Forward the missing messages. ---------- Forwarded message ---------- From: 王昊然 <msl0000023...@gmail.com> Date: Fri, 21 Oct 2022 14:09:33 +0800 Subject: Re: Bug#1022049: libnettle8: Illegal instruction on IBM POWER7 To: Maamoun TK <maamoun...@googlemail.com> Cc: Niels Möller <ni...@lysator.liu.se>
I can confirm this patch worked on my system. 2022-10-20 21:02 GMT+08:00, Maamoun TK <maamoun...@googlemail.com>: > On Wed, Oct 19, 2022 at 6:22 PM Maamoun TK <maamoun...@googlemail.com> > wrote: > >> On Wed, Oct 19, 2022 at 5:50 PM Niels Möller <ni...@lysator.liu.se> >> wrote: >> >>> WHR <msl0000023...@gmail.com> writes: >>> >>> > I think the Debian architecture I'm using (ppc64) should still >>> supporting >>> > POWER7, but apparently this library was built to use instructions >>> unavailable >>> > on POWER7. >>> >>> Nettle attempts to figure out at runtime which processor features are >>> available. >>> >>> > => 0x00003fffb72bedec <+76>: vmrgow v4,v0,v0 >>> >>> The ppc specification says "vmrgow is treated as a Vector >>> instruction in terms of resource availability.", it's not entirely clear >>> to me what that means, and if checking for altivec support should be >>> enough. >>> >> >> I don't have access to log file or bug report but I'm assuming that the >> usage of "vmrgow/vmrgew" in chacha-2core.asm triggers this bug since both >> instructions are only available on POWER8+ >> >> I'll investigate more about the issue besides the possibility of >> utilizing >> "vmrghw/vmrglw" instead. >> > > It seems only the usage of "vmrgow/vmrgew" causes the issue. I pushed a MR > to the main repository that resolves the bug > https://git.lysator.liu.se/nettle/nettle/-/merge_requests/54 > Tested on POWER7 machines in little-endian and big-endian modes. > > regards, > Mamone > > >> regards, >> Mamone >> >> The fat setup for ppc is intended to enable the crashing code path only >>> if the feature bits PPC_FEATURE_HAS_ALTIVEC and PPC_FEATURE_HAS_VSX are >>> both set in the status word returned from >>> >>> hwcap = getauxval(AT_HWCAP); >>> >>> This logic is in >>> https://git.lysator.liu.se/nettle/nettle/-/blob/master/fat-ppc.c#L151 >>> and used to selct chacha code here: >>> https://git.lysator.liu.se/nettle/nettle/-/blob/master/fat-ppc.c#L232 >>> >>> > lscpu(1) output: >>> > >>> > Architecture: ppc64 >>> > CPU op-mode(s): 32-bit, 64-bit >>> > Byte Order: Big Endian >>> > CPU(s): 4 >>> > On-line CPU(s) list: 0-3 >>> > Model name: POWER7 (architected), altivec supported >>> >>> Would you expect to have the "vsx" feature mentioned there or not? >>> >>> You can get some diagnostics from the initialization process by setting >>> the NETTLE_FAT_VERBOSE environment variable, and override the automatic >>> detection with the NETTLE_FAT_OVERRIDE environment variable. >>> >>> Can you check what getauxval(AT_HWCAP) returns on your system? >>> >>> I'm not so familiar with powerpc variants. Cc:ing Maamoun who's more >>> familiar with this arch. >>> >>> > Model: 2.3 (pvr 003f 0203) >>> > Thread(s) per core: 4 >>> > Core(s) per socket: 1 >>> > Socket(s): 1 >>> > Virtualization features: >>> > Hypervisor vendor: pHyp >>> > Virtualization type: para >>> >>> Is the program that crashes running under a vm, or is the kernel running >>> on the bare metal? Each layer of vm tends to be ian opportunity to >>> introduce >>> errors in the list of available processor features. >>> >>> > Caches (sum of all): >>> > L1d: 32 KiB (1 instance) >>> > L1i: 32 KiB (1 instance) >>> > L2: 256 KiB (1 instance) >>> > L3: 4 MiB (1 instance) >>> > NUMA: >>> > NUMA node(s): 2 >>> > NUMA node0 CPU(s): >>> > NUMA node1 CPU(s): 0-3 >>> > >>> > >>> > -- System Information: >>> > Debian Release: bookworm/sid >>> > APT prefers unstable >>> > APT policy: (500, 'unstable') >>> > merged-usr: no >>> > Architecture: ppc64 >>> > Foreign Architectures: powerpc >>> > >>> > Kernel: Linux 4.1.42-rivoreo-powerpc64-largepage (SMP w/4 CPU threads) >>> > Locale: LANG=zh_TW.UTF-8, LC_CTYPE=zh_TW.UTF-8 (charmap=UTF-8), >>> LANGUAGE=zh_TW:zh_CN:zh:en_GB:en >>> > Shell: /bin/sh linked to /bin/dash >>> > Init: systemd (via /run/systemd/system) >>> > >>> > Versions of packages libnettle8 depends on: >>> > ii libc6 2.35-3 >>> > >>> > libnettle8 recommends no packages. >>> > >>> > libnettle8 suggests no packages. >>> > >>> > -- no debconf information >>> > >>> >>> Regards, >>> /Niels >>> >>> -- >>> Niels Möller. PGP key CB4962D070D77D7FCB8BA36271D8F1FF368C6677. >>> Internet email is subject to wholesale government surveillance. >>> >> >
