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* [PATCH 07/29] powerpc/hvcall: add token and codes for H_VASI_SIGNAL
From: Nathan Lynch @ 2020-10-30  1:17 UTC (permalink / raw)
  To: linuxppc-dev; +Cc: tyreld, ajd, mmc, cforno12, drt, brking
In-Reply-To: <20201030011805.1224603-1-nathanl@linux.ibm.com>

H_VASI_SIGNAL can be used by a partition to request cancellation of
its migration. To be used in future changes.

Signed-off-by: Nathan Lynch <nathanl@linux.ibm.com>
---
 arch/powerpc/include/asm/hvcall.h | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/arch/powerpc/include/asm/hvcall.h b/arch/powerpc/include/asm/hvcall.h
index c1fbccb04390..c98f5141e3fc 100644
--- a/arch/powerpc/include/asm/hvcall.h
+++ b/arch/powerpc/include/asm/hvcall.h
@@ -155,6 +155,14 @@
 #define H_VASI_RESUMED          5
 #define H_VASI_COMPLETED        6
 
+/* VASI signal codes. Only the Cancel code is valid for H_VASI_SIGNAL. */
+#define H_VASI_SIGNAL_CANCEL    1
+#define H_VASI_SIGNAL_ABORT     2
+#define H_VASI_SIGNAL_SUSPEND   3
+#define H_VASI_SIGNAL_COMPLETE  4
+#define H_VASI_SIGNAL_ENABLE    5
+#define H_VASI_SIGNAL_FAILOVER  6
+
 /* Each control block has to be on a 4K boundary */
 #define H_CB_ALIGNMENT          4096
 
@@ -261,6 +269,7 @@
 #define H_ADD_CONN		0x284
 #define H_DEL_CONN		0x288
 #define H_JOIN			0x298
+#define H_VASI_SIGNAL           0x2A0
 #define H_VASI_STATE            0x2A4
 #define H_VIOCTL		0x2A8
 #define H_ENABLE_CRQ		0x2B0
-- 
2.25.4


^ permalink raw reply related

* [PATCH 08/29] powerpc/pseries/mobility: don't error on absence of ibm, update-nodes
From: Nathan Lynch @ 2020-10-30  1:17 UTC (permalink / raw)
  To: linuxppc-dev; +Cc: tyreld, ajd, mmc, cforno12, drt, brking
In-Reply-To: <20201030011805.1224603-1-nathanl@linux.ibm.com>

Treat the absence of the ibm,update-nodes function as benign instead
of reporting an error. If the platform does not provide that facility,
it's not a problem for Linux.

Signed-off-by: Nathan Lynch <nathanl@linux.ibm.com>
---
 arch/powerpc/platforms/pseries/mobility.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/powerpc/platforms/pseries/mobility.c b/arch/powerpc/platforms/pseries/mobility.c
index b6de65cbfcd9..5bcb6e5cc0f2 100644
--- a/arch/powerpc/platforms/pseries/mobility.c
+++ b/arch/powerpc/platforms/pseries/mobility.c
@@ -261,7 +261,7 @@ int pseries_devicetree_update(s32 scope)
 
 	update_nodes_token = rtas_token("ibm,update-nodes");
 	if (update_nodes_token == RTAS_UNKNOWN_SERVICE)
-		return -EINVAL;
+		return 0;
 
 	rtas_buf = kzalloc(RTAS_DATA_BUF_SIZE, GFP_KERNEL);
 	if (!rtas_buf)
-- 
2.25.4


^ permalink raw reply related

* [PATCH 09/29] powerpc/pseries/mobility: add missing break to default case
From: Nathan Lynch @ 2020-10-30  1:17 UTC (permalink / raw)
  To: linuxppc-dev; +Cc: tyreld, ajd, mmc, cforno12, drt, brking
In-Reply-To: <20201030011805.1224603-1-nathanl@linux.ibm.com>

update_dt_node() has a switch statement where the default case lacks a
break statement.

Signed-off-by: Nathan Lynch <nathanl@linux.ibm.com>
---
 arch/powerpc/platforms/pseries/mobility.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/arch/powerpc/platforms/pseries/mobility.c b/arch/powerpc/platforms/pseries/mobility.c
index 5bcb6e5cc0f2..d85799b5464a 100644
--- a/arch/powerpc/platforms/pseries/mobility.c
+++ b/arch/powerpc/platforms/pseries/mobility.c
@@ -213,6 +213,7 @@ static int update_dt_node(__be32 phandle, s32 scope)
 				}
 
 				prop_data += vd;
+				break;
 			}
 
 			cond_resched();
-- 
2.25.4


^ permalink raw reply related

* [PATCH 10/29] powerpc/pseries/mobility: error message improvements
From: Nathan Lynch @ 2020-10-30  1:17 UTC (permalink / raw)
  To: linuxppc-dev; +Cc: tyreld, ajd, mmc, cforno12, drt, brking
In-Reply-To: <20201030011805.1224603-1-nathanl@linux.ibm.com>

- Convert printk(KERN_ERR) to pr_err().
- Include errno in property update failure message.
- Remove reference to "Post-mobility" from device tree update message:
  with pr_err() it will have a "mobility:" prefix.

Signed-off-by: Nathan Lynch <nathanl@linux.ibm.com>
---
 arch/powerpc/platforms/pseries/mobility.c | 7 +++----
 1 file changed, 3 insertions(+), 4 deletions(-)

diff --git a/arch/powerpc/platforms/pseries/mobility.c b/arch/powerpc/platforms/pseries/mobility.c
index d85799b5464a..ef8f5641e700 100644
--- a/arch/powerpc/platforms/pseries/mobility.c
+++ b/arch/powerpc/platforms/pseries/mobility.c
@@ -208,8 +208,8 @@ static int update_dt_node(__be32 phandle, s32 scope)
 				rc = update_dt_property(dn, &prop, prop_name,
 							vd, prop_data);
 				if (rc) {
-					printk(KERN_ERR "Could not update %s"
-					       " property\n", prop_name);
+					pr_err("updating %s property failed: %d\n",
+					       prop_name, rc);
 				}
 
 				prop_data += vd;
@@ -343,8 +343,7 @@ void post_mobility_fixup(void)
 
 	rc = pseries_devicetree_update(MIGRATION_SCOPE);
 	if (rc)
-		printk(KERN_ERR "Post-mobility device tree update "
-			"failed: %d\n", rc);
+		pr_err("device tree update failed: %d\n", rc);
 
 	cacheinfo_rebuild();
 
-- 
2.25.4


^ permalink raw reply related

* [PATCH 11/29] powerpc/pseries/mobility: use rtas_activate_firmware() on resume
From: Nathan Lynch @ 2020-10-30  1:17 UTC (permalink / raw)
  To: linuxppc-dev; +Cc: tyreld, ajd, mmc, cforno12, drt, brking
In-Reply-To: <20201030011805.1224603-1-nathanl@linux.ibm.com>

It's incorrect to abort post-suspend processing if
ibm,activate-firmware isn't available. Use rtas_activate_firmware(),
which logs this condition appropriately and allows us to proceed.

Signed-off-by: Nathan Lynch <nathanl@linux.ibm.com>
---
 arch/powerpc/platforms/pseries/mobility.c | 15 +--------------
 1 file changed, 1 insertion(+), 14 deletions(-)

diff --git a/arch/powerpc/platforms/pseries/mobility.c b/arch/powerpc/platforms/pseries/mobility.c
index ef8f5641e700..dc6abf164db7 100644
--- a/arch/powerpc/platforms/pseries/mobility.c
+++ b/arch/powerpc/platforms/pseries/mobility.c
@@ -312,21 +312,8 @@ int pseries_devicetree_update(s32 scope)
 void post_mobility_fixup(void)
 {
 	int rc;
-	int activate_fw_token;
 
-	activate_fw_token = rtas_token("ibm,activate-firmware");
-	if (activate_fw_token == RTAS_UNKNOWN_SERVICE) {
-		printk(KERN_ERR "Could not make post-mobility "
-		       "activate-fw call.\n");
-		return;
-	}
-
-	do {
-		rc = rtas_call(activate_fw_token, 0, 1, NULL);
-	} while (rtas_busy_delay(rc));
-
-	if (rc)
-		printk(KERN_ERR "Post-mobility activate-fw failed: %d\n", rc);
+	rtas_activate_firmware();
 
 	/*
 	 * We don't want CPUs to go online/offline while the device
-- 
2.25.4


^ permalink raw reply related

* [PATCH 12/29] powerpc/pseries/mobility: extract VASI session polling logic
From: Nathan Lynch @ 2020-10-30  1:17 UTC (permalink / raw)
  To: linuxppc-dev; +Cc: tyreld, ajd, mmc, cforno12, drt, brking
In-Reply-To: <20201030011805.1224603-1-nathanl@linux.ibm.com>

The behavior of rtas_ibm_suspend_me_unsafe() is to return -EAGAIN to
the caller until the specified VASI suspend session state makes the
transition from H_VASI_ENABLED to H_VASI_SUSPENDING. In the interest
of separating concerns to prepare for a new implementation of the
join/suspend sequence, extract VASI session polling logic into a
couple of local functions. Waiting for the session state to reach
H_VASI_SUSPENDING before calling rtas_ibm_suspend_me_unsafe() ensures
that we will never get an EAGAIN result necessitating a retry. No
user-visible change in behavior is intended.

