4.4-stable patches

added patches:
	mips-implement-__multi3-for-gcc7-mips64r6-builds.patch

diff --git a/queue-4.4/mips-implement-__multi3-for-gcc7-mips64r6-builds.patch b/queue-4.4/mips-implement-__multi3-for-gcc7-mips64r6-builds.patch
new file mode 100644 (file)
index 0000000..b398563
--- /dev/null
+++ b/queue-4.4/mips-implement-__multi3-for-gcc7-mips64r6-builds.patch
@@ -0,0 +1,145 @@
+From ebabcf17bcd7ce968b1631ebe08236275698f39b Mon Sep 17 00:00:00 2001
+From: James Hogan <jhogan@kernel.org>
+Date: Thu, 7 Dec 2017 07:20:46 +0000
+Subject: MIPS: Implement __multi3 for GCC7 MIPS64r6 builds
+
+From: James Hogan <jhogan@kernel.org>
+
+commit ebabcf17bcd7ce968b1631ebe08236275698f39b upstream.
+
+GCC7 is a bit too eager to generate suboptimal __multi3 calls (128bit
+multiply with 128bit result) for MIPS64r6 builds, even in code which
+doesn't explicitly use 128bit types, such as the following:
+
+unsigned long func(unsigned long a, unsigned long b)
+{
+       return a > (~0UL) / b;
+}
+
+Which GCC rearanges to:
+
+return (unsigned __int128)a * (unsigned __int128)b > 0xffffffffffffffff;
+
+Therefore implement __multi3, but only for MIPS64r6 with GCC7 as under
+normal circumstances we wouldn't expect any calls to __multi3 to be
+generated from kernel code.
+
+Reported-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
+Signed-off-by: James Hogan <jhogan@kernel.org>
+Tested-by: Waldemar Brodkorb <wbx@openadk.org>
+Cc: Ralf Baechle <ralf@linux-mips.org>
+Cc: Maciej W. Rozycki <macro@mips.com>
+Cc: Matthew Fortune <matthew.fortune@mips.com>
+Cc: Florian Fainelli <florian@openwrt.org>
+Cc: linux-mips@linux-mips.org
+Patchwork: https://patchwork.linux-mips.org/patch/17890/
+Cc: Guenter Roeck <linux@roeck-us.net>
+Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+
+---
+ arch/mips/lib/Makefile |    3 +-
+ arch/mips/lib/libgcc.h |   17 +++++++++++++++
+ arch/mips/lib/multi3.c |   54 +++++++++++++++++++++++++++++++++++++++++++++++++
+ 3 files changed, 73 insertions(+), 1 deletion(-)
+
+--- a/arch/mips/lib/Makefile
++++ b/arch/mips/lib/Makefile
+@@ -15,4 +15,5 @@ obj-$(CONFIG_CPU_R3000)              += r3k_dump_tlb
+ obj-$(CONFIG_CPU_TX39XX)      += r3k_dump_tlb.o
+ 
+ # libgcc-style stuff needed in the kernel
+-obj-y += ashldi3.o ashrdi3.o bswapsi.o bswapdi.o cmpdi2.o lshrdi3.o ucmpdi2.o
++obj-y += ashldi3.o ashrdi3.o bswapsi.o bswapdi.o cmpdi2.o lshrdi3.o multi3.o \
++       ucmpdi2.o
+--- a/arch/mips/lib/libgcc.h
++++ b/arch/mips/lib/libgcc.h
+@@ -9,10 +9,18 @@ typedef int word_type __attribute__ ((mo
+ struct DWstruct {
+       int high, low;
+ };
++
++struct TWstruct {
++      long long high, low;
++};
+ #elif defined(__LITTLE_ENDIAN)
+ struct DWstruct {
+       int low, high;
+ };
++
++struct TWstruct {
++      long long low, high;
++};
+ #else
+ #error I feel sick.
+ #endif
+@@ -22,4 +30,13 @@ typedef union {
+       long long ll;
+ } DWunion;
+ 
++#if defined(CONFIG_64BIT) && defined(CONFIG_CPU_MIPSR6)
++typedef int ti_type __attribute__((mode(TI)));
++
++typedef union {
++      struct TWstruct s;
++      ti_type ti;
++} TWunion;
++#endif
++
+ #endif /* __ASM_LIBGCC_H */
+--- /dev/null
++++ b/arch/mips/lib/multi3.c
+@@ -0,0 +1,54 @@
++// SPDX-License-Identifier: GPL-2.0
++#include <linux/export.h>
++
++#include "libgcc.h"
++
++/*
++ * GCC 7 suboptimally generates __multi3 calls for mips64r6, so for that
++ * specific case only we'll implement it here.
++ *
++ * See https://gcc.gnu.org/bugzilla/show_bug.cgi?id=82981
++ */
++#if defined(CONFIG_64BIT) && defined(CONFIG_CPU_MIPSR6) && (__GNUC__ == 7)
++
++/* multiply 64-bit values, low 64-bits returned */
++static inline long long notrace dmulu(long long a, long long b)
++{
++      long long res;
++
++      asm ("dmulu %0,%1,%2" : "=r" (res) : "r" (a), "r" (b));
++      return res;
++}
++
++/* multiply 64-bit unsigned values, high 64-bits of 128-bit result returned */
++static inline long long notrace dmuhu(long long a, long long b)
++{
++      long long res;
++
++      asm ("dmuhu %0,%1,%2" : "=r" (res) : "r" (a), "r" (b));
++      return res;
++}
++
++/* multiply 128-bit values, low 128-bits returned */
++ti_type notrace __multi3(ti_type a, ti_type b)
++{
++      TWunion res, aa, bb;
++
++      aa.ti = a;
++      bb.ti = b;
++
++      /*
++       * a * b =           (a.lo * b.lo)
++       *         + 2^64  * (a.hi * b.lo + a.lo * b.hi)
++       *        [+ 2^128 * (a.hi * b.hi)]
++       */
++      res.s.low = dmulu(aa.s.low, bb.s.low);
++      res.s.high = dmuhu(aa.s.low, bb.s.low);
++      res.s.high += dmulu(aa.s.high, bb.s.low);
++      res.s.high += dmulu(aa.s.low, bb.s.high);
++
++      return res.ti;
++}
++EXPORT_SYMBOL(__multi3);
++
++#endif /* 64BIT && CPU_MIPSR6 && GCC7 */

diff --git a/queue-4.4/series b/queue-4.4/series
index 7c55cc574aaff66362ddad950539f289cdc2f17b..f84e769212fad03411c3d4cdb5f6dcac10846fbc 100644 (file)
--- a/queue-4.4/series
+++ b/queue-4.4/series
@@ -31,3 +31,4 @@ xen-gntdev-fix-off-by-one-error-when-unmapping-with-holes.patch
 xen-gntdev-fix-partial-gntdev_mmap-cleanup.patch
 sctp-make-use-of-pre-calculated-len.patch
 net-gianfar_ptp-move-set_fipers-to-spinlock-protecting-area.patch
+mips-implement-__multi3-for-gcc7-mips64r6-builds.patch