1 files changed, 17 insertions, 92 deletions

diff --git a/arch/powerpc/mm/book3s64/slb.c b/arch/powerpc/mm/book3s64/slb.c
index 6b783552403c..15f73abd1506 100644
--- a/arch/powerpc/mm/book3s64/slb.c
+++ b/arch/powerpc/mm/book3s64/slb.c
@@ -42,6 +42,15 @@ early_param("stress_slb", parse_stress_slb);
 
 __ro_after_init DEFINE_STATIC_KEY_FALSE(stress_slb_key);
 
+bool no_slb_preload __initdata;
+static int __init parse_no_slb_preload(char *p)
+{
+	no_slb_preload = true;
+	return 0;
+}
+early_param("no_slb_preload", parse_no_slb_preload);
+__ro_after_init DEFINE_STATIC_KEY_FALSE(no_slb_preload_key);
+
 static void assert_slb_presence(bool present, unsigned long ea)
 {
 #ifdef CONFIG_DEBUG_VM
@@ -294,11 +303,14 @@ static bool preload_hit(struct thread_info *ti, unsigned long esid)
 	return false;
 }
 
-static bool preload_add(struct thread_info *ti, unsigned long ea)
+static void preload_add(struct thread_info *ti, unsigned long ea)
 {
 	unsigned char idx;
 	unsigned long esid;
 
+	if (slb_preload_disabled())
+		return;
+
 	if (mmu_has_feature(MMU_FTR_1T_SEGMENT)) {
 		/* EAs are stored >> 28 so 256MB segments don't need clearing */
 		if (ea & ESID_MASK_1T)
@@ -308,7 +320,7 @@ static bool preload_add(struct thread_info *ti, unsigned long ea)
 	esid = ea >> SID_SHIFT;
 
 	if (preload_hit(ti, esid))
-		return false;
+		return;
 
 	idx = (ti->slb_preload_tail + ti->slb_preload_nr) % SLB_PRELOAD_NR;
 	ti->slb_preload_esid[idx] = esid;
@@ -316,8 +328,6 @@ static bool preload_add(struct thread_info *ti, unsigned long ea)
 		ti->slb_preload_tail = (ti->slb_preload_tail + 1) % SLB_PRELOAD_NR;
 	else
 		ti->slb_preload_nr++;
-
-	return true;
 }
 
 static void preload_age(struct thread_info *ti)
@@ -328,94 +338,6 @@ static void preload_age(struct thread_info *ti)
 	ti->slb_preload_tail = (ti->slb_preload_tail + 1) % SLB_PRELOAD_NR;
 }
 
-void slb_setup_new_exec(void)
-{
-	struct thread_info *ti = current_thread_info();
-	struct mm_struct *mm = current->mm;
-	unsigned long exec = 0x10000000;
-
-	WARN_ON(irqs_disabled());
-
-	/*
-	 * preload cache can only be used to determine whether a SLB
-	 * entry exists if it does not start to overflow.
-	 */
-	if (ti->slb_preload_nr + 2 > SLB_PRELOAD_NR)
-		return;
-
-	hard_irq_disable();
-
-	/*
-	 * We have no good place to clear the slb preload cache on exec,
-	 * flush_thread is about the earliest arch hook but that happens
-	 * after we switch to the mm and have already preloaded the SLBEs.
-	 *
-	 * For the most part that's probably okay to use entries from the
-	 * previous exec, they will age out if unused. It may turn out to
-	 * be an advantage to clear the cache before switching to it,
-	 * however.
-	 */
-
-	/*
-	 * preload some userspace segments into the SLB.
-	 * Almost all 32 and 64bit PowerPC executables are linked at
-	 * 0x10000000 so it makes sense to preload this segment.
-	 */
-	if (!is_kernel_addr(exec)) {
-		if (preload_add(ti, exec))
-			slb_allocate_user(mm, exec);
-	}
-
-	/* Libraries and mmaps. */
-	if (!is_kernel_addr(mm->mmap_base)) {
-		if (preload_add(ti, mm->mmap_base))
-			slb_allocate_user(mm, mm->mmap_base);
-	}
-
-	/* see switch_slb */
-	asm volatile("isync" : : : "memory");
-
-	local_irq_enable();
-}
-
-void preload_new_slb_context(unsigned long start, unsigned long sp)
-{
-	struct thread_info *ti = current_thread_info();
-	struct mm_struct *mm = current->mm;
-	unsigned long heap = mm->start_brk;
-
-	WARN_ON(irqs_disabled());
-
-	/* see above */
-	if (ti->slb_preload_nr + 3 > SLB_PRELOAD_NR)
-		return;
-
-	hard_irq_disable();
-
-	/* Userspace entry address. */
-	if (!is_kernel_addr(start)) {
-		if (preload_add(ti, start))
-			slb_allocate_user(mm, start);
-	}
-
-	/* Top of stack, grows down. */
-	if (!is_kernel_addr(sp)) {
-		if (preload_add(ti, sp))
-			slb_allocate_user(mm, sp);
-	}
-
-	/* Bottom of heap, grows up. */
-	if (heap && !is_kernel_addr(heap)) {
-		if (preload_add(ti, heap))
-			slb_allocate_user(mm, heap);
-	}
-
-	/* see switch_slb */
-	asm volatile("isync" : : : "memory");
-
-	local_irq_enable();
-}
-
 static void slb_cache_slbie_kernel(unsigned int index)
 {
 	unsigned long slbie_data = get_paca()->slb_cache[index];
@@ -502,6 +424,9 @@ void switch_slb(struct task_struct *tsk, struct mm_struct *mm)
 
 	copy_mm_to_paca(mm);
 
+	if (slb_preload_disabled())
+		return;
+
 	/*
 	 * We gradually age out SLBs after a number of context switches to
 	 * reduce reload overhead of unused entries (like we do with FP/VEC