diff --git a/arch/arm64/kernel/process.c b/arch/arm64/kernel/process.c index d7c90d8e25d149c565f03ecaae65525a1a296d27..7317c79db9e8ba2f2302894a34ba4b25887474a9 100644 --- a/arch/arm64/kernel/process.c +++ b/arch/arm64/kernel/process.c @@ -506,34 +506,26 @@ static void entry_task_switch(struct task_struct *next) /* * ARM erratum 1418040 handling, affecting the 32bit view of CNTVCT. - * Assuming the virtual counter is enabled at the beginning of times: - * - * - disable access when switching from a 64bit task to a 32bit task - * - enable access when switching from a 32bit task to a 64bit task + * Ensure access is disabled when switching to a 32bit task, ensure + * access is enabled when switching to a 64bit task. */ -static void erratum_1418040_thread_switch(struct task_struct *prev, - struct task_struct *next) +static void erratum_1418040_thread_switch(struct task_struct *next) { - bool prev32, next32; - u64 val; - - if (!IS_ENABLED(CONFIG_ARM64_ERRATUM_1418040)) - return; - - prev32 = is_a32_compat_thread(task_thread_info(prev)); - next32 = is_a32_compat_thread(task_thread_info(next)); - - if (prev32 == next32 || !this_cpu_has_cap(ARM64_WORKAROUND_1418040)) + if (!IS_ENABLED(CONFIG_ARM64_ERRATUM_1418040) || + !this_cpu_has_cap(ARM64_WORKAROUND_1418040)) return; - val = read_sysreg(cntkctl_el1); - - if (!next32) - val |= ARCH_TIMER_USR_VCT_ACCESS_EN; + if (is_a32_compat_thread(task_thread_info(next))) + sysreg_clear_set(cntkctl_el1, ARCH_TIMER_USR_VCT_ACCESS_EN, 0); else - val &= ~ARCH_TIMER_USR_VCT_ACCESS_EN; + sysreg_clear_set(cntkctl_el1, 0, ARCH_TIMER_USR_VCT_ACCESS_EN); +} - write_sysreg(val, cntkctl_el1); +static void erratum_1418040_new_exec(void) +{ + preempt_disable(); + erratum_1418040_thread_switch(current); + preempt_enable(); } /* @@ -550,7 +542,7 @@ __notrace_funcgraph struct task_struct *__switch_to(struct task_struct *prev, contextidr_thread_switch(next); entry_task_switch(next); ssbs_thread_switch(next); - erratum_1418040_thread_switch(prev, next); + erratum_1418040_thread_switch(next); /* * Complete any pending TLB or cache maintenance on this CPU in case @@ -618,6 +610,7 @@ void arch_setup_new_exec(void) current->mm->context.flags = is_compat_task() ? MMCF_AARCH32 : 0; ptrauth_thread_init_user(current); + erratum_1418040_new_exec(); if (task_spec_ssb_noexec(current)) { arch_prctl_spec_ctrl_set(current, PR_SPEC_STORE_BYPASS,