[PATCH] AMD Thermal Interrupt Support

Russell Leidich
2007-12-17T18:55:20Z

Hi,

This patch to 2.6.24-rc5 enables AMD Barcelona CPUs to register thermal throttling events as machine checks, in the
same fashion as the analogous Intel code.

Changed files:

arch/x86/kernel/cpu/mcheck/Makefile
arch/x86/kernel/cpu/mcheck/mce_amd_64.c
arch/x86/kernel/cpu/mcheck/mce_intel_64.c
include/asm-x86/mce.h

New files:

arch/x86/kernel/cpu/mcheck/mce_thermal.c

Signed-off-by Russell Leidich <rml@google.com>
--
Russell Leidich

diff -uprN linux-2.6.24-rc5.orig/arch/x86/kernel/cpu/mcheck/Makefile linux-2.6.24-rc5/arch/x86/kernel/cpu/mcheck/Makefile
--- linux-2.6.24-rc5.orig/arch/x86/kernel/cpu/mcheck/Makefile 2007-12-11 14:30:53.533297000 -0800
+++ linux-2.6.24-rc5/arch/x86/kernel/cpu/mcheck/Makefile 2007-12-11 11:56:20.549185000 -0800
@@ -1,4 +1,4 @@
-obj-y = mce_$(BITS).o therm_throt.o
+obj-y = mce_$(BITS).o therm_throt.o mce_thermal.o

obj-$(CONFIG_X86_32) += k7.o p4.o p5.o p6.o winchip.o
obj-$(CONFIG_X86_MCE_INTEL) += mce_intel_64.o
diff -uprN linux-2.6.24-rc5.orig/arch/x86/kernel/cpu/mcheck/mce_amd_64.c linux-2.6.24-rc5/arch/x86/kernel/cpu/mcheck/mce_amd_64.c
--- linux-2.6.24-rc5.orig/arch/x86/kernel/cpu/mcheck/mce_amd_64.c 2007-12-11 14:30:53.559298000 -0800
+++ linux-2.6.24-rc5/arch/x86/kernel/cpu/mcheck/mce_amd_64.c 2007-12-14 17:34:18.749040000 -0800
@@ -20,6 +20,8 @@
#include <linux/interrupt.h>
#include <linux/kobject.h>
#include <linux/notifier.h>
+#include <linux/pci.h>
+#include <linux/pci_ids.h>
#include <linux/sched.h>
#include <linux/smp.h>
#include <linux/sysdev.h>
@@ -29,6 +31,7 @@
#include <asm/msr.h>
#include <asm/percpu.h>
#include <asm/idle.h>
+#include <asm/therm_throt.h>

#define PFX "mce_threshold: "
#define VERSION "version 1.1.1"
@@ -46,6 +49,19 @@
#define MASK_ERR_COUNT_HI 0x00000FFF
#define MASK_BLKPTR_LO 0xFF000000
#define MCG_XBLK_ADDR 0xC0000400
+#define THERM_CTL_F3X64 0x64
+#define PSL_APIC_LO_EN 0x80
+#define PSL_APIC_HI_EN 0x40
+#define HTC_ACTIVE 0x10
+#define HTC_EN 1
+#define NB_PCI_DEV_BASE 0x18
+
+extern int num_k8_northbridges;
+extern struct pci_dev **k8_northbridges;
+
+static int smp_thermal_interrupt_init(void);
+static int thermal_apic_init_allowed;
+static void thermal_apic_init(void *unused);

struct threshold_block {
unsigned int block;
@@ -644,20 +660,31 @@ static void threshold_remove_device(unsi
}

/* get notified when a cpu comes on/off */
-static int threshold_cpu_callback(struct notifier_block *nfb,
+static int amd_cpu_callback(struct notifier_block *nfb,
unsigned long action, void *hcpu)
{
/* cpu was unsigned int to begin with */
unsigned int cpu = (unsigned long)hcpu;

