powerpc/mm: Add tracking of the number of coprocessors using a context

[mirror_ubuntu-bionic-kernel.git] / arch / powerpc / include / asm / mmu_context.h

diff --git a/arch/powerpc/include/asm/mmu_context.h b/arch/powerpc/include/asm/mmu_context.h
index 6177d43f0ce8afa9c1f6a1101e92ba161e47d97a..4f8a03c74e3f6d2b9c9f4fcb2cb1cfc50f4bd76d 100644 (file)
--- a/arch/powerpc/include/asm/mmu_context.h
+++ b/arch/powerpc/include/asm/mmu_context.h
@@ -92,15 +92,23 @@ static inline void dec_mm_active_cpus(struct mm_struct *mm)
 static inline void mm_context_add_copro(struct mm_struct *mm)
 {
        /*
-        * On hash, should only be called once over the lifetime of
-        * the context, as we can't decrement the active cpus count
-        * and flush properly for the time being.
+        * If any copro is in use, increment the active CPU count
+        * in order to force TLB invalidations to be global as to
+        * propagate to the Nest MMU.
         */
-       inc_mm_active_cpus(mm);
+       if (atomic_inc_return(&mm->context.copros) == 1)
+               inc_mm_active_cpus(mm);
 }
 
 static inline void mm_context_remove_copro(struct mm_struct *mm)
 {
+       int c;
+
+       c = atomic_dec_if_positive(&mm->context.copros);
+
+       /* Detect imbalance between add and remove */
+       WARN_ON(c < 0);
+
        /*
         * Need to broadcast a global flush of the full mm before
         * decrementing active_cpus count, as the next TLBI may be
@@ -111,7 +119,7 @@ static inline void mm_context_remove_copro(struct mm_struct *mm)
         * for the time being. Invalidations will remain global if
         * used on hash.
         */
-       if (radix_enabled()) {
+       if (c == 0 && radix_enabled()) {
                flush_all_mm(mm);
                dec_mm_active_cpus(mm);
        }
@@ -160,9 +168,10 @@ static inline void enter_lazy_tlb(struct mm_struct *mm,
 #endif
 }
 
-static inline void arch_dup_mmap(struct mm_struct *oldmm,
-                                struct mm_struct *mm)
+static inline int arch_dup_mmap(struct mm_struct *oldmm,
+                               struct mm_struct *mm)
 {
+       return 0;
 }
 
 #ifndef CONFIG_PPC_BOOK3S_64