Merge branch 'merge' of git://git.kernel.org/pub/scm/linux/kernel/git/benh/powerpc

Pull powerpc fixes from Benjamin Herrenschmidt:
 "This is mostly bug fixes (some of them regressions, some of them I
  deemed worth merging now) along with some patches from Li Zhong
  hooking up the new context tracking stuff (for the new full NO_HZ)"

* 'merge' of git://git.kernel.org/pub/scm/linux/kernel/git/benh/powerpc: (25 commits)
  powerpc: Set show_unhandled_signals to 1 by default
  powerpc/perf: Fix setting of "to" addresses for BHRB
  powerpc/pmu: Fix order of interpreting BHRB target entries
  powerpc/perf: Move BHRB code into CONFIG_PPC64 region
  powerpc: select HAVE_CONTEXT_TRACKING for pSeries
  powerpc: Use the new schedule_user API on userspace preemption
  powerpc: Exit user context on notify resume
  powerpc: Exception hooks for context tracking subsystem
  powerpc: Syscall hooks for context tracking subsystem
  powerpc/booke64: Fix kernel hangs at kernel_dbg_exc
  powerpc: Fix irq_set_affinity() return values
  powerpc: Provide __bswapdi2
  powerpc/powernv: Fix starting of secondary CPUs on OPALv2 and v3
  powerpc/powernv: Detect OPAL v3 API version
  powerpc: Fix MAX_STACK_TRACE_ENTRIES too low warning again
  powerpc: Make CONFIG_RTAS_PROC depend on CONFIG_PROC_FS
  powerpc: Bring all threads online prior to migration/hibernation
  powerpc/rtas_flash: Fix validate_flash buffer overflow issue
  powerpc/kexec: Fix kexec when using VMX optimised memcpy
  powerpc: Fix build errors STRICT_MM_TYPECHECKS
  ...

1 files changed, 27 insertions, 14 deletions

diff --git a/arch/powerpc/mm/fault.c b/arch/powerpc/mm/fault.c
index 229951ffc351..8726779e1409 100644
--- a/arch/powerpc/mm/fault.c
+++ b/arch/powerpc/mm/fault.c
@@ -32,6 +32,7 @@
 #include <linux/perf_event.h>
 #include <linux/magic.h>
 #include <linux/ratelimit.h>
+#include <linux/context_tracking.h>
 
 #include <asm/firmware.h>
 #include <asm/page.h>
@@ -196,6 +197,7 @@ static int mm_fault_error(struct pt_regs *regs, unsigned long addr, int fault)
 int __kprobes do_page_fault(struct pt_regs *regs, unsigned long address,
 			    unsigned long error_code)
 {
+	enum ctx_state prev_state = exception_enter();
 	struct vm_area_struct * vma;
 	struct mm_struct *mm = current->mm;
 	unsigned int flags = FAULT_FLAG_ALLOW_RETRY | FAULT_FLAG_KILLABLE;
@@ -204,6 +206,7 @@ int __kprobes do_page_fault(struct pt_regs *regs, unsigned long address,
 	int trap = TRAP(regs);
  	int is_exec = trap == 0x400;
 	int fault;
+	int rc = 0;
 
 #if !(defined(CONFIG_4xx) || defined(CONFIG_BOOKE))
 	/*
@@ -230,28 +233,30 @@ int __kprobes do_page_fault(struct pt_regs *regs, unsigned long address,
 	 * look at it
 	 */
 	if (error_code & ICSWX_DSI_UCT) {
-		int rc = acop_handle_fault(regs, address, error_code);
+		rc = acop_handle_fault(regs, address, error_code);
 		if (rc)
-			return rc;
+			goto bail;
 	}
 #endif /* CONFIG_PPC_ICSWX */
 
 	if (notify_page_fault(regs))
-		return 0;
+		goto bail;
 
 	if (unlikely(debugger_fault_handler(regs)))
-		return 0;
+		goto bail;
 
 	/* On a kernel SLB miss we can only check for a valid exception entry */
-	if (!user_mode(regs) && (address >= TASK_SIZE))
-		return SIGSEGV;
+	if (!user_mode(regs) && (address >= TASK_SIZE)) {
+		rc = SIGSEGV;
+		goto bail;
+	}
 
 #if !(defined(CONFIG_4xx) || defined(CONFIG_BOOKE) || \
 			     defined(CONFIG_PPC_BOOK3S_64))
   	if (error_code & DSISR_DABRMATCH) {
 		/* breakpoint match */
 		do_break(regs, address, error_code);
-		return 0;
+		goto bail;
 	}
 #endif
 
@@ -260,8 +265,10 @@ int __kprobes do_page_fault(struct pt_regs *regs, unsigned long address,
 		local_irq_enable();
 
 	if (in_atomic() || mm == NULL) {
-		if (!user_mode(regs))
-			return SIGSEGV;
+		if (!user_mode(regs)) {
+			rc = SIGSEGV;
+			goto bail;
+		}
 		/* in_atomic() in user mode is really bad,
 		   as is current->mm == NULL. */
 		printk(KERN_EMERG "Page fault in user mode with "
@@ -417,9 +424,11 @@ good_area:
 	 */
 	fault = handle_mm_fault(mm, vma, address, flags);
 	if (unlikely(fault & (VM_FAULT_RETRY|VM_FAULT_ERROR))) {
-		int rc = mm_fault_error(regs, address, fault);
+		rc = mm_fault_error(regs, address, fault);
 		if (rc >= MM_FAULT_RETURN)
-			return rc;
+			goto bail;
+		else
+			rc = 0;
 	}
 
 	/*
@@ -454,7 +463,7 @@ good_area:
 	}
 
 	up_read(&mm->mmap_sem);
-	return 0;
+	goto bail;
 
 bad_area:
 	up_read(&mm->mmap_sem);
@@ -463,7 +472,7 @@ bad_area_nosemaphore:
 	/* User mode accesses cause a SIGSEGV */
 	if (user_mode(regs)) {
 		_exception(SIGSEGV, regs, code, address);
-		return 0;
+		goto bail;
 	}
 
 	if (is_exec && (error_code & DSISR_PROTFAULT))
@@ -471,7 +480,11 @@ bad_area_nosemaphore:
 				   " page (%lx) - exploit attempt? (uid: %d)\n",
 				   address, from_kuid(&init_user_ns, current_uid()));
 
-	return SIGSEGV;
+	rc = SIGSEGV;
+
+bail:
+	exception_exit(prev_state);
+	return rc;
 
 }