There was no more caller passing vm_flags to do_mmap(), and vm_flags was
removed from the function's input by:

    commit 45e55300f114 ("mm: remove unnecessary wrapper function 
do_mmap_pgoff()").

There is a new user now.  Shadow stack allocation passes VM_SHSTK to
do_mmap().  Re-introduce vm_flags to do_mmap(), but without the old wrapper
do_mmap_pgoff().  Instead, make all callers of the wrapper pass a zero
vm_flags to do_mmap().

Signed-off-by: Yu-cheng Yu <yu-cheng...@intel.com>
Reviewed-by: Peter Collingbourne <p...@google.com>
Reviewed-by: Kees Cook <keesc...@chromium.org>
Cc: Andrew Morton <a...@linux-foundation.org>
Cc: Oleg Nesterov <o...@redhat.com>
Cc: linux...@kvack.org
---
 fs/aio.c           |  2 +-
 include/linux/mm.h |  3 ++-
 ipc/shm.c          |  2 +-
 mm/mmap.c          | 10 +++++-----
 mm/nommu.c         |  4 ++--
 mm/util.c          |  2 +-
 6 files changed, 12 insertions(+), 11 deletions(-)

diff --git a/fs/aio.c b/fs/aio.c
index 1f32da13d39e..b5d0586209a7 100644
--- a/fs/aio.c
+++ b/fs/aio.c
@@ -529,7 +529,7 @@ static int aio_setup_ring(struct kioctx *ctx, unsigned int 
nr_events)
 
        ctx->mmap_base = do_mmap(ctx->aio_ring_file, 0, ctx->mmap_size,
                                 PROT_READ | PROT_WRITE,
-                                MAP_SHARED, 0, &unused, NULL);
+                                MAP_SHARED, 0, 0, &unused, NULL);
        mmap_write_unlock(mm);
        if (IS_ERR((void *)ctx->mmap_base)) {
                ctx->mmap_size = 0;
diff --git a/include/linux/mm.h b/include/linux/mm.h
index 9890e9f5a5e0..e178be052419 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -2564,7 +2564,8 @@ extern unsigned long mmap_region(struct file *file, 
unsigned long addr,
        struct list_head *uf);
 extern unsigned long do_mmap(struct file *file, unsigned long addr,
        unsigned long len, unsigned long prot, unsigned long flags,
-       unsigned long pgoff, unsigned long *populate, struct list_head *uf);
+       vm_flags_t vm_flags, unsigned long pgoff, unsigned long *populate,
+       struct list_head *uf);
 extern int __do_munmap(struct mm_struct *, unsigned long, size_t,
                       struct list_head *uf, bool downgrade);
 extern int do_munmap(struct mm_struct *, unsigned long, size_t,
diff --git a/ipc/shm.c b/ipc/shm.c
index febd88daba8c..b6370eb1eaab 100644
--- a/ipc/shm.c
+++ b/ipc/shm.c
@@ -1556,7 +1556,7 @@ long do_shmat(int shmid, char __user *shmaddr, int shmflg,
                        goto invalid;
        }
 
-       addr = do_mmap(file, addr, size, prot, flags, 0, &populate, NULL);
+       addr = do_mmap(file, addr, size, prot, flags, 0, 0, &populate, NULL);
        *raddr = addr;
        err = 0;
        if (IS_ERR_VALUE(addr))
diff --git a/mm/mmap.c b/mm/mmap.c
index 2ac67882ace2..99077171010b 100644
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -1401,11 +1401,11 @@ static inline bool file_mmap_ok(struct file *file, 
struct inode *inode,
  */
 unsigned long do_mmap(struct file *file, unsigned long addr,
                        unsigned long len, unsigned long prot,
-                       unsigned long flags, unsigned long pgoff,
-                       unsigned long *populate, struct list_head *uf)
+                       unsigned long flags, vm_flags_t vm_flags,
+                       unsigned long pgoff, unsigned long *populate,
+                       struct list_head *uf)
 {
        struct mm_struct *mm = current->mm;
-       vm_flags_t vm_flags;
        int pkey = 0;
 
        *populate = 0;
@@ -1467,7 +1467,7 @@ unsigned long do_mmap(struct file *file, unsigned long 
addr,
         * to. we assume access permissions have been handled by the open
         * of the memory object, so we don't do any here.
         */
-       vm_flags = calc_vm_prot_bits(prot, pkey) | calc_vm_flag_bits(flags) |
+       vm_flags |= calc_vm_prot_bits(prot, pkey) | calc_vm_flag_bits(flags) |
                        mm->def_flags | VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC;
 
        if (flags & MAP_LOCKED)
@@ -3047,7 +3047,7 @@ SYSCALL_DEFINE5(remap_file_pages, unsigned long, start, 
unsigned long, size,
 
        file = get_file(vma->vm_file);
        ret = do_mmap(vma->vm_file, start, size,
-                       prot, flags, pgoff, &populate, NULL);
+                       prot, flags, 0, pgoff, &populate, NULL);
        fput(file);
 out:
        mmap_write_unlock(mm);
diff --git a/mm/nommu.c b/mm/nommu.c
index 5c9ab799c0e6..9b6f7a1895c2 100644
--- a/mm/nommu.c
+++ b/mm/nommu.c
@@ -1071,6 +1071,7 @@ unsigned long do_mmap(struct file *file,
                        unsigned long len,
                        unsigned long prot,
                        unsigned long flags,
+                       vm_flags_t vm_flags,
                        unsigned long pgoff,
                        unsigned long *populate,
                        struct list_head *uf)
@@ -1078,7 +1079,6 @@ unsigned long do_mmap(struct file *file,
        struct vm_area_struct *vma;
        struct vm_region *region;
        struct rb_node *rb;
-       vm_flags_t vm_flags;
        unsigned long capabilities, result;
        int ret;
 
@@ -1097,7 +1097,7 @@ unsigned long do_mmap(struct file *file,
 
        /* 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);
diff --git a/mm/util.c b/mm/util.c
index 54870226cea6..49cbd4400d13 100644
--- a/mm/util.c
+++ b/mm/util.c
@@ -516,7 +516,7 @@ unsigned long vm_mmap_pgoff(struct file *file, unsigned 
long addr,
        if (!ret) {
                if (mmap_write_lock_killable(mm))
                        return -EINTR;
-               ret = do_mmap(file, addr, len, prot, flag, pgoff, &populate,
+               ret = do_mmap(file, addr, len, prot, flag, 0, pgoff, &populate,
                              &uf);
                mmap_write_unlock(mm);
                userfaultfd_unmap_complete(mm, &uf);
-- 
2.21.0

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