diff options
Diffstat (limited to 'arch/arm64/kernel/process.c')
| -rw-r--r-- | arch/arm64/kernel/process.c | 107 |
1 files changed, 81 insertions, 26 deletions
diff --git a/arch/arm64/kernel/process.c b/arch/arm64/kernel/process.c index 84ec630b8ab5..4784011cecac 100644 --- a/arch/arm64/kernel/process.c +++ b/arch/arm64/kernel/process.c @@ -21,6 +21,7 @@ #include <linux/lockdep.h> #include <linux/mman.h> #include <linux/mm.h> +#include <linux/nospec.h> #include <linux/stddef.h> #include <linux/sysctl.h> #include <linux/unistd.h> @@ -52,6 +53,7 @@ #include <asm/exec.h> #include <asm/fpsimd.h> #include <asm/mmu_context.h> +#include <asm/mte.h> #include <asm/processor.h> #include <asm/pointer_auth.h> #include <asm/stacktrace.h> @@ -123,10 +125,8 @@ void arch_cpu_idle(void) * This should do all the clock switching and wait for interrupt * tricks */ - trace_cpu_idle_rcuidle(1, smp_processor_id()); cpu_do_idle(); local_irq_enable(); - trace_cpu_idle_rcuidle(PWR_EVENT_EXIT, smp_processor_id()); } #ifdef CONFIG_HOTPLUG_CPU @@ -241,7 +241,7 @@ static void print_pstate(struct pt_regs *regs) const char *btype_str = btypes[(pstate & PSR_BTYPE_MASK) >> PSR_BTYPE_SHIFT]; - printk("pstate: %08llx (%c%c%c%c %c%c%c%c %cPAN %cUAO BTYPE=%s)\n", + printk("pstate: %08llx (%c%c%c%c %c%c%c%c %cPAN %cUAO %cTCO BTYPE=%s)\n", pstate, pstate & PSR_N_BIT ? 'N' : 'n', pstate & PSR_Z_BIT ? 'Z' : 'z', @@ -253,6 +253,7 @@ static void print_pstate(struct pt_regs *regs) pstate & PSR_F_BIT ? 'F' : 'f', pstate & PSR_PAN_BIT ? '+' : '-', pstate & PSR_UAO_BIT ? '+' : '-', + pstate & PSR_TCO_BIT ? '+' : '-', btype_str); } } @@ -338,6 +339,7 @@ void flush_thread(void) tls_thread_flush(); flush_ptrace_hw_breakpoint(current); flush_tagged_addr_state(); + flush_mte_state(); } void release_thread(struct task_struct *dead_task) @@ -370,6 +372,9 @@ int arch_dup_task_struct(struct task_struct *dst, struct task_struct *src) dst->thread.sve_state = NULL; clear_tsk_thread_flag(dst, TIF_SVE); + /* clear any pending asynchronous tag fault raised by the parent */ + clear_tsk_thread_flag(dst, TIF_MTE_ASYNC_FAULT); + return 0; } @@ -423,8 +428,7 @@ int copy_thread(unsigned long clone_flags, unsigned long stack_start, cpus_have_const_cap(ARM64_HAS_UAO)) childregs->pstate |= PSR_UAO_BIT; - if (arm64_get_ssbd_state() == ARM64_SSBD_FORCE_DISABLE) - set_ssbs_bit(childregs); + spectre_v4_enable_task_mitigation(p); if (system_uses_irq_prio_masking()) childregs->pmr_save = GIC_PRIO_IRQON; @@ -474,8 +478,6 @@ void uao_thread_switch(struct task_struct *next) */ static void ssbs_thread_switch(struct task_struct *next) { - struct pt_regs *regs = task_pt_regs(next); - /* * Nothing to do for kernel threads, but 'regs' may be junk * (e.g. idle task) so check the flags and bail early. @@ -487,18 +489,10 @@ static void ssbs_thread_switch(struct task_struct *next) * If all CPUs implement the SSBS extension, then we just need to * context-switch the PSTATE field. */ - if (cpu_have_feature(cpu_feature(SSBS))) + if (cpus_have_const_cap(ARM64_SSBS)) return; - /* If the mitigation is enabled, then we leave SSBS clear. */ - if ((arm64_get_ssbd_state() == ARM64_SSBD_FORCE_ENABLE) || - test_tsk_thread_flag(next, TIF_SSBD)) - return; - - if (compat_user_mode(regs)) - set_compat_ssbs_bit(regs); - else if (user_mode(regs)) - set_ssbs_bit(regs); + spectre_v4_enable_task_mitigation(next); } /* @@ -516,6 +510,39 @@ 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 + */ +static void erratum_1418040_thread_switch(struct task_struct *prev, + struct task_struct *next) +{ + bool prev32, next32; + u64 val; + + if (!