Re: [systemd-devel] Antw: Re: Antw: Re: rdrand generated with march=winchip-c6 in systemd-241
Am 13.05.19 um 09:18 schrieb Ulrich Windl: >>> I didn't see the start of this thread, but is it another attempt to >> re-implement /proc/cpuinfo's flags? >> >> can you please stop all that trolling? > > Actually the number of unfriendly words from your side beat mine by an order > of magnitude... it's not about friendly, it's about provocations with little knowledge >> cpuid has *nothing* to do with /proc/cpuinfo >> >> https://en.wikipedia.org/wiki/CPUID >> The CPUID instruction (identified by a CPUID opcode) is a processor >> supplementary instruction > > Isn't it about to check a CPU's feature depending on the CPU model? yes, but you confuse cause and effect, guess from where the kernel output is coming and what you see in /proc/cpuid is just a tiny part of it, just look at the output of the "cpuid" command and compare it with /proc/cpuinfo nobody in binary software digs around in /proc when there are *OPCODES* /proc/cpuid is for you shell scripts why didn't you just read and trying to understand https://en.wikipedia.org/wiki/CPUID ___ systemd-devel mailing list systemd-devel@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/systemd-devel
Re: [systemd-devel] Antw: Re: Antw: Re: rdrand generated with march=winchip-c6 in systemd-241
On Mo, 13.05.19 09:18, Ulrich Windl (ulrich.wi...@rz.uni-regensburg.de) wrote: Please guys, stop it. > > cpuid has *nothing* to do with /proc/cpuinfo > > > > https://en.wikipedia.org/wiki/CPUID > > The CPUID instruction (identified by a CPUID opcode) is a processor > > supplementary instruction > > Isn't it about to check a CPU's feature depending on the CPU model? Ulrich, please understand that __get_cpuid() (which the discussion here is about) is a gcc and llvm/clang feature weare are just making use of. It used by various Linux software, and apparently doesn't work entirely correctly on all CPUs in some corner case. The discussion is about fixing gcc accordingly, and making it work, so that systemd all all other software can work correctly. If you think that gcc/llvm are bad for "reimplementing /proc/cpuinfo" then please bring that up with those communities, but please stop these fruitless discussions here. Thank you for understanding, Lennart -- Lennart Poettering, Berlin ___ systemd-devel mailing list systemd-devel@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/systemd-devel
[systemd-devel] Antw: Re: Antw: Re: rdrand generated with march=winchip-c6 in systemd-241
>>> Reindl Harald schrieb am 13.05.2019 um 09:14 in Nachricht : > > Am 13.05.19 um 09:10 schrieb Ulrich Windl: > tedheadster schrieb am 11.05.2019 um 19:19 in > Nachricht >> : >>> On Sat, May 11, 2019 at 12:30 PM Florian Weimer wrote: Can you capture register contents at the point of the crash? Does this reproduce in a chroot? Maybe you can trace the whole thing with a debugger. Does the crash reproduce if you single-step through the whole function? >>> >>> Florian, >>> I figured out the problem, I just haven't written code to fix it. >>> The documentation I can find is silent about what is returned in %ecx >>> and %ebx when calling cpuid function 0x0001 on IDT Winchip-C6 and >>> Winchip2. >>> >>> I think %ecx should properly contain 0x, but it instead puts >>> the 'auls' characters from cpuid function 0x (vendor string >>> 'CentaurHauls') in %ecx: >>> >>> %ebx = 0x746e6543 = "Cent" >>> %edx = 0x48727561 = "aurH" >>> %ecx = 0x736c7561 = "auls" >>> >>> This sets bit 30 (0x736c7561) 'on', the 'supports rdrand' bit. >>> >>> So we have to code around the vendor and chip model in this case. >>> Jeffrey Walton gave some coding examples I might consider >>> (https://github.com/weidai11/cryptopp/blob/master/cpu.cpp#L380). >> >> >> I didn't see the start of this thread, but is it another attempt to > re-implement /proc/cpuinfo's flags? > > can you please stop all that trolling? Actually the number of unfriendly words from your side beat mine by an order of magnitude... > cpuid has *nothing* to do with /proc/cpuinfo > > https://en.wikipedia.org/wiki/CPUID > The CPUID instruction (identified by a CPUID opcode) is a processor > supplementary instruction Isn't it about to check a CPU's feature depending on the CPU model? Regards, Ulrich ___ systemd-devel mailing list systemd-devel@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/systemd-devel
