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[RFC PATCH 2/6] x86/apic: Construct a framework for setuping APIC mode as soon as possible

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  [RFC PATCH 2/6] x86/apic: Construct a framework for setuping APIC mode as soon as possible Dou Liyang <douly.fnst@cn.fujitsu.com> - 2017-03-29 17:00 +0200
    Re: [RFC PATCH 2/6] x86/apic: Construct a framework for setuping  APIC mode as soon as possible Thomas Gleixner <tglx@linutronix.de> - 2017-04-05 13:50 +0200
      Re: [RFC PATCH 2/6] x86/apic: Construct a framework for setuping APIC  mode as soon as possible Dou Liyang <douly.fnst@cn.fujitsu.com> - 2017-04-06 04:30 +0200

#1612004 — [RFC PATCH 2/6] x86/apic: Construct a framework for setuping APIC mode as soon as possible

Now, there are two ways to setup local apic and io-apic in X86 arch:
  1. In an SMP-capable system, it will be done when preparing the
cpus in native_smp_prepare_boot_cpu().
  2. If UP_LATE_INIT is y, it will be done in smp_init()

And, there are many switches in kernel which can determine the way of
APIC mode setup, as shown below:

  1. kconfig :
     CONFIG_X86_64; CONFIG_X86_LOCAL_APIC; CONFIG_x86_IO_APIC
  2. kernel option: disable_apic; skip_ioapic_setup
  3. BIOS : boot_cpu_has(X86_FEATURE_APIC)
  4. MP table: smp_found_config
  5. ACPI: acpi_lapic; acpi_ioapic; nr_ioapic

The setup is late which cause the dump-capture kernel hangs with 'notsc'
option in 1st kernel option. and the use of these switches is messily.

Before make the APIC mode setup earlier, construct a framework first to
prepare for the work and make the logic clear.

Signed-off-by: Dou Liyang <douly.fnst@cn.fujitsu.com>
---
 arch/x86/include/asm/apic.h |  2 ++
 arch/x86/kernel/apic/apic.c | 73 +++++++++++++++++++++++++++++++++++++++++++++
 arch/x86/kernel/irqinit.c   |  3 ++
 3 files changed, 78 insertions(+)

diff --git a/arch/x86/include/asm/apic.h b/arch/x86/include/asm/apic.h
index 20ac73c..c973f18 100644
--- a/arch/x86/include/asm/apic.h
+++ b/arch/x86/include/asm/apic.h
@@ -172,6 +172,8 @@ static inline void disable_local_APIC(void) { }
 # define setup_secondary_APIC_clock x86_init_noop
 static inline void lapic_update_tsc_freq(void) { }
 static inline void apic_virture_wire_mode_setup(void) {}
+static inline void init_bsp_APIC(void) {}
+
 #endif /* !CONFIG_X86_LOCAL_APIC */
 
 #ifdef CONFIG_X86_X2APIC
diff --git a/arch/x86/kernel/apic/apic.c b/arch/x86/kernel/apic/apic.c
index f4fc949..bf4ccd0 100644
--- a/arch/x86/kernel/apic/apic.c
+++ b/arch/x86/kernel/apic/apic.c
@@ -1153,6 +1153,63 @@ void __init sync_Arb_IDs(void)
 			APIC_INT_LEVELTRIG | APIC_DM_INIT);
 }
 
+enum apic_bsp_mode {
+	APIC_BSP_MODEL_PIC = 0,
+	APIC_BSP_MODEL_VIRTUAL_WIRE,
+	APIC_BSP_MODEL_SYMMETRIC_IO,
+	APIC_BSP_MODEL_COUNT
+};
+
+static int __init apic_bsp_mode_check(void)
+{
+
+	/* Check kernel option */
+	if (disable_apic) {
+		pr_info("APIC disabled by kernel option\n");
+		return APIC_BSP_MODEL_PIC;
+	}
+	/* Check BOIS */
+#ifdef CONFIG_X86_64
+	/* On 64-bit, The APIC is integrated, So, must have APIC feature */
+	if (!boot_cpu_has(X86_FEATURE_APIC)) {
+		disable_apic = 1;
+		pr_info("Apic disabled by BIOS\n");
+		return APIC_BSP_MODEL_PIC;
+	}
+#else
+	if (!boot_cpu_has(X86_FEATURE_APIC) &&
+		APIC_INTEGRATED(boot_cpu_apic_version)) {
+		pr_err("BIOS bug, local APIC #%d not detected!...\n",
+			boot_cpu_physical_apicid);
+		pr_err("... forcing use of dummy APIC emulation (tell your hw vendor)\n");
+		return APIC_BSP_MODEL_PIC;
+	}
+#endif
+	/*
+	 * Check MP table, if neither an integrated nor a separate chip
+	 * doesn't exist.
+	 */
+	if (!boot_cpu_has(X86_FEATURE_APIC) && !smp_found_config) {
+		pr_info("BOIS don't support APIC, and no SMP configuration.\n");
+		return APIC_BSP_MODEL_PIC;
+	}
+
+	/* Check MP table, ps: if the virtual wire has been setup */
+	if (!smp_found_config) {
+		disable_ioapic_support();
+
+		/* Check local APIC, if SMP_NO_CONFIG */
+		if (!acpi_lapic)
+			pr_info("SMP motherboard not detected\n");
+
+		return APIC_BSP_MODEL_VIRTUAL_WIRE;
+	}
+
+	/* Other checks of ACPI options will be done in each setup function */
+
+	return APIC_BSP_MODEL_SYMMETRIC_IO;
+}
+
 /*
  * Setup the through-local-APIC virtual wire mode.
  */
@@ -1202,6 +1259,22 @@ void apic_virture_wire_mode_setup(void)
 	apic_write(APIC_LVT1, value);
 }
 
