As earlier reported here ( https://sourceware.org/pipermail/gdb-patches/2024-February/206644.html ): ... $ gcc hello.c $ gdb -q -batch a.out -ex start -ex 'p $tpidruro' Temporary breakpoint 1 at 0x512 Temporary breakpoint 1, 0xaaaaa512 in main () $1 = <unavailable> ... This is on a pinebook, with 64-bit kernel and 32-bit userland.
As mentioned here ( https://sourceware.org/pipermail/gdb-patches/2024-February/206847.html ), Thiago is working on a patch.
Thank you for opening this bug. I posted the patch here: https://inbox.sourceware.org/gdb-patches/20240227214851.350579-1-thiago.bauermann@linaro.org/
The master branch has been updated by Thiago Bauermann <bauermann@sourceware.org>: https://sourceware.org/git/gitweb.cgi?p=binutils-gdb.git;h=bbb12eb9c84aa2b32480b7c022c494c2469ef717 commit bbb12eb9c84aa2b32480b7c022c494c2469ef717 Author: Thiago Jung Bauermann <thiago.bauermann@linaro.org> Date: Mon Feb 26 19:11:45 2024 -0300 gdb/arm: Remove tpidruro register from non-FreeBSD target descriptions Commit 92d48a1e4eac ("Add an arm-tls feature which includes the tpidruro register from CP15.") introduced the org.gnu.gdb.arm.tls feature, which adds the tpidruro register, and unconditionally enabled it in aarch32_create_target_description. In Linux, the tpidruro register isn't available via ptrace in the 32-bit kernel but it is available for an aarch32 program running under an arm64 kernel via the ptrace compat interface. This isn't currently implemented however, which causes GDB on arm-linux with 64-bit kernel to list the register but show it as unavailable, as reported by Tom de Vries: $ gdb -q -batch a.out -ex start -ex 'p $tpidruro' Temporary breakpoint 1 at 0x512 Temporary breakpoint 1, 0xaaaaa512 in main () $1 = <unavailable> Simon Marchi then clarified: > The only time we should be seeing some "unavailable" registers or memory > is in the context of tracepoints, for things that are not collected. > Seeing an unavailable register here is a sign that something is not > right. Therefore, disable the TLS feature in aarch32 target descriptions for Linux and NetBSD targets (the latter also doesn't seem to support accessing tpidruro either, based on a quick look at arm-netbsd-nat.c). This patch fixes the following tests: Running gdb.base/inline-frame-cycle-unwind.exp ... FAIL: gdb.base/inline-frame-cycle-unwind.exp: cycle at level 3: backtrace when the unwind is broken at frame 3 FAIL: gdb.base/inline-frame-cycle-unwind.exp: cycle at level 5: backtrace when the unwind is broken at frame 5 FAIL: gdb.base/inline-frame-cycle-unwind.exp: cycle at level 1: backtrace when the unwind is broken at frame 1 Tested with Ubuntu 22.04.3 on armv8l-linux-gnueabihf in native, native-gdbserver and native-extended-gdbserver targets with no regressions. PR tdep/31418 Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=31418 Approved-By: John Baldwin <jhb@FreeBSD.org>
Fixed.