powerpc/mmu: Add real mode support for IOMMU preregistered memory

BugLink: http://bugs.launchpad.net/bugs/1686019
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@ozlabs.ru>
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
(cherry picked from commit 6b5c19c55266f6efd10ffac0e9f9f2b7aa420a58)
Signed-off-by: Jose Ricardo Ziviani <joserz@linux.vnet.ibm.com>
Acked-by: Stefan Bader <stefan.bader@canonical.com>
Acked-by: Kleber Sacilotto de Souza <kleber.souza@canonical.com>
Signed-off-by: Kleber Sacilotto de Souza <kleber.souza@canonical.com>

diff --git a/arch/powerpc/include/asm/mmu_context.h b/arch/powerpc/include/asm/mmu_context.h
index b9e3f0aca261da2233a086cb41150bc3afacb9dc..c70c8272523d0ec3d76381c9f2d66275e4f33c25 100644 (file)
--- 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 7de7124ac91bf939ef26aa9f25d5bd8f88d0f57e..8ca097ad1c713cc5749d954e478a51b3fe9746e3 100644 (file)
--- 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))