| // SPDX-License-Identifier: GPL-2.0-only |
| /* |
| * Based on arch/arm/kernel/process.c |
| * |
| * Original Copyright (C) 1995 Linus Torvalds |
| * Copyright (C) 1996-2000 Russell King - Converted to ARM. |
| * Copyright (C) 2012 ARM Ltd. |
| */ |
| #include <linux/compat.h> |
| #include <linux/efi.h> |
| #include <linux/elf.h> |
| #include <linux/export.h> |
| #include <linux/sched.h> |
| #include <linux/sched/debug.h> |
| #include <linux/sched/task.h> |
| #include <linux/sched/task_stack.h> |
| #include <linux/kernel.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> |
| #include <linux/user.h> |
| #include <linux/delay.h> |
| #include <linux/reboot.h> |
| #include <linux/interrupt.h> |
| #include <linux/init.h> |
| #include <linux/cpu.h> |
| #include <linux/elfcore.h> |
| #include <linux/pm.h> |
| #include <linux/tick.h> |
| #include <linux/utsname.h> |
| #include <linux/uaccess.h> |
| #include <linux/random.h> |
| #include <linux/hw_breakpoint.h> |
| #include <linux/personality.h> |
| #include <linux/notifier.h> |
| #include <trace/events/power.h> |
| #include <linux/percpu.h> |
| #include <linux/thread_info.h> |
| #include <linux/prctl.h> |
| #include <linux/stacktrace.h> |
| |
| #include <asm/alternative.h> |
| #include <asm/compat.h> |
| #include <asm/cpufeature.h> |
| #include <asm/cacheflush.h> |
| #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> |
| #include <asm/switch_to.h> |
| #include <asm/system_misc.h> |
| |
| #if defined(CONFIG_STACKPROTECTOR) && !defined(CONFIG_STACKPROTECTOR_PER_TASK) |
| #include <linux/stackprotector.h> |
| unsigned long __stack_chk_guard __ro_after_init; |
| EXPORT_SYMBOL(__stack_chk_guard); |
| #endif |
| |
| /* |
| * Function pointers to optional machine specific functions |
| */ |
| void (*pm_power_off)(void); |
| EXPORT_SYMBOL_GPL(pm_power_off); |
| |
| #ifdef CONFIG_HOTPLUG_CPU |
| void arch_cpu_idle_dead(void) |
| { |
| cpu_die(); |
| } |
| #endif |
| |
| /* |
| * Called by kexec, immediately prior to machine_kexec(). |
| * |
| * This must completely disable all secondary CPUs; simply causing those CPUs |
| * to execute e.g. a RAM-based pin loop is not sufficient. This allows the |
| * kexec'd kernel to use any and all RAM as it sees fit, without having to |
| * avoid any code or data used by any SW CPU pin loop. The CPU hotplug |
| * functionality embodied in smpt_shutdown_nonboot_cpus() to achieve this. |
| */ |
| void machine_shutdown(void) |
| { |
| smp_shutdown_nonboot_cpus(reboot_cpu); |
| } |
| |
| /* |
| * Halting simply requires that the secondary CPUs stop performing any |
| * activity (executing tasks, handling interrupts). smp_send_stop() |
| * achieves this. |
| */ |
| void machine_halt(void) |
| { |
| local_irq_disable(); |
| smp_send_stop(); |
| while (1); |
| } |
| |
| /* |
| * Power-off simply requires that the secondary CPUs stop performing any |
| * activity (executing tasks, handling interrupts). smp_send_stop() |
| * achieves this. When the system power is turned off, it will take all CPUs |
| * with it. |
| */ |
| void machine_power_off(void) |
| { |
| local_irq_disable(); |
| smp_send_stop(); |
| do_kernel_power_off(); |
| } |
| |
| /* |
| * Restart requires that the secondary CPUs stop performing any activity |
| * while the primary CPU resets the system. Systems with multiple CPUs must |
| * provide a HW restart implementation, to ensure that all CPUs reset at once. |
| * This is required so that any code running after reset on the primary CPU |