Signed-off-by: Nathan Lynch <nathanl@linux.ibm.com>
---
 arch/powerpc/platforms/pseries/mobility.c | 76 +++++++++++++++++++++--
 1 file changed, 71 insertions(+), 5 deletions(-)

diff --git a/arch/powerpc/platforms/pseries/mobility.c b/arch/powerpc/platforms/pseries/mobility.c
index dc6abf164db7..1b8ae221b98a 100644
--- a/arch/powerpc/platforms/pseries/mobility.c
+++ b/arch/powerpc/platforms/pseries/mobility.c
@@ -345,6 +345,73 @@ void post_mobility_fixup(void)
 	return;
 }
 
+static int poll_vasi_state(u64 handle, unsigned long *res)
+{
+	unsigned long retbuf[PLPAR_HCALL_BUFSIZE];
+	long hvrc;
+	int ret;
+
+	hvrc = plpar_hcall(H_VASI_STATE, retbuf, handle);
+	switch (hvrc) {
+	case H_SUCCESS:
+		ret = 0;
+		*res = retbuf[0];
+		break;
+	case H_PARAMETER:
+		ret = -EINVAL;
+		break;
+	case H_FUNCTION:
+		ret = -EOPNOTSUPP;
+		break;
+	case H_HARDWARE:
+	default:
+		pr_err("unexpected H_VASI_STATE result %ld\n", hvrc);
+		ret = -EIO;
+		break;
+	}
+	return ret;
+}
+
+static int wait_for_vasi_session_suspending(u64 handle)
+{
+	unsigned long state;
+	bool keep_polling;
+	int ret;
+
+	/*
+	 * Wait for transition from H_VASI_ENABLED to
+	 * H_VASI_SUSPENDING. Treat anything else as an error.
+	 */
+	do {
+		keep_polling = false;
+		ret = poll_vasi_state(handle, &state);
+		if (ret != 0)
+			break;
+
+		switch (state) {
+		case H_VASI_SUSPENDING:
+			break;
+		case H_VASI_ENABLED:
+			keep_polling = true;
+			ssleep(1);
+			break;
+		default:
+			pr_err("unexpected H_VASI_STATE result %lu\n", state);
+			ret = -EIO;
+			break;
+		}
+	} while (keep_polling);
+
+	/*
+	 * Proceed even if H_VASI_STATE is unavailable. If H_JOIN or
+	 * ibm,suspend-me are also unimplemented, we'll recover then.
+	 */
+	if (ret == -EOPNOTSUPP)
+		ret = 0;
+
+	return ret;
+}
+
 static ssize_t migration_store(struct class *class,
 			       struct class_attribute *attr, const char *buf,
 			       size_t count)
@@ -356,12 +423,11 @@ static ssize_t migration_store(struct class *class,
 	if (rc)
 		return rc;
 
-	do {
-		rc = rtas_ibm_suspend_me_unsafe(streamid);
-		if (rc == -EAGAIN)
-			ssleep(1);
-	} while (rc == -EAGAIN);
+	rc = wait_for_vasi_session_suspending(streamid);
+	if (rc)
+		return rc;
 
+	rc = rtas_ibm_suspend_me_unsafe(streamid);
 	if (rc)
 		return rc;
 
-- 
2.25.4


^ permalink raw reply related

* [PATCH 13/29] powerpc/pseries/mobility: use stop_machine for join/suspend
From: Nathan Lynch @ 2020-10-30  1:17 UTC (permalink / raw)
  To: linuxppc-dev; +Cc: tyreld, ajd, mmc, cforno12, drt, brking
In-Reply-To: <20201030011805.1224603-1-nathanl@linux.ibm.com>

The partition suspend sequence as specified in the platform
architecture requires that all active processor threads call
H_JOIN, which:

- suspends the calling thread until it is the target of
  an H_PROD; or
- immediately returns H_CONTINUE, if the calling thread is the last to
  call H_JOIN. This thread is expected to call ibm,suspend-me to
  completely suspend the partition.

Upon returning from ibm,suspend-me the calling thread must wake all
others using H_PROD.

rtas_ibm_suspend_me_unsafe() uses on_each_cpu() to implement this
protocol, but because of its synchronizing nature this is susceptible
to deadlock versus users of stop_machine() or other callers of
on_each_cpu().

Not only is stop_machine() intended for use cases like this, it
handles error propagation and allows us to keep the data shared
between CPUs minimal: a single atomic counter which ensures exactly
one CPU will wake the others from their joined states.

Switch the migration code to use stop_machine() and a less complex
local implementation of the H_JOIN/ibm,suspend-me logic, which
carries additional benefits:

- more informative error reporting, appropriately ratelimited
- resets the lockup detector / watchdog on resume to prevent lockup
  warnings when the OS has been suspended for a time exceeding the
  threshold.

Fixes: 91dc182ca6e2 ("[PATCH] powerpc: special-case ibm,suspend-me RTAS call")
Signed-off-by: Nathan Lynch <nathanl@linux.ibm.com>
---
 arch/powerpc/platforms/pseries/mobility.c | 132 ++++++++++++++++++++--
 1 file changed, 125 insertions(+), 7 deletions(-)

diff --git a/arch/powerpc/platforms/pseries/mobility.c b/arch/powerpc/platforms/pseries/mobility.c
index 1b8ae221b98a..44ca7d4e143d 100644
--- a/arch/powerpc/platforms/pseries/mobility.c
+++ b/arch/powerpc/platforms/pseries/mobility.c
@@ -12,9 +12,11 @@
 #include <linux/cpu.h>
 #include <linux/kernel.h>
 #include <linux/kobject.h>
+#include <linux/nmi.h>
 #include <linux/sched.h>
 #include <linux/smp.h>
 #include <linux/stat.h>
+#include <linux/stop_machine.h>
 #include <linux/completion.h>
 #include <linux/device.h>
 #include <linux/delay.h>
@@ -412,6 +414,128 @@ static int wait_for_vasi_session_suspending(u64 handle)
 	return ret;
 }
 
+static void prod_single(unsigned int target_cpu)
+{
+	long hvrc;
+	int hwid;
+
+	hwid = get_hard_smp_processor_id(target_cpu);
+	hvrc = plpar_hcall_norets(H_PROD, hwid);
+	if (hvrc == H_SUCCESS)
+		return;
+	pr_err_ratelimited("H_PROD of CPU %u (hwid %d) error: %ld\n",
+			   target_cpu, hwid, hvrc);
+}
+
+static void prod_others(void)
+{
+	unsigned int cpu;
+
+	for_each_online_cpu(cpu) {
+		if (cpu != smp_processor_id())
+			prod_single(cpu);
+	}
+}
+
+static u16 clamp_slb_size(void)
+{
+	u16 prev = mmu_slb_size;
+
+	slb_set_size(SLB_MIN_SIZE);
+
+	return prev;
+}
+
+static int do_suspend(void)
+{
+	u16 saved_slb_size;
+	int status;
+	int ret;
+
+	pr_info("calling ibm,suspend-me on CPU %i\n", smp_processor_id());
+
+	/*
+	 * The destination processor model may have fewer SLB entries
+	 * than the source. We reduce mmu_slb_size to a safe minimum
+	 * before suspending in order to minimize the possibility of
+	 * programming non-existent entries on the destination. If
+	 * suspend fails, we restore it before returning. On success
+	 * the OF reconfig path will update it from the new device
+	 * tree after resuming on the destination.
+	 */
+	saved_slb_size = clamp_slb_size();
+
+	ret = rtas_ibm_suspend_me(&status);
+	if (ret != 0) {
+		pr_err("ibm,suspend-me error: %d\n", status);
+		slb_set_size(saved_slb_size);
+	}
+
+	return ret;
+}
+
+static int do_join(void *arg)
+{
+	atomic_t *counter = arg;
+	long hvrc;
+	int ret;
+
+	/* Must ensure MSR.EE off for H_JOIN. */
+	hard_irq_disable();
+	hvrc = plpar_hcall_norets(H_JOIN);
+
+	switch (hvrc) {
+	case H_CONTINUE:
+		/*
+		 * All other CPUs are offline or in H_JOIN. This CPU
+		 * attempts the suspend.
+		 */
+		ret = do_suspend();
+		break;
+	case H_SUCCESS:
+		/*
+		 * The suspend is complete and this cpu has received a
+		 * prod.
+		 */
+		ret = 0;
+		break;
+	case H_BAD_MODE:
+	case H_HARDWARE:
+	default:
+		ret = -EIO;
+		pr_err_ratelimited("H_JOIN error %ld on CPU %i\n",
+				   hvrc, smp_processor_id());
+		break;
+	}
+
+	if (atomic_inc_return(counter) == 1) {
+		pr_info("CPU %u waking all threads\n", smp_processor_id());
+		prod_others();
+	}
+	/*
+	 * Execution may have been suspended for several seconds, so
+	 * reset the watchdog.
+	 */
+	touch_nmi_watchdog();
+	return ret;
+}
+
+static int pseries_migrate_partition(u64 handle)
+{
+	atomic_t counter = ATOMIC_INIT(0);
+	int ret;
+
+	ret = wait_for_vasi_session_suspending(handle);
+	if (ret)
+		goto out;
+
+	ret = stop_machine(do_join, &counter, cpu_online_mask);
+	if (ret == 0)
+		post_mobility_fixup();
+out:
+	return ret;
+}
+
 static ssize_t migration_store(struct class *class,
 			       struct class_attribute *attr, const char *buf,
 			       size_t count)
@@ -423,16 +547,10 @@ static ssize_t migration_store(struct class *class,
 	if (rc)
 		return rc;
 
