This patch removes page-shift bits (scheduled to remove since 3.11) and
completes migration to the new bit layout. Also it cleans messy macro.

Signed-off-by: Konstantin Khlebnikov <khlebni...@yandex-team.ru>
---
 fs/proc/task_mmu.c    |  150 +++++++++++++++++--------------------------------
 tools/vm/page-types.c |   25 +++-----
 2 files changed, 61 insertions(+), 114 deletions(-)

diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c
index 270bf7cbc8a5..c05db6acdc35 100644
--- a/fs/proc/task_mmu.c
+++ b/fs/proc/task_mmu.c
@@ -710,23 +710,6 @@ const struct file_operations proc_tid_smaps_operations = {
        .release        = proc_map_release,
 };
 
-/*
- * We do not want to have constant page-shift bits sitting in
- * pagemap entries and are about to reuse them some time soon.
- *
- * Here's the "migration strategy":
- * 1. when the system boots these bits remain what they are,
- *    but a warning about future change is printed in log;
- * 2. once anyone clears soft-dirty bits via clear_refs file,
- *    these flag is set to denote, that user is aware of the
- *    new API and those page-shift bits change their meaning.
- *    The respective warning is printed in dmesg;
- * 3. In a couple of releases we will remove all the mentions
- *    of page-shift in pagemap entries.
- */
-
-static bool soft_dirty_cleared __read_mostly;
-
 enum clear_refs_types {
        CLEAR_REFS_ALL = 1,
        CLEAR_REFS_ANON,
@@ -887,13 +870,6 @@ static ssize_t clear_refs_write(struct file *file, const 
char __user *buf,
        if (type < CLEAR_REFS_ALL || type >= CLEAR_REFS_LAST)
                return -EINVAL;
 
-       if (type == CLEAR_REFS_SOFT_DIRTY) {
-               soft_dirty_cleared = true;
-               pr_warn_once("The pagemap bits 55-60 has changed their meaning!"
-                            " See the linux/Documentation/vm/pagemap.txt for "
-                            "details.\n");
-       }
-
        task = get_proc_task(file_inode(file));
        if (!task)
                return -ESRCH;
@@ -961,36 +937,24 @@ typedef struct {
 struct pagemapread {
        int pos, len;           /* units: PM_ENTRY_BYTES, not bytes */
        pagemap_entry_t *buffer;
-       bool v2;
 };
 
 #define PAGEMAP_WALK_SIZE      (PMD_SIZE)
 #define PAGEMAP_WALK_MASK      (PMD_MASK)
 
-#define PM_ENTRY_BYTES      sizeof(pagemap_entry_t)
-#define PM_STATUS_BITS      3
-#define PM_STATUS_OFFSET    (64 - PM_STATUS_BITS)
-#define PM_STATUS_MASK      (((1LL << PM_STATUS_BITS) - 1) << PM_STATUS_OFFSET)
-#define PM_STATUS(nr)       (((nr) << PM_STATUS_OFFSET) & PM_STATUS_MASK)
-#define PM_PSHIFT_BITS      6
-#define PM_PSHIFT_OFFSET    (PM_STATUS_OFFSET - PM_PSHIFT_BITS)
-#define PM_PSHIFT_MASK      (((1LL << PM_PSHIFT_BITS) - 1) << PM_PSHIFT_OFFSET)
-#define __PM_PSHIFT(x)      (((u64) (x) << PM_PSHIFT_OFFSET) & PM_PSHIFT_MASK)
-#define PM_PFRAME_MASK      ((1LL << PM_PSHIFT_OFFSET) - 1)
-#define PM_PFRAME(x)        ((x) & PM_PFRAME_MASK)
-/* in "new" pagemap pshift bits are occupied with more status bits */
-#define PM_STATUS2(v2, x)   (__PM_PSHIFT(v2 ? x : PAGE_SHIFT))
-
-#define __PM_SOFT_DIRTY      (1LL)
-#define PM_PRESENT          PM_STATUS(4LL)
-#define PM_SWAP             PM_STATUS(2LL)
-#define PM_FILE             PM_STATUS(1LL)
-#define PM_NOT_PRESENT(v2)  PM_STATUS2(v2, 0)
+#define PM_ENTRY_BYTES         sizeof(pagemap_entry_t)
+#define PM_PFRAME_BITS         55
+#define PM_PFRAME_MASK         GENMASK_ULL(PM_PFRAME_BITS - 1, 0)
+#define PM_SOFT_DIRTY          BIT_ULL(55)
+#define PM_FILE                        BIT_ULL(61)
+#define PM_SWAP                        BIT_ULL(62)
+#define PM_PRESENT             BIT_ULL(63)
+
 #define PM_END_OF_BUFFER    1
 
