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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] [PATCH] arm: Use HTPIDR to point to per-CPU state
On Thu, 2012-03-29 at 15:20 +0100, Tim Deegan wrote:
> # HG changeset patch
> # User Tim Deegan <tim@xxxxxxx>
> # Date 1333030787 -3600
> # Node ID dad4fc193c4b160ac55df0354d4deb925c0c18b2
> # Parent bf12b6236d32cc69e6ffd0f21a178849a263fa2e
> arm: Use HTPIDR to point to per-CPU state.
>
> Rather than having the per-VCPU stack contain a pointer to the
> per-PCPU state, use the CPU's hypervisor thread ID register for that.
>
> Signed-off-by: Tim Deegan <tim@xxxxxxx>
>
> diff -r bf12b6236d32 -r dad4fc193c4b xen/arch/arm/setup.c
> --- a/xen/arch/arm/setup.c Thu Mar 29 12:08:41 2012 +0100
> +++ b/xen/arch/arm/setup.c Thu Mar 29 15:19:47 2012 +0100
> @@ -167,7 +167,7 @@ void __init start_xen(unsigned long boot
>
> percpu_init_areas();
> set_processor_id(0); /* needed early, for smp_processor_id() */
> - __set_current((struct vcpu *)0xfffff000); /* debug sanity */
> + set_current((struct vcpu *)0xfffff000); /* debug sanity */
> idle_vcpu[0] = current;
>
> smp_prepare_cpus(cpus);
> diff -r bf12b6236d32 -r dad4fc193c4b xen/arch/arm/smpboot.c
> --- a/xen/arch/arm/smpboot.c Thu Mar 29 12:08:41 2012 +0100
> +++ b/xen/arch/arm/smpboot.c Thu Mar 29 15:19:47 2012 +0100
> @@ -49,6 +49,9 @@ static bool_t cpu_is_dead = 0;
> /* Number of non-boot CPUs ready to enter C */
> unsigned long __initdata ready_cpus = 0;
>
> +/* ID of the PCPU we're running on */
> +DEFINE_PER_CPU(unsigned int, cpu_id);
> +
> void __init
> smp_prepare_cpus (unsigned int max_cpus)
> {
> @@ -102,8 +105,6 @@ void __cpuinit start_secondary(unsigned
> /* Setup Hyp vector base */
> WRITE_CP32((uint32_t) hyp_traps_vector, HVBAR);
>
> - dprintk(XENLOG_DEBUG, "CPU %li awake.\n", cpuid);
> -
> mmu_init_secondary_cpu();
> gic_init_secondary_cpu();
>
> @@ -120,7 +121,7 @@ void __cpuinit start_secondary(unsigned
>
> local_irq_enable();
>
> - dprintk(XENLOG_DEBUG, "CPU %li booted.\n", cpuid);
> + dprintk(XENLOG_DEBUG, "CPU %u booted.\n", smp_processor_id());
>
> startup_cpu_idle_loop();
> }
> diff -r bf12b6236d32 -r dad4fc193c4b xen/include/asm-arm/cpregs.h
> --- a/xen/include/asm-arm/cpregs.h Thu Mar 29 12:08:41 2012 +0100
> +++ b/xen/include/asm-arm/cpregs.h Thu Mar 29 15:19:47 2012 +0100
> @@ -198,6 +198,7 @@
> /* CP15 CR13: */
> #define FCSEIDR p15,0,c13,c0,0 /* FCSE Process ID Register */
> #define CONTEXTIDR p15,0,c13,c0,1 /* Context ID Register */
> +#define HTPIDR p15,4,c13,c0,2 /* Hyp. Software Thread ID Register
> */
>
> /* CP15 CR14: */
> #define CNTPCT p15,0,c14 /* Time counter value */
> diff -r bf12b6236d32 -r dad4fc193c4b xen/include/asm-arm/current.h
> --- a/xen/include/asm-arm/current.h Thu Mar 29 12:08:41 2012 +0100
> +++ b/xen/include/asm-arm/current.h Thu Mar 29 15:19:47 2012 +0100
> @@ -11,17 +11,16 @@
>
> struct vcpu;
>
> -/*
> - * Which VCPU is "current" on this PCPU.
