Merge branch 'upstream' of git://git.linux-mips.org/pub/scm/ralf/upstream-linus

Pull MIPS fixes from Ralf Baechle:
 "Another round of MIPS fixes for 4.2.  No area does particularly stand
  out but we have a two unpleasant ones:

   - Kernel ptes are marked with a global bit which allows the kernel to
     share kernel TLB entries between all processes.  For this to work
     both entries of an adjacent even/odd pte pair need to have the
     global bit set.  There has been a subtle race in setting the other
     entry's global bit since ~ 2000 but it take particularly
     pathological workloads that essentially do mostly vmalloc/vfree to
     trigger this.

     This pull request fixes the 64-bit case but leaves the case of 32
     bit CPUs with 64 bit ptes unsolved for now.  The unfixed cases
     affect hardware that is not available in the field yet.

   - Instruction emulation requires loading instructions from user space
     but the current fast but simplistic approach will fail on pages
     that are PROT_EXEC but !PROT_READ.  For this reason we temporarily
     do not permit this permission and will map pages with PROT_EXEC |
     PROT_READ.

  The remainder of this pull request is more or less across the field
  and the short log explains them well"

* 'upstream' of git://git.linux-mips.org/pub/scm/ralf/upstream-linus:
  MIPS: Make set_pte() SMP safe.
  MIPS: Replace add and sub instructions in relocate_kernel.S with addiu
  MIPS: Flush RPS on kernel entry with EVA
  Revert "MIPS: BCM63xx: Provide a plat_post_dma_flush hook"
  MIPS: BMIPS: Delete unused Kconfig symbol
  MIPS: Export get_c0_perfcount_int()
  MIPS: show_stack: Fix stack trace with EVA
  MIPS: do_mcheck: Fix kernel code dump with EVA
  MIPS: SMP: Don't increment irq_count multiple times for call function IPIs
  MIPS: Partially disable RIXI support.
  MIPS: Handle page faults of executable but unreadable pages correctly.
  MIPS: Malta: Don't reinitialise RTC
  MIPS: unaligned: Fix build error on big endian R6 kernels
  MIPS: Fix sched_getaffinity with MT FPAFF enabled
  MIPS: Fix build with CONFIG_OF=y for non OF-enabled targets
  CPUFREQ: Loongson2: Fix broken build due to incorrect include.

1 files changed, 13 insertions, 0 deletions

diff --git a/arch/mips/kernel/traps.c b/arch/mips/kernel/traps.c
index e207a43b5f8f..8ea28e6ab37d 100644
--- a/arch/mips/kernel/traps.c
+++ b/arch/mips/kernel/traps.c
@@ -192,6 +192,7 @@ static void show_stacktrace(struct task_struct *task,
 void show_stack(struct task_struct *task, unsigned long *sp)
 {
 	struct pt_regs regs;
+	mm_segment_t old_fs = get_fs();
 	if (sp) {
 		regs.regs[29] = (unsigned long)sp;
 		regs.regs[31] = 0;
@@ -210,7 +211,13 @@ void show_stack(struct task_struct *task, unsigned long *sp)
 			prepare_frametrace(&regs);
 		}
 	}
+	/*
+	 * show_stack() deals exclusively with kernel mode, so be sure to access
+	 * the stack in the kernel (not user) address space.
+	 */
+	set_fs(KERNEL_DS);
 	show_stacktrace(task, &regs);
+	set_fs(old_fs);
 }
 
 static void show_code(unsigned int __user *pc)
@@ -1519,6 +1526,7 @@ asmlinkage void do_mcheck(struct pt_regs *regs)
 	const int field = 2 * sizeof(unsigned long);
 	int multi_match = regs->cp0_status & ST0_TS;
 	enum ctx_state prev_state;
+	mm_segment_t old_fs = get_fs();
 
 	prev_state = exception_enter();
 	show_regs(regs);
@@ -1540,8 +1548,13 @@ asmlinkage void do_mcheck(struct pt_regs *regs)
 		dump_tlb_all();
 	}
 
+	if (!user_mode(regs))
+		set_fs(KERNEL_DS);
+
 	show_code((unsigned int __user *) regs->cp0_epc);
 
+	set_fs(old_fs);
+
 	/*
 	 * Some chips may have other causes of machine check (e.g. SB1
 	 * graduation timer)