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 <[email protected]>
---
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)
We've taken the change to ACPI_TO_POINTER.
Thanks,
Bob
-----Original Message-----
From: Qian Cai [mailto:[email protected]]
Sent: Thursday, July 18, 2019 12:49 PM
To: Wysocki, Rafael J <[email protected]>
Cc: Moore, Robert <[email protected]>; Schmauss, Erik <[email protected]>; [email protected]; [email protected]; [email protected]; [email protected]; [email protected]; [email protected]; [email protected]; Qian Cai <[email protected]>
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 <[email protected]>
---
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)
From: Moore, Robert
> Sent: 26 July 2019 20:36
...
> This is because pointer arithmetic
> on a pointer not pointing to an array is an undefined behavior (C11 6.5.6, constraint 8).
...
The standards committee as smoking dope again :-)
If that is enforced as a compiler warning/error a lot of code 'breaks'.
Anything that does:
struct foo *foo = ...;
struct bar *bar = (void *)(foo + 1);
suddenly becomes 'invalid'.
David
-
Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1PT, UK
Registration No: 1397386 (Wales)
> On Jul 29, 2019, at 6:24 AM, David Laight <[email protected]> wrote:
>
> From: Moore, Robert
>> Sent: 26 July 2019 20:36
> ...
>> This is because pointer arithmetic
>> on a pointer not pointing to an array is an undefined behavior (C11 6.5.6, constraint 8).
> ...
>
> The standards committee as smoking dope again :-)
> If that is enforced as a compiler warning/error a lot of code 'breaks'.
> Anything that does:
> struct foo *foo = ...;
> struct bar *bar = (void *)(foo + 1);
> suddenly becomes 'invalid’.
The clang will generate a warning only if “foo" is NULL.
> -----Original Message-----
> From: Qian Cai [mailto:[email protected]]
> Sent: Thursday, August 1, 2019 12:16 PM
> To: Moore, Robert <[email protected]>; Wysocki, Rafael J
> <[email protected]>
> Cc: Schmauss, Erik <[email protected]>; [email protected];
> [email protected]; [email protected]; [email protected];
> [email protected]; [email protected]; linux-
> [email protected]
> 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:[email protected]]
> > Sent: Thursday, July 18, 2019 12:49 PM
> > To: Wysocki, Rafael J <[email protected]>
> > Cc: Moore, Robert <[email protected]>; Schmauss, Erik
> > <erik.schmauss@inte l.com>; [email protected]; [email protected];
> > [email protected]; linux-acpi @vger.kernel.org;
> > [email protected]; [email protected]; linux-
> > [email protected]; Qian Cai <[email protected]>
> > 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 <[email protected]>
> > ---
> >
> > 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)
> >
-----Original Message-----
From: Schmauss, Erik
Sent: Thursday, August 01, 2019 1:18 PM
To: Qian Cai <[email protected]>; Moore, Robert <[email protected]>; Wysocki, Rafael J <[email protected]>
Cc: [email protected]; [email protected]; [email protected]; [email protected]; [email protected]; [email protected]; [email protected]
Subject: RE: [PATCH v2] acpica: fix -Wnull-pointer-arithmetic warnings
> -----Original Message-----
> From: Qian Cai [mailto:[email protected]]
> Sent: Thursday, August 1, 2019 12:16 PM
> To: Moore, Robert <[email protected]>; Wysocki, Rafael J
> <[email protected]>
> Cc: Schmauss, Erik <[email protected]>; [email protected];
> [email protected]; [email protected]; [email protected];
> [email protected]; [email protected]; linux-
> [email protected]
> 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
Which happens about once per month.
>Erik
>
> >
> >
> > -----Original Message-----
> > From: Qian Cai [mailto:[email protected]]
> > Sent: Thursday, July 18, 2019 12:49 PM
> > To: Wysocki, Rafael J <[email protected]>
> > Cc: Moore, Robert <[email protected]>; Schmauss, Erik
> > <erik.schmauss@inte l.com>; [email protected]; [email protected];
> > [email protected]; linux-acpi @vger.kernel.org;
> > [email protected]; [email protected]; linux-
> > [email protected]; Qian Cai <[email protected]>
> > 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 <[email protected]>
> > ---
> >
> > 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)
> >
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/02bbca5070e42d298c9b824300aa0eb8a082d797
but how does that change will go into the linux kernel? Suppose Rafael will need
to pick it up manually?
>
>
> -----Original Message-----
> From: Qian Cai [mailto:[email protected]]
> Sent: Thursday, July 18, 2019 12:49 PM
> To: Wysocki, Rafael J <[email protected]>
> Cc: Moore, Robert <[email protected]>; Schmauss, Erik <erik.schmauss@inte
> l.com>; [email protected]; [email protected]; [email protected]; linux-acpi
> @vger.kernel.org; [email protected]; [email protected]; linux-
> [email protected]; Qian Cai <[email protected]>
> 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 <[email protected]>
> ---
>
> 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)
>