1 files changed, 23 insertions, 4 deletions

diff --git a/arch/powerpc/kernel/process.c b/arch/powerpc/kernel/process.c
index 0a3216433051..c930ac38e59f 100644
--- a/arch/powerpc/kernel/process.c
+++ b/arch/powerpc/kernel/process.c
@@ -1016,9 +1016,13 @@ void show_stack(struct task_struct *tsk, unsigned long *stack)
 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
         int curr_frame = current->curr_ret_stack;
         extern void return_to_handler(void);
-        unsigned long addr = (unsigned long)return_to_handler;
+        unsigned long rth = (unsigned long)return_to_handler;
+        unsigned long mrth = -1;
 #ifdef CONFIG_PPC64
-        addr = *(unsigned long*)addr;
+        extern void mod_return_to_handler(void);
+        rth = *(unsigned long *)rth;
+        mrth = (unsigned long)mod_return_to_handler;
+        mrth = *(unsigned long *)mrth;
 #endif
 #endif
 
@@ -1044,7 +1048,7 @@ void show_stack(struct task_struct *tsk, unsigned long *stack)
                 if (!firstframe || ip != lr) {
                         printk("["REG"] ["REG"] %pS", sp, ip, (void *)ip);
 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
-                        if (ip == addr && curr_frame >= 0) {
+                        if ((ip == rth || ip == mrth) && curr_frame >= 0) {
                                 printk(" (%pS)",
                                        (void *)current->ret_stack[curr_frame].ret);
                                 curr_frame--;
@@ -1165,7 +1169,22 @@ 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_PPC_STD_MMU_64
+        /*
+         * 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;