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On 2019.09.10 21:44, Michał Górny wrote: |
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> Hi, everyone. |
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> |
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> I've recently (finally!) started adding tests to cpuid2cpuflags. |
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> Tests |
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> are based on mocked syscalls that return arch-specific data read from |
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> text files. So far I've got x86 and ppc covered, and now I'd like to |
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> add tests for various arm hardware. Since ARM covers a pretty broad |
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> range of hardware, I'd use as much data as possible, especially from |
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> different ARM generations. |
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> |
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> If you have an ARM board and would like to help, please: |
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> |
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> wget https://dev.gentoo.org/~mgorny/dist/cpuid2cpuflags-7-dev.tar.bz2 |
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> tar -xf cpuid2cpuflags-7-dev.tar.bz2 |
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> cd cpuid2cpuflags-7-dev |
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> ./configure |
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> make hwcap-dump |
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> ./hwcap-dump |
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> |
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> and send me the output along with 'uname -m'. TIA! |
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> |
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> -- |
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> Best regards, |
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> Michał Górny |
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> |
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> |
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|
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Team, this is going to be a long rambling tale of woe. Sorry in advance. |
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On arm64 cpuid2cpuflags-8 tells me |
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|
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Pi4_~arm64 /usr/portage # cpuid2cpuflags |
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CPU_FLAGS_ARM: edsp neon thumb vfp vfpv3 vfpv4 vfp-d32 crc32 v4 v5 v6 v7 v8 thumb2 |
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|
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but by chance I hit |
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[Bug 695854] net-misc/freerdp-2.0.0_rc4 on arm64 - aarch64-unknown-linux-gnu-gcc: error: unrecognized command line option ‘-mfpu=neon’ |
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|
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The 32 bit arm instruction set is optional on arm64. |
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The 64 bit Raspberry Pis all have it |
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The Cavium Thunder does not. |
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|
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It is unlikely that there will ever be a multilib arm64. Only a subset |
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of arm64 could ever support it, so should we be using CPU_FLAGS_ARM |
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to cover arm64 too? |
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|
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There is nothing in the name. Its the content that matters. |
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|
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On a Pi4 in 64 bit mode, cpuinfo shows |
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Pi4_~arm64 /usr/portage # cat /proc/cpuinfo |
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processor : 0 |
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BogoMIPS : 108.00 |
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Features : fp asimd evtstrm crc32 cpuid |
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CPU implementer : 0x41 |
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CPU architecture: 8 |
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CPU variant : 0x0 |
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CPU part : 0xd08 |
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CPU revision : 3 |
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|
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In 32 bit mode, the same CPU shows |
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$ cat pi4_32.txt |
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processor : 0 |
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model name : ARMv7 Processor rev 3 (v7l) |
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BogoMIPS : 108.00 |
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Features : half thumb fastmult vfp edsp neon vfpv3 tls vfpv4 idiva idivt vfpd32 lpae evtstrm crc32 |
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CPU implementer : 0x41 |
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CPU architecture: 7 |
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CPU variant : 0x0 |
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CPU part : 0xd08 |
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CPU revision : 3 |
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|
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|
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Cavium (64 bit) |
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arm64-build / # cat /proc/cpuinfo |
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processor : 0 |
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BogoMIPS : 200.00 |
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Features : fp asimd evtstrm aes pmull sha1 sha2 crc32 |
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CPU implementer : 0x43 |
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CPU architecture: 8 |
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CPU variant : 0x1 |
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CPU part : 0x0a1 |
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CPU revision : 1 |
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|
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The Cavium does not have any 32 bit instructions. |
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|
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From bug 695854, CPU_FLAGS_ARM: neon is not correct on the Cavium. |
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I suspect that the other 32 bit flags will fail there, as it does not have them |
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but they might work on the Pi, as it does. |
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|
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Other than pointing out the problem, I don't know how to test further. |
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Guidance welcome. |
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|
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-- |
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Regards, |
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|
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Roy Bamford |
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(Neddyseagoon) a member of |
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elections |
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gentoo-ops |
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forum-mods |
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arm64 |
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