* [PATCH 1/2] Correct function definition for C++ @ 2017-02-21 15:24 Joakim Tjernlund 2017-02-21 15:24 ` [PATCH 2/2] compiler.h: fix C++ uninitialized const issue Joakim Tjernlund 2017-02-22 7:10 ` [PATCH 1/2] Correct function definition for C++ Greg KH 0 siblings, 2 replies; 9+ messages in thread From: Joakim Tjernlund @ 2017-02-21 15:24 UTC (permalink / raw) To: linux-kernel, stable; +Cc: Joakim Tjernlund C++ does does not like the extra extern before asmlinkage, remove it. Signed-off-by: Joakim Tjernlund <joakim.tjernlund@infinera.com> --- include/linux/printk.h | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/include/linux/printk.h b/include/linux/printk.h index 3472cc6..be823f5 100644 --- a/include/linux/printk.h +++ b/include/linux/printk.h @@ -139,7 +139,7 @@ struct va_format { }) #ifdef CONFIG_EARLY_PRINTK -extern asmlinkage __printf(1, 2) +asmlinkage __printf(1, 2) void early_printk(const char *fmt, ...); #else static inline __printf(1, 2) __cold @@ -270,7 +270,7 @@ static inline void show_regs_print_info(const char *log_lvl) } #endif -extern asmlinkage void dump_stack(void) __cold; +asmlinkage void dump_stack(void) __cold; #ifndef pr_fmt #define pr_fmt(fmt) fmt -- 2.10.2 ^ permalink raw reply related [flat|nested] 9+ messages in thread
* [PATCH 2/2] compiler.h: fix C++ uninitialized const issue 2017-02-21 15:24 [PATCH 1/2] Correct function definition for C++ Joakim Tjernlund @ 2017-02-21 15:24 ` Joakim Tjernlund 2017-02-22 7:10 ` [PATCH 1/2] Correct function definition for C++ Greg KH 1 sibling, 0 replies; 9+ messages in thread From: Joakim Tjernlund @ 2017-02-21 15:24 UTC (permalink / raw) To: linux-kernel, stable; +Cc: Joakim Tjernlund C++ does not like the union { typeof(x) __val; char __c[1]; } __u construct for const types: error: uninitialized const member in 'union atomic_read(const atomic_t*)::<anonymous>' Address this by creating a C++ version of READ_ONCE where this union is initialized: union { void _u(){}; typeof(x) __val; char __c[1]; } __u={0} To please gcc 6.3.0 also add in a _u(){} as default ctor. This makes C++ happy enough to build. Signed-off-by: Joakim Tjernlund <joakim.tjernlund@infinera.com> --- include/linux/compiler.h | 12 ++++++++++++ 1 file changed, 12 insertions(+) diff --git a/include/linux/compiler.h b/include/linux/compiler.h index cf0fa5d..0a047fd 100644 --- a/include/linux/compiler.h +++ b/include/linux/compiler.h @@ -300,6 +300,7 @@ static __always_inline void __write_once_size(volatile void *p, void *res, int s * required ordering. */ +#ifndef __cplusplus #define __READ_ONCE(x, check) \ ({ \ union { typeof(x) __val; char __c[1]; } __u; \ @@ -309,6 +310,17 @@ static __always_inline void __write_once_size(volatile void *p, void *res, int s __read_once_size_nocheck(&(x), __u.__c, sizeof(x)); \ __u.__val; \ }) +#else +#define __READ_ONCE(x, check) \ +({ \ + union { void _u(){}; typeof(x) __val; char __c[1]; } __u={0}; \ + if (check) \ + __read_once_size(&(x), __u.__c, sizeof(x)); \ + else \ + __read_once_size_nocheck(&(x), __u.__c, sizeof(x)); \ + __u.__val; \ +}) +#endif #define READ_ONCE(x) __READ_ONCE(x, 1) /* -- 2.10.2 ^ permalink raw reply related [flat|nested] 9+ messages in thread