-static inline pagemap_entry_t make_pme(u64 val)
+static inline pagemap_entry_t make_pme(u64 frame, u64 flags)
 {
-       return (pagemap_entry_t) { .pme = val };
+       return (pagemap_entry_t) { .pme = (frame & PM_PFRAME_MASK) | flags };
 }
 
 static int add_to_pagemap(unsigned long addr, pagemap_entry_t *pme,
@@ -1011,7 +975,7 @@ static int pagemap_pte_hole(unsigned long start, unsigned 
long end,
 
        while (addr < end) {
                struct vm_area_struct *vma = find_vma(walk->mm, addr);
-               pagemap_entry_t pme = make_pme(PM_NOT_PRESENT(pm->v2));
+               pagemap_entry_t pme = make_pme(0, 0);
                /* End of address space hole, which we mark as non-present. */
                unsigned long hole_end;
 
@@ -1031,7 +995,7 @@ static int pagemap_pte_hole(unsigned long start, unsigned 
long end,
 
                /* Addresses in the VMA. */
                if (vma->vm_flags & VM_SOFTDIRTY)
-                       pme.pme |= PM_STATUS2(pm->v2, __PM_SOFT_DIRTY);
+                       pme = make_pme(0, PM_SOFT_DIRTY);
                for (; addr < min(end, vma->vm_end); addr += PAGE_SIZE) {
                        err = add_to_pagemap(addr, &pme, pm);
                        if (err)
@@ -1042,63 +1006,61 @@ out:
        return err;
 }
 
-static void pte_to_pagemap_entry(pagemap_entry_t *pme, struct pagemapread *pm,
+static pagemap_entry_t pte_to_pagemap_entry(struct pagemapread *pm,
                struct vm_area_struct *vma, unsigned long addr, pte_t pte)
 {
-       u64 frame, flags;
+       u64 frame = 0, flags = 0;
        struct page *page = NULL;
-       int flags2 = 0;
 
        if (pte_present(pte)) {
                frame = pte_pfn(pte);
-               flags = PM_PRESENT;
+               flags |= PM_PRESENT;
                page = vm_normal_page(vma, addr, pte);
                if (pte_soft_dirty(pte))
-                       flags2 |= __PM_SOFT_DIRTY;
+                       flags |= PM_SOFT_DIRTY;
        } else if (is_swap_pte(pte)) {
                swp_entry_t entry;
                if (pte_swp_soft_dirty(pte))
-                       flags2 |= __PM_SOFT_DIRTY;
+                       flags |= PM_SOFT_DIRTY;
                entry = pte_to_swp_entry(pte);
                frame = swp_type(entry) |
                        (swp_offset(entry) << MAX_SWAPFILES_SHIFT);
-               flags = PM_SWAP;
+               flags |= PM_SWAP;
                if (is_migration_entry(entry))
                        page = migration_entry_to_page(entry);
-       } else {
-               if (vma->vm_flags & VM_SOFTDIRTY)
-                       flags2 |= __PM_SOFT_DIRTY;
-               *pme = make_pme(PM_NOT_PRESENT(pm->v2) | PM_STATUS2(pm->v2, 
flags2));
-               return;
        }
 
        if (page && !PageAnon(page))
                flags |= PM_FILE;
-       if ((vma->vm_flags & VM_SOFTDIRTY))
-               flags2 |= __PM_SOFT_DIRTY;
+       if (vma->vm_flags & VM_SOFTDIRTY)
+               flags |= PM_SOFT_DIRTY;
 
-       *pme = make_pme(PM_PFRAME(frame) | PM_STATUS2(pm->v2, flags2) | flags);
+       return make_pme(frame, flags);
 }
 
