#include <linux/sched/signal.h>
#include <linux/sched/mm.h>
#include <linux/mm.h>
+#include <linux/mmu_notifier.h>
#include <linux/poll.h>
#include <linux/slab.h>
#include <linux/seq_file.h>
msg_init(&msg);
msg.event = UFFD_EVENT_PAGEFAULT;
msg.arg.pagefault.address = address;
+ /*
+ * These flags indicate why the userfault occurred:
+ * - UFFD_PAGEFAULT_FLAG_WP indicates a write protect fault.
+ * - UFFD_PAGEFAULT_FLAG_MINOR indicates a minor fault.
+ * - Neither of these flags being set indicates a MISSING fault.
+ *
+ * Separately, UFFD_PAGEFAULT_FLAG_WRITE indicates it was a write
+ * fault. Otherwise, it was a read fault.
+ */
if (flags & FAULT_FLAG_WRITE)
- /*
- * If UFFD_FEATURE_PAGEFAULT_FLAG_WP was set in the
- * uffdio_api.features and UFFD_PAGEFAULT_FLAG_WRITE
- * was not set in a UFFD_EVENT_PAGEFAULT, it means it
- * was a read fault, otherwise if set it means it's
- * a write fault.
- */
msg.arg.pagefault.flags |= UFFD_PAGEFAULT_FLAG_WRITE;
if (reason & VM_UFFD_WP)
- /*
- * If UFFD_FEATURE_PAGEFAULT_FLAG_WP was set in the
- * uffdio_api.features and UFFD_PAGEFAULT_FLAG_WP was
- * not set in a UFFD_EVENT_PAGEFAULT, it means it was
- * a missing fault, otherwise if set it means it's a
- * write protect fault.
- */
msg.arg.pagefault.flags |= UFFD_PAGEFAULT_FLAG_WP;
+ if (reason & VM_UFFD_MINOR)
+ msg.arg.pagefault.flags |= UFFD_PAGEFAULT_FLAG_MINOR;
if (features & UFFD_FEATURE_THREAD_ID)
msg.arg.pagefault.feat.ptid = task_pid_vnr(current);
return msg;
BUG_ON(ctx->mm != mm);
- VM_BUG_ON(reason & ~(VM_UFFD_MISSING|VM_UFFD_WP));
- VM_BUG_ON(!(reason & VM_UFFD_MISSING) ^ !!(reason & VM_UFFD_WP));
+ /* Any unrecognized flag is a bug. */
+ VM_BUG_ON(reason & ~__VM_UFFD_FLAGS);
+ /* 0 or > 1 flags set is a bug; we expect exactly 1. */
+ VM_BUG_ON(!reason || (reason & (reason - 1)));
if (ctx->features & UFFD_FEATURE_SIGBUS)
goto out;
for (vma = mm->mmap; vma; vma = vma->vm_next)
if (vma->vm_userfaultfd_ctx.ctx == release_new_ctx) {
vma->vm_userfaultfd_ctx = NULL_VM_UFFD_CTX;
- vma->vm_flags &= ~(VM_UFFD_WP | VM_UFFD_MISSING);
+ vma->vm_flags &= ~__VM_UFFD_FLAGS;
}
mmap_write_unlock(mm);
octx = vma->vm_userfaultfd_ctx.ctx;
if (!octx || !(octx->features & UFFD_FEATURE_EVENT_FORK)) {
vma->vm_userfaultfd_ctx = NULL_VM_UFFD_CTX;
- vma->vm_flags &= ~(VM_UFFD_WP | VM_UFFD_MISSING);
+ vma->vm_flags &= ~__VM_UFFD_FLAGS;
return 0;
}
} else {
/* Drop uffd context if remap feature not enabled */
vma->vm_userfaultfd_ctx = NULL_VM_UFFD_CTX;
- vma->vm_flags &= ~(VM_UFFD_WP | VM_UFFD_MISSING);
+ vma->vm_flags &= ~__VM_UFFD_FLAGS;
}
}
for (vma = mm->mmap; vma; vma = vma->vm_next) {
cond_resched();
BUG_ON(!!vma->vm_userfaultfd_ctx.ctx ^
