From: Vineet Gupta <Vineet.Gupta1@synopsys.com>
To: <linux-arch@vger.kernel.org>, <linux-kernel@vger.kernel.org>
Cc: <arnd@arndb.de>, <arc-linux-dev@synopsys.com>,
Vineet Gupta <Vineet.Gupta1@synopsys.com>
Subject: [PATCH 14/28] ARCv2: SMP: ARConnect debug/robustness
Date: Tue, 9 Jun 2015 17:18:14 +0530 [thread overview]
Message-ID: <1433850508-26317-15-git-send-email-vgupta@synopsys.com> (raw)
In-Reply-To: <1433850508-26317-1-git-send-email-vgupta@synopsys.com>
- Handle possible interrupt coalescing from MCIP
- chk if prev IPI ack before sending new
Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
---
arch/arc/Kconfig | 15 ++++++++++++---
arch/arc/kernel/mcip.c | 48 ++++++++++++++++++++++++++++++++++++++++++++----
arch/arc/kernel/smp.c | 20 ++++++++++++++++----
3 files changed, 72 insertions(+), 11 deletions(-)
diff --git a/arch/arc/Kconfig b/arch/arc/Kconfig
index 301525020af7..ef5ca5969eaf 100644
--- a/arch/arc/Kconfig
+++ b/arch/arc/Kconfig
@@ -448,9 +448,10 @@ menuconfig ARC_DBG
bool "ARC debugging"
default y
+if ARC_DBG
+
config ARC_DW2_UNWIND
bool "Enable DWARF specific kernel stack unwind"
- depends on ARC_DBG
default y
select KALLSYMS
help
@@ -464,18 +465,26 @@ config ARC_DW2_UNWIND
config ARC_DBG_TLB_PARANOIA
bool "Paranoia Checks in Low Level TLB Handlers"
- depends on ARC_DBG
default n
config ARC_DBG_TLB_MISS_COUNT
bool "Profile TLB Misses"
default n
select DEBUG_FS
- depends on ARC_DBG
help
Counts number of I and D TLB Misses and exports them via Debugfs
The counters can be cleared via Debugfs as well
+if SMP
+
+config ARC_IPI_DBG
+ bool "Debug Inter Core interrupts"
+ default n
+
+endif
+
+endif
+
config ARC_UBOOT_SUPPORT
bool "Support uboot arg Handling"
default n
diff --git a/arch/arc/kernel/mcip.c b/arch/arc/kernel/mcip.c
index e6ad6e64440a..35921c3ab394 100644
--- a/arch/arc/kernel/mcip.c
+++ b/arch/arc/kernel/mcip.c
@@ -33,27 +33,67 @@ void mcip_init_smp(unsigned int cpu)
static void mcip_ipi_send(int cpu)
{
unsigned long flags;
+ int ipi_was_pending;
+
+ /*
+ * NOTE: We must spin here if the other cpu hasn't yet
+ * serviced a previous message. This can burn lots
+ * of time, but we MUST follows this protocol or
+ * ipi messages can be lost!!!
+ * Also, we must release the lock in this loop because
+ * the other side may get to this same loop and not
+ * be able to ack -- thus causing deadlock.