| * doesn't have to co-ordinate with other CPUs to ensure they aren't still |
| * executing pre-reset code, and using RAM that the primary CPU's code wishes |
| * to use. Implementing such co-ordination would be essentially impossible. |
| */ |
| void machine_restart(char *cmd) |
| { |
| /* Disable interrupts first */ |
| local_irq_disable(); |
| smp_send_stop(); |
| |
| /* |
| * UpdateCapsule() depends on the system being reset via |
| * ResetSystem(). |
| */ |
| if (efi_enabled(EFI_RUNTIME_SERVICES)) |
| efi_reboot(reboot_mode, NULL); |
| |
| /* Now call the architecture specific reboot code. */ |
| do_kernel_restart(cmd); |
| |
| /* |
| * Whoops - the architecture was unable to reboot. |
| */ |
| printk("Reboot failed -- System halted\n"); |
| while (1); |
| } |
| |
| #define bstr(suffix, str) [PSR_BTYPE_ ## suffix >> PSR_BTYPE_SHIFT] = str |
| static const char *const btypes[] = { |
| bstr(NONE, "--"), |
| bstr( JC, "jc"), |
| bstr( C, "-c"), |
| bstr( J , "j-") |
| }; |
| #undef bstr |
| |
| static void print_pstate(struct pt_regs *regs) |
| { |
| u64 pstate = regs->pstate; |
| |
| if (compat_user_mode(regs)) { |
| printk("pstate: %08llx (%c%c%c%c %c %s %s %c%c%c %cDIT %cSSBS)\n", |
| pstate, |
| pstate & PSR_AA32_N_BIT ? 'N' : 'n', |
| pstate & PSR_AA32_Z_BIT ? 'Z' : 'z', |
| pstate & PSR_AA32_C_BIT ? 'C' : 'c', |
| pstate & PSR_AA32_V_BIT ? 'V' : 'v', |
| pstate & PSR_AA32_Q_BIT ? 'Q' : 'q', |
| pstate & PSR_AA32_T_BIT ? "T32" : "A32", |
| pstate & PSR_AA32_E_BIT ? "BE" : "LE", |
| pstate & PSR_AA32_A_BIT ? 'A' : 'a', |
| pstate & PSR_AA32_I_BIT ? 'I' : 'i', |
| pstate & PSR_AA32_F_BIT ? 'F' : 'f', |
| pstate & PSR_AA32_DIT_BIT ? '+' : '-', |
| pstate & PSR_AA32_SSBS_BIT ? '+' : '-'); |
| } else { |
| 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 %cTCO %cDIT %cSSBS BTYPE=%s)\n", |
| pstate, |
| pstate & PSR_N_BIT ? 'N' : 'n', |
| pstate & PSR_Z_BIT ? 'Z' : 'z', |
| pstate & PSR_C_BIT ? 'C' : 'c', |
| pstate & PSR_V_BIT ? 'V' : 'v', |
| pstate & PSR_D_BIT ? 'D' : 'd', |
| pstate & PSR_A_BIT ? 'A' : 'a', |
| pstate & PSR_I_BIT ? 'I' : 'i', |
| pstate & PSR_F_BIT ? 'F' : 'f', |
| pstate & PSR_PAN_BIT ? '+' : '-', |
| pstate & PSR_UAO_BIT ? '+' : '-', |
| pstate & PSR_TCO_BIT ? '+' : '-', |
| pstate & PSR_DIT_BIT ? '+' : '-', |
| pstate & PSR_SSBS_BIT ? '+' : '-', |
| btype_str); |
| } |
| } |
| |
| void __show_regs(struct pt_regs *regs) |
| { |
| int i, top_reg; |
| u64 lr, sp; |
| |
| if (compat_user_mode(regs)) { |
| lr = regs->compat_lr; |
| sp = regs->compat_sp; |
| top_reg = 12; |
| } else { |
| lr = regs->regs[30]; |
| sp = regs->sp; |
| top_reg = 29; |
| } |
| |
| show_regs_print_info(KERN_DEFAULT); |
| print_pstate(regs); |
| |
| if (!user_mode(regs)) { |
| printk("pc : %pS\n", (void *)regs->pc); |
| printk("lr : %pS\n", (void *)ptrauth_strip_insn_pac(lr)); |
| } else { |
| printk("pc : %016llx\n", regs->pc); |
| printk("lr : %016llx\n", lr); |
| } |
| |
| printk("sp : %016llx\n", sp); |
| |
| if (system_uses_irq_prio_masking()) |
| printk("pmr_save: %08llx\n", regs->pmr_save); |
| |
| i = top_reg; |
| |
| while (i >= 0) { |
| printk("x%-2d: %016llx", i, regs->regs[i]); |
| |
| while (i-- % 3) |
| pr_cont(" x%-2d: %016llx", i, regs->regs[i]); |
| |
| pr_cont("\n"); |
| } |
| } |
| |
| void show_regs(struct pt_regs *regs) |
| { |
| __show_regs(regs); |
| dump_backtrace(regs, NULL, KERN_DEFAULT); |
| } |
| |
| static void tls_thread_flush(void) |
| { |
| write_sysreg(0, tpidr_el0); |
| if (system_supports_tpidr2()) |
| write_sysreg_s(0, SYS_TPIDR2_EL0); |
| |
