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Subject[PATCH] x86_64: move apic init in init_IRQs (take 2)
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Date

Ok here is the x86_64 version again without moving check_nmi_watchdog.

There is a lot that could be done to move check_nmi_watchdog earlier
or to make it per cpu. Unfortunately when I tried a per cpu
version of check_nmi_watchdog the code failed miserably,
on my dual processor hyperthreaded Xeon. Despite everything being
setup properly. And it isn't reasonable to call check_nmi_watchdog
twice during boot because the second time will take 10 seconds.

All kinds of ugliness exists because we don't initialize
the apics during init_IRQs.
- We calibrate jiffies in non apic mode even when we are using apics.
- We have to have special code to initialize the apics when non-smp.
- The legacy i8259 must exist and be setup correctly, even
we won't use it past initialization.
- The kexec on panic code must restore the state of the io_apics.
- init/main.c needs a special case for !smp smp_init on x86

In addition to code movement I needed a couple of non-obvious changes:
- Move setup_boot_APIC_clock into APIC_late_time_init for
simplicity.
- Use cpu_khz to generate a better approximation of loops_per_jiffies
so I can verify the timer interrupt is working.
- Call setup_apic_nmi_watchdog again after cpu_khz is initialized on
the boot cpu.

Plus APIC is now capitalized properly in kernel informational messages.

Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>


---

arch/x86_64/kernel/apic.c | 72 +++++++++++++++++++++++++++++++++---------
arch/x86_64/kernel/i8259.c | 4 ++
arch/x86_64/kernel/io_apic.c | 6 +++-
arch/x86_64/kernel/smpboot.c | 61 +-----------------------------------
arch/x86_64/kernel/time.c | 6 ++++
include/asm-x86_64/apic.h | 3 +-
include/asm-x86_64/hw_irq.h | 1 +
7 files changed, 76 insertions(+), 77 deletions(-)

635bab0ceddb7f630750dfb48533d0298f02e8bc
diff --git a/arch/x86_64/kernel/apic.c b/arch/x86_64/kernel/apic.c
--- a/arch/x86_64/kernel/apic.c
+++ b/arch/x86_64/kernel/apic.c
@@ -601,6 +601,7 @@ static int __init detect_init_APIC (void

void __init init_apic_mappings(void)
{
+ unsigned int orig_boot_cpu_id;
unsigned long apic_phys;

/*
@@ -621,7 +622,11 @@ void __init init_apic_mappings(void)
* Fetch the APIC ID of the BSP in case we have a
* default configuration (or the MP table is broken).
*/
+ orig_boot_cpu_id = boot_cpu_id;
boot_cpu_id = GET_APIC_ID(apic_read(APIC_ID));
+ if ((orig_boot_cpu_id != -1U) && (orig_boot_cpu_id != boot_cpu_id))
+ printk(KERN_WARNING "Boot APIC ID in local APIC unexpected (%d vs %d)",
+ orig_boot_cpu_id, boot_cpu_id);

#ifdef CONFIG_X86_IO_APIC
{
@@ -759,6 +764,7 @@ static unsigned int calibration_result;

void __init setup_boot_APIC_clock (void)
{
+ unsigned long flags;
if (disable_apic_timer) {
printk(KERN_INFO "Disabling APIC timer\n");
return;
@@ -767,6 +773,7 @@ void __init setup_boot_APIC_clock (void)
printk(KERN_INFO "Using local APIC timer interrupts.\n");
using_apic_timer = 1;

+ local_save_flags(flags);
local_irq_disable();

calibration_result = calibrate_APIC_clock();
@@ -775,7 +782,7 @@ void __init setup_boot_APIC_clock (void)
*/
setup_APIC_timer(calibration_result);

- local_irq_enable();
+ local_irq_restore(flags);
}

void __cpuinit setup_secondary_APIC_clock(void)
@@ -1029,40 +1036,73 @@ asmlinkage void smp_error_interrupt(void

int disable_apic;

+
/*
- * This initializes the IO-APIC and APIC hardware if this is
- * a UP kernel.
+ * This initializes the IO-APIC and APIC hardware.
*/
-int __init APIC_init_uniprocessor (void)
+int __init APIC_init(void)
{
- if (disable_apic) {
- printk(KERN_INFO "Apic disabled\n");
- return -1;
+ if (disable_apic) {
+ printk(KERN_INFO "APIC disabled\n");
+ return -1;
}
- if (!cpu_has_apic) {
+ if (!cpu_has_apic) {
disable_apic = 1;
- printk(KERN_INFO "Apic disabled by BIOS\n");
+ printk(KERN_INFO "APIC disabled by BIOS\n");
return -1;
}

verify_local_APIC();

