[PATCH AUTOSEL 4.14 006/150] powerpc: Fix signedness bug in update_flash_db()

[PATCH AUTOSEL 4.14 006/150] powerpc: Fix signedness bug in update_flash_db()

[Sasha Levin]

From: Dan Carpenter <dan.carpenter@oracle.com>

[ Upstream commit 014704e6f54189a203cc14c7c0bb411b940241bc ]

The "count < sizeof(struct os_area_db)" comparison is type promoted to
size_t so negative values of "count" are treated as very high values
and we accidentally return success instead of a negative error code.

This doesn't really change runtime much but it fixes a static checker
warning.

Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Acked-by: Geoff Levand <geoff@infradead.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 arch/powerpc/platforms/ps3/os-area.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/powerpc/platforms/ps3/os-area.c b/arch/powerpc/platforms/ps3/os-area.c
index 3db53e8aff927..9b2ef76578f06 100644
--- a/arch/powerpc/platforms/ps3/os-area.c
+++ b/arch/powerpc/platforms/ps3/os-area.c
@@ -664,7 +664,7 @@ static int update_flash_db(void)
 	db_set_64(db, &os_area_db_id_rtc_diff, saved_params.rtc_diff);
 
 	count = os_area_flash_write(db, sizeof(struct os_area_db), pos);
-	if (count < sizeof(struct os_area_db)) {
+	if (count < 0 || count < sizeof(struct os_area_db)) {
 		pr_debug("%s: os_area_flash_write failed %zd\n", __func__,
 			 count);
 		error = count < 0 ? count : -EIO;
-- 
2.20.1

[PATCH AUTOSEL 4.14 007/150] powerpc/boot: Disable vector instructions

[Sasha Levin]

From: Joel Stanley <joel@jms.id.au>

[ Upstream commit e8e132e6885962582784b6fa16a80d07ea739c0f ]

This will avoid auto-vectorisation when building with higher
optimisation levels.

We don't know if the machine can support VSX and even if it's present
it's probably not going to be enabled at this point in boot.

These flag were both added prior to GCC 4.6 which is the minimum
compiler version supported by upstream, thanks to Segher for the
details.

Signed-off-by: Joel Stanley <joel@jms.id.au>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 arch/powerpc/boot/Makefile | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/arch/powerpc/boot/Makefile b/arch/powerpc/boot/Makefile
index e2a5a932c24a8..5807c9d8e56d5 100644
--- a/arch/powerpc/boot/Makefile
+++ b/arch/powerpc/boot/Makefile
@@ -24,8 +24,8 @@ compress-$(CONFIG_KERNEL_GZIP) := CONFIG_KERNEL_GZIP
 compress-$(CONFIG_KERNEL_XZ)   := CONFIG_KERNEL_XZ
 
 BOOTCFLAGS    := -Wall -Wundef -Wstrict-prototypes -Wno-trigraphs \
-		 -fno-strict-aliasing -Os -msoft-float -pipe \
-		 -fomit-frame-pointer -fno-builtin -fPIC -nostdinc \
+		 -fno-strict-aliasing -Os -msoft-float -mno-altivec -mno-vsx \
+		 -pipe -fomit-frame-pointer -fno-builtin -fPIC -nostdinc \
 		 -D$(compress-y)
 
 BOOTCC := $(CC)
-- 
2.20.1

[PATCH AUTOSEL 4.14 008/150] powerpc/eeh: Fix use of EEH_PE_KEEP on wrong field

[Sasha Levin]

From: Sam Bobroff <sbobroff@linux.ibm.com>

[ Upstream commit 473af09b56dc4be68e4af33220ceca6be67aa60d ]

eeh_add_to_parent_pe() sometimes removes the EEH_PE_KEEP flag, but it
incorrectly removes it from pe->type, instead of pe->state.

However, rather than clearing it from the correct field, remove it.
Inspection of the code shows that it can't ever have had any effect
(even if it had been cleared from the correct field), because the
field is never tested after it is cleared by the statement in
question.

The clear statement was added by commit 807a827d4e74 ("powerpc/eeh:
Keep PE during hotplug"), but it didn't explain why it was necessary.