+ */
+
+ do {
+ raw_spin_lock_irqsave(&mcip_lock, flags);
+ __mcip_cmd(CMD_INTRPT_READ_STATUS, cpu);
+ ipi_was_pending = read_aux_reg(ARC_REG_MCIP_READBACK);
+ if (ipi_was_pending == 0)
+ break; /* break out but keep lock */
+ raw_spin_unlock_irqrestore(&mcip_lock, flags);
+ } while (1);
- raw_spin_lock_irqsave(&mcip_lock, flags);
__mcip_cmd(CMD_INTRPT_GENERATE_IRQ, cpu);
raw_spin_unlock_irqrestore(&mcip_lock, flags);
+
+#ifdef CONFIG_ARC_IPI_DBG
+ if (ipi_was_pending)
+ pr_info("IPI ACK delayed from cpu %d\n", cpu);
+#endif
}
static void mcip_ipi_clear(int irq)
{
- unsigned int cpu;
+ unsigned int cpu, c;
unsigned long flags;
+ unsigned int __maybe_unused copy;
raw_spin_lock_irqsave(&mcip_lock, flags);
/* Who sent the IPI */
__mcip_cmd(CMD_INTRPT_CHECK_SOURCE, 0);
- cpu = read_aux_reg(ARC_REG_MCIP_READBACK); /* 1,2,4,8... */
+ copy = cpu = read_aux_reg(ARC_REG_MCIP_READBACK); /* 1,2,4,8... */
- __mcip_cmd(CMD_INTRPT_GENERATE_ACK, __ffs(cpu)); /* 0,1,2,3... */
+ /*
+ * In rare case, multiple concurrent IPIs sent to same target can
+ * possibly be coalesced by MCIP into 1 asserted IRQ, so @cpus can be
+ * "vectored" (multiple bits sets) as opposed to typical single bit
+ */
+ do {
+ c = __ffs(cpu); /* 0,1,2,3 */
+ __mcip_cmd(CMD_INTRPT_GENERATE_ACK, c);
+ cpu &= ~(1U << c);
+ } while (cpu);
raw_spin_unlock_irqrestore(&mcip_lock, flags);
+
+#ifdef CONFIG_ARC_IPI_DBG
+ if (c != __ffs(copy))
+ pr_info("IPIs from %x coalesced to %x\n",
+ copy, raw_smp_processor_id());
+#endif
}
volatile int wake_flag;
diff --git a/arch/arc/kernel/smp.c b/arch/arc/kernel/smp.c
index d07cb53d7641..be13d12420ba 100644
--- a/arch/arc/kernel/smp.c
+++ b/arch/arc/kernel/smp.c
@@ -278,8 +278,10 @@ static void ipi_cpu_stop(void)
machine_halt();
}
-static inline void __do_IPI(unsigned long msg)
+static inline int __do_IPI(unsigned long msg)
{
+ int rc = 0;
+
switch (msg) {
case IPI_RESCHEDULE:
scheduler_ipi();
@@ -294,8 +296,10 @@ static inline void __do_IPI(unsigned long msg)
break;
default:
- pr_warn("IPI with unexpected msg %ld\n", msg);
+ rc = 1;
}
+
+ return rc;
}
/*
@@ -305,6 +309,7 @@ static inline void __do_IPI(unsigned long msg)
irqreturn_t do_IPI(int irq, void *dev_id)
{
unsigned long pending;
+ unsigned long __maybe_unused copy;
pr_debug("IPI [%ld] received on cpu %d\n",
*this_cpu_ptr(&ipi_data), smp_processor_id());
@@ -316,11 +321,18 @@ irqreturn_t do_IPI(int irq, void *dev_id)
* "dequeue" the msg corresponding to this IPI (and possibly other
* piggybacked msg from elided IPIs: see ipi_send_msg_one() above)
*/
- pending = xchg(this_cpu_ptr(&ipi_data), 0);
+ copy = pending = xchg(this_cpu_ptr(&ipi_data), 0);
do {
unsigned long msg = __ffs(pending);
- __do_IPI(msg);
+ int rc;
+
+ rc = __do_IPI(msg);
+#ifdef CONFIG_ARC_IPI_DBG
+ /* IPI received but no valid @msg */