 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
-static void thp_pmd_to_pagemap_entry(pagemap_entry_t *pme, struct pagemapread 
*pm,
-               pmd_t pmd, int offset, int pmd_flags2)
+static pagemap_entry_t thp_pmd_to_pagemap_entry(struct pagemapread *pm,
+               pmd_t pmd, int offset, u64 flags)
 {
+       u64 frame = 0;
+
        /*
         * Currently pmd for thp is always present because thp can not be
         * swapped-out, migrated, or HWPOISONed (split in such cases instead.)
         * This if-check is just to prepare for future implementation.
         */
-       if (pmd_present(pmd))
-               *pme = make_pme(PM_PFRAME(pmd_pfn(pmd) + offset)
-                               | PM_STATUS2(pm->v2, pmd_flags2) | PM_PRESENT);
-       else
-               *pme = make_pme(PM_NOT_PRESENT(pm->v2) | PM_STATUS2(pm->v2, 
pmd_flags2));
+       if (pmd_present(pmd)) {
+               frame = pmd_pfn(pmd) + offset;
+               flags |= PM_PRESENT;
+       }
+
+       return make_pme(frame, flags);
 }
 #else
-static inline void thp_pmd_to_pagemap_entry(pagemap_entry_t *pme, struct 
pagemapread *pm,
-               pmd_t pmd, int offset, int pmd_flags2)
+static pagemap_entry_t thp_pmd_to_pagemap_entry(struct pagemapread *pm,
+               pmd_t pmd, int offset, u64 flags)
 {
+       return make_pme(0, 0);
 }
 #endif
 
@@ -1112,12 +1074,10 @@ static int pagemap_pte_range(pmd_t *pmd, unsigned long 
addr, unsigned long end,
        int err = 0;
 
        if (pmd_trans_huge_lock(pmd, vma, &ptl) == 1) {
-               int pmd_flags2;
+               u64 flags = 0;
 
                if ((vma->vm_flags & VM_SOFTDIRTY) || pmd_soft_dirty(*pmd))
-                       pmd_flags2 = __PM_SOFT_DIRTY;
-               else
-                       pmd_flags2 = 0;
+                       flags |= PM_SOFT_DIRTY;
 
                for (; addr != end; addr += PAGE_SIZE) {
                        unsigned long offset;
@@ -1125,7 +1085,7 @@ static int pagemap_pte_range(pmd_t *pmd, unsigned long 
addr, unsigned long end,
 
                        offset = (addr & ~PAGEMAP_WALK_MASK) >>
                                        PAGE_SHIFT;
-                       thp_pmd_to_pagemap_entry(&pme, pm, *pmd, offset, 
pmd_flags2);
+                       pme = thp_pmd_to_pagemap_entry(pm, *pmd, offset, flags);
                        err = add_to_pagemap(addr, &pme, pm);
                        if (err)
                                break;
@@ -1145,7 +1105,7 @@ static int pagemap_pte_range(pmd_t *pmd, unsigned long 
addr, unsigned long end,
        for (; addr < end; pte++, addr += PAGE_SIZE) {
                pagemap_entry_t pme;
 
-               pte_to_pagemap_entry(&pme, pm, vma, addr, *pte);
+               pme = pte_to_pagemap_entry(pm, vma, addr, *pte);
                err = add_to_pagemap(addr, &pme, pm);
                if (err)
                        break;
@@ -1158,16 +1118,17 @@ static int pagemap_pte_range(pmd_t *pmd, unsigned long 
addr, unsigned long end,
 }
 
 #ifdef CONFIG_HUGETLB_PAGE
-static void huge_pte_to_pagemap_entry(pagemap_entry_t *pme, struct pagemapread 
*pm,
-                                       pte_t pte, int offset, int flags2)
+static pagemap_entry_t huge_pte_to_pagemap_entry(struct pagemapread *pm,
+                                       pte_t pte, int offset, u64 flags)
 {
-       if (pte_present(pte))
-               *pme = make_pme(PM_PFRAME(pte_pfn(pte) + offset)        |
-                               PM_STATUS2(pm->v2, flags2)              |
-                               PM_PRESENT);
-       else
-               *pme = make_pme(PM_NOT_PRESENT(pm->v2)                  |
-                               PM_STATUS2(pm->v2, flags2));
+       u64 frame = 0;
+
+       if (pte_present(pte)) {
+               frame = pte_pfn(pte) + offset;
+               flags |= PM_PRESENT;
+       }
+
+       return make_pme(frame, flags);
 }
 
