diff options
Diffstat (limited to 'arch/mips/kernel/traps.c')
| -rw-r--r-- | arch/mips/kernel/traps.c | 39 |
1 files changed, 30 insertions, 9 deletions
diff --git a/arch/mips/kernel/traps.c b/arch/mips/kernel/traps.c index 649c151fe1db..1ed84577d3e3 100644 --- a/arch/mips/kernel/traps.c +++ b/arch/mips/kernel/traps.c @@ -1089,13 +1089,15 @@ static int default_cu2_call(struct notifier_block *nfb, unsigned long action, static int enable_restore_fp_context(int msa) { - int err, was_fpu_owner; + int err, was_fpu_owner, prior_msa; if (!used_math()) { /* First time FP context user. */ err = init_fpu(); - if (msa && !err) + if (msa && !err) { enable_msa(); + _init_msa_upper(); + } if (!err) set_used_math(); return err; @@ -1147,18 +1149,37 @@ static int enable_restore_fp_context(int msa) /* * If this is the first time that the task is using MSA and it has * previously used scalar FP in this time slice then we already nave - * FP context which we shouldn't clobber. + * FP context which we shouldn't clobber. We do however need to clear + * the upper 64b of each vector register so that this task has no + * opportunity to see data left behind by another. */ - if (!test_and_set_thread_flag(TIF_MSA_CTX_LIVE) && was_fpu_owner) + prior_msa = test_and_set_thread_flag(TIF_MSA_CTX_LIVE); + if (!prior_msa && was_fpu_owner) { + _init_msa_upper(); return 0; + } - /* We need to restore the vector context. */ - restore_msa(current); + if (!prior_msa) { + /* + * Restore the least significant 64b of each vector register + * from the existing scalar FP context. + */ + _restore_fp(current); - /* Restore the scalar FP control & status register */ - if (!was_fpu_owner) - asm volatile("ctc1 %0, $31" : : "r"(current->thread.fpu.fcr31)); + /* + * The task has not formerly used MSA, so clear the upper 64b + * of each vector register such that it cannot see data left + * behind by another task. + */ + _init_msa_upper(); + } else { + /* We need to restore the vector context. */ + restore_msa(current); + /* Restore the scalar FP control & status register */ + if (!was_fpu_owner) + asm volatile("ctc1 %0, $31" : : "r"(current->thread.fpu.fcr31)); + } return 0; } |