+ /*
+ * Should not be necessary because the MP table should list the boot
+ * CPU too, but we do it for the sake of robustness anyway.
+ */
+ if (!physid_isset(boot_cpu_id, phys_cpu_present_map)) {
+ printk(KERN_NOTICE "weird, boot CPU (#%d) not listed by the BIOS.\n",
+ boot_cpu_id);
+ physid_set(boot_cpu_id, phys_cpu_present_map);
+ }
+
+ /*
+ * Switch from PIC to APIC mode.
+ */
connect_bsp_APIC();
+ setup_local_APIC();

- phys_cpu_present_map = physid_mask_of_physid(boot_cpu_id);
- apic_write_around(APIC_ID, boot_cpu_id);
+#ifdef CONFIG_X86_IO_APIC
+ /*
+ * Now start the IO-APICs
+ */
+ if (smp_found_config && !skip_ioapic_setup && nr_ioapics)
+ setup_IO_APIC();
+#endif
+ return 0;
+}

- setup_local_APIC();
+void __init APIC_late_time_init(void)
+{
+ /* Improve our loops per jiffy estimate */
+ loops_per_jiffy = ((1000 + HZ - 1)/HZ)*cpu_khz;
+ boot_cpu_data.loops_per_jiffy = loops_per_jiffy;
+ cpu_data[0].loops_per_jiffy = loops_per_jiffy;
+
+ /* setup_apic_nmi_watchdog doesn't work properly before cpu_khz is
+ * initialized. So redo it here to ensure the boot cpu is setup
+ * properly.
+ */
+ if (nmi_watchdog == NMI_LOCAL_APIC)
+ setup_apic_nmi_watchdog();

#ifdef CONFIG_X86_IO_APIC
if (smp_found_config && !skip_ioapic_setup && nr_ioapics)
- setup_IO_APIC();
- else
- nr_ioapics = 0;
+ IO_APIC_late_time_init();
#endif
setup_boot_APIC_clock();
+#ifndef CONFIG_SMP
+ /* SMP kernels perform this check after cpu startup */
check_nmi_watchdog();
- return 0;
+#endif
}

static __init int setup_disableapic(char *str)
diff --git a/arch/x86_64/kernel/i8259.c b/arch/x86_64/kernel/i8259.c
--- a/arch/x86_64/kernel/i8259.c
+++ b/arch/x86_64/kernel/i8259.c
@@ -598,4 +598,8 @@ void __init init_IRQ(void)

if (!acpi_ioapic)
setup_irq(2, &irq2);
+
+#ifdef CONFIG_X86_LOCAL_APIC
+ APIC_init();
+#endif
}
diff --git a/arch/x86_64/kernel/io_apic.c b/arch/x86_64/kernel/io_apic.c
--- a/arch/x86_64/kernel/io_apic.c
+++ b/arch/x86_64/kernel/io_apic.c
@@ -1760,11 +1760,15 @@ void __init setup_IO_APIC(void)
sync_Arb_IDs();
setup_IO_APIC_irqs();
init_IO_APIC_traps();
- check_timer();
if (!acpi_ioapic)
print_IO_APIC();
}

+void __init IO_APIC_late_time_init(void)
+{
+ check_timer();
+}
+
struct sysfs_ioapic_data {
struct sys_device dev;
struct IO_APIC_route_entry entry[0];
diff --git a/arch/x86_64/kernel/smpboot.c b/arch/x86_64/kernel/smpboot.c
--- a/arch/x86_64/kernel/smpboot.c
+++ b/arch/x86_64/kernel/smpboot.c
@@ -871,10 +871,6 @@ static __init void disable_smp(void)
{
cpu_present_map = cpumask_of_cpu(0);
cpu_possible_map = cpumask_of_cpu(0);
- if (smp_found_config)
- phys_cpu_present_map = physid_mask_of_physid(boot_cpu_id);
- else
- phys_cpu_present_map = physid_mask_of_physid(0);
cpu_set(0, cpu_sibling_map[0]);
cpu_set(0, cpu_core_map[0]);
}
@@ -917,40 +913,14 @@ static int __init smp_sanity_check(unsig
*/
if (!smp_found_config) {
printk(KERN_NOTICE "SMP motherboard not detected.\n");
- disable_smp();
- if (APIC_init_uniprocessor())
- printk(KERN_NOTICE "Local APIC not detected."
- " Using dummy APIC emulation.\n");
- return -1;
- }
-
- /*
- * Should not be necessary because the MP table should list the boot
- * CPU too, but we do it for the sake of robustness anyway.
- */
- if (!physid_isset(boot_cpu_id, phys_cpu_present_map)) {
- printk(KERN_NOTICE "weird, boot CPU (#%d) not listed by the BIOS.\n",
- boot_cpu_id);
- physid_set(hard_smp_processor_id(), phys_cpu_present_map);
- }
-
- /*
- * If we couldn't find a local APIC, then get out of here now!
- */
- if (APIC_INTEGRATED(apic_version[boot_cpu_id]) && !cpu_has_apic) {
- printk(KERN_ERR "BIOS bug, local APIC #%d not detected!...\n",
- boot_cpu_id);
- printk(KERN_ERR "... forcing use of dummy APIC emulation. (tell your hw vendor)\n");
- nr_ioapics = 0;
return -1;
}

