[RFC/PATCH 3/7] ARM: ARM11 MPCore: {clean,flush}_pmd_entry are not preempt safe
Catalin Marinas
catalin.marinas at arm.com
Tue Oct 11 05:53:15 EDT 2011
On Fri, Oct 07, 2011 at 03:38:37AM +0100, gdavis at mvista.com wrote:
> diff --git a/arch/arm/mm/mmu.c b/arch/arm/mm/mmu.c
> index 594d677..3c8253f 100644
> --- a/arch/arm/mm/mmu.c
> +++ b/arch/arm/mm/mmu.c
> @@ -567,12 +567,24 @@ static void __init alloc_init_section(pud_t *pud, unsigned long addr,
> if (addr & SECTION_SIZE)
> pmd++;
>
> + if (cache_ops_need_broadcast())
> + preempt_disable();
> do {
> *pmd = __pmd(phys | type->prot_sect);
> phys += SECTION_SIZE;
> } while (pmd++, addr += SECTION_SIZE, addr != end);
>
> + /* FIXME: Multiple PMD entries may be written above
> + * but only one cache line, up to 8 PMDs depending
> + * on the alignment of this mapping, is flushed below.
> + * IFF this mapping spans >8MiB, then only the first
> + * 8MiB worth of entries will be flushed. Entries
> + * above the 8MiB limit will not be flushed if I
> + * read this correctly.
> + */
> flush_pmd_entry(p);
> + if (cache_ops_need_broadcast())
> + preempt_enable();
My reading of the create_mapping() code is that alloc_init_pud() and
alloc_init_section() are called with a 2MB range only (that's 2
entries) given by pgd_addr_end().
--
Catalin
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