diff options
Diffstat (limited to 'arch/arm64/kernel/mte.c')
| -rw-r--r-- | arch/arm64/kernel/mte.c | 36 |
1 files changed, 35 insertions, 1 deletions
diff --git a/arch/arm64/kernel/mte.c b/arch/arm64/kernel/mte.c index f418ebc65f95..78b3e0f8e997 100644 --- a/arch/arm64/kernel/mte.c +++ b/arch/arm64/kernel/mte.c @@ -186,6 +186,11 @@ void mte_check_tfsr_el1(void) } #endif +/* + * This is where we actually resolve the system and process MTE mode + * configuration into an actual value in SCTLR_EL1 that affects + * userspace. + */ static void mte_update_sctlr_user(struct task_struct *task) { /* @@ -199,9 +204,20 @@ static void mte_update_sctlr_user(struct task_struct *task) unsigned long pref, resolved_mte_tcf; pref = __this_cpu_read(mte_tcf_preferred); + /* + * If there is no overlap between the system preferred and + * program requested values go with what was requested. + */ resolved_mte_tcf = (mte_ctrl & pref) ? pref : mte_ctrl; sctlr &= ~SCTLR_EL1_TCF0_MASK; - if (resolved_mte_tcf & MTE_CTRL_TCF_ASYNC) + /* + * Pick an actual setting. The order in which we check for + * set bits and map into register values determines our + * default order. + */ + if (resolved_mte_tcf & MTE_CTRL_TCF_ASYMM) + sctlr |= SCTLR_EL1_TCF0_ASYMM; + else if (resolved_mte_tcf & MTE_CTRL_TCF_ASYNC) sctlr |= SCTLR_EL1_TCF0_ASYNC; else if (resolved_mte_tcf & MTE_CTRL_TCF_SYNC) sctlr |= SCTLR_EL1_TCF0_SYNC; @@ -253,6 +269,9 @@ void mte_thread_switch(struct task_struct *next) mte_update_sctlr_user(next); mte_update_gcr_excl(next); + /* TCO may not have been disabled on exception entry for the current task. */ + mte_disable_tco_entry(next); + /* * Check if an async tag exception occurred at EL1. * @@ -293,6 +312,17 @@ long set_mte_ctrl(struct task_struct *task, unsigned long arg) if (arg & PR_MTE_TCF_SYNC) mte_ctrl |= MTE_CTRL_TCF_SYNC; + /* + * If the system supports it and both sync and async modes are + * specified then implicitly enable asymmetric mode. + * Userspace could see a mix of both sync and async anyway due + * to differing or changing defaults on CPUs. + */ + if (cpus_have_cap(ARM64_MTE_ASYMM) && + (arg & PR_MTE_TCF_ASYNC) && + (arg & PR_MTE_TCF_SYNC)) + mte_ctrl |= MTE_CTRL_TCF_ASYMM; + task->thread.mte_ctrl = mte_ctrl; if (task == current) { preempt_disable(); @@ -467,6 +497,8 @@ static ssize_t mte_tcf_preferred_show(struct device *dev, return sysfs_emit(buf, "async\n"); case MTE_CTRL_TCF_SYNC: return sysfs_emit(buf, "sync\n"); + case MTE_CTRL_TCF_ASYMM: + return sysfs_emit(buf, "asymm\n"); default: return sysfs_emit(buf, "???\n"); } @@ -482,6 +514,8 @@ static ssize_t mte_tcf_preferred_store(struct device *dev, tcf = MTE_CTRL_TCF_ASYNC; else if (sysfs_streq(buf, "sync")) tcf = MTE_CTRL_TCF_SYNC; + else if (cpus_have_cap(ARM64_MTE_ASYMM) && sysfs_streq(buf, "asymm")) + tcf = MTE_CTRL_TCF_ASYMM; else return -EINVAL; |