+/* init the interrupt routing model for the BSP */
+void __init init_bsp_APIC(void)
+{
+	switch (apic_bsp_mode_check()) {
+	case APIC_BSP_MODEL_PIC:
+		pr_info("Keep in PIC mode(8259)\n");
+		return;
+	case APIC_BSP_MODEL_VIRTUAL_WIRE:
+		pr_info("switch to virtual wire model.\n");
+		return;
+	case APIC_BSP_MODEL_SYMMETRIC_IO:
+		pr_info("switch to symmectic I/O model.\n");
+		return;
+	}
+}
+
 static void lapic_setup_esr(void)
 {
 	unsigned int oldvalue, value, maxlvt;
diff --git a/arch/x86/kernel/irqinit.c b/arch/x86/kernel/irqinit.c
index b6ef4ea..f30fb16 100644
--- a/arch/x86/kernel/irqinit.c
+++ b/arch/x86/kernel/irqinit.c
@@ -197,4 +197,7 @@ void __init native_init_IRQ(void)
 #ifdef CONFIG_X86_32
 	irq_ctx_init(smp_processor_id());
 #endif
+
+	/* init the IRQ Mode for BSP */
+	init_bsp_APIC();
 }
-- 
2.5.5

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#1616868 — Re: [RFC PATCH 2/6] x86/apic: Construct a framework for setuping APIC mode as soon as possible

On Wed, 29 Mar 2017, Dou Liyang wrote:

> Now, there are two ways to setup local apic and io-apic in X86 arch:
>   1. In an SMP-capable system, it will be done when preparing the
> cpus in native_smp_prepare_boot_cpu().
>   2. If UP_LATE_INIT is y, it will be done in smp_init()
> 
> And, there are many switches in kernel which can determine the way of
> APIC mode setup, as shown below:
> 
>   1. kconfig :
>      CONFIG_X86_64; CONFIG_X86_LOCAL_APIC; CONFIG_x86_IO_APIC
>   2. kernel option: disable_apic; skip_ioapic_setup
>   3. BIOS : boot_cpu_has(X86_FEATURE_APIC)
>   4. MP table: smp_found_config
>   5. ACPI: acpi_lapic; acpi_ioapic; nr_ioapic
> 
> The setup is late which cause the dump-capture kernel hangs with 'notsc'
> option in 1st kernel option. and the use of these switches is messily.
> 
> Before make the APIC mode setup earlier, construct a framework first to
> prepare for the work and make the logic clear.

Calling that a framework is slightly exaggerated. It's a selector function
for the interrupt delivery mode.

>  #ifdef CONFIG_X86_X2APIC
> diff --git a/arch/x86/kernel/apic/apic.c b/arch/x86/kernel/apic/apic.c
> index f4fc949..bf4ccd0 100644
> --- a/arch/x86/kernel/apic/apic.c
> +++ b/arch/x86/kernel/apic/apic.c
> @@ -1153,6 +1153,63 @@ void __init sync_Arb_IDs(void)
>  			APIC_INT_LEVELTRIG | APIC_DM_INIT);
>  }
>  
> +enum apic_bsp_mode {
> +	APIC_BSP_MODEL_PIC = 0,
> +	APIC_BSP_MODEL_VIRTUAL_WIRE,
> +	APIC_BSP_MODEL_SYMMETRIC_IO,
> +	APIC_BSP_MODEL_COUNT
> +};
> +
> +static int __init apic_bsp_mode_check(void)
> +{
> +
> +	/* Check kernel option */
> +	if (disable_apic) {
> +		pr_info("APIC disabled by kernel option\n");

kernel option is ambiguous. "APIC disabled via kernel command line" is telling
clearly where this comes from.