+ if (rc)
+ pr_info("IPI with bogus msg %ld in %ld\n", msg, copy);
+#endif
pending &= ~(1U << msg);
} while (pending);
--
1.9.1
WARNING: multiple messages have this Message-ID (diff)
From: Vineet Gupta <Vineet.Gupta1@synopsys.com>
To: linux-arch@vger.kernel.org, linux-kernel@vger.kernel.org
Cc: arnd@arndb.de, arc-linux-dev@synopsys.com,
Vineet Gupta <Vineet.Gupta1@synopsys.com>
Subject: [PATCH 14/28] ARCv2: SMP: ARConnect debug/robustness
Date: Tue, 9 Jun 2015 17:18:14 +0530 [thread overview]
Message-ID: <1433850508-26317-15-git-send-email-vgupta@synopsys.com> (raw)
In-Reply-To: <1433850508-26317-1-git-send-email-vgupta@synopsys.com>
- Handle possible interrupt coalescing from MCIP
- chk if prev IPI ack before sending new
Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
---
arch/arc/Kconfig | 15 ++++++++++++---
arch/arc/kernel/mcip.c | 48 ++++++++++++++++++++++++++++++++++++++++++++----
arch/arc/kernel/smp.c | 20 ++++++++++++++++----
3 files changed, 72 insertions(+), 11 deletions(-)
diff --git a/arch/arc/Kconfig b/arch/arc/Kconfig
index 301525020af7..ef5ca5969eaf 100644
--- a/arch/arc/Kconfig
+++ b/arch/arc/Kconfig
@@ -448,9 +448,10 @@ menuconfig ARC_DBG
bool "ARC debugging"
default y
+if ARC_DBG
+
config ARC_DW2_UNWIND
bool "Enable DWARF specific kernel stack unwind"
- depends on ARC_DBG
default y
select KALLSYMS
help
@@ -464,18 +465,26 @@ config ARC_DW2_UNWIND
config ARC_DBG_TLB_PARANOIA
bool "Paranoia Checks in Low Level TLB Handlers"
- depends on ARC_DBG
default n
config ARC_DBG_TLB_MISS_COUNT
bool "Profile TLB Misses"
default n
select DEBUG_FS
- depends on ARC_DBG
help
Counts number of I and D TLB Misses and exports them via Debugfs
The counters can be cleared via Debugfs as well
+if SMP
+
+config ARC_IPI_DBG
+ bool "Debug Inter Core interrupts"
+ default n
+
+endif
+
+endif
+
config ARC_UBOOT_SUPPORT
bool "Support uboot arg Handling"
default n
diff --git a/arch/arc/kernel/mcip.c b/arch/arc/kernel/mcip.c
index e6ad6e64440a..35921c3ab394 100644
--- a/arch/arc/kernel/mcip.c
+++ b/arch/arc/kernel/mcip.c
@@ -33,27 +33,67 @@ void mcip_init_smp(unsigned int cpu)
static void mcip_ipi_send(int cpu)
{
unsigned long flags;
+ int ipi_was_pending;
+
+ /*
+ * NOTE: We must spin here if the other cpu hasn't yet
+ * serviced a previous message. This can burn lots
+ * of time, but we MUST follows this protocol or
+ * ipi messages can be lost!!!
+ * Also, we must release the lock in this loop because
+ * the other side may get to this same loop and not
+ * be able to ack -- thus causing deadlock.
+ */
+
+ do {
+ raw_spin_lock_irqsave(&mcip_lock, flags);
+ __mcip_cmd(CMD_INTRPT_READ_STATUS, cpu);
+ ipi_was_pending = read_aux_reg(ARC_REG_MCIP_READBACK);
+ if (ipi_was_pending == 0)
+ break; /* break out but keep lock */
+ raw_spin_unlock_irqrestore(&mcip_lock, flags);