-	rc = wait_for_vasi_session_suspending(streamid);
+	rc = pseries_migrate_partition(streamid);
 	if (rc)
 		return rc;
 
-	rc = rtas_ibm_suspend_me_unsafe(streamid);
-	if (rc)
-		return rc;
-
-	post_mobility_fixup();
-
 	return count;
 }
 
-- 
2.25.4


^ permalink raw reply related

* [PATCH 14/29] powerpc/pseries/mobility: signal suspend cancellation to platform
From: Nathan Lynch @ 2020-10-30  1:17 UTC (permalink / raw)
  To: linuxppc-dev; +Cc: tyreld, ajd, mmc, cforno12, drt, brking
In-Reply-To: <20201030011805.1224603-1-nathanl@linux.ibm.com>

If we're returning an error to user space, use H_VASI_SIGNAL to send a
cancellation request to the platform. This isn't strictly required but
it communicates that Linux will not attempt to complete the suspend,
which allows the various entities involved to promptly end the
operation in progress.

Signed-off-by: Nathan Lynch <nathanl@linux.ibm.com>
---
 arch/powerpc/platforms/pseries/mobility.c | 31 +++++++++++++++++++++++
 1 file changed, 31 insertions(+)

diff --git a/arch/powerpc/platforms/pseries/mobility.c b/arch/powerpc/platforms/pseries/mobility.c
index 44ca7d4e143d..0f592246f345 100644
--- a/arch/powerpc/platforms/pseries/mobility.c
+++ b/arch/powerpc/platforms/pseries/mobility.c
@@ -520,6 +520,35 @@ static int do_join(void *arg)
 	return ret;
 }
 
+/*
+ * Abort reason code byte 0. We use only the 'Migrating partition' value.
+ */
+enum vasi_aborting_entity {
+	ORCHESTRATOR        = 1,
+	VSP_SOURCE          = 2,
+	PARTITION_FIRMWARE  = 3,
+	PLATFORM_FIRMWARE   = 4,
+	VSP_TARGET          = 5,
+	MIGRATING_PARTITION = 6,
+};
+
+static void pseries_cancel_migration(u64 handle, int err)
+{
+	u32 reason_code;
+	u32 detail;
+	u8 entity;
+	long hvrc;
+
+	entity = MIGRATING_PARTITION;
+	detail = abs(err) & 0xffffff;
+	reason_code = (entity << 24) | detail;
+
+	hvrc = plpar_hcall_norets(H_VASI_SIGNAL, handle,
+				  H_VASI_SIGNAL_CANCEL, reason_code);
+	if (hvrc)
+		pr_err("H_VASI_SIGNAL error: %ld\n", hvrc);
+}
+
 static int pseries_migrate_partition(u64 handle)
 {
 	atomic_t counter = ATOMIC_INIT(0);
@@ -532,6 +561,8 @@ static int pseries_migrate_partition(u64 handle)
 	ret = stop_machine(do_join, &counter, cpu_online_mask);
 	if (ret == 0)
 		post_mobility_fixup();
+	else
+		pseries_cancel_migration(handle, ret);
 out:
 	return ret;
 }
-- 
2.25.4


^ permalink raw reply related

* [PATCH 16/29] powerpc/rtas: dispatch partition migration requests to pseries
From: Nathan Lynch @ 2020-10-30  1:17 UTC (permalink / raw)
  To: linuxppc-dev; +Cc: tyreld, ajd, mmc, cforno12, drt, brking
In-Reply-To: <20201030011805.1224603-1-nathanl@linux.ibm.com>

sys_rtas() cannot call ibm,suspend-me directly in the same way it
handles other inputs. Instead it must dispatch the request to code
that can first perform the H_JOIN sequence before any call to
ibm,suspend-me can succeed. Over time kernel/rtas.c has accreted a fair
amount of platform-specific code to implement this.

Since a different, more robust implementation of the suspend sequence
is now in the pseries platform code, we want to dispatch the request
there while minimizing additional dependence on pseries.

Use a weak function that only pseries overrides. Note that invoking
ibm,suspend-me via the RTAS syscall is all but deprecated; this change
preserves ABI compatibility for old programs while providing to them
the benefit of the new partition suspend implementation. This is a
behavior change in that the kernel performs the device tree update and
firmware activation before returning, but experimentation indicates
this is tolerated fine by legacy user space.

Signed-off-by: Nathan Lynch <nathanl@linux.ibm.com>
---
 arch/powerpc/include/asm/rtas.h           | 1 +
 arch/powerpc/kernel/rtas.c                | 8 +++++++-
 arch/powerpc/platforms/pseries/mobility.c | 5 +++++
 3 files changed, 13 insertions(+), 1 deletion(-)

diff --git a/arch/powerpc/include/asm/rtas.h b/arch/powerpc/include/asm/rtas.h
index fdefe6a974eb..be0fc2536673 100644
--- a/arch/powerpc/include/asm/rtas.h
+++ b/arch/powerpc/include/asm/rtas.h
@@ -260,6 +260,7 @@ extern int rtas_suspend_cpu(struct rtas_suspend_me_data *data);
 extern int rtas_suspend_last_cpu(struct rtas_suspend_me_data *data);
 int rtas_ibm_suspend_me_unsafe(u64 handle);
 int rtas_ibm_suspend_me(int *fw_status);
+int rtas_syscall_dispatch_ibm_suspend_me(u64 handle);
 
 struct rtc_time;
 extern time64_t rtas_get_boot_time(void);
diff --git a/arch/powerpc/kernel/rtas.c b/arch/powerpc/kernel/rtas.c
index 58bbd69a233f..52fb394f15d6 100644
--- a/arch/powerpc/kernel/rtas.c
+++ b/arch/powerpc/kernel/rtas.c
@@ -1221,6 +1221,12 @@ static bool block_rtas_call(int token, int nargs,
 
 #endif /* CONFIG_PPC_RTAS_FILTER */
 
+/* Only pseries should need to override this. */
+int __weak rtas_syscall_dispatch_ibm_suspend_me(u64 handle)
+{
+	return -EINVAL;
+}
+
 /* We assume to be passed big endian arguments */
 SYSCALL_DEFINE1(rtas, struct rtas_args __user *, uargs)
 {
@@ -1271,7 +1277,7 @@ SYSCALL_DEFINE1(rtas, struct rtas_args __user *, uargs)
 		int rc = 0;
 		u64 handle = ((u64)be32_to_cpu(args.args[0]) << 32)
 		              | be32_to_cpu(args.args[1]);
-		rc = rtas_ibm_suspend_me_unsafe(handle);
+		rc = rtas_syscall_dispatch_ibm_suspend_me(handle);
 		if (rc == -EAGAIN)
 			args.rets[0] = cpu_to_be32(RTAS_NOT_SUSPENDABLE);
 		else if (rc == -EIO)
diff --git a/arch/powerpc/platforms/pseries/mobility.c b/arch/powerpc/platforms/pseries/mobility.c
index e459cdb8286f..d6417c9db201 100644
--- a/arch/powerpc/platforms/pseries/mobility.c
+++ b/arch/powerpc/platforms/pseries/mobility.c
@@ -622,6 +622,11 @@ static int pseries_migrate_partition(u64 handle)
 	return ret;
 }
 
+int rtas_syscall_dispatch_ibm_suspend_me(u64 handle)
+{
+	return pseries_migrate_partition(handle);
+}
+
 static ssize_t migration_store(struct class *class,
 			       struct class_attribute *attr, const char *buf,
 			       size_t count)
-- 
2.25.4


^ permalink raw reply related

* [PATCH 19/29] powerpc/pseries/hibernation: pass stream id via function arguments
From: Nathan Lynch @ 2020-10-30  1:17 UTC (permalink / raw)
  To: linuxppc-dev; +Cc: tyreld, ajd, mmc, cforno12, drt, brking
In-Reply-To: <20201030011805.1224603-1-nathanl@linux.ibm.com>

There is no need for the stream id to be a file-global variable; pass
it from hibernate_store() to pseries_suspend_begin() for the
H_VASI_STATE call.