> +		return APIC_BSP_MODEL_PIC;
> +	}
> +	/* Check BOIS */
> +#ifdef CONFIG_X86_64
> +	/* On 64-bit, The APIC is integrated, So, must have APIC feature */
> +	if (!boot_cpu_has(X86_FEATURE_APIC)) {
> +		disable_apic = 1;
> +		pr_info("Apic disabled by BIOS\n");

Please use APIC consistently. 

> +		return APIC_BSP_MODEL_PIC;
> +	}
> +#else
> +	if (!boot_cpu_has(X86_FEATURE_APIC) &&
> +		APIC_INTEGRATED(boot_cpu_apic_version)) {
> +		pr_err("BIOS bug, local APIC #%d not detected!...\n",
> +			boot_cpu_physical_apicid);

Please make that

		pr_err(FW_BUG, "Local APIC %d not detected, force emulation",
		       boot_cpu_physical_apicid);

and for consistency reasosns this should also set disable_apic to 1.

> +		return APIC_BSP_MODEL_PIC;
> +	}
> +#endif
> +	/*
> +	 * Check MP table, if neither an integrated nor a separate chip
> +	 * doesn't exist.
> +	 */
> +	if (!boot_cpu_has(X86_FEATURE_APIC) && !smp_found_config) {
> +		pr_info("BOIS don't support APIC, and no SMP configuration.\n");

s/BOIS/BIOS/

and for consistency reasosns this should also set disable_apic to 1.


> +		return APIC_BSP_MODEL_PIC;
> +	}
> +
> +	/* Check MP table, ps: if the virtual wire has been setup */
> +	if (!smp_found_config) {
> +		disable_ioapic_support();
> +
> +		/* Check local APIC, if SMP_NO_CONFIG */
> +		if (!acpi_lapic)
> +			pr_info("SMP motherboard not detected\n");
> +
> +		return APIC_BSP_MODEL_VIRTUAL_WIRE;
> +	}
> +
> +	/* Other checks of ACPI options will be done in each setup function */
> +
> +	return APIC_BSP_MODEL_SYMMETRIC_IO;
> +}
> +
>  /*
>   * Setup the through-local-APIC virtual wire mode.
>   */
> @@ -1202,6 +1259,22 @@ void apic_virture_wire_mode_setup(void)
>  	apic_write(APIC_LVT1, value);
>  }
>  
> +/* init the interrupt routing model for the BSP */
> +void __init init_bsp_APIC(void)
> +{
> +	switch (apic_bsp_mode_check()) {
> +	case APIC_BSP_MODEL_PIC:
> +		pr_info("Keep in PIC mode(8259)\n");
> +		return;
> +	case APIC_BSP_MODEL_VIRTUAL_WIRE:
> +		pr_info("switch to virtual wire model.\n");

Please consistenly start sentences with upper case letters.

Thanks,

	tglx

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#1617470 — Re: [RFC PATCH 2/6] x86/apic: Construct a framework for setuping APIC mode as soon as possible

Hi Thomas,

At 04/05/2017 07:46 PM, Thomas Gleixner wrote:
> On Wed, 29 Mar 2017, Dou Liyang wrote:
>
>> Now, there are two ways to setup local apic and io-apic in X86 arch:
>>   1. In an SMP-capable system, it will be done when preparing the
>> cpus in native_smp_prepare_boot_cpu().
>>   2. If UP_LATE_INIT is y, it will be done in smp_init()
>>
>> And, there are many switches in kernel which can determine the way of
>> APIC mode setup, as shown below:
>>
>>   1. kconfig :
>>      CONFIG_X86_64; CONFIG_X86_LOCAL_APIC; CONFIG_x86_IO_APIC
>>   2. kernel option: disable_apic; skip_ioapic_setup
>>   3. BIOS : boot_cpu_has(X86_FEATURE_APIC)
>>   4. MP table: smp_found_config
>>   5. ACPI: acpi_lapic; acpi_ioapic; nr_ioapic
>>
>> The setup is late which cause the dump-capture kernel hangs with 'notsc'
>> option in 1st kernel option. and the use of these switches is messily.
>>
>> Before make the APIC mode setup earlier, construct a framework first to
>> prepare for the work and make the logic clear.
>
> Calling that a framework is slightly exaggerated. It's a selector function
> for the interrupt delivery mode.
>

Yes, Selector is what I want.

