lkml.org 
[lkml]   [2020]   [Jun]   [16]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
From
SubjectRE: [Devel] Re: [PATCH] ACPICA: fix UBSAN warning using __builtin_offsetof
Date


> -----Original Message-----
> From: Nick Desaulniers <ndesaulniers@google.com>
> Sent: Thursday, June 11, 2020 10:06 AM
> To: Kaneda, Erik <erik.kaneda@intel.com>
> Cc: Jung-uk Kim <jkim@freebsd.org>; Wysocki, Rafael J
> <rafael.j.wysocki@intel.com>; Ard Biesheuvel <ardb@kernel.org>;
> dvyukov@google.com; glider@google.com; linux-arm-
> kernel@lists.infradead.org; linux-kernel@vger.kernel.org;
> lorenzo.pieralisi@arm.com; mark.rutland@arm.com; pcc@google.com;
> rjw@rjwysocki.net; will@kernel.org; stable@vger.kernel.org; linux-
> acpi@vger.kernel.org; devel@acpica.org
> Subject: Re: [Devel] Re: [PATCH] ACPICA: fix UBSAN warning using
> __builtin_offsetof
>
> On Thu, Jun 11, 2020 at 9:45 AM Kaneda, Erik <erik.kaneda@intel.com>
> wrote:
> >
> > > From: Jung-uk Kim <jkim@FreeBSD.org>
> > >
> > > Actually, I think we should let platform-specific acfoo.h decide what to
> > > do here, i.e.,
> >
> > That's a better solution. For Linux, it would look something like this:
> >
> > --- a/include/acpi/actypes.h
> > +++ b/include/acpi/actypes.h
> > @@ -508,10 +508,15 @@ typedef u64 acpi_integer;
> >
> > #define ACPI_TO_POINTER(i) ACPI_CAST_PTR (void, (acpi_size) (i))
> > #define ACPI_TO_INTEGER(p) ACPI_PTR_DIFF (p, (void *) 0)
> > -#define ACPI_OFFSET(d, f) ACPI_PTR_DIFF (&(((d *) 0)->f), (void *)
> 0)
> > #define ACPI_PHYSADDR_TO_PTR(i) ACPI_TO_POINTER(i)
> > #define ACPI_PTR_TO_PHYSADDR(i) ACPI_TO_INTEGER(i)
> >
> > +/* Platforms may want to define their own ACPI_OFFSET */
> > +
> > +#ifndef ACPI_OFFSET
> > +#define ACPI_OFFSET(d, f) ACPI_PTR_DIFF (&(((d *) 0)->f), (void
> *) 0)
> > +#endif
> > +
> > /* Optimizations for 4-character (32-bit) acpi_name manipulation */
> >
> > #ifndef ACPI_MISALIGNMENT_NOT_SUPPORTED
> > diff --git a/include/acpi/platform/aclinux.h
> b/include/acpi/platform/aclinux.h
> > index 987e2af7c335..5d1ca6015fce 100644
> > --- a/include/acpi/platform/aclinux.h
> > +++ b/include/acpi/platform/aclinux.h
> > @@ -71,6 +71,11 @@
> > #undef ACPI_DEBUG_DEFAULT
> > #define ACPI_DEBUG_DEFAULT (ACPI_LV_INFO | ACPI_LV_REPAIR)
> >
> > +/* Use gcc's builtin offset instead of the default */
> > +
> > +#undef ACPI_OFFSET
> > +#define ACPI_OFFSET(a,b) __builtin_offsetof(a,b)
> > +
> > #ifndef CONFIG_ACPI
> >
>
Hi,

Sorry about the delayed response.

> Looks good at first glance. Wouldn't actypes.h need to include
> platform/acenv.h first though? Otherwise you put some header
> inclusion order dependency on folks who include actypes.h to first
> include acenv.h otherwise we're not getting the definition in terms of
> __builtin_offsetof.

Actypes.h is intended for ACPICA use. For files using ACPI_OFFSET, they include headers like acpi.h that ends up including aclinux.h before including actypes.h. For those using ACPI_OFFSET, precedence will be given to the definition in aclinux.h before falling back to the definition in actypes.

Erik

>
> --
> Thanks,
> ~Nick Desaulniers
\
 
 \ /
  Last update: 2020-06-16 23:41    [W:1.560 / U:0.588 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site