From 102a0743326a03cd1a1202ceda21e175b7d3575c Mon Sep 17 00:00:00 2001
From: hc <hc@nodka.com>
Date: Tue, 20 Feb 2024 01:20:52 +0000
Subject: [PATCH] add new system file
---
kernel/mm/nommu.c | 261 ++++++++++++++++-----------------------------------
1 files changed, 84 insertions(+), 177 deletions(-)
diff --git a/kernel/mm/nommu.c b/kernel/mm/nommu.c
index 86e1da9..f8f7f0e 100644
--- a/kernel/mm/nommu.c
+++ b/kernel/mm/nommu.c
@@ -1,10 +1,11 @@
+// SPDX-License-Identifier: GPL-2.0-only
/*
* linux/mm/nommu.c
*
* Replacement code for mm functions to support CPU's that don't
* have any form of memory management unit (thus no virtual memory).
*
- * See Documentation/nommu-mmap.txt
+ * See Documentation/admin-guide/mm/nommu-mmap.rst
*
* Copyright (c) 2004-2008 David Howells <dhowells@redhat.com>
* Copyright (c) 2000-2003 David McCullough <davidm@snapgear.com>
@@ -107,96 +108,8 @@
* The ksize() function is only guaranteed to work for pointers
* returned by kmalloc(). So handle arbitrary pointers here.
*/
- return PAGE_SIZE << compound_order(page);
+ return page_size(page);
}
-
-static long __get_user_pages(struct task_struct *tsk, struct mm_struct *mm,
- unsigned long start, unsigned long nr_pages,
- unsigned int foll_flags, struct page **pages,
- struct vm_area_struct **vmas, int *nonblocking)
-{
- struct vm_area_struct *vma;
- unsigned long vm_flags;
- int i;
-
- /* calculate required read or write permissions.
- * If FOLL_FORCE is set, we only require the "MAY" flags.
- */
- vm_flags = (foll_flags & FOLL_WRITE) ?
- (VM_WRITE | VM_MAYWRITE) : (VM_READ | VM_MAYREAD);
- vm_flags &= (foll_flags & FOLL_FORCE) ?
- (VM_MAYREAD | VM_MAYWRITE) : (VM_READ | VM_WRITE);
-
- for (i = 0; i < nr_pages; i++) {
- vma = find_vma(mm, start);
- if (!vma)
- goto finish_or_fault;
-
- /* protect what we can, including chardevs */
- if ((vma->vm_flags & (VM_IO | VM_PFNMAP)) ||
- !(vm_flags & vma->vm_flags))
- goto finish_or_fault;
-
- if (pages) {
- pages[i] = virt_to_page(start);
- if (pages[i])
- get_page(pages[i]);
- }
- if (vmas)
- vmas[i] = vma;
- start = (start + PAGE_SIZE) & PAGE_MASK;
- }
-
- return i;
-
-finish_or_fault:
- return i ? : -EFAULT;
-}
-
-/*
- * get a list of pages in an address range belonging to the specified process
- * and indicate the VMA that covers each page
- * - this is potentially dodgy as we may end incrementing the page count of a
- * slab page or a secondary page from a compound page
- * - don't permit access to VMAs that don't support it, such as I/O mappings
- */
-long get_user_pages(unsigned long start, unsigned long nr_pages,
- unsigned int gup_flags, struct page **pages,
- struct vm_area_struct **vmas)
-{
- return __get_user_pages(current, current->mm, start, nr_pages,
- gup_flags, pages, vmas, NULL);
-}
-EXPORT_SYMBOL(get_user_pages);
-
-long get_user_pages_locked(unsigned long start, unsigned long nr_pages,
- unsigned int gup_flags, struct page **pages,
- int *locked)
-{
- return get_user_pages(start, nr_pages, gup_flags, pages, NULL);
-}
-EXPORT_SYMBOL(get_user_pages_locked);
-
-static long __get_user_pages_unlocked(struct task_struct *tsk,