+ } while (1);
- raw_spin_lock_irqsave(&mcip_lock, flags);
__mcip_cmd(CMD_INTRPT_GENERATE_IRQ, cpu);
raw_spin_unlock_irqrestore(&mcip_lock, flags);
+
+#ifdef CONFIG_ARC_IPI_DBG
+ if (ipi_was_pending)
+ pr_info("IPI ACK delayed from cpu %d\n", cpu);
+#endif
}
static void mcip_ipi_clear(int irq)
{
- unsigned int cpu;
+ unsigned int cpu, c;
unsigned long flags;
+ unsigned int __maybe_unused copy;
raw_spin_lock_irqsave(&mcip_lock, flags);
/* Who sent the IPI */
__mcip_cmd(CMD_INTRPT_CHECK_SOURCE, 0);
- cpu = read_aux_reg(ARC_REG_MCIP_READBACK); /* 1,2,4,8... */
+ copy = cpu = read_aux_reg(ARC_REG_MCIP_READBACK); /* 1,2,4,8... */
- __mcip_cmd(CMD_INTRPT_GENERATE_ACK, __ffs(cpu)); /* 0,1,2,3... */
+ /*
+ * In rare case, multiple concurrent IPIs sent to same target can
+ * possibly be coalesced by MCIP into 1 asserted IRQ, so @cpus can be
+ * "vectored" (multiple bits sets) as opposed to typical single bit
+ */
+ do {
+ c = __ffs(cpu); /* 0,1,2,3 */
+ __mcip_cmd(CMD_INTRPT_GENERATE_ACK, c);
+ cpu &= ~(1U << c);
+ } while (cpu);
raw_spin_unlock_irqrestore(&mcip_lock, flags);
+
+#ifdef CONFIG_ARC_IPI_DBG
+ if (c != __ffs(copy))
+ pr_info("IPIs from %x coalesced to %x\n",
+ copy, raw_smp_processor_id());
+#endif
}
volatile int wake_flag;
diff --git a/arch/arc/kernel/smp.c b/arch/arc/kernel/smp.c
index d07cb53d7641..be13d12420ba 100644
--- a/arch/arc/kernel/smp.c
+++ b/arch/arc/kernel/smp.c
@@ -278,8 +278,10 @@ static void ipi_cpu_stop(void)
machine_halt();
}
-static inline void __do_IPI(unsigned long msg)
+static inline int __do_IPI(unsigned long msg)
{
+ int rc = 0;
+
switch (msg) {
case IPI_RESCHEDULE:
scheduler_ipi();
@@ -294,8 +296,10 @@ static inline void __do_IPI(unsigned long msg)
break;
default:
- pr_warn("IPI with unexpected msg %ld\n", msg);
+ rc = 1;
}
+
+ return rc;
}
/*
@@ -305,6 +309,7 @@ static inline void __do_IPI(unsigned long msg)
irqreturn_t do_IPI(int irq, void *dev_id)
{
unsigned long pending;
+ unsigned long __maybe_unused copy;
pr_debug("IPI [%ld] received on cpu %d\n",
*this_cpu_ptr(&ipi_data), smp_processor_id());
@@ -316,11 +321,18 @@ irqreturn_t do_IPI(int irq, void *dev_id)
* "dequeue" the msg corresponding to this IPI (and possibly other
* piggybacked msg from elided IPIs: see ipi_send_msg_one() above)
*/
- pending = xchg(this_cpu_ptr(&ipi_data), 0);
+ copy = pending = xchg(this_cpu_ptr(&ipi_data), 0);
do {
unsigned long msg = __ffs(pending);
- __do_IPI(msg);
+ int rc;
+
+ rc = __do_IPI(msg);
+#ifdef CONFIG_ARC_IPI_DBG
+ /* IPI received but no valid @msg */
+ if (rc)
+ pr_info("IPI with bogus msg %ld in %ld\n", msg, copy);
+#endif
pending &= ~(1U << msg);
} while (pending);
--
1.9.1
next prev parent reply other threads:[~2015-06-09 11:54 UTC|newest]
