From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.linuxfoundation.org ([140.211.169.12]:60754 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932688AbdK1Knr (ORCPT ); Tue, 28 Nov 2017 05:43:47 -0500 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Ben Hutchings , Ralf Baechle , Deng-Cheng Zhu , linux-mips@linux-mips.org, James Hogan Subject: [PATCH 4.14 023/193] MIPS: cmpxchg64() and HAVE_VIRT_CPU_ACCOUNTING_GEN dont work for 32-bit SMP Date: Tue, 28 Nov 2017 11:24:30 +0100 Message-Id: <20171128100614.611270137@linuxfoundation.org> In-Reply-To: <20171128100613.638270407@linuxfoundation.org> References: <20171128100613.638270407@linuxfoundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: stable-owner@vger.kernel.org List-ID: 4.14-stable review patch. If anyone has any objections, please let me know. ------------------ From: Ben Hutchings commit a3f143106596d739e7fbc4b84c96b1475247d876 upstream. __cmpxchg64_local_generic() is atomic only w.r.t tasks and interrupts on the same CPU (that's what the 'local' means). We can't use it to implement cmpxchg64() in SMP configurations. So, for 32-bit SMP configurations: - Don't define cmpxchg64() - Don't enable HAVE_VIRT_CPU_ACCOUNTING_GEN, which requires it Fixes: e2093c7b03c1 ("MIPS: Fall back to generic implementation of ...") Fixes: bb877e96bea1 ("MIPS: Add support for full dynticks CPU time accounting") Signed-off-by: Ben Hutchings Cc: Ralf Baechle Cc: Deng-Cheng Zhu Cc: linux-mips@linux-mips.org Patchwork: https://patchwork.linux-mips.org/patch/17413/ Signed-off-by: James Hogan Signed-off-by: Greg Kroah-Hartman --- arch/mips/Kconfig | 2 +- arch/mips/include/asm/cmpxchg.h | 2 ++ 2 files changed, 3 insertions(+), 1 deletion(-) --- a/arch/mips/Kconfig +++ b/arch/mips/Kconfig @@ -65,7 +65,7 @@ config MIPS select HAVE_PERF_EVENTS select HAVE_REGS_AND_STACK_ACCESS_API select HAVE_SYSCALL_TRACEPOINTS - select HAVE_VIRT_CPU_ACCOUNTING_GEN + select HAVE_VIRT_CPU_ACCOUNTING_GEN if 64BIT || !SMP select IRQ_FORCED_THREADING select MODULES_USE_ELF_RELA if MODULES && 64BIT select MODULES_USE_ELF_REL if MODULES --- a/arch/mips/include/asm/cmpxchg.h +++ b/arch/mips/include/asm/cmpxchg.h @@ -204,8 +204,10 @@ static inline unsigned long __cmpxchg(vo #else #include #define cmpxchg64_local(ptr, o, n) __cmpxchg64_local_generic((ptr), (o), (n)) +#ifndef CONFIG_SMP #define cmpxchg64(ptr, o, n) cmpxchg64_local((ptr), (o), (n)) #endif +#endif #undef __scbeqz