address msr bits lost during hard local irq save/restore on non-bookE processors

arch/powerpc/kernel/process.c

@@ -175,6 +175,7 @@ void giveup_fpu(struct task_struct *tsk)
 	msr_check_and_set(MSR_FP);
 	__giveup_fpu(tsk);
 	msr_check_and_clear(MSR_FP);
+	flags &= ~MSR_FP;
     hard_cond_local_irq_restore(flags);
 }
 EXPORT_SYMBOL(giveup_fpu);
@@ -207,6 +208,11 @@ void flush_fp_to_thread(struct task_struct *tsk)
 			 */
 			BUG_ON(tsk != current);
 			giveup_fpu(tsk);
+
+			/* giveup_fpu clears the MSR_FP bit from MSR
+			 * unconditionally
+			 */
+			flags &= ~MSR_FP;
 		}
 		hard_preempt_enable(flags);
 	}
@@ -221,6 +227,7 @@ void enable_kernel_fp(void)
 
     flags = hard_cond_local_irq_save();
 	cpumsr = msr_check_and_set(MSR_FP);
+	flags |= MSR_FP; /* must exit this routine with MSR_FP bit set */
 
 	if (current->thread.regs && (current->thread.regs->msr & MSR_FP)) {
 		check_if_tm_restore_required(current);
@@ -289,6 +296,7 @@ void enable_kernel_altivec(void)
 
     flags = hard_cond_local_irq_save();
 	cpumsr = msr_check_and_set(MSR_VEC);
+	flags |= MSR_VEC; /* must exit this routine with MSR_VEC set in MSR */
 
 	if (current->thread.regs && (current->thread.regs->msr & MSR_VEC)) {
 		check_if_tm_restore_required(current);
@@ -321,6 +329,10 @@ void flush_altivec_to_thread(struct task_struct *tsk)
 		if (tsk->thread.regs->msr & MSR_VEC) {
 			BUG_ON(tsk != current);
 			giveup_altivec(tsk);
+			/* giveup_altivec() clears MSR_VEC
+			 * unconditionally from MSR
+			 */
+			flags &= ~MSR_VEC;
 		}
 		hard_preempt_enable(flags);
 	}
@@ -405,6 +417,10 @@ void flush_vsx_to_thread(struct task_struct *tsk)
 		if (tsk->thread.regs->msr & (MSR_VSX|MSR_VEC|MSR_FP)) {
 			BUG_ON(tsk != current);
 			giveup_vsx(tsk);
+			/* giveup_vsx() clears MSR_FP,VEC,VSX unconditionally
+			 * so clear them in flags
+			 */
+			flags &= ~(MSR_FP|MSR_VEC|MSR_VSX);
 		}
 		hard_preempt_enable(flags);
 	}
@@ -435,6 +451,8 @@ void giveup_spe(struct task_struct *tsk)
 	msr_check_and_set(MSR_SPE);
 	__giveup_spe(tsk);
 	msr_check_and_clear(MSR_SPE);
+	/* must exit this routine with NSR_SPE cleared in MSR */
+	flags &= ~MSR_SPE;
     hard_cond_local_irq_restore(flags);
 }
 EXPORT_SYMBOL(giveup_spe);
@@ -447,7 +465,8 @@ void enable_kernel_spe(void)
 
     flags = hard_cond_local_irq_save();
 	msr_check_and_set(MSR_SPE);
-
+	/* must exit this routine with MSR_SPE set in MSR */
+	flags |= MSR_SPE;
 	if (current->thread.regs && (current->thread.regs->msr & MSR_SPE)) {
 		check_if_tm_restore_required(current);
 		__giveup_spe(current);
@@ -465,6 +484,10 @@ void flush_spe_to_thread(struct task_struct *tsk)
 			BUG_ON(tsk != current);
 			tsk->thread.spefscr = mfspr(SPRN_SPEFSCR);
 			giveup_spe(tsk);
+			/* giveup_spe clears MSR_SPE from MSR, so must clear
+			 * it here to exit rouitine properly
+			 */
+			flags &= MSR_SPE;
 		}
 		hard_preempt_enable(flags);
 	}
@@ -527,6 +550,7 @@ void giveup_all(struct task_struct *tsk)
 #endif
 
 	msr_check_and_clear(msr_all_available);
+	flags &= ~msr_all_available; /* clear all available just in case */
     hard_cond_local_irq_restore(flags);
 }
 EXPORT_SYMBOL(giveup_all);
@@ -559,6 +583,7 @@ void restore_math(struct pt_regs *regs)
 	}
 
 	msr_check_and_clear(msr_all_available);
+	flags &= ~msr_all_available; /* clear all available just in case */
     hard_cond_local_irq_restore(flags);
 
 	regs->msr = msr;
@@ -1224,6 +1249,8 @@ struct task_struct *__switch_to(struct task_struct *prev,
 
 	/* Save FPU, Altivec, VSX and SPE state */
 	giveup_all(prev);
+    /* giveup_all clears msr_all_available bits unconditionally */
+	flags &= ~msr_all_available;
 
 	__switch_to_tm(prev, new);