Thread overview: 109+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-06-09 11:48 [PATCH 00/28] ARCv2 port to Linux - (B) ISA / Core / platform support Vineet Gupta
2015-06-09 11:48 ` Vineet Gupta
2015-06-09 11:48 ` [PATCH 01/28] ARCv2: [intc] HS38 core interrupt controller Vineet Gupta
2015-06-09 11:48 ` Vineet Gupta
2015-06-09 11:48 ` [PATCH 02/28] ARCv2: Support for ARCv2 ISA and HS38x cores Vineet Gupta
2015-06-09 11:48 ` Vineet Gupta
2015-06-09 11:48 ` [PATCH 03/28] ARCv2: STAR 9000793984: Handle return from intr to Delay Slot Vineet Gupta
2015-06-09 11:48 ` Vineet Gupta
2015-06-09 11:48 ` [PATCH 04/28] ARCv2: STAR 9000808988: signals involving " Vineet Gupta
2015-06-09 11:48 ` Vineet Gupta
2015-06-09 11:48 ` [PATCH 05/28] ARCv2: STAR 9000814690: Really Re-enable interrupts to avoid deadlocks Vineet Gupta
2015-06-09 11:48 ` Vineet Gupta
2015-06-09 11:48 ` [PATCH 06/28] ARCv2: MMUv4: TLB programming Model changes Vineet Gupta
2015-06-09 11:48 ` Vineet Gupta
2015-06-09 11:48 ` [PATCH 07/28] ARCv2: MMUv4: cache programming model changes Vineet Gupta
2015-06-09 11:48 ` Vineet Gupta
2015-06-09 11:48 ` [PATCH 08/28] ARCv2: MMUv4: support aliasing icache config Vineet Gupta
2015-06-09 11:48 ` Vineet Gupta
2015-06-09 11:48 ` [PATCH 09/28] ARCv2: optimised string/mem lib routines Vineet Gupta
2015-06-09 11:48 ` Vineet Gupta
2015-06-09 11:48 ` [PATCH 10/28] ARCv2: Adhere to Zero Delay loop restriction Vineet Gupta
2015-06-09 11:48 ` Vineet Gupta
2015-06-09 11:48 ` [PATCH 11/28] ARCv2: extable: Enable sorting at build time Vineet Gupta
2015-06-09 11:48 ` Vineet Gupta
2015-06-24 5:51 ` Vineet Gupta
2015-06-24 5:51 ` Vineet Gupta
2015-06-29 20:38 ` David Daney
2015-06-30 4:41 ` Vineet Gupta
2015-06-30 4:41 ` Vineet Gupta
2015-06-09 11:48 ` [PATCH 12/28] ARCv2: clocksource: Introduce 64bit local RTC counter Vineet Gupta
2015-06-09 11:48 ` Vineet Gupta
2015-06-09 11:48 ` [PATCH 13/28] ARC: make plat_smp_ops weak to allow over-rides Vineet Gupta
2015-06-09 11:48 ` Vineet Gupta
2015-06-09 11:48 ` Vineet Gupta [this message]
2015-06-09 11:48 ` [PATCH 14/28] ARCv2: SMP: ARConnect debug/robustness Vineet Gupta
2015-06-09 11:48 ` [PATCH 15/28] ARCv2: SMP: clocksource: Enable Global Real Time counter Vineet Gupta
2015-06-09 11:48 ` Vineet Gupta
2015-06-09 11:48 ` [PATCH 16/28] ARCv2: SMP: intc: IDU 2nd level intc for dynamic IRQ distribution Vineet Gupta
2015-06-09 11:48 ` Vineet Gupta
2015-06-09 11:48 ` [PATCH 17/28] ARC: add compiler barrier to LLSC based cmpxchg Vineet Gupta
2015-06-09 11:48 ` Vineet Gupta
2015-06-09 12:23 ` Peter Zijlstra
2015-06-09 11:48 ` [PATCH 18/28] ARC: add smp barriers around atomics per memory-barrriers.txt Vineet Gupta
2015-06-09 11:48 ` Vineet Gupta
2015-06-09 12:30 ` Peter Zijlstra
2015-06-10 9:17 ` Vineet Gupta
2015-06-10 10:53 ` Peter Zijlstra
2015-06-11 13:03 ` Vineet Gupta
