summaryrefslogtreecommitdiff
path: root/mm/gup.c
diff options
context:
space:
mode:
Diffstat (limited to 'mm/gup.c')
-rw-r--r--mm/gup.c91
1 files changed, 70 insertions, 21 deletions
diff --git a/mm/gup.c b/mm/gup.c
index 7bf19ffa2..c057784c8 100644
--- a/mm/gup.c
+++ b/mm/gup.c
@@ -14,6 +14,7 @@
#include <linux/rwsem.h>
#include <linux/hugetlb.h>
+#include <asm/mmu_context.h>
#include <asm/pgtable.h>
#include <asm/tlbflush.h>
@@ -363,6 +364,8 @@ static int faultin_page(struct task_struct *tsk, struct vm_area_struct *vma,
return -ENOENT;
if (*flags & FOLL_WRITE)
fault_flags |= FAULT_FLAG_WRITE;
+ if (*flags & FOLL_REMOTE)
+ fault_flags |= FAULT_FLAG_REMOTE;
if (nonblocking)
fault_flags |= FAULT_FLAG_ALLOW_RETRY;
if (*flags & FOLL_NOWAIT)
@@ -413,11 +416,13 @@ static int faultin_page(struct task_struct *tsk, struct vm_area_struct *vma,
static int check_vma_flags(struct vm_area_struct *vma, unsigned long gup_flags)
{
vm_flags_t vm_flags = vma->vm_flags;
+ int write = (gup_flags & FOLL_WRITE);
+ int foreign = (gup_flags & FOLL_REMOTE);
if (vm_flags & (VM_IO | VM_PFNMAP))
return -EFAULT;
- if (gup_flags & FOLL_WRITE) {
+ if (write) {
if (!(vm_flags & VM_WRITE)) {
if (!(gup_flags & FOLL_FORCE))
return -EFAULT;
@@ -443,6 +448,12 @@ static int check_vma_flags(struct vm_area_struct *vma, unsigned long gup_flags)
if (!(vm_flags & VM_MAYREAD))
return -EFAULT;
}
+ /*
+ * gups are always data accesses, not instruction
+ * fetches, so execute=false here
+ */
+ if (!arch_vma_access_permitted(vma, write, false, foreign))
+ return -EFAULT;
return 0;
}
@@ -609,6 +620,28 @@ next_page:
}
EXPORT_SYMBOL(__get_user_pages);
+bool vma_permits_fault(struct vm_area_struct *vma, unsigned int fault_flags)
+{
+ bool write = !!(fault_flags & FAULT_FLAG_WRITE);
+ bool foreign = !!(fault_flags & FAULT_FLAG_REMOTE);
+ vm_flags_t vm_flags = write ? VM_WRITE : VM_READ;
+
+ if (!(vm_flags & vma->vm_flags))
+ return false;
+
+ /*
+ * The architecture might have a hardware protection
+ * mechanism other than read/write that can deny access.
+ *
+ * gup always represents data access, not instruction
+ * fetches, so execute=false here:
+ */
+ if (!arch_vma_access_permitted(vma, write, false, foreign))
+ return false;
+
+ return true;
+}
+
/*
* fixup_user_fault() - manually resolve a user page fault
* @tsk: the task_struct to use for page fault accounting, or
@@ -644,7 +677,6 @@ int fixup_user_fault(struct task_struct *tsk, struct mm_struct *mm,
bool *unlocked)
{
struct vm_area_struct *vma;
- vm_flags_t vm_flags;
int ret, major = 0;
if (unlocked)
@@ -655,8 +687,7 @@ retry:
if (!vma || address < vma->vm_start)
return -EFAULT;
- vm_flags = (fault_flags & FAULT_FLAG_WRITE) ? VM_WRITE : VM_READ;
- if (!(vm_flags & vma->vm_flags))
+ if (!vma_permits_fault(vma, fault_flags))
return -EFAULT;
ret = handle_mm_fault(mm, vma, address, fault_flags);
@@ -807,13 +838,13 @@ static __always_inline long __get_user_pages_locked(struct task_struct *tsk,
* if (locked)
* up_read(&mm->mmap_sem);
*/
-long get_user_pages_locked(struct task_struct *tsk, struct mm_struct *mm,
- unsigned long start, unsigned long nr_pages,
+long get_user_pages_locked(unsigned long start, unsigned long nr_pages,
int write, int force, struct page **pages,
int *locked)
{
- return __get_user_pages_locked(tsk, mm, start, nr_pages, write, force,
- pages, NULL, locked, true, FOLL_TOUCH);
+ return __get_user_pages_locked(current, current->mm, start, nr_pages,
+ write, force, pages, NULL, locked, true,
+ FOLL_TOUCH);
}
EXPORT_SYMBOL(get_user_pages_locked);
@@ -860,17 +891,16 @@ EXPORT_SYMBOL(__get_user_pages_unlocked);
* or if "force" shall be set to 1 (get_user_pages_fast misses the
* "force" parameter).
