[v2] xen: avoid link error on ARM

Message ID 20190305133057.3998926-1-arnd@arndb.de
State New
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  • [v2] xen: avoid link error on ARM
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Commit Message

Arnd Bergmann March 5, 2019, 1:30 p.m.
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@arndb.de>

---
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

-- 
2.20.0

Comments

Jürgen Groß March 5, 2019, 1:35 p.m. | #1
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@arndb.de>

> ---

> 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@citrix.com>

> + */

> +#include <linux/mm.h>

> +#include <linux/export.h>


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


Juergen
Boris Ostrovsky March 5, 2019, 1:43 p.m. | #2
On 3/5/19 8:30 AM, Arnd Bergmann wrote:
>  

> 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);


I wonder whether drivers/xen/xlate_mmu.c might be a good place for these
routines.

-boris
Jürgen Groß March 5, 2019, 2:57 p.m. | #3
On 05/03/2019 14:43, Boris Ostrovsky wrote:
> On 3/5/19 8:30 AM, Arnd Bergmann wrote:

>>  

>> 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);

> 

> I wonder whether drivers/xen/xlate_mmu.c might be a good place for these

> routines.


Hmm, probably. This would require a stub in the header to avoid
problems in case of CONFIG_XEN_AUTO_XLATE not defined, though
(the #ifdef is already there).

I think this is the cleanest solution.


Juergen
Arnd Bergmann March 5, 2019, 4:49 p.m. | #4
On Tue, Mar 5, 2019 at 3:57 PM Juergen Gross <jgross@suse.com> wrote:
> On 05/03/2019 14:43, Boris Ostrovsky wrote:

> > On 3/5/19 8:30 AM, Arnd Bergmann wrote:


> >> @@ -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);

> >

> > I wonder whether drivers/xen/xlate_mmu.c might be a good place for these

> > routines.

>

> Hmm, probably. This would require a stub in the header to avoid

> problems in case of CONFIG_XEN_AUTO_XLATE not defined, though

> (the #ifdef is already there).

>

> I think this is the cleanest solution.


Putting it into xlate_mmu.c was my first attempt, but I was not sure how to
solve the dependency on CONFIG_XEN_AUTO_XLATE. So
xen_feature(XENFEAT_auto_translated_physmap)) would be guaranteed
to return false if CONFIG_XEN_AUTO_XLATE is disabled?

       Arnd
Jürgen Groß March 5, 2019, 4:56 p.m. | #5
On 05/03/2019 17:49, Arnd Bergmann wrote:
> On Tue, Mar 5, 2019 at 3:57 PM Juergen Gross <jgross@suse.com> wrote:

>> On 05/03/2019 14:43, Boris Ostrovsky wrote:

>>> On 3/5/19 8:30 AM, Arnd Bergmann wrote:

> 

>>>> @@ -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);

>>>

>>> I wonder whether drivers/xen/xlate_mmu.c might be a good place for these

>>> routines.

>>

>> Hmm, probably. This would require a stub in the header to avoid

>> problems in case of CONFIG_XEN_AUTO_XLATE not defined, though

>> (the #ifdef is already there).

>>

>> I think this is the cleanest solution.

> 

> Putting it into xlate_mmu.c was my first attempt, but I was not sure how to

> solve the dependency on CONFIG_XEN_AUTO_XLATE. So

> xen_feature(XENFEAT_auto_translated_physmap)) would be guaranteed

> to return false if CONFIG_XEN_AUTO_XLATE is disabled?


Yes.


Juergen

Patch

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@citrix.com>
+ */
+#include <linux/mm.h>
+#include <linux/export.h>
+
+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;
+}
+
+/* Used by the privcmd module, but has to be built-in on ARM */
+int xen_remap_vma_range(struct vm_area_struct *vma, unsigned long addr, unsigned long len)
+{
+	struct remap_pfn r = {
+		.mm = vma->vm_mm,
+		.pages = vma->vm_private_data,
+		.prot = vma->vm_page_prot,
+	};
+
+	return apply_to_page_range(vma->vm_mm, addr, len, remap_pfn_fn, &r);
+}
+EXPORT_SYMBOL_GPL(xen_remap_vma_range);
diff --git a/include/xen/xen-ops.h b/include/xen/xen-ops.h
index 4969817124a8..98b30c1613b2 100644
--- a/include/xen/xen-ops.h
+++ b/include/xen/xen-ops.h
@@ -109,6 +109,9 @@  static inline int xen_xlate_unmap_gfn_range(struct vm_area_struct *vma,
 }
 #endif
 
+int xen_remap_vma_range(struct vm_area_struct *vma, unsigned long addr,
+			unsigned long len);
+
 /*
  * xen_remap_domain_gfn_array() - map an array of foreign frames by gfn
  * @vma:     VMA to map the pages into