Signed-off-by: Nathan Lynch <nathanl@linux.ibm.com>
---
 arch/powerpc/platforms/pseries/suspend.c | 8 +++-----
 1 file changed, 3 insertions(+), 5 deletions(-)

diff --git a/arch/powerpc/platforms/pseries/suspend.c b/arch/powerpc/platforms/pseries/suspend.c
index 3eaa9d59dc7a..232621f33510 100644
--- a/arch/powerpc/platforms/pseries/suspend.c
+++ b/arch/powerpc/platforms/pseries/suspend.c
@@ -15,7 +15,6 @@
 #include <asm/topology.h>
 #include "../../kernel/cacheinfo.h"
 
-static u64 stream_id;
 static struct device suspend_dev;
 static DECLARE_COMPLETION(suspend_work);
 static struct rtas_suspend_me_data suspend_data;
@@ -29,7 +28,7 @@ static atomic_t suspending;
  * Return value:
  * 	0 on success / other on failure
  **/
-static int pseries_suspend_begin(suspend_state_t state)
+static int pseries_suspend_begin(u64 stream_id)
 {
 	long vasi_state, rc;
 	unsigned long retbuf[PLPAR_HCALL_BUFSIZE];
@@ -132,6 +131,7 @@ static ssize_t store_hibernate(struct device *dev,
 			       struct device_attribute *attr,
 			       const char *buf, size_t count)
 {
+	u64 stream_id;
 	int rc;
 
 	if (!capable(CAP_SYS_ADMIN))
@@ -140,7 +140,7 @@ static ssize_t store_hibernate(struct device *dev,
 	stream_id = simple_strtoul(buf, NULL, 16);
 
 	do {
-		rc = pseries_suspend_begin(PM_SUSPEND_MEM);
+		rc = pseries_suspend_begin(stream_id);
 		if (rc == -EAGAIN)
 			ssleep(1);
 	} while (rc == -EAGAIN);
@@ -148,8 +148,6 @@ static ssize_t store_hibernate(struct device *dev,
 	if (!rc)
 		rc = pm_suspend(PM_SUSPEND_MEM);
 
-	stream_id = 0;
-
 	if (!rc)
 		rc = count;
 
-- 
2.25.4


^ permalink raw reply related

* [PATCH 15/29] powerpc/pseries/mobility: retry partition suspend after error
From: Nathan Lynch @ 2020-10-30  1:17 UTC (permalink / raw)
  To: linuxppc-dev; +Cc: tyreld, ajd, mmc, cforno12, drt, brking
In-Reply-To: <20201030011805.1224603-1-nathanl@linux.ibm.com>

This is a mitigation for the relatively rare occurrence where a
virtual IOA can be in a transient state that prevents the
suspend/migration from succeeding, resulting in an error from
ibm,suspend-me.

If the join/suspend sequence returns an error, it is acceptable to
retry as long as the VASI suspend session state is still
"Suspending" (i.e. the platform is still waiting for the OS to
suspend).

Retry a few times on suspend failure while this condition holds,
progressively increasing the delay between attempts. We don't want to
retry indefinitey because firmware emits an error log event on each
unsuccessful attempt.

Signed-off-by: Nathan Lynch <nathanl@linux.ibm.com>
---
 arch/powerpc/platforms/pseries/mobility.c | 59 ++++++++++++++++++++++-
 1 file changed, 57 insertions(+), 2 deletions(-)

diff --git a/arch/powerpc/platforms/pseries/mobility.c b/arch/powerpc/platforms/pseries/mobility.c
index 0f592246f345..e459cdb8286f 100644
--- a/arch/powerpc/platforms/pseries/mobility.c
+++ b/arch/powerpc/platforms/pseries/mobility.c
@@ -549,16 +549,71 @@ static void pseries_cancel_migration(u64 handle, int err)
 		pr_err("H_VASI_SIGNAL error: %ld\n", hvrc);
 }
 
+static int pseries_suspend(u64 handle)
+{
+	const unsigned int max_attempts = 5;
+	unsigned int retry_interval_ms = 1;
+	unsigned int attempt = 1;
+	int ret;
+
+	while (true) {
+		atomic_t counter = ATOMIC_INIT(0);
+		unsigned long vasi_state;
+		int vasi_err;
+
+		ret = stop_machine(do_join, &counter, cpu_online_mask);
+		if (ret == 0)
+			break;
+		/*
+		 * Encountered an error. If the VASI stream is still
+		 * in Suspending state, it's likely a transient
+		 * condition related to some device in the partition
+		 * and we can retry in the hope that the cause has
+		 * cleared after some delay.
+		 *
+		 * A better design would allow drivers etc to prepare
+		 * for the suspend and avoid conditions which prevent
+		 * the suspend from succeeding. For now, we have this
+		 * mitigation.
+		 */
+		pr_notice("Partition suspend attempt %u of %u error: %d\n",
+			  attempt, max_attempts, ret);
+
+		if (attempt == max_attempts)
+			break;
+
+		vasi_err = poll_vasi_state(handle, &vasi_state);
+		if (vasi_err == 0) {
+			if (vasi_state != H_VASI_SUSPENDING) {
+				pr_notice("VASI state %lu after failed suspend\n",
+					  vasi_state);
+				break;
+			}
+		} else if (vasi_err != -EOPNOTSUPP) {
+			pr_err("VASI state poll error: %d", vasi_err);
+			break;
+		}
+
+		pr_notice("Will retry partition suspend after %u ms\n",
+			  retry_interval_ms);
+
+		msleep(retry_interval_ms);
+		retry_interval_ms *= 10;
+		attempt++;
+	}
+
+	return ret;
+}
+
 static int pseries_migrate_partition(u64 handle)
 {
-	atomic_t counter = ATOMIC_INIT(0);
 	int ret;
 
 	ret = wait_for_vasi_session_suspending(handle);
 	if (ret)
 		goto out;
 
-	ret = stop_machine(do_join, &counter, cpu_online_mask);
+	ret = pseries_suspend(handle);
 	if (ret == 0)
 		post_mobility_fixup();
 	else
-- 
2.25.4


^ permalink raw reply related

* [PATCH 17/29] powerpc/rtas: remove rtas_ibm_suspend_me_unsafe()
From: Nathan Lynch @ 2020-10-30  1:17 UTC (permalink / raw)
  To: linuxppc-dev; +Cc: tyreld, ajd, mmc, cforno12, drt, brking
In-Reply-To: <20201030011805.1224603-1-nathanl@linux.ibm.com>

rtas_ibm_suspend_me_unsafe() is now unused; remove it and
rtas_percpu_suspend_me() which becomes unused as a result.

