From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755668AbcETDYo (ORCPT ); Thu, 19 May 2016 23:24:44 -0400 Received: from szxga02-in.huawei.com ([119.145.14.65]:12603 "EHLO szxga02-in.huawei.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752556AbcETDYn (ORCPT ); Thu, 19 May 2016 23:24:43 -0400 Subject: Re: [PATCH] arm64: cpuinfo: add AArch64 & elf platform for app compatibility To: Catalin Marinas References: <1463625873-60016-1-git-send-email-saberlily.xia@hisilicon.com> <20160519104925.GL22378@e104818-lin.cambridge.arm.com> <573D9E40.4000705@hisilicon.com> <20160519125039.GN22378@e104818-lin.cambridge.arm.com> <20160519131832.GO22378@e104818-lin.cambridge.arm.com> CC: Mark Rutland , , , , , , , "Xiaqing (A)" From: "Xiaqing (A)" Message-ID: <573E8300.7060106@hisilicon.com> Date: Fri, 20 May 2016 11:22:40 +0800 User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:38.0) Gecko/20100101 Thunderbird/38.5.1 MIME-Version: 1.0 In-Reply-To: <20160519131832.GO22378@e104818-lin.cambridge.arm.com> Content-Type: text/plain; charset="utf-8"; format=flowed Content-Transfer-Encoding: 8bit X-Originating-IP: [10.184.222.232] X-CFilter-Loop: Reflected X-Mirapoint-Virus-RAPID-Raw: score=unknown(0), refid=str=0001.0A090205.573E830C.00C8,ss=1,re=0.000,recu=0.000,reip=0.000,cl=1,cld=1,fgs=0, ip=0.0.0.0, so=2013-06-18 04:22:30, dmn=2013-03-21 17:37:32 X-Mirapoint-Loop-Id: 4ff57f005206a2384bbcfcdc69387a37 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 在 2016/5/19 21:18, Catalin Marinas 写道: > On Thu, May 19, 2016 at 01:50:40PM +0100, Catalin Marinas wrote: >> On Thu, May 19, 2016 at 07:06:40PM +0800, Xiaqing (A) wrote: >>> >>> >>> 在 2016/5/19 18:49, Catalin Marinas 写道: >>>> On Thu, May 19, 2016 at 10:44:33AM +0800, x00195127 wrote: >>>>> we find that some apps will read cpuinfo when start up, >>>>> they need the string as follows: >>>>> "Processor : AArch64 Processor rev 0 (aarch64)" >>>>> >>>>> Then thay could load the corresponding libs. But now >>>>> arm64 platform's cpuinfo don't has this now, so >>>>> we need add this. >>>> >>>> I have the same question as Martinez: what are those apps? If they are >>>> 64-bit apps, they can always assume AArch64 processor. >>> >>> Those are 32-bit apps, and those apps are very popular in our country. >> >> 32-bit apps checking for "AArch64" is a really silly idea. What do they >> do with this information? >> >> I'm rather inclined to merge this patch: >> >> diff --git a/arch/arm64/kernel/cpuinfo.c b/arch/arm64/kernel/cpuinfo.c >> index 3808470486f3..623d7d291dd6 100644 >> --- a/arch/arm64/kernel/cpuinfo.c >> +++ b/arch/arm64/kernel/cpuinfo.c >> @@ -127,7 +127,8 @@ static int c_show(struct seq_file *m, void *v) >> * software which does already (at least for 32-bit). >> */ >> seq_puts(m, "Features\t:"); >> - if (personality(current->personality) == PER_LINUX32) { >> + if (is_compat_task() || >> + personality(current->personality) == PER_LINUX32) { >> #ifdef CONFIG_COMPAT >> for (j = 0; compat_hwcap_str[j]; j++) >> if (compat_elf_hwcap & (1 << j)) > > To make it even more in line with the AArch32 kernel, let's add the > "model name": > > ------------------8<--------------------- > diff --git a/arch/arm64/kernel/cpuinfo.c b/arch/arm64/kernel/cpuinfo.c > index 3808470486f3..6bda9d30a769 