| if (is_compat_task()) { |
| current->thread.uw.tp_value = 0; |
| |
| /* |
| * We need to ensure ordering between the shadow state and the |
| * hardware state, so that we don't corrupt the hardware state |
| * with a stale shadow state during context switch. |
| */ |
| barrier(); |
| write_sysreg(0, tpidrro_el0); |
| } |
| } |
| |
| static void flush_tagged_addr_state(void) |
| { |
| if (IS_ENABLED(CONFIG_ARM64_TAGGED_ADDR_ABI)) |
| clear_thread_flag(TIF_TAGGED_ADDR); |
| } |
| |
| void flush_thread(void) |
| { |
| fpsimd_flush_thread(); |
| tls_thread_flush(); |
| flush_ptrace_hw_breakpoint(current); |
| flush_tagged_addr_state(); |
| } |
| |
| void release_thread(struct task_struct *dead_task) |
| { |
| } |
| |
| void arch_release_task_struct(struct task_struct *tsk) |
| { |
| fpsimd_release_task(tsk); |
| } |
| |
| int arch_dup_task_struct(struct task_struct *dst, struct task_struct *src) |
| { |
| if (current->mm) |
| fpsimd_preserve_current_state(); |
| *dst = *src; |
| |
| /* We rely on the above assignment to initialize dst's thread_flags: */ |
| BUILD_BUG_ON(!IS_ENABLED(CONFIG_THREAD_INFO_IN_TASK)); |
| |
| /* |
| * Detach src's sve_state (if any) from dst so that it does not |
| * get erroneously used or freed prematurely. dst's copies |
| * will be allocated on demand later on if dst uses SVE. |
| * For consistency, also clear TIF_SVE here: this could be done |
| * later in copy_process(), but to avoid tripping up future |
| * maintainers it is best not to leave TIF flags and buffers in |
| * an inconsistent state, even temporarily. |
| */ |
| dst->thread.sve_state = NULL; |
| clear_tsk_thread_flag(dst, TIF_SVE); |
| |
| /* |
| * In the unlikely event that we create a new thread with ZA |
| * enabled we should retain the ZA state so duplicate it here. |
| * This may be shortly freed if we exec() or if CLONE_SETTLS |
| * but it's simpler to do it here. To avoid confusing the rest |
| * of the code ensure that we have a sve_state allocated |
| * whenever za_state is allocated. |
| */ |
| if (thread_za_enabled(&src->thread)) { |
| dst->thread.sve_state = kzalloc(sve_state_size(src), |
| GFP_KERNEL); |
| if (!dst->thread.sve_state) |
| return -ENOMEM; |
| dst->thread.za_state = kmemdup(src->thread.za_state, |
| za_state_size(src), |
| GFP_KERNEL); |
| if (!dst->thread.za_state) { |
| kfree(dst->thread.sve_state); |
| dst->thread.sve_state = NULL; |
| return -ENOMEM; |
| } |
| } else { |
| dst->thread.za_state = NULL; |
| clear_tsk_thread_flag(dst, TIF_SME); |
| } |
| |
| /* clear any pending asynchronous tag fault raised by the parent */ |
| clear_tsk_thread_flag(dst, TIF_MTE_ASYNC_FAULT); |
| |
| return 0; |
| } |
| |
| asmlinkage void ret_from_fork(void) asm("ret_from_fork"); |
| |
| int copy_thread(struct task_struct *p, const struct kernel_clone_args *args) |
| { |
| unsigned long clone_flags = args->flags; |
| unsigned long stack_start = args->stack; |
| unsigned long tls = args->tls; |
| struct pt_regs *childregs = task_pt_regs(p); |
| |
| memset(&p->thread.cpu_context, 0, sizeof(struct cpu_context)); |
| |
| /* |
| * In case p was allocated the same task_struct pointer as some |
| * other recently-exited task, make sure p is disassociated from |
| * any cpu that may have run that now-exited task recently. |
| * Otherwise we could erroneously skip reloading the FPSIMD |
| * registers for p. |
| */ |
| fpsimd_flush_task_state(p); |
| |
| ptrauth_thread_init_kernel(p); |
| |
| if (likely(!args->fn)) { |
| *childregs = *current_pt_regs(); |
| childregs->regs[0] = 0; |