> - */
> +/* Which VCPU is "current" on this PCPU. */
> DECLARE_PER_CPU(struct vcpu *, curr_vcpu);
>
> +#define current (this_cpu(curr_vcpu))
> +#define set_current(vcpu) do { current = (vcpu); } while (0)
> +
> +/* Per-VCPU state that lives at the top of the stack */
> struct cpu_info {
> struct cpu_user_regs guest_cpu_user_regs;
> unsigned long elr;
> - /* The following are valid iff this VCPU is current */
> - unsigned int processor_id;
> - unsigned long per_cpu_offset;
> unsigned int pad;
> };
>
> @@ -31,22 +30,6 @@ static inline struct cpu_info *get_cpu_i
> return (struct cpu_info *)((sp & ~(STACK_SIZE - 1)) + STACK_SIZE -
> sizeof(struct cpu_info));
> }
>
> -#define get_processor_id() (get_cpu_info()->processor_id)
> -#define set_processor_id(id) do { \
> - struct cpu_info *ci__ = get_cpu_info(); \
> - ci__->per_cpu_offset = __per_cpu_offset[ci__->processor_id = (id)]; \
> -} while (0)
> -
> -#define get_current() (this_cpu(curr_vcpu))
> -#define __set_current(vcpu) (this_cpu(curr_vcpu) = (vcpu))
> -#define set_current(vcpu) do { \
> - int cpu = get_processor_id(); \
> - vcpu->arch.cpu_info->processor_id = cpu; \
> - vcpu->arch.cpu_info->per_cpu_offset = __per_cpu_offset[cpu]; \
> - __set_current(vcpu); \
> -} while (0)
> -#define current (get_current())
> -
> #define guest_cpu_user_regs() (&get_cpu_info()->guest_cpu_user_regs)
>
> #define switch_stack_and_jump(stack, fn) \
> diff -r bf12b6236d32 -r dad4fc193c4b xen/include/asm-arm/percpu.h
> --- a/xen/include/asm-arm/percpu.h Thu Mar 29 12:08:41 2012 +0100
> +++ b/xen/include/asm-arm/percpu.h Thu Mar 29 15:19:47 2012 +0100
> @@ -5,7 +5,6 @@
> extern char __per_cpu_start[], __per_cpu_data_end[];
> extern unsigned long __per_cpu_offset[NR_CPUS];
> void percpu_init_areas(void);
> -#endif
>
> /* Separate out the type, so (int[3], foo) works. */
> #define __DEFINE_PER_CPU(type, name, suffix) \
> @@ -16,10 +15,18 @@ void percpu_init_areas(void);
> #define per_cpu(var, cpu) \
> (*RELOC_HIDE(&per_cpu__##var, __per_cpu_offset[cpu]))
> #define __get_cpu_var(var) \
> - (*RELOC_HIDE(&per_cpu__##var, get_cpu_info()->per_cpu_offset))
> + (*RELOC_HIDE(&per_cpu__##var, READ_CP32(HTPIDR)))
>
> #define DECLARE_PER_CPU(type, name) extern __typeof__(type) per_cpu__##name
>
> +DECLARE_PER_CPU(unsigned int, cpu_id);
> +#define get_processor_id() (this_cpu(cpu_id))
> +#define set_processor_id(id) do { \
> + WRITE_CP32(__per_cpu_offset[cpuid], HTPIDR); \
> + this_cpu(cpu_id) = (id); \
This macro uses id, cpu_id and cpuid all at the same time...
The one I'm not really sure about is cpuid, where did he come from?
Looks like it might be a local variable in the two places which call
set_processor_id, and also happens to be the id argument in one of those
cases (the other using literal 0).
> +} while(0)
> +#endif
> +
> #endif /* __ARM_PERCPU_H__ */
> /*
> * Local variables:
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