Re: [Xen-devel] [PATCH v4 1/7] xen/arm: introduce early_ioremap

[Ian Campbell <Ian.Campbell@xxxxxxxxxx>]

On Tue, 2013-01-08 at 20:03 +0000, Stefano Stabellini wrote:
> Introduce a function to map a range of physical memory into Xen virtual
> memory.
> It doesn't need domheap to be setup.
> It is going to be used to map the videoram.
> 
> Add flush_xen_data_tlb_range_va, that flushes a range of virtual addresses.
> Replace all the calls to flush_xen_data_tlb_va with calls to
> flush_xen_data_tlb_range_va and remove flush_xen_data_tlb_va.
> 
> In the case of the dest_va tlb flush at the beginning of
> setup_pagetables, flush the entire 2MB mapping rather than just the
> first 4K.
> 
> 
> Changes in v4:
> - rename flush_xen_data_tlb_range to flush_xen_data_tlb_range_va;
> - replace all the calls to flush_xen_data_tlb_va, with calls to
> flush_xen_data_tlb_range_va;
> - flush the entire 2MB mapping at BOOT_MISC_VIRT_START rather than just
> the first 4k;
> - remove flush_xen_data_tlb_va;

These all seem like a separate patch (or patches) to me.

> - fix indentation;
> - rename EARLY_VMAP_START/END to EARLY_VMAP_VIRT_START/END;
> - mark early_ioremap as __init;
> - reduce the amount of casts in early_ioremap.

[...]
>  /*
> - * Flush one VA's hypervisor mappings from the data TLB. This is not
> + * Flush a range of VA's hypervisor mappings from the data TLB. This is not
>   * sufficient when changing code mappings or for self modifying code.
>   */
> -static inline void flush_xen_data_tlb_va(unsigned long va)
> +static inline void flush_xen_data_tlb_range_va(unsigned long va, unsigned 
> long size)
>  {
> -    asm volatile("dsb;" /* Ensure preceding are visible */
> -                 STORE_CP32(0, TLBIMVAH)
> -                 "dsb;" /* Ensure completion of the TLB flush */
> -                 "isb;"
> -                 : : "r" (va) : "memory");
> +    unsigned long end = va + size;
> +    while ( va < end ) {
> +        asm volatile("dsb;" /* Ensure preceding are visible */
> +                     STORE_CP32(0, TLBIMVAH)
> +                     "dsb;" /* Ensure completion of the TLB flush */
> +                     "isb;"

You can hoist all the barriers here to above/below the loop I think.

Ian.


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