diff options
Diffstat (limited to 'arch/powerpc/kernel/signal_64.c')
| -rw-r--r-- | arch/powerpc/kernel/signal_64.c | 20 |
1 files changed, 18 insertions, 2 deletions
diff --git a/arch/powerpc/kernel/signal_64.c b/arch/powerpc/kernel/signal_64.c index c83c115858c1..4b9ca3570344 100644 --- a/arch/powerpc/kernel/signal_64.c +++ b/arch/powerpc/kernel/signal_64.c @@ -214,6 +214,8 @@ static long setup_tm_sigcontexts(struct sigcontext __user *sc, BUG_ON(!MSR_TM_ACTIVE(regs->msr)); + WARN_ON(tm_suspend_disabled); + /* Remove TM bits from thread's MSR. The MSR in the sigcontext * just indicates to userland that we were doing a transaction, but we * don't want to return in transactional state. This also ensures @@ -430,6 +432,9 @@ static long restore_tm_sigcontexts(struct task_struct *tsk, BUG_ON(tsk != current); + if (tm_suspend_disabled) + return -EINVAL; + /* copy the GPRs */ err |= __copy_from_user(regs->gpr, tm_sc->gp_regs, sizeof(regs->gpr)); err |= __copy_from_user(&tsk->thread.ckpt_regs, sc->gp_regs, @@ -452,9 +457,20 @@ static long restore_tm_sigcontexts(struct task_struct *tsk, if (MSR_TM_RESV(msr)) return -EINVAL; - /* pull in MSR TM from user context */ + /* pull in MSR TS bits from user context */ regs->msr = (regs->msr & ~MSR_TS_MASK) | (msr & MSR_TS_MASK); + /* + * Ensure that TM is enabled in regs->msr before we leave the signal + * handler. It could be the case that (a) user disabled the TM bit + * through the manipulation of the MSR bits in uc_mcontext or (b) the + * TM bit was disabled because a sufficient number of context switches + * happened whilst in the signal handler and load_tm overflowed, + * disabling the TM bit. In either case we can end up with an illegal + * TM state leading to a TM Bad Thing when we return to userspace. + */ + regs->msr |= MSR_TM; + /* pull in MSR LE from user context */ regs->msr = (regs->msr & ~MSR_LE) | (msr & MSR_LE); @@ -547,7 +563,7 @@ static long restore_tm_sigcontexts(struct task_struct *tsk, /* Make sure the transaction is marked as failed */ tsk->thread.tm_texasr |= TEXASR_FS; /* This loads the checkpointed FP/VEC state, if used */ - tm_recheckpoint(&tsk->thread, msr); + tm_recheckpoint(&tsk->thread); msr_check_and_set(msr & (MSR_FP | MSR_VEC)); if (msr & MSR_FP) { |