;
 
+       /*
+        * Since Linux does not use ring 2, the 'sp2' slot is unused by
+        * hardware.  entry_SYSCALL_64 uses it as scratch space to stash
+        * the user RSP value.
+        */
        u64                     sp2;
+
        u64                     reserved2;
        u64                     ist[7];
        u32                     reserved3;