To tell the truth, I've been looking for a word that can summarize this
patch for a long time. :)


>>  #ifdef CONFIG_X86_X2APIC
>> diff --git a/arch/x86/kernel/apic/apic.c b/arch/x86/kernel/apic/apic.c
>> index f4fc949..bf4ccd0 100644
>> --- a/arch/x86/kernel/apic/apic.c
>> +++ b/arch/x86/kernel/apic/apic.c
>> @@ -1153,6 +1153,63 @@ void __init sync_Arb_IDs(void)
>>  			APIC_INT_LEVELTRIG | APIC_DM_INIT);
>>  }
>>
>> +enum apic_bsp_mode {
>> +	APIC_BSP_MODEL_PIC = 0,
>> +	APIC_BSP_MODEL_VIRTUAL_WIRE,
>> +	APIC_BSP_MODEL_SYMMETRIC_IO,
>> +	APIC_BSP_MODEL_COUNT
>> +};
>> +
>> +static int __init apic_bsp_mode_check(void)
>> +{
>> +
>> +	/* Check kernel option */
>> +	if (disable_apic) {
>> +		pr_info("APIC disabled by kernel option\n");
>
> kernel option is ambiguous. "APIC disabled via kernel command line" is telling
> clearly where this comes from.
>

Thanks, will modify in my next version.

>> +		return APIC_BSP_MODEL_PIC;
>> +	}
>> +	/* Check BOIS */
>> +#ifdef CONFIG_X86_64
>> +	/* On 64-bit, The APIC is integrated, So, must have APIC feature */
>> +	if (!boot_cpu_has(X86_FEATURE_APIC)) {
>> +		disable_apic = 1;
>> +		pr_info("Apic disabled by BIOS\n");
>
> Please use APIC consistently.

Oops, Yes.

>
>> +		return APIC_BSP_MODEL_PIC;
>> +	}
>> +#else
>> +	if (!boot_cpu_has(X86_FEATURE_APIC) &&
>> +		APIC_INTEGRATED(boot_cpu_apic_version)) {
>> +		pr_err("BIOS bug, local APIC #%d not detected!...\n",
>> +			boot_cpu_physical_apicid);
>
> Please make that
>
> 		pr_err(FW_BUG, "Local APIC %d not detected, force emulation",
> 		       boot_cpu_physical_apicid);
>
> and for consistency reasosns this should also set disable_apic to 1.
>
>> +		return APIC_BSP_MODEL_PIC;

Yes. I will.

>> +	}
>> +#endif
>> +	/*
>> +	 * Check MP table, if neither an integrated nor a separate chip
>> +	 * doesn't exist.
>> +	 */
>> +	if (!boot_cpu_has(X86_FEATURE_APIC) && !smp_found_config) {
>> +		pr_info("BOIS don't support APIC, and no SMP configuration.\n");
>
> s/BOIS/BIOS/
>
> and for consistency reasosns this should also set disable_apic to 1.
>

OK.

>
>> +		return APIC_BSP_MODEL_PIC;
>> +	}
>> +
>> +	/* Check MP table, ps: if the virtual wire has been setup */
>> +	if (!smp_found_config) {
>> +		disable_ioapic_support();
>> +
>> +		/* Check local APIC, if SMP_NO_CONFIG */
>> +		if (!acpi_lapic)
>> +			pr_info("SMP motherboard not detected\n");
>> +
>> +		return APIC_BSP_MODEL_VIRTUAL_WIRE;
>> +	}
>> +
>> +	/* Other checks of ACPI options will be done in each setup function */
>> +
>> +	return APIC_BSP_MODEL_SYMMETRIC_IO;
>> +}
>> +
>>  /*
>>   * Setup the through-local-APIC virtual wire mode.
>>   */
>> @@ -1202,6 +1259,22 @@ void apic_virture_wire_mode_setup(void)
>>  	apic_write(APIC_LVT1, value);
>>  }
>>
>> +/* init the interrupt routing model for the BSP */
>> +void __init init_bsp_APIC(void)
>> +{
>> +	switch (apic_bsp_mode_check()) {
>> +	case APIC_BSP_MODEL_PIC:
>> +		pr_info("Keep in PIC mode(8259)\n");
>> +		return;
>> +	case APIC_BSP_MODEL_VIRTUAL_WIRE:
>> +		pr_info("switch to virtual wire model.\n");
>
> Please consistently start sentences with upper case letters.

Yes, I will check all the sentences and comments again carefully.

Thanks,
	Liyang
>
> Thanks,
>
> 	tglx
>
>
>

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