Re: [PATCH 11/12] avoid using predefined PAGE_SIZE

[Szabolcs Nagy <szabolcs.nagy@arm.com>]

On 17/07/15 17:02, Andre Przywara wrote:
> The musl-libc comes with a predefined PAGE_SIZE macro, which may be
> wrong on systems which support multiple smallest page sizes.
> Make sure we use our own (runtime evaluated) definition of PAGE_SIZE.
>

musl only provides PAGE_SIZE on archs where it is
constant, if not, that's a musl bug and should be
fixed there (this is a posix requirement).

the ifdef does not help around this: musl sysconf
will return the same value as you get from the
header (it would be a conformance bug otherwise).

use

#include <limits.h>
#ifndef PAGE_SIZE
#define PAGE_SIZE sysconf(_SC_PAGE_SIZE)
#endif

> Signed-off-by: Andre Przywara <andre.przywara@arm.com>
> ---
>  include/kvm/kvm.h | 4 ++++
>  1 file changed, 4 insertions(+)
>
> diff --git a/include/kvm/kvm.h b/include/kvm/kvm.h
> index 9818046..8b12cd6 100644
> --- a/include/kvm/kvm.h
> +++ b/include/kvm/kvm.h
> @@ -19,6 +19,10 @@
>  #define HOME_DIR             getenv("HOME")
>  #define KVM_BINARY_NAME              "lkvm"
>
> +/* Let's determine the actual page size at runtime. */
> +#ifdef PAGE_SIZE
> +#undef PAGE_SIZE
> +#endif
>  #define PAGE_SIZE (sysconf(_SC_PAGE_SIZE))
>
>  #define DEFINE_KVM_EXT(ext)          \
>


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