[PATCH 2/2] xen/device-tree: move discard_initial_modules() to common code

[Oleksii Kurochko <oleksii.kurochko@xxxxxxxxx>]

Everything discard_initial_modules() touches is already common code:
bootinfo.modules, using_static_heap and fw_unreserved_regions(). Move it
out of Arm into common/device-tree/bootinfo.c, next to the boot allocator
handling of the same memory, and declare it in xen/bootinfo.h, so that
other device-tree based architectures can reuse it instead of growing a
copy of their own.

The arch-specific remove_early_mappings() is not moved along with it:
how the early FDT mapping is torn down is up to the architecture. As the
DTB is one of the boot modules being released, the mapping has to go once
they are discarded, so call it from start_xen() right after
discard_initial_modules(), which keeps the common function free of any
arch dependency.

While moving it, use unsigned int for the loop counter and replace the
"goto out" by a plain return, as there is nothing left to do at the label.

No functional change.

Signed-off-by: Oleksii Kurochko <oleksii.kurochko@xxxxxxxxx>
---
 xen/arch/arm/include/asm/setup.h  |  2 --
 xen/arch/arm/setup.c              | 35 ++-----------------------------
 xen/common/device-tree/bootinfo.c | 30 ++++++++++++++++++++++++++
 xen/include/xen/bootinfo.h        |  8 +++++++
 4 files changed, 40 insertions(+), 35 deletions(-)

diff --git a/xen/arch/arm/include/asm/setup.h b/xen/arch/arm/include/asm/setup.h
index c491c567298f..02fdf2b56c9c 100644
--- a/xen/arch/arm/include/asm/setup.h
+++ b/xen/arch/arm/include/asm/setup.h
@@ -40,8 +40,6 @@ int acpi_make_efi_nodes(void *fdt, struct membank tbl_add[]);
 
 void create_dom0(void);
 
-void discard_initial_modules(void);
-
 void init_pdx(void);
 void setup_mm(void);
 
diff --git a/xen/arch/arm/setup.c b/xen/arch/arm/setup.c
index 16f899dff57b..a65c3d2a655e 100644
--- a/xen/arch/arm/setup.c
+++ b/xen/arch/arm/setup.c
@@ -210,39 +210,6 @@ static void __init processor_id(void)
     processor_setup();
 }
 
-void __init discard_initial_modules(void)
-{
-    struct boot_modules *mi = &bootinfo.modules;
-    int i;
-
-    /*
-     * When using static heap feature, don't give boot_modules memory back to
-     * the heap allocator
-     */
-    if ( using_static_heap )
-        goto out;
-
-    for ( i = 0; i < mi->nr_mods; i++ )
-    {
-        paddr_t s = mi->module[i].start;
-        paddr_t e = s + PAGE_ALIGN(mi->module[i].size);
-
-        if ( mi->module[i].kind == BOOTMOD_XEN )
-            continue;
-
-        if ( !mfn_valid(maddr_to_mfn(s)) ||
-             !mfn_valid(maddr_to_mfn(e)) )
-            continue;
-
-        fw_unreserved_regions(s, e, init_domheap_pages, 0);
-    }
-
-    mi->nr_mods = 0;
-
- out:
-    remove_early_mappings();
-}
-
 /* Relocate the FDT in Xen heap */
 static void __init relocate_fdt(const void **dtb_vaddr, size_t dtb_size)
 {
@@ -509,6 +476,8 @@ void asmlinkage __init noreturn start_xen(unsigned long 
fdt_paddr)
      */
     discard_initial_modules();
 
+    remove_early_mappings();
+
     heap_init_late();
 
     init_constructors();
diff --git a/xen/common/device-tree/bootinfo.c 
b/xen/common/device-tree/bootinfo.c
index c637c45ad594..6772bf2df002 100644
--- a/xen/common/device-tree/bootinfo.c
+++ b/xen/common/device-tree/bootinfo.c
@@ -471,6 +471,36 @@ void __init populate_boot_allocator(void)
     }
 }
 
+void __init discard_initial_modules(void)
+{
+    struct boot_modules *mi = &bootinfo.modules;
+    unsigned int i;
+
+    /*
+     * When using static heap feature, don't give boot_modules memory back to
+     * the heap allocator
+     */
+    if ( using_static_heap )
+        return;
+
+    for ( i = 0; i < mi->nr_mods; i++ )
+    {
+        paddr_t s = mi->module[i].start;
+        paddr_t e = s + PAGE_ALIGN(mi->module[i].size);
+
+        if ( mi->module[i].kind == BOOTMOD_XEN )
+            continue;
+
+        if ( !mfn_valid(maddr_to_mfn(s)) ||
+             !mfn_valid(maddr_to_mfn(e)) )
+            continue;
+
+        fw_unreserved_regions(s, e, init_domheap_pages, 0);
+    }
+
+    mi->nr_mods = 0;
+}
+
 /*
  * Local variables:
  * mode: C
diff --git a/xen/include/xen/bootinfo.h b/xen/include/xen/bootinfo.h
index dbf492c2e36e..60ef25f3cf83 100644
--- a/xen/include/xen/bootinfo.h
+++ b/xen/include/xen/bootinfo.h
@@ -214,4 +214,12 @@ void fw_unreserved_regions(paddr_t s, paddr_t e,
                            void (*cb)(paddr_t ps, paddr_t pe),
                            unsigned int first);
 
+/*
+ * Return the memory occupied by the boot modules to the heap allocator.
+ *
+ * It needs to be called **before** heap_init_late() so that the released
+ * modules are scrubbed (unless suppressed).
+ */
+void discard_initial_modules(void);
+
 #endif /* XEN_BOOTINFO_H */
-- 
2.55.0