> On 2014-04-26, Miod Vallat <m...@online.fr> wrote: > >> The question I have is can I disable the random number generator?s use of > >> that instruction? I?d rather be on -current than years old. > > > > Apart from the following hammer, I see no easy way to achieve this. > > > > Index: i386/machdep.c > >=================================================================== > > RCS file: /cvs/src/sys/arch/i386/i386/machdep.c,v > > retrieving revision 1.536 > > diff -u -p -r1.536 machdep.c > > --- i386/machdep.c 29 Mar 2014 18:09:29 -0000 1.536 > > +++ i386/machdep.c 26 Apr 2014 19:13:14 -0000 > > @@ -1964,7 +1964,8 @@ identifycpu(struct cpu_info *ci) > > } > > > > if (ci->ci_flags & CPUF_PRIMARY) { > > - if (cpu_ecxfeature & CPUIDECX_RDRAND) > > + if (cpu_ecxfeature & CPUIDECX_RDRAND && > > + vendor != CPUVENDOR_CYRIX) > > has_rdrand = 1; > > #ifndef SMALL_KERNEL > > if (ci->ci_feature_sefflags & SEFF0EBX_SMAP) > > > > > > Funnily enough it's handled here:
Then this ought to work as well: Index: i386/locore.s =================================================================== RCS file: /cvs/src/sys/arch/i386/i386/locore.s,v retrieving revision 1.147 diff -u -p -r1.147 locore.s --- i386/locore.s 13 Jun 2013 02:26:53 -0000 1.147 +++ i386/locore.s 26 Apr 2014 21:21:01 -0000 @@ -401,6 +401,7 @@ try586: /* Use the `cpuid' instruction. movl $0, RELOC(_C_LABEL(cpu_vendor))+12 movl $1,%eax + xorl %ecx,%ecx cpuid movl %eax,RELOC(_C_LABEL(cpu_id)) # store cpu_id and features movl %ebx,RELOC(_C_LABEL(cpu_miscinfo))