* Re: [PATCH 1/2] Correct function definition for C++ 2017-02-21 15:24 [PATCH 1/2] Correct function definition for C++ Joakim Tjernlund 2017-02-21 15:24 ` [PATCH 2/2] compiler.h: fix C++ uninitialized const issue Joakim Tjernlund @ 2017-02-22 7:10 ` Greg KH 2017-02-22 7:50 ` Joakim Tjernlund 1 sibling, 1 reply; 9+ messages in thread From: Greg KH @ 2017-02-22 7:10 UTC (permalink / raw) To: Joakim Tjernlund; +Cc: linux-kernel, stable On Tue, Feb 21, 2017 at 04:24:04PM +0100, Joakim Tjernlund wrote: > C++ does does not like the extra extern before asmlinkage, remove it. > > Signed-off-by: Joakim Tjernlund <joakim.tjernlund@infinera.com> > --- > include/linux/printk.h | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > diff --git a/include/linux/printk.h b/include/linux/printk.h > index 3472cc6..be823f5 100644 > --- a/include/linux/printk.h > +++ b/include/linux/printk.h Why are you building this file with a C++ compiler? Also, this is not the correct way to submit patches for inclusion in the stable kernel tree. Please read Documentation/stable_kernel_rules.txt for how to do this properly. thanks, greg k-h ^ permalink raw reply [flat|nested] 9+ messages in thread
* Re: [PATCH 1/2] Correct function definition for C++ 2017-02-22 7:10 ` [PATCH 1/2] Correct function definition for C++ Greg KH @ 2017-02-22 7:50 ` Joakim Tjernlund 2017-02-22 13:03 ` greg 2017-02-28 23:15 ` Thomas Backlund 0 siblings, 2 replies; 9+ messages in thread From: Joakim Tjernlund @ 2017-02-22 7:50 UTC (permalink / raw) To: greg; +Cc: linux-kernel, stable On Wed, 2017-02-22 at 08:10 +0100, Greg KH wrote: > On Tue, Feb 21, 2017 at 04:24:04PM +0100, Joakim Tjernlund wrote: > > C++ does does not like the extra extern before asmlinkage, remove it. > > > > Signed-off-by: Joakim Tjernlund <joakim.tjernlund@infinera.com> > > --- > > include/linux/printk.h | 4 ++-- > > 1 file changed, 2 insertions(+), 2 deletions(-) > > > > diff --git a/include/linux/printk.h b/include/linux/printk.h > > index 3472cc6..be823f5 100644 > > --- a/include/linux/printk.h > > +++ b/include/linux/printk.h > > > Why are you building this file with a C++ compiler? virtualbox uses C++ and includes various kernel headers and the build fails, virtualbox guest additions has not build for quite some time now and this is one of the problems. > > Also, this is not the correct way to submit patches for inclusion in the > stable kernel tree. Please read Documentation/stable_kernel_rules.txt > for how to do this properly. Sorry, I was in a hurry(lazy:) so I just included stable directly as I know it needs to be fixed in 4.9 as well. Jocke ^ permalink raw reply [flat|nested] 9+ messages in thread
* Re: [PATCH 1/2] Correct function definition for C++ 2017-02-22 7:50 ` Joakim Tjernlund @ 2017-02-22 13:03 ` greg 2017-02-22 14:00 ` Joakim Tjernlund 2017-02-28 23:15 ` Thomas Backlund 1 sibling, 1 reply; 9+ messages in thread From: greg @ 2017-02-22 13:03 UTC (permalink / raw) To: Joakim Tjernlund; +Cc: linux-kernel, stable On Wed, Feb 22, 2017 at 07:50:46AM +0000, Joakim Tjernlund wrote: > On Wed, 2017-02-22 at 08:10 +0100, Greg KH wrote: > > On Tue, Feb 21, 2017 at 04:24:04PM +0100, Joakim Tjernlund wrote: > > > C++ does does not like the extra extern before asmlinkage, remove it. > > > > > > Signed-off-by: Joakim Tjernlund <joakim.tjernlund@infinera.com> > > > --- > > > include/linux/printk.h | 4 ++-- > > > 1 file changed, 2 insertions(+), 2 deletions(-) > > > > > > diff --git a/include/linux/printk.h b/include/linux/printk.h > > > index 3472cc6..be823f5 100644 > > > --- a/include/linux/printk.h > > > +++ b/include/linux/printk.h > > > > > > Why are you building this file with a C++ compiler? > > virtualbox uses C++ and includes various kernel headers and the build > fails, virtualbox guest additions has not build for quite some time now and > this is one of the problems. Virtualbox is a horrid pile of crap. You can quote me on that. We don't care about out-of-tree drivers, the authors should work to get them merged properly if they do care. Kernel code should be C, not C++, and if you do want to use C++, then you are on your own, sorry. > > Also, this is not the correct way to submit patches for inclusion in the > > stable kernel tree. Please read Documentation/stable_kernel_rules.txt > > for how to do this properly. > > Sorry, I was in a hurry(lazy:) so I just included stable directly as > I know it needs to be fixed in 4.9 as well. But that's not how to get a patch into the stable tree :( sorry, greg k-h ^ permalink raw reply [flat|nested] 9+ messages in thread
