Patch "arm64/mm: define arch_get_mappable_range()" has been added to the 5.10-stable tree

[Sasha Levin <sashal@xxxxxxxxxx>]

This is a note to let you know that I've just added the patch titled

    arm64/mm: define arch_get_mappable_range()

to the 5.10-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     arm64-mm-define-arch_get_mappable_range.patch
and it can be found in the queue-5.10 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.



commit 300406ce621b676cd95235171c5ea67ee0468293
Author: Anshuman Khandual <anshuman.khandual@xxxxxxx>
Date:   Thu Feb 25 17:17:37 2021 -0800

    arm64/mm: define arch_get_mappable_range()
    
    [ Upstream commit 03aaf83fba6e5af08b5dd174c72edee9b7d9ed9b ]
    
    This overrides arch_get_mappable_range() on arm64 platform which will be
    used with recently added generic framework.  It drops
    inside_linear_region() and subsequent check in arch_add_memory() which are
    no longer required.  It also adds a VM_BUG_ON() check that would ensure
    that mhp_range_allowed() has already been called.
    
    Link: https://lkml.kernel.org/r/1612149902-7867-3-git-send-email-anshuman.khandual@xxxxxxx
    Signed-off-by: Anshuman Khandual <anshuman.khandual@xxxxxxx>
    Reviewed-by: David Hildenbrand <david@xxxxxxxxxx>
    Reviewed-by: Catalin Marinas <catalin.marinas@xxxxxxx>
    Cc: Will Deacon <will@xxxxxxxxxx>
    Cc: Ard Biesheuvel <ardb@xxxxxxxxxx>
    Cc: Mark Rutland <mark.rutland@xxxxxxx>
    Cc: Heiko Carstens <hca@xxxxxxxxxxxxx>
    Cc: Jason Wang <jasowang@xxxxxxxxxx>
    Cc: Jonathan Cameron <Jonathan.Cameron@xxxxxxxxxx>
    Cc: "Michael S. Tsirkin" <mst@xxxxxxxxxx>
    Cc: Michal Hocko <mhocko@xxxxxxxxxx>
    Cc: Oscar Salvador <osalvador@xxxxxxx>
    Cc: Pankaj Gupta <pankaj.gupta@xxxxxxxxxxxxxxx>
    Cc: Pankaj Gupta <pankaj.gupta.linux@xxxxxxxxx>
    Cc: teawater <teawaterz@xxxxxxxxxxxxxxxxx>
    Cc: Vasily Gorbik <gor@xxxxxxxxxxxxx>
    Cc: Wei Yang <richard.weiyang@xxxxxxxxxxxxxxxxx>
    Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
    Signed-off-by: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
    Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>

diff --git a/arch/arm64/mm/mmu.c b/arch/arm64/mm/mmu.c
index 6aabf1eced31..0635803463a5 100644
--- a/arch/arm64/mm/mmu.c
+++ b/arch/arm64/mm/mmu.c
@@ -1445,16 +1445,19 @@ static void __remove_pgd_mapping(pgd_t *pgdir, unsigned long start, u64 size)
 	free_empty_tables(start, end, PAGE_OFFSET, PAGE_END);
 }
 
-static bool inside_linear_region(u64 start, u64 size)
+struct range arch_get_mappable_range(void)
 {
+	struct range mhp_range;
+
 	/*
 	 * Linear mapping region is the range [PAGE_OFFSET..(PAGE_END - 1)]
 	 * accommodating both its ends but excluding PAGE_END. Max physical
 	 * range which can be mapped inside this linear mapping range, must
 	 * also be derived from its end points.
 	 */
-	return start >= __pa(_PAGE_OFFSET(vabits_actual)) &&
-	       (start + size - 1) <= __pa(PAGE_END - 1);
+	mhp_range.start = __pa(_PAGE_OFFSET(vabits_actual));
+	mhp_range.end =  __pa(PAGE_END - 1);
+	return mhp_range;
 }
 
 int arch_add_memory(int nid, u64 start, u64 size,
@@ -1462,11 +1465,7 @@ int arch_add_memory(int nid, u64 start, u64 size,
 {
 	int ret, flags = 0;
 
-	if (!inside_linear_region(start, size)) {
-		pr_err("[%llx %llx] is outside linear mapping region\n", start, start + size);
-		return -EINVAL;
-	}
-
+	VM_BUG_ON(!mhp_range_allowed(start, size, true));
 	if (rodata_full || debug_pagealloc_enabled())
 		flags = NO_BLOCK_MAPPINGS | NO_CONT_MAPPINGS;