Execution problems with Atomic Operations on OpenJDK10 for ARM5 Soft Float

[Fairoz Matte]

Hi Juan Antonio,

> -----Original Message-----
> From: bren at juanantonio.info [mailto:bren at juanantonio.info]
> 
> Good night David,
> 
> It is the first time that I report a Bug on OpenJDK and I didn´t receive any
> notification so I didn´t know the status of the Issue that I reported.

Yes, there was some issue in the notification server, no emails sent to bug submitters. Generally you will receive e-mail, once issue is created in JDK.
Sorry about this.
Thanks David for pointing out the JDK issue.

Thanks,
Fairoz
> 
> Many thanks with the link about the Platforms supported:
> http://www.oracle.com/technetwork/java/javase/documentation/jdk10cert
> config-4417031.html
> 
> We will try to do Compilation with the solution.
> 
> --- a/src/hotspot/cpu/arm/vm_version_arm_32.cpp
> +++ b/src/hotspot/cpu/arm/vm_version_arm_32.cpp
> @@ -298,6 +298,15 @@
>       FLAG_SET_DEFAULT(UseUnalignedAccesses, false);
>     }
> 
> + if (arm_arch() == 5) {
> + if (FLAG_IS_DEFAULT(AssumeMP)) {
> + FLAG_SET_DEFAULT(AssumeMP, false);
> + else if (AssumeMP) {
> + warning("AssumeMP can not be true for ARMv5 as there is only
> uniprocessor support");
> + FLAG_SET_DEFAULT(AssumeMP, false);
> + }
> + }
> +
>     _is_initialized = true;
>   }
> 
> Runtime workaround: java -XX:-AssumeMP
> 
> In our case, I would like to continue maintaining this support for the Device.
> What is the advice that you could give us?
> What is AssumeMP?
> 
> For education, this device is pretty interesting for the whole Java community,
> this is the reason.
> 
> I will inform with the results.
> 
> Many thanks in advance.
> 
> Cheers
> 
> Juan Antonio
> 
> El 2018-04-05 00:12, David Holmes escribió:
> > Hi,
> >
> > This was already reported as:
> >
> > https://bugs.openjdk.java.net/browse/JDK-8200580
> >
> > to which I have responded and closed the bug as this is not a
> > supported platform.
> >
> > As per the bug report this may be due to the change to AssumeMP to be
> > true, but there is no MP support for ARMv5.
> >
> > David
> >
> > On 4/04/2018 8:29 PM, bren at juanantonio.info wrote:
> >> Good morning,
> >>
> >> Mi name is Juan Antonio Breña Moral, I am developing a set of Java
> >> libraries for Lego Mindstorms EV3, an ARM5 robotics device and
> >> recently, we build OpenJDK 9 with success but with OpenJDK 10, we
> >> have found some problems when we execute some Java programs.
> >>
> >> Repository to build OpenJDK 9/10 for ARM5 Soft Float:
> >> https://github.com/ev3dev-lang-java/openjdk-ev3
> >>
> >> To test the JVM, I am using the following repo to test the VM:
> >> https://github.com/ev3dev-lang-java/vmbenchmarks
> >>
> >> And this is the output with the error:
> >>
> >> robot at ev3dev:~$ java -jar benchmarks.jar -f 1
> >> WARNING: An illegal reflective access operation has occurred
> >> WARNING: Illegal reflective access by org.openjdk.jmh.util.Utils
> >> (file:/home/robot/benchmarks.jar) to field java.io.Console.cs
> >> WARNING: Please consider reporting this to the maintainers of
> >> org.openjdk.jmh.util.Utils
> >> WARNING: Use --illegal-access=warn to enable warnings of further
> >> illegal reflective access operations
> >> WARNING: All illegal access operations will be denied in a future
> >> release =============== DEBUG MESSAGE: Atomic load(jlong)
> unsupported
> >> on this platform ================
> >>
> >> =============== DEBUG MESSAGE: Atomic store(jlong) unsupported
> on
> >> this platform ================
> >>
> >>
> >> =============== DEBUG MESSAGE: Atomic load(jlong) unsupported on
> this
> >> platform ================
> >>
> >> [thread 4430 also had an error]
> >> [error occurred during error reporting ((null)), id 0xe0000000]
> >>
> >> =============== DEBUG MESSAGE: Atomic store(jlong) unsupported
> on
> >> this platform ================
> >>
> >>
> >> [error occurred during error reporting (printing fatal error
> >> message), id 0xe0000000]
> >>
> >> =============== DEBUG MESSAGE: Atomic store(jlong) unsupported
> on
> >> this platform ================
> >>
> >>
> >> [error occurred during error reporting (printing type of error), id
> >> 0xe0000000]
> >>
> >> =============== DEBUG MESSAGE: Atomic store(jlong) unsupported
> on
> >> this platform ================
> >>
> >>
> >> [error occurred during error reporting (printing stack bounds), id
> >> 0xe0000000]
> >>
> >> =============== DEBUG MESSAGE: Atomic store(jlong) unsupported
> on
> >> this platform ================
> >>
> >>
> >> [error occurred during error reporting (printing native stack), id
> >> 0xe0000000]
> >>
> >> =============== DEBUG MESSAGE: Atomic store(jlong) unsupported
> on
> >> this platform ================
> >>
> >>
> >> [error occurred during error reporting (printing Java stack), id
> >> 0xe0000000]
> >>
> >> =============== DEBUG MESSAGE: Atomic store(jlong) unsupported
> on
> >> this platform ================
> >>
> >>
> >> [error occurred during error reporting (printing target Java thread
> >> stack), id 0xe0000000]
> >>
> >> =============== DEBUG MESSAGE: Atomic store(jlong) unsupported
> on
> >> this platform ================
> >>
> >>
> >> [error occurred during error reporting (printing siginfo), id
> >> 0xe0000000]
> >>
> >> =============== DEBUG MESSAGE: Atomic store(jlong) unsupported
> on
> >> this platform ================
> >>
> >>
> >> [error occurred during error reporting (CDS archive access warning),
> >> id 0xe0000000]
> >>
> >> =============== DEBUG MESSAGE: Atomic store(jlong) unsupported
> on
> >> this platform ================
> >>
> >>
> >> [error occurred during error reporting (printing register info), id
> >> 0xe0000000]
> >>
> >> =============== DEBUG MESSAGE: Atomic store(jlong) unsupported
> on
> >> this platform ================
> >>
> >>
> >> [Too many errors, abort]
> >> Aborted
> >>
> >> I think that in OpenJDK10 changed something in compare to OpenJDK9 in
> >> relation to ARM5 support.
> >>
> >> Any idea?
> >>
> >> Many thanks in advance.
> >>
> >> Cheers
> >>
> >> Juan Antonio
> >>