[PATCH AUTOSEL 4.9 05/99] powerpc: Fix signedness bug in update_flash_db()

[PATCH AUTOSEL 4.9 05/99] 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 4.9 06/99] 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 1abd8dd77ec13..eee2131a97e61 100644
--- a/arch/powerpc/kernel/eeh_pe.c
+++ b/arch/powerpc/kernel/eeh_pe.c
@@ -370,7 +370,7 @@ 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 4.9 30/99] 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 ad6223e883404..3d310dd60a0be 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 4.9 50/99] 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 47c6c0401b3a2..54c95e7c74cce 100644
--- a/arch/powerpc/kernel/process.c
+++ b/arch/powerpc/kernel/process.c
@@ -576,12 +576,11 @@ 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 4.9 68/99] 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 c0a0947f43bbb..656bbbd731d03 100644
--- a/arch/powerpc/platforms/pseries/hotplug-memory.c
+++ b/arch/powerpc/platforms/pseries/hotplug-memory.c
@@ -616,7 +616,7 @@ 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);
 		dlpar_release_drc(lmb->drc_index);
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 c5cdd190b7816..9f96f1b43c15f 100644
--- a/drivers/base/memory.c
+++ b/drivers/base/memory.c
@@ -500,15 +500,20 @@ 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 6af117af97804..731cf54f75c65 100644
--- a/drivers/xen/balloon.c
+++ b/drivers/xen/balloon.c
@@ -358,7 +358,10 @@ 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 134a2f69c21ab..9469eef300952 100644
--- a/include/linux/memory_hotplug.h
+++ b/include/linux/memory_hotplug.h
@@ -272,6 +272,7 @@ 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 zone_for_memory(int nid, u64 start, u64 size, int zone_default,
diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
index b4c8d7b9ab820..449999657c0bb 100644
--- a/mm/memory_hotplug.c
+++ b/mm/memory_hotplug.c
@@ -1340,7 +1340,12 @@ static int online_memory_block(struct memory_block *mem, void *arg)
 	return memory_block_change_state(mem, MEM_ONLINE, MEM_OFFLINE);
 }
 
-/* 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;
@@ -1418,9 +1423,9 @@ 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;
@@ -1434,6 +1439,17 @@ 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