| Message ID | 20170627093320.9811-2-julien.grall@arm.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
At 10:33 +0100 on 27 Jun (1498559600), Julien Grall wrote: > The current implementation of {G,M}FN_INVALID cannot be used to > initialize global variable because the initializer element is not a > constant. > > Due to a bug in GCC 4.9 and older ([1]), it is not easy to find a common > value to initialize a variable and directly passed as an argument. > > Introduce 2 news define {G,M}FN_INVALID_INITIALIZER to be used for > initializing a variable. > > [1] https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64856 > > Signed-off-by: Julien Grall <julien.grall@arm.com> Acked-by: Tim Deegan <tim@xen.org> (and Ack for the revert too) but please choose either { ~0UL } or {~0UL} and use it for both. > --- > Build tested it with: > * ARM: GCC 4.9.4, 5.1, 4.3, 6.1.1, 7.1.0 > * x86: Clang 3.5.0, 3.6.0, 3.6.2, 3.8.0, 3.9.0, 4.0.0 > > With introducing a dummy global variable common/mm.c: > > mfn_t foo = INVALID_MFN_INITIALIZER > --- > xen/include/xen/mm.h | 10 ++++++++++ > 1 file changed, 10 insertions(+) > > diff --git a/xen/include/xen/mm.h b/xen/include/xen/mm.h > index 0050fba498..251db4ffa1 100644 > --- a/xen/include/xen/mm.h > +++ b/xen/include/xen/mm.h > @@ -57,6 +57,11 @@ > TYPE_SAFE(unsigned long, mfn); > #define PRI_mfn "05lx" > #define INVALID_MFN _mfn(~0UL) > +/* > + * To be used for global variable initialization. This workaround a bug > + * in GCC < 5.0. > + */ > +#define INVALID_MFN_INITIALIZER {~0UL} > > #ifndef mfn_t > #define mfn_t /* Grep fodder: mfn_t, _mfn() and mfn_x() are defined above */ > @@ -90,6 +95,11 @@ static inline bool_t mfn_eq(mfn_t x, mfn_t y) > TYPE_SAFE(unsigned long, gfn); > #define PRI_gfn "05lx" > #define INVALID_GFN _gfn(~0UL) > +/* > + * To be used for global variable initialization. This workaround a bug > + * in GCC < 5.0 https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64856 > + */ > +#define INVALID_GFN_INITIALIZER { ~0UL } > > #ifndef gfn_t > #define gfn_t /* Grep fodder: gfn_t, _gfn() and gfn_x() are defined above */ > -- > 2.11.0 >
On 27/06/2017 10:46, Tim Deegan wrote: > At 10:33 +0100 on 27 Jun (1498559600), Julien Grall wrote: >> The current implementation of {G,M}FN_INVALID cannot be used to >> initialize global variable because the initializer element is not a >> constant. >> >> Due to a bug in GCC 4.9 and older ([1]), it is not easy to find a common >> value to initialize a variable and directly passed as an argument. >> >> Introduce 2 news define {G,M}FN_INVALID_INITIALIZER to be used for >> initializing a variable. >> >> [1] https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64856 >> >> Signed-off-by: Julien Grall <julien.grall@arm.com> > > Acked-by: Tim Deegan <tim@xen.org> (and Ack for the revert too) > but please choose either { ~0UL } or {~0UL} and use it for both. Whoops. Sorry for that. I will stick to {~0UL} unless someone prefer the { ~0UL }. Cheers, > >> --- >> Build tested it with: >> * ARM: GCC 4.9.4, 5.1, 4.3, 6.1.1, 7.1.0 >> * x86: Clang 3.5.0, 3.6.0, 3.6.2, 3.8.0, 3.9.0, 4.0.0 >> >> With introducing a dummy global variable common/mm.c: >> >> mfn_t foo = INVALID_MFN_INITIALIZER >> --- >> xen/include/xen/mm.h | 10 ++++++++++ >> 1 file changed, 10 insertions(+) >> >> diff --git a/xen/include/xen/mm.h b/xen/include/xen/mm.h >> index 0050fba498..251db4ffa1 100644 >> --- a/xen/include/xen/mm.h >> +++ b/xen/include/xen/mm.h >> @@ -57,6 +57,11 @@ >> TYPE_SAFE(unsigned long, mfn); >> #define PRI_mfn "05lx" >> #define INVALID_MFN _mfn(~0UL) >> +/* >> + * To be used for global variable initialization. This workaround a bug >> + * in GCC < 5.0. >> + */ >> +#define INVALID_MFN_INITIALIZER {~0UL} >> >> #ifndef mfn_t >> #define mfn_t /* Grep fodder: mfn_t, _mfn() and mfn_x() are defined above */ >> @@ -90,6 +95,11 @@ static inline bool_t mfn_eq(mfn_t x, mfn_t y) >> TYPE_SAFE(unsigned long, gfn); >> #define PRI_gfn "05lx" >> #define INVALID_GFN _gfn(~0UL) >> +/* >> + * To be used for global variable initialization. This workaround a bug >> + * in GCC < 5.0 https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64856 >> + */ >> +#define INVALID_GFN_INITIALIZER { ~0UL } >> >> #ifndef gfn_t >> #define gfn_t /* Grep fodder: gfn_t, _gfn() and gfn_x() are defined above */ >> -- >> 2.11.0 >>