* Re: [PATCH 1/2] Correct function definition for C++ 2017-02-22 13:03 ` greg @ 2017-02-22 14:00 ` Joakim Tjernlund 2017-02-22 14:22 ` greg 0 siblings, 1 reply; 9+ messages in thread From: Joakim Tjernlund @ 2017-02-22 14:00 UTC (permalink / raw) To: greg; +Cc: linux-kernel, stable On Wed, 2017-02-22 at 14:03 +0100, greg@kroah.com wrote: > On Wed, Feb 22, 2017 at 07:50:46AM +0000, Joakim Tjernlund wrote: > > On Wed, 2017-02-22 at 08:10 +0100, Greg KH wrote: > > > On Tue, Feb 21, 2017 at 04:24:04PM +0100, Joakim Tjernlund wrote: > > > > C++ does does not like the extra extern before asmlinkage, remove it. > > > > > > > > Signed-off-by: Joakim Tjernlund <joakim.tjernlund@infinera.com> > > > > --- > > > > include/linux/printk.h | 4 ++-- > > > > 1 file changed, 2 insertions(+), 2 deletions(-) > > > > > > > > diff --git a/include/linux/printk.h b/include/linux/printk.h > > > > index 3472cc6..be823f5 100644 > > > > --- a/include/linux/printk.h > > > > +++ b/include/linux/printk.h > > > > > > > > > Why are you building this file with a C++ compiler? > > > > virtualbox uses C++ and includes various kernel headers and the build > > fails, virtualbox guest additions has not build for quite some time now and > > this is one of the problems. > > Virtualbox is a horrid pile of crap. You can quote me on that. We > don't care about out-of-tree drivers, the authors should work to get > them merged properly if they do care. Sure, I believe you :) But in this case it is not the kernel modules that fails, it is their guest additions/xf86 video driver. Seem like that these need to include some kernel herders there too. > > Kernel code should be C, not C++, and if you do want to use C++, then > you are on your own, sorry. But there are already a lot of C++ adjustments!? Just grepping for __cplusplus shows plenty of hits and what is the point of asmlinkage then: #ifdef __cplusplus #define CPP_ASMLINKAGE extern "C" #else #define CPP_ASMLINKAGE #endif #ifndef asmlinkage #define asmlinkage CPP_ASMLINKAGE #endif I read all of this that C++ code should be able to at least include kernel headers without fatal errors. You don't agree? In that case all __cplusplus/asmlinkage should be removed? > > > > Also, this is not the correct way to submit patches for inclusion in the > > > stable kernel tree. Please read Documentation/stable_kernel_rules.txt > > > for how to do this properly. > > > > Sorry, I was in a hurry(lazy:) so I just included stable directly as > > I know it needs to be fixed in 4.9 as well. > > But that's not how to get a patch into the stable tree :( > > sorry, Right, my mistake. No need to be sorry, I got what I deserved :) Jocke > > greg k-h ^ permalink raw reply [flat|nested] 9+ messages in thread
* Re: [PATCH 1/2] Correct function definition for C++ 2017-02-22 14:00 ` Joakim Tjernlund @ 2017-02-22 14:22 ` greg 2017-02-22 16:25 ` Joakim Tjernlund 0 siblings, 1 reply; 9+ messages in thread From: greg @ 2017-02-22 14:22 UTC (permalink / raw) To: Joakim Tjernlund; +Cc: linux-kernel, stable On Wed, Feb 22, 2017 at 02:00:53PM +0000, Joakim Tjernlund wrote: > On Wed, 2017-02-22 at 14:03 +0100, greg@kroah.com wrote: > > On Wed, Feb 22, 2017 at 07:50:46AM +0000, Joakim Tjernlund wrote: > > > On Wed, 2017-02-22 at 08:10 +0100, Greg KH wrote: > > > > On Tue, Feb 21, 2017 at 04:24:04PM +0100, Joakim Tjernlund wrote: > > > > > C++ does does not like the extra extern before asmlinkage, remove it. > > > > > > > > > > Signed-off-by: