[PATCH v2 09/40] xen/arm: decouple copy_from_paddr with FIXMAP

[Penny Zheng <Penny.Zheng@xxxxxxx>]

From: Wei Chen <wei.chen@xxxxxxx>

copy_from_paddr will map a page to Xen's FIXMAP_MISC area for
temporary access. But for those systems do not support VMSA,
they can not implement set_fixmap/clear_fixmap, that means they
can't always use the same virtual address for source address.

In this case, we introduce to helpers to decouple copy_from_paddr
with set_fixmap/clear_fixmap. map_page_to_xen_misc can always
return the same virtual address as before for VMSA systems. It
also can return different address for non-VMSA systems.

Signed-off-by: Wei Chen <wei.chen@xxxxxxx>
---
v1 -> v2:
1. New patch
---
 xen/arch/arm/include/asm/setup.h |  4 ++++
 xen/arch/arm/kernel.c            | 13 +++++++------
 xen/arch/arm/mm.c                | 12 ++++++++++++
 3 files changed, 23 insertions(+), 6 deletions(-)

diff --git a/xen/arch/arm/include/asm/setup.h b/xen/arch/arm/include/asm/setup.h
index a926f30a2b..4f39a1aa0a 100644
--- a/xen/arch/arm/include/asm/setup.h
+++ b/xen/arch/arm/include/asm/setup.h
@@ -119,6 +119,10 @@ extern struct bootinfo bootinfo;
 
 extern domid_t max_init_domid;
 
+/* Map a page to misc area */
+void *map_page_to_xen_misc(mfn_t mfn, unsigned int attributes);
+/* Unmap the page from misc area */
+void unmap_page_from_xen_misc(void);
 void copy_from_paddr(void *dst, paddr_t paddr, unsigned long len);
 
 size_t estimate_efi_size(unsigned int mem_nr_banks);
diff --git a/xen/arch/arm/kernel.c b/xen/arch/arm/kernel.c
index 23b840ea9e..0475d8fae7 100644
--- a/xen/arch/arm/kernel.c
+++ b/xen/arch/arm/kernel.c
@@ -49,18 +49,19 @@ struct minimal_dtb_header {
  */
 void __init copy_from_paddr(void *dst, paddr_t paddr, unsigned long len)
 {
-    void *src = (void *)FIXMAP_ADDR(FIXMAP_MISC);
-
-    while (len) {
+    while ( len )
+    {
+        void *src;
         unsigned long l, s;
 
-        s = paddr & (PAGE_SIZE-1);
+        s = paddr & (PAGE_SIZE - 1);
         l = min(PAGE_SIZE - s, len);
 
-        set_fixmap(FIXMAP_MISC, maddr_to_mfn(paddr), PAGE_HYPERVISOR_WC);
+        src = map_page_to_xen_misc(maddr_to_mfn(paddr), PAGE_HYPERVISOR_WC);
+        ASSERT(src != NULL);
         memcpy(dst, src + s, l);
         clean_dcache_va_range(dst, l);
-        clear_fixmap(FIXMAP_MISC);
+        unmap_page_from_xen_misc();
 
         paddr += l;
         dst += l;
diff --git a/xen/arch/arm/mm.c b/xen/arch/arm/mm.c
index 0fc6f2992d..8f15814c5e 100644
--- a/xen/arch/arm/mm.c
+++ b/xen/arch/arm/mm.c
@@ -355,6 +355,18 @@ void clear_fixmap(unsigned int map)
     BUG_ON(res != 0);
 }
 
+void *map_page_to_xen_misc(mfn_t mfn, unsigned int attributes)
+{
+    set_fixmap(FIXMAP_MISC, mfn, attributes);
+
+    return fix_to_virt(FIXMAP_MISC);
+}
+
+void unmap_page_from_xen_misc(void)
+{
+    clear_fixmap(FIXMAP_MISC);
+}
+
 void flush_page_to_ram(unsigned long mfn, bool sync_icache)
 {
     void *v = map_domain_page(_mfn(mfn));
-- 
2.25.1