| |
| /* |
| * Read the current TLS pointer from tpidr_el0 as it may be |
| * out-of-sync with the saved value. |
| */ |
| *task_user_tls(p) = read_sysreg(tpidr_el0); |
| if (system_supports_tpidr2()) |
| p->thread.tpidr2_el0 = read_sysreg_s(SYS_TPIDR2_EL0); |
| |
| if (stack_start) { |
| if (is_compat_thread(task_thread_info(p))) |
| childregs->compat_sp = stack_start; |
| else |
| childregs->sp = stack_start; |
| } |
| |
| /* |
| * If a TLS pointer was passed to clone, use it for the new |
| * thread. We also reset TPIDR2 if it's in use. |
| */ |
| if (clone_flags & CLONE_SETTLS) { |
| p->thread.uw.tp_value = tls; |
| p->thread.tpidr2_el0 = 0; |
| } |
| } else { |
| /* |
| * A kthread has no context to ERET to, so ensure any buggy |
| * ERET is treated as an illegal exception return. |
| * |
| * When a user task is created from a kthread, childregs will |
| * be initialized by start_thread() or start_compat_thread(). |
| */ |
| memset(childregs, 0, sizeof(struct pt_regs)); |
| childregs->pstate = PSR_MODE_EL1h | PSR_IL_BIT; |
| |
| p->thread.cpu_context.x19 = (unsigned long)args->fn; |
| p->thread.cpu_context.x20 = (unsigned long)args->fn_arg; |
| } |
| p->thread.cpu_context.pc = (unsigned long)ret_from_fork; |
| p->thread.cpu_context.sp = (unsigned long)childregs; |
| /* |
| * For the benefit of the unwinder, set up childregs->stackframe |
| * as the final frame for the new task. |
| */ |
| p->thread.cpu_context.fp = (unsigned long)childregs->stackframe; |
| |
| ptrace_hw_copy_thread(p); |
| |
| return 0; |
| } |
| |
| void tls_preserve_current_state(void) |
| { |
| *task_user_tls(current) = read_sysreg(tpidr_el0); |
| if (system_supports_tpidr2() && !is_compat_task()) |
| current->thread.tpidr2_el0 = read_sysreg_s(SYS_TPIDR2_EL0); |
| } |
| |
| static void tls_thread_switch(struct task_struct *next) |
| { |
| tls_preserve_current_state(); |
| |
| if (is_compat_thread(task_thread_info(next))) |
| write_sysreg(next->thread.uw.tp_value, tpidrro_el0); |
| else if (!arm64_kernel_unmapped_at_el0()) |
| write_sysreg(0, tpidrro_el0); |
| |
| write_sysreg(*task_user_tls(next), tpidr_el0); |
| if (system_supports_tpidr2()) |
| write_sysreg_s(next->thread.tpidr2_el0, SYS_TPIDR2_EL0); |
| } |
| |
| /* |
| * Force SSBS state on context-switch, since it may be lost after migrating |
| * from a CPU which treats the bit as RES0 in a heterogeneous system. |
| */ |
| static void ssbs_thread_switch(struct task_struct *next) |
| { |
| /* |
| * Nothing to do for kernel threads, but 'regs' may be junk |
| * (e.g. idle task) so check the flags and bail early. |
| */ |
| if (unlikely(next->flags & PF_KTHREAD)) |
| return; |
| |
| /* |
| * If all CPUs implement the SSBS extension, then we just need to |
| * context-switch the PSTATE field. |
| */ |
| if (cpus_have_const_cap(ARM64_SSBS)) |
| return; |
| |
| spectre_v4_enable_task_mitigation(next); |
| } |
| |
| /* |
| * We store our current task in sp_el0, which is clobbered by userspace. Keep a |
| * shadow copy so that we can restore this upon entry from userspace. |
| * |
| * This is *only* for exception entry from EL0, and is not valid until we |
| * __switch_to() a user task. |
| */ |
| DEFINE_PER_CPU(struct task_struct *, __entry_task); |
| |
| static void entry_task_switch(struct task_struct *next) |
| { |
| __this_cpu_write(__entry_task, next); |
| } |
| |
| /* |
| * ARM erratum 1418040 handling, affecting the 32bit view of CNTVCT. |
| * 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 *next) |
| { |