- !!(vma->vm_flags & (VM_UFFD_MISSING | VM_UFFD_WP)));
+ !!(vma->vm_flags & __VM_UFFD_FLAGS));
if (vma->vm_userfaultfd_ctx.ctx != ctx) {
prev = vma;
continue;
}
- new_flags = vma->vm_flags & ~(VM_UFFD_MISSING | VM_UFFD_WP);
+ new_flags = vma->vm_flags & ~__VM_UFFD_FLAGS;
prev = vma_merge(mm, prev, vma->vm_start, vma->vm_end,
new_flags, vma->anon_vma,
vma->vm_file, vma->vm_pgoff,
unsigned long vm_flags)
{
/* FIXME: add WP support to hugetlbfs and shmem */
- return vma_is_anonymous(vma) ||
- ((is_vm_hugetlb_page(vma) || vma_is_shmem(vma)) &&
- !(vm_flags & VM_UFFD_WP));
+ if (vm_flags & VM_UFFD_WP) {
+ if (is_vm_hugetlb_page(vma) || vma_is_shmem(vma))
+ return false;
+ }
+
+ if (vm_flags & VM_UFFD_MINOR) {
+ /* FIXME: Add minor fault interception for shmem. */
+ if (!is_vm_hugetlb_page(vma))
+ return false;
+ }
+
+ return vma_is_anonymous(vma) || is_vm_hugetlb_page(vma) ||
+ vma_is_shmem(vma);
}
static int userfaultfd_register(struct userfaultfd_ctx *ctx,
ret = -EINVAL;
if (!uffdio_register.mode)
goto out;
- if (uffdio_register.mode & ~(UFFDIO_REGISTER_MODE_MISSING|
- UFFDIO_REGISTER_MODE_WP))
+ if (uffdio_register.mode & ~UFFD_API_REGISTER_MODES)
goto out;
vm_flags = 0;
if (uffdio_register.mode & UFFDIO_REGISTER_MODE_MISSING)
vm_flags |= VM_UFFD_MISSING;
if (uffdio_register.mode & UFFDIO_REGISTER_MODE_WP)
vm_flags |= VM_UFFD_WP;
+ if (uffdio_register.mode & UFFDIO_REGISTER_MODE_MINOR) {
+#ifndef CONFIG_HAVE_ARCH_USERFAULTFD_MINOR
+ goto out;
+#endif
+ vm_flags |= VM_UFFD_MINOR;
+ }
ret = validate_range(mm, &uffdio_register.range.start,
uffdio_register.range.len);
cond_resched();
BUG_ON(!!cur->vm_userfaultfd_ctx.ctx ^
- !!(cur->vm_flags & (VM_UFFD_MISSING | VM_UFFD_WP)));
+ !!(cur->vm_flags & __VM_UFFD_FLAGS));
/* check not compatible vmas */
ret = -EINVAL;
start = vma->vm_start;
vma_end = min(end, vma->vm_end);
- new_flags = (vma->vm_flags &
- ~(VM_UFFD_MISSING|VM_UFFD_WP)) | vm_flags;
+ new_flags = (vma->vm_flags & ~__VM_UFFD_FLAGS) | vm_flags;
prev = vma_merge(mm, prev, start, vma_end, new_flags,
vma->anon_vma, vma->vm_file, vma->vm_pgoff,
vma_policy(vma),
vma->vm_flags = new_flags;
vma->vm_userfaultfd_ctx.ctx = ctx;
+ if (is_vm_hugetlb_page(vma) && uffd_disable_huge_pmd_share(vma))
+ hugetlb_unshare_all_pmds(vma);
+
skip:
prev = vma;
start = vma->vm_end;
if (!(uffdio_register.mode & UFFDIO_REGISTER_MODE_WP))
ioctls_out &= ~((__u64)1 << _UFFDIO_WRITEPROTECT);
+ /* CONTINUE ioctl is only supported for MINOR ranges. */
+ if (!(uffdio_register.mode & UFFDIO_REGISTER_MODE_MINOR))
+ ioctls_out &= ~((__u64)1 << _UFFDIO_CONTINUE);
+
/*
* Now that we scanned all vmas we can already tell
