[PATCH v3 2/4] kaslr: calculate the memory region in immovable node

[Chao Fan]

If there is no immovable memory region specified, go on the old code.
There are several conditons:
1. CONFIG_MEMORY_HOTPLUG is not specified to y.
2. immovable_mem= is not specified.

Otherwise, calculate the intersecting between memmap entry and
immovable memory.

Signed-off-by: Chao Fan <fanc.f...@cn.fujitsu.com>
---
 arch/x86/boot/compressed/kaslr.c | 59 ++++++++++++++++++++++++++++++++++------
 1 file changed, 51 insertions(+), 8 deletions(-)

diff --git a/arch/x86/boot/compressed/kaslr.c b/arch/x86/boot/compressed/kaslr.c
index 0bbbaf5f6370..e3a3b6132da0 100644
--- a/arch/x86/boot/compressed/kaslr.c
+++ b/arch/x86/boot/compressed/kaslr.c
@@ -635,6 +635,39 @@ static void process_mem_region(struct mem_vector *entry,
        }
 }
 
+static bool process_immovable_mem(struct mem_vector region,
+                                 unsigned long long minimum,
+                                 unsigned long long image_size)
+{
+       int i;
+
+       /*
+        * Walk all immovable regions, and filter the intersection
+        * to process_mem_region.
+        */
+       for (i = 0; i < num_immovable_region; i++) {
+               struct mem_vector entry;
+               unsigned long long start, end, entry_end;
+
+               start = immovable_mem[i].start;
+               end = start + immovable_mem[i].size;
+
+               entry.start = clamp(region.start, start, end);
+               entry_end = clamp(region.start + region.size, start, end);
+
+               if (entry.start < entry_end) {
+                       entry.size = entry_end - entry.start;
+                       process_mem_region(&entry, minimum, image_size);
+               }
+
+               if (slot_area_index == MAX_SLOT_AREA) {
+                       debug_putstr("Aborted memmap scan (slot_areas 
full)!\n");
+                       return 1;
+               }
+       }
+       return 0;
+}
+
 #ifdef CONFIG_EFI
 /*
  * Returns true if mirror region found (and must have been processed
@@ -700,11 +733,16 @@ process_efi_entries(unsigned long minimum, unsigned long 
image_size)
 
                region.start = md->phys_addr;
                region.size = md->num_pages << EFI_PAGE_SHIFT;
-               process_mem_region(&region, minimum, image_size);
-               if (slot_area_index == MAX_SLOT_AREA) {
-                       debug_putstr("Aborted EFI scan (slot_areas full)!\n");
+
+               /* If no immovable_mem stored, use region directly */
+               if (num_immovable_region == 0) {
+                       process_mem_region(&region, minimum, image_size);
+                       if (slot_area_index == MAX_SLOT_AREA) {
+                               debug_putstr("Aborted memmap scan (slot_areas 
full)!\n");
+                               break;
+                       }
+               } else if (process_immovable_mem(region, minimum, image_size))
                        break;
-               }
        }
        return true;
 }
@@ -731,11 +769,16 @@ static void process_e820_entries(unsigned long minimum,
                        continue;
                region.start = entry->addr;
                region.size = entry->size;
-               process_mem_region(&region, minimum, image_size);
-               if (slot_area_index == MAX_SLOT_AREA) {
-                       debug_putstr("Aborted e820 scan (slot_areas full)!\n");
+
+               /* If no immovable_mem stored, use region directly */
+               if (num_immovable_region == 0) {
+                       process_mem_region(&region, minimum, image_size);
+                       if (slot_area_index == MAX_SLOT_AREA) {
+                               debug_putstr("Aborted memmap scan (slot_areas 
full)!\n");
+                               break;
+                       }
+               } else if (process_immovable_mem(region, minimum, image_size))
                        break;
-               }
        }
 }
 
-- 
2.14.3