Update Linux to v5.4.148

Sourced from [1]

[1] https://cdn.kernel.org/pub/linux/kernel/v5.x/linux-5.4.148.tar.gz

Change-Id: Ib3d26c5ba9b022e2e03533005c4fed4d7c30b61b
Signed-off-by: Olivier Deprez <olivier.deprez@arm.com>
diff --git a/mm/mmap.c b/mm/mmap.c
index a7d8c84..ba78f1f 100644
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -90,12 +90,6 @@
  * MAP_PRIVATE	r: (no) no	r: (yes) yes	r: (no) yes	r: (no) yes
  *		w: (no) no	w: (no) no	w: (copy) copy	w: (no) no
  *		x: (no) no	x: (no) yes	x: (no) yes	x: (yes) yes
- *
- * On arm64, PROT_EXEC has the following behaviour for both MAP_SHARED and
- * MAP_PRIVATE:
- *								r: (no) no
- *								w: (no) no
- *								x: (yes) yes
  */
 pgprot_t protection_map[16] __ro_after_init = {
 	__P000, __P001, __P010, __P011, __P100, __P101, __P110, __P111,
@@ -201,8 +195,6 @@
 	bool downgraded = false;
 	LIST_HEAD(uf);
 
-	brk = untagged_addr(brk);
-
 	if (down_write_killable(&mm->mmap_sem))
 		return -EINTR;
 
@@ -1589,8 +1581,6 @@
 	struct file *file = NULL;
 	unsigned long retval;
 
-	addr = untagged_addr(addr);
-
 	if (!(flags & MAP_ANONYMOUS)) {
 		audit_mmap_fd(fd, flags);
 		file = fget(fd);
@@ -2136,6 +2126,7 @@
 	info.low_limit = mm->mmap_base;
 	info.high_limit = mmap_end;
 	info.align_mask = 0;
+	info.align_offset = 0;
 	return vm_unmapped_area(&info);
 }
 #endif
@@ -2177,6 +2168,7 @@
 	info.low_limit = max(PAGE_SIZE, mmap_min_addr);
 	info.high_limit = arch_get_mmap_base(addr, mm->mmap_base);
 	info.align_mask = 0;
+	info.align_offset = 0;
 	addr = vm_unmapped_area(&info);
 
 	/*
@@ -2632,7 +2624,7 @@
  * Create a list of vma's touched by the unmap, removing them from the mm's
  * vma list as we go..
  */
-static void
+static bool
 detach_vmas_to_be_unmapped(struct mm_struct *mm, struct vm_area_struct *vma,
 	struct vm_area_struct *prev, unsigned long end)
 {
@@ -2657,6 +2649,17 @@
 
 	/* Kill the cache */
 	vmacache_invalidate(mm);
+
+	/*
+	 * Do not downgrade mmap_lock if we are next to VM_GROWSDOWN or
+	 * VM_GROWSUP VMA. Such VMAs can change their size under
+	 * down_read(mmap_lock) and collide with the VMA we are about to unmap.
+	 */
+	if (vma && (vma->vm_flags & VM_GROWSDOWN))
+		return false;
+	if (prev && (prev->vm_flags & VM_GROWSUP))
+		return false;
+	return true;
 }
 
 /*
@@ -2837,7 +2840,8 @@
 	}
 
 	/* Detach vmas from rbtree */
-	detach_vmas_to_be_unmapped(mm, vma, prev, end);
+	if (!detach_vmas_to_be_unmapped(mm, vma, prev, end))
+		downgrade = false;
 
 	if (downgrade)
 		downgrade_write(&mm->mmap_sem);
@@ -3170,6 +3174,7 @@
 		if (vma->vm_flags & VM_ACCOUNT)
 			nr_accounted += vma_pages(vma);
 		vma = remove_vma(vma);
+		cond_resched();
 	}
 	vm_unacct_memory(nr_accounted);
 }