Joakim Tjernlund <joakim.tjernlund@infinera.com> > > > > > --- > > > > > include/linux/printk.h | 4 ++-- > > > > > 1 file changed, 2 insertions(+), 2 deletions(-) > > > > > > > > > > diff --git a/include/linux/printk.h b/include/linux/printk.h > > > > > index 3472cc6..be823f5 100644 > > > > > --- a/include/linux/printk.h > > > > > +++ b/include/linux/printk.h > > > > > > > > > > > > Why are you building this file with a C++ compiler? > > > > > > virtualbox uses C++ and includes various kernel headers and the build > > > fails, virtualbox guest additions has not build for quite some time now and > > > this is one of the problems. > > > > Virtualbox is a horrid pile of crap. You can quote me on that. We > > don't care about out-of-tree drivers, the authors should work to get > > them merged properly if they do care. > > Sure, I believe you :) > > But in this case it is not the kernel modules that fails, it is their > guest additions/xf86 video driver. Seem like that these need to include some > kernel herders there too. Seems like their build system is broken, it should not be including non uapi header files at all. > > Kernel code should be C, not C++, and if you do want to use C++, then > > you are on your own, sorry. > > But there are already a lot of C++ adjustments!? Just grepping for __cplusplus shows > plenty of hits and what is the point of asmlinkage then: > #ifdef __cplusplus > #define CPP_ASMLINKAGE extern "C" > #else > #define CPP_ASMLINKAGE > #endif > > #ifndef asmlinkage > #define asmlinkage CPP_ASMLINKAGE > #endif The usages in include/uapi/ make a bit of sense, but not much. Everything outside of there makes no sense at all (really just some drm and one scsi file.) They should be removed. > I read all of this that C++ code should be able to at least include kernel headers > without fatal errors. For uapi stuff, yes. But that's not what you are doing here. You are trying to build kernel code with a c++ compiler. That's not going to work. How is a C++ compiler supposed to parse the following line in device.h struct class; (one of my most proud moments...) thanks, greg k-h ^ permalink raw reply [flat|nested] 9+ messages in thread
* Re: [PATCH 1/2] Correct function definition for C++ 2017-02-22 14:22 ` greg @ 2017-02-22 16:25 ` Joakim Tjernlund 0 siblings, 0 replies; 9+ messages in thread From: Joakim Tjernlund @ 2017-02-22 16:25 UTC (permalink / raw) To: greg; +Cc: linux-kernel, stable On Wed, 2017-02-22 at 15:22 +0100, greg@kroah.com wrote: > On Wed, Feb 22, 2017 at 02:00:53PM +0000, Joakim Tjernlund wrote: > > On Wed, 2017-02-22 at 14:03 +0100, greg@kroah.com wrote: > > > On Wed, Feb 22, 2017 at 07:50:46AM +0000, Joakim Tjernlund wrote: > > > > On Wed, 2017-02-22 at 08:10 +0100, Greg KH wrote: > > > > > On Tue, Feb 21, 2017 at 04:24:04PM +0100, Joakim Tjernlund wrote: > > > > > > C++ does does not like the extra extern before asmlinkage, remove it. > > > > > > > > > > > > Signed-off-by: Joakim Tjernlund <joakim.tjernlund@infinera.com> > > > > > > --- > > > > > > include/linux/printk.h | 4 ++-- > > > > > > 1 file changed, 2 insertions(+), 2 deletions(-) > > > > > > > > > > > > diff --git a/include/linux/printk.h b/include/linux/printk.h > > > > > > index 3472cc6..be823f5 100644 > > > > > > --- a/include/linux/printk.h > > > > > > +++ b/include/linux/printk.h > > > > > > > > > > > > > > > Why are you building this file with a C++ compiler? > > > > > > > > virtualbox uses C++ and includes various kernel headers and the build > > > > fails, virtualbox guest additions has not build for quite some time now and > > > > this is one of the problems. > > > > > > Virtualbox is a horrid pile of crap. You can quote me on that. We > > > don't care about