Signed-off-by: Nathan Lynch <nathanl@linux.ibm.com>
---
 arch/powerpc/include/asm/rtas.h |  1 -
 arch/powerpc/kernel/rtas.c      | 64 ---------------------------------
 2 files changed, 65 deletions(-)

diff --git a/arch/powerpc/include/asm/rtas.h b/arch/powerpc/include/asm/rtas.h
index be0fc2536673..1e695e553a36 100644
--- a/arch/powerpc/include/asm/rtas.h
+++ b/arch/powerpc/include/asm/rtas.h
@@ -258,7 +258,6 @@ extern int rtas_set_indicator_fast(int indicator, int index, int new_value);
 extern void rtas_progress(char *s, unsigned short hex);
 extern int rtas_suspend_cpu(struct rtas_suspend_me_data *data);
 extern int rtas_suspend_last_cpu(struct rtas_suspend_me_data *data);
-int rtas_ibm_suspend_me_unsafe(u64 handle);
 int rtas_ibm_suspend_me(int *fw_status);
 int rtas_syscall_dispatch_ibm_suspend_me(u64 handle);
 
diff --git a/arch/powerpc/kernel/rtas.c b/arch/powerpc/kernel/rtas.c
index 52fb394f15d6..6fde38b488f7 100644
--- a/arch/powerpc/kernel/rtas.c
+++ b/arch/powerpc/kernel/rtas.c
@@ -895,70 +895,6 @@ int rtas_suspend_cpu(struct rtas_suspend_me_data *data)
 	return __rtas_suspend_cpu(data, 0);
 }
 
-static void rtas_percpu_suspend_me(void *info)
-{
-	__rtas_suspend_cpu((struct rtas_suspend_me_data *)info, 1);
-}
-
-int rtas_ibm_suspend_me_unsafe(u64 handle)
-{
-	long state;
-	long rc;
-	unsigned long retbuf[PLPAR_HCALL_BUFSIZE];
-	struct rtas_suspend_me_data data;
-	DECLARE_COMPLETION_ONSTACK(done);
-
-	if (!rtas_service_present("ibm,suspend-me"))
-		return -ENOSYS;
-
-	/* Make sure the state is valid */
-	rc = plpar_hcall(H_VASI_STATE, retbuf, handle);
-
-	state = retbuf[0];
-
-	if (rc) {
-		printk(KERN_ERR "rtas_ibm_suspend_me: vasi_state returned %ld\n",rc);
-		return rc;
-	} else if (state == H_VASI_ENABLED) {
-		return -EAGAIN;
-	} else if (state != H_VASI_SUSPENDING) {
-		printk(KERN_ERR "rtas_ibm_suspend_me: vasi_state returned state %ld\n",
-		       state);
-		return -EIO;
-	}
-
-	atomic_set(&data.working, 0);
-	atomic_set(&data.done, 0);
-	atomic_set(&data.error, 0);
-	data.token = rtas_token("ibm,suspend-me");
-	data.complete = &done;
-
-	lock_device_hotplug();
-
-	cpu_hotplug_disable();
-
-	/* Call function on all CPUs.  One of us will make the
-	 * rtas call
-	 */
-	on_each_cpu(rtas_percpu_suspend_me, &data, 0);
-
-	wait_for_completion(&done);
-
-	if (atomic_read(&data.error) != 0)
-		printk(KERN_ERR "Error doing global join\n");
-
-
-	cpu_hotplug_enable();
-
-	unlock_device_hotplug();
-
-	return atomic_read(&data.error);
-}
-#else /* CONFIG_PPC_PSERIES */
-int rtas_ibm_suspend_me_unsafe(u64 handle)
-{
-	return -ENOSYS;
-}
 #endif
 
 /**
-- 
2.25.4


^ permalink raw reply related

* [PATCH 20/29] powerpc/pseries/hibernation: remove pseries_suspend_cpu()
From: Nathan Lynch @ 2020-10-30  1:17 UTC (permalink / raw)
  To: linuxppc-dev; +Cc: tyreld, ajd, mmc, cforno12, drt, brking
In-Reply-To: <20201030011805.1224603-1-nathanl@linux.ibm.com>

Since commit 48f6e7f6d948 ("powerpc/pseries: remove cede offline state
for CPUs"), ppc_md.suspend_disable_cpu() is no longer used and all
CPUs (save one) are placed into true offline state as opposed to
H_JOIN. So pseries_suspend_cpu() is effectively unused; remove it.

Signed-off-by: Nathan Lynch <nathanl@linux.ibm.com>
---
 arch/powerpc/platforms/pseries/suspend.c | 15 ---------------
 1 file changed, 15 deletions(-)

diff --git a/arch/powerpc/platforms/pseries/suspend.c b/arch/powerpc/platforms/pseries/suspend.c
index 232621f33510..3315d698d5ab 100644
--- a/arch/powerpc/platforms/pseries/suspend.c
+++ b/arch/powerpc/platforms/pseries/suspend.c
@@ -48,20 +48,6 @@ static int pseries_suspend_begin(u64 stream_id)
 		       vasi_state);
 		return -EIO;
 	}
-
-	return 0;
-}
-
-/**
- * pseries_suspend_cpu - Suspend a single CPU
- *
- * Makes the H_JOIN call to suspend the CPU
- *
- **/
-static int pseries_suspend_cpu(void)
-{
-	if (atomic_read(&suspending))
-		return rtas_suspend_cpu(&suspend_data);
 	return 0;
 }
 
@@ -235,7 +221,6 @@ static int __init pseries_suspend_init(void)
 	if ((rc = pseries_suspend_sysfs_register(&suspend_dev)))
 		return rc;
 
-	ppc_md.suspend_disable_cpu = pseries_suspend_cpu;
 	ppc_md.suspend_enable_irqs = pseries_suspend_enable_irqs;
 	suspend_set_ops(&pseries_suspend_ops);
 	return 0;
-- 
2.25.4


^ permalink raw reply related

* [PATCH 21/29] powerpc/machdep: remove suspend_disable_cpu()
From: Nathan Lynch @ 2020-10-30  1:17 UTC (permalink / raw)
  To: linuxppc-dev; +Cc: tyreld, ajd, mmc, cforno12, drt, brking
In-Reply-To: <20201030011805.1224603-1-nathanl@linux.ibm.com>

There are no users left of the suspend_disable_cpu() callback, remove
it.

Signed-off-by: Nathan Lynch <nathanl@linux.ibm.com>
---
 arch/powerpc/include/asm/machdep.h | 1 -
 1 file changed, 1 deletion(-)

diff --git a/arch/powerpc/include/asm/machdep.h b/arch/powerpc/include/asm/machdep.h
index 475687f24f4a..cf6ebbc16cb4 100644
--- a/arch/powerpc/include/asm/machdep.h
+++ b/arch/powerpc/include/asm/machdep.h
@@ -207,7 +207,6 @@ struct machdep_calls {
 	void (*suspend_disable_irqs)(void);
 	void (*suspend_enable_irqs)(void);
 #endif
-	int (*suspend_disable_cpu)(void);
 
 #ifdef CONFIG_ARCH_CPU_PROBE_RELEASE
 	ssize_t (*cpu_probe)(const char *, size_t);
-- 
2.25.4


^ permalink raw reply related

* [PATCH 23/29] powerpc/pseries/hibernation: switch to rtas_ibm_suspend_me()
From: Nathan Lynch @ 2020-10-30  1:17 UTC (permalink / raw)
  To: linuxppc-dev; +Cc: tyreld, ajd, mmc, cforno12, drt, brking
In-Reply-To: <20201030011805.1224603-1-nathanl@linux.ibm.com>

rtas_suspend_last_cpu() and related code perform a lot of work that
isn't relevant to the hibernation workflow. All other CPUs are offline
when called so there is no need to place them in H_JOIN or prod them
on resume, nor is there need for retries or operations on shared
state.

Call the rtas_ibm_suspend_me() wrapper function directly from
pseries_suspend_enter() instead of using rtas_suspend_last_cpu().

Signed-off-by: Nathan Lynch <nathanl@linux.ibm.com>
---
 arch/powerpc/platforms/pseries/suspend.c | 6 +-----
 1 file changed, 1 insertion(+), 5 deletions(-)

diff --git a/arch/powerpc/platforms/pseries/suspend.c b/arch/powerpc/platforms/pseries/suspend.c
index 3315d698d5ab..703728cb95ec 100644
--- a/arch/powerpc/platforms/pseries/suspend.c
+++ b/arch/powerpc/platforms/pseries/suspend.c
@@ -76,11 +76,7 @@ static void pseries_suspend_enable_irqs(void)
  **/
 static int pseries_suspend_enter(suspend_state_t state)
 {
-	int rc = rtas_suspend_last_cpu(&suspend_data);
-
-	atomic_set(&suspending, 0);
-	atomic_set(&suspend_data.done, 1);
-	return rc;
+	return rtas_ibm_suspend_me(NULL);
 }
 
 /**
-- 
2.25.4


^ permalink raw reply related

* [PATCH 22/29] powerpc/rtas: remove rtas_suspend_cpu()
From: Nathan Lynch @ 2020-10-30  1:17 UTC (permalink / raw)
  To: linuxppc-dev; +Cc: tyreld, ajd, mmc, cforno12, drt, brking
In-Reply-To: <20201030011805.1224603-1-nathanl@linux.ibm.com>

rtas_suspend_cpu() no longer has users; remove it and
__rtas_suspend_cpu() which now becomes unused as well.

