> -----Original Message----- > From: Qian Cai [mailto:cai@xxxxxx] > Sent: Thursday, August 1, 2019 12:16 PM > To: Moore, Robert <robert.moore@xxxxxxxxx>; Wysocki, Rafael J > <rafael.j.wysocki@xxxxxxxxx> > Cc: Schmauss, Erik <erik.schmauss@xxxxxxxxx>; jkim@xxxxxxxxxxx; > lenb@xxxxxxxxxx; ndesaulniers@xxxxxxxxxx; linux-acpi@xxxxxxxxxxxxxxx; > devel@xxxxxxxxxx; clang-built-linux@xxxxxxxxxxxxxxxx; linux- > kernel@xxxxxxxxxxxxxxx > Subject: Re: [PATCH v2] acpica: fix -Wnull-pointer-arithmetic warnings > > On Fri, 2019-07-26 at 19:35 +0000, Moore, Robert wrote: > > We've taken the change to ACPI_TO_POINTER. > > I am a bit confused here. I saw the commit in the acpia repo. > > https://github.com/acpica/acpica/commit/02bbca5070e42d298c9b824300aa0 > eb8a082d797 > > but how does that change will go into the linux kernel? Suppose Rafael will > need to pick it up manually? I do that after every ACPICA release Erik > > > > > > > -----Original Message----- > > From: Qian Cai [mailto:cai@xxxxxx] > > Sent: Thursday, July 18, 2019 12:49 PM > > To: Wysocki, Rafael J <rafael.j.wysocki@xxxxxxxxx> > > Cc: Moore, Robert <robert.moore@xxxxxxxxx>; Schmauss, Erik > > <erik.schmauss@inte l.com>; jkim@xxxxxxxxxxx; lenb@xxxxxxxxxx; > > ndesaulniers@xxxxxxxxxx; linux-acpi @vger.kernel.org; > > devel@xxxxxxxxxx; clang-built-linux@xxxxxxxxxxxxxxxx; linux- > > kernel@xxxxxxxxxxxxxxx; Qian Cai <cai@xxxxxx> > > Subject: [PATCH v2] acpica: fix -Wnull-pointer-arithmetic warnings > > > > Clang generate quite a few of those warnings. > > > > drivers/acpi/scan.c:759:28: warning: arithmetic on a null pointer > > treated as a cast from integer to pointer is a GNU extension [-Wnull-pointer- > arithmetic] > > status = acpi_get_handle(ACPI_ROOT_OBJECT, > > obj->string.pointer, > > ^~~~~~~~~~~~~~~~ > > ./include/acpi/actypes.h:458:56: note: expanded from macro > 'ACPI_ROOT_OBJECT' > > #define ACPI_ROOT_OBJECT ((acpi_handle) > > ACPI_TO_POINTER > > (ACPI_MAX_PTR)) > > ^~~~~~~~~~~~~~~ > > ./include/acpi/actypes.h:509:41: note: expanded from macro > 'ACPI_TO_POINTER' > > #define ACPI_TO_POINTER(i) ACPI_ADD_PTR (void, (void *) > > 0, > > (acpi_size) (i)) > > > > ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ > > ./include/acpi/actypes.h:503:84: note: expanded from macro 'ACPI_ADD_PTR' > > #define ACPI_ADD_PTR(t, a, b) ACPI_CAST_PTR (t, > > (ACPI_CAST_PTR (u8, (a)) + (acpi_size)(b))) > > ^~~~~~~~~~~~~~~~~ > > ./include/acpi/actypes.h:501:66: note: expanded from macro > 'ACPI_CAST_PTR' > > #define ACPI_CAST_PTR(t, p) ((t *) (acpi_uintptr_t) (p)) > > ^ > > This is because pointer arithmetic on a pointer not pointing to an > > array is an undefined behavior (C11 6.5.6, constraint 8). Fix it by > > just casting the corresponding pointers using ACPI_CAST_PTR() and skip > > the arithmetic. Also, fix a checkpatch warning together. > > > > ERROR: Macros with complex values should be enclosed in parentheses > > #45: FILE: include/acpi/actypes.h:509: > > +#define ACPI_TO_POINTER(i) ACPI_CAST_PTR (void, i) > > > > Signed-off-by: Qian Cai <cai@xxxxxx> > > --- > > > > v2: Use ACPI_CAST_PTR() in ACPI_TO_POINTER() directly without > > arithmetic. > > > > include/acpi/actypes.h | 2 +- > > 1 file changed, 1 insertion(+), 1 deletion(-) > > > > diff --git a/include/acpi/actypes.h b/include/acpi/actypes.h index > > ad6892a24015..163181e2d884 100644 > > --- a/include/acpi/actypes.h > > +++ b/include/acpi/actypes.h > > @@ -506,7 +506,7 @@ typedef u64 acpi_integer; > > > > /* Pointer/Integer type conversions */ > > > > -#define ACPI_TO_POINTER(i) ACPI_ADD_PTR (void, (void *) > > 0, > > (acpi_size) (i)) > > +#define ACPI_TO_POINTER(i) (ACPI_CAST_PTR (void, 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) > > -- > > 2.20.1 (Apple Git-117) > >
