[tip:x86/platform] x86/platform/UV: Add Support for UV4 Hubless NMIs

From: tip-bot for travis@xxxxxxx
Date: Wed Feb 01 2017 - 05:11:05 EST

Commit-ID: abdf1df6bc0416ec19b841e92b497ca55b23454c
Gitweb: http://git.kernel.org/tip/abdf1df6bc0416ec19b841e92b497ca55b23454c
Author: travis@xxxxxxx <travis@xxxxxxx>
AuthorDate: Wed, 25 Jan 2017 10:35:19 -0600
Committer: Ingo Molnar <mingo@xxxxxxxxxx>
CommitDate: Wed, 1 Feb 2017 10:20:59 +0100

x86/platform/UV: Add Support for UV4 Hubless NMIs

Merge new UV Hubless NMI support into existing UV NMI handler.

Signed-off-by: Mike Travis <travis@xxxxxxx>
Reviewed-by: Russ Anderson <rja@xxxxxxx>
Acked-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Acked-by: Dimitri Sivanich <sivanich@xxxxxxx>
Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Link: http://lkml.kernel.org/r/20170125163517.585269837@xxxxxxxxxxxxxxxxxxxxxxx
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
---
arch/x86/include/asm/uv/uv_hub.h | 3 +
arch/x86/kernel/apic/x2apic_uv_x.c | 2 +
arch/x86/platform/uv/uv_nmi.c | 193 ++++++++++++++++++++++++++++++++-----
3 files changed, 176 insertions(+), 22 deletions(-)

diff --git a/arch/x86/include/asm/uv/uv_hub.h b/arch/x86/include/asm/uv/uv_hub.h
index 097b80c..72e8300 100644
--- a/arch/x86/include/asm/uv/uv_hub.h
+++ b/arch/x86/include/asm/uv/uv_hub.h
@@ -772,6 +772,7 @@ static inline int uv_num_possible_blades(void)

/* Per Hub NMI support */
extern void uv_nmi_setup(void);
+extern void uv_nmi_setup_hubless(void);

/* BMC sets a bit this MMR non-zero before sending an NMI */
#define UVH_NMI_MMR UVH_SCRATCH5
@@ -799,6 +800,8 @@ struct uv_hub_nmi_s {
atomic_t read_mmr_count; /* count of MMR reads */
atomic_t nmi_count; /* count of true UV NMIs */
unsigned long nmi_value; /* last value read from NMI MMR */
+ bool hub_present; /* false means UV hubless system */
+ bool pch_owner; /* indicates this hub owns PCH */
};

struct uv_cpu_nmi_s {
diff --git a/arch/x86/kernel/apic/x2apic_uv_x.c b/arch/x86/kernel/apic/x2apic_uv_x.c
index d02cc7e..e9f8f8c 100644
--- a/arch/x86/kernel/apic/x2apic_uv_x.c
+++ b/arch/x86/kernel/apic/x2apic_uv_x.c
@@ -1514,6 +1514,8 @@ void __init uv_system_init(void)

if (is_uv_system())
uv_system_init_hub();
+ else
+ uv_nmi_setup_hubless();
}

apic_driver(apic_x2apic_uv_x);
diff --git a/arch/x86/platform/uv/uv_nmi.c b/arch/x86/platform/uv/uv_nmi.c
index 8410e7d..df7b092 100644
--- a/arch/x86/platform/uv/uv_nmi.c
+++ b/arch/x86/platform/uv/uv_nmi.c
@@ -67,6 +67,18 @@ static struct uv_hub_nmi_s **uv_hub_nmi_list;
DEFINE_PER_CPU(struct uv_cpu_nmi_s, uv_cpu_nmi);
EXPORT_PER_CPU_SYMBOL_GPL(uv_cpu_nmi);

+/* UV hubless values */
+#define NMI_CONTROL_PORT 0x70
+#define NMI_DUMMY_PORT 0x71
+#define GPI_NMI_STS_GPP_D_0 0x164
+#define GPI_NMI_ENA_GPP_D_0 0x174
+#define STS_GPP_D_0_MASK 0x1
+#define PAD_CFG_DW0_GPP_D_0 0x4c0
+#define GPIROUTNMI (1ul << 17)
+#define PCH_PCR_GPIO_1_BASE 0xfdae0000ul
+#define PCH_PCR_GPIO_ADDRESS(offset) (int *)((u64)(pch_base) | (u64)(offset))
+
+static u64 *pch_base;
static unsigned long nmi_mmr;
static unsigned long nmi_mmr_clear;
static unsigned long nmi_mmr_pending;
@@ -144,6 +156,19 @@ module_param_named(wait_count, uv_nmi_wait_count, int, 0644);
static int uv_nmi_retry_count = 500;
module_param_named(retry_count, uv_nmi_retry_count, int, 0644);

