powerpc: Remove unused paca->pgdir field

The pgdir field in the paca was a leftover from the dynamic VSIDs
patch, and is not used in the current kernel code.  This removes it.
Signed-off-by: Paul Mackerras <paulus@samba.org>

arch/powerpc/kernel/asm-offsets.c

@@ -122,9 +122,6 @@ int main(void)
 	DEFINE(PACASLBCACHE, offsetof(struct paca_struct, slb_cache));
 	DEFINE(PACASLBCACHEPTR, offsetof(struct paca_struct, slb_cache_ptr));
 	DEFINE(PACACONTEXTID, offsetof(struct paca_struct, context.id));
-#ifdef CONFIG_PPC_64K_PAGES
-	DEFINE(PACAPGDIR, offsetof(struct paca_struct, pgdir));
-#endif
 #ifdef CONFIG_HUGETLB_PAGE
 	DEFINE(PACALOWHTLBAREAS, offsetof(struct paca_struct, context.low_htlb_areas));
 	DEFINE(PACAHIGHHTLBAREAS, offsetof(struct paca_struct, context.high_htlb_areas));

arch/powerpc/mm/slb.c

@@ -122,9 +122,6 @@ void switch_slb(struct task_struct *tsk, struct mm_struct *mm)
 
 	get_paca()->slb_cache_ptr = 0;
 	get_paca()->context = mm->context;
-#ifdef CONFIG_PPC_64K_PAGES
-	get_paca()->pgdir = mm->pgd;
-#endif /* CONFIG_PPC_64K_PAGES */
 
 	/*
 	 * preload some userspace segments into the SLB.

arch/powerpc/mm/stab.c

@@ -200,10 +200,6 @@ void switch_stab(struct task_struct *tsk, struct mm_struct *mm)
 
 	__get_cpu_var(stab_cache_ptr) = 0;
 
-#ifdef CONFIG_PPC_64K_PAGES
-	get_paca()->pgdir = mm->pgd;
-#endif /* CONFIG_PPC_64K_PAGES */
-
 	/* Now preload some entries for the new task */
 	if (test_tsk_thread_flag(tsk, TIF_32BIT))
 		unmapped_base = TASK_UNMAPPED_BASE_USER32;

include/asm-powerpc/mmu_context.h

@@ -20,16 +20,9 @@
  * 2 of the License, or (at your option) any later version.
  */
 
-/*
- * Getting into a kernel thread, there is no valid user segment, mark
- * paca->pgdir NULL so that SLB miss on user addresses will fault
- */
 static inline void enter_lazy_tlb(struct mm_struct *mm,
 				  struct task_struct *tsk)
 {
-#ifdef CONFIG_PPC_64K_PAGES
-	get_paca()->pgdir = NULL;
-#endif /* CONFIG_PPC_64K_PAGES */
 }
 
 #define NO_CONTEXT	0
@@ -52,13 +45,8 @@ static inline void switch_mm(struct mm_struct *prev, struct mm_struct *next,
 		cpu_set(smp_processor_id(), next->cpu_vm_mask);
 
 	/* No need to flush userspace segments if the mm doesnt change */
-#ifdef CONFIG_PPC_64K_PAGES
-	if (prev == next && get_paca()->pgdir == next->pgd)
-		return;
-#else
 	if (prev == next)
 		return;
-#endif /* CONFIG_PPC_64K_PAGES */
 
 #ifdef CONFIG_ALTIVEC
 	if (cpu_has_feature(CPU_FTR_ALTIVEC))

include/asm-powerpc/paca.h

@@ -79,9 +79,6 @@ struct paca_struct {
 	u64 exmc[10];		/* used for machine checks */
 	u64 exslb[10];		/* used for SLB/segment table misses
  				 * on the linear mapping */
-#ifdef CONFIG_PPC_64K_PAGES
-	pgd_t *pgdir;
-#endif /* CONFIG_PPC_64K_PAGES */
 
 	mm_context_t context;
 	u16 slb_cache[SLB_CACHE_ENTRIES];