On 13.03.2024 18:27, Andrew Cooper wrote:
> * Rename __attribute_pure__ to just __pure before it gains users.
> * Identify the areas of xen/bitops.h which are a mess.
> * Create common/bitops.c for compile and runtime testing. This provides a
> statement of the ABI, and a confirmation that arch-specific implementations
> behave as expected.
If this is the sole purpose of the new file, then ...
> --- a/xen/common/Makefile
> +++ b/xen/common/Makefile
> @@ -1,5 +1,6 @@
> obj-$(CONFIG_ARGO) += argo.o
> obj-y += bitmap.o
> +obj-y += bitops.o
obj-bin-y += bitops.init.o
please.
> --- /dev/null
> +++ b/xen/common/bitops.c
> @@ -0,0 +1,41 @@
> +#include <xen/bitops.h>
> +#include <xen/bug.h>
> +#include <xen/init.h>
> +
> +/* Hide a value from the optimiser. */
> +#define HIDE(x) ({ typeof(x) _x = x; asm volatile ( "" : "+r" (_x) ); _x; })
Irrespective of the question of leading underscores, x wants parenthesizing
here.
> +/*
> + * Check that fn(val) can be calcuated by the compiler, and that it gives the
> + * expected answer.
> + */
> +#define COMPILE_CHECK(fn, val, res) \
> + do { \
> + if ( fn(val) != res ) \
> + asm (".error \"Compile time check '" STR(fn(val) == res) "'
> failed\""); \
Nit: Blanks missing immediately inside the outermost pair of parentheses. (As
per your own reply it's unclear whether this would actually survive.)
> --- a/xen/include/xen/compiler.h
> +++ b/xen/include/xen/compiler.h
> @@ -85,7 +85,8 @@
> #define inline inline __init
> #endif
>
> -#define __attribute_pure__ __attribute__((__pure__))
> +#define __pure __attribute__((__pure__))
I'd say either there be just a single padding blank or enough to align the
rhs with ...
> #define __attribute_const__ __attribute__((__const__))
> #define __transparent__ __attribute__((__transparent_union__))
... these.
Jan
