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6.6: Add patches for WRITE_WATCH support in Wine (#857)
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This adds missing write watch patches I've ported over from 6.1 to 6.6.
I'm using this in my own daily-drive 6.6 LTS kernel.

See-also: kakra/linux#30
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@kakra
kakra authored Dec 11, 2023
1 parent 9a4b780 commit 112adb9
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248 changes: 248 additions & 0 deletions linux-tkg-patches/6.6/0001-mm-Support-soft-dirty-flag-reset-for-VA-range.patch
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Original file line number Diff line number Diff line change
@@ -0,0 +1,248 @@
From 23d7461352e269625f418ff525de2451fbfaef54 Mon Sep 17 00:00:00 2001
From: Paul Gofman <pgofman@codeweavers.com>
Date: Wed, 6 May 2020 14:37:44 +0300
Subject: [PATCH 1/2] mm: Support soft dirty flag reset for VA range.

v2: ported from 6.1 to 6.6

Signed-off-by: Kai Krakow <kai@kaishome.de>
---
fs/proc/task_mmu.c | 129 ++++++++++++++++++++++++++++++++++++---------
1 file changed, 103 insertions(+), 26 deletions(-)

diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c
index 3dd5be96691b4..daa4fc32de9a2 100644
--- a/fs/proc/task_mmu.c
+++ b/fs/proc/task_mmu.c
@@ -1072,6 +1072,8 @@ enum clear_refs_types {

struct clear_refs_private {
enum clear_refs_types type;
+ unsigned long start, end;
+ bool clear_range;
};

#ifdef CONFIG_MEM_SOFT_DIRTY
@@ -1163,6 +1165,8 @@ static int clear_refs_pte_range(pmd_t *pmd, unsigned long addr,
spinlock_t *ptl;
struct page *page;

+ BUG_ON(addr < cp->start || end > cp->end);
+
ptl = pmd_trans_huge_lock(pmd, vma);
if (ptl) {
if (cp->type == CLEAR_REFS_SOFT_DIRTY) {
@@ -1220,9 +1224,11 @@ static int clear_refs_test_walk(unsigned long start, unsigned long end,
struct clear_refs_private *cp = walk->private;
struct vm_area_struct *vma = walk->vma;

- if (vma->vm_flags & VM_PFNMAP)
+ if (!cp->clear_range && (vma->vm_flags & VM_PFNMAP))
return 1;

+ BUG_ON(start < cp->start || end > cp->end);
+
/*
* Writing 1 to /proc/pid/clear_refs affects all pages.
* Writing 2 to /proc/pid/clear_refs only affects anonymous pages.
@@ -1246,10 +1252,12 @@ static ssize_t clear_refs_write(struct file *file, const char __user *buf,
size_t count, loff_t *ppos)
{
struct task_struct *task;
- char buffer[PROC_NUMBUF];
+ char buffer[18];
struct mm_struct *mm;
struct vm_area_struct *vma;
enum clear_refs_types type;
+ unsigned long start, end;
+ bool clear_range;
int itype;
int rv;

@@ -1258,12 +1266,34 @@ static ssize_t clear_refs_write(struct file *file, const char __user *buf,
count = sizeof(buffer) - 1;
if (copy_from_user(buffer, buf, count))
return -EFAULT;
- rv = kstrtoint(strstrip(buffer), 10, &itype);
- if (rv < 0)
- return rv;
- type = (enum clear_refs_types)itype;
- if (type < CLEAR_REFS_ALL || type >= CLEAR_REFS_LAST)
- return -EINVAL;
+
+ if (buffer[0] == '6')
+ {
+ static int once;
+
+ if (!once++)
+ printk(KERN_DEBUG "task_mmu: Using POC clear refs range implementation.\n");
+
+ if (count != 17)
+ return -EINVAL;
+
+ type = CLEAR_REFS_SOFT_DIRTY;
+ start = *(unsigned long *)(buffer + 1);
+ end = *(unsigned long *)(buffer + 1 + 8);
+ }
+ else
+ {
+ rv = kstrtoint(strstrip(buffer), 10, &itype);
+ if (rv < 0)
+ return rv;
+ type = (enum clear_refs_types)itype;
+
+ if (type < CLEAR_REFS_ALL || type >= CLEAR_REFS_LAST)
+ return -EINVAL;
+
+ start = 0;
+ end = -1UL;
+ }

task = get_proc_task(file_inode(file));
if (!task)
@@ -1276,40 +1306,86 @@ static ssize_t clear_refs_write(struct file *file, const char __user *buf,
.type = type,
};