*/
-long get_user_pages_unlocked(struct task_struct *tsk, struct mm_struct *mm,
- unsigned long start, unsigned long nr_pages,
+long get_user_pages_unlocked(unsigned long start, unsigned long nr_pages,
int write, int force, struct page **pages)
{
- return __get_user_pages_unlocked(tsk, mm, start, nr_pages, write,
- force, pages, FOLL_TOUCH);
+ return __get_user_pages_unlocked(current, current->mm, start, nr_pages,
+ write, force, pages, FOLL_TOUCH);
}
EXPORT_SYMBOL(get_user_pages_unlocked);
/*
- * get_user_pages() - pin user pages in memory
+ * get_user_pages_remote() - pin user pages in memory
* @tsk: the task_struct to use for page fault accounting, or
* NULL if faults are not to be recorded.
* @mm: mm_struct of target mm
@@ -924,12 +954,30 @@ EXPORT_SYMBOL(get_user_pages_unlocked);
* should use get_user_pages because it cannot pass
* FAULT_FLAG_ALLOW_RETRY to handle_mm_fault.
*/
-long get_user_pages(struct task_struct *tsk, struct mm_struct *mm,
- unsigned long start, unsigned long nr_pages, int write,
- int force, struct page **pages, struct vm_area_struct **vmas)
+long get_user_pages_remote(struct task_struct *tsk, struct mm_struct *mm,
+ unsigned long start, unsigned long nr_pages,
+ int write, int force, struct page **pages,
+ struct vm_area_struct **vmas)
{
return __get_user_pages_locked(tsk, mm, start, nr_pages, write, force,
- pages, vmas, NULL, false, FOLL_TOUCH);
+ pages, vmas, NULL, false,
+ FOLL_TOUCH | FOLL_REMOTE);
+}
+EXPORT_SYMBOL(get_user_pages_remote);
+
+/*
+ * This is the same as get_user_pages_remote(), just with a
+ * less-flexible calling convention where we assume that the task
+ * and mm being operated on are the current task's. We also
+ * obviously don't pass FOLL_REMOTE in here.
+ */
+long get_user_pages(unsigned long start, unsigned long nr_pages,
+ int write, int force, struct page **pages,
+ struct vm_area_struct **vmas)
+{
+ return __get_user_pages_locked(current, current->mm, start, nr_pages,
+ write, force, pages, vmas, NULL, false,
+ FOLL_TOUCH);
}
EXPORT_SYMBOL(get_user_pages);
@@ -1058,7 +1106,7 @@ int __mm_populate(unsigned long start, unsigned long len, int ignore_errors)
* @addr: user address
*
* Returns struct page pointer of user page pinned for dump,
- * to be freed afterwards by page_cache_release() or put_page().
+ * to be freed afterwards by put_page().
*
* Returns NULL on any kind of failure - a hole must then be inserted into
* the corefile, to preserve alignment with its headers; and also returns
@@ -1144,6 +1192,9 @@ static int gup_pte_range(pmd_t pmd, unsigned long addr, unsigned long end,
pte_protnone(pte) || (write && !pte_write(pte)))
goto pte_unmap;
+ if (!arch_pte_access_permitted(pte, write))
+ goto pte_unmap;
+
VM_BUG_ON(!pfn_valid(pte_pfn(pte)));
page = pte_page(pte);
head = compound_head(page);
@@ -1439,7 +1490,6 @@ int __get_user_pages_fast(unsigned long start, int nr_pages, int write,
int get_user_pages_fast(unsigned long start, int nr_pages, int write,
struct page **pages)
{
- struct mm_struct *mm = current->mm;
int nr, ret;
start &= PAGE_MASK;
@@ -1451,8 +1501,7 @@ int get_user_pages_fast(unsigned long start, int nr_pages, int write,
start += nr << PAGE_SHIFT;
pages += nr;
- ret = get_user_pages_unlocked(current, mm, start,
- nr_pages - nr, write, 0, pages);
+ ret = get_user_pages_unlocked(start, nr_pages - nr, write, 0, pages);
/* Have to be a bit careful with return values */
if (nr > 0) {
generated by cgit v1.2.3-54-g00ecf (git 2.45.2) at 2024-11-11 16:35:57 +0000