Mailing List Archive

[PATCH] [v3] xen: avoid link error on ARM
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 that is always built in when Xen is enabled,
as suggested by Juergen Gross and Boris Ostrovsky.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
---
v2: rename mm.o to xen-builtin.o, make it unconditional
v3: move new code into xlate_mmu as suggested by Boris Ostrovsky.
sorry for the long delay since v2, I lost track of this.
---
drivers/xen/privcmd.c | 35 +++++------------------------------
drivers/xen/xlate_mmu.c | 32 ++++++++++++++++++++++++++++++++
include/xen/xen-ops.h | 3 +++
3 files changed, 40 insertions(+), 30 deletions(-)

diff --git a/drivers/xen/privcmd.c b/drivers/xen/privcmd.c
index 2f5ce7230a43..c6070e70dd73 100644
--- a/drivers/xen/privcmd.c
+++ b/drivers/xen/privcmd.c
@@ -724,25 +724,6 @@ 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, 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;
@@ -774,7 +755,8 @@ static long privcmd_ioctl_mmap_resource(struct file *file, void __user *udata)
goto out;
}

- if (xen_feature(XENFEAT_auto_translated_physmap)) {
+ if (IS_ENABLED(CONFIG_XEN_AUTO_XLATE) &&
+ xen_feature(XENFEAT_auto_translated_physmap)) {
unsigned int nr = DIV_ROUND_UP(kdata.num, XEN_PFN_PER_PAGE);
struct page **pages;
unsigned int i;
@@ -808,16 +790,9 @@ static long privcmd_ioctl_mmap_resource(struct file *file, void __user *udata)
if (rc)
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);
+ if (IS_ENABLED(CONFIG_XEN_AUTO_XLATE) &&
+ xen_feature(XENFEAT_auto_translated_physmap)) {
+ 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/xlate_mmu.c b/drivers/xen/xlate_mmu.c
index ba883a80b3c0..7b1077f0abcb 100644
--- a/drivers/xen/xlate_mmu.c
+++ b/drivers/xen/xlate_mmu.c
@@ -262,3 +262,35 @@ int __init xen_xlate_map_ballooned_pages(xen_pfn_t **gfns, void **virt,
return 0;
}
EXPORT_SYMBOL_GPL(xen_xlate_map_ballooned_pages);
+
+struct remap_pfn {
+ struct mm_struct *mm;
+ struct page **pages;
+ pgprot_t prot;
+ unsigned long i;
+};
+
+static int remap_pfn_fn(pte_t *ptep, 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
--
2.20.0


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Re: [PATCH] [v3] xen: avoid link error on ARM [ In reply to ]
On Mon, 22 Jul 2019, 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 that is always built in when Xen is enabled,
> as suggested by Juergen Gross and Boris Ostrovsky.
>
> Signed-off-by: Arnd Bergmann <arnd@arndb.de>
> ---
> v2: rename mm.o to xen-builtin.o, make it unconditional
> v3: move new code into xlate_mmu as suggested by Boris Ostrovsky.
> sorry for the long delay since v2, I lost track of this.
> ---
> drivers/xen/privcmd.c | 35 +++++------------------------------
> drivers/xen/xlate_mmu.c | 32 ++++++++++++++++++++++++++++++++
> include/xen/xen-ops.h | 3 +++
> 3 files changed, 40 insertions(+), 30 deletions(-)
>
> diff --git a/drivers/xen/privcmd.c b/drivers/xen/privcmd.c
> index 2f5ce7230a43..c6070e70dd73 100644
> --- a/drivers/xen/privcmd.c
> +++ b/drivers/xen/privcmd.c
> @@ -724,25 +724,6 @@ 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, 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;
> @@ -774,7 +755,8 @@ static long privcmd_ioctl_mmap_resource(struct file *file, void __user *udata)
> goto out;
> }
>
> - if (xen_feature(XENFEAT_auto_translated_physmap)) {
> + if (IS_ENABLED(CONFIG_XEN_AUTO_XLATE) &&
> + xen_feature(XENFEAT_auto_translated_physmap)) {

The patch looks good. I tested it and works as intended. Instead of
adding the additional IS_ENABLED check, I would have gone with providing
an empty implementation of xen_remap_vma_range as a static inline
function, if CONFIG_XEN_AUTO_XLATE is not enabled.

Either way:

Reviewed-by: Stefano Stabellini <sstabellini@kernel.org>


> unsigned int nr = DIV_ROUND_UP(kdata.num, XEN_PFN_PER_PAGE);
> struct page **pages;
> unsigned int i;
> @@ -808,16 +790,9 @@ static long privcmd_ioctl_mmap_resource(struct file *file, void __user *udata)
> if (rc)
> 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);
> + if (IS_ENABLED(CONFIG_XEN_AUTO_XLATE) &&
> + xen_feature(XENFEAT_auto_translated_physmap)) {
> + 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/xlate_mmu.c b/drivers/xen/xlate_mmu.c
> index ba883a80b3c0..7b1077f0abcb 100644
> --- a/drivers/xen/xlate_mmu.c
> +++ b/drivers/xen/xlate_mmu.c
> @@ -262,3 +262,35 @@ int __init xen_xlate_map_ballooned_pages(xen_pfn_t **gfns, void **virt,
> return 0;
> }
> EXPORT_SYMBOL_GPL(xen_xlate_map_ballooned_pages);
> +
> +struct remap_pfn {
> + struct mm_struct *mm;
> + struct page **pages;
> + pgprot_t prot;
> + unsigned long i;
> +};
> +
> +static int remap_pfn_fn(pte_t *ptep, 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
> --
> 2.20.0
>

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Re: [PATCH] [v3] xen: avoid link error on ARM [ In reply to ]
On 22.07.19 09:46, 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 that is always built in when Xen is enabled,
> as suggested by Juergen Gross and Boris Ostrovsky.
>
> Signed-off-by: Arnd Bergmann <arnd@arndb.de>

Pushed to xen/tip.git for-linus-5.3a


Juergen

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