 /* This function walks within one hugetlb entry in the single call */
@@ -1178,17 +1139,15 @@ static int pagemap_hugetlb_range(pte_t *pte, unsigned 
long hmask,
        struct pagemapread *pm = walk->private;
        struct vm_area_struct *vma = walk->vma;
        int err = 0;
-       int flags2;
+       u64 flags = 0;
        pagemap_entry_t pme;
 
        if (vma->vm_flags & VM_SOFTDIRTY)
-               flags2 = __PM_SOFT_DIRTY;
-       else
-               flags2 = 0;
+               flags |= PM_SOFT_DIRTY;
 
        for (; addr != end; addr += PAGE_SIZE) {
                int offset = (addr & ~hmask) >> PAGE_SHIFT;
-               huge_pte_to_pagemap_entry(&pme, pm, *pte, offset, flags2);
+               pme = huge_pte_to_pagemap_entry(pm, *pte, offset, flags);
                err = add_to_pagemap(addr, &pme, pm);
                if (err)
                        return err;
@@ -1209,7 +1168,8 @@ static int pagemap_hugetlb_range(pte_t *pte, unsigned 
long hmask,
  * Bits 0-54  page frame number (PFN) if present
  * Bits 0-4   swap type if swapped
  * Bits 5-54  swap offset if swapped
- * Bits 55-60 page shift (page size = 1<<page shift)
+ * Bit  55    pte is soft-dirty (see Documentation/vm/soft-dirty.txt)
+ * Bits 56-60 zero
  * Bit  61    page is file-page or shared-anon
  * Bit  62    page swapped
  * Bit  63    page present
@@ -1248,7 +1208,6 @@ static ssize_t pagemap_read(struct file *file, char 
__user *buf,
        if (!count)
                goto out_mm;
 
-       pm.v2 = soft_dirty_cleared;
        pm.len = (PAGEMAP_WALK_SIZE >> PAGE_SHIFT);
        pm.buffer = kmalloc(pm.len * PM_ENTRY_BYTES, GFP_TEMPORARY);
        ret = -ENOMEM;
@@ -1321,9 +1280,6 @@ static int pagemap_open(struct inode *inode, struct file 
*file)
        /* do not disclose physical addresses: attack vector */
        if (!capable(CAP_SYS_ADMIN))
                return -EPERM;
-       pr_warn_once("Bits 55-60 of /proc/PID/pagemap entries are about "
-                       "to stop being page-shift some time soon. See the "
-                       "linux/Documentation/vm/pagemap.txt for details.\n");
 
        mm = proc_mem_open(inode, PTRACE_MODE_READ);
        if (IS_ERR(mm))
diff --git a/tools/vm/page-types.c b/tools/vm/page-types.c
index 8bdf16b8ba60..603ec916716b 100644
--- a/tools/vm/page-types.c
+++ b/tools/vm/page-types.c
@@ -57,23 +57,14 @@
  * pagemap kernel ABI bits
  */
 
-#define PM_ENTRY_BYTES      sizeof(uint64_t)
-#define PM_STATUS_BITS      3
-#define PM_STATUS_OFFSET    (64 - PM_STATUS_BITS)
-#define PM_STATUS_MASK      (((1LL << PM_STATUS_BITS) - 1) << PM_STATUS_OFFSET)
-#define PM_STATUS(nr)       (((nr) << PM_STATUS_OFFSET) & PM_STATUS_MASK)
-#define PM_PSHIFT_BITS      6
-#define PM_PSHIFT_OFFSET    (PM_STATUS_OFFSET - PM_PSHIFT_BITS)
-#define PM_PSHIFT_MASK      (((1LL << PM_PSHIFT_BITS) - 1) << PM_PSHIFT_OFFSET)
-#define __PM_PSHIFT(x)      (((uint64_t) (x) << PM_PSHIFT_OFFSET) & 
PM_PSHIFT_MASK)
-#define PM_PFRAME_MASK      ((1LL << PM_PSHIFT_OFFSET) - 1)
-#define PM_PFRAME(x)        ((x) & PM_PFRAME_MASK)
-
-#define __PM_SOFT_DIRTY      (1LL)
-#define PM_PRESENT          PM_STATUS(4LL)
-#define PM_SWAP             PM_STATUS(2LL)
-#define PM_SOFT_DIRTY       __PM_PSHIFT(__PM_SOFT_DIRTY)
-
+#define PM_ENTRY_BYTES         8
+#define PM_PFRAME_BITS         55
+#define PM_PFRAME_MASK         ((1LL << PM_PFRAME_BITS) - 1)
+#define PM_PFRAME(x)           ((x) & PM_PFRAME_MASK)
+#define PM_SOFT_DIRTY          (1ULL << 55)
+#define PM_FILE                        (1ULL << 61)
+#define PM_SWAP                        (1ULL << 62)
+#define PM_PRESENT             (1ULL << 63)
 
 /*
  * kernel page flags

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