MIPS: save/disable MSA in lose_fpu

The kernel depends upon MSA never being enabled when the FPU is not, a
condition which is currently violated in a few places (whilst saving
sigcontext, following mips_cpu_save). Catch all the problem cases by
disabling MSA in lose_fpu, after saving context if necessary.

Signed-off-by: Paul Burton <paul.burton@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/7302/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

diff --git a/arch/mips/include/asm/fpu.h b/arch/mips/include/asm/fpu.h
index a939574f829387c800b4b57de09f94b00c8ef745..71d97ebd9090d68cb503ce4e7a1d08486c7b0bab 100644 (file)
--- a/arch/mips/include/asm/fpu.h
+++ b/arch/mips/include/asm/fpu.h
@@ -21,6 +21,7 @@
 #include <asm/hazards.h>
 #include <asm/processor.h>
 #include <asm/current.h>
+#include <asm/msa.h>
 
 #ifdef CONFIG_MIPS_MT_FPAFF
 #include <asm/mips_mt.h>
@@ -141,13 +142,21 @@ static inline int own_fpu(int restore)
 static inline void lose_fpu(int save)
 {
        preempt_disable();
-       if (is_fpu_owner()) {
+       if (is_msa_enabled()) {
+               if (save) {
+                       save_msa(current);
+                       asm volatile("cfc1 %0, $31"
+                               : "=r"(current->thread.fpu.fcr31));
+               }
+               disable_msa();
+               clear_thread_flag(TIF_USEDMSA);
+       } else if (is_fpu_owner()) {
                if (save)
                        _save_fp(current);
-               KSTK_STATUS(current) &= ~ST0_CU1;
-               clear_thread_flag(TIF_USEDFPU);
                __disable_fpu();
        }
+       KSTK_STATUS(current) &= ~ST0_CU1;
+       clear_thread_flag(TIF_USEDFPU);
        preempt_enable();
 }