Signed-off-by: Sam Bobroff <sbobroff@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 arch/powerpc/kernel/eeh_pe.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/powerpc/kernel/eeh_pe.c b/arch/powerpc/kernel/eeh_pe.c
index 8545a9523b9bc..7339ca4fdc19e 100644
--- a/arch/powerpc/kernel/eeh_pe.c
+++ b/arch/powerpc/kernel/eeh_pe.c
@@ -381,7 +381,7 @@ int eeh_add_to_parent_pe(struct eeh_dev *edev)
 		while (parent) {
 			if (!(parent->type & EEH_PE_INVALID))
 				break;
-			parent->type &= ~(EEH_PE_INVALID | EEH_PE_KEEP);
+			parent->type &= ~EEH_PE_INVALID;
 			parent = parent->parent;
 		}
 
-- 
2.20.1

[PATCH AUTOSEL 4.14 048/150] macintosh/windfarm_smu_sat: Fix debug output

[Sasha Levin]

From: Benjamin Herrenschmidt <benh@kernel.crashing.org>

[ Upstream commit fc0c8b36d379a046525eacb9c3323ca635283757 ]

There's some antiquated debug output that's trying
to do a hand-made hexdump and turning into horrible
1-byte-per-line output these days.

Use print_hex_dump() instead

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/macintosh/windfarm_smu_sat.c | 25 +++++++------------------
 1 file changed, 7 insertions(+), 18 deletions(-)

diff --git a/drivers/macintosh/windfarm_smu_sat.c b/drivers/macintosh/windfarm_smu_sat.c
index da7f4fc1a51d1..a0f61eb853c55 100644
--- a/drivers/macintosh/windfarm_smu_sat.c
+++ b/drivers/macintosh/windfarm_smu_sat.c
@@ -22,14 +22,6 @@
 
 #define VERSION "1.0"
 
-#define DEBUG
-
-#ifdef DEBUG
-#define DBG(args...)	printk(args)
-#else
-#define DBG(args...)	do { } while(0)
-#endif
-
 /* If the cache is older than 800ms we'll refetch it */
 #define MAX_AGE		msecs_to_jiffies(800)
 
@@ -106,13 +98,10 @@ struct smu_sdbp_header *smu_sat_get_sdb_partition(unsigned int sat_id, int id,
 		buf[i+2] = data[3];
 		buf[i+3] = data[2];
 	}
-#ifdef DEBUG
-	DBG(KERN_DEBUG "sat %d partition %x:", sat_id, id);
-	for (i = 0; i < len; ++i)
-		DBG(" %x", buf[i]);
-	DBG("\n");
-#endif
 
+	printk(KERN_DEBUG "sat %d partition %x:", sat_id, id);
+	print_hex_dump(KERN_DEBUG, "  ", DUMP_PREFIX_OFFSET,
+		       16, 1, buf, len, false);
 	if (size)
 		*size = len;
 	return (struct smu_sdbp_header *) buf;
@@ -132,13 +121,13 @@ static int wf_sat_read_cache(struct wf_sat *sat)
 	if (err < 0)
 		return err;
 	sat->last_read = jiffies;
+
 #ifdef LOTSA_DEBUG
 	{
 		int i;
-		DBG(KERN_DEBUG "wf_sat_get: data is");
-		for (i = 0; i < 16; ++i)
-			DBG(" %.2x", sat->cache[i]);
-		DBG("\n");
+		printk(KERN_DEBUG "wf_sat_get: data is");
+		print_hex_dump(KERN_DEBUG, "  ", DUMP_PREFIX_OFFSET,
+			       16, 1, sat->cache, 16, false);
 	}
 #endif
 	return 0;
-- 
2.20.1

[PATCH AUTOSEL 4.14 059/150] powerpc/pseries: Export raw per-CPU VPA data via debugfs

[Sasha Levin]

From: Aravinda Prasad <aravinda@linux.vnet.ibm.com>

[ Upstream commit c6c26fb55e8e4b3fc376be5611685990a17de27a ]

This patch exports the raw per-CPU VPA data via debugfs.
A per-CPU file is created which exports the VPA data of
that CPU to help debug some of the VPA related issues or
to analyze the per-CPU VPA related statistics.

v3: Removed offline CPU check.

v2: Included offline CPU check and other review comments.

