#include <linux/list.h>
#include <linux/hashtable.h>
-#include <linux/sched.h>
+#include <linux/sched/signal.h>
+#include <linux/sched/mm.h>
#include <linux/mm.h>
#include <linux/poll.h>
#include <linux/slab.h>
struct list_head list;
};
+struct userfaultfd_unmap_ctx {
+ struct userfaultfd_ctx *ctx;
+ unsigned long start;
+ unsigned long end;
+ struct list_head list;
+};
+
struct userfaultfd_wait_queue {
struct uffd_msg msg;
wait_queue_t wq;
* userfaultfd_ctx_get - Acquires a reference to the internal userfaultfd
* context.
* @ctx: [in] Pointer to the userfaultfd context.
- *
- * Returns: In case of success, returns not zero.
*/
static void userfaultfd_ctx_get(struct userfaultfd_ctx *ctx)
{
{
struct mm_struct *mm = ctx->mm;
pgd_t *pgd;
+ p4d_t *p4d;
pud_t *pud;
pmd_t *pmd, _pmd;
pte_t *pte;
pgd = pgd_offset(mm, address);
if (!pgd_present(*pgd))
goto out;
- pud = pud_offset(pgd, address);
+ p4d = p4d_offset(pgd, address);
+ if (!p4d_present(*p4d))
+ goto out;
+ pud = pud_offset(p4d, address);
if (!pud_present(*pud))
goto out;
pmd = pmd_offset(pud, address);
* in such case.
*/
down_read(&mm->mmap_sem);
- ret = 0;
+ ret = VM_FAULT_NOPAGE;
}
}
return ret;
}
-static int userfaultfd_event_wait_completion(struct userfaultfd_ctx *ctx,
- struct userfaultfd_wait_queue *ewq)
+static void userfaultfd_event_wait_completion(struct userfaultfd_ctx *ctx,
+ struct userfaultfd_wait_queue *ewq)
{
- int ret = 0;
+ if (WARN_ON_ONCE(current->flags & PF_EXITING))
+ goto out;
ewq->ctx = ctx;
init_waitqueue_entry(&ewq->wq, current);
break;
if (ACCESS_ONCE(ctx->released) ||
fatal_signal_pending(current)) {
- ret = -1;
__remove_wait_queue(&ctx->event_wqh, &ewq->wq);
+ if (ewq->msg.event == UFFD_EVENT_FORK) {
+ struct userfaultfd_ctx *new;
+
+ new = (struct userfaultfd_ctx *)
+ (unsigned long)
+ ewq->msg.arg.reserved.reserved1;
+
+ userfaultfd_ctx_put(new);
+ }
break;
}
* ctx may go away after this if the userfault pseudo fd is
* already released.
*/
-
+out:
userfaultfd_ctx_put(ctx);
- return ret;
}
static void userfaultfd_event_complete(struct userfaultfd_ctx *ctx,
return 0;
}
-static int dup_fctx(struct userfaultfd_fork_ctx *fctx)
+static void dup_fctx(struct userfaultfd_fork_ctx *fctx)
{
struct userfaultfd_ctx *ctx = fctx->orig;
struct userfaultfd_wait_queue ewq;
ewq.msg.event = UFFD_EVENT_FORK;
ewq.msg.arg.reserved.reserved1 = (unsigned long)fctx->new;
- return userfaultfd_event_wait_completion(ctx, &ewq);
+ userfaultfd_event_wait_completion(ctx, &ewq);
}
void dup_userfaultfd_complete(struct list_head *fcs)
{
- int ret = 0;
struct userfaultfd_fork_ctx *fctx, *n;
list_for_each_entry_safe(fctx, n, fcs, list) {
- if (!ret)
- ret = dup_fctx(fctx);
+ dup_fctx(fctx);
list_del(&fctx->list);
kfree(fctx);
}
userfaultfd_event_wait_completion(ctx, &ewq);
}
-void madvise_userfault_dontneed(struct vm_area_struct *vma,
- struct vm_area_struct **prev,
- unsigned long start, unsigned long end)
+bool userfaultfd_remove(struct vm_area_struct *vma,
+ unsigned long start, unsigned long end)
{
struct mm_struct *mm = vma->vm_mm;
struct userfaultfd_ctx *ctx;
struct userfaultfd_wait_queue ewq;
ctx = vma->vm_userfaultfd_ctx.ctx;
- if (!ctx || !(ctx->features & UFFD_FEATURE_EVENT_MADVDONTNEED))
- return;
+ if (!ctx || !(ctx->features & UFFD_FEATURE_EVENT_REMOVE))
+ return true;
userfaultfd_ctx_get(ctx);
up_read(&mm->mmap_sem);
