On Fri, Nov 17, 2017 at 08:10:13PM +0100, Juergen Gross wrote: > On 17/11/17 19:07, Borislav Petkov wrote: > > On Wed, Oct 04, 2017 at 10:58:24AM -0500, Josh Poimboeuf wrote: > >> Convert the hard-coded native patch assembly code strings to macros to > >> facilitate sharing common code between 32-bit and 64-bit. > >> > >> These macros will also be used by a future patch which requires the GCC > >> extended asm syntax of two '%' characters instead of one when specifying > >> a register name. > >> > >> Signed-off-by: Josh Poimboeuf <jpoimboe@xxxxxxxxxx> > >> --- > >> arch/x86/include/asm/special_insns.h | 24 ++++++++++++++++++++++++ > >> arch/x86/kernel/paravirt_patch_32.c | 21 +++++++++++---------- > >> arch/x86/kernel/paravirt_patch_64.c | 29 +++++++++++++++-------------- > >> 3 files changed, 50 insertions(+), 24 deletions(-) > >> > >> diff --git a/arch/x86/include/asm/special_insns.h b/arch/x86/include/asm/special_insns.h > >> index ac402c6fc24b..0549c5f2c1b3 100644 > >> --- a/arch/x86/include/asm/special_insns.h > >> +++ b/arch/x86/include/asm/special_insns.h > >> @@ -6,6 +6,30 @@ > >> > >> #include <asm/nops.h> > >> > >> +#ifdef CONFIG_X86_64 > >> +# define _REG_ARG1 "%rdi" > >> +# define NATIVE_IDENTITY_32 "mov %edi, %eax" > > > > Yeah, that "identity" looks strange. How about NATIVE_NOOP and > > NATIVE_NOOP_32 ? > > Those are not NOPs. They return the identical value which was passed to > them. So identity isn't a bad name after all. Right, like the math identity function: https://en.wikipedia.org/wiki/Identity_function > >> +# define NATIVE_USERGS_SYSRET64 "swapgs; sysretq" > >> +#else > >> +# define _REG_ARG1 "%eax" > >> +#endif > >> + > >> +#define _REG_RET "%" _ASM_AX > >> + > >> +#define NATIVE_ZERO "xor " _REG_ARG1 ", " _REG_ARG1 > > > > NATIVE_ZERO_OUT > > > > I guess. NATIVE_ZERO reads like the native representation of 0 :-) > > NATIVE_ZERO_ARG1? On a slight tangent, does anybody know why it zeros the arg? The only place it's used is here: #if defined(CONFIG_PARAVIRT_SPINLOCKS) DEF_NATIVE(pv_lock_ops, queued_spin_unlock, NATIVE_QUEUED_SPIN_UNLOCK); DEF_NATIVE(pv_lock_ops, vcpu_is_preempted, NATIVE_ZERO); #endif Isn't that a bug? Seems like it should _return_ zero. Zeroing the arg shouldn't have any effect. If I'm right, we could call it NATIVE_FALSE. -- Josh _______________________________________________ Virtualization mailing list Virtualization@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linuxfoundation.org/mailman/listinfo/virtualization
