On 19.11.23 17:57, Alexandru Elisei wrote:
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.elisei@xxxxxxx>
---
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;
+}
+
Looks like something that ordinary CMA provides. See cma_activate_area().
Can't we find a way to let CMA do CMA thingies and only be a user of
that? What would be required to make the performance issue you spelled
out in the cover letter be gone and not have to open-code that in arch code?
--
Cheers,
David / dhildenb
