The patch titled
Subject: mm/debug_vm_pgtable: drop protection_map[] usage
has been added to the -mm tree. Its filename is
mm-debug_vm_pgtable-drop-protection_map-usage.patch
This patch should soon appear at
https://ozlabs.org/~akpm/mmots/broken-out/mm-debug_vm_pgtable-drop-protection_map-usage.patch
and later at
https://ozlabs.org/~akpm/mmotm/broken-out/mm-debug_vm_pgtable-drop-protection_map-usage.patch
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From: Anshuman Khandual <anshuman.khandual@xxxxxxx>
Subject: mm/debug_vm_pgtable: drop protection_map[] usage
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@xxxxxxx
Link: https://lkml.kernel.org/r/20220404031840.588321-2-anshuman.khandual@xxxxxxx
Signed-off-by: Anshuman Khandual <anshuman.khandual@xxxxxxx>
Cc: Christoph Hellwig <hch@xxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/debug_vm_pgtable.c | 31 +++++++++++++++++++------------
1 file changed, 19 insertions(+), 12 deletions(-)
--- a/mm/debug_vm_pgtable.c~mm-debug_vm_pgtable-drop-protection_map-usage
+++ a/mm/debug_vm_pgtable.c
@@ -93,7 +93,7 @@ struct pgtable_debug_args {
static void __init pte_basic_tests(struct pgtable_debug_args *args, int idx)
{
- pgprot_t prot = protection_map[idx];
+ pgprot_t prot = vm_get_page_prot(idx);
pte_t pte = pfn_pte(args->fixed_pte_pfn, prot);
unsigned long val = idx, *ptr = &val;
@@ -101,7 +101,7 @@ static void __init pte_basic_tests(struc
/*
* 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.
@@ -190,7 +190,7 @@ static void __init pte_savedwrite_tests(
#ifdef CONFIG_TRANSPARENT_HUGEPAGE
static void __init pmd_basic_tests(struct pgtable_debug_args *args, 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;
@@ -202,7 +202,7 @@ static void __init pmd_basic_tests(struc
/*
* 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.
@@ -325,7 +325,7 @@ static void __init pmd_savedwrite_tests(
#ifdef CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD
static void __init pud_basic_tests(struct pgtable_debug_args *args, 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;
@@ -337,7 +337,7 @@ 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.
@@ -1119,14 +1119,14 @@ static int __init init_args(struct pgtab
/*
* Initialize the debugging data.
*
- * protection_map[0] (or even protection_map[8]) will help create
- * page table entries with PROT_NONE permission as required for
- * pxx_protnone_tests().
+ * vm_get_page_prot(VM_NONE) or vm_get_page_prot(VM_SHARED|VM_NONE)
+ * will help create page table entries with PROT_NONE permission as
+ * required for pxx_protnone_tests().
*/
memset(args, 0, sizeof(*args));
args->vaddr = get_random_vaddr();
args->page_prot = vm_get_page_prot(VMFLAGS);
- args->page_prot_none = protection_map[0];
+ args->page_prot_none = vm_get_page_prot(VM_NONE);
args->is_contiguous_page = false;
args->pud_pfn = ULONG_MAX;
args->pmd_pfn = ULONG_MAX;
@@ -1261,12 +1261,19 @@ static int __init debug_vm_pgtable(void)
return ret;
/*
- * 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(&args, idx);
pmd_basic_tests(&args, idx);
pud_basic_tests(&args, idx);
_
Patches currently in -mm which might be from anshuman.khandual@xxxxxxx are
mm-debug_vm_pgtable-drop-protection_map-usage.patch
mm-mmap-clarify-protection_map-indices.patch
