powerpc/mm: Add new hash_page_mm()

This adds a new function hash_page_mm() based on the existing hash_page().
This version allows any struct mm to be passed in, rather than assuming
current. This is useful for servicing co-processor faults which are not in the
context of the current running process.

We need to be careful here as the current hash_page() assumes current in a few
places.

Signed-off-by: Ian Munsie <imunsie@au1.ibm.com>
Signed-off-by: Michael Neuling <mikey@neuling.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

diff --git a/arch/powerpc/include/asm/mmu-hash64.h b/arch/powerpc/include/asm/mmu-hash64.h
index bd813c00ede25bb1113f4bc1908510f233e44532..aeebc94b2bced66d4d5762077629362ece591103 100644 (file)
--- a/arch/powerpc/include/asm/mmu-hash64.h
+++ b/arch/powerpc/include/asm/mmu-hash64.h
@@ -324,6 +324,7 @@ extern int __hash_page_64K(unsigned long ea, unsigned long access,
                           unsigned int local, int ssize);
 struct mm_struct;
 unsigned int hash_page_do_lazy_icache(unsigned int pp, pte_t pte, int trap);
+extern int hash_page_mm(struct mm_struct *mm, unsigned long ea, unsigned long access, unsigned long trap);
 extern int hash_page(unsigned long ea, unsigned long access, unsigned long trap);
 int __hash_page_huge(unsigned long ea, unsigned long access, unsigned long vsid,
                     pte_t *ptep, unsigned long trap, int local, int ssize,

diff --git a/arch/powerpc/mm/hash_utils_64.c b/arch/powerpc/mm/hash_utils_64.c
index fe5609d7a9d74dc2f749453b12d9990db3795d03..d5339a3b99458d191123e56c94a6ef3df0b48fc3 100644 (file)
--- a/arch/powerpc/mm/hash_utils_64.c
+++ b/arch/powerpc/mm/hash_utils_64.c
@@ -904,7 +904,7 @@ void demote_segment_4k(struct mm_struct *mm, unsigned long addr)
                return;
        slice_set_range_psize(mm, addr, 1, MMU_PAGE_4K);
        copro_flush_all_slbs(mm);
-       if (get_paca_psize(addr) != MMU_PAGE_4K) {
+       if ((get_paca_psize(addr) != MMU_PAGE_4K) && (current->mm == mm)) {
                get_paca()->context = mm->context;
                slb_flush_and_rebolt();
        }
@@ -989,12 +989,11 @@ static void check_paca_psize(unsigned long ea, struct mm_struct *mm,
  * -1 - critical hash insertion error
  * -2 - access not permitted by subpage protection mechanism
  */
-int hash_page(unsigned long ea, unsigned long access, unsigned long trap)
+int hash_page_mm(struct mm_struct *mm, unsigned long ea, unsigned long access, unsigned long trap)
 {
        enum ctx_state prev_state = exception_enter();
        pgd_t *pgdir;
        unsigned long vsid;
-       struct mm_struct *mm;
        pte_t *ptep;
        unsigned hugeshift;
        const struct cpumask *tmp;
@@ -1008,7 +1007,6 @@ int hash_page(unsigned long ea, unsigned long access, unsigned long trap)
        switch (REGION_ID(ea)) {
        case USER_REGION_ID:
                user_region = 1;
-               mm = current->mm;
                if (! mm) {
                        DBG_LOW(" user region with no mm !\n");
                        rc = 1;
@@ -1019,7 +1017,6 @@ int hash_page(unsigned long ea, unsigned long access, unsigned long trap)
                vsid = get_vsid(mm->context.id, ea, ssize);
                break;
        case VMALLOC_REGION_ID:
-               mm = &init_mm;
                vsid = get_kernel_vsid(ea, mmu_kernel_ssize);
                if (ea < VMALLOC_END)
                        psize = mmu_vmalloc_psize;
@@ -1104,7 +1101,8 @@ int hash_page(unsigned long ea, unsigned long access, unsigned long trap)
                        WARN_ON(1);
                }
 #endif
-               check_paca_psize(ea, mm, psize, user_region);
+               if (current->mm == mm)
+                       check_paca_psize(ea, mm, psize, user_region);
 
                goto bail;
        }
@@ -1145,7 +1143,8 @@ int hash_page(unsigned long ea, unsigned long access, unsigned long trap)
                }
        }
 
-       check_paca_psize(ea, mm, psize, user_region);
+       if (current->mm == mm)
+               check_paca_psize(ea, mm, psize, user_region);
 #endif /* CONFIG_PPC_64K_PAGES */
 
 #ifdef CONFIG_PPC_HAS_HASH_64K
@@ -1180,6 +1179,17 @@ bail:
        exception_exit(prev_state);
        return rc;
 }
+EXPORT_SYMBOL_GPL(hash_page_mm);
+
+int hash_page(unsigned long ea, unsigned long access, unsigned long trap)
+{
+       struct mm_struct *mm = current->mm;
+
+       if (REGION_ID(ea) == VMALLOC_REGION_ID)
+               mm = &init_mm;
+
+       return hash_page_mm(mm, ea, access, trap);
+}
 EXPORT_SYMBOL_GPL(hash_page);
 
 void hash_preload(struct mm_struct *mm, unsigned long ea,