Merge branch 'parisc-4.1-2' of git://git.kernel.org/pub/scm/linux/kernel/git/deller/parisc-linux

Pull parisc fixes from Helge Deller:
 "One important patch which fixes crashes due to stack randomization on
  architectures where the stack grows upwards (currently parisc and
  metag only).

  This bug went unnoticed on parisc since kernel 3.14 where the flexible
  mmap memory layout support was added by commit 9dabf60dc4ab.  The
  changes in fs/exec.c are inside an #ifdef CONFIG_STACK_GROWSUP section
  and will not affect other platforms.

  The other two patches rename args of the kthread_arg() function and
  fixes a printk output"

* 'parisc-4.1-2' of git://git.kernel.org/pub/scm/linux/kernel/git/deller/parisc-linux:
  parisc,metag: Fix crashes due to stack randomization on stack-grows-upwards architectures
  parisc: copy_thread(): rename 'arg' argument to 'kthread_arg'
  parisc: %pf is only for function pointers

3 files changed, 13 insertions, 4 deletions

diff --git a/arch/parisc/include/asm/elf.h b/arch/parisc/include/asm/elf.h
index 3391d061eccc..78c9fd32c554 100644
--- a/arch/parisc/include/asm/elf.h
+++ b/arch/parisc/include/asm/elf.h
@@ -348,6 +348,10 @@ struct pt_regs;	/* forward declaration... */
 
 #define ELF_HWCAP	0
 
+#define STACK_RND_MASK	(is_32bit_task() ? \
+				0x7ff >> (PAGE_SHIFT - 12) : \
+				0x3ffff >> (PAGE_SHIFT - 12))
+
 struct mm_struct;
 extern unsigned long arch_randomize_brk(struct mm_struct *);
 #define arch_randomize_brk arch_randomize_brk
diff --git a/arch/parisc/kernel/process.c b/arch/parisc/kernel/process.c
index 8a488c22a99f..809905a811ed 100644
--- a/arch/parisc/kernel/process.c
+++ b/arch/parisc/kernel/process.c
@@ -181,9 +181,12 @@ int dump_task_fpu (struct task_struct *tsk, elf_fpregset_t *r)
 	return 1;
 }
 
+/*
+ * Copy architecture-specific thread state
+ */
 int
 copy_thread(unsigned long clone_flags, unsigned long usp,
-	    unsigned long arg, struct task_struct *p)
+	    unsigned long kthread_arg, struct task_struct *p)
 {
 	struct pt_regs *cregs = &(p->thread.regs);
 	void *stack = task_stack_page(p);
@@ -195,11 +198,10 @@ copy_thread(unsigned long clone_flags, unsigned long usp,
 	extern void * const child_return;
 
 	if (unlikely(p->flags & PF_KTHREAD)) {
+		/* kernel thread */
 		memset(cregs, 0, sizeof(struct pt_regs));
 		if (!usp) /* idle thread */
 			return 0;
-
-		/* kernel thread */
 		/* Must exit via ret_from_kernel_thread in order
 		 * to call schedule_tail()
 		 */
@@ -215,7 +217,7 @@ copy_thread(unsigned long clone_flags, unsigned long usp,
 #else
 		cregs->gr[26] = usp;
 #endif
-		cregs->gr[25] = arg;
+		cregs->gr[25] = kthread_arg;
 	} else {
 		/* user thread */
 		/* usp must be word aligned.  This also prevents users from
diff --git a/arch/parisc/kernel/sys_parisc.c b/arch/parisc/kernel/sys_parisc.c
index e1ffea2f9a0b..5aba01ac457f 100644
--- a/arch/parisc/kernel/sys_parisc.c
+++ b/arch/parisc/kernel/sys_parisc.c
@@ -77,6 +77,9 @@ static unsigned long mmap_upper_limit(void)
 	if (stack_base > STACK_SIZE_MAX)
 		stack_base = STACK_SIZE_MAX;
 
+	/* Add space for stack randomization. */
+	stack_base += (STACK_RND_MASK << PAGE_SHIFT);
+
 	return PAGE_ALIGN(STACK_TOP - stack_base);
 }