Signed-off-by: Nathan Lynch <nathanl@linux.ibm.com>
---
 arch/powerpc/include/asm/rtas.h |  1 -
 arch/powerpc/kernel/rtas.c      | 52 ---------------------------------
 2 files changed, 53 deletions(-)

diff --git a/arch/powerpc/include/asm/rtas.h b/arch/powerpc/include/asm/rtas.h
index 1e695e553a36..86f5d07969e4 100644
--- a/arch/powerpc/include/asm/rtas.h
+++ b/arch/powerpc/include/asm/rtas.h
@@ -256,7 +256,6 @@ extern bool rtas_indicator_present(int token, int *maxindex);
 extern int rtas_set_indicator(int indicator, int index, int new_value);
 extern int rtas_set_indicator_fast(int indicator, int index, int new_value);
 extern void rtas_progress(char *s, unsigned short hex);
-extern int rtas_suspend_cpu(struct rtas_suspend_me_data *data);
 extern int rtas_suspend_last_cpu(struct rtas_suspend_me_data *data);
 int rtas_ibm_suspend_me(int *fw_status);
 int rtas_syscall_dispatch_ibm_suspend_me(u64 handle);
diff --git a/arch/powerpc/kernel/rtas.c b/arch/powerpc/kernel/rtas.c
index 6fde38b488f7..4445219e92ce 100644
--- a/arch/powerpc/kernel/rtas.c
+++ b/arch/powerpc/kernel/rtas.c
@@ -843,58 +843,6 @@ int rtas_suspend_last_cpu(struct rtas_suspend_me_data *data)
 	return __rtas_suspend_last_cpu(data, 0);
 }
 
-static int __rtas_suspend_cpu(struct rtas_suspend_me_data *data, int wake_when_done)
-{
-	long rc = H_SUCCESS;
-	unsigned long msr_save;
-	int cpu;
-
-	atomic_inc(&data->working);
-
-	/* really need to ensure MSR.EE is off for H_JOIN */
-	msr_save = mfmsr();
-	mtmsr(msr_save & ~(MSR_EE));
-
-	while (rc == H_SUCCESS && !atomic_read(&data->done) && !atomic_read(&data->error))
-		rc = plpar_hcall_norets(H_JOIN);
-
-	mtmsr(msr_save);
-
-	if (rc == H_SUCCESS) {
-		/* This cpu was prodded and the suspend is complete. */
-		goto out;
-	} else if (rc == H_CONTINUE) {
-		/* All other cpus are in H_JOIN, this cpu does
-		 * the suspend.
-		 */
-		return __rtas_suspend_last_cpu(data, wake_when_done);
-	} else {
-		printk(KERN_ERR "H_JOIN on cpu %i failed with rc = %ld\n",
-		       smp_processor_id(), rc);
-		atomic_set(&data->error, rc);
-	}
-
-	if (wake_when_done) {
-		atomic_set(&data->done, 1);
-
-		/* This cpu did the suspend or got an error; in either case,
-		 * we need to prod all other other cpus out of join state.
-		 * Extra prods are harmless.
-		 */
-		for_each_online_cpu(cpu)
-			plpar_hcall_norets(H_PROD, get_hard_smp_processor_id(cpu));
-	}
-out:
-	if (atomic_dec_return(&data->working) == 0)
-		complete(data->complete);
-	return rc;
-}
-
-int rtas_suspend_cpu(struct rtas_suspend_me_data *data)
-{
-	return __rtas_suspend_cpu(data, 0);
-}
-
 #endif
 
 /**
-- 
2.25.4


^ permalink raw reply related

* [PATCH 24/29] powerpc/rtas: remove unused rtas_suspend_last_cpu()
From: Nathan Lynch @ 2020-10-30  1:18 UTC (permalink / raw)
  To: linuxppc-dev; +Cc: tyreld, ajd, mmc, cforno12, drt, brking
In-Reply-To: <20201030011805.1224603-1-nathanl@linux.ibm.com>

rtas_suspend_last_cpu() is now unused, remove it and
__rtas_suspend_last_cpu() which also becomes unused.

Signed-off-by: Nathan Lynch <nathanl@linux.ibm.com>
---
 arch/powerpc/include/asm/rtas.h |  1 -
 arch/powerpc/kernel/rtas.c      | 45 ---------------------------------
 2 files changed, 46 deletions(-)

diff --git a/arch/powerpc/include/asm/rtas.h b/arch/powerpc/include/asm/rtas.h
index 86f5d07969e4..d405b4bd659b 100644
--- a/arch/powerpc/include/asm/rtas.h
+++ b/arch/powerpc/include/asm/rtas.h
@@ -256,7 +256,6 @@ extern bool rtas_indicator_present(int token, int *maxindex);
 extern int rtas_set_indicator(int indicator, int index, int new_value);
 extern int rtas_set_indicator_fast(int indicator, int index, int new_value);
 extern void rtas_progress(char *s, unsigned short hex);
-extern int rtas_suspend_last_cpu(struct rtas_suspend_me_data *data);
 int rtas_ibm_suspend_me(int *fw_status);
 int rtas_syscall_dispatch_ibm_suspend_me(u64 handle);
 
diff --git a/arch/powerpc/kernel/rtas.c b/arch/powerpc/kernel/rtas.c
index 4445219e92ce..98ec9ffaa3b3 100644
--- a/arch/powerpc/kernel/rtas.c
+++ b/arch/powerpc/kernel/rtas.c
@@ -799,51 +799,6 @@ void rtas_os_term(char *str)
 }
 
 static int ibm_suspend_me_token = RTAS_UNKNOWN_SERVICE;
-#ifdef CONFIG_PPC_PSERIES
-static int __rtas_suspend_last_cpu(struct rtas_suspend_me_data *data, int wake_when_done)
-{
-	u16 slb_size = mmu_slb_size;
-	int rc = H_MULTI_THREADS_ACTIVE;
-	int cpu;
-
-	slb_set_size(SLB_MIN_SIZE);
-	printk(KERN_DEBUG "calling ibm,suspend-me on cpu %i\n", smp_processor_id());
-
-	while (rc == H_MULTI_THREADS_ACTIVE && !atomic_read(&data->done) &&
-	       !atomic_read(&data->error))
-		rc = rtas_call(data->token, 0, 1, NULL);
-
-	if (rc || atomic_read(&data->error)) {
-		printk(KERN_DEBUG "ibm,suspend-me returned %d\n", rc);
-		slb_set_size(slb_size);
-	}
-
-	if (atomic_read(&data->error))
-		rc = atomic_read(&data->error);
-
-	atomic_set(&data->error, rc);
-	pSeries_coalesce_init();
-
-	if (wake_when_done) {
-		atomic_set(&data->done, 1);
-
-		for_each_online_cpu(cpu)
-			plpar_hcall_norets(H_PROD, get_hard_smp_processor_id(cpu));
-	}
-
-	if (atomic_dec_return(&data->working) == 0)
-		complete(data->complete);
-
-	return rc;
-}
-
-int rtas_suspend_last_cpu(struct rtas_suspend_me_data *data)
-{
-	atomic_inc(&data->working);
-	return __rtas_suspend_last_cpu(data, 0);
-}
-
-#endif
 
 /**
  * rtas_activate_firmware() - Activate a new version of firmware.
-- 
2.25.4


^ permalink raw reply related

* [PATCH 25/29] powerpc/pseries/hibernation: remove redundant cacheinfo update
From: Nathan Lynch @ 2020-10-30  1:18 UTC (permalink / raw)
  To: linuxppc-dev; +Cc: tyreld, ajd, mmc, cforno12, drt, brking
In-Reply-To: <20201030011805.1224603-1-nathanl@linux.ibm.com>

Partitions with cache nodes in the device tree can encounter the
following warning on resume:

CPU 0 already accounted in PowerPC,POWER9@0(Data)
WARNING: CPU: 0 PID: 3177 at arch/powerpc/kernel/cacheinfo.c:197 cacheinfo_cpu_online+0x640/0x820

These calls to cacheinfo_cpu_offline/online have been redundant since
commit e610a466d16a ("powerpc/pseries/mobility: rebuild cacheinfo
hierarchy post-migration").

