Hi Mark,
On Tue, Oct 01, 2024 at 11:58:50PM +0100, Mark Brown wrote:
There is a control HCRX_EL2.GCSEn which must be set to allow GCS features to take effect at lower ELs and also fine grained traps for GCS usage at EL0 and EL1. Configure all these to allow GCS usage by EL0 and EL1.
We also initialise GCSCR_EL1 and GCSCRE0_EL1 to ensure that we can execute function call instructions without faulting regardless of the state when the kernel is started.
Reviewed-by: Thiago Jung Bauermann thiago.bauermann@linaro.org Reviewed-by: Catalin Marinas catalin.marinas@arm.com Signed-off-by: Mark Brown broonie@kernel.org
I just bisected a build failure from a failed linker script assertion that I see with allmodconfig to this change in -next as commit ff5181d8a2a8 ("arm64/gcs: Provide basic EL2 setup to allow GCS usage at EL0 and EL1"):
$ make -skj"$(nproc)" ARCH=arm64 CROSS_COMPILE=aarch64-linux- mrproper allmodconfig vmlinux aarch64-linux-ld: HYP init code too big make[4]: *** [scripts/Makefile.vmlinux:34: vmlinux] Error 1 ...
I see this with both GCC 14 and clang 19, in case toolchain version matters. Bisect log included as well.
Cheers, Nathan
# bad: [b6270c3bca987530eafc6a15f9d54ecd0033e0e3] Add linux-next specific files for 20241009 # good: [75b607fab38d149f232f01eae5e6392b394dd659] Merge tag 'sched_ext-for-6.12-rc2-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/sched_ext git bisect start 'b6270c3bca987530eafc6a15f9d54ecd0033e0e3' '75b607fab38d149f232f01eae5e6392b394dd659' # bad: [76d36603db22f0f0774c19147b25f5a0bcac64e6] Merge branch 'master' of git://git.kernel.org/pub/scm/linux/kernel/git/herbert/cryptodev-2.6.git git bisect bad 76d36603db22f0f0774c19147b25f5a0bcac64e6 # bad: [e90a3e76b4b8080f633a167179f3a76b93077270] Merge branch 'renesas-clk' of git://git.kernel.org/pub/scm/linux/kernel/git/geert/renesas-drivers.git git bisect bad e90a3e76b4b8080f633a167179f3a76b93077270 # good: [dd60a5d8b8ac2e7dc6810182a6dbc251a746f09e] Merge branch 'perf-tools-next' of git://git.kernel.org/pub/scm/linux/kernel/git/perf/perf-tools-next.git git bisect good dd60a5d8b8ac2e7dc6810182a6dbc251a746f09e # bad: [fa74fd4773673726bfa8f89d15805d8a1b26f855] Merge branch 'for-next' of git://git.kernel.org/pub/scm/linux/kernel/git/khilman/linux-omap.git git bisect bad fa74fd4773673726bfa8f89d15805d8a1b26f855 # bad: [a7833d5793f83512f1fb6f36fa7588ea03da6b1b] Merge branch 'for-next' of git://git.kernel.org/pub/scm/linux/kernel/git/amlogic/linux.git git bisect bad a7833d5793f83512f1fb6f36fa7588ea03da6b1b # bad: [c9c0de66c9b5f295f09a116f15401465bdd13263] Merge branch 'for-next/core' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux git bisect bad c9c0de66c9b5f295f09a116f15401465bdd13263 # bad: [506496bcbb4204c9ff5cfe82b1b90e1f14366992] arm64/gcs: Ensure that new threads have a GCS git bisect bad 506496bcbb4204c9ff5cfe82b1b90e1f14366992 # good: [d0aa2b4351862cc2ce8d97e00c96bffc02ea16af] arm64/gcs: Provide put_user_gcs() git bisect good d0aa2b4351862cc2ce8d97e00c96bffc02ea16af # bad: [6497b66ba6945f142902c7e8fce86e47016ead1c] arm64/mm: Map pages for guarded control stack git bisect bad 6497b66ba6945f142902c7e8fce86e47016ead1c # bad: [6487c963083c24ede289d4267ffa60a9db668cd4] arm64/cpufeature: Runtime detection of Guarded Control Stack (GCS) git bisect bad 6487c963083c24ede289d4267ffa60a9db668cd4 # bad: [ff5181d8a2a82c982276a7e035896185c390e856] arm64/gcs: Provide basic EL2 setup to allow GCS usage at EL0 and EL1 git bisect bad ff5181d8a2a82c982276a7e035896185c390e856 # first bad commit: [ff5181d8a2a82c982276a7e035896185c390e856] arm64/gcs: Provide basic EL2 setup to allow GCS usage at EL0 and EL1