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From:   Arnd Bergmann <arnd@arndb.de>
To:     Boris Ostrovsky <boris.ostrovsky@oracle.com>,
        Juergen Gross <jgross@suse.com>
Cc:     Arnd Bergmann <arnd@arndb.de>,
        Stefano Stabellini <sstabellini@kernel.org>,
        xen-devel@lists.xenproject.org, linux-kernel@vger.kernel.org
Subject: [PATCH] [v3] xen: avoid link error on ARM
Date:   Mon, 22 Jul 2019 09:46:29 +0200
Message-Id: <20190722074705.2082153-1-arnd@arndb.de>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

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