--- /dev/null
+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
+@@ -16,4 +16,5 @@ 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
+@@ -10,10 +10,18 @@ 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
+@@ -23,4 +31,13 @@ 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 */
--- /dev/null
+From c9dccf1d074a67d36c510845f663980d69e3409b Mon Sep 17 00:00:00 2001
+From: Sam Bobroff <sam.bobroff@au1.ibm.com>
+Date: Mon, 12 Feb 2018 11:19:29 +1100
+Subject: powerpc/pseries: Enable RAS hotplug events later
+
+From: Sam Bobroff <sam.bobroff@au1.ibm.com>
+
+commit c9dccf1d074a67d36c510845f663980d69e3409b upstream.
+
+Currently if the kernel receives a memory hot-unplug event early
+enough, it may get stuck in an infinite loop in
+dissolve_free_huge_pages(). This appears as a stall just after:
+
+ pseries-hotplug-mem: Attempting to hot-remove XX LMB(s) at YYYYYYYY
+
+It appears to be caused by "minimum_order" being uninitialized, due to
+init_ras_IRQ() executing before hugetlb_init().
+
+To correct this, extract the part of init_ras_IRQ() that enables
+hotplug event processing and place it in the machine_late_initcall
+phase, which is guaranteed to be after hugetlb_init() is called.
+
+Signed-off-by: Sam Bobroff <sam.bobroff@au1.ibm.com>
+Acked-by: Balbir Singh <bsingharora@gmail.com>
+[mpe: Reorder the functions to make the diff readable]
+Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
+Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+
+---
+ arch/powerpc/platforms/pseries/ras.c | 31 ++++++++++++++++++++++---------
+ 1 file changed, 22 insertions(+), 9 deletions(-)
+
+--- a/arch/powerpc/platforms/pseries/ras.c
++++ b/arch/powerpc/platforms/pseries/ras.c
+@@ -49,6 +49,28 @@ static irqreturn_t ras_error_interrupt(i
+
+
+ /*
++ * Enable the hotplug interrupt late because processing them may touch other
++ * devices or systems (e.g. hugepages) that have not been initialized at the
++ * subsys stage.
++ */
++int __init init_ras_hotplug_IRQ(void)
++{
++ struct device_node *np;
++
++ /* Hotplug Events */
++ np = of_find_node_by_path("/event-sources/hot-plug-events");
++ if (np != NULL) {
++ if (dlpar_workqueue_init() == 0)
++ request_event_sources_irqs(np, ras_hotplug_interrupt,
++ "RAS_HOTPLUG");
++ of_node_put(np);
++ }
++
++ return 0;
++}
++machine_late_initcall(pseries, init_ras_hotplug_IRQ);
++
++/*
+ * Initialize handlers for the set of interrupts caused by hardware errors
+ * and power system events.
+ */
+@@ -66,15 +88,6 @@ static int __init init_ras_IRQ(void)
+ of_node_put(np);
+ }
+
+- /* Hotplug Events */
+- np = of_find_node_by_path("/event-sources/hot-plug-events");
+- if (np != NULL) {
+- if (dlpar_workqueue_init() == 0)
+- request_event_sources_irqs(np, ras_hotplug_interrupt,
+- "RAS_HOTPLUG");
+- of_node_put(np);
+- }
+-
+ /* EPOW Events */
+ np = of_find_node_by_path("/event-sources/epow-events");
+ if (np != NULL) {
projects / thirdparty / kernel / stable-queue.git / commitdiff
