> On Feb 5, 2018, at 3:42 AM, Ingo Molnar <[email protected]> wrote: > > > * Dan Williams <[email protected]> wrote: > >> + /* >> + * Sanitize extra registers of values that a speculation attack >> + * might want to exploit. In the CONFIG_FRAME_POINTER=y case, >> + * the expectation is that %ebp will be clobbered before it >> + * could be used. >> + */ >> + .macro CLEAR_EXTRA_REGS_NOSPEC >> + xorq %r15, %r15 >> + xorq %r14, %r14 >> + xorq %r13, %r13 >> + xorq %r12, %r12 >> + xorl %ebx, %ebx >> +#ifndef CONFIG_FRAME_POINTER >> + xorl %ebp, %ebp >> +#endif >> + .endm > > Yeah, so this series look pretty good to me, but there's one small detail: I > think > RBP should be cleared unconditionally here, even in the > CONFIG_FRAME_POINTERS=y > case, because:
ENCODE_FRAME_POINTER should take care of rbp, though.