- if (cpu >= NR_CPUS)
- goto out;
-
switch (action) {
case CPU_ONLINE:
case CPU_ONLINE_FROZEN:
threshold_create_device(cpu);
- break;
+ if (thermal_apic_init_allowed) {
+ /*
+ * We need to run thermal_apic_init() on the core that
+ * just came online. If we're already on that core,
+ * then directly run it. Otherwise
+ * smp_call_function_single() to that core.
+ */
+ if (cpu == get_cpu())
+ thermal_apic_init(NULL);
+ else
+ smp_call_function_single(cpu,
+ &thermal_apic_init, NULL, 1, 0);
+ put_cpu();
+ }
+ break;
case CPU_DEAD:
case CPU_DEAD_FROZEN:
threshold_remove_device(cpu);
@@ -665,12 +692,11 @@ static int threshold_cpu_callback(struct
default:
break;
}
- out:
return NOTIFY_OK;
}

-static struct notifier_block threshold_cpu_notifier = {
- .notifier_call = threshold_cpu_callback,
+static struct notifier_block amd_cpu_notifier = {
+ .notifier_call = amd_cpu_callback,
};

static __init int threshold_init_device(void)
@@ -683,8 +709,191 @@ static __init int threshold_init_device(
if (err)
return err;
}
- register_hotcpu_notifier(&threshold_cpu_notifier);
+ register_hotcpu_notifier(&amd_cpu_notifier);
return 0;
}

