| Message ID | 20190718194846.1880-1-cai@lca.pw (mailing list archive) |
|---|---|
| State | Not Applicable, archived |
| Headers | show |
| Series | [v2] acpica: fix -Wnull-pointer-arithmetic warnings | expand |
We've taken the change to ACPI_TO_POINTER. Thanks, Bob -----Original Message----- From: Qian Cai [mailto:cai@lca.pw] Sent: Thursday, July 18, 2019 12:49 PM To: Wysocki, Rafael J <rafael.j.wysocki@intel.com> Cc: Moore, Robert <robert.moore@intel.com>; Schmauss, Erik <erik.schmauss@intel.com>; jkim@FreeBSD.org; lenb@kernel.org; ndesaulniers@google.com; linux-acpi@vger.kernel.org; devel@acpica.org; clang-built-linux@googlegroups.com; linux-kernel@vger.kernel.org; Qian Cai <cai@lca.pw> 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@lca.pw> --- 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 <David.Laight@ACULAB.COM> 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.
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:cai@lca.pw] > Sent: Thursday, July 18, 2019 12:49 PM > To: Wysocki, Rafael J <rafael.j.wysocki@intel.com> > Cc: Moore, Robert <robert.moore@intel.com>; Schmauss, Erik <erik.schmauss@inte > l.com>; jkim@FreeBSD.org; lenb@kernel.org; ndesaulniers@google.com; linux-acpi > @vger.kernel.org; devel@acpica.org; clang-built-linux@googlegroups.com; linux- > kernel@vger.kernel.org; Qian Cai <cai@lca.pw> > 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@lca.pw> > --- > > 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: Qian Cai [mailto:cai@lca.pw] > Sent: Thursday, August 1, 2019 12:16 PM > To: Moore, Robert <robert.moore@intel.com>; Wysocki, Rafael J > <rafael.j.wysocki@intel.com> > Cc: Schmauss, Erik <erik.schmauss@intel.com>; jkim@FreeBSD.org; > lenb@kernel.org; ndesaulniers@google.com; linux-acpi@vger.kernel.org; > devel@acpica.org; clang-built-linux@googlegroups.com; linux- > kernel@vger.kernel.org > 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@lca.pw] > > Sent: Thursday, July 18, 2019 12:49 PM > > To: Wysocki, Rafael J <rafael.j.wysocki@intel.com> > > Cc: Moore, Robert <robert.moore@intel.com>; Schmauss, Erik > > <erik.schmauss@inte l.com>; jkim@FreeBSD.org; lenb@kernel.org; > > ndesaulniers@google.com; linux-acpi @vger.kernel.org; > > devel@acpica.org; clang-built-linux@googlegroups.com; linux- > > kernel@vger.kernel.org; Qian Cai <cai@lca.pw> > > 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@lca.pw> > > --- > > > > 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 <cai@lca.pw>; Moore, Robert <robert.moore@intel.com>; Wysocki, Rafael J <rafael.j.wysocki@intel.com> Cc: jkim@FreeBSD.org; lenb@kernel.org; ndesaulniers@google.com; linux-acpi@vger.kernel.org; devel@acpica.org; clang-built-linux@googlegroups.com; linux-kernel@vger.kernel.org Subject: RE: [PATCH v2] acpica: fix -Wnull-pointer-arithmetic warnings > -----Original Message----- > From: Qian Cai [mailto:cai@lca.pw] > Sent: Thursday, August 1, 2019 12:16 PM > To: Moore, Robert <robert.moore@intel.com>; Wysocki, Rafael J > <rafael.j.wysocki@intel.com> > Cc: Schmauss, Erik <erik.schmauss@intel.com>; jkim@FreeBSD.org; > lenb@kernel.org; ndesaulniers@google.com; linux-acpi@vger.kernel.org; > devel@acpica.org; clang-built-linux@googlegroups.com; linux- > kernel@vger.kernel.org > 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:cai@lca.pw] > > Sent: Thursday, July 18, 2019 12:49 PM > > To: Wysocki, Rafael J <rafael.j.wysocki@intel.com> > > Cc: Moore, Robert <robert.moore@intel.com>; Schmauss, Erik > > <erik.schmauss@inte l.com>; jkim@FreeBSD.org; lenb@kernel.org; > > ndesaulniers@google.com; linux-acpi @vger.kernel.org; > > devel@acpica.org; clang-built-linux@googlegroups.com; linux- > > kernel@vger.kernel.org; Qian Cai <cai@lca.pw> > > 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@lca.pw> > > --- > > > > 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) > >
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)
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@lca.pw> --- v2: Use ACPI_CAST_PTR() in ACPI_TO_POINTER() directly without arithmetic. include/acpi/actypes.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)