These changes are the raw update to linux-4.4.6-rt14. Kernel sources

[kvmfornfv.git] / kernel / arch / powerpc / kernel / process.c

diff --git a/kernel/arch/powerpc/kernel/process.c b/kernel/arch/powerpc/kernel/process.c
index 0596373..ef2ad2d 100644 (file)
--- a/kernel/arch/powerpc/kernel/process.c
+++ b/kernel/arch/powerpc/kernel/process.c
@@ -86,7 +86,7 @@ void giveup_fpu_maybe_transactional(struct task_struct *tsk)
        if (tsk == current && tsk->thread.regs &&
            MSR_TM_ACTIVE(tsk->thread.regs->msr) &&
            !test_thread_flag(TIF_RESTORE_TM)) {
-               tsk->thread.tm_orig_msr = tsk->thread.regs->msr;
+               tsk->thread.ckpt_regs.msr = tsk->thread.regs->msr;
                set_thread_flag(TIF_RESTORE_TM);
        }
 
@@ -104,7 +104,7 @@ void giveup_altivec_maybe_transactional(struct task_struct *tsk)
        if (tsk == current && tsk->thread.regs &&
            MSR_TM_ACTIVE(tsk->thread.regs->msr) &&
            !test_thread_flag(TIF_RESTORE_TM)) {
-               tsk->thread.tm_orig_msr = tsk->thread.regs->msr;
+               tsk->thread.ckpt_regs.msr = tsk->thread.regs->msr;
                set_thread_flag(TIF_RESTORE_TM);
        }
 
@@ -540,7 +540,7 @@ static void tm_reclaim_thread(struct thread_struct *thr,
         * the thread will no longer be transactional.
         */
        if (test_ti_thread_flag(ti, TIF_RESTORE_TM)) {
-               msr_diff = thr->tm_orig_msr & ~thr->regs->msr;
+               msr_diff = thr->ckpt_regs.msr & ~thr->regs->msr;
                if (msr_diff & MSR_FP)
                        memcpy(&thr->transact_fp, &thr->fp_state,
                               sizeof(struct thread_fp_state));
@@ -551,6 +551,42 @@ static void tm_reclaim_thread(struct thread_struct *thr,
                msr_diff &= MSR_FP | MSR_VEC | MSR_VSX | MSR_FE0 | MSR_FE1;
        }
 
+       /*
+        * Use the current MSR TM suspended bit to track if we have
+        * checkpointed state outstanding.
+        * On signal delivery, we'd normally reclaim the checkpointed
+        * state to obtain stack pointer (see:get_tm_stackpointer()).
+        * This will then directly return to userspace without going
+        * through __switch_to(). However, if the stack frame is bad,
+        * we need to exit this thread which calls __switch_to() which
+        * will again attempt to reclaim the already saved tm state.
+        * Hence we need to check that we've not already reclaimed
+        * this state.
+        * We do this using the current MSR, rather tracking it in
+        * some specific thread_struct bit, as it has the additional
+        * benifit of checking for a potential TM bad thing exception.
+        */
+       if (!MSR_TM_SUSPENDED(mfmsr()))
+               return;
+
+       /*
+        * Use the current MSR TM suspended bit to track if we have
+        * checkpointed state outstanding.
+        * On signal delivery, we'd normally reclaim the checkpointed
+        * state to obtain stack pointer (see:get_tm_stackpointer()).
+        * This will then directly return to userspace without going
+        * through __switch_to(). However, if the stack frame is bad,
+        * we need to exit this thread which calls __switch_to() which
+        * will again attempt to reclaim the already saved tm state.
+        * Hence we need to check that we've not already reclaimed
+        * this state.
+        * We do this using the current MSR, rather tracking it in
+        * some specific thread_struct bit, as it has the additional
+        * benifit of checking for a potential TM bad thing exception.
+        */
+       if (!MSR_TM_SUSPENDED(mfmsr()))
+               return;
+
        tm_reclaim(thr, thr->regs->msr, cause);
 
        /* Having done the reclaim, we now have the checkpointed
@@ -591,10 +627,10 @@ static inline void tm_reclaim_task(struct task_struct *tsk)
        /* Stash the original thread MSR, as giveup_fpu et al will
         * modify it.  We hold onto it to see whether the task used
         * FP & vector regs.  If the TIF_RESTORE_TM flag is set,
-        * tm_orig_msr is already set.
+        * ckpt_regs.msr is already set.
         */
        if (!test_ti_thread_flag(task_thread_info(tsk), TIF_RESTORE_TM))
-               thr->tm_orig_msr = thr->regs->msr;
+               thr->ckpt_regs.msr = thr->regs->msr;
 
        TM_DEBUG("--- tm_reclaim on pid %d (NIP=%lx, "
                 "ccr=%lx, msr=%lx, trap=%lx)\n",
@@ -663,7 +699,7 @@ static inline void tm_recheckpoint_new_task(struct task_struct *new)
                tm_restore_sprs(&new->thread);
                return;
        }
-       msr = new->thread.tm_orig_msr;
+       msr = new->thread.ckpt_regs.msr;
        /* Recheckpoint to restore original checkpointed register state. */
        TM_DEBUG("*** tm_recheckpoint of pid %d "
                 "(new->msr 0x%lx, new->origmsr 0x%lx)\n",
@@ -723,7 +759,7 @@ void restore_tm_state(struct pt_regs *regs)
        if (!MSR_TM_ACTIVE(regs->msr))
                return;
 
-       msr_diff = current->thread.tm_orig_msr & ~regs->msr;
+       msr_diff = current->thread.ckpt_regs.msr & ~regs->msr;
        msr_diff &= MSR_FP | MSR_VEC | MSR_VSX;
        if (msr_diff & MSR_FP) {
                fp_enable();
@@ -1109,7 +1145,6 @@ static void setup_ksp_vsid(struct task_struct *p, unsigned long sp)
 /*
  * Copy a thread..
  */
-extern unsigned long dscr_default; /* defined in arch/powerpc/kernel/sysfs.c */
 
 /*
  * Copy architecture-specific thread state