From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from aserp1040.oracle.com ([141.146.126.69]:50628 "EHLO aserp1040.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932811AbcFCVjL (ORCPT ); Fri, 3 Jun 2016 17:39:11 -0400 From: Sasha Levin To: stable@vger.kernel.org, stable-commits@vger.kernel.org Cc: "Maciej W. Rozycki" , linux-mips@linux-mips.org, Ralf Baechle , Sasha Levin Subject: [added to the 4.1 stable tree] MIPS: MSA: Fix a link error on `_init_msa_upper' with older GCC Date: Fri, 3 Jun 2016 17:36:38 -0400 Message-Id: <1464989831-16666-103-git-send-email-sasha.levin@oracle.com> In-Reply-To: <1464989831-16666-1-git-send-email-sasha.levin@oracle.com> References: <1464989831-16666-1-git-send-email-sasha.levin@oracle.com> Sender: stable-owner@vger.kernel.org List-ID: From: "Maciej W. Rozycki" This patch has been added to the 4.1 stable tree. If you have any objections, please let us know. =============== [ Upstream commit e49d38488515057dba8f0c2ba4cfde5be4a7281f ] Fix a build regression from commit c9017757c532 ("MIPS: init upper 64b of vector registers when MSA is first used"): arch/mips/built-in.o: In function `enable_restore_fp_context': traps.c:(.text+0xbb90): undefined reference to `_init_msa_upper' traps.c:(.text+0xbb90): relocation truncated to fit: R_MIPS_26 against `_init_msa_upper' traps.c:(.text+0xbef0): undefined reference to `_init_msa_upper' traps.c:(.text+0xbef0): relocation truncated to fit: R_MIPS_26 against `_init_msa_upper' to !CONFIG_CPU_HAS_MSA configurations with older GCC versions, which are unable to figure out that calls to `_init_msa_upper' are indeed dead. Of the many ways to tackle this failure choose the approach we have already taken in `thread_msa_context_live'. [ralf@linux-mips.org: Drop patch segment to junk file.] Signed-off-by: Maciej W. Rozycki Cc: stable@vger.kernel.org # v3.16+ Cc: linux-mips@linux-mips.org Patchwork: https://patchwork.linux-mips.org/patch/13271/ Signed-off-by: Ralf Baechle Signed-off-by: Sasha Levin --- arch/mips/include/asm/msa.h | 13 +++++++++++++ arch/mips/kernel/traps.c | 6 +++--- 2 files changed, 16 insertions(+), 3 deletions(-) diff --git a/arch/mips/include/asm/msa.h b/arch/mips/include/asm/msa.h index af5638b..38bbeda 100644 --- a/arch/mips/include/asm/msa.h +++ b/arch/mips/include/asm/msa.h @@ -67,6 +67,19 @@ static inline void restore_msa(struct task_struct *t) _restore_msa(t); } +static inline void init_msa_upper(void) +{ + /* + * Check cpu_has_msa only if it's a constant. This will allow the + * compiler to optimise out code for CPUs without MSA without adding + * an extra redundant check for CPUs with MSA. + */ + if (__builtin_constant_p(cpu_has_msa) && !cpu_has_msa) + return; + + _init_msa_upper(); +} + #ifdef TOOLCHAIN_SUPPORTS_MSA #define __BUILD_MSA_CTL_REG(name, cs) \ diff --git a/arch/mips/kernel/traps.c b/arch/mips/kernel/traps.c index b274541..7440395 100644 --- a/arch/mips/kernel/traps.c +++ b/arch/mips/kernel/traps.c @@ -1228,7 +1228,7 @@ static int enable_restore_fp_context(int msa) err = init_fpu(); if (msa && !err) { enable_msa(); - _init_msa_upper(); + init_msa_upper(); set_thread_flag(TIF_USEDMSA); set_thread_flag(TIF_MSA_CTX_LIVE); } @@ -1291,7 +1291,7 @@ static int enable_restore_fp_context(int msa) */ prior_msa = test_and_set_thread_flag(TIF_MSA_CTX_LIVE); if (!prior_msa && was_fpu_owner) { - _init_msa_upper(); + init_msa_upper(); goto out; } @@ -1308,7 +1308,7 @@ static int enable_restore_fp_context(int msa) * of each vector register such that it cannot see data left * behind by another task. */ - _init_msa_upper(); + init_msa_upper(); } else { /* We need to restore the vector context. */ restore_msa(current); -- 2.5.0