Signed-off-by: Aravinda Prasad <aravinda@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 arch/powerpc/platforms/pseries/lpar.c | 54 +++++++++++++++++++++++++++
 1 file changed, 54 insertions(+)

diff --git a/arch/powerpc/platforms/pseries/lpar.c b/arch/powerpc/platforms/pseries/lpar.c
index eb738ef577926..c0ae3847b8db5 100644
--- a/arch/powerpc/platforms/pseries/lpar.c
+++ b/arch/powerpc/platforms/pseries/lpar.c
@@ -48,6 +48,7 @@
 #include <asm/kexec.h>
 #include <asm/fadump.h>
 #include <asm/asm-prototypes.h>
+#include <asm/debugfs.h>
 
 #include "pseries.h"
 
@@ -1036,3 +1037,56 @@ static int __init reserve_vrma_context_id(void)
 	return 0;
 }
 machine_device_initcall(pseries, reserve_vrma_context_id);
+
+#ifdef CONFIG_DEBUG_FS
+/* debugfs file interface for vpa data */
+static ssize_t vpa_file_read(struct file *filp, char __user *buf, size_t len,
+			      loff_t *pos)
+{
+	int cpu = (long)filp->private_data;
+	struct lppaca *lppaca = &lppaca_of(cpu);
+
+	return simple_read_from_buffer(buf, len, pos, lppaca,
+				sizeof(struct lppaca));
+}
+
+static const struct file_operations vpa_fops = {
+	.open		= simple_open,
+	.read		= vpa_file_read,
+	.llseek		= default_llseek,
+};
+
+static int __init vpa_debugfs_init(void)
+{
+	char name[16];
+	long i;
+	static struct dentry *vpa_dir;
+
+	if (!firmware_has_feature(FW_FEATURE_SPLPAR))
+		return 0;
+
+	vpa_dir = debugfs_create_dir("vpa", powerpc_debugfs_root);
+	if (!vpa_dir) {
+		pr_warn("%s: can't create vpa root dir\n", __func__);
+		return -ENOMEM;
+	}
+
+	/* set up the per-cpu vpa file*/
+	for_each_possible_cpu(i) {
+		struct dentry *d;
+
+		sprintf(name, "cpu-%ld", i);
+
+		d = debugfs_create_file(name, 0400, vpa_dir, (void *)i,
+					&vpa_fops);
+		if (!d) {
+			pr_warn("%s: can't create per-cpu vpa file\n",
+					__func__);
+			return -ENOMEM;
+		}
+	}
+
+	return 0;
+}
+machine_arch_initcall(pseries, vpa_debugfs_init);
+#endif /* CONFIG_DEBUG_FS */
-- 
2.20.1

[PATCH AUTOSEL 4.14 076/150] powerpc/process: Fix flush_all_to_thread for SPE

[Sasha Levin]

From: Felipe Rechia <felipe.rechia@datacom.com.br>

[ Upstream commit e901378578c62202594cba0f6c076f3df365ec91 ]

Fix a bug introduced by the creation of flush_all_to_thread() for
processors that have SPE (Signal Processing Engine) and use it to
compute floating-point operations.

>From userspace perspective, the problem was seen in attempts of
computing floating-point operations which should generate exceptions.
For example:

  fork();
  float x = 0.0 / 0.0;
  isnan(x);           // forked process returns False (should be True)

The operation above also should always cause the SPEFSCR FINV bit to
be set. However, the SPE floating-point exceptions were turned off
after a fork().

Kernel versions prior to the bug used flush_spe_to_thread(), which
first saves SPEFSCR register values in tsk->thread and then calls
giveup_spe(tsk).

After commit 579e633e764e, the save_all() function was called first
to giveup_spe(), and then the SPEFSCR register values were saved in
tsk->thread. This would save the SPEFSCR register values after
disabling SPE for that thread, causing the bug described above.