100644 > --- a/arch/arm64/kernel/cpuinfo.c > +++ b/arch/arm64/kernel/cpuinfo.c > @@ -22,6 +22,7 @@ > > #include > #include > +#include > #include > #include > #include > @@ -104,6 +105,8 @@ static const char *const compat_hwcap2_str[] = { > static int c_show(struct seq_file *m, void *v) > { > int i, j; > + bool compat = is_compat_task() || > + personality(current->personality) == PER_LINUX32; > > for_each_online_cpu(i) { > struct cpuinfo_arm64 *cpuinfo = &per_cpu(cpu_data, i); > @@ -115,6 +118,9 @@ static int c_show(struct seq_file *m, void *v) > * "processor". Give glibc what it expects. > */ > seq_printf(m, "processor\t: %d\n", i); > + if (compat) > + seq_printf(m, "model name\t: ARMv8 Processor rev %d (%s)\n", > + MIDR_REVISION(midr), COMPAT_ELF_PLATFORM); > > seq_printf(m, "BogoMIPS\t: %lu.%02lu\n", > loops_per_jiffy / (500000UL/HZ), > @@ -127,7 +133,7 @@ static int c_show(struct seq_file *m, void *v) > * software which does already (at least for 32-bit). > */ > seq_puts(m, "Features\t:"); > - if (personality(current->personality) == PER_LINUX32) { > + if (compat) { > #ifdef CONFIG_COMPAT > for (j = 0; compat_hwcap_str[j]; j++) > if (compat_elf_hwcap & (1 << j)) > ------------------8<--------------------- > > With the above, a compat task or a native one with PER_LINUX32 > personality would get: > > processor : 0 > model name : ARMv8 Processor rev 0 (v8l) > BogoMIPS : 100.00 > Features : half thumb fastmult vfp edsp neon vfpv3 tls vfpv4 idiva idivt lpae evtstrm aes pmull sha1 sha2 crc32 > CPU implementer : 0x41 > CPU architecture: 8 > CPU variant : 0x0 > CPU part : 0xd03 > CPU revision : 0 > I have tested with your patch, the app still can not start up at all. I'm sorry I didn't explan this exactly before, those apps are 32-bit android apps(com.tencent.pao etc.). They want to get the information as "*D m3e : GetCPUType:AArch64 Processor rev 0 (aarch64)*" and I'm sure the process is forked by zygote not zygote64 in android M. Finally, I find that apps need the information "Processor :", so when I change your patch as below, the apps can start up. ---------------------------------------------------------------------- diff --git a/arch/arm64/kernel/cpuinfo.c b/arch/arm64/kernel/cpuinfo.c index 3808470..f14ea4a 100644 --- a/arch/arm64/kernel/cpuinfo.c +++ b/arch/arm64/kernel/cpuinfo.c @@ -104,6 +104,8 @@ static const char *const compat_hwcap2_str[] = { static int c_show(struct seq_file *m, void *v) { int i, j; + bool compat = is_compat_task() || + personality(current->personality) == PER_LINUX32; for_each_online_cpu(i) { struct cpuinfo_arm64 *cpuinfo = &per_cpu(cpu_data, i); @@ -116,6 +118,10 @@ static int c_show(struct seq_file *m, void *v) */ seq_printf(m, "processor\t: %d\n", i); + if (compat) + seq_printf(m, "Processor\t: ARMv8 Processor rev %d (%s)\n", + MIDR_REVISION(midr), COMPAT_ELF_PLATFORM); + seq_printf(m, "BogoMIPS\t: %lu.%02lu\n", loops_per_jiffy / (500000UL/HZ), loops_per_jiffy / (5000UL/HZ) % 100); @@ -127,7 +133,7 @@ static int c_show(struct seq_file *m, void *v) * software which does already (at least for 32-bit). */ seq_puts(m, "Features\t:"); - if (personality(current->personality) == PER_LINUX32) { + if (compat) { #ifdef CONFIG_COMPAT for (j = 0; compat_hwcap_str[j]; j++) if (compat_elf_hwcap & (1 << j))