Fixes: e610a466d16a ("powerpc/pseries/mobility: rebuild cacheinfo hierarchy post-migration")
Signed-off-by: Nathan Lynch <nathanl@linux.ibm.com>
---
 arch/powerpc/platforms/pseries/suspend.c | 3 ---
 1 file changed, 3 deletions(-)

diff --git a/arch/powerpc/platforms/pseries/suspend.c b/arch/powerpc/platforms/pseries/suspend.c
index 703728cb95ec..6a94cc0deb88 100644
--- a/arch/powerpc/platforms/pseries/suspend.c
+++ b/arch/powerpc/platforms/pseries/suspend.c
@@ -13,7 +13,6 @@
 #include <asm/mmu.h>
 #include <asm/rtas.h>
 #include <asm/topology.h>
-#include "../../kernel/cacheinfo.h"
 
 static struct device suspend_dev;
 static DECLARE_COMPLETION(suspend_work);
@@ -63,9 +62,7 @@ static void pseries_suspend_enable_irqs(void)
 	 * Update configuration which can be modified based on device tree
 	 * changes during resume.
 	 */
-	cacheinfo_cpu_offline(smp_processor_id());
 	post_mobility_fixup();
-	cacheinfo_cpu_online(smp_processor_id());
 }
 
 /**
-- 
2.25.4


^ permalink raw reply related

* [PATCH 28/29] powerpc/rtas: remove unused rtas_suspend_me_data
From: Nathan Lynch @ 2020-10-30  1:18 UTC (permalink / raw)
  To: linuxppc-dev; +Cc: tyreld, ajd, mmc, cforno12, drt, brking
In-Reply-To: <20201030011805.1224603-1-nathanl@linux.ibm.com>

All code which used this type has been removed.

Signed-off-by: Nathan Lynch <nathanl@linux.ibm.com>
---
 arch/powerpc/include/asm/rtas-types.h | 8 --------
 1 file changed, 8 deletions(-)

diff --git a/arch/powerpc/include/asm/rtas-types.h b/arch/powerpc/include/asm/rtas-types.h
index aa420561bc10..8df6235d64d1 100644
--- a/arch/powerpc/include/asm/rtas-types.h
+++ b/arch/powerpc/include/asm/rtas-types.h
@@ -23,14 +23,6 @@ struct rtas_t {
 	struct device_node *dev;	/* virtual address pointer */
 };
 
-struct rtas_suspend_me_data {
-	atomic_t working; /* number of cpus accessing this struct */
-	atomic_t done;
-	int token; /* ibm,suspend-me */
-	atomic_t error;
-	struct completion *complete; /* wait on this until working == 0 */
-};
-
 struct rtas_error_log {
 	/* Byte 0 */
 	u8		byte0;			/* Architectural version */
-- 
2.25.4


^ permalink raw reply related

* [PATCH 27/29] powerpc/pseries/hibernation: remove prepare_late() callback
From: Nathan Lynch @ 2020-10-30  1:18 UTC (permalink / raw)
  To: linuxppc-dev; +Cc: tyreld, ajd, mmc, cforno12, drt, brking
In-Reply-To: <20201030011805.1224603-1-nathanl@linux.ibm.com>

The pseries hibernate code no longer calls into the original
join/suspend code in kernel/rtas.c, so pseries_prepare_late() and
related code don't accomplish anything now.

Signed-off-by: Nathan Lynch <nathanl@linux.ibm.com>
---
 arch/powerpc/platforms/pseries/suspend.c | 25 ------------------------
 1 file changed, 25 deletions(-)

diff --git a/arch/powerpc/platforms/pseries/suspend.c b/arch/powerpc/platforms/pseries/suspend.c
index 589a91730db8..1b902cbf85c5 100644
--- a/arch/powerpc/platforms/pseries/suspend.c
+++ b/arch/powerpc/platforms/pseries/suspend.c
@@ -15,9 +15,6 @@
 #include <asm/topology.h>
 
 static struct device suspend_dev;
-static DECLARE_COMPLETION(suspend_work);
-static struct rtas_suspend_me_data suspend_data;
-static atomic_t suspending;
 
 /**
  * pseries_suspend_begin - First phase of hibernation
@@ -61,23 +58,6 @@ static int pseries_suspend_enter(suspend_state_t state)
 	return rtas_ibm_suspend_me(NULL);
 }
 
-/**
- * pseries_prepare_late - Prepare to suspend all other CPUs
- *
- * Return value:
- * 	0 on success / other on failure
- **/
-static int pseries_prepare_late(void)
-{
-	atomic_set(&suspending, 1);
-	atomic_set(&suspend_data.working, 0);
-	atomic_set(&suspend_data.done, 0);
-	atomic_set(&suspend_data.error, 0);
-	suspend_data.complete = &suspend_work;
-	reinit_completion(&suspend_work);
-	return 0;
-}
-
 /**
  * store_hibernate - Initiate partition hibernation
  * @dev:		subsys root device
@@ -152,7 +132,6 @@ static struct bus_type suspend_subsys = {
 
 static const struct platform_suspend_ops pseries_suspend_ops = {
 	.valid		= suspend_valid_only_mem,
-	.prepare_late	= pseries_prepare_late,
 	.enter		= pseries_suspend_enter,
 };
 
@@ -195,10 +174,6 @@ static int __init pseries_suspend_init(void)
 	if (!firmware_has_feature(FW_FEATURE_LPAR))
 		return 0;
 
-	suspend_data.token = rtas_token("ibm,suspend-me");
-	if (suspend_data.token == RTAS_UNKNOWN_SERVICE)
-		return 0;
-
 	if ((rc = pseries_suspend_sysfs_register(&suspend_dev)))
 		return rc;
 
-- 
2.25.4


^ permalink raw reply related

* [PATCH 29/29] powerpc/pseries/mobility: refactor node lookup during DT update
From: Nathan Lynch @ 2020-10-30  1:18 UTC (permalink / raw)
  To: linuxppc-dev; +Cc: tyreld, ajd, mmc, cforno12, drt, brking
In-Reply-To: <20201030011805.1224603-1-nathanl@linux.ibm.com>

In pseries_devicetree_update(), with each call to ibm,update-nodes the
partition firmware communicates the node to be deleted or updated by
placing its phandle in the work buffer. Each of delete_dt_node(),
update_dt_node(), and add_dt_node() have duplicate lookups using the
phandle value and corresponding refcount management.

Move the lookup and of_node_put() into pseries_devicetree_update(),
and emit a warning on any failed lookups.

Signed-off-by: Nathan Lynch <nathanl@linux.ibm.com>
---
 arch/powerpc/platforms/pseries/mobility.c | 45 ++++++++---------------
 1 file changed, 16 insertions(+), 29 deletions(-)

diff --git a/arch/powerpc/platforms/pseries/mobility.c b/arch/powerpc/platforms/pseries/mobility.c
index d6417c9db201..5521b63898aa 100644
--- a/arch/powerpc/platforms/pseries/mobility.c
+++ b/arch/powerpc/platforms/pseries/mobility.c
@@ -61,18 +61,10 @@ static int mobility_rtas_call(int token, char *buf, s32 scope)
 	return rc;
 }
 
-static int delete_dt_node(__be32 phandle)
+static int delete_dt_node(struct device_node *dn)
 {
-	struct device_node *dn;
-
-	dn = of_find_node_by_phandle(be32_to_cpu(phandle));
-	if (!dn)
-		return -ENOENT;
-
 	pr_debug("removing node %pOFfp\n", dn);
-
 	dlpar_detach_node(dn);
-	of_node_put(dn);
 	return 0;
 }
 
@@ -137,10 +129,9 @@ static int update_dt_property(struct device_node *dn, struct property **prop,
 	return 0;
 }
 
-static int update_dt_node(__be32 phandle, s32 scope)
+static int update_dt_node(struct device_node *dn, s32 scope)
 {
 	struct update_props_workarea *upwa;
-	struct device_node *dn;
 	struct property *prop = NULL;
 	int i, rc, rtas_rc;
 	char *prop_data;
@@ -157,14 +148,8 @@ static int update_dt_node(__be32 phandle, s32 scope)
 	if (!rtas_buf)
 		return -ENOMEM;
 
-	dn = of_find_node_by_phandle(be32_to_cpu(phandle));
-	if (!dn) {
-		kfree(rtas_buf);
-		return -ENOENT;
-	}
-
 	upwa = (struct update_props_workarea *)&rtas_buf[0];
-	upwa->phandle = phandle;
+	upwa->phandle = cpu_to_be32(dn->phandle);
 
 	do {
 		rtas_rc = mobility_rtas_call(update_properties_token, rtas_buf,
@@ -224,21 +209,15 @@ static int update_dt_node(__be32 phandle, s32 scope)
 		cond_resched();
 	} while (rtas_rc == 1);
 
-	of_node_put(dn);
 	kfree(rtas_buf);
 	return 0;
 }
 
-static int add_dt_node(__be32 parent_phandle, __be32 drc_index)
+static int add_dt_node(struct device_node *parent_dn, __be32 drc_index)
 {
 	struct device_node *dn;
-	struct device_node *parent_dn;
 	int rc;
 