| if (!IS_ENABLED(CONFIG_ARM64_ERRATUM_1418040) || |
| !this_cpu_has_cap(ARM64_WORKAROUND_1418040)) |
| return; |
| |
| if (is_compat_thread(task_thread_info(next))) |
| sysreg_clear_set(cntkctl_el1, ARCH_TIMER_USR_VCT_ACCESS_EN, 0); |
| else |
| sysreg_clear_set(cntkctl_el1, 0, ARCH_TIMER_USR_VCT_ACCESS_EN); |
| } |
| |
| static void erratum_1418040_new_exec(void) |
| { |
| preempt_disable(); |
| erratum_1418040_thread_switch(current); |
| preempt_enable(); |
| } |
| |
| /* |
| * __switch_to() checks current->thread.sctlr_user as an optimisation. Therefore |
| * this function must be called with preemption disabled and the update to |
| * sctlr_user must be made in the same preemption disabled block so that |
| * __switch_to() does not see the variable update before the SCTLR_EL1 one. |
| */ |
| void update_sctlr_el1(u64 sctlr) |
| { |
| /* |
| * EnIA must not be cleared while in the kernel as this is necessary for |
| * in-kernel PAC. It will be cleared on kernel exit if needed. |
| */ |
| sysreg_clear_set(sctlr_el1, SCTLR_USER_MASK & ~SCTLR_ELx_ENIA, sctlr); |
| |
| /* ISB required for the kernel uaccess routines when setting TCF0. */ |
| isb(); |
| } |
| |
| /* |
| * Thread switching. |
| */ |
| __notrace_funcgraph __sched |
| struct task_struct *__switch_to(struct task_struct *prev, |
| struct task_struct *next) |
| { |
| struct task_struct *last; |
| |
| fpsimd_thread_switch(next); |
| tls_thread_switch(next); |
| hw_breakpoint_thread_switch(next); |
| contextidr_thread_switch(next); |
| entry_task_switch(next); |
| ssbs_thread_switch(next); |
| erratum_1418040_thread_switch(next); |
| ptrauth_thread_switch_user(next); |
| |
| /* |
| * Complete any pending TLB or cache maintenance on this CPU in case |
| * the thread migrates to a different CPU. |
| * This full barrier is also required by the membarrier system |
| * call. |
| */ |
| 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); |
| /* avoid expensive SCTLR_EL1 accesses if no change */ |
| if (prev->thread.sctlr_user != next->thread.sctlr_user) |
| update_sctlr_el1(next->thread.sctlr_user); |
| |
| /* the actual thread switch */ |
| last = cpu_switch_to(prev, next); |
| |
| return last; |
| } |
| |
| struct wchan_info { |
| unsigned long pc; |
| int count; |
| }; |
| |
| static bool get_wchan_cb(void *arg, unsigned long pc) |
| { |
| struct wchan_info *wchan_info = arg; |
| |
| if (!in_sched_functions(pc)) { |
| wchan_info->pc = pc; |
| return false; |
| } |
| return wchan_info->count++ < 16; |
| } |
| |
| unsigned long __get_wchan(struct task_struct *p) |
| { |
| struct wchan_info wchan_info = { |
| .pc = 0, |
| .count = 0, |
| }; |
| |
| if (!try_get_task_stack(p)) |
| return 0; |
| |
| arch_stack_walk(get_wchan_cb, &wchan_info, p, NULL); |
| |
| put_task_stack(p); |
| |
| return wchan_info.pc; |
| } |
| |
| unsigned long arch_align_stack(unsigned long sp) |
| { |
| if (!(current->personality & ADDR_NO_RANDOMIZE) && randomize_va_space) |
| sp -= get_random_int() & ~PAGE_MASK; |
| return sp & ~0xf; |
| } |
| |
| #ifdef CONFIG_COMPAT |
| int compat_elf_check_arch(const struct elf32_hdr *hdr) |
| { |
| if (!system_supports_32bit_el0()) |
| return false; |
| |
| if ((hdr)->e_machine != EM_ARM) |
| return false; |
| |
| if (!((hdr)->e_flags & EF_ARM_EABI_MASK)) |
| return false; |
| |
| /* |
| * Prevent execve() of a 32-bit program from a deadline task |
| * if the restricted affinity mask would be inadmissible on an |
| * asymmetric system. |
| */ |
| return !static_branch_unlikely(&arm64_mismatched_32bit_el0) || |
