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authorAnshuman Khandual <anshuman.khandual@arm.com>2020-11-13 13:00:14 +0530
committerWill Deacon <will@kernel.org>2020-11-13 09:45:08 +0000
commit58284a901b426e6130672e9f14c30dfd5a9dbde0 (patch)
treef562451615c467cf5a587482831bffb23d5e7f44 /arch
parent04e613ded8c26489b3e0f9101b44462f780d1a35 (diff)
downloadlinux-58284a901b426e6130672e9f14c30dfd5a9dbde0.tar.bz2
arm64/mm: Validate hotplug range before creating linear mapping
During memory hotplug process, the linear mapping should not be created for a given memory range if that would fall outside the maximum allowed linear range. Else it might cause memory corruption in the kernel virtual space. Maximum linear mapping region is [PAGE_OFFSET..(PAGE_END -1)] accommodating both its ends but excluding PAGE_END. Max physical range that can be mapped inside this linear mapping range, must also be derived from its end points. This ensures that arch_add_memory() validates memory hot add range for its potential linear mapping requirements, before creating it with __create_pgd_mapping(). Fixes: 4ab215061554 ("arm64: Add memory hotplug support") Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com> Reviewed-by: Ard Biesheuvel <ardb@kernel.org> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Will Deacon <will@kernel.org> Cc: Mark Rutland <mark.rutland@arm.com> Cc: Ard Biesheuvel <ardb@kernel.org> Cc: Steven Price <steven.price@arm.com> Cc: Robin Murphy <robin.murphy@arm.com> Cc: David Hildenbrand <david@redhat.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: linux-arm-kernel@lists.infradead.org Cc: linux-kernel@vger.kernel.org Link: https://lore.kernel.org/r/1605252614-761-1-git-send-email-anshuman.khandual@arm.com Signed-off-by: Will Deacon <will@kernel.org>
Diffstat (limited to 'arch')
-rw-r--r--arch/arm64/mm/mmu.c17
1 files changed, 17 insertions, 0 deletions
diff --git a/arch/arm64/mm/mmu.c b/arch/arm64/mm/mmu.c
index 1c0f3e02f731..ca692a815731 100644
--- a/arch/arm64/mm/mmu.c
+++ b/arch/arm64/mm/mmu.c
@@ -1444,11 +1444,28 @@ 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)
+{
+ /*
+ * 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);
+}
+
int arch_add_memory(int nid, u64 start, u64 size,
struct mhp_params *params)
{
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;
+ }
+
if (rodata_full || debug_pagealloc_enabled())
flags = NO_BLOCK_MAPPINGS | NO_CONT_MAPPINGS;