Re: [PATCH v19 008/130] x86/tdx: Warning with 32bit build shift-count-overflow

Isaku Yamahata
2024-03-06T22:17:29Z

On Wed, Mar 06, 2024 at 10:35:43AM +1300,
"Huang, Kai" <kai.huang@intel.com> wrote:

>
>
> On 5/03/2024 9:12 pm, Isaku Yamahata wrote:
> > On Fri, Mar 01, 2024 at 01:36:43PM +0200,
> > "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> wrote:
> >
> > > On Thu, Feb 29, 2024 at 11:49:13AM +1300, Huang, Kai wrote:
> > > >
> > > >
> > > > On 26/02/2024 9:25 pm, isaku.yamahata@intel.com wrote:
> > > > > From: Isaku Yamahata <isaku.yamahata@intel.com>
> > > > >
> > > > > This patch fixes the following warnings.
> > > > >
> > > > > In file included from arch/x86/kernel/asm-offsets.c:22:
> > > > > arch/x86/include/asm/tdx.h:92:87: warning: shift count >= width of type [-Wshift-count-overflow]
> > > > > arch/x86/include/asm/tdx.h:20:21: note: expanded from macro 'TDX_ERROR'
> > > > > #define TDX_ERROR _BITUL(63)
> > > > >
> > > > > ^~~~~~~~~~
> > > > >
> > >
> > > I think you trim the warning message. I don't see the actual user of the
> > > define. Define itself will not generate the warning. You need to actually
> > > use it outside of preprocessor. I don't understand who would use it in
> > > 32-bit code. Maybe fixing it this way masking other issue.
> > >
> > > That said, I don't object the change itself. We just need to understand
> > > the context more.
> >
> > v18 used it as stub function. v19 dropped it as the stub was not needed.
>
> Sorry I literally don't understand what you are talking about here.
>
> Please just clarify (at least):
>
> - Does this problem exist in upstream code?

No.

> - If it does, what is the root cause, and how to reproduce?

v18 had a problem because it has stub function. v19 doesn't have problem because
it deleted the stub function.
--
Isaku Yamahata <isaku.yamahata@linux.intel.com>