From 36d632ea831fd2fa3cb62599a465825f59076f64 Mon Sep 17 00:00:00 2001
From: Nicholas Piggin <npiggin@gmail.com>
Date: Sat, 5 May 2018 03:19:29 +1000
Subject: [PATCH] powerpc/64: remove start_tb and accum_tb from thread_struct

References: bsc#1186487 ltc#177613
Patch-mainline: v4.18-rc1
Git-commit: 36d632ea831fd2fa3cb62599a465825f59076f64

These fields are only written to.

Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Acked-by: Michal Suchanek <msuchanek@suse.de>
---
 arch/powerpc/include/asm/processor.h | 4 ----
 arch/powerpc/kernel/process.c        | 6 +-----
 2 files changed, 1 insertion(+), 9 deletions(-)

diff --git a/arch/powerpc/include/asm/processor.h b/arch/powerpc/include/asm/processor.h
index c4b36a494a63..eff269adfa71 100644
--- a/arch/powerpc/include/asm/processor.h
+++ b/arch/powerpc/include/asm/processor.h
@@ -264,10 +264,6 @@ struct thread_struct {
 	struct thread_fp_state	*fp_save_area;
 	int		fpexc_mode;	/* floating-point exception mode */
 	unsigned int	align_ctl;	/* alignment handling control */
-#ifdef CONFIG_PPC64
-	unsigned long	start_tb;	/* Start purr when proc switched in */
-	unsigned long	accum_tb;	/* Total accumulated purr for process */
-#endif
 #ifdef CONFIG_HAVE_HW_BREAKPOINT
 	struct perf_event *ptrace_bps[HBP_NUM];
 	/*
diff --git a/arch/powerpc/kernel/process.c b/arch/powerpc/kernel/process.c
index 25db000fa5b3..f4e5291584c5 100644
--- a/arch/powerpc/kernel/process.c
+++ b/arch/powerpc/kernel/process.c
@@ -1188,11 +1188,7 @@ struct task_struct *__switch_to(struct task_struct *prev,
 	 */
 	if (firmware_has_feature(FW_FEATURE_SPLPAR)) {
 		struct cpu_usage *cu = this_cpu_ptr(&cpu_usage_array);
-		long unsigned start_tb, current_tb;
-		start_tb = old_thread->start_tb;
-		cu->current_tb = current_tb = mfspr(SPRN_PURR);
-		old_thread->accum_tb += (current_tb - start_tb);
-		new_thread->start_tb = current_tb;
+		cu->current_tb = mfspr(SPRN_PURR);
 	}
 #endif /* CONFIG_PPC64 */
 
-- 
2.26.2