+static bool uv_pch_intr_enable = true;
+static bool uv_pch_intr_now_enabled;
+module_param_named(pch_intr_enable, uv_pch_intr_enable, bool, 0644);
+
+static int uv_nmi_debug;
+module_param_named(debug, uv_nmi_debug, int, 0644);
+
+#define nmi_debug(fmt, ...) \
+ do { \
+ if (uv_nmi_debug) \
+ pr_info(fmt, ##__VA_ARGS__); \
+ } while (0)
+
/*
* Valid NMI Actions:
* "dump" - dump process stack for each cpu
@@ -192,6 +217,77 @@ static inline void uv_local_mmr_clear_nmi(void)
}

/*
+ * UV hubless NMI handler functions
+ */
+static inline void uv_reassert_nmi(void)
+{
+ /* (from arch/x86/include/asm/mach_traps.h) */
+ outb(0x8f, NMI_CONTROL_PORT);
+ inb(NMI_DUMMY_PORT); /* dummy read */
+ outb(0x0f, NMI_CONTROL_PORT);
+ inb(NMI_DUMMY_PORT); /* dummy read */
+}
+
+static void uv_init_hubless_pch_io(int offset, int mask, int data)
+{
+ int *addr = PCH_PCR_GPIO_ADDRESS(offset);
+ int readd = readl(addr);
+
+ if (mask) { /* OR in new data */
+ int writed = (readd & ~mask) | data;
+
+ nmi_debug("UV:PCH: %p = %x & %x | %x (%x)\n",
+ addr, readd, ~mask, data, writed);
+ writel(writed, addr);
+ } else if (readd & data) { /* clear status bit */
+ nmi_debug("UV:PCH: %p = %x\n", addr, data);
+ writel(data, addr);
+ }
+
+ (void)readl(addr); /* flush write data */
+}
+
+static void uv_nmi_setup_hubless_intr(void)
+{
+ uv_pch_intr_now_enabled = uv_pch_intr_enable;
+
+ uv_init_hubless_pch_io(
+ PAD_CFG_DW0_GPP_D_0, GPIROUTNMI,
+ uv_pch_intr_now_enabled ? GPIROUTNMI : 0);
+
+ nmi_debug("UV:NMI: GPP_D_0 interrupt %s\n",
+ uv_pch_intr_now_enabled ? "enabled" : "disabled");
+}
+
+static int uv_nmi_test_hubless(struct uv_hub_nmi_s *hub_nmi)
+{
+ int *pstat = PCH_PCR_GPIO_ADDRESS(GPI_NMI_STS_GPP_D_0);
+ int status = *pstat;
+
+ hub_nmi->nmi_value = status;
+ atomic_inc(&hub_nmi->read_mmr_count);
+
+ if (!(status & STS_GPP_D_0_MASK)) /* Not a UV external NMI */
+ return 0;
+
+ *pstat = STS_GPP_D_0_MASK; /* Is a UV NMI: clear GPP_D_0 status */
+ (void)*pstat; /* flush write */
+
+ return 1;
+}
+
+static int uv_test_nmi(struct uv_hub_nmi_s *hub_nmi)
+{
+ if (hub_nmi->hub_present)
+ return uv_nmi_test_mmr(hub_nmi);
+
+ if (hub_nmi->pch_owner) /* Only PCH owner can check status */
+ return uv_nmi_test_hubless(hub_nmi);
+
+ return -1;
+}
+
+/*
* If first cpu in on this hub, set hub_nmi "in_nmi" and "owner" values and
* return true. If first cpu in on the system, set global "in_nmi" flag.
*/
@@ -214,6 +310,7 @@ static int uv_check_nmi(struct uv_hub_nmi_s *hub_nmi)
{
int cpu = smp_processor_id();
int nmi = 0;
+ int nmi_detected = 0;

local64_inc(&uv_nmi_count);
this_cpu_inc(uv_cpu_nmi.queries);
@@ -224,20 +321,26 @@ static int uv_check_nmi(struct uv_hub_nmi_s *hub_nmi)
break;

if (raw_spin_trylock(&hub_nmi->nmi_lock)) {
+ nmi_detected = uv_test_nmi(hub_nmi);

