On Wed, Apr 10, 2019 at 02:13:34PM -0700, Nadav Amit wrote: > Untested, but clearly bit 12 is the one that needs to be tested. > > Signed-off-by: Nadav Amit <nadav.amit@xxxxxxxxx> > --- > x86/cstart64.S | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/x86/cstart64.S b/x86/cstart64.S > index 21db10f..8626f02 100644 > --- a/x86/cstart64.S > +++ b/x86/cstart64.S > @@ -243,7 +243,7 @@ start64: > setup_5level_page_table: > /* Check if 5-level paging has already enabled */ > mov %cr4, %rax > - test $12, %eax > + bt $12, %eax > jnz lvl5 Unfortunately BT doesn't affect RFLAGS.ZF, so 'jnz' needs to be changed to 'jc'. Or alternatively, do 'test $1000, %eax'. > > pushq $32 > -- > 2.17.1 >
