Re: [PATCH v23 6/9] x86/entry: Introduce ENDBR macro

On 3/16/2021 10:30 AM, Borislav Petkov wrote:

On Tue, Mar 16, 2021 at 10:12:39AM -0700, Yu, Yu-cheng wrote:

quoted

Alternatively, there is another compiler-defined macro _CET_ENDBR that can
be used.  We can put the following in calling.h:

Not calling.h - this is apparently needed in vdso code only so I guess
some header there, arch/x86/include/asm/vdso.h maybe? In the

#else /* __ASSEMBLER__ */

branch maybe...

quoted

#ifdef __CET__
#include <cet.h>
#else
#define _CET_ENDBR
#endif

and then use _CET_ENDBR in other files.  How is that?

What does that macro do? Issue an ENDBR only?

Yes, issue endbr32, endbr64, or nothing when cet is not enabled.