- /* check hub MMR NMI flag */
- if (uv_nmi_test_mmr(hub_nmi)) {
+ /* check flag for UV external NMI */
+ if (nmi_detected > 0) {
uv_set_in_nmi(cpu, hub_nmi);
nmi = 1;
break;
}

- /* MMR NMI flag is clear */
+ /* A non-PCH node in a hubless system waits for NMI */
+ else if (nmi_detected < 0)
+ goto slave_wait;
+
+ /* MMR/PCH NMI flag is clear */
raw_spin_unlock(&hub_nmi->nmi_lock);

} else {
- /* wait a moment for the hub nmi locker to set flag */
- cpu_relax();
+
+ /* Wait a moment for the HUB NMI locker to set flag */
+slave_wait: cpu_relax();
udelay(uv_nmi_slave_delay);

/* re-check hub in_nmi flag */
@@ -246,13 +349,20 @@ static int uv_check_nmi(struct uv_hub_nmi_s *hub_nmi)
break;
}

- /* check if this BMC missed setting the MMR NMI flag */
+ /*
+ * Check if this BMC missed setting the MMR NMI flag (or)
+ * UV hubless system where only PCH owner can check flag
+ */
if (!nmi) {
nmi = atomic_read(&uv_in_nmi);
if (nmi)
uv_set_in_nmi(cpu, hub_nmi);
}

+ /* If we're holding the hub lock, release it now */
+ if (nmi_detected < 0)
+ raw_spin_unlock(&hub_nmi->nmi_lock);
+
} while (0);

if (!nmi)
@@ -269,7 +379,10 @@ static inline void uv_clear_nmi(int cpu)
if (cpu == atomic_read(&hub_nmi->cpu_owner)) {
atomic_set(&hub_nmi->cpu_owner, -1);
atomic_set(&hub_nmi->in_nmi, 0);
- uv_local_mmr_clear_nmi();
+ if (hub_nmi->hub_present)
+ uv_local_mmr_clear_nmi();
+ else
+ uv_reassert_nmi();
raw_spin_unlock(&hub_nmi->nmi_lock);
}
}
@@ -297,11 +410,12 @@ static void uv_nmi_cleanup_mask(void)
}
}

-/* Loop waiting as cpus enter nmi handler */
+/* Loop waiting as cpus enter NMI handler */
static int uv_nmi_wait_cpus(int first)
{
int i, j, k, n = num_online_cpus();
int last_k = 0, waiting = 0;
+ int cpu = smp_processor_id();

if (first) {
cpumask_copy(uv_nmi_cpu_mask, cpu_online_mask);
@@ -310,6 +424,12 @@ static int uv_nmi_wait_cpus(int first)
k = n - cpumask_weight(uv_nmi_cpu_mask);
}

+ /* PCH NMI causes only one cpu to respond */
+ if (first && uv_pch_intr_now_enabled) {
+ cpumask_clear_cpu(cpu, uv_nmi_cpu_mask);
+ return n - k - 1;
+ }
+
udelay(uv_nmi_initial_delay);
for (i = 0; i < uv_nmi_retry_count; i++) {
int loop_delay = uv_nmi_loop_delay;
@@ -358,7 +478,7 @@ static void uv_nmi_wait(int master)
break;

/* if not all made it in, send IPI NMI to them */
- pr_alert("UV: Sending NMI IPI to %d non-responding CPUs: %*pbl\n",
+ pr_alert("UV: Sending NMI IPI to %d CPUs: %*pbl\n",
cpumask_weight(uv_nmi_cpu_mask),
cpumask_pr_args(uv_nmi_cpu_mask));

@@ -538,7 +658,7 @@ static inline int uv_nmi_kdb_reason(void)
#else /* !CONFIG_KGDB_KDB */
static inline int uv_nmi_kdb_reason(void)
{
- /* Insure user is expecting to attach gdb remote */
+ /* Ensure user is expecting to attach gdb remote */
if (uv_nmi_action_is("kgdb"))
return 0;

@@ -626,15 +746,18 @@ int uv_handle_nmi(unsigned int reason, struct pt_regs *regs)
/* Pause as all cpus enter the NMI handler */
uv_nmi_wait(master);