2015-06-12 12:15 ` [PATCH v2] ARC: add smp barriers around atomics per Documentation/atomic_ops.txt Vineet Gupta
2015-06-12 12:15 ` Vineet Gupta
2015-06-12 13:04 ` Peter Zijlstra
2015-06-12 13:16 ` Vineet Gupta
2015-06-09 11:48 ` [PATCH 19/28] arch: conditionally define smp_{mb,rmb,wmb} Vineet Gupta
2015-06-09 11:48 ` Vineet Gupta
2015-06-09 12:32 ` Peter Zijlstra
2015-06-09 11:48 ` [PATCH 20/28] ARCv2: barriers Vineet Gupta
2015-06-09 11:48 ` Vineet Gupta
2015-06-09 12:40 ` Peter Zijlstra
2015-06-10 9:34 ` Vineet Gupta
2015-06-10 10:58 ` Peter Zijlstra
2015-06-10 13:01 ` Will Deacon
2015-06-11 12:13 ` Vineet Gupta
2015-06-11 13:39 ` Will Deacon
2015-06-19 13:13 ` Vineet Gupta
2015-06-19 13:13 ` Vineet Gupta
2015-06-19 13:13 ` Vineet Gupta
2015-06-22 13:36 ` Will Deacon
2015-06-22 13:36 ` Will Deacon
2015-06-22 13:36 ` Will Deacon
2015-06-23 7:58 ` [PATCH v2 " Vineet Gupta
2015-06-23 7:58 ` Vineet Gupta
2015-06-23 8:49 ` Will Deacon
2015-06-23 9:03 ` Vineet Gupta
2015-06-23 9:26 ` Will Deacon
2015-06-23 9:52 ` [PATCH v3 22/28] " Vineet Gupta
2015-06-23 9:52 ` Vineet Gupta
2015-06-23 16:28 ` Will Deacon
2015-06-23 9:25 ` [PATCH v2 20/28] " Peter Zijlstra
2015-06-23 8:02 ` [PATCH " Vineet Gupta
2015-06-09 11:48 ` [PATCH 21/28] ARC: Reduce bitops lines of code using macros Vineet Gupta
2015-06-09 11:48 ` Vineet Gupta
2015-06-12 12:20 ` [PATCH v2] " Vineet Gupta
2015-06-12 12:20 ` Vineet Gupta
2015-06-12 13:05 ` Peter Zijlstra
2015-06-09 11:48 ` [PATCH 22/28] ARCv2: STAR 9000837815 workaround hardware exclusive transactions livelock Vineet Gupta
2015-06-09 11:48 ` Vineet Gupta
2015-06-09 12:35 ` Peter Zijlstra
2015-06-10 10:01 ` Vineet Gupta
2015-06-10 11:02 ` Peter Zijlstra
2015-06-19 9:55 ` [PATCH v2 " Vineet Gupta
2015-06-19 9:55 ` Vineet Gupta
2015-06-19 9:59 ` Will Deacon
2015-06-19 10:09 ` Vineet Gupta
2015-06-23 7:59 ` Vineet Gupta
2015-06-23 7:59 ` Vineet Gupta
2015-06-09 11:48 ` [PATCH 23/28] ARCv2: SLC: Handle explcit flush for DMA ops (w/o IO-coherency) Vineet Gupta
2015-06-09 11:48 ` Vineet Gupta
2015-06-09 11:48 ` [PATCH 24/28] ARCv2: All bits in place, allow ARCv2 builds Vineet Gupta
2015-06-09 11:48 ` Vineet Gupta
2015-06-09 11:48 ` [PATCH 25/28] ARCv2: [nsim*hs*] Support simulation platforms for HS38x cores Vineet Gupta
2015-06-09 11:48 ` Vineet Gupta
2015-06-09 11:48 ` Vineet Gupta
2015-06-09 11:48 ` [PATCH 26/28] ARC: [axs101] Prepare for AXS103 Vineet Gupta
2015-06-09 11:48 ` Vineet Gupta
2015-06-09 11:48 ` [PATCH 27/28] ARCv2: [axs103] Support ARC SDP FPGA platform for HS38x cores Vineet Gupta
2015-06-09 11:48 ` Vineet Gupta
2015-06-09 11:48 ` Vineet Gupta
2015-06-09 11:48 ` [PATCH 28/28] ARCv2: [vdk] dts files and defconfig for HS38 VDK Vineet Gupta
2015-06-09 11:48 ` Vineet Gupta
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