Merge branch 'parisc-4.11-3' of git://git.kernel.org/pub/scm/linux/kernel/git/deller/parisc-linux

Pull parisc fixes from Helge Deller:
 "Al Viro reported that - in case of read faults - our copy_from_user()
  implementation may claim to have copied more bytes than it actually
  did. In order to fix this bug and because of the way how gcc optimizes
  register usage for inline assembly in C code, we had to replace our
  pa_memcpy() function with a pure assembler implementation.

  While fixing the memcpy bug we noticed some other issues with our
  get_user() and put_user() functions, e.g. nested faults may return
  wrong data. This is now fixed by a common fixup handler for
  get_user/put_user in the exception handler which additionally makes
  generated code smaller and faster.

  The third patch is a trivial one-line fix for a patch which went in
  during 4.11-rc and which avoids stalled CPU warnings after power
  shutdown (for parisc machines which can't plug power off themselves).

  Due to the rewrite of pa_memcpy() into assembly this patch got bigger
  than what I wanted to have sent at this stage.

  Those patches have been running in production during the last few days
  on our debian build servers without any further issues"

* 'parisc-4.11-3' of git://git.kernel.org/pub/scm/linux/kernel/git/deller/parisc-linux:
  parisc: Avoid stalled CPU warnings after system shutdown
  parisc: Clean up fixup routines for get_user()/put_user()
  parisc: Fix access fault handling in pa_memcpy()

1 files changed, 17 insertions, 0 deletions

diff --git a/arch/parisc/mm/fault.c b/arch/parisc/mm/fault.c
index deab89a8915a..32ec22146141 100644
--- a/arch/parisc/mm/fault.c
+++ b/arch/parisc/mm/fault.c
@@ -150,6 +150,23 @@ int fixup_exception(struct pt_regs *regs)
                 d->fault_space = regs->isr;
                 d->fault_addr = regs->ior;
 
+                /*
+                 * Fix up get_user() and put_user().
+                 * ASM_EXCEPTIONTABLE_ENTRY_EFAULT() sets the least-significant
+                 * bit in the relative address of the fixup routine to indicate
+                 * that %r8 should be loaded with -EFAULT to report a userspace
+                 * access error.
+                 */
+                if (fix->fixup & 1) {
+                        regs->gr[8] = -EFAULT;
+
+                        /* zero target register for get_user() */
+                        if (parisc_acctyp(0, regs->iir) == VM_READ) {
+                                int treg = regs->iir & 0x1f;
+                                regs->gr[treg] = 0;
+                        }
+                }
+
                 regs->iaoq[0] = (unsigned long)&fix->fixup + fix->fixup;
                 regs->iaoq[0] &= ~3;
                 /*