| !dl_task_check_affinity(current, system_32bit_el0_cpumask()); |
| } |
| #endif |
| |
| /* |
| * Called from setup_new_exec() after (COMPAT_)SET_PERSONALITY. |
| */ |
| void arch_setup_new_exec(void) |
| { |
| unsigned long mmflags = 0; |
| |
| if (is_compat_task()) { |
| mmflags = MMCF_AARCH32; |
| |
| /* |
| * Restrict the CPU affinity mask for a 32-bit task so that |
| * it contains only 32-bit-capable CPUs. |
| * |
| * From the perspective of the task, this looks similar to |
| * what would happen if the 64-bit-only CPUs were hot-unplugged |
| * at the point of execve(), although we try a bit harder to |
| * honour the cpuset hierarchy. |
| */ |
| if (static_branch_unlikely(&arm64_mismatched_32bit_el0)) |
| force_compatible_cpus_allowed_ptr(current); |
| } else if (static_branch_unlikely(&arm64_mismatched_32bit_el0)) { |
| relax_compatible_cpus_allowed_ptr(current); |
| } |
| |
| current->mm->context.flags = mmflags; |
| ptrauth_thread_init_user(); |
| mte_thread_init_user(); |
| erratum_1418040_new_exec(); |
| |
| 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 |
| /* |
| * Control the relaxed ABI allowing tagged user addresses into the kernel. |
| */ |
| static unsigned int tagged_addr_disabled; |
| |
| long set_tagged_addr_ctrl(struct task_struct *task, unsigned long arg) |
| { |
| unsigned long valid_mask = PR_TAGGED_ADDR_ENABLE; |
| struct thread_info *ti = task_thread_info(task); |
| |
| if (is_compat_thread(ti)) |
| return -EINVAL; |
| |
| if (system_supports_mte()) |
| valid_mask |= PR_MTE_TCF_SYNC | PR_MTE_TCF_ASYNC \ |
| | PR_MTE_TAG_MASK; |
| |
| if (arg & ~valid_mask) |
| return -EINVAL; |
| |
| /* |
| * Do not allow the enabling of the tagged address ABI if globally |
| * disabled via sysctl abi.tagged_addr_disabled. |
| */ |
| if (arg & PR_TAGGED_ADDR_ENABLE && tagged_addr_disabled) |
| return -EINVAL; |
| |
| 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(struct task_struct *task) |
| { |
| long ret = 0; |
| struct thread_info *ti = task_thread_info(task); |
| |
| if (is_compat_thread(ti)) |
| return -EINVAL; |
| |
| if (test_ti_thread_flag(ti, TIF_TAGGED_ADDR)) |
| ret = PR_TAGGED_ADDR_ENABLE; |
| |
| ret |= get_mte_ctrl(task); |
| |
| return ret; |
| } |
| |
| /* |
| * Global sysctl to disable the tagged user addresses support. This control |
| * only prevents the tagged address ABI enabling via prctl() and does not |
| * disable it for tasks that already opted in to the relaxed ABI. |
| */ |
| |
| static struct ctl_table tagged_addr_sysctl_table[] = { |
| { |
| .procname = "tagged_addr_disabled", |
| .mode = 0644, |
| .data = &tagged_addr_disabled, |
| .maxlen = sizeof(int), |
| .proc_handler = proc_dointvec_minmax, |
| .extra1 = SYSCTL_ZERO, |
| .extra2 = SYSCTL_ONE, |
| }, |
| { } |
| }; |
| |
| static int __init tagged_addr_init(void) |
| { |
| if (!register_sysctl("abi", tagged_addr_sysctl_table)) |
| return -EINVAL; |
| return 0; |
| } |
| |
| core_initcall(tagged_addr_init); |
| #endif /* CONFIG_ARM64_TAGGED_ADDR_ABI */ |
| |
| #ifdef CONFIG_BINFMT_ELF |
| int arch_elf_adjust_prot(int prot, const struct arch_elf_state *state, |
| bool has_interp, bool is_interp) |
| { |
| /* |
| * For dynamically linked executables the interpreter is |
| * responsible for setting PROT_BTI on everything except |
| * itself. |
| */ |
| if (is_interp != has_interp) |
| return prot; |
| |
| if (!(state->flags & ARM64_ELF_BTI)) |
| return prot; |
| |
| if (prot & PROT_EXEC) |
| prot |= PROT_BTI; |
| |
| return prot; |
| } |
| #endif |