- struct mm_struct *mm, unsigned long start,
- unsigned long nr_pages, struct page **pages,
- unsigned int gup_flags)
-{
- long ret;
- down_read(&mm->mmap_sem);
- ret = __get_user_pages(tsk, mm, start, nr_pages, gup_flags, pages,
- NULL, NULL);
- up_read(&mm->mmap_sem);
- return ret;
-}
-
-long get_user_pages_unlocked(unsigned long start, unsigned long nr_pages,
- struct page **pages, unsigned int gup_flags)
-{
- return __get_user_pages_unlocked(current, current->mm, start, nr_pages,
- pages, gup_flags);
-}
-EXPORT_SYMBOL(get_user_pages_unlocked);
/**
* follow_pfn - look up PFN at a user virtual address
@@ -227,7 +140,7 @@
}
EXPORT_SYMBOL(vfree);
-void *__vmalloc(unsigned long size, gfp_t gfp_mask, pgprot_t prot)
+void *__vmalloc(unsigned long size, gfp_t gfp_mask)
{
/*
* You can't specify __GFP_HIGHMEM with kmalloc() since kmalloc()
@@ -237,27 +150,41 @@
}
EXPORT_SYMBOL(__vmalloc);
-void *__vmalloc_node_flags(unsigned long size, int node, gfp_t flags)
+void *__vmalloc_node_range(unsigned long size, unsigned long align,
+ unsigned long start, unsigned long end, gfp_t gfp_mask,
+ pgprot_t prot, unsigned long vm_flags, int node,
+ const void *caller)
{
- return __vmalloc(size, flags, PAGE_KERNEL);
+ return __vmalloc(size, gfp_mask);
+}
+
+void *__vmalloc_node(unsigned long size, unsigned long align, gfp_t gfp_mask,
+ int node, const void *caller)
+{
+ return __vmalloc(size, gfp_mask);
+}
+
+static void *__vmalloc_user_flags(unsigned long size, gfp_t flags)
+{
+ void *ret;
+
+ ret = __vmalloc(size, flags);
+ if (ret) {
+ struct vm_area_struct *vma;
+
+ mmap_write_lock(current->mm);
+ vma = find_vma(current->mm, (unsigned long)ret);
+ if (vma)
+ vma->vm_flags |= VM_USERMAP;
+ mmap_write_unlock(current->mm);
+ }
+
+ return ret;
}
void *vmalloc_user(unsigned long size)
{
- void *ret;
-
- ret = __vmalloc(size, GFP_KERNEL | __GFP_ZERO, PAGE_KERNEL);
- if (ret) {
- struct vm_area_struct *vma;
-
- down_write(¤t->mm->mmap_sem);
- vma = find_vma(current->mm, (unsigned long)ret);
- if (vma)
- vma->vm_flags |= VM_USERMAP;
- up_write(¤t->mm->mmap_sem);
- }
-
- return ret;
+ return __vmalloc_user_flags(size, GFP_KERNEL | __GFP_ZERO);
}
EXPORT_SYMBOL(vmalloc_user);
@@ -306,7 +233,7 @@
*/
void *vmalloc(unsigned long size)
{
- return __vmalloc(size, GFP_KERNEL | __GFP_HIGHMEM, PAGE_KERNEL);
+ return __vmalloc(size, GFP_KERNEL | __GFP_HIGHMEM);
}
EXPORT_SYMBOL(vmalloc);
@@ -324,8 +251,7 @@
*/
void *vzalloc(unsigned long size)
{
- return __vmalloc(size, GFP_KERNEL | __GFP_HIGHMEM | __GFP_ZERO,
- PAGE_KERNEL);
+ return __vmalloc(size, GFP_KERNEL | __GFP_HIGHMEM | __GFP_ZERO);
}
EXPORT_SYMBOL(vzalloc);
@@ -365,23 +291,6 @@
EXPORT_SYMBOL(vzalloc_node);
/**
- * vmalloc_exec - allocate virtually contiguous, executable memory
- * @size: allocation size
- *
- * Kernel-internal function to allocate enough pages to cover @size
- * the page level allocator and map them into contiguous and
- * executable kernel virtual space.
- *
- * For tight control over page level allocator and protection flags
- * use __vmalloc() instead.
