Function alloc_sv_fxrng_generation

freebsd/kern/kern_sharedpage.c:281–301

}

static void
alloc_sv_fxrng_generation(void)
{
	int base;

	/*
	 * Allocate a full cache line for the fxrng root generation (64-bit
	 * counter, or truncated 32-bit counter on ILP32 userspace).  It is
	 * important that the line is not shared with frequently dirtied data,
	 * and the shared page allocator lacks a __read_mostly mechanism.
	 * However, PAGE_SIZE is typically large relative to the amount of
	 * stuff we've got in it so far, so maybe the possible waste isn't an
	 * issue.
	 */
	base = shared_page_alloc(CACHE_LINE_SIZE, CACHE_LINE_SIZE);
	KASSERT(base != -1, ("%s: base allocation failed", __func__));
	fxrng_shpage_mapping = (void *)(shared_page_mapping + base);
	*fxrng_shpage_mapping = (struct vdso_fxrng_generation) {
		.fx_vdso_version = VDSO_FXRNG_VER_CURR,
	};
}
#endif /* RANDOM_FENESTRASX */

void