- if (mmap_write_lock_killable(mm)) {
- count = -EINTR;
- goto out_mm;
+ if (start || end != -1UL)
+ {
+ start = min(start, -1UL) & PAGE_MASK;
+ end = min(end, -1UL) & PAGE_MASK;
+
+ if (start >= end)
+ {
+ count = -EINVAL;
+ goto out_mm;
+ }
+ clear_range = true;
}
+ else
+ {
+ clear_range = false;
+ }
+
+ cp.start = start;
+ cp.end = end;
+ cp.clear_range = clear_range;
+
if (type == CLEAR_REFS_MM_HIWATER_RSS) {
+ if (mmap_write_lock_killable(mm)) {
+ count = -EINTR;
+ goto out_mm;
+ }
+
/*
* Writing 5 to /proc/pid/clear_refs resets the peak
* resident set size to this mm's current rss value.
*/
reset_mm_hiwater_rss(mm);
- goto out_unlock;
+ mmap_write_unlock(mm);
+ goto out_mm;
}

if (type == CLEAR_REFS_SOFT_DIRTY) {
- for_each_vma(vmi, vma) {
- if (!(vma->vm_flags & VM_SOFTDIRTY))
- continue;
- vm_flags_clear(vma, VM_SOFTDIRTY);
- vma_set_page_prot(vma);
+ if (mmap_read_lock_killable(mm)) {
+ count = -EINTR;
+ goto out_mm;
}
-
+ if (!clear_range)
+ for_each_vma(vmi, vma) {
+ if (!(vma->vm_flags & VM_SOFTDIRTY))
+ continue;
+ mmap_read_unlock(mm);
+ if (mmap_write_lock_killable(mm)) {
+ count = -EINTR;
+ goto out_mm;
+ }
+ for_each_vma(vmi, vma) {
+ vm_flags_clear(vma, VM_SOFTDIRTY);
+ vma_set_page_prot(vma);
+ }
+ mmap_write_downgrade(mm);
+ break;
+ }
inc_tlb_flush_pending(mm);
mmu_notifier_range_init(&range, MMU_NOTIFY_SOFT_DIRTY,
- 0, mm, 0, -1UL);
+ 0, mm, start, end);
mmu_notifier_invalidate_range_start(&range);
}
- walk_page_range(mm, 0, -1, &clear_refs_walk_ops, &cp);
+ else
+ {
+ if (mmap_write_lock_killable(mm)) {
+ count = -EINTR;
+ goto out_mm;
+ }
+ }
+ walk_page_range(mm, start, end == -1UL ? -1 : end, &clear_refs_walk_ops, &cp);
if (type == CLEAR_REFS_SOFT_DIRTY) {
mmu_notifier_invalidate_range_end(&range);
flush_tlb_mm(mm);
dec_tlb_flush_pending(mm);
+ mmap_read_unlock(mm);
+ }
+ else
+ {
+ mmap_write_unlock(mm);
}
-out_unlock:
- mmap_write_unlock(mm);
out_mm:
mmput(mm);
}
@@ -1341,6 +1417,7 @@ struct pagemapread {
#define PM_PFRAME_MASK GENMASK_ULL(PM_PFRAME_BITS - 1, 0)
#define PM_SOFT_DIRTY BIT_ULL(55)
#define PM_MMAP_EXCLUSIVE BIT_ULL(56)
+#define PM_SOFT_DIRTY_PAGE BIT_ULL(57)
#define PM_UFFD_WP BIT_ULL(57)
#define PM_FILE BIT_ULL(61)
#define PM_SWAP BIT_ULL(62)
@@ -1415,13 +1492,13 @@ static pagemap_entry_t pte_to_pagemap_entry(struct pagemapread *pm,
flags |= PM_PRESENT;
page = vm_normal_page(vma, addr, pte);
if (pte_soft_dirty(pte))
- flags |= PM_SOFT_DIRTY;
+ flags |= PM_SOFT_DIRTY | PM_SOFT_DIRTY_PAGE;
if (pte_uffd_wp(pte))
flags |= PM_UFFD_WP;
} else if (is_swap_pte(pte)) {
swp_entry_t entry;
if (pte_swp_soft_dirty(pte))
- flags |= PM_SOFT_DIRTY;
+ flags |= PM_SOFT_DIRTY | PM_SOFT_DIRTY_PAGE;
if (pte_swp_uffd_wp(pte))
flags |= PM_UFFD_WP;
entry = pte_to_swp_entry(pte);
@@ -1481,7 +1558,7 @@ static int pagemap_pmd_range(pmd_t *pmdp, unsigned long addr, unsigned long end,

flags |= PM_PRESENT;
if (pmd_soft_dirty(pmd))
- flags |= PM_SOFT_DIRTY;
+ flags |= PM_SOFT_DIRTY | PM_SOFT_DIRTY_PAGE;
if (pmd_uffd_wp(pmd))
flags |= PM_UFFD_WP;
if (pm->show_pfn)
@@ -1505,7 +1582,7 @@ static int pagemap_pmd_range(pmd_t *pmdp, unsigned long addr, unsigned long end,
}
flags |= PM_SWAP;
if (pmd_swp_soft_dirty(pmd))
- flags |= PM_SOFT_DIRTY;
+ flags |= PM_SOFT_DIRTY | PM_SOFT_DIRTY_PAGE;
if (pmd_swp_uffd_wp(pmd))
flags |= PM_UFFD_WP;
VM_BUG_ON(!is_pmd_migration_entry(pmd));
--
2.41.0

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