From b08f711c1f479a75639cd37127fab3312959c155 Mon Sep 17 00:00:00 2001 From: "Gautham R. Shenoy" Date: Mon, 27 Feb 2017 11:10:07 +0530 Subject: [PATCH 6/6] powerpc/powernv: Fix bug due to labeling ambiguity in power_enter_stop Commit 09206b600c76 ("powernv: Pass PSSCR value and mask to power9_idle_stop") added additional code in power_enter_stop() to distinguish between stop requests whose PSSCR had ESL=EC=1 from those which did not. When ESL=EC=1, we do a forward-jump to a location labelled by "1", which had the code to handle the ESL=EC=1 case. Unfortunately just a couple of instructions before this label, is the macro IDLE_STATE_ENTER_SEQ() which also has a label "1" in its expansion. As a result, the current code can result in directly executing stop instruction for deep stop requests with PSSCR ESL=EC=1, without saving the hypervisor state. Fix this BUG by labeling the location that handles ESL=EC=1 case with a more descriptive label ".Lhandle_esl_ec_set" (local label suggestion a la .Lxx from Anton Blanchard). While at it, rename the label "2" labelling the location of the code handling entry into deep stop states with ".Lhandle_deep_stop". For a good measure, change the label in IDLE_STATE_ENTER_SEQ() macro to an not-so commonly used value in order to avoid similar mishaps in the future. Cherry-picked from commit 424f8acd328a ("powerpc/powernv: Fix bug due to labeling ambiguity in power_enter_stop") Fixes: 09206b600c76 ("powernv: Pass PSSCR value and mask to power9_idle_stop") Signed-off-by: Gautham R. Shenoy Signed-off-by: Michael Ellerman --- arch/powerpc/include/asm/cpuidle.h | 4 ++-- arch/powerpc/kernel/idle_book3s.S | 10 ++++++---- 2 files changed, 8 insertions(+), 6 deletions(-) diff --git a/arch/powerpc/include/asm/cpuidle.h b/arch/powerpc/include/asm/cpuidle.h index 65d8078..82ea83d 100644 --- a/arch/powerpc/include/asm/cpuidle.h +++ b/arch/powerpc/include/asm/cpuidle.h @@ -70,8 +70,8 @@ static inline void report_invalid_psscr_val(u64 psscr_val, int err) std r0,0(r1); \ ptesync; \ ld r0,0(r1); \ -1: cmpd cr0,r0,r0; \ - bne 1b; \ +236: cmpd cr0,r0,r0; \ + bne 236b; \ IDLE_INST; \ #define IDLE_STATE_ENTER_SEQ_NORET(IDLE_INST) \ diff --git a/arch/powerpc/kernel/idle_book3s.S b/arch/powerpc/kernel/idle_book3s.S index 4f6cf55..4724ccc 100644 --- a/arch/powerpc/kernel/idle_book3s.S +++ b/arch/powerpc/kernel/idle_book3s.S @@ -276,19 +276,21 @@ power_enter_stop: */ andis. r4,r3,PSSCR_EC_ESL_MASK_SHIFTED clrldi r3,r3,60 /* r3 = Bits[60:63] = Requested Level (RL) */ - bne 1f + bne .Lhandle_esl_ec_set IDLE_STATE_ENTER_SEQ(PPC_STOP) li r3,0 /* Since we didn't lose state, return 0 */ b pnv_wakeup_noloss + +.Lhandle_esl_ec_set: /* * Check if the requested state is a deep idle state. */ -1: LOAD_REG_ADDRBASE(r5,pnv_first_deep_stop_state) + LOAD_REG_ADDRBASE(r5,pnv_first_deep_stop_state) ld r4,ADDROFF(pnv_first_deep_stop_state)(r5) cmpd r3,r4 - bge 2f + bge .Lhandle_deep_stop IDLE_STATE_ENTER_SEQ_NORET(PPC_STOP) -2: +.Lhandle_deep_stop: /* * Entering deep idle state. * Clear thread bit in PACA_CORE_IDLE_STATE, save SPRs to -- 1.9.4