out-of-tree drivers, the authors should work to get > > > them merged properly if they do care. > > > > Sure, I believe you :) > > > > But in this case it is not the kernel modules that fails, it is their > > guest additions/xf86 video driver. Seem like that these need to include some > > kernel herders there too. > > Seems like their build system is broken, it should not be including non > uapi header files at all. > > > > Kernel code should be C, not C++, and if you do want to use C++, then > > > you are on your own, sorry. > > > > But there are already a lot of C++ adjustments!? Just grepping for __cplusplus shows > > plenty of hits and what is the point of asmlinkage then: > > #ifdef __cplusplus > > #define CPP_ASMLINKAGE extern "C" > > #else > > #define CPP_ASMLINKAGE > > #endif > > > > #ifndef asmlinkage > > #define asmlinkage CPP_ASMLINKAGE > > #endif > > The usages in include/uapi/ make a bit of sense, but not much. > Everything outside of there makes no sense at all (really just some drm > and one scsi file.) They should be removed. > > > I read all of this that C++ code should be able to at least include kernel headers > > without fatal errors. > > For uapi stuff, yes. But that's not what you are doing here. You are > trying to build kernel code with a c++ compiler. That's not going to > work. Right, I looked into guest-addition and it builds a few kernel modules too and include linux/string.h and that pulls in the offending code. Anyhow, the code in printk.h is "wrong" to add an extra extern so that change should not be a big deal as is, C++ or not. > > How is a C++ compiler supposed to parse the following line in device.h > struct class; > (one of my most proud moments...) :) ^ permalink raw reply [flat|nested] 9+ messages in thread
* Re: [PATCH 1/2] Correct function definition for C++ 2017-02-22 7:50 ` Joakim Tjernlund 2017-02-22 13:03 ` greg @ 2017-02-28 23:15 ` Thomas Backlund 1 sibling, 0 replies; 9+ messages in thread From: Thomas Backlund @ 2017-02-28 23:15 UTC (permalink / raw) To: Joakim Tjernlund; +Cc: linux-kernel, stable Den 22.02.2017 kl. 09:50, skrev Joakim Tjernlund: > On Wed, 2017-02-22 at 08:10 +0100, Greg KH wrote: >> On Tue, Feb 21, 2017 at 04:24:04PM +0100, Joakim Tjernlund wrote: >>> C++ does does not like the extra extern before asmlinkage, remove it. >>> >>> Signed-off-by: Joakim Tjernlund <joakim.tjernlund@infinera.com> >>> --- >>> include/linux/printk.h | 4 ++-- >>> 1 file changed, 2 insertions(+), 2 deletions(-) >>> >>> diff --git a/include/linux/printk.h b/include/linux/printk.h >>> index 3472cc6..be823f5 100644 >>> --- a/include/linux/printk.h >>> +++ b/include/linux/printk.h >> >> >> Why are you building this file with a C++ compiler? > > virtualbox uses C++ and includes various kernel headers and the build > fails, virtualbox guest additions has not build for quite some time now and > this is one of the problems. You need this fix for virtualbox: https://www.virtualbox.org/changeset/65874/vbox/trunk/configure -- Thomas ^ permalink raw reply [flat|nested] 9+ messages in thread
end of thread, other threads:[~2017-03-01 0:53 UTC | newest] Thread overview: 9+ messages (download: mbox.gz / follow: Atom feed) -- links below jump to the message on this page -- 2017-02-21 15:24 [PATCH 1/2] Correct function definition for C++ Joakim Tjernlund 2017-02-21 15:24 ` [PATCH 2/2] compiler.h: fix C++ uninitialized const issue Joakim Tjernlund 2017-02-22 7:10 ` [PATCH 1/2] Correct function definition for C++ Greg KH 2017-02-22 7:50 ` Joakim Tjernlund 2017-02-22 13:03 ` greg 2017-02-22 14:00 ` Joakim Tjernlund 2017-02-22 14:22 ` greg 2017-02-22 16:25 ` Joakim Tjernlund 2017-02-28 23:15 ` Thomas Backlund
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