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| author | Szabolcs Nagy <szabolcs.nagy@arm.com> | 2023-07-17 08:31:05 +0100 |
|---|---|---|
| committer | Szabolcs Nagy <szabolcs.nagy@arm.com> | 2024-02-02 15:58:11 +0000 |
| commit | 200010339f4fa0449a7bd76555931881eaea916c (patch) | |
| tree | 838c67f8ca1093e3b26c6a1c392ac5b6a83d28ad /sysdeps/unix/sysv/linux/aarch64/cpu-features.c | |
| parent | 56253d5f47330f502dd6bc8f3e12eeabf6c20a8b (diff) | |
| download | glibc-200010339f4fa0449a7bd76555931881eaea916c.tar.gz glibc-200010339f4fa0449a7bd76555931881eaea916c.tar.xz glibc-200010339f4fa0449a7bd76555931881eaea916c.zip | |
aarch64: Add glibc.cpu.aarch64_gcs tunable
This tunable is for controlling the GCS status. It is the argument to the PR_SET_SHADOW_STACK_STATUS prctl, by default 0, so GCS is disabled. The status is stored into GL(dl_aarch64_gcs) early and only applied later, since enabling GCS is tricky: it must happen on a top level stack frame. (Using GL instead of GLRO because it may need updates depending on loaded libraries that happen after readonly protection is applied, however library marking based GCS setting is not yet implemented.)
Diffstat (limited to 'sysdeps/unix/sysv/linux/aarch64/cpu-features.c')
| -rw-r--r-- | sysdeps/unix/sysv/linux/aarch64/cpu-features.c | 4 |
1 files changed, 4 insertions, 0 deletions
diff --git a/sysdeps/unix/sysv/linux/aarch64/cpu-features.c b/sysdeps/unix/sysv/linux/aarch64/cpu-features.c index b1a3f673f0..a8b6a4654a 100644 --- a/sysdeps/unix/sysv/linux/aarch64/cpu-features.c +++ b/sysdeps/unix/sysv/linux/aarch64/cpu-features.c @@ -128,4 +128,8 @@ init_cpu_features (struct cpu_features *cpu_features) /* Check if MOPS is supported. */ cpu_features->mops = GLRO (dl_hwcap2) & HWCAP2_MOPS; + + if (GLRO (dl_hwcap2) & HWCAP2_GCS) + /* GCS status may be updated later by binary compatibility checks. */ + GL (dl_aarch64_gcs) = TUNABLE_GET (glibc, cpu, aarch64_gcs, uint64_t, 0); } |