Fixes 579e633e764e ("powerpc: create flush_all_to_thread()")
Signed-off-by: Felipe Rechia <felipe.rechia@datacom.com.br>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 arch/powerpc/kernel/process.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/arch/powerpc/kernel/process.c b/arch/powerpc/kernel/process.c
index 5e5da2073fdff..ba0d4f9a99bac 100644
--- a/arch/powerpc/kernel/process.c
+++ b/arch/powerpc/kernel/process.c
@@ -567,12 +567,11 @@ void flush_all_to_thread(struct task_struct *tsk)
 	if (tsk->thread.regs) {
 		preempt_disable();
 		BUG_ON(tsk != current);
-		save_all(tsk);
-
 #ifdef CONFIG_SPE
 		if (tsk->thread.regs->msr & MSR_SPE)
 			tsk->thread.spefscr = mfspr(SPRN_SPEFSCR);
 #endif
+		save_all(tsk);
 
 		preempt_enable();
 	}
-- 
2.20.1

[PATCH AUTOSEL 4.14 089/150] powerpc/xmon: Relax frame size for clang

[Sasha Levin]

From: Joel Stanley <joel@jms.id.au>

[ Upstream commit 9c87156cce5a63735d1218f0096a65c50a7a32aa ]

When building with clang (8 trunk, 7.0 release) the frame size limit is
hit:

 arch/powerpc/xmon/xmon.c:452:12: warning: stack frame size of 2576
 bytes in function 'xmon_core' [-Wframe-larger-than=]

Some investigation by Naveen indicates this is due to clang saving the
addresses to printf format strings on the stack.

While this issue is investigated, bump up the frame size limit for xmon
when building with clang.

Link: https://github.com/ClangBuiltLinux/linux/issues/252
Signed-off-by: Joel Stanley <joel@jms.id.au>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 arch/powerpc/xmon/Makefile | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/arch/powerpc/xmon/Makefile b/arch/powerpc/xmon/Makefile
index 549e99e71112b..ac5ee067aa512 100644
--- a/arch/powerpc/xmon/Makefile
+++ b/arch/powerpc/xmon/Makefile
@@ -13,6 +13,12 @@ UBSAN_SANITIZE := n
 ORIG_CFLAGS := $(KBUILD_CFLAGS)
 KBUILD_CFLAGS = $(subst -mno-sched-epilog,,$(subst $(CC_FLAGS_FTRACE),,$(ORIG_CFLAGS)))
 
+ifdef CONFIG_CC_IS_CLANG
+# clang stores addresses on the stack causing the frame size to blow
+# out. See https://github.com/ClangBuiltLinux/linux/issues/252
+KBUILD_CFLAGS += -Wframe-larger-than=4096
+endif
+
 ccflags-$(CONFIG_PPC64) := $(NO_MINIMAL_TOC)
 
 obj-y			+= xmon.o nonstdio.o spr_access.o
-- 
2.20.1

[PATCH AUTOSEL 4.14 090/150] selftests/powerpc/signal: Fix out-of-tree build

[Sasha Levin]

From: Joel Stanley <joel@jms.id.au>

[ Upstream commit 27825349d7b238533a47e3d98b8bb0efd886b752 ]

We should use TEST_GEN_PROGS, not TEST_PROGS. That tells the selftests
makefile (lib.mk) that those tests are generated (built), and so it
adds the $(OUTPUT) prefix for us, making the out-of-tree build work
correctly.

It also means we don't need our own clean rule, lib.mk does it.

We also have to update the signal_tm rule to use $(OUTPUT).

Signed-off-by: Joel Stanley <joel@jms.id.au>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 tools/testing/selftests/powerpc/signal/Makefile | 11 +++--------
 1 file changed, 3 insertions(+), 8 deletions(-)

diff --git a/tools/testing/selftests/powerpc/signal/Makefile b/tools/testing/selftests/powerpc/signal/Makefile
index a7cbd5082e271..4213978f3ee2c 100644
--- a/tools/testing/selftests/powerpc/signal/Makefile
+++ b/tools/testing/selftests/powerpc/signal/Makefile
@@ -1,14 +1,9 @@
 # SPDX-License-Identifier: GPL-2.0
-TEST_PROGS := signal signal_tm
-
-all: $(TEST_PROGS)
-
-$(TEST_PROGS): ../harness.c ../utils.c signal.S
+TEST_GEN_PROGS := signal signal_tm
 
