[PATCH RFC v2 15/27] arm64: mte: Check that tag storage blocks are in the same zone

[Alexandru Elisei]

alloc_contig_range() requires that the requested pages are in the same
zone. Check that this is indeed the case before initializing the tag
storage blocks.

Signed-off-by: Alexandru Elisei <alexandru.eli...@arm.com>
---
 arch/arm64/kernel/mte_tag_storage.c | 33 +++++++++++++++++++++++++++++
 1 file changed, 33 insertions(+)

diff --git a/arch/arm64/kernel/mte_tag_storage.c 
b/arch/arm64/kernel/mte_tag_storage.c
index 8b9bedf7575d..fd63430d4dc0 100644
--- a/arch/arm64/kernel/mte_tag_storage.c
+++ b/arch/arm64/kernel/mte_tag_storage.c
@@ -265,6 +265,35 @@ void __init mte_tag_storage_init(void)
        }
 }
 
+/* alloc_contig_range() requires all pages to be in the same zone. */
+static int __init mte_tag_storage_check_zone(void)
+{
+       struct range *tag_range;
+       struct zone *zone;
+       unsigned long pfn;
+       u32 block_size;
+       int i, j;
+
+       for (i = 0; i < num_tag_regions; i++) {
+               block_size = tag_regions[i].block_size;
+               if (block_size == 1)
+                       continue;
+
+               tag_range = &tag_regions[i].tag_range;
+               for (pfn = tag_range->start; pfn <= tag_range->end; pfn += 
block_size) {
+                       zone = page_zone(pfn_to_page(pfn));
+                       for (j = 1; j < block_size; j++) {
+                               if (page_zone(pfn_to_page(pfn + j)) != zone) {
+                                       pr_err("Tag storage block pages in 
different zones");
+                                       return -EINVAL;
+                               }
+                       }
+               }
+       }
+
+        return 0;
+}
+
 static int __init mte_tag_storage_activate_regions(void)
 {
        phys_addr_t dram_start, dram_end;
@@ -321,6 +350,10 @@ static int __init mte_tag_storage_activate_regions(void)
                goto out_disabled;
        }
 
+       ret = mte_tag_storage_check_zone();
+       if (ret)
+               goto out_disabled;
+
        for (i = 0; i < num_tag_regions; i++) {
                tag_range = &tag_regions[i].tag_range;
                for (pfn = tag_range->start; pfn <= tag_range->end; pfn += 
pageblock_nr_pages)
-- 
2.42.1