- */
-
-void *vmalloc_exec(unsigned long size)
-{
- return __vmalloc(size, GFP_KERNEL | __GFP_HIGHMEM, PAGE_KERNEL_EXEC);
-}
-
-/**
* vmalloc_32 - allocate virtually contiguous memory (32bit addressable)
* @size: allocation size
*
@@ -390,7 +299,7 @@
*/
void *vmalloc_32(unsigned long size)
{
- return __vmalloc(size, GFP_KERNEL, PAGE_KERNEL);
+ return __vmalloc(size, GFP_KERNEL);
}
EXPORT_SYMBOL(vmalloc_32);
@@ -427,7 +336,7 @@
}
EXPORT_SYMBOL(vunmap);
-void *vm_map_ram(struct page **pages, unsigned int count, int node, pgprot_t prot)
+void *vm_map_ram(struct page **pages, unsigned int count, int node)
{
BUG();
return NULL;
@@ -445,25 +354,6 @@
}
EXPORT_SYMBOL_GPL(vm_unmap_aliases);
-/*
- * Implement a stub for vmalloc_sync_[un]mapping() if the architecture
- * chose not to have one.
- */
-void __weak vmalloc_sync_mappings(void)
-{
-}
-
-void __weak vmalloc_sync_unmappings(void)
-{
-}
-
-struct vm_struct *alloc_vm_area(size_t size, pte_t **ptes)
-{
- BUG();
- return NULL;
-}
-EXPORT_SYMBOL_GPL(alloc_vm_area);
-
void free_vm_area(struct vm_struct *area)
{
BUG();
@@ -476,6 +366,20 @@
return -EINVAL;
}
EXPORT_SYMBOL(vm_insert_page);
+
+int vm_map_pages(struct vm_area_struct *vma, struct page **pages,
+ unsigned long num)
+{
+ return -EINVAL;
+}
+EXPORT_SYMBOL(vm_map_pages);
+
+int vm_map_pages_zero(struct vm_area_struct *vma, struct page **pages,
+ unsigned long num)
+{
+ return -EINVAL;
+}
+EXPORT_SYMBOL(vm_map_pages_zero);
/*
* sys_brk() for the most part doesn't need the global kernel
@@ -505,7 +409,7 @@
/*
* Ok, looks good - let it rip.
*/
- flush_icache_range(mm->brk, brk);
+ flush_icache_user_range(mm->brk, brk);
return mm->brk = brk;
}
@@ -654,7 +558,7 @@
* add a VMA into a process's mm_struct in the appropriate place in the list
* and tree and add to the address space's page tree also if not an anonymous
* page
- * - should be called with mm->mmap_sem held writelocked
+ * - should be called with mm->mmap_lock held writelocked
*/
static void add_vma_to_mm(struct mm_struct *mm, struct vm_area_struct *vma)
{
@@ -714,7 +618,7 @@
if (rb_prev)
prev = rb_entry(rb_prev, struct vm_area_struct, vm_rb);
- __vma_link_list(mm, vma, prev, parent);
+ __vma_link_list(mm, vma, prev);
}
/*
@@ -750,13 +654,7 @@
/* remove from the MM's tree and list */
rb_erase(&vma->vm_rb, &mm->mm_rb);
- if (vma->vm_prev)
- vma->vm_prev->vm_next = vma->vm_next;
- else
- mm->mmap = vma->vm_next;
-
- if (vma->vm_next)
- vma->vm_next->vm_prev = vma->vm_prev;
+ __vma_unlink_list(mm, vma);
}
/*
@@ -774,7 +672,7 @@
/*
* look up the first VMA in which addr resides, NULL if none
- * - should be called with mm->mmap_sem at least held readlocked
+ * - should be called with mm->mmap_lock at least held readlocked
*/
struct vm_area_struct *find_vma(struct mm_struct *mm, unsigned long addr)
{
@@ -820,7 +718,7 @@
/*
* look up the first VMA exactly that exactly matches addr
- * - should be called with mm->mmap_sem at least held readlocked
+ * - should be called with mm->mmap_lock at least held readlocked
*/
static struct vm_area_struct *find_vma_exact(struct mm_struct *mm,
unsigned long addr,
@@ -1173,7 +1071,6 @@
unsigned long len,
unsigned long prot,
unsigned long flags,
- vm_flags_t vm_flags,
unsigned long pgoff,
unsigned long *populate,
struct list_head *uf)
@@ -1181,6 +1078,7 @@
struct vm_area_struct *vma;
struct vm_region *region;