 CFLAGS += -maltivec
-signal_tm: CFLAGS += -mhtm
+$(OUTPUT)/signal_tm: CFLAGS += -mhtm
 
 include ../../lib.mk
 
-clean:
-	rm -f $(TEST_PROGS) *.o
+$(TEST_GEN_PROGS): ../harness.c ../utils.c signal.S
-- 
2.20.1

[PATCH AUTOSEL 4.14 091/150] selftests/powerpc/switch_endian: Fix out-of-tree build

[Sasha Levin]

From: Michael Ellerman <mpe@ellerman.id.au>

[ Upstream commit 266bac361d5677e61a6815bd29abeb3bdced2b07 ]

For the out-of-tree build to work we need to tell switch_endian_test
to look for check-reversed.S in $(OUTPUT).

Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 tools/testing/selftests/powerpc/switch_endian/Makefile | 1 +
 1 file changed, 1 insertion(+)

diff --git a/tools/testing/selftests/powerpc/switch_endian/Makefile b/tools/testing/selftests/powerpc/switch_endian/Makefile
index 30b8ff8fb82e7..e4cedfe9753d7 100644
--- a/tools/testing/selftests/powerpc/switch_endian/Makefile
+++ b/tools/testing/selftests/powerpc/switch_endian/Makefile
@@ -7,6 +7,7 @@ EXTRA_CLEAN = $(OUTPUT)/*.o $(OUTPUT)/check-reversed.S
 
 include ../../lib.mk
 
+$(OUTPUT)/switch_endian_test: ASFLAGS += -I $(OUTPUT)
 $(OUTPUT)/switch_endian_test: $(OUTPUT)/check-reversed.S
 
 $(OUTPUT)/check-reversed.o: $(OUTPUT)/check.o
-- 
2.20.1

[PATCH AUTOSEL 4.14 092/150] selftests/powerpc/cache_shape: Fix out-of-tree build

[Sasha Levin]

From: Michael Ellerman <mpe@ellerman.id.au>

[ Upstream commit 69f8117f17b332a68cd8f4bf8c2d0d3d5b84efc5 ]

Use TEST_GEN_PROGS and don't redefine all, this makes the out-of-tree
build work. We need to move the extra dependencies below the include
of lib.mk, because it adds the $(OUTPUT) prefix if it's defined.

We can also drop the clean rule, lib.mk does it for us.

Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 tools/testing/selftests/powerpc/cache_shape/Makefile | 9 ++-------
 1 file changed, 2 insertions(+), 7 deletions(-)

diff --git a/tools/testing/selftests/powerpc/cache_shape/Makefile b/tools/testing/selftests/powerpc/cache_shape/Makefile
index 1be547434a49c..7e0c175b82978 100644
--- a/tools/testing/selftests/powerpc/cache_shape/Makefile
+++ b/tools/testing/selftests/powerpc/cache_shape/Makefile
@@ -1,11 +1,6 @@
 # SPDX-License-Identifier: GPL-2.0
-TEST_PROGS := cache_shape
-
-all: $(TEST_PROGS)
-
-$(TEST_PROGS): ../harness.c ../utils.c
+TEST_GEN_PROGS := cache_shape
 
 include ../../lib.mk
 
-clean:
-	rm -f $(TEST_PROGS) *.o
+$(TEST_GEN_PROGS): ../harness.c ../utils.c
-- 
2.20.1

[PATCH AUTOSEL 4.14 104/150] mm/memory_hotplug: make add_memory() take the device_hotplug_lock

[Sasha Levin]

From: David Hildenbrand <david@redhat.com>

[ Upstream commit 8df1d0e4a265f25dc1e7e7624ccdbcb4a6630c89 ]

add_memory() currently does not take the device_hotplug_lock, however
is aleady called under the lock from
	arch/powerpc/platforms/pseries/hotplug-memory.c
	drivers/acpi/acpi_memhotplug.c
to synchronize against CPU hot-remove and similar.

In general, we should hold the device_hotplug_lock when adding memory to
synchronize against online/offline request (e.g.  from user space) - which
already resulted in lock inversions due to device_lock() and
mem_hotplug_lock - see 30467e0b3be ("mm, hotplug: fix concurrent memory
hot-add deadlock").  add_memory()/add_memory_resource() will create memory
block devices, so this really feels like the right thing to do.