Hi, On 06/27/2017 10:47 AM, Julien Grall wrote: > > > On 27/06/2017 10:46, Tim Deegan wrote: >> At 10:33 +0100 on 27 Jun (1498559600), Julien Grall wrote: >>> The current implementation of {G,M}FN_INVALID cannot be used to >>> initialize global variable because the initializer element is not a >>> constant. >>> >>> Due to a bug in GCC 4.9 and older ([1]), it is not easy to find a common >>> value to initialize a variable and directly passed as an argument. >>> >>> Introduce 2 news define {G,M}FN_INVALID_INITIALIZER to be used for >>> initializing a variable. >>> >>> [1] https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64856 >>> >>> Signed-off-by: Julien Grall <julien.grall@arm.com> >> >> Acked-by: Tim Deegan <tim@xen.org> (and Ack for the revert too) >> but please choose either { ~0UL } or {~0UL} and use it for both. > > Whoops. Sorry for that. I will stick to {~0UL} unless someone prefer the > { ~0UL }. Also, shall I resent a patch with this change? Or will it get taken care on commit? (assuming there are no other changes). Cheers,
On 29/06/17 17:30, Julien Grall wrote: > Hi, > > On 06/27/2017 10:47 AM, Julien Grall wrote: >> >> >> On 27/06/2017 10:46, Tim Deegan wrote: >>> At 10:33 +0100 on 27 Jun (1498559600), Julien Grall wrote: >>>> The current implementation of {G,M}FN_INVALID cannot be used to >>>> initialize global variable because the initializer element is not a >>>> constant. >>>> >>>> Due to a bug in GCC 4.9 and older ([1]), it is not easy to find a >>>> common >>>> value to initialize a variable and directly passed as an argument. >>>> >>>> Introduce 2 news define {G,M}FN_INVALID_INITIALIZER to be used for >>>> initializing a variable. >>>> >>>> [1] https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64856 >>>> >>>> Signed-off-by: Julien Grall <julien.grall@arm.com> >>> >>> Acked-by: Tim Deegan <tim@xen.org> (and Ack for the revert too) >>> but please choose either { ~0UL } or {~0UL} and use it for both. >> >> Whoops. Sorry for that. I will stick to {~0UL} unless someone prefer >> the { ~0UL }. > > Also, shall I resent a patch with this change? Or will it get taken > care on commit? (assuming there are no other changes). I'll sort it out on commit, when I do my next sweep (if someone doesn't beat me to it). ~Andrew
diff --git a/xen/include/xen/mm.h b/xen/include/xen/mm.h index 0050fba498..251db4ffa1 100644 --- a/xen/include/xen/mm.h +++ b/xen/include/xen/mm.h @@ -57,6 +57,11 @@ TYPE_SAFE(unsigned long, mfn); #define PRI_mfn "05lx" #define INVALID_MFN _mfn(~0UL) +/* + * To be used for global variable initialization. This workaround a bug + * in GCC < 5.0. + */ +#define INVALID_MFN_INITIALIZER {~0UL} #ifndef mfn_t #define mfn_t /* Grep fodder: mfn_t, _mfn() and mfn_x() are defined above */ @@ -90,6 +95,11 @@ static inline bool_t mfn_eq(mfn_t x, mfn_t y) TYPE_SAFE(unsigned long, gfn); #define PRI_gfn "05lx" #define INVALID_GFN _gfn(~0UL) +/* + * To be used for global variable initialization. This workaround a bug + * in GCC < 5.0 https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64856 + */ +#define INVALID_GFN_INITIALIZER { ~0UL } #ifndef gfn_t #define gfn_t /* Grep fodder: gfn_t, _gfn() and gfn_x() are defined above */
The current implementation of {G,M}FN_INVALID cannot be used to initialize global variable because the initializer element is not a constant. Due to a bug in GCC 4.9 and older ([1]), it is not easy to find a common value to initialize a variable and directly passed as an argument. Introduce 2 news define {G,M}FN_INVALID_INITIALIZER to be used for initializing a variable. [1] https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64856 Signed-off-by: Julien Grall <julien.grall@arm.com> --- Build tested it with: * ARM: GCC 4.9.4, 5.1, 4.3, 6.1.1, 7.1.0 * x86: Clang 3.5.0, 3.6.0, 3.6.2, 3.8.0, 3.9.0, 4.0.0 With introducing a dummy global variable common/mm.c: mfn_t foo = INVALID_MFN_INITIALIZER --- xen/include/xen/mm.h | 10 ++++++++++ 1 file changed, 10 insertions(+)