I can take this patch as-is, I think. I'll try for the next acpica release later this week. -----Original Message----- From: Wysocki, Rafael J <rafael.j.wysocki@xxxxxxxxx> Sent: Tuesday, September 28, 2021 10:44 AM To: Arnd Bergmann <arnd@xxxxxxxxxx>; Moore, Robert <robert.moore@xxxxxxxxx> Cc: Arnd Bergmann <arnd@xxxxxxxx>; Nathan Chancellor <nathan@xxxxxxxxxx>; Nick Desaulniers <ndesaulniers@xxxxxxxxxx>; Erik Kaneda <erik.kaneda@xxxxxxxxx>; linux-acpi@xxxxxxxxxxxxxxx; devel@xxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx; llvm@xxxxxxxxxxxxxxx; Len Brown <lenb@xxxxxxxxxx>; Rafael J. Wysocki <rafael@xxxxxxxxxx> Subject: Re: [PATCH] ACPI: avoid NULL pointer arithmetic Bob, this is ACPICA material. Would it be possible to apply this to the upstream from the patch or do you need a PR for this? On 9/27/2021 2:13 PM, Arnd Bergmann wrote: > From: Arnd Bergmann <arnd@xxxxxxxx> > > There are some very old macros for doing an open-coded offsetof() and > cast between pointer and integer in ACPI headers. clang-14 now > complains about these: > > drivers/acpi/acpica/tbfadt.c:86:3: error: performing pointer subtraction with a null pointer has undefined behavior [-Werror,-Wnull-pointer-subtraction] > ACPI_FADT_OFFSET(pm_timer_block), > ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ > include/acpi/actbl.h:376:47: note: expanded from macro 'ACPI_FADT_OFFSET' > #define ACPI_FADT_OFFSET(f) (u16) ACPI_OFFSET (struct acpi_table_fadt, f) > > ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ > include/acpi/actypes.h:511:41: note: expanded from macro 'ACPI_OFFSET' > #define ACPI_OFFSET(d, f) ACPI_PTR_DIFF (&(((d *) 0)->f), (void *) 0) > > ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ > include/acpi/actypes.h:505:79: note: expanded from macro 'ACPI_PTR_DIFF' > #define ACPI_PTR_DIFF(a, b) ((acpi_size) (ACPI_CAST_PTR (u8, (a)) - ACPI_CAST_PTR (u8, (b)))) > > ^ ~~~~~~~~~~~~~~~~~~~~~~~ Convert them to the modern equivalents. > > Signed-off-by: Arnd Bergmann <arnd@xxxxxxxx> > --- > include/acpi/actypes.h | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > diff --git a/include/acpi/actypes.h b/include/acpi/actypes.h index > 92c71dfce0d5..285bc7b73de3 100644 > --- a/include/acpi/actypes.h > +++ b/include/acpi/actypes.h > @@ -507,8 +507,8 @@ typedef u64 acpi_integer; > /* Pointer/Integer type conversions */ > > #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_TO_INTEGER(p) ((uintptr_t)(p)) > +#define ACPI_OFFSET(d, f) offsetof(d, f) > #define ACPI_PHYSADDR_TO_PTR(i) ACPI_TO_POINTER(i) > #define ACPI_PTR_TO_PHYSADDR(i) ACPI_TO_INTEGER(i) >
