releases/4.16.4/mips-uaccess-add-micromips-clobbers-to-bzero-invocation.patch

   1 From b3d7e55c3f886493235bfee08e1e5a4a27cbcce8 Mon Sep 17 00:00:00 2001
   2 From: Matt Redfearn <matt.redfearn@mips.com>
   3 Date: Tue, 17 Apr 2018 16:40:01 +0100
   4 Subject: MIPS: uaccess: Add micromips clobbers to bzero invocation
   5
   6 From: Matt Redfearn <matt.redfearn@mips.com>
   7
   8 commit b3d7e55c3f886493235bfee08e1e5a4a27cbcce8 upstream.
   9
  10 The micromips implementation of bzero additionally clobbers registers t7
  11 & t8. Specify this in the clobbers list when invoking bzero.
  12
  13 Fixes: 26c5e07d1478 ("MIPS: microMIPS: Optimise 'memset' core library function.")
  14 Reported-by: James Hogan <jhogan@kernel.org>
  15 Signed-off-by: Matt Redfearn <matt.redfearn@mips.com>
  16 Cc: Ralf Baechle <ralf@linux-mips.org>
  17 Cc: linux-mips@linux-mips.org
  18 Cc: <stable@vger.kernel.org> # 3.10+
  19 Patchwork: https://patchwork.linux-mips.org/patch/19110/
  20 Signed-off-by: James Hogan <jhogan@kernel.org>
  21 Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
  22
  23 ---
  24  arch/mips/include/asm/uaccess.h |   11 +++++++++--
  25  1 file changed, 9 insertions(+), 2 deletions(-)
  26
  27 --- a/arch/mips/include/asm/uaccess.h
  28 +++ b/arch/mips/include/asm/uaccess.h
  29 @@ -654,6 +654,13 @@ __clear_user(void __user *addr, __kernel
  30  {
  31         __kernel_size_t res;
  32
  33 +#ifdef CONFIG_CPU_MICROMIPS
  34 +/* micromips memset / bzero also clobbers t7 & t8 */
  35 +#define bzero_clobbers "$4", "$5", "$6", __UA_t0, __UA_t1, "$15", "$24", "$31"
  36 +#else
  37 +#define bzero_clobbers "$4", "$5", "$6", __UA_t0, __UA_t1, "$31"
  38 +#endif /* CONFIG_CPU_MICROMIPS */
  39 +
  40         if (eva_kernel_access()) {
  41                 __asm__ __volatile__(
  42                         "move\t$4, %1\n\t"
  43 @@ -663,7 +670,7 @@ __clear_user(void __user *addr, __kernel
  44                         "move\t%0, $6"
  45                         : "=r" (res)
  46                         : "r" (addr), "r" (size)
  47 -                       : "$4", "$5", "$6", __UA_t0, __UA_t1, "$31");
  48 +                       : bzero_clobbers);
  49         } else {
  50                 might_fault();
  51                 __asm__ __volatile__(
  52 @@ -674,7 +681,7 @@ __clear_user(void __user *addr, __kernel
  53                         "move\t%0, $6"
  54                         : "=r" (res)
  55                         : "r" (addr), "r" (size)
  56 -                       : "$4", "$5", "$6", __UA_t0, __UA_t1, "$31");
  57 +                       : bzero_clobbers);
  58         }
  59
  60         return res;