Merge branch 'akpm' (patches from Andrew)

Merge even more updates from Andrew Morton:

 - a kernel-wide sweep of show_stack()

 - pagetable cleanups

 - abstract out accesses to mmap_sem - prep for mmap_sem scalability work

 - hch's user acess work

Subsystems affected by this patch series: debug, mm/pagemap, mm/maccess,
mm/documentation.

* emailed patches from Andrew Morton <akpm@linux-foundation.org>: (93 commits)
  include/linux/cache.h: expand documentation over __read_mostly
  maccess: return -ERANGE when probe_kernel_read() fails
  x86: use non-set_fs based maccess routines
  maccess: allow architectures to provide kernel probing directly
  maccess: move user access routines together
  maccess: always use strict semantics for probe_kernel_read
  maccess: remove strncpy_from_unsafe
  tracing/kprobes: handle mixed kernel/userspace probes better
  bpf: rework the compat kernel probe handling
  bpf:bpf_seq_printf(): handle potentially unsafe format string better
  bpf: handle the compat string in bpf_trace_copy_string better
  bpf: factor out a bpf_trace_copy_string helper
  maccess: unify the probe kernel arch hooks
  maccess: remove probe_read_common and probe_write_common
  maccess: rename strnlen_unsafe_user to strnlen_user_nofault
  maccess: rename strncpy_from_unsafe_strict to strncpy_from_kernel_nofault
  maccess: rename strncpy_from_unsafe_user to strncpy_from_user_nofault
  maccess: update the top of file comment
  maccess: clarify kerneldoc comments
  maccess: remove duplicate kerneldoc comments
  ...

3 files changed, 15 insertions, 12 deletions

diff --git a/arch/arc/kernel/process.c b/arch/arc/kernel/process.c
index 315528f04bc1..8c8e5172fecd 100644
--- a/arch/arc/kernel/process.c
+++ b/arch/arc/kernel/process.c
@@ -90,10 +90,10 @@ fault:
 	if (unlikely(ret != -EFAULT))
 		 goto fail;
 
-	down_read(&current->mm->mmap_sem);
+	mmap_read_lock(current->mm);
 	ret = fixup_user_fault(current, current->mm, (unsigned long) uaddr,
 			       FAULT_FLAG_WRITE, NULL);
-	up_read(&current->mm->mmap_sem);
+	mmap_read_unlock(current->mm);
 
 	if (likely(!ret))
 		 goto again;
diff --git a/arch/arc/kernel/stacktrace.c b/arch/arc/kernel/stacktrace.c
index 1e440bbfa876..feba91c9d969 100644
--- a/arch/arc/kernel/stacktrace.c
+++ b/arch/arc/kernel/stacktrace.c
@@ -158,9 +158,11 @@ arc_unwind_core(struct task_struct *tsk, struct pt_regs *regs,
 /* Call-back which plugs into unwinding core to dump the stack in
  * case of panic/OOPs/BUG etc
  */
-static int __print_sym(unsigned int address, void *unused)
+static int __print_sym(unsigned int address, void *arg)
 {
-	printk("  %pS\n", (void *)address);
+	const char *loglvl = arg;
+
+	printk("%s  %pS\n", loglvl, (void *)address);
 	return 0;
 }
 
@@ -217,17 +219,18 @@ static int __get_first_nonsched(unsigned int address, void *unused)
  *-------------------------------------------------------------------------
  */
 
-noinline void show_stacktrace(struct task_struct *tsk, struct pt_regs *regs)
+noinline void show_stacktrace(struct task_struct *tsk, struct pt_regs *regs,
+			      const char *loglvl)
 {
-	pr_info("\nStack Trace:\n");
-	arc_unwind_core(tsk, regs, __print_sym, NULL);
+	printk("%s\nStack Trace:\n", loglvl);
+	arc_unwind_core(tsk, regs, __print_sym, (void *)loglvl);
 }
 EXPORT_SYMBOL(show_stacktrace);
 
 /* Expected by sched Code */
-void show_stack(struct task_struct *tsk, unsigned long *sp)
+void show_stack(struct task_struct *tsk, unsigned long *sp, const char *loglvl)
 {
-	show_stacktrace(tsk, NULL);
+	show_stacktrace(tsk, NULL, loglvl);
 }
 
 /* Another API expected by schedular, shows up in "ps" as Wait Channel
diff --git a/arch/arc/kernel/troubleshoot.c b/arch/arc/kernel/troubleshoot.c
index 3393558876a9..28e8bf04b253 100644
--- a/arch/arc/kernel/troubleshoot.c
+++ b/arch/arc/kernel/troubleshoot.c
@@ -89,7 +89,7 @@ static void show_faulting_vma(unsigned long address)
 	/* can't use print_vma_addr() yet as it doesn't check for
 	 * non-inclusive vma
 	 */
-	down_read(&active_mm->mmap_sem);
+	mmap_read_lock(active_mm);
 	vma = find_vma(active_mm, address);
 
 	/* check against the find_vma( ) behaviour which returns the next VMA
@@ -111,7 +111,7 @@ static void show_faulting_vma(unsigned long address)
 	} else
 		pr_info("    @No matching VMA found\n");
 
-	up_read(&active_mm->mmap_sem);
+	mmap_read_unlock(active_mm);
 }
 
 static void show_ecr_verbose(struct pt_regs *regs)
@@ -240,5 +240,5 @@ void show_kernel_fault_diag(const char *str, struct pt_regs *regs,
 
 	/* Show stack trace if this Fatality happened in kernel mode */
 	if (!user_mode(regs))
-		show_stacktrace(current, regs);
+		show_stacktrace(current, regs, KERN_DEFAULT);
 }