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) {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 <linux/bitops.h> #include <linux/bug.h> +#include <linux/elf.h> #include <linux/init.h> #include <linux/kernel.h> #include <linux/personality.h> @@ -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) {------------------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))