(IS_ENABLED(CONFIG_ARM64_ERRATUM_1418040) && + cpus_have_const_cap(ARM64_WORKAROUND_1418040))) + return; + + prev32 = is_compat_thread(task_thread_info(prev)); + next32 = is_compat_thread(task_thread_info(next)); + + if (prev32 == next32) + return; + + val = read_sysreg(cntkctl_el1); + + if (!next32) + val |= ARCH_TIMER_USR_VCT_ACCESS_EN; + else + val &= ~ARCH_TIMER_USR_VCT_ACCESS_EN; + + write_sysreg(val, cntkctl_el1); +} + +/* * Thread switching. */ __notrace_funcgraph struct task_struct *__switch_to(struct task_struct *prev, @@ -530,6 +557,7 @@ __notrace_funcgraph struct task_struct *__switch_to(struct task_struct *prev, entry_task_switch(next); uao_thread_switch(next); ssbs_thread_switch(next); + erratum_1418040_thread_switch(prev, next); /* * Complete any pending TLB or cache maintenance on this CPU in case @@ -539,6 +567,13 @@ __notrace_funcgraph struct task_struct *__switch_to(struct task_struct *prev, */ dsb(ish); + /* + * MTE thread switching must happen after the DSB above to ensure that + * any asynchronous tag check faults have been logged in the TFSR*_EL1 + * registers. + */ + mte_thread_switch(next); + /* the actual thread switch */ last = cpu_switch_to(prev, next); @@ -588,6 +623,11 @@ void arch_setup_new_exec(void) current->mm->context.flags = is_compat_task() ? MMCF_AARCH32 : 0; ptrauth_thread_init_user(current); + + if (task_spec_ssb_noexec(current)) { + arch_prctl_spec_ctrl_set(current, PR_SPEC_STORE_BYPASS, + PR_SPEC_ENABLE); + } } #ifdef CONFIG_ARM64_TAGGED_ADDR_ABI @@ -596,11 +636,18 @@ void arch_setup_new_exec(void) */ static unsigned int tagged_addr_disabled; -long set_tagged_addr_ctrl(unsigned long arg) +long set_tagged_addr_ctrl(struct task_struct *task, unsigned long arg) { - if (is_compat_task()) + unsigned long valid_mask = PR_TAGGED_ADDR_ENABLE; + struct thread_info *ti = task_thread_info(task); + + if (is_compat_thread(ti)) return -EINVAL; - if (arg & ~PR_TAGGED_ADDR_ENABLE) + + if (system_supports_mte()) + valid_mask |= PR_MTE_TCF_MASK | PR_MTE_TAG_MASK; + + if (arg & ~valid_mask) return -EINVAL; /* @@ -610,20 +657,28 @@ long set_tagged_addr_ctrl(unsigned long arg) if (arg & PR_TAGGED_ADDR_ENABLE && tagged_addr_disabled) return -EINVAL; - update_thread_flag(TIF_TAGGED_ADDR, arg & PR_TAGGED_ADDR_ENABLE); + if (set_mte_ctrl(task, arg) != 0) + return -EINVAL; + + update_ti_thread_flag(ti, TIF_TAGGED_ADDR, arg & PR_TAGGED_ADDR_ENABLE); return 0; } -long get_tagged_addr_ctrl(void) +long get_tagged_addr_ctrl(struct task_struct *task) { - if (is_compat_task()) + long ret = 0; + struct thread_info *ti = task_thread_info(task); + + if (is_compat_thread(ti)) return -EINVAL; - if (test_thread_flag(TIF_TAGGED_ADDR)) - return PR_TAGGED_ADDR_ENABLE; + if (test_ti_thread_flag(ti, TIF_TAGGED_ADDR)) + ret = PR_TAGGED_ADDR_ENABLE; - return 0; + ret |= get_mte_ctrl(task); + + return ret; } /* |