Holding the device_hotplug_lock makes sure that a memory block device
can really only be accessed (e.g. via .online/.state) from user space,
once the memory has been fully added to the system.

The lock is not held yet in
	drivers/xen/balloon.c
	arch/powerpc/platforms/powernv/memtrace.c
	drivers/s390/char/sclp_cmd.c
	drivers/hv/hv_balloon.c
So, let's either use the locked variants or take the lock.

Don't export add_memory_resource(), as it once was exported to be used by
XEN, which is never built as a module.  If somebody requires it, we also
have to export a locked variant (as device_hotplug_lock is never
exported).

Link: http://lkml.kernel.org/r/20180925091457.28651-3-david@redhat.com
Signed-off-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Pavel Tatashin <pavel.tatashin@microsoft.com>
Reviewed-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Reviewed-by: Rashmica Gupta <rashmica.g@gmail.com>
Reviewed-by: Oscar Salvador <osalvador@suse.de>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net>
Cc: Len Brown <lenb@kernel.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Cc: Juergen Gross <jgross@suse.com>
Cc: Nathan Fontenot <nfont@linux.vnet.ibm.com>
Cc: John Allen <jallen@linux.vnet.ibm.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Mathieu Malaterre <malat@debian.org>
Cc: Pavel Tatashin <pavel.tatashin@microsoft.com>
Cc: YASUAKI ISHIMATSU <yasu.isimatu@gmail.com>
Cc: Balbir Singh <bsingharora@gmail.com>
Cc: Haiyang Zhang <haiyangz@microsoft.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Kate Stewart <kstewart@linuxfoundation.org>
Cc: "K. Y. Srinivasan" <kys@microsoft.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Michael Neuling <mikey@neuling.org>
Cc: Philippe Ombredanne <pombredanne@nexb.com>
Cc: Stephen Hemminger <sthemmin@microsoft.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 .../platforms/pseries/hotplug-memory.c        |  2 +-
 drivers/acpi/acpi_memhotplug.c                |  2 +-
 drivers/base/memory.c                         |  9 ++++++--
 drivers/xen/balloon.c                         |  3 +++
 include/linux/memory_hotplug.h                |  1 +
 mm/memory_hotplug.c                           | 22 ++++++++++++++++---
 6 files changed, 32 insertions(+), 7 deletions(-)

diff --git a/arch/powerpc/platforms/pseries/hotplug-memory.c b/arch/powerpc/platforms/pseries/hotplug-memory.c
index 93e09f108ca17..99a3cf51c5ba4 100644
--- a/arch/powerpc/platforms/pseries/hotplug-memory.c
+++ b/arch/powerpc/platforms/pseries/hotplug-memory.c
@@ -787,7 +787,7 @@ static int dlpar_add_lmb(struct of_drconf_cell *lmb)
 	nid = memory_add_physaddr_to_nid(lmb->base_addr);
 
 	/* Add the memory */
-	rc = add_memory(nid, lmb->base_addr, block_sz);
+	rc = __add_memory(nid, lmb->base_addr, block_sz);
 	if (rc) {
 		dlpar_remove_device_tree_lmb(lmb);
 		return rc;
diff --git a/drivers/acpi/acpi_memhotplug.c b/drivers/acpi/acpi_memhotplug.c
index 6b0d3ef7309cb..2ccfbb61ca899 100644
--- a/drivers/acpi/acpi_memhotplug.c
+++ b/drivers/acpi/acpi_memhotplug.c
@@ -228,7 +228,7 @@ static int acpi_memory_enable_device(struct acpi_memory_device *mem_device)
 		if (node < 0)
 			node = memory_add_physaddr_to_nid(info->start_addr);
 
-		result = add_memory(node, info->start_addr, info->length);
+		result = __add_memory(node, info->start_addr, info->length);
 
 		/*
 		 * If the memory block has been used by the kernel, add_memory()
diff --git a/drivers/base/memory.c b/drivers/base/memory.c
index c617e00f4361d..8e5818e735e2f 100644
--- a/drivers/base/memory.c
+++ b/drivers/base/memory.c
@@ -517,15 +517,20 @@ memory_probe_store(struct device *dev, struct device_attribute *attr,
 	if (phys_addr & ((pages_per_block << PAGE_SHIFT) - 1))
 		return -EINVAL;
 
