Merge branch 'linux-linaro-lsk-v4.4' of git://git.linaro.org/kernel/linux-linaro-stable.git

* linux-linaro-lsk-v4.4: (519 commits)
  Linux 4.4.154
  cdrom: Fix info leak/OOB read in cdrom_ioctl_drive_status
  iscsi target: fix session creation failure handling
  scsi: core: Avoid that SCSI device removal through sysfs triggers a deadlock
  scsi: sysfs: Introduce sysfs_{un,}break_active_protection()
  MIPS: lib: Provide MIPS64r6 __multi3() for GCC < 7
  MIPS: Correct the 64-bit DSP accumulator register size
  kprobes: Make list and blacklist root user read only
  s390/pci: fix out of bounds access during irq setup
  s390/qdio: reset old sbal_state flags
  s390: fix br_r1_trampoline for machines without exrl
  x86/spectre: Add missing family 6 check to microcode check
  x86/irqflags: Mark native_restore_fl extern inline
  pinctrl: freescale: off by one in imx1_pinconf_group_dbg_show()
  ASoC: sirf: Fix potential NULL pointer dereference
  ASoC: dpcm: don't merge format from invalid codec dai
  udl-kms: fix crash due to uninitialized memory
  udl-kms: handle allocation failure
  udl-kms: change down_interruptible to down
  fuse: Add missed unlock_page() to fuse_readpages_fill()
  ...

Conflicts:
	Makefile
	arch/arm64/mm/init.c
	fs/squashfs/block.c
	include/uapi/linux/prctl.h
	kernel/sys.c

Change-Id: Ie03b5adfbbb4ab2bf16bc55d99f0d8a9c540a53b

1 files changed, 49 insertions, 0 deletions

diff --git a/mm/mprotect.c b/mm/mprotect.c
index b8849a3930a0..fcd678c3bd24 100644
--- a/mm/mprotect.c
+++ b/mm/mprotect.c
@@ -255,6 +255,42 @@ unsigned long change_protection(struct vm_area_struct *vma, unsigned long start,
 	return pages;
 }
 
+static int prot_none_pte_entry(pte_t *pte, unsigned long addr,
+			       unsigned long next, struct mm_walk *walk)
+{
+	return pfn_modify_allowed(pte_pfn(*pte), *(pgprot_t *)(walk->private)) ?
+		0 : -EACCES;
+}
+
+static int prot_none_hugetlb_entry(pte_t *pte, unsigned long hmask,
+				   unsigned long addr, unsigned long next,
+				   struct mm_walk *walk)
+{
+	return pfn_modify_allowed(pte_pfn(*pte), *(pgprot_t *)(walk->private)) ?
+		0 : -EACCES;
+}
+
+static int prot_none_test(unsigned long addr, unsigned long next,
+			  struct mm_walk *walk)
+{
+	return 0;
+}
+
+static int prot_none_walk(struct vm_area_struct *vma, unsigned long start,
+			   unsigned long end, unsigned long newflags)
+{
+	pgprot_t new_pgprot = vm_get_page_prot(newflags);
+	struct mm_walk prot_none_walk = {
+		.pte_entry = prot_none_pte_entry,
+		.hugetlb_entry = prot_none_hugetlb_entry,
+		.test_walk = prot_none_test,
+		.mm = current->mm,
+		.private = &new_pgprot,
+	};
+
+	return walk_page_range(start, end, &prot_none_walk);
+}
+
 int
 mprotect_fixup(struct vm_area_struct *vma, struct vm_area_struct **pprev,
 	unsigned long start, unsigned long end, unsigned long newflags)
@@ -273,6 +309,19 @@ mprotect_fixup(struct vm_area_struct *vma, struct vm_area_struct **pprev,
 	}
 
 	/*
+	 * Do PROT_NONE PFN permission checks here when we can still
+	 * bail out without undoing a lot of state. This is a rather
+	 * uncommon case, so doesn't need to be very optimized.
+	 */
+	if (arch_has_pfn_modify_check() &&
+	    (vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP)) &&
+	    (newflags & (VM_READ|VM_WRITE|VM_EXEC)) == 0) {
+		error = prot_none_walk(vma, start, end, newflags);
+		if (error)
+			return error;
+	}
+
+	/*
 	 * If we make a private mapping writable we increase our commit;
 	 * but (without finer accounting) cannot reduce our commit if we
 	 * make it unwritable again. hugetlb mapping were accounted for