| Message ID | 20200502160700.19573-4-julien@xen.org (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | Rework {read, write}_atomic() | expand |
On 02.05.2020 18:07, Julien Grall wrote: > From: Julien Grall <jgrall@amazon.com> > > At the moment, write_atomic() will happily write to a pointer to const. > While there are no use in Xen, it would be best to catch them at > compilation time. > > Signed-off-by: Julien Grall <jgrall@amazon.com> Acked-by: Jan Beulich <jbeulich@suse.com> albeit ... > --- a/xen/include/asm-x86/atomic.h > +++ b/xen/include/asm-x86/atomic.h > @@ -63,6 +63,8 @@ void __bad_atomic_size(void); > > #define write_atomic(p, x) ({ \ > typeof(*(p)) __x = (x); \ > + /* Check that the pointer is not const */ \ > + void *__maybe_unused p_ = &__x; \ ... along the lines of the similar case with guest handles I'd like to suggest for the comment to be more precise: It's not the pointer's const-ness you're after, but the pointed to object's. Maybe "Check that the pointer is not to a const type" or even just "Check that the pointer is not to const"? Jan
Hi Jan, On 04/05/2020 11:47, Jan Beulich wrote: > On 02.05.2020 18:07, Julien Grall wrote: >> From: Julien Grall <jgrall@amazon.com> >> >> At the moment, write_atomic() will happily write to a pointer to const. >> While there are no use in Xen, it would be best to catch them at >> compilation time. >> >> Signed-off-by: Julien Grall <jgrall@amazon.com> > > Acked-by: Jan Beulich <jbeulich@suse.com> > albeit ... > >> --- a/xen/include/asm-x86/atomic.h >> +++ b/xen/include/asm-x86/atomic.h >> @@ -63,6 +63,8 @@ void __bad_atomic_size(void); >> >> #define write_atomic(p, x) ({ \ >> typeof(*(p)) __x = (x); \ >> + /* Check that the pointer is not const */ \ >> + void *__maybe_unused p_ = &__x; \ > > ... along the lines of the similar case with guest handles I'd > like to suggest for the comment to be more precise: It's not > the pointer's const-ness you're after, but the pointed to > object's. Maybe "Check that the pointer is not to a const > type" or even just "Check that the pointer is not to const"? I am happy with "Check that the pointer is not to a const type". Cheers,
diff --git a/xen/include/asm-x86/atomic.h b/xen/include/asm-x86/atomic.h index 6b40f9c9f872..0a332b1fae18 100644 --- a/xen/include/asm-x86/atomic.h +++ b/xen/include/asm-x86/atomic.h @@ -63,6 +63,8 @@ void __bad_atomic_size(void); #define write_atomic(p, x) ({ \ typeof(*(p)) __x = (x); \ + /* Check that the pointer is not const */ \ + void *__maybe_unused p_ = &__x; \ unsigned long x_ = (unsigned long)__x; \ switch ( sizeof(*(p)) ) { \ case 1: write_u8_atomic((uint8_t *)(p), x_); break; \