- /* Dump state of each cpu */
- if (uv_nmi_action_is("ips") || uv_nmi_action_is("dump"))
+ /* Process actions other than "kdump": */
+ if (uv_nmi_action_is("ips") || uv_nmi_action_is("dump")) {
uv_nmi_dump_state(cpu, regs, master);
-
- /* Call KGDB/KDB if enabled */
- else if (uv_nmi_action_is("kdb") || uv_nmi_action_is("kgdb"))
+ } else if (uv_nmi_action_is("kdb") || uv_nmi_action_is("kgdb")) {
uv_call_kgdb_kdb(cpu, regs, master);
+ } else {
+ if (master)
+ pr_alert("UV: unknown NMI action: %s\n", uv_nmi_action);
+ uv_nmi_sync_exit(master);
+ }

- /* Clear per_cpu "in nmi" flag */
+ /* Clear per_cpu "in_nmi" flag */
this_cpu_write(uv_cpu_nmi.state, UV_NMI_STATE_OUT);

/* Clear MMR NMI flag on each hub */
@@ -648,6 +771,7 @@ int uv_handle_nmi(unsigned int reason, struct pt_regs *regs)
atomic_set(&uv_nmi_cpu, -1);
atomic_set(&uv_in_nmi, 0);
atomic_set(&uv_nmi_kexec_failed, 0);
+ atomic_set(&uv_nmi_slave_continue, SLAVE_CLEAR);
}

uv_nmi_touch_watchdogs();
@@ -697,28 +821,53 @@ void uv_nmi_init(void)
apic_write(APIC_LVT1, value);
}

-void uv_nmi_setup(void)
+/* Setup HUB NMI info */
+void __init uv_nmi_setup_common(bool hubbed)
{
int size = sizeof(void *) * (1 << NODES_SHIFT);
- int cpu, nid;
+ int cpu;

- /* Setup hub nmi info */
- uv_nmi_setup_mmrs();
uv_hub_nmi_list = kzalloc(size, GFP_KERNEL);
- pr_info("UV: NMI hub list @ 0x%p (%d)\n", uv_hub_nmi_list, size);
+ nmi_debug("UV: NMI hub list @ 0x%p (%d)\n", uv_hub_nmi_list, size);
BUG_ON(!uv_hub_nmi_list);
size = sizeof(struct uv_hub_nmi_s);
for_each_present_cpu(cpu) {
- nid = cpu_to_node(cpu);
+ int nid = cpu_to_node(cpu);
if (uv_hub_nmi_list[nid] == NULL) {
uv_hub_nmi_list[nid] = kzalloc_node(size,
GFP_KERNEL, nid);
BUG_ON(!uv_hub_nmi_list[nid]);
raw_spin_lock_init(&(uv_hub_nmi_list[nid]->nmi_lock));
atomic_set(&uv_hub_nmi_list[nid]->cpu_owner, -1);
+ uv_hub_nmi_list[nid]->hub_present = hubbed;
+ uv_hub_nmi_list[nid]->pch_owner = (nid == 0);
}
uv_hub_nmi_per(cpu) = uv_hub_nmi_list[nid];
}
BUG_ON(!alloc_cpumask_var(&uv_nmi_cpu_mask, GFP_KERNEL));
+}
+
+/* Setup for UV Hub systems */
+void __init uv_nmi_setup(void)
+{
+ uv_nmi_setup_mmrs();
+ uv_nmi_setup_common(true);
+ uv_register_nmi_notifier();
+ pr_info("UV: Hub NMI enabled\n");
+}
+
+/* Setup for UV Hubless systems */
+void __init uv_nmi_setup_hubless(void)
+{
+ uv_nmi_setup_common(false);
+ pch_base = xlate_dev_mem_ptr(PCH_PCR_GPIO_1_BASE);
+ nmi_debug("UV: PCH base:%p from 0x%lx, GPP_D_0\n",
+ pch_base, PCH_PCR_GPIO_1_BASE);
+ uv_init_hubless_pch_io(GPI_NMI_ENA_GPP_D_0,
+ STS_GPP_D_0_MASK, STS_GPP_D_0_MASK);
+ uv_nmi_setup_hubless_intr();
+ /* Ensure NMI enabled in Processor Interface Reg: */
+ uv_reassert_nmi();
uv_register_nmi_notifier();
+ pr_info("UV: Hubless NMI enabled\n");
}