From 31d17076b07c8ed212b1d865b36b0c7313885ef2 Mon Sep 17 00:00:00 2001
From: Anshuman Khandual <anshuman.khandual@arm.com>
Date: Thu, 28 Apr 2022 23:16:12 -0700
Subject: [PATCH] mm/debug_vm_pgtable: drop protection_map[] usage
References: jsc#PED-1981
Patch-mainline: v5.19-rc1
Git-commit: 31d17076b07c8ed212b1d865b36b0c7313885ef2
Patch series "mm: protection_map[] cleanups".
This patch (of 2):
Although protection_map[] contains the platform defined page protection
map for a given vm_flags combination, vm_get_page_prot() is the right
interface to use. This will also reduce dependency on protection_map[]
which is going to be dropped off completely later on.
Link: https://lkml.kernel.org/r/20220404031840.588321-1-anshuman.khandual@arm.com
Link: https://lkml.kernel.org/r/20220404031840.588321-2-anshuman.khandual@arm.com
Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Michal Suchanek <msuchanek@suse.de>
---
mm/debug_vm_pgtable.c | 31 +++++++++++++++++++------------
1 file changed, 19 insertions(+), 12 deletions(-)
diff --git a/mm/debug_vm_pgtable.c b/mm/debug_vm_pgtable.c
--- a/mm/debug_vm_pgtable.c
+++ b/mm/debug_vm_pgtable.c
@@ -60,7 +60,7 @@
static void __init pte_basic_tests(unsigned long pfn, int idx)
{
- pgprot_t prot = protection_map[idx];
+ pgprot_t prot = vm_get_page_prot(idx);
pte_t pte = pfn_pte(pfn, prot);
unsigned long val = idx, *ptr = &val;
@@ -68,7 +68,7 @@ static void __init pte_basic_tests(unsig
/*
* This test needs to be executed after the given page table entry
- * is created with pfn_pte() to make sure that protection_map[idx]
+ * is created with pfn_pte() to make sure that vm_get_page_prot(idx)
* does not have the dirty bit enabled from the beginning. This is
* important for platforms like arm64 where (!PTE_RDONLY) indicate
* dirty bit being set.
@@ -145,7 +145,7 @@ static void __init pte_savedwrite_tests(
#ifdef CONFIG_TRANSPARENT_HUGEPAGE
static void __init pmd_basic_tests(unsigned long pfn, int idx)
{
- pgprot_t prot = protection_map[idx];
+ pgprot_t prot = vm_get_page_prot(idx);
unsigned long val = idx, *ptr = &val;
pmd_t pmd;
@@ -157,7 +157,7 @@ static void __init pmd_basic_tests(unsig
/*
* This test needs to be executed after the given page table entry
- * is created with pfn_pmd() to make sure that protection_map[idx]
+ * is created with pfn_pmd() to make sure that vm_get_page_prot(idx)
* does not have the dirty bit enabled from the beginning. This is
* important for platforms like arm64 where (!PTE_RDONLY) indicate
* dirty bit being set.
@@ -267,7 +267,7 @@ static void __init pmd_savedwrite_tests(
#ifdef CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD
static void __init pud_basic_tests(struct mm_struct *mm, unsigned long pfn, int idx)
{
- pgprot_t prot = protection_map[idx];
+ pgprot_t prot = vm_get_page_prot(idx);
unsigned long val = idx, *ptr = &val;
pud_t pud;
@@ -279,7 +279,7 @@ static void __init pud_basic_tests(struc
/*
* This test needs to be executed after the given page table entry
- * is created with pfn_pud() to make sure that protection_map[idx]
+ * is created with pfn_pud() to make sure that vm_get_page_prot(idx)
* does not have the dirty bit enabled from the beginning. This is
* important for platforms like arm64 where (!PTE_RDONLY) indicate
* dirty bit being set.
@@ -982,11 +982,12 @@ static int __init debug_vm_pgtable(void)
}
/*
- * protection_map[0] (or even protection_map[8]) will help create page
- * table entries with PROT_NONE permission as required for
+ * vm_get_page_prot(VM_NONE) (or even
+ * vm_get_page_prot(VM_SHARED|VM_NONE)) will help create page table
+ * entries with PROT_NONE permission as required for
* pxx_protnone_tests().
*/
- protnone = protection_map[0];
+ protnone = vm_get_page_prot(VM_NONE);
vma = vm_area_alloc(mm);
if (!vma) {
@@ -1037,12 +1038,19 @@ static int __init debug_vm_pgtable(void)
saved_ptep = pmd_pgtable(pmd);
/*
- * Iterate over the protection_map[] to make sure that all
+ * Iterate over each possible vm_flags to make sure that all
* the basic page table transformation validations just hold
* true irrespective of the starting protection value for a
* given page table entry.
+ *
+ * Protection based vm_flags combinatins are always linear
+ * and increasing i.e starting from VM_NONE and going upto
+ * (VM_SHARED | READ | WRITE | EXEC).
*/
- for (idx = 0; idx < ARRAY_SIZE(protection_map); idx++) {
+#define VM_FLAGS_START (VM_NONE)
+#define VM_FLAGS_END (VM_SHARED | VM_EXEC | VM_WRITE | VM_READ)
+
+ for (idx = VM_FLAGS_START; idx <= VM_FLAGS_END; idx++) {
pte_basic_tests(pte_aligned, idx);
pmd_basic_tests(pmd_aligned, idx);
pud_basic_tests(mm, pud_aligned, idx);