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    Subject[PATCH v25 21/30] mm: Re-introduce vm_flags to do_mmap()
    Date
    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_SHADOW_STACK to
    do_mmap(). Thus, re-introduce vm_flags to do_mmap().

    Signed-off-by: Yu-cheng Yu <yu-cheng.yu@intel.com>
    Reviewed-by: Peter Collingbourne <pcc@google.com>
    Reviewed-by: Kees Cook <keescook@chromium.org>
    Cc: Andrew Morton <akpm@linux-foundation.org>
    Cc: Oleg Nesterov <oleg@redhat.com>
    Cc: linux-mm@kvack.org
    ---
    v24:
    - Change VM_SHSTK to VM_SHADOW_STACK.
    - Update commit log.

    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 3e9c84f21ef6..1ccec5cc399b 100644
    --- a/include/linux/mm.h
    +++ b/include/linux/mm.h
    @@ -2576,7 +2576,8 @@ 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 d77fb39b6ab5..7b2992ef8ee0 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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