[PATCH V4 05/10] xen/arm: static memory initialization

[Penny Zheng <penny.zheng@arm.com>]

This patch introduces static memory initialization, during system boot up.

The new function init_staticmem_pages is responsible for static memory
initialization.

Helper free_staticmem_pages is the equivalent of free_heap_pages, to free
nr_mfns pages of static memory.

This commit also introduces new CONFIG_STATIC_MEMORY to avoid bringing dead
codes in other archs.

Put asynchronous scrubbing for pages of static memory in TODO list.

Signed-off-by: Penny Zheng <penny.zheng@arm.com>
---
v4 change:
- move the option CONFIG_STATIC_MEMORY to common code, and with Arm
"select"ing it
- replace round_pg{down,up}() with PFN_DOWN()/PFN_UP()
---
 xen/arch/arm/Kconfig    |  1 +
 xen/arch/arm/setup.c    | 24 ++++++++++++++++++++++++
 xen/common/Kconfig      |  3 +++
 xen/common/page_alloc.c | 20 ++++++++++++++++++++
 xen/include/xen/mm.h    |  6 ++++++
 5 files changed, 54 insertions(+)

diff --git a/xen/arch/arm/Kconfig b/xen/arch/arm/Kconfig
index ecfa6822e4..cc7a943d27 100644
--- a/xen/arch/arm/Kconfig
+++ b/xen/arch/arm/Kconfig
@@ -15,6 +15,7 @@ config ARM
 	select HAS_PASSTHROUGH
 	select HAS_PDX
 	select IOMMU_FORCE_PT_SHARE
+	select STATIC_MEMORY
 
 config ARCH_DEFCONFIG
 	string
diff --git a/xen/arch/arm/setup.c b/xen/arch/arm/setup.c
index f569134317..369f6631ee 100644
--- a/xen/arch/arm/setup.c
+++ b/xen/arch/arm/setup.c
@@ -622,6 +622,26 @@ static void __init init_pdx(void)
     }
 }
 
+/* Static memory initialization */
+static void __init init_staticmem_pages(void)
+{
+    unsigned int bank;
+
+    /* TODO: Considering NUMA-support scenario. */
+    for ( bank = 0 ; bank < bootinfo.static_mem.nr_banks; bank++ )
+    {
+        unsigned long bank_start = PFN_UP(bootinfo.static_mem.bank[bank].start);
+        unsigned long bank_size = PFN_DOWN(bootinfo.static_mem.bank[bank].size);
+        unsigned long bank_end = bank_start + bank_size;
+
+        if ( bank_end <= bank_start )
+            return;
+
+        free_staticmem_pages(mfn_to_page(_mfn(bank_start)),
+                             bank_size, false);
+    }
+}
+
 #ifdef CONFIG_ARM_32
 static void __init setup_mm(void)
 {
@@ -749,6 +769,8 @@ static void __init setup_mm(void)
     /* Add xenheap memory that was not already added to the boot allocator. */
     init_xenheap_pages(mfn_to_maddr(xenheap_mfn_start),
                        mfn_to_maddr(xenheap_mfn_end));
+
+    init_staticmem_pages();
 }
 #else /* CONFIG_ARM_64 */
 static void __init setup_mm(void)
@@ -802,6 +824,8 @@ static void __init setup_mm(void)
 
     setup_frametable_mappings(ram_start, ram_end);
     max_page = PFN_DOWN(ram_end);
+
+    init_staticmem_pages();
 }
 #endif
 
diff --git a/xen/common/Kconfig b/xen/common/Kconfig
index 0ddd18e11a..8f736eea82 100644
--- a/xen/common/Kconfig
+++ b/xen/common/Kconfig
@@ -67,6 +67,9 @@ config MEM_ACCESS
 config NEEDS_LIBELF
 	bool
 
+config STATIC_MEMORY
+	bool
+
 menu "Speculative hardening"
 
 config SPECULATIVE_HARDEN_ARRAY
diff --git a/xen/common/page_alloc.c b/xen/common/page_alloc.c
index a3ee5eca9e..2acb73e323 100644
--- a/xen/common/page_alloc.c
+++ b/xen/common/page_alloc.c
@@ -1519,6 +1519,26 @@ static void free_heap_pages(
     spin_unlock(&heap_lock);
 }
 
+#ifdef CONFIG_STATIC_MEMORY
+/* Equivalent of free_heap_pages to free nr_mfns pages of static memory. */
+void __init free_staticmem_pages(struct page_info *pg, unsigned long nr_mfns,
+                                 bool need_scrub)
+{
+    mfn_t mfn = page_to_mfn(pg);
+    unsigned long i;
+
+    for ( i = 0; i < nr_mfns; i++ )
+    {
+        mark_page_free(&pg[i], mfn_add(mfn, i));
+
+        if ( need_scrub )
+        {
+            /* TODO: asynchronous scrubbing for pages of static memory. */
+            scrub_one_page(pg);
+        }
+    }
+}
+#endif
 
 /*
  * Following rules applied for page offline:
diff --git a/xen/include/xen/mm.h b/xen/include/xen/mm.h
index 667f9dac83..8e8fb5a615 100644
--- a/xen/include/xen/mm.h
+++ b/xen/include/xen/mm.h
@@ -85,6 +85,12 @@ bool scrub_free_pages(void);
 } while ( false )
 #define FREE_XENHEAP_PAGE(p) FREE_XENHEAP_PAGES(p, 0)
 
+#ifdef CONFIG_STATIC_MEMORY
+/* These functions are for static memory */
+void free_staticmem_pages(struct page_info *pg, unsigned long nr_mfns,
+                          bool need_scrub);
+#endif
+
 /* Map machine page range in Xen virtual address space. */
 int map_pages_to_xen(
     unsigned long virt,
-- 
2.25.1