mm/debug_vm_pgtable: use struct pgtable_debug_args in PTE modifying tests

This uses struct pgtable_debug_args in PTE modifying tests.  The allocated
page is used as set_pte_at() is used there.  The tests are skipped if the
allocated page doesn't exist.  It's notable that args->ptep need to be
mapped before the tests.  The reason why we don't map args->ptep at the
beginning is PTE entry is only mapped and accessible in atomic context
when CONFIG_HIGHPTE is enabled.  So we avoid to do that so that atomic
context is only enabled if needed.

Besides, the unused variable @pte_aligned and @ptep in debug_vm_pgtable()
are dropped.

Link: https://lkml.kernel.org/r/20210809092631.1888748-8-gshan@redhat.comSigned-off-by: Gavin Shan <gshan@redhat.com>
Reviewed-by: Anshuman Khandual <anshuman.khandual@arm.com>
Tested-by: Christophe Leroy <christophe.leroy@csgroup.eu>	[powerpc 8xx]
Tested-by: Gerald Schaefer <gerald.schaefer@linux.ibm.com>	[s390]
Cc: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Chunyu Hu <chuhu@redhat.com>
Cc: Qian Cai <cai@lca.pw>
Cc: Vineet Gupta <vgupta@synopsys.com>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm/debug_vm_pgtable.c

@@ -117,10 +117,7 @@ static void __init pte_basic_tests(struct pgtable_debug_args *args, int idx)
 	WARN_ON(!pte_dirty(pte_wrprotect(pte_mkdirty(pte))));
 }
 
-static void __init pte_advanced_tests(struct mm_struct *mm,
-				      struct vm_area_struct *vma, pte_t *ptep,
-				      unsigned long pfn, unsigned long vaddr,
-				      pgprot_t prot)
+static void __init pte_advanced_tests(struct pgtable_debug_args *args)
 {
 	pte_t pte;
 
@@ -129,35 +126,37 @@ static void __init pte_advanced_tests(struct mm_struct *mm,
 	 * This requires set_pte_at to be not used to update an
 	 * existing pte entry. Clear pte before we do set_pte_at
 	 */
+	if (args->pte_pfn == ULONG_MAX)
+		return;
 
 	pr_debug("Validating PTE advanced\n");
-	pte = pfn_pte(pfn, prot);
-	set_pte_at(mm, vaddr, ptep, pte);
-	ptep_set_wrprotect(mm, vaddr, ptep);
-	pte = ptep_get(ptep);
+	pte = pfn_pte(args->pte_pfn, args->page_prot);
+	set_pte_at(args->mm, args->vaddr, args->ptep, pte);
+	ptep_set_wrprotect(args->mm, args->vaddr, args->ptep);
+	pte = ptep_get(args->ptep);
 	WARN_ON(pte_write(pte));
-	ptep_get_and_clear(mm, vaddr, ptep);
-	pte = ptep_get(ptep);
+	ptep_get_and_clear(args->mm, args->vaddr, args->ptep);
+	pte = ptep_get(args->ptep);
 	WARN_ON(!pte_none(pte));
 
-	pte = pfn_pte(pfn, prot);
+	pte = pfn_pte(args->pte_pfn, args->page_prot);
 	pte = pte_wrprotect(pte);
 	pte = pte_mkclean(pte);
-	set_pte_at(mm, vaddr, ptep, pte);
+	set_pte_at(args->mm, args->vaddr, args->ptep, pte);
 	pte = pte_mkwrite(pte);
 	pte = pte_mkdirty(pte);
-	ptep_set_access_flags(vma, vaddr, ptep, pte, 1);
-	pte = ptep_get(ptep);
+	ptep_set_access_flags(args->vma, args->vaddr, args->ptep, pte, 1);
+	pte = ptep_get(args->ptep);
 	WARN_ON(!(pte_write(pte) && pte_dirty(pte)));
-	ptep_get_and_clear_full(mm, vaddr, ptep, 1);
-	pte = ptep_get(ptep);
+	ptep_get_and_clear_full(args->mm, args->vaddr, args->ptep, 1);
+	pte = ptep_get(args->ptep);
 	WARN_ON(!pte_none(pte));
 
