Protect manipulation of c0_status against preemption and multithreading.

    
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

1 files changed, 16 insertions, 4 deletions

diff --git a/arch/mips/kernel/ptrace32.c b/arch/mips/kernel/ptrace32.c
index c28cdddd4c21..9a9b04972132 100644
--- a/arch/mips/kernel/ptrace32.c
+++ b/arch/mips/kernel/ptrace32.c
@@ -29,6 +29,7 @@
 #include <asm/dsp.h>
 #include <asm/fpu.h>
 #include <asm/mipsregs.h>
+#include <asm/mipsmtregs.h>
 #include <asm/pgtable.h>
 #include <asm/page.h>
 #include <asm/system.h>
@@ -191,10 +192,21 @@ asmlinkage int sys32_ptrace(int request, int pid, int addr, int data)
                         if (!cpu_has_fpu)
                                 break;
 
-                        flags = read_c0_status();
-                        __enable_fpu();
-                        __asm__ __volatile__("cfc1\t%0,$0": "=r" (tmp));
-                        write_c0_status(flags);
+                        preempt_disable();
+                        if (cpu_has_mipsmt) {
+                                unsigned int vpflags = dvpe();
+                                flags = read_c0_status();
+                                __enable_fpu();
+                                __asm__ __volatile__("cfc1\t%0,$0": "=r" (tmp));
+                                write_c0_status(flags);
+                                evpe(vpflags);
+                        } else {
+                                flags = read_c0_status();
+                                __enable_fpu();
+                                __asm__ __volatile__("cfc1\t%0,$0": "=r" (tmp));
+                                write_c0_status(flags);
+                        }
+                        preempt_enable();
                         break;
                 }
                 case DSP_BASE ... DSP_BASE + 5: