Re: [PATCH] [v2] xen: avoid link error on ARM

[Juergen Gross]

On 05/03/2019 14:30, Arnd Bergmann wrote:
> Building the privcmd code as a loadable module on ARM, we get
> a link error due to the private cache management functions:
> 
> ERROR: "__sync_icache_dcache" [drivers/xen/xen-privcmd.ko] undefined!
> 
> Move the code into a new file that is always built in when Xen
> is enabled, as suggested by Juergen Gross. Additional code will
> be moved into this file later.
> 
> Signed-off-by: Arnd Bergmann <arnd@xxxxxxxx>
> ---
> v2: rename mm.o to xen-builtin.o, make it unconditional
> ---
>  drivers/xen/Makefile      |  1 +
>  drivers/xen/privcmd.c     | 30 +---------------------------
>  drivers/xen/xen-builtin.c | 41 +++++++++++++++++++++++++++++++++++++++
>  include/xen/xen-ops.h     |  3 +++
>  4 files changed, 46 insertions(+), 29 deletions(-)
>  create mode 100644 drivers/xen/xen-builtin.c
> 
> diff --git a/drivers/xen/Makefile b/drivers/xen/Makefile
> index ad3844d9f876..c3cbfcf30d38 100644
> --- a/drivers/xen/Makefile
> +++ b/drivers/xen/Makefile
> @@ -2,6 +2,7 @@
>  obj-$(CONFIG_HOTPLUG_CPU)		+= cpu_hotplug.o
>  obj-y	+= grant-table.o features.o balloon.o manage.o preempt.o time.o
>  obj-y	+= mem-reservation.o
> +obj-y	+= xen-builtin.o
>  obj-y	+= events/
>  obj-y	+= xenbus/
>  
> diff --git a/drivers/xen/privcmd.c b/drivers/xen/privcmd.c
> index b24ddac1604b..290b6aca7e1d 100644
> --- a/drivers/xen/privcmd.c
> +++ b/drivers/xen/privcmd.c
> @@ -723,26 +723,6 @@ static long privcmd_ioctl_restrict(struct file *file, void __user *udata)
>  	return 0;
>  }
>  
> -struct remap_pfn {
> -	struct mm_struct *mm;
> -	struct page **pages;
> -	pgprot_t prot;
> -	unsigned long i;
> -};
> -
> -static int remap_pfn_fn(pte_t *ptep, pgtable_t token, unsigned long addr,
> -			void *data)
> -{
> -	struct remap_pfn *r = data;
> -	struct page *page = r->pages[r->i];
> -	pte_t pte = pte_mkspecial(pfn_pte(page_to_pfn(page), r->prot));
> -
> -	set_pte_at(r->mm, addr, ptep, pte);
> -	r->i++;
> -
> -	return 0;
> -}
> -
>  static long privcmd_ioctl_mmap_resource(struct file *file, void __user *udata)
>  {
>  	struct privcmd_data *data = file->private_data;
> @@ -809,15 +789,7 @@ static long privcmd_ioctl_mmap_resource(struct file *file, void __user *udata)
>  		goto out;
>  
>  	if (xen_feature(XENFEAT_auto_translated_physmap)) {
> -		struct remap_pfn r = {
> -			.mm = vma->vm_mm,
> -			.pages = vma->vm_private_data,
> -			.prot = vma->vm_page_prot,
> -		};
> -
> -		rc = apply_to_page_range(r.mm, kdata.addr,
> -					 kdata.num << PAGE_SHIFT,
> -					 remap_pfn_fn, &r);
> +		rc = xen_remap_vma_range(vma, kdata.addr, kdata.num << PAGE_SHIFT);
>  	} else {
>  		unsigned int domid =
>  			(xdata.flags & XENMEM_rsrc_acq_caller_owned) ?
> diff --git a/drivers/xen/xen-builtin.c b/drivers/xen/xen-builtin.c
> new file mode 100644
> index 000000000000..8ad0d4900588
> --- /dev/null
> +++ b/drivers/xen/xen-builtin.c
> @@ -0,0 +1,41 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Architecture independent helper functions for memory management
> + *
> + * Written by Paul Durrant <paul.durrant@xxxxxxxxxx>
> + */
> +#include <linux/mm.h>
> +#include <linux/export.h>

Shouldn't you #include xen/xen-ops.h here as well?


Juergen