-	pte = pfn_pte(pfn, prot);
+	pte = pfn_pte(args->pte_pfn, args->page_prot);
 	pte = pte_mkyoung(pte);
-	set_pte_at(mm, vaddr, ptep, pte);
-	ptep_test_and_clear_young(vma, vaddr, ptep);
-	pte = ptep_get(ptep);
+	set_pte_at(args->mm, args->vaddr, args->ptep, pte);
+	ptep_test_and_clear_young(args->vma, args->vaddr, args->ptep);
+	pte = ptep_get(args->ptep);
 	WARN_ON(pte_young(pte));
 }
 
@@ -618,20 +617,21 @@ static void __init pgd_populate_tests(struct mm_struct *mm, pgd_t *pgdp,
 }
 #endif /* PAGETABLE_P4D_FOLDED */
 
-static void __init pte_clear_tests(struct mm_struct *mm, pte_t *ptep,
-				   unsigned long pfn, unsigned long vaddr,
-				   pgprot_t prot)
+static void __init pte_clear_tests(struct pgtable_debug_args *args)
 {
-	pte_t pte = pfn_pte(pfn, prot);
+	pte_t pte = pfn_pte(args->pte_pfn, args->page_prot);
+
+	if (args->pte_pfn == ULONG_MAX)
+		return;
 
 	pr_debug("Validating PTE clear\n");
 #ifndef CONFIG_RISCV
 	pte = __pte(pte_val(pte) | RANDOM_ORVALUE);
 #endif
-	set_pte_at(mm, vaddr, ptep, pte);
+	set_pte_at(args->mm, args->vaddr, args->ptep, pte);
 	barrier();
-	pte_clear(mm, vaddr, ptep);
-	pte = ptep_get(ptep);
+	pte_clear(args->mm, args->vaddr, args->ptep);
+	pte = ptep_get(args->ptep);
 	WARN_ON(!pte_none(pte));
 }
 
@@ -1221,11 +1221,10 @@ static int __init debug_vm_pgtable(void)
 	p4d_t *p4dp, *saved_p4dp;
 	pud_t *pudp, *saved_pudp;
 	pmd_t *pmdp, *saved_pmdp, pmd;
-	pte_t *ptep;
 	pgtable_t saved_ptep;
 	pgprot_t prot;
 	phys_addr_t paddr;
-	unsigned long vaddr, pte_aligned, pmd_aligned;
+	unsigned long vaddr, pmd_aligned;
 	unsigned long pud_aligned;
 	spinlock_t *ptl = NULL;
 	int idx, ret;
@@ -1260,10 +1259,8 @@ static int __init debug_vm_pgtable(void)
 	 */
 	paddr = __pa_symbol(&start_kernel);
 
-	pte_aligned = (paddr & PAGE_MASK) >> PAGE_SHIFT;
 	pmd_aligned = (paddr & PMD_MASK) >> PAGE_SHIFT;
 	pud_aligned = (paddr & PUD_MASK) >> PAGE_SHIFT;
-	WARN_ON(!pfn_valid(pte_aligned));
 
 	pgdp = pgd_offset(mm, vaddr);
 	p4dp = p4d_alloc(mm, pgdp, vaddr);
@@ -1345,10 +1342,10 @@ static int __init debug_vm_pgtable(void)
 	 * proper page table lock.
 	 */
 
-	ptep = pte_offset_map_lock(mm, pmdp, vaddr, &ptl);
-	pte_clear_tests(mm, ptep, pte_aligned, vaddr, prot);
-	pte_advanced_tests(mm, vma, ptep, pte_aligned, vaddr, prot);
-	pte_unmap_unlock(ptep, ptl);
+	args.ptep = pte_offset_map_lock(args.mm, args.pmdp, args.vaddr, &ptl);
+	pte_clear_tests(&args);
+	pte_advanced_tests(&args);
+	pte_unmap_unlock(args.ptep, ptl);
 
 	ptl = pmd_lock(mm, pmdp);
 	pmd_clear_tests(mm, pmdp);