Re: [PATCH for review] [133/145] x86_64: Support physical cpu hotplug for x86_64

[Len Brown]

On Thursday 10 August 2006 15:37, Andi Kleen wrote:
> r
> 
> From: Ashok Raj <ashok.raj@xxxxxxxxx>
> 
> This patch enables ACPI based physical CPU hotplug support for x86_64. 
> Implements acpi_map_lsapic() and acpi_unmap_lsapic() to support physical cpu
> hotplug.

> Signed-off-by: Ashok Raj <ashok.raj@xxxxxxxxx>
> Signed-off-by: Andi Kleen <ak@xxxxxxx>
> Cc: Andi Kleen <ak@xxxxxx>
> Cc: "Brown, Len" <len.brown@xxxxxxxxx>
> Signed-off-by: Andrew Morton <akpm@xxxxxxxx>
> ---
> 
>  arch/i386/kernel/acpi/boot.c |   69 ++++++++++++++++++++++++++++++++++++++++---
>  arch/i386/kernel/mpparse.c   |    2 -
>  include/asm-i386/smp.h       |    1 
>  3 files changed, 67 insertions(+), 5 deletions(-)
> 
> Index: linux/arch/i386/kernel/acpi/boot.c
> ===================================================================
> --- linux.orig/arch/i386/kernel/acpi/boot.c
> +++ linux/arch/i386/kernel/acpi/boot.c
> @@ -26,6 +26,7 @@
>  #include <linux/init.h>
>  #include <linux/acpi.h>
>  #include <linux/efi.h>
> +#include <linux/cpumask.h>
>  #include <linux/module.h>
>  #include <linux/dmi.h>
>  #include <linux/irq.h>
> @@ -512,16 +513,76 @@ EXPORT_SYMBOL(acpi_register_gsi);
>  #ifdef CONFIG_ACPI_HOTPLUG_CPU
>  int acpi_map_lsapic(acpi_handle handle, int *pcpu)
>  {
> -	/* TBD */
> -	return -EINVAL;
> +	struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
> +	union acpi_object *obj;
> +	struct acpi_table_lapic *lapic;

Lets _not_ have a routine called acpi_map_lsapic() that on ia64 maps an lsapic
and on i386 and x86_64 maps a lapic.

If you can't share the same routine between 3 architectures, then at least give
it a generic name that applies to both lsapic and lapic.

thanks,
-Len


> +	cpumask_t tmp_map, new_map;
> +	u8 physid;
> +	int cpu;
> +
> +	if (ACPI_FAILURE(acpi_evaluate_object(handle, "_MAT", NULL, &buffer)))
> +		return -EINVAL;
> +
> +	if (!buffer.length || !buffer.pointer)
> +		return -EINVAL;
> +
> +	obj = buffer.pointer;
> +	if (obj->type != ACPI_TYPE_BUFFER ||
> +	    obj->buffer.length < sizeof(*lapic)) {
> +		kfree(buffer.pointer);
> +		return -EINVAL;
> +	}
> +
> +	lapic = (struct acpi_table_lapic *)obj->buffer.pointer;
> +
> +	if ((lapic->header.type != ACPI_MADT_LAPIC) ||
> +	    (!lapic->flags.enabled)) {
> +		kfree(buffer.pointer);
> +		return -EINVAL;
> +	}
> +
> +	physid = lapic->id;
> +
> +	kfree(buffer.pointer);
> +	buffer.length = ACPI_ALLOCATE_BUFFER;
> +	buffer.pointer = NULL;
> +
> +	tmp_map = cpu_present_map;
> +	mp_register_lapic(physid, lapic->flags.enabled);
> +
> +	/*
> +	 * If mp_register_lapic successfully generates a new logical cpu
> +	 * number, then the following will get us exactly what was mapped
> +	 */
> +	cpus_andnot(new_map, cpu_present_map, tmp_map);
> +	if (cpus_empty(new_map)) {
> +		printk ("Unable to map lapic to logical cpu number\n");
> +		return -EINVAL;
> +	}
> +
> +	cpu = first_cpu(new_map);
> +
> +	*pcpu = cpu;
> +	return 0;
>  }
>  
>  EXPORT_SYMBOL(acpi_map_lsapic);
>  
>  int acpi_unmap_lsapic(int cpu)
>  {
> -	/* TBD */
> -	return -EINVAL;
> +	int i;
> +
> +	for_each_possible_cpu(i) {
> +		if (x86_acpiid_to_apicid[i] == x86_cpu_to_apicid[cpu]) {
> +			x86_acpiid_to_apicid[i] = -1;
> +			break;
> +		}
> +	}
> +	x86_cpu_to_apicid[cpu] = -1;
> +	cpu_clear(cpu, cpu_present_map);
> +	num_processors--;
> +
> +	return (0);
>  }
>  
>  EXPORT_SYMBOL(acpi_unmap_lsapic);
> Index: linux/arch/i386/kernel/mpparse.c
> ===================================================================
> --- linux.orig/arch/i386/kernel/mpparse.c
> +++ linux/arch/i386/kernel/mpparse.c
> @@ -69,7 +69,7 @@ unsigned int def_to_bigsmp = 0;
>  /* Processor that is doing the boot up */
>  unsigned int boot_cpu_physical_apicid = -1U;
>  /* Internal processor count */
> -static unsigned int __devinitdata num_processors;
> +unsigned int __cpuinitdata num_processors;
>  
>  /* Bitmask of physically existing CPUs */
>  physid_mask_t phys_cpu_present_map;
> Index: linux/include/asm-i386/smp.h
> ===================================================================
> --- linux.orig/include/asm-i386/smp.h
> +++ linux/include/asm-i386/smp.h
> @@ -84,6 +84,7 @@ static inline int hard_smp_processor_id(
>  
>  extern int __cpu_disable(void);
>  extern void __cpu_die(unsigned int cpu);
> +extern unsigned int num_processors;
>  
>  #endif /* !__ASSEMBLY__ */
>  
> -
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