- *prev = NULL; /* We wait for ACK w/o the mmap semaphore */
-
msg_init(&ewq.msg);
- ewq.msg.event = UFFD_EVENT_MADVDONTNEED;
- ewq.msg.arg.madv_dn.start = start;
- ewq.msg.arg.madv_dn.end = end;
+ ewq.msg.event = UFFD_EVENT_REMOVE;
+ ewq.msg.arg.remove.start = start;
+ ewq.msg.arg.remove.end = end;
userfaultfd_event_wait_completion(ctx, &ewq);
- down_read(&mm->mmap_sem);
+ return false;
+}
+
+static bool has_unmap_ctx(struct userfaultfd_ctx *ctx, struct list_head *unmaps,
+ unsigned long start, unsigned long end)
+{
+ struct userfaultfd_unmap_ctx *unmap_ctx;
+
+ list_for_each_entry(unmap_ctx, unmaps, list)
+ if (unmap_ctx->ctx == ctx && unmap_ctx->start == start &&
+ unmap_ctx->end == end)
+ return true;
+
+ return false;
+}
+
+int userfaultfd_unmap_prep(struct vm_area_struct *vma,
+ unsigned long start, unsigned long end,
+ struct list_head *unmaps)
+{
+ for ( ; vma && vma->vm_start < end; vma = vma->vm_next) {
+ struct userfaultfd_unmap_ctx *unmap_ctx;
+ struct userfaultfd_ctx *ctx = vma->vm_userfaultfd_ctx.ctx;
+
+ if (!ctx || !(ctx->features & UFFD_FEATURE_EVENT_UNMAP) ||
+ has_unmap_ctx(ctx, unmaps, start, end))
+ continue;
+
+ unmap_ctx = kzalloc(sizeof(*unmap_ctx), GFP_KERNEL);
+ if (!unmap_ctx)
+ return -ENOMEM;
+
+ userfaultfd_ctx_get(ctx);
+ unmap_ctx->ctx = ctx;
+ unmap_ctx->start = start;
+ unmap_ctx->end = end;
+ list_add_tail(&unmap_ctx->list, unmaps);
+ }
+
+ return 0;
+}
+
+void userfaultfd_unmap_complete(struct mm_struct *mm, struct list_head *uf)
+{
+ struct userfaultfd_unmap_ctx *ctx, *n;
+ struct userfaultfd_wait_queue ewq;
+
+ list_for_each_entry_safe(ctx, n, uf, list) {
+ msg_init(&ewq.msg);
+
+ ewq.msg.event = UFFD_EVENT_UNMAP;
+ ewq.msg.arg.remove.start = ctx->start;
+ ewq.msg.arg.remove.end = ctx->end;
+
+ userfaultfd_event_wait_completion(ctx->ctx, &ewq);
+
+ list_del(&ctx->list);
+ kfree(ctx);
+ }
}
static int userfaultfd_release(struct inode *inode, struct file *file)
ret = mcopy_atomic(ctx->mm, uffdio_copy.dst, uffdio_copy.src,
uffdio_copy.len);
mmput(ctx->mm);
+ } else {
+ return -ENOSPC;
}
if (unlikely(put_user(ret, &user_uffdio_copy->copy)))
return -EFAULT;
}
/**
- * userfaultfd_file_create - Creates an userfaultfd file pointer.
+ * userfaultfd_file_create - Creates a userfaultfd file pointer.
* @flags: Flags for the userfaultfd file.
*
- * This function creates an userfaultfd file pointer, w/out installing
+ * This function creates a userfaultfd file pointer, w/out installing
* it into the fd table. This is useful when the userfaultfd file is
* used during the initialization of data structures that require
* extra setup after the userfaultfd creation. So the userfaultfd
* creation is split into the file pointer creation phase, and the
* file descriptor installation phase. In this way races with
* userspace closing the newly installed file descriptor can be
- * avoided. Returns an userfaultfd file pointer, or a proper error
+ * avoided. Returns a userfaultfd file pointer, or a proper error
* pointer.
*/
static struct file *userfaultfd_file_create(int flags)
ctx->released = false;
ctx->mm = current->mm;
/* prevent the mm struct to be freed */
- atomic_inc(&ctx->mm->mm_count);
+ mmgrab(ctx->mm);
file = anon_inode_getfile("[userfaultfd]", &userfaultfd_fops, ctx,
O_RDWR | (flags & UFFD_SHARED_FCNTL_FLAGS));
projects / karo-tx-linux.git / blobdiff