struct rb_node *rb;
+ vm_flags_t vm_flags;
unsigned long capabilities, result;
int ret;
@@ -1199,7 +1097,7 @@
/* we've determined that we can make the mapping, now translate what we
* now know into VMA flags */
- vm_flags |= determine_vm_flags(file, prot, flags, capabilities);
+ vm_flags = determine_vm_flags(file, prot, flags, capabilities);
/* we're going to need to record the mapping */
region = kmem_cache_zalloc(vm_region_jar, GFP_KERNEL);
@@ -1338,7 +1236,9 @@
add_nommu_region(region);
/* clear anonymous mappings that don't ask for uninitialized data */
- if (!vma->vm_file && !(flags & MAP_UNINITIALIZED))
+ if (!vma->vm_file &&
+ (!IS_ENABLED(CONFIG_MMAP_ALLOW_UNINITIALIZED) ||
+ !(flags & MAP_UNINITIALIZED)))
memset((void *)region->vm_start, 0,
region->vm_end - region->vm_start);
@@ -1353,7 +1253,7 @@
/* we flush the region from the icache only when the first executable
* mapping of it is made */
if (vma->vm_flags & VM_EXEC && !region->vm_icache_flushed) {
- flush_icache_range(region->vm_start, region->vm_end);
+ flush_icache_user_range(region->vm_start, region->vm_end);
region->vm_icache_flushed = true;
}
@@ -1618,9 +1518,9 @@
struct mm_struct *mm = current->mm;
int ret;
- down_write(&mm->mmap_sem);
+ mmap_write_lock(mm);
ret = do_munmap(mm, addr, len, NULL);
- up_write(&mm->mmap_sem);
+ mmap_write_unlock(mm);
return ret;
}
EXPORT_SYMBOL(vm_munmap);
@@ -1707,17 +1607,15 @@
{
unsigned long ret;
- down_write(¤t->mm->mmap_sem);
+ mmap_write_lock(current->mm);
ret = do_mremap(addr, old_len, new_len, flags, new_addr);
- up_write(¤t->mm->mmap_sem);
+ mmap_write_unlock(current->mm);
return ret;
}
-struct page *follow_page_mask(struct vm_area_struct *vma,
- unsigned long address, unsigned int flags,
- unsigned int *page_mask)
+struct page *follow_page(struct vm_area_struct *vma, unsigned long address,
+ unsigned int foll_flags)
{
- *page_mask = 0;
return NULL;
}
@@ -1770,12 +1668,21 @@
}
EXPORT_SYMBOL(filemap_fault);
-void filemap_map_pages(struct vm_fault *vmf,
+vm_fault_t filemap_map_pages(struct vm_fault *vmf,
pgoff_t start_pgoff, pgoff_t end_pgoff)
{
BUG();
+ return 0;
}
EXPORT_SYMBOL(filemap_map_pages);
+
+#ifdef CONFIG_SPECULATIVE_PAGE_FAULT
+bool filemap_allow_speculation(void)
+{
+ BUG();
+ return false;
+}
+#endif
int __access_remote_vm(struct task_struct *tsk, struct mm_struct *mm,
unsigned long addr, void *buf, int len, unsigned int gup_flags)
@@ -1783,7 +1690,7 @@
struct vm_area_struct *vma;
int write = gup_flags & FOLL_WRITE;
- if (down_read_killable(&mm->mmap_sem))
+ if (mmap_read_lock_killable(mm))
return 0;
/* the access must start within one of the target process's mappings */
@@ -1806,7 +1713,7 @@
len = 0;
}
- up_read(&mm->mmap_sem);
+ mmap_read_unlock(mm);
return len;
}
@@ -1857,8 +1764,8 @@
* @newsize: The proposed filesize of the inode
*
* Check the shared mappings on an inode on behalf of a shrinking truncate to
- * make sure that that any outstanding VMAs aren't broken and then shrink the
- * vm_regions that extend that beyond so that do_mmap_pgoff() doesn't
+ * make sure that any outstanding VMAs aren't broken and then shrink the
+ * vm_regions that extend beyond so that do_mmap() doesn't
* automatically grant mappings that are too large.
*/
int nommu_shrink_inode_mappings(struct inode *inode, size_t size,
--
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