+	ret = lock_device_hotplug_sysfs();
+	if (ret)
+		goto out;
+
 	nid = memory_add_physaddr_to_nid(phys_addr);
-	ret = add_memory(nid, phys_addr,
-			 MIN_MEMORY_BLOCK_SIZE * sections_per_block);
+	ret = __add_memory(nid, phys_addr,
+			   MIN_MEMORY_BLOCK_SIZE * sections_per_block);
 
 	if (ret)
 		goto out;
 
 	ret = count;
 out:
+	unlock_device_hotplug();
 	return ret;
 }
 
diff --git a/drivers/xen/balloon.c b/drivers/xen/balloon.c
index 7d521babc020b..71a6deeb4e714 100644
--- a/drivers/xen/balloon.c
+++ b/drivers/xen/balloon.c
@@ -356,7 +356,10 @@ static enum bp_state reserve_additional_memory(void)
 	 * callers drop the mutex before trying again.
 	 */
 	mutex_unlock(&balloon_mutex);
+	/* add_memory_resource() requires the device_hotplug lock */
+	lock_device_hotplug();
 	rc = add_memory_resource(nid, resource, memhp_auto_online);
+	unlock_device_hotplug();
 	mutex_lock(&balloon_mutex);
 
 	if (rc) {
diff --git a/include/linux/memory_hotplug.h b/include/linux/memory_hotplug.h
index 58e110aee7ab4..d36a029353915 100644
--- a/include/linux/memory_hotplug.h
+++ b/include/linux/memory_hotplug.h
@@ -316,6 +316,7 @@ static inline void remove_memory(int nid, u64 start, u64 size) {}
 
 extern int walk_memory_range(unsigned long start_pfn, unsigned long end_pfn,
 		void *arg, int (*func)(struct memory_block *, void *));
+extern int __add_memory(int nid, u64 start, u64 size);
 extern int add_memory(int nid, u64 start, u64 size);
 extern int add_memory_resource(int nid, struct resource *resource, bool online);
 extern int arch_add_memory(int nid, u64 start, u64 size, bool want_memblock);
diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
index c9d3a49bd4e20..4dfcee4a779f3 100644
--- a/mm/memory_hotplug.c
+++ b/mm/memory_hotplug.c
@@ -1110,7 +1110,12 @@ static int online_memory_block(struct memory_block *mem, void *arg)
 	return device_online(&mem->dev);
 }
 
-/* we are OK calling __meminit stuff here - we have CONFIG_MEMORY_HOTPLUG */
+/*
+ * NOTE: The caller must call lock_device_hotplug() to serialize hotplug
+ * and online/offline operations (triggered e.g. by sysfs).
+ *
+ * we are OK calling __meminit stuff here - we have CONFIG_MEMORY_HOTPLUG
+ */
 int __ref add_memory_resource(int nid, struct resource *res, bool online)
 {
 	u64 start, size;
@@ -1203,9 +1208,9 @@ int __ref add_memory_resource(int nid, struct resource *res, bool online)
 	mem_hotplug_done();
 	return ret;
 }
-EXPORT_SYMBOL_GPL(add_memory_resource);
 
-int __ref add_memory(int nid, u64 start, u64 size)
+/* requires device_hotplug_lock, see add_memory_resource() */
+int __ref __add_memory(int nid, u64 start, u64 size)
 {
 	struct resource *res;
 	int ret;
@@ -1219,6 +1224,17 @@ int __ref add_memory(int nid, u64 start, u64 size)
 		release_memory_resource(res);
 	return ret;
 }
+
+int add_memory(int nid, u64 start, u64 size)
+{
+	int rc;
+
+	lock_device_hotplug();
+	rc = __add_memory(nid, start, size);
+	unlock_device_hotplug();
+
+	return rc;
+}
 EXPORT_SYMBOL_GPL(add_memory);
 
 #ifdef CONFIG_MEMORY_HOTREMOVE
-- 
2.20.1