Gentle ping. I would appreciate quick feedback if this approach is reasonable. Peter: since you suggested that we should not change objtool, did you have a particular approach in mind that is maybe different from v2 and v3? Or is this what you were thinking of? Many thanks! On Fri, 31 May 2019 at 17:11, Marco Elver <elver@xxxxxxxxxx> wrote: > > This patch is a pre-requisite for enabling KASAN bitops instrumentation; > using static_cpu_has instead of boot_cpu_has avoids instrumentation of > test_bit inside the uaccess region. With instrumentation, the KASAN > check would otherwise be flagged by objtool. > > For consistency, kernel/signal.c was changed to mirror this change, > however, is never instrumented with KASAN (currently unsupported under > x86 32bit). > > Signed-off-by: Marco Elver <elver@xxxxxxxxxx> > Suggested-by: H. Peter Anvin <hpa@xxxxxxxxx> > --- > Changes in v3: > * Use static_cpu_has instead of moving boot_cpu_has outside uaccess > region. > > Changes in v2: > * Replaces patch: 'tools/objtool: add kasan_check_* to uaccess > whitelist' > --- > arch/x86/ia32/ia32_signal.c | 2 +- > arch/x86/kernel/signal.c | 2 +- > 2 files changed, 2 insertions(+), 2 deletions(-) > > diff --git a/arch/x86/ia32/ia32_signal.c b/arch/x86/ia32/ia32_signal.c > index 629d1ee05599..1cee10091b9f 100644 > --- a/arch/x86/ia32/ia32_signal.c > +++ b/arch/x86/ia32/ia32_signal.c > @@ -358,7 +358,7 @@ int ia32_setup_rt_frame(int sig, struct ksignal *ksig, > put_user_ex(ptr_to_compat(&frame->uc), &frame->puc); > > /* Create the ucontext. */ > - if (boot_cpu_has(X86_FEATURE_XSAVE)) > + if (static_cpu_has(X86_FEATURE_XSAVE)) > put_user_ex(UC_FP_XSTATE, &frame->uc.uc_flags); > else > put_user_ex(0, &frame->uc.uc_flags); > diff --git a/arch/x86/kernel/signal.c b/arch/x86/kernel/signal.c > index 364813cea647..52eb1d551aed 100644 > --- a/arch/x86/kernel/signal.c > +++ b/arch/x86/kernel/signal.c > @@ -391,7 +391,7 @@ static int __setup_rt_frame(int sig, struct ksignal *ksig, > put_user_ex(&frame->uc, &frame->puc); > > /* Create the ucontext. */ > - if (boot_cpu_has(X86_FEATURE_XSAVE)) > + if (static_cpu_has(X86_FEATURE_XSAVE)) > put_user_ex(UC_FP_XSTATE, &frame->uc.uc_flags); > else > put_user_ex(0, &frame->uc.uc_flags); > -- > 2.22.0.rc1.257.g3120a18244-goog >