* userland which ioctls methods are guaranteed to
cond_resched();
BUG_ON(!!cur->vm_userfaultfd_ctx.ctx ^
- !!(cur->vm_flags & (VM_UFFD_MISSING | VM_UFFD_WP)));
+ !!(cur->vm_flags & __VM_UFFD_FLAGS));
/*
* Check not compatible vmas, not strictly required
wake_userfault(vma->vm_userfaultfd_ctx.ctx, &range);
}
- new_flags = vma->vm_flags & ~(VM_UFFD_MISSING | VM_UFFD_WP);
+ new_flags = vma->vm_flags & ~__VM_UFFD_FLAGS;
prev = vma_merge(mm, prev, start, vma_end, new_flags,
vma->anon_vma, vma->vm_file, vma->vm_pgoff,
vma_policy(vma),
return ret;
}
+static int userfaultfd_continue(struct userfaultfd_ctx *ctx, unsigned long arg)
+{
+ __s64 ret;
+ struct uffdio_continue uffdio_continue;
+ struct uffdio_continue __user *user_uffdio_continue;
+ struct userfaultfd_wake_range range;
+
+ user_uffdio_continue = (struct uffdio_continue __user *)arg;
+
+ ret = -EAGAIN;
+ if (READ_ONCE(ctx->mmap_changing))
+ goto out;
+
+ ret = -EFAULT;
+ if (copy_from_user(&uffdio_continue, user_uffdio_continue,
+ /* don't copy the output fields */
+ sizeof(uffdio_continue) - (sizeof(__s64))))
+ goto out;
+
+ ret = validate_range(ctx->mm, &uffdio_continue.range.start,
+ uffdio_continue.range.len);
+ if (ret)
+ goto out;
+
+ ret = -EINVAL;
+ /* double check for wraparound just in case. */
+ if (uffdio_continue.range.start + uffdio_continue.range.len <=
+ uffdio_continue.range.start) {
+ goto out;
+ }
+ if (uffdio_continue.mode & ~UFFDIO_CONTINUE_MODE_DONTWAKE)
+ goto out;
+
+ if (mmget_not_zero(ctx->mm)) {
+ ret = mcopy_continue(ctx->mm, uffdio_continue.range.start,
+ uffdio_continue.range.len,
+ &ctx->mmap_changing);
+ mmput(ctx->mm);
+ } else {
+ return -ESRCH;
+ }
+
+ if (unlikely(put_user(ret, &user_uffdio_continue->mapped)))
+ return -EFAULT;
+ if (ret < 0)
+ goto out;
+
+ /* len == 0 would wake all */
+ BUG_ON(!ret);
+ range.len = ret;
+ if (!(uffdio_continue.mode & UFFDIO_CONTINUE_MODE_DONTWAKE)) {
+ range.start = uffdio_continue.range.start;
+ wake_userfault(ctx, &range);
+ }
+ ret = range.len == uffdio_continue.range.len ? 0 : -EAGAIN;
+
+out:
+ return ret;
+}
+
static inline unsigned int uffd_ctx_features(__u64 user_features)
{
/*
goto err_out;
/* report all available features and ioctls to userland */
uffdio_api.features = UFFD_API_FEATURES;
+#ifndef CONFIG_HAVE_ARCH_USERFAULTFD_MINOR
+ uffdio_api.features &= ~UFFD_FEATURE_MINOR_HUGETLBFS;
+#endif
uffdio_api.ioctls = UFFD_API_IOCTLS;
ret = -EFAULT;
if (copy_to_user(buf, &uffdio_api, sizeof(uffdio_api)))
case UFFDIO_WRITEPROTECT:
ret = userfaultfd_writeprotect(ctx, arg);
break;
+ case UFFDIO_CONTINUE:
+ ret = userfaultfd_continue(ctx, arg);
+ break;
}
return ret;
}
projects / linux-2.6-microblaze.git / blobdiff