Merge branch 'tracing/urgent' into tracing/core

Merge reason: Pick up latest fixes and update to latest upstream.

Signed-off-by: Ingo Molnar <mingo@elte.hu>

1 files changed, 16 insertions, 1 deletions

diff --git a/arch/powerpc/kernel/process.c b/arch/powerpc/kernel/process.c
index 0a3216433051..1168c5f440ab 100644
--- a/arch/powerpc/kernel/process.c
+++ b/arch/powerpc/kernel/process.c
@@ -1165,7 +1165,22 @@ static inline unsigned long brk_rnd(void)
 
 unsigned long arch_randomize_brk(struct mm_struct *mm)
 {
-	unsigned long ret = PAGE_ALIGN(mm->brk + brk_rnd());
+	unsigned long base = mm->brk;
+	unsigned long ret;
+
+#ifdef CONFIG_PPC64
+	/*
+	 * If we are using 1TB segments and we are allowed to randomise
+	 * the heap, we can put it above 1TB so it is backed by a 1TB
+	 * segment. Otherwise the heap will be in the bottom 1TB
+	 * which always uses 256MB segments and this may result in a
+	 * performance penalty.
+	 */
+	if (!is_32bit_task() && (mmu_highuser_ssize == MMU_SEGSIZE_1T))
+		base = max_t(unsigned long, mm->brk, 1UL << SID_SHIFT_1T);
+#endif
+
+	ret = PAGE_ALIGN(base + brk_rnd());
 
 	if (ret < mm->brk)
 		return mm->brk;