The MSA specification upon first read appears to suggest that it is safe
to perform vector loads & stores with arbitrary alignment. However it
leaves provision for "address-dependent exceptions"... Align the vector
context to a 16 byte boundary to ensure that the kernel cannot cause any
such exceptions.
Note that the fpu field of struct thread_struct was already at a 16 byte
boundary within the struct, the introduction of FPU_ALIGN simply makes
the requirement explicit. The only part of this impacting the generated
kernel binary is ARCH_MIN_TASKALIGN.
Signed-off-by: Paul Burton <paul.burton@xxxxxxxxxx>
---
arch/mips/include/asm/processor.h | 10 ++++++++--
1 file changed, 8 insertions(+), 2 deletions(-)
diff --git a/arch/mips/include/asm/processor.h b/arch/mips/include/asm/processor.h
index ad70cba..5733fab 100644
--- a/arch/mips/include/asm/processor.h
+++ b/arch/mips/include/asm/processor.h
@@ -238,7 +238,13 @@ typedef struct {
unsigned long seg;
} mm_segment_t;
-#define ARCH_MIN_TASKALIGN 8
+#ifdef CONFIG_CPU_HAS_MSA
+# define ARCH_MIN_TASKALIGN 16
+# define FPU_ALIGN __aligned(16)
+#else
+# define ARCH_MIN_TASKALIGN 8
+# define FPU_ALIGN
+#endif
struct mips_abi;
@@ -255,7 +261,7 @@ struct thread_struct {
unsigned long cp0_status;
/* Saved fpu/fpu emulator stuff. */
- struct mips_fpu_struct fpu;
+ struct mips_fpu_struct fpu FPU_ALIGN;
#ifdef CONFIG_MIPS_MT_FPAFF
/* Emulated instruction count */
unsigned long emulated_fp;
--
2.0.1
