[PATCH v8 1/5] mm: untag user pointers in mmap/munmap/mremap/brk

[Catalin Marinas]

There isn't a good reason to differentiate between the user address
space layout modification syscalls and the other memory
permission/attributes ones (e.g. mprotect, madvise) w.r.t. the tagged
address ABI. Untag the user addresses on entry to these functions.

Signed-off-by: Catalin Marinas <catalin.mari...@arm.com>
---
 mm/mmap.c   | 5 +++++
 mm/mremap.c | 6 +-----
 2 files changed, 6 insertions(+), 5 deletions(-)

diff --git a/mm/mmap.c b/mm/mmap.c
index 7e8c3e8ae75f..b766b633b7ae 100644
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -201,6 +201,8 @@ SYSCALL_DEFINE1(brk, unsigned long, brk)
        bool downgraded = false;
        LIST_HEAD(uf);
 
+       brk = untagged_addr(brk);
+
        if (down_write_killable(&mm->mmap_sem))
                return -EINTR;
 
@@ -1573,6 +1575,8 @@ unsigned long ksys_mmap_pgoff(unsigned long addr, 
unsigned long len,
        struct file *file = NULL;
        unsigned long retval;
 
+       addr = untagged_addr(addr);
+
        if (!(flags & MAP_ANONYMOUS)) {
                audit_mmap_fd(fd, flags);
                file = fget(fd);
@@ -2874,6 +2878,7 @@ EXPORT_SYMBOL(vm_munmap);
 
 SYSCALL_DEFINE2(munmap, unsigned long, addr, size_t, len)
 {
+       addr = untagged_addr(addr);
        profile_munmap(addr);
        return __vm_munmap(addr, len, true);
 }
diff --git a/mm/mremap.c b/mm/mremap.c
index 64c9a3b8be0a..1fc8a29fbe3f 100644
--- a/mm/mremap.c
+++ b/mm/mremap.c
@@ -606,12 +606,8 @@ SYSCALL_DEFINE5(mremap, unsigned long, addr, unsigned 
long, old_len,
        LIST_HEAD(uf_unmap_early);
        LIST_HEAD(uf_unmap);
 
-       /*
-        * Architectures may interpret the tag passed to mmap as a background
-        * colour for the corresponding vma. For mremap we don't allow tagged
-        * new_addr to preserve similar behaviour to mmap.
-        */
        addr = untagged_addr(addr);
+       new_addr = untagged_addr(new_addr);
 
        if (flags & ~(MREMAP_FIXED | MREMAP_MAYMOVE))
                return ret;