device_initcall(threshold_init_device);
+
+/*
+ * AMD-specific thermal interrupt handler.
+ */
+void amd_smp_thermal_interrupt(void)
+{
+ unsigned int cpu = smp_processor_id();
+
+ /*
+ * We're here because thermal throttling has just been activated -- not
+ * deactivated -- hence therm_throt_process(1).
+ */
+ if (therm_throt_process(1))
+ mce_log_therm_throt_event(cpu, 1);
+ /*
+ * We'll still get subsequent interrupts even if we don't clear the
+ * status bit in THERM_CTL_F3X64. Take advantage of this fact to avoid
+ * touching PCI space. (If this assumption fails at some point, we'll
+ * need to schedule_work() in order to enter a process context, so that
+ * PCI locks can be asserted for proper access. This requirement, in
+ * turn, creates the need to remember which core interrupted, as the
+ * core which ultimately takes the scheduled work may be different.
+ * With any luck, we'll never need to do this.)
+ */
+}
+
+/*
+ * Initialize each northbridge's thermal throttling logic.
+ */
+static void smp_thermal_northbridge_init(void)
+{
+ int nb_num;
+ u32 therm_ctl_f3x64;
+
+ for (nb_num = 0; nb_num < num_k8_northbridges; nb_num++) {
+ /*
+ * Configure the thermal interrupt for this northbridge.
+ */
+ pci_read_config_dword(k8_northbridges[nb_num],
+ THERM_CTL_F3X64, &therm_ctl_f3x64);
+ therm_ctl_f3x64 |= PSL_APIC_HI_EN | HTC_EN;
+ therm_ctl_f3x64 &= (~PSL_APIC_LO_EN);
+ pci_write_config_dword(k8_northbridges[nb_num],
+ THERM_CTL_F3X64, therm_ctl_f3x64);
+ printk(KERN_INFO "Northbridge at PCI device 0x%x: "
+ "thermal monitoring enabled.\n", NB_PCI_DEV_BASE +
+ nb_num);
+ }
+}
+
+/*
+ * Enable the delivery of thermal interrupts via the local APIC.
+ */
+static void thermal_apic_init(void *unused) {
+ unsigned int apic_lv_therm;
+
+ /* Set up APIC_LVTTHMR to issue THERMAL_APIC_VECTOR. */
+ apic_lv_therm = apic_read(APIC_LVTTHMR);
+ /*
+ * See if some agent other than this routine has already initialized
+ * APIC_LVTTHMR, i.e. if it's unmasked, but not equal to the value that
+ * we would have programmed, had we been here before on this core.
+ */
+ if ((!(apic_lv_therm & APIC_LVT_MASKED)) && ((apic_lv_therm &
+ (APIC_MODE_MASK | APIC_VECTOR_MASK)) != (APIC_DM_FIXED |
+ THERMAL_APIC_VECTOR))) {
+ unsigned int cpu = smp_processor_id();
+
+ printk(KERN_CRIT "CPU 0x%x: Thermal monitoring not "
+ "functional.\n", cpu);
+ if ((apic_lv_therm & APIC_MODE_MASK) == APIC_DM_SMI)
+ printk(KERN_DEBUG "Thermal interrupts already "
+ "handled by SMI according to (((local APIC "
+ "base) + 0x330) bit 0x9).\n");
+ else
+ printk(KERN_DEBUG "Thermal interrupts unexpectedly "
+ "enabled at (((local APIC base) + 0x330) bit "
+ "0x10).\n");
+ } else {
+ /*
+ * Configure the Local Thermal Vector Table Entry to issue
+ * issue thermal interrupts to THERMAL_APIC_VECTOR.
+ *
+ * Start by masking off Delivery Mode and Vector.
+ */
+ apic_lv_therm &= ~(APIC_MODE_MASK | APIC_VECTOR_MASK);
+ /* Fixed interrupt, masked for now. */
+ apic_lv_therm |= APIC_LVT_MASKED | APIC_DM_FIXED |
+ THERMAL_APIC_VECTOR;
+ apic_write(APIC_LVTTHMR, apic_lv_therm);
+ /*
+ * The Intel thermal kernel code implies that there may be a
+ * race involving the mask bit, so clear it only now, after
+ * the other bits have settled.
+ */
+ apic_write(APIC_LVTTHMR, apic_lv_therm & ~APIC_LVT_MASKED);
+ }
+}
+
+/*
+* This function is intended to be called just after thermal throttling has
+ * been enabled. It warns the user if throttling is already active, which
+ * could indicate a failed cooling system. It may be the last chance to get
+ * a warning out before thermal shutdown occurs.
+ */
+static void smp_thermal_early_throttle_check(void)
+{
+ int nb_num;
+ u32 therm_ctl_f3x64;
+
+ for (nb_num = 0; nb_num < num_k8_northbridges; nb_num++) {
+ /*
+ * Read back THERM_CTL_F3X64 to check whther HTC_ACTIVE is
+ * asserted, in which case, warn the user.
+ */
+ pci_read_config_dword(k8_northbridges[nb_num],
+ THERM_CTL_F3X64, &therm_ctl_f3x64);
+ if (therm_ctl_f3x64 & HTC_ACTIVE)
+ printk(KERN_WARNING "High temperature on northbridge "
+ "at PCI device 0x%x. Throttling enabled.\n",
+ NB_PCI_DEV_BASE + nb_num);
+ }
+}
+
+/*
+ * Determine whether or not the northbridges support thermal throttling
+ * interrupts. If so, initialize them for receiving the same, then perform
+ * corresponding APIC initialization on each core.
+ */
+static int smp_thermal_interrupt_init(void)
+{
+ int nb_num;
+ int thermal_registers_functional;
+
+ /*
+ * If there are no recognized northbridges, then we can't talk to the
+ * thermal registers.
+ */
+ thermal_registers_functional = num_k8_northbridges;
+ /*
+ * If any of the northbridges has PCI ID 0x1103, then its thermal
+ * hardware suffers from an erratum which prevents this code from working,
+ * so abort.
+ */
+ for (nb_num = 0; nb_num < num_k8_northbridges; nb_num++) {
+ if ((k8_northbridges[nb_num]->device) == 0x1103) {
+ thermal_registers_functional = 0;
+ break;
+ }
+ }
+ if (thermal_registers_functional) {
+ /*
+ * Assert that we should log thermal throttling events, whenever
+ * we eventually get around to enabling them.
+ */
+ atomic_set(&therm_throt_en, 1);
+ /*
+ * Bind cpu_specific_smp_thermal_interrupt() to
+ * amd_smp_thermal_interrupt().
+ */
+ cpu_specific_smp_thermal_interrupt = amd_smp_thermal_interrupt;
+ smp_thermal_northbridge_init();
+ /*
+ * We've now initialized sufficient fabric to permit the
+ * initialization of the thermal interrupt APIC vectors, such as
+ * when a core comes online and calls amd_cpu_callback().
+ */
+ thermal_apic_init_allowed = 1;
+ /*
+ * Call thermal_apic_init() on each core.
+ */
+ on_each_cpu(&thermal_apic_init, NULL, 1, 0);
+ smp_thermal_early_throttle_check();
+ }
+ return 0;
+}
+
+/*
+ * smp_thermal_interrupt_init cannot execute until PCI has been fully
+ * initialized, hence late_initcall().
+ */
+late_initcall(smp_thermal_interrupt_init);
+
diff -uprN linux-2.6.24-rc5.orig/arch/x86/kernel/cpu/mcheck/mce_intel_64.c linux-2.6.24-rc5/arch/x86/kernel/cpu/mcheck/mce_intel_64.c
--- linux-2.6.24-rc5.orig/arch/x86/kernel/cpu/mcheck/mce_intel_64.c 2007-12-11 14:30:53.564303000 -0800
+++ linux-2.6.24-rc5/arch/x86/kernel/cpu/mcheck/mce_intel_64.c 2007-12-13 12:31:55.311145000 -0800
@@ -13,21 +13,15 @@
#include <asm/idle.h>
#include <asm/therm_throt.h>

