Re: [Xen-devel] [PATCH v5 07/12] x86/apic: Unify interrupt mode setup for UP system

[Dou Liyang]

Hi Thomas,

At 07/03/2017 02:19 AM, Thomas Gleixner wrote:

On Fri, 30 Jun 2017, Dou Liyang wrote:

 static inline int apic_force_enable(unsigned long addr)
diff --git a/arch/x86/kernel/apic/apic.c b/arch/x86/kernel/apic/apic.c
index 0601054..9bf7e95 100644
--- a/arch/x86/kernel/apic/apic.c
+++ b/arch/x86/kernel/apic/apic.c
@@ -1198,6 +1198,10 @@ static int __init apic_intr_mode_select(int *upmode)
}
 #endif

+#ifdef CONFIG_UP_LATE_INIT
+   *upmode = true;
+#endif


This is really wrong. The upmode decision, which is required for calling
apic_bsp_setup() should not happen here, really. As I told you in the
previous patch, use the return code and then you can make further decisions
in apic_intr_mode_init().


Really thanks for your detail explaining, I learned more than i read
from books about the programming skill.



And you do it there w/o any ifdeffery:

static void apic_intr_mode_init(void)
{
bool upmode = IS_ENABLED(CONFIG_UP_LATE_INIT);

switch () {
case :
upmode = true;

}
apic_bsp_setup(upmode);
}


This looks more beautiful than mine.  I will use it in the next version.

Thanks,

dou.



Thanks,

tglx







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Re: [Xen-devel] [PATCH v5 07/12] x86/apic: Unify interrupt mode setup for UP system

[Thomas Gleixner]

On Fri, 30 Jun 2017, Dou Liyang wrote:
>  static inline int apic_force_enable(unsigned long addr)
> diff --git a/arch/x86/kernel/apic/apic.c b/arch/x86/kernel/apic/apic.c
> index 0601054..9bf7e95 100644
> --- a/arch/x86/kernel/apic/apic.c
> +++ b/arch/x86/kernel/apic/apic.c
> @@ -1198,6 +1198,10 @@ static int __init apic_intr_mode_select(int *upmode)
>   }
>  #endif
>  
> +#ifdef CONFIG_UP_LATE_INIT
> + *upmode = true;
> +#endif

This is really wrong. The upmode decision, which is required for calling
apic_bsp_setup() should not happen here, really. As I told you in the
previous patch, use the return code and then you can make further decisions
in apic_intr_mode_init().

And you do it there w/o any ifdeffery:

static void apic_intr_mode_init(void)
{
bool upmode = IS_ENABLED(CONFIG_UP_LATE_INIT);

switch () {
case :
upmode = true;

}
apic_bsp_setup(upmode);
}

Thanks,

tglx

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[Xen-devel] [PATCH v5 07/12] x86/apic: Unify interrupt mode setup for UP system

[Dou Liyang]

In UniProcessor kernel with UP_LATE_INIT=y, it enables and setups
interrupt delivery mode in up_late_init().

Unify it to apic_intr_mode_init(), remove APIC_init_uniprocessor().

Signed-off-by: Dou Liyang 
---
 arch/x86/include/asm/apic.h |  1 -
 arch/x86/kernel/apic/apic.c | 49 +
 2 files changed, 9 insertions(+), 41 deletions(-)

diff --git a/arch/x86/include/asm/apic.h b/arch/x86/include/asm/apic.h
index bfbf715..b35bbbf 100644
--- a/arch/x86/include/asm/apic.h
+++ b/arch/x86/include/asm/apic.h
@@ -144,7 +144,6 @@ void register_lapic_address(unsigned long address);
 extern void setup_boot_APIC_clock(void);
 extern void setup_secondary_APIC_clock(void);
 extern void lapic_update_tsc_freq(void);
-extern int APIC_init_uniprocessor(void);
 
 #ifdef CONFIG_X86_64
 static inline int apic_force_enable(unsigned long addr)
diff --git a/arch/x86/kernel/apic/apic.c b/arch/x86/kernel/apic/apic.c
index 0601054..9bf7e95 100644
--- a/arch/x86/kernel/apic/apic.c
+++ b/arch/x86/kernel/apic/apic.c
@@ -1198,6 +1198,10 @@ static int __init apic_intr_mode_select(int *upmode)
}
 #endif
 
+#ifdef CONFIG_UP_LATE_INIT
+   *upmode = true;
+#endif
+
/* Check MP table or ACPI MADT configuration */
if (!smp_found_config) {
disable_ioapic_support();
@@ -2380,51 +2384,16 @@ void __init apic_bsp_setup(bool upmode)
setup_IO_APIC();
 }
 
-/*
- * This initializes the IO-APIC and APIC hardware if this is
- * a UP kernel.
- */
-int __init APIC_init_uniprocessor(void)
+#ifdef CONFIG_UP_LATE_INIT
+void __init up_late_init(void)
 {
-   if (disable_apic) {
-   pr_info("Apic disabled\n");
-   return -1;
-   }
-#ifdef CONFIG_X86_64
-   if (!boot_cpu_has(X86_FEATURE_APIC)) {
-   disable_apic = 1;
-   pr_info("Apic disabled by BIOS\n");
-   return -1;
-   }
-#else
-   if (!smp_found_config && !boot_cpu_has(X86_FEATURE_APIC))
-   return -1;
-
-   /*
-* Complain if the BIOS pretends there is one.
-*/
-   if (!boot_cpu_has(X86_FEATURE_APIC) &&
-   APIC_INTEGRATED(boot_cpu_apic_version)) {
-   pr_err("BIOS bug, local APIC 0x%x not detected!...\n",
-   boot_cpu_physical_apicid);
-   return -1;
-   }
-#endif
+   apic_intr_mode_init();
 
-   if (!smp_found_config)
-   disable_ioapic_support();
+   if (apic_intr_mode == APIC_PIC)
+   return;
 
-   default_setup_apic_routing();
-   apic_bsp_setup(true);
/* Setup local timer */
x86_init.timers.setup_percpu_clockev();
-   return 0;
-}
-
-#ifdef CONFIG_UP_LATE_INIT
-void __init up_late_init(void)
-{
-   APIC_init_uniprocessor();
 }
 #endif
 
-- 
2.5.5




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