| From: Paul Burton <paul.burton@imgtec.com> |
| Date: Fri, 11 Jul 2014 16:44:30 +0100 |
| Subject: MIPS: save/disable MSA in lose_fpu |
| |
| commit 33c771ba5c5d067f85a5a6c4b11047219b5b8f4e upstream. |
| |
| 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> |
| Signed-off-by: Ben Hutchings <ben@decadent.org.uk> |
| Cc: Arnd Bergmann <arnd@arndb.de> |
| --- |
| arch/mips/include/asm/fpu.h | 15 ++++++++++++--- |
| 1 file changed, 12 insertions(+), 3 deletions(-) |
| |
| --- 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(); |
| } |
| |
