On Thu, Dec 08, 2016 at 07:19:51PM +1100, Alexey Kardashevskiy wrote:
> This makes mm_iommu_lookup() able to work in realmode by replacing
> list_for_each_entry_rcu() (which can do debug stuff which can fail in
> real mode) with list_for_each_entry_lockless().
>
> This adds realmode version of mm_iommu_ua_to_hpa() which adds
> explicit vmalloc'd-to-linear address conversion.
> Unlike mm_iommu_ua_to_hpa(), mm_iommu_ua_to_hpa_rm() can fail.
>
> This changes mm_iommu_preregistered() to receive @mm as in real mode
> @current does not always have a correct pointer.
>
> This adds realmode version of mm_iommu_lookup() which receives @mm
> (for the same reason as for mm_iommu_preregistered()) and uses
> lockless version of list_for_each_entry_rcu().
>
> Signed-off-by: Alexey Kardashevskiy <aik@xxxxxxxxx>
Reviewed-by: David Gibson <david@xxxxxxxxxxxxxxxxxxxxx>
> ---
> arch/powerpc/include/asm/mmu_context.h | 4 ++++
> arch/powerpc/mm/mmu_context_iommu.c | 39 ++++++++++++++++++++++++++++++++++
> 2 files changed, 43 insertions(+)
>
> diff --git a/arch/powerpc/include/asm/mmu_context.h b/arch/powerpc/include/asm/mmu_context.h
> index b9e3f0aca261..c70c8272523d 100644
> --- a/arch/powerpc/include/asm/mmu_context.h
> +++ b/arch/powerpc/include/asm/mmu_context.h
> @@ -29,10 +29,14 @@ extern void mm_iommu_init(struct mm_struct *mm);
> extern void mm_iommu_cleanup(struct mm_struct *mm);
> extern struct mm_iommu_table_group_mem_t *mm_iommu_lookup(struct mm_struct *mm,
> unsigned long ua, unsigned long size);
> +extern struct mm_iommu_table_group_mem_t *mm_iommu_lookup_rm(
> + struct mm_struct *mm, unsigned long ua, unsigned long size);
> extern struct mm_iommu_table_group_mem_t *mm_iommu_find(struct mm_struct *mm,
> unsigned long ua, unsigned long entries);
> extern long mm_iommu_ua_to_hpa(struct mm_iommu_table_group_mem_t *mem,
> unsigned long ua, unsigned long *hpa);
> +extern long mm_iommu_ua_to_hpa_rm(struct mm_iommu_table_group_mem_t *mem,
> + unsigned long ua, unsigned long *hpa);
> extern long mm_iommu_mapped_inc(struct mm_iommu_table_group_mem_t *mem);
> extern void mm_iommu_mapped_dec(struct mm_iommu_table_group_mem_t *mem);
> #endif
> diff --git a/arch/powerpc/mm/mmu_context_iommu.c b/arch/powerpc/mm/mmu_context_iommu.c
> index 104bad029ce9..631d32f5937b 100644
> --- a/arch/powerpc/mm/mmu_context_iommu.c
> +++ b/arch/powerpc/mm/mmu_context_iommu.c
> @@ -314,6 +314,25 @@ struct mm_iommu_table_group_mem_t *mm_iommu_lookup(struct mm_struct *mm,
> }
> EXPORT_SYMBOL_GPL(mm_iommu_lookup);
>
> +struct mm_iommu_table_group_mem_t *mm_iommu_lookup_rm(struct mm_struct *mm,
> + unsigned long ua, unsigned long size)
> +{
> + struct mm_iommu_table_group_mem_t *mem, *ret = NULL;
> +
> + list_for_each_entry_lockless(mem, &mm->context.iommu_group_mem_list,
> + next) {
> + if ((mem->ua <= ua) &&
> + (ua + size <= mem->ua +
> + (mem->entries << PAGE_SHIFT))) {
> + ret = mem;
> + break;
> + }
> + }
> +
> + return ret;
> +}
> +EXPORT_SYMBOL_GPL(mm_iommu_lookup_rm);
> +
> struct mm_iommu_table_group_mem_t *mm_iommu_find(struct mm_struct *mm,
> unsigned long ua, unsigned long entries)
> {
> @@ -345,6 +364,26 @@ long mm_iommu_ua_to_hpa(struct mm_iommu_table_group_mem_t *mem,
> }
> EXPORT_SYMBOL_GPL(mm_iommu_ua_to_hpa);
>
> +long mm_iommu_ua_to_hpa_rm(struct mm_iommu_table_group_mem_t *mem,
> + unsigned long ua, unsigned long *hpa)
> +{
> + const long entry = (ua - mem->ua) >> PAGE_SHIFT;
> + void *va = &mem->hpas[entry];
> + unsigned long *pa;
> +
> + if (entry >= mem->entries)
> + return -EFAULT;
> +
> + pa = (void *) vmalloc_to_phys(va);
> + if (!pa)
> + return -EFAULT;
> +
> + *hpa = *pa | (ua & ~PAGE_MASK);
> +
> + return 0;
> +}
> +EXPORT_SYMBOL_GPL(mm_iommu_ua_to_hpa_rm);
> +
> long mm_iommu_mapped_inc(struct mm_iommu_table_group_mem_t *mem)
> {
> if (atomic64_inc_not_zero(&mem->mapped))
--
David Gibson | I'll have my music baroque, and my code
david AT gibson.dropbear.id.au | minimalist, thank you. NOT _the_ _other_
| _way_ _around_!
http://www.ozlabs.org/~dgibson
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