MIPS: Cavium OCTEON multiplier state preservation.
For OCTEON, implement a save and restore of the multiplier state
across context switches.
Signed-off-by: Tomaso Paoletti <tpaoletti@caviumnetworks.com>
Signed-off-by: David Daney <ddaney@caviumnetworks.com>
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
diff --git a/arch/mips/include/asm/stackframe.h b/arch/mips/include/asm/stackframe.h
index 4c37c4e5..db0fa7b 100644
--- a/arch/mips/include/asm/stackframe.h
+++ b/arch/mips/include/asm/stackframe.h
@@ -194,6 +194,19 @@
LONG_S $31, PT_R31(sp)
ori $28, sp, _THREAD_MASK
xori $28, _THREAD_MASK
+#ifdef CONFIG_CPU_CAVIUM_OCTEON
+ .set mips64
+ pref 0, 0($28) /* Prefetch the current pointer */
+ pref 0, PT_R31(sp) /* Prefetch the $31(ra) */
+ /* The Octeon multiplier state is affected by general multiply
+ instructions. It must be saved before and kernel code might
+ corrupt it */
+ jal octeon_mult_save
+ LONG_L v1, 0($28) /* Load the current pointer */
+ /* Restore $31(ra) that was changed by the jal */
+ LONG_L ra, PT_R31(sp)
+ pref 0, 0(v1) /* Prefetch the current thread */
+#endif
.set pop
.endm
@@ -324,6 +337,10 @@
DVPE 5 # dvpe a1
jal mips_ihb
#endif /* CONFIG_MIPS_MT_SMTC */
+#ifdef CONFIG_CPU_CAVIUM_OCTEON
+ /* Restore the Octeon multiplier state */
+ jal octeon_mult_restore
+#endif
mfc0 a0, CP0_STATUS
ori a0, STATMASK
xori a0, STATMASK