From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from ozlabs.org (ozlabs.org [IPv6:2401:3900:2:1::2]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 977491A1B18 for ; Mon, 20 Apr 2015 18:16:58 +1000 (AEST) Received: from e23smtp03.au.ibm.com (e23smtp03.au.ibm.com [202.81.31.145]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by ozlabs.org (Postfix) with ESMTPS id 2923C14027F for ; Mon, 20 Apr 2015 18:16:58 +1000 (AEST) Received: from /spool/local by e23smtp03.au.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Mon, 20 Apr 2015 18:16:55 +1000 Received: from d23relay06.au.ibm.com (d23relay06.au.ibm.com [9.185.63.219]) by d23dlp02.au.ibm.com (Postfix) with ESMTP id 8AE812BB0040 for ; Mon, 20 Apr 2015 18:16:53 +1000 (EST) Received: from d23av02.au.ibm.com (d23av02.au.ibm.com [9.190.235.138]) by d23relay06.au.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id t3K8GiIR49021156 for ; Mon, 20 Apr 2015 18:16:53 +1000 Received: from d23av02.au.ibm.com (localhost [127.0.0.1]) by d23av02.au.ibm.com (8.14.4/8.14.4/NCO v10.0 AVout) with ESMTP id t3K8GJIx021495 for ; Mon, 20 Apr 2015 18:16:19 +1000 From: Anshuman Khandual To: linuxppc-dev@ozlabs.org Subject: [RFC] powerpc, tm: Drop tm_orig_msr from thread_struct Date: Mon, 20 Apr 2015 13:45:54 +0530 Message-Id: <1429517754-7988-1-git-send-email-khandual@linux.vnet.ibm.com> Cc: mikey@neuling.org, paulus@samba.org List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Currently tm_orig_msr is getting used during process context switch only. Then there is ckpt_regs which saves the checkpointed userspace context The MSR slot contained in ckpt_regs structure can be used during process context switch instead of tm_orig_msr, thus allowing us to drop it from thread_struct structure. This patch does that change. Signed-off-by: Anshuman Khandual --- This issue came up in the discussion regarding ptrace interface for TM specific registers https://lkml.org/lkml/2015/4/20/100, so just wanted to give this a try. The basic TM tests still pass after this change. arch/powerpc/include/asm/processor.h | 1 - arch/powerpc/kernel/process.c | 14 +++++++------- 2 files changed, 7 insertions(+), 8 deletions(-) diff --git a/arch/powerpc/include/asm/processor.h b/arch/powerpc/include/asm/processor.h index bf117d8..fc2a3135 100644 --- a/arch/powerpc/include/asm/processor.h +++ b/arch/powerpc/include/asm/processor.h @@ -264,7 +264,6 @@ struct thread_struct { u64 tm_tfhar; /* Transaction fail handler addr */ u64 tm_texasr; /* Transaction exception & summary */ u64 tm_tfiar; /* Transaction fail instr address reg */ - unsigned long tm_orig_msr; /* Thread's MSR on ctx switch */ struct pt_regs ckpt_regs; /* Checkpointed registers */ unsigned long tm_tar; diff --git a/arch/powerpc/kernel/process.c b/arch/powerpc/kernel/process.c index febb50d..654830a 100644 --- a/arch/powerpc/kernel/process.c +++ b/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); } @@ -543,7 +543,7 @@ 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)); @@ -594,10 +594,10 @@ 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", @@ -666,7 +666,7 @@ 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", @@ -726,7 +726,7 @@ 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(); -- 1.9.3