diff options
Diffstat (limited to 'arch/powerpc/kernel/security.c')
| -rw-r--r-- | arch/powerpc/kernel/security.c | 37 |
1 files changed, 19 insertions, 18 deletions
diff --git a/arch/powerpc/kernel/security.c b/arch/powerpc/kernel/security.c index 206475e3e0b4..4856e1a5161c 100644 --- a/arch/powerpc/kernel/security.c +++ b/arch/powerpc/kernel/security.c @@ -364,26 +364,27 @@ ssize_t cpu_show_spec_store_bypass(struct device *dev, struct device_attribute * static int ssb_prctl_get(struct task_struct *task) { + /* + * The STF_BARRIER feature is on by default, so if it's off that means + * firmware has explicitly said the CPU is not vulnerable via either + * the hypercall or device tree. + */ + if (!security_ftr_enabled(SEC_FTR_STF_BARRIER)) + return PR_SPEC_NOT_AFFECTED; + + /* + * If the system's CPU has no known barrier (see setup_stf_barrier()) + * then assume that the CPU is not vulnerable. + */ if (stf_enabled_flush_types == STF_BARRIER_NONE) - /* - * We don't have an explicit signal from firmware that we're - * vulnerable or not, we only have certain CPU revisions that - * are known to be vulnerable. - * - * We assume that if we're on another CPU, where the barrier is - * NONE, then we are not vulnerable. - */ return PR_SPEC_NOT_AFFECTED; - else - /* - * If we do have a barrier type then we are vulnerable. The - * barrier is not a global or per-process mitigation, so the - * only value we can report here is PR_SPEC_ENABLE, which - * appears as "vulnerable" in /proc. - */ - return PR_SPEC_ENABLE; - - return -EINVAL; + + /* + * Otherwise the CPU is vulnerable. The barrier is not a global or + * per-process mitigation, so the only value that can be reported here + * is PR_SPEC_ENABLE, which appears as "vulnerable" in /proc. + */ + return PR_SPEC_ENABLE; } int arch_prctl_spec_ctrl_get(struct task_struct *task, unsigned long which) |