/*
* If SMP should be disabled, then really disable it!
*/
- if (!max_cpus) {
- printk(KERN_INFO "SMP mode deactivated, forcing use of dummy APIC emulation.\n");
- nr_ioapics = 0;
+ if (!max_cpus || disable_apic) {
+ printk(KERN_INFO "SMP mode deactivated\n");
return -1;
}

@@ -976,33 +946,6 @@ void __init smp_prepare_cpus(unsigned in
disable_smp();
return;
}
-
-
- /*
- * Switch from PIC to APIC mode.
- */
- connect_bsp_APIC();
- setup_local_APIC();
-
- if (GET_APIC_ID(apic_read(APIC_ID)) != boot_cpu_id) {
- panic("Boot APIC ID in local APIC unexpected (%d vs %d)",
- GET_APIC_ID(apic_read(APIC_ID)), boot_cpu_id);
- /* Or can we switch back to PIC here? */
- }
-
- /*
- * Now start the IO-APICs
- */
- if (!skip_ioapic_setup && nr_ioapics)
- setup_IO_APIC();
- else
- nr_ioapics = 0;
-
- /*
- * Set up local APIC timer on boot CPU.
- */
-
- setup_boot_APIC_clock();
}

/*
diff --git a/arch/x86_64/kernel/time.c b/arch/x86_64/kernel/time.c
--- a/arch/x86_64/kernel/time.c
+++ b/arch/x86_64/kernel/time.c
@@ -884,6 +884,7 @@ static struct irqaction irq0 = {

extern void __init config_acpi_tables(void);

+extern void (*late_time_init)(void);
void __init time_init(void)
{
char *timename;
@@ -941,6 +942,11 @@ void __init time_init(void)

set_cyc2ns_scale(cpu_khz / 1000);

+#if CONFIG_X86_LOCAL_APIC
+ if (!disable_apic) {
+ late_time_init = APIC_late_time_init;
+ }
+#endif
#ifndef CONFIG_SMP
time_init_gtod();
#endif
diff --git a/include/asm-x86_64/apic.h b/include/asm-x86_64/apic.h
--- a/include/asm-x86_64/apic.h
+++ b/include/asm-x86_64/apic.h
@@ -94,7 +94,8 @@ extern void release_lapic_nmi(void);
extern void disable_timer_nmi_watchdog(void);
extern void enable_timer_nmi_watchdog(void);
extern void nmi_watchdog_tick (struct pt_regs * regs, unsigned reason);
-extern int APIC_init_uniprocessor (void);
+extern int APIC_init(void);
+extern void APIC_late_time_init(void);
extern void disable_APIC_timer(void);
extern void enable_APIC_timer(void);
extern void clustered_apic_check(void);
diff --git a/include/asm-x86_64/hw_irq.h b/include/asm-x86_64/hw_irq.h
--- a/include/asm-x86_64/hw_irq.h
+++ b/include/asm-x86_64/hw_irq.h
@@ -97,6 +97,7 @@ extern void init_8259A(int aeoi);
extern void FASTCALL(send_IPI_self(int vector));
extern void init_VISWS_APIC_irqs(void);
extern void setup_IO_APIC(void);
+extern void IO_APIC_late_time_init(void);
extern void disable_IO_APIC(void);
extern void print_IO_APIC(void);
extern int IO_APIC_get_PCI_irq_vector(int bus, int slot, int fn);
-
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