mm/debug_vm_pgtable: add tests for __HAVE_ARCH_PTE_SWP_EXCLUSIVE

Let's test that __HAVE_ARCH_PTE_SWP_EXCLUSIVE works as expected.

Link: https://lkml.kernel.org/r/20220329164329.208407-3-david@redhat.comSigned-off-by: David Hildenbrand <david@redhat.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Don Dutile <ddutile@redhat.com>
Cc: Gerald Schaefer <gerald.schaefer@linux.ibm.com>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Jann Horn <jannh@google.com>
Cc: Jason Gunthorpe <jgg@nvidia.com>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Liang Zhang <zhangliang5@huawei.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Mike Rapoport <rppt@linux.ibm.com>
Cc: Nadav Amit <namit@vmware.com>
Cc: Oded Gabbay <oded.gabbay@gmail.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Pedro Demarchi Gomes <pedrodemargomes@gmail.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Rik van Riel <riel@surriel.com>
Cc: Roman Gushchin <guro@fb.com>
Cc: Shakeel Butt <shakeelb@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

mm/debug_vm_pgtable.c

@@ -837,6 +837,19 @@ static void __init pmd_soft_dirty_tests(struct pgtable_debug_args *args) { }
 static void __init pmd_swap_soft_dirty_tests(struct pgtable_debug_args *args) { }
 #endif /* CONFIG_TRANSPARENT_HUGEPAGE */
 
+static void __init pte_swap_exclusive_tests(struct pgtable_debug_args *args)
+{
+#ifdef __HAVE_ARCH_PTE_SWP_EXCLUSIVE
+	pte_t pte = pfn_pte(args->fixed_pte_pfn, args->page_prot);
+
+	pr_debug("Validating PTE swap exclusive\n");
+	pte = pte_swp_mkexclusive(pte);
+	WARN_ON(!pte_swp_exclusive(pte));
+	pte = pte_swp_clear_exclusive(pte);
+	WARN_ON(pte_swp_exclusive(pte));
+#endif /* __HAVE_ARCH_PTE_SWP_EXCLUSIVE */
+}
+
 static void __init pte_swap_tests(struct pgtable_debug_args *args)
 {
 	swp_entry_t swp;
@@ -1295,6 +1308,8 @@ static int __init debug_vm_pgtable(void)
 	pte_swap_soft_dirty_tests(&args);
 	pmd_swap_soft_dirty_tests(&args);
 
+	pte_swap_exclusive_tests(&args);
+
 	pte_swap_tests(&args);
 	pmd_swap_tests(&args);