-	parent_dn = of_find_node_by_phandle(be32_to_cpu(parent_phandle));
-	if (!parent_dn)
-		return -ENOENT;
-
 	dn = dlpar_configure_connector(drc_index, parent_dn);
 	if (!dn) {
 		of_node_put(parent_dn);
@@ -251,7 +230,6 @@ static int add_dt_node(__be32 parent_phandle, __be32 drc_index)
 
 	pr_debug("added node %pOFfp\n", dn);
 
-	of_node_put(parent_dn);
 	return rc;
 }
 
@@ -284,22 +262,31 @@ int pseries_devicetree_update(s32 scope)
 			data++;
 
 			for (i = 0; i < node_count; i++) {
+				struct device_node *np;
 				__be32 phandle = *data++;
 				__be32 drc_index;
 
+				np = of_find_node_by_phandle(be32_to_cpu(phandle));
+				if (!np) {
+					pr_warn("Failed lookup: phandle 0x%x for action 0x%x\n",
+						be32_to_cpu(phandle), action);
+					continue;
+				}
+
 				switch (action) {
 				case DELETE_DT_NODE:
-					delete_dt_node(phandle);
+					delete_dt_node(np);
 					break;
 				case UPDATE_DT_NODE:
-					update_dt_node(phandle, scope);
+					update_dt_node(np, scope);
 					break;
 				case ADD_DT_NODE:
 					drc_index = *data++;
-					add_dt_node(phandle, drc_index);
+					add_dt_node(np, drc_index);
 					break;
 				}
 
+				of_node_put(np);
 				cond_resched();
 			}
 		}
-- 
2.25.4


^ permalink raw reply related

* [PATCH 18/29] powerpc/pseries/hibernation: drop pseries_suspend_begin() from suspend ops
From: Nathan Lynch @ 2020-10-30  1:17 UTC (permalink / raw)
  To: linuxppc-dev; +Cc: tyreld, ajd, mmc, cforno12, drt, brking
In-Reply-To: <20201030011805.1224603-1-nathanl@linux.ibm.com>

There are three ways pseries_suspend_begin() can be reached:

1. When "mem" is written to /sys/power/state:

kobj_attr_store()
-> state_store()
  -> pm_suspend()
    -> suspend_devices_and_enter()
      -> pseries_suspend_begin()

This never works because there is no way to supply a valid stream id
using this interface, and H_VASI_STATE is called with a stream id of
zero. So this call path is useless at best.

2. When a stream id is written to /sys/devices/system/power/hibernate.
pseries_suspend_begin() is polled directly from store_hibernate()
until the stream is in the "Suspending" state (i.e. the platform is
ready for the OS to suspend execution):

dev_attr_store()
-> store_hibernate()
  -> pseries_suspend_begin()

3. When a stream id is written to /sys/devices/system/power/hibernate
(continued). After #2, pseries_suspend_begin() is called once again
from the pm core:

dev_attr_store()
-> store_hibernate()
  -> pm_suspend()
    -> suspend_devices_and_enter()
      -> pseries_suspend_begin()

This is redundant because the VASI suspend state is already known to
be Suspending.

The begin() callback of platform_suspend_ops is optional, so we can
simply remove that assignment with no loss of function.

Fixes: 32d8ad4e621d ("powerpc/pseries: Partition hibernation support")
Signed-off-by: Nathan Lynch <nathanl@linux.ibm.com>
---
 arch/powerpc/platforms/pseries/suspend.c | 1 -
 1 file changed, 1 deletion(-)

diff --git a/arch/powerpc/platforms/pseries/suspend.c b/arch/powerpc/platforms/pseries/suspend.c
index 81e0ac58d620..3eaa9d59dc7a 100644
--- a/arch/powerpc/platforms/pseries/suspend.c
+++ b/arch/powerpc/platforms/pseries/suspend.c
@@ -187,7 +187,6 @@ static struct bus_type suspend_subsys = {
 
 static const struct platform_suspend_ops pseries_suspend_ops = {
 	.valid		= suspend_valid_only_mem,
-	.begin		= pseries_suspend_begin,
 	.prepare_late	= pseries_prepare_late,
 	.enter		= pseries_suspend_enter,
 };
-- 
2.25.4


^ permalink raw reply related

* [PATCH 26/29] powerpc/pseries/hibernation: perform post-suspend fixups later
From: Nathan Lynch @ 2020-10-30  1:18 UTC (permalink / raw)
  To: linuxppc-dev; +Cc: tyreld, ajd, mmc, cforno12, drt, brking
In-Reply-To: <20201030011805.1224603-1-nathanl@linux.ibm.com>

The pseries hibernate code calls post_mobility_fixup() which is sort
of a dumping ground of fixups that need to run after resuming from
suspend regardless of whether suspend was a hibernation or a
migration. Calling post_mobility_fixup() from
pseries_suspend_enable_irqs() runs this code early in resume with
devices suspended and only one CPU up, while the much more commonly
used migration case runs these fixups in a more typical process
context.

Call post_mobility_fixup() after the suspend core returns a success
status to the hibernate sysfs store method and remove
pseries_suspend_enable_irqs().

Signed-off-by: Nathan Lynch <nathanl@linux.ibm.com>
---
 arch/powerpc/platforms/pseries/suspend.c | 21 ++++-----------------
 1 file changed, 4 insertions(+), 17 deletions(-)

diff --git a/arch/powerpc/platforms/pseries/suspend.c b/arch/powerpc/platforms/pseries/suspend.c
index 6a94cc0deb88..589a91730db8 100644
--- a/arch/powerpc/platforms/pseries/suspend.c
+++ b/arch/powerpc/platforms/pseries/suspend.c
@@ -50,21 +50,6 @@ static int pseries_suspend_begin(u64 stream_id)
 	return 0;
 }
 
-/**
- * pseries_suspend_enable_irqs
- *
- * Post suspend configuration updates
- *
- **/
-static void pseries_suspend_enable_irqs(void)
-{
-	/*
-	 * Update configuration which can be modified based on device tree
-	 * changes during resume.
-	 */
-	post_mobility_fixup();
-}
-
 /**
  * pseries_suspend_enter - Final phase of hibernation
  *
@@ -127,8 +112,11 @@ static ssize_t store_hibernate(struct device *dev,
 	if (!rc)
 		rc = pm_suspend(PM_SUSPEND_MEM);
 
-	if (!rc)
+	if (!rc) {
 		rc = count;
+		post_mobility_fixup();
+	}
+
 
 	return rc;
 }
@@ -214,7 +202,6 @@ static int __init pseries_suspend_init(void)
 	if ((rc = pseries_suspend_sysfs_register(&suspend_dev)))
 		return rc;
 
-	ppc_md.suspend_enable_irqs = pseries_suspend_enable_irqs;
 	suspend_set_ops(&pseries_suspend_ops);
 	return 0;
 }
-- 
2.25.4


^ permalink raw reply related

* Re: [PATCH] ibmvfc: add new fields for version 2 of several MADs
From: Martin K. Petersen @ 2020-10-30  1:57 UTC (permalink / raw)
  To: Tyrel Datwyler
  Cc: Martin K. Petersen, linux-scsi, linux-kernel, james.bottomley,
	brking, linuxppc-dev
In-Reply-To: <c94f0f87-1863-9c0a-3561-4cbc9330e011@linux.ibm.com>


Tyrel,

> I'm going to have to ask that this patch be unstaged.

Done!

-- 
Martin K. Petersen	Oracle Linux Engineering

^ permalink raw reply

* Re: [PATCH] powerpc: add support for TIF_NOTIFY_SIGNAL
From: Jens Axboe @ 2020-10-30  2:35 UTC (permalink / raw)
  To: Michael Ellerman, linuxppc-dev
In-Reply-To: <871rhgwnc1.fsf@mpe.ellerman.id.au>

On 10/29/20 6:48 PM, Michael Ellerman wrote:
> Jens Axboe <axboe@kernel.dk> writes:
>> Wire up TIF_NOTIFY_SIGNAL handling for powerpc.
>>
>> Cc: linuxppc-dev@lists.ozlabs.org
>> Signed-off-by: Jens Axboe <axboe@kernel.dk>
>> ---
>>
>> 5.11 has support queued up for TIF_NOTIFY_SIGNAL, see this posting
>> for details:
>>
>> https://lore.kernel.org/io-uring/20201026203230.386348-1-axboe@kernel.dk/
>>
>> As part of that work, I'm adding TIF_NOTIFY_SIGNAL support to all archs,
>> as that will enable a set of cleanups once all of them support it. I'm
>> happy carrying this patch if need be, or it can be funelled through the
>> arch tree. Let me know.
> 
> Happy for you to take it along with the rest of the series.
> 
> Acked-by: Michael Ellerman <mpe@ellerman.id.au>

Great, thanks Michael! Added.

-- 
Jens Axboe


^ permalink raw reply


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