[Bug 256903] arm64: ELF auxiliary vectors for armv7 processors miss VFP information
Date: Wed, 30 Jun 2021 12:19:48 UTC
https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=256903 Bug ID: 256903 Summary: arm64: ELF auxiliary vectors for armv7 processors miss VFP information Product: Base System Version: 13.0-RELEASE Hardware: Any OS: Any Status: New Severity: Affects Only Me Priority: --- Component: arm Assignee: freebsd-arm@FreeBSD.org Reporter: fuz@fuz.su While trying to run armv7 Go programs in a native armv7 jail on arm64 FreeBSD 13.0-RELEASE, I noticed that they refuse to run: $ /usr/local/bin/go runtime: this CPU has no floating point hardware, so it cannot run this GOARM=7 binary. Recompile using GOARM=5. This error message is produced by src/runtime/os_freebsd_arm.go in the Go toolchain: if goarm > 5 && cpu.HWCap&_HWCAP_VFP == 0 { print("runtime: this CPU has no floating point hardware, so it cannot run\n") print("this GOARM=", goarm, " binary. Recompile using GOARM=5.\n") exit(1) } and cpu.HWCap is set from the _AT_HWCAP ELF auxillary vector: func archauxv(tag, val uintptr) { switch tag { case _AT_HWCAP: cpu.HWCap = uint(val) case _AT_HWCAP2: cpu.HWCap2 = uint(val) } } Checking these vectors with a simple test program shows that they are missing: #include <sys/auxv.h> #include <stdio.h> int main() { unsigned long hwcap, hwcap2; if (elf_aux_info(AT_HWCAP, &hwcap, sizeof hwcap) != 0) { perror("elf_aux_info(AT_HWCAP)"); } if (elf_aux_info(AT_HWCAP2, &hwcap2, sizeof hwcap2) != 0) { perror("elf_aux_info(AT_HWCAP2)"); } printf("0x%08lx 0x%08lx\n", hwcap, hwcap2); } On an ARMv7 machine, this prints 0x001fb8d6 0x00000000 as expected. However, in a native armv7 jail on an arm64 machine, we instead get elf_aux_info(AT_HWCAP): No such file or directory elf_aux_info(AT_HWCAP2): No such file or directory 0x00000000 0x00000000 showing that the auxillary vectors are missing. Please make sure these auxillary vectors are present when running armv7 binaries on arm64 FreeBSD. -- You are receiving this mail because: You are the assignee for the bug.