[PATCH 09/12] Revert "xen/arm: mm: Initialize page-tables earlier"

[Carlo Nonato <carlo.nonato@xxxxxxxxxxxxxxx>]

From: Luca Miccio <lucmiccio@xxxxxxxxx>

This reverts commit 3a5d341681af650825bbe3bee9be5d187da35080.

The cache coloring support will be configurable within the Xen command line,
but it will be initialized before the page-tables; this is necessary
for coloring the hypervisor itself beacuse we will create a specific
mapping for it that could be configured using some command line options.
In order to parse all the needed information from the device tree, we
need to revert the above commit and restore the previous order for
page-tables initialization.

Signed-off-by: Carlo Nonato <carlo.nonato@xxxxxxxxxxxxxxx>
Signed-off-by: Marco Solieri <marco.solieri@xxxxxxxxxxxxxxx>
---
 xen/arch/arm/mm.c    | 33 ++++++++++++++++++++-------------
 xen/arch/arm/setup.c |  4 ++--
 2 files changed, 22 insertions(+), 15 deletions(-)

diff --git a/xen/arch/arm/mm.c b/xen/arch/arm/mm.c
index b42cddb1b4..1afa02b4af 100644
--- a/xen/arch/arm/mm.c
+++ b/xen/arch/arm/mm.c
@@ -368,6 +368,17 @@ static inline lpae_t pte_of_xenaddr(vaddr_t va)
     return mfn_to_xen_entry(maddr_to_mfn(ma), MT_NORMAL);
 }
 
+static void __init create_boot_mappings(unsigned long virt_offset,
+                                        mfn_t base_mfn)
+{
+    lpae_t pte;
+
+    pte = mfn_to_xen_entry(base_mfn, MT_NORMAL);
+    write_pte(&boot_second[second_table_offset(virt_offset)], pte);
+    flush_xen_tlb_local();
+}
+
+/* Map the FDT in the early boot page table */
 void * __init early_fdt_map(paddr_t fdt_paddr)
 {
     /* We are using 2MB superpage for mapping the FDT */
@@ -375,7 +386,6 @@ void * __init early_fdt_map(paddr_t fdt_paddr)
     paddr_t offset;
     void *fdt_virt;
     uint32_t size;
-    int rc;
 
     /*
      * Check whether the physical FDT address is set and meets the minimum
@@ -391,12 +401,7 @@ void * __init early_fdt_map(paddr_t fdt_paddr)
     /* The FDT is mapped using 2MB superpage */
     BUILD_BUG_ON(BOOT_FDT_VIRT_START % SZ_2M);
 
-    rc = map_pages_to_xen(BOOT_FDT_VIRT_START, maddr_to_mfn(base_paddr),
-                          SZ_2M >> PAGE_SHIFT,
-                          PAGE_HYPERVISOR_RO | _PAGE_BLOCK);
-    if ( rc )
-        panic("Unable to map the device-tree.\n");
-
+    create_boot_mappings(BOOT_FDT_VIRT_START, maddr_to_mfn(base_paddr));
 
     offset = fdt_paddr % SECOND_SIZE;
     fdt_virt = (void *)BOOT_FDT_VIRT_START + offset;
@@ -410,12 +415,8 @@ void * __init early_fdt_map(paddr_t fdt_paddr)
 
     if ( (offset + size) > SZ_2M )
     {
-        rc = map_pages_to_xen(BOOT_FDT_VIRT_START + SZ_2M,
-                              maddr_to_mfn(base_paddr + SZ_2M),
-                              SZ_2M >> PAGE_SHIFT,
-                              PAGE_HYPERVISOR_RO | _PAGE_BLOCK);
-        if ( rc )
-            panic("Unable to map the device-tree\n");
+        create_boot_mappings(BOOT_FDT_VIRT_START + SZ_2M,
+                             maddr_to_mfn(base_paddr + SZ_2M));
     }
 
     return fdt_virt;
@@ -514,6 +515,12 @@ void __init setup_pagetables(unsigned long 
boot_phys_offset)
     pte.pt.table = 1;
     xen_second[second_table_offset(FIXMAP_ADDR(0))] = pte;
 
+    /* ... DTB */
+    pte = boot_second[second_table_offset(BOOT_FDT_VIRT_START)];
+    xen_second[second_table_offset(BOOT_FDT_VIRT_START)] = pte;
+    pte = boot_second[second_table_offset(BOOT_FDT_VIRT_START + SZ_2M)];
+    xen_second[second_table_offset(BOOT_FDT_VIRT_START + SZ_2M)] = pte;
+
 #ifdef CONFIG_ARM_64
     ttbr = (uintptr_t) xen_pgtable + phys_offset;
 #else
diff --git a/xen/arch/arm/setup.c b/xen/arch/arm/setup.c
index 611c93ad7d..bdfc05bf61 100644
--- a/xen/arch/arm/setup.c
+++ b/xen/arch/arm/setup.c
@@ -910,8 +910,6 @@ void __init start_xen(unsigned long boot_phys_offset,
     /* Initialize traps early allow us to get backtrace when an error occurred 
*/
     init_traps();
 
-    setup_pagetables(boot_phys_offset);
-
     smp_clear_cpu_maps();
 
     device_tree_flattened = early_fdt_map(fdt_paddr);
@@ -938,6 +936,8 @@ void __init start_xen(unsigned long boot_phys_offset,
                              (paddr_t)(uintptr_t)(_end - _start + 1), false);
     BUG_ON(!xen_bootmodule);
 
+    setup_pagetables(boot_phys_offset);
+
     setup_mm();
 
     /* Parse the ACPI tables for possible boot-time configuration */
-- 
2.34.1