-asmlinkage void smp_thermal_interrupt(void)
+void intel_smp_thermal_interrupt(void)
{
__u64 msr_val;

- ack_APIC_irq();
-
- exit_idle();
- irq_enter();
-
rdmsrl(MSR_IA32_THERM_STATUS, msr_val);
if (therm_throt_process(msr_val & 1))
mce_log_therm_throt_event(smp_processor_id(), msr_val);

add_pda(irq_thermal_count, 1);
- irq_exit();
}

static void __cpuinit intel_init_thermal(struct cpuinfo_x86 *c)
@@ -75,6 +69,11 @@ static void __cpuinit intel_init_thermal
wrmsr(MSR_IA32_MISC_ENABLE, l | (1 << 3), h);

l = apic_read(APIC_LVTTHMR);
+ /*
+ * Bind the cpu_specific_smp_thermal_interrupt trampoline to
+ * intel_smp_thermal_interrupt.
+ */
+ cpu_specific_smp_thermal_interrupt = intel_smp_thermal_interrupt;
apic_write(APIC_LVTTHMR, l & ~APIC_LVT_MASKED);
printk(KERN_INFO "CPU%d: Thermal monitoring enabled (%s)\n",
cpu, tm2 ? "TM2" : "TM1");
diff -uprN linux-2.6.24-rc5.orig/arch/x86/kernel/cpu/mcheck/mce_thermal.c linux-2.6.24-rc5/arch/x86/kernel/cpu/mcheck/mce_thermal.c
--- linux-2.6.24-rc5.orig/arch/x86/kernel/cpu/mcheck/mce_thermal.c 1969-12-31 16:00:00.000000000 -0800
+++ linux-2.6.24-rc5/arch/x86/kernel/cpu/mcheck/mce_thermal.c 2007-12-13 12:26:13.057412000 -0800
@@ -0,0 +1,32 @@
+/*
+ * Copyright (c) 2007 Google Inc.
+ *
+ * Written by Mike Waychison <mikew@google.com> and Russell Leidich <rml@google.com>.
+ *
+ * CPU-independent thermal interrupt handler.
+ */
+
+#include <linux/init.h>
+#include <linux/interrupt.h>
+#include "mce.h"
+#include <asm/hw_irq.h>
+#include <asm/idle.h>
+
+static void default_smp_thermal_interrupt(void) {}
+
+cpu_specific_smp_thermal_interrupt_callback cpu_specific_smp_thermal_interrupt =
+ default_smp_thermal_interrupt;
+
+/*
+ * Wrapper for the CPU-specific thermal interrupt service routine. Without
+ * this, we'd have to discern the CPU brand at runtime (because support could
+ * be installed for more than one).
+ */
+asmlinkage void smp_thermal_interrupt(void)
+{
+ ack_APIC_irq();
+ exit_idle();
+ irq_enter();
+ cpu_specific_smp_thermal_interrupt();
+ irq_exit();
+}
diff -uprN linux-2.6.24-rc5.orig/include/asm-x86/mce.h linux-2.6.24-rc5/include/asm-x86/mce.h
--- linux-2.6.24-rc5.orig/include/asm-x86/mce.h 2007-12-11 14:31:34.263515000 -0800
+++ linux-2.6.24-rc5/include/asm-x86/mce.h 2007-12-13 14:10:37.923970000 -0800
@@ -113,7 +113,10 @@ static inline void mce_amd_feature_init(
#endif

void mce_log_therm_throt_event(unsigned int cpu, __u64 status);
+typedef void (*cpu_specific_smp_thermal_interrupt_callback)(void);

+extern cpu_specific_smp_thermal_interrupt_callback
+ cpu_specific_smp_thermal_interrupt;
extern atomic_t mce_entry;

extern void do_machine_check(struct pt_regs *, long);