diff options
Diffstat (limited to 'arch/arm64/kernel/traps.c')
| -rw-r--r-- | arch/arm64/kernel/traps.c | 1168 |
1 files changed, 962 insertions, 206 deletions
diff --git a/arch/arm64/kernel/traps.c b/arch/arm64/kernel/traps.c index 7ffadddb645d..914282016069 100644 --- a/arch/arm64/kernel/traps.c +++ b/arch/arm64/kernel/traps.c @@ -1,25 +1,16 @@ +// SPDX-License-Identifier: GPL-2.0-only /* * Based on arch/arm/kernel/traps.c * * Copyright (C) 1995-2009 Russell King * Copyright (C) 2012 ARM Ltd. - * - * This program is free software; you can redistribute it and/or modify - * it under the terms of the GNU General Public License version 2 as - * published by the Free Software Foundation. - * - * This program is distributed in the hope that it will be useful, - * but WITHOUT ANY WARRANTY; without even the implied warranty of - * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the - * GNU General Public License for more details. - * - * You should have received a copy of the GNU General Public License - * along with this program. If not, see <http://www.gnu.org/licenses/>. */ +#include <linux/bug.h> +#include <linux/context_tracking.h> #include <linux/signal.h> -#include <linux/personality.h> #include <linux/kallsyms.h> +#include <linux/kprobes.h> #include <linux/spinlock.h> #include <linux/uaccess.h> #include <linux/hardirq.h> @@ -27,172 +18,168 @@ #include <linux/module.h> #include <linux/kexec.h> #include <linux/delay.h> +#include <linux/efi.h> #include <linux/init.h> -#include <linux/sched.h> +#include <linux/sched/signal.h> +#include <linux/sched/debug.h> +#include <linux/sched/task_stack.h> +#include <linux/sizes.h> #include <linux/syscalls.h> +#include <linux/mm_types.h> +#include <linux/kasan.h> +#include <linux/ubsan.h> +#include <linux/cfi.h> #include <asm/atomic.h> +#include <asm/bug.h> +#include <asm/cpufeature.h> +#include <asm/daifflags.h> #include <asm/debug-monitors.h> +#include <asm/efi.h> +#include <asm/esr.h> +#include <asm/exception.h> +#include <asm/extable.h> +#include <asm/insn.h> +#include <asm/kprobes.h> +#include <asm/text-patching.h> #include <asm/traps.h> +#include <asm/smp.h> +#include <asm/stack_pointer.h> #include <asm/stacktrace.h> -#include <asm/exception.h> #include <asm/system_misc.h> +#include <asm/sysreg.h> -static const char *handler[]= { - "Synchronous Abort", - "IRQ", - "FIQ", - "Error" -}; - -int show_unhandled_signals = 1; +static bool __kprobes __check_eq(unsigned long pstate) +{ + return (pstate & PSR_Z_BIT) != 0; +} -/* - * Dump out the contents of some memory nicely... - */ -static void dump_mem(const char *lvl, const char *str, unsigned long bottom, - unsigned long top) +static bool __kprobes __check_ne(unsigned long pstate) { - unsigned long first; - mm_segment_t fs; - int i; + return (pstate & PSR_Z_BIT) == 0; +} - /* - * We need to switch to kernel mode so that we can use __get_user - * to safely read from kernel space. Note that we now dump the - * code first, just in case the backtrace kills us. - */ - fs = get_fs(); - set_fs(KERNEL_DS); - - printk("%s%s(0x%016lx to 0x%016lx)\n", lvl, str, bottom, top); - - for (first = bottom & ~31; first < top; first += 32) { - unsigned long p; - char str[sizeof(" 12345678") * 8 + 1]; - - memset(str, ' ', sizeof(str)); - str[sizeof(str) - 1] = '\0'; - - for (p = first, i = 0; i < 8 && p < top; i++, p += 4) { - if (p >= bottom && p < top) { - unsigned int val; - if (__get_user(val, (unsigned int *)p) == 0) - sprintf(str + i * 9, " %08x", val); - else - sprintf(str + i * 9, " ????????"); - } - } - printk("%s%04lx:%s\n", lvl, first & 0xffff, str); - } +static bool __kprobes __check_cs(unsigned long pstate) +{ + return (pstate & PSR_C_BIT) != 0; +} - set_fs(fs); +static bool __kprobes __check_cc(unsigned long pstate) +{ + return (pstate & PSR_C_BIT) == 0; } -static void dump_backtrace_entry(unsigned long where, unsigned long stack) +static bool __kprobes __check_mi(unsigned long pstate) { - print_ip_sym(where); - if (in_exception_text(where)) - dump_mem("", "Exception stack", stack, - stack + sizeof(struct pt_regs)); + return (pstate & PSR_N_BIT) != 0; } -static void dump_instr(const char *lvl, struct pt_regs *regs) +static bool __kprobes __check_pl(unsigned long pstate) { - unsigned long addr = instruction_pointer(regs); - mm_segment_t fs; - char str[sizeof("00000000 ") * 5 + 2 + 1], *p = str; - int i; + return (pstate & PSR_N_BIT) == 0; +} - /* - * We need to switch to kernel mode so that we can use __get_user - * to safely read from kernel space. Note that we now dump the - * code first, just in case the backtrace kills us. - */ - fs = get_fs(); - set_fs(KERNEL_DS); +static bool __kprobes __check_vs(unsigned long pstate) +{ + return (pstate & PSR_V_BIT) != 0; +} - for (i = -4; i < 1; i++) { - unsigned int val, bad; +static bool __kprobes __check_vc(unsigned long pstate) +{ + return (pstate & PSR_V_BIT) == 0; +} - bad = __get_user(val, &((u32 *)addr)[i]); +static bool __kprobes __check_hi(unsigned long pstate) +{ + pstate &= ~(pstate >> 1); /* PSR_C_BIT &= ~PSR_Z_BIT */ + return (pstate & PSR_C_BIT) != 0; +} - if (!bad) - p += sprintf(p, i == 0 ? "(%08x) " : "%08x ", val); - else { - p += sprintf(p, "bad PC value"); - break; - } - } - printk("%sCode: %s\n", lvl, str); +static bool __kprobes __check_ls(unsigned long pstate) +{ + pstate &= ~(pstate >> 1); /* PSR_C_BIT &= ~PSR_Z_BIT */ + return (pstate & PSR_C_BIT) == 0; +} - set_fs(fs); +static bool __kprobes __check_ge(unsigned long pstate) +{ + pstate ^= (pstate << 3); /* PSR_N_BIT ^= PSR_V_BIT */ + return (pstate & PSR_N_BIT) == 0; } -static void dump_backtrace(struct pt_regs *regs, struct task_struct *tsk) +static bool __kprobes __check_lt(unsigned long pstate) { - struct stackframe frame; - const register unsigned long current_sp asm ("sp"); + pstate ^= (pstate << 3); /* PSR_N_BIT ^= PSR_V_BIT */ + return (pstate & PSR_N_BIT) != 0; +} - pr_debug("%s(regs = %p tsk = %p)\n", __func__, regs, tsk); +static bool __kprobes __check_gt(unsigned long pstate) +{ + /*PSR_N_BIT ^= PSR_V_BIT */ + unsigned long temp = pstate ^ (pstate << 3); - if (!tsk) - tsk = current; + temp |= (pstate << 1); /*PSR_N_BIT |= PSR_Z_BIT */ + return (temp & PSR_N_BIT) == 0; +} - if (regs) { - frame.fp = regs->regs[29]; - frame.sp = regs->sp; - frame.pc = regs->pc; - } else if (tsk == current) { - frame.fp = (unsigned long)__builtin_frame_address(0); - frame.sp = current_sp; - frame.pc = (unsigned long)dump_backtrace; - } else { - /* - * task blocked in __switch_to - */ - frame.fp = thread_saved_fp(tsk); - frame.sp = thread_saved_sp(tsk); - frame.pc = thread_saved_pc(tsk); - } +static bool __kprobes __check_le(unsigned long pstate) +{ + /*PSR_N_BIT ^= PSR_V_BIT */ + unsigned long temp = pstate ^ (pstate << 3); - printk("Call trace:\n"); - while (1) { - unsigned long where = frame.pc; - int ret; + temp |= (pstate << 1); /*PSR_N_BIT |= PSR_Z_BIT */ + return (temp & PSR_N_BIT) != 0; +} - ret = unwind_frame(&frame); - if (ret < 0) - break; - dump_backtrace_entry(where, frame.sp); - } +static bool __kprobes __check_al(unsigned long pstate) +{ + return true; } -void show_stack(struct task_struct *tsk, unsigned long *sp) +/* + * Note that the ARMv8 ARM calls condition code 0b1111 "nv", but states that + * it behaves identically to 0b1110 ("al"). + */ +pstate_check_t * const aarch32_opcode_cond_checks[16] = { + __check_eq, __check_ne, __check_cs, __check_cc, + __check_mi, __check_pl, __check_vs, __check_vc, + __check_hi, __check_ls, __check_ge, __check_lt, + __check_gt, __check_le, __check_al, __check_al +}; + +int show_unhandled_signals = 0; + +void dump_kernel_instr(unsigned long kaddr) { - dump_backtrace(NULL, tsk); - barrier(); + char str[sizeof("00000000 ") * 5 + 2 + 1], *p = str; + int i; + + if (!is_ttbr1_addr(kaddr)) + return; + + for (i = -4; i < 1; i++) { + unsigned int val, bad; + + bad = aarch64_insn_read(&((u32 *)kaddr)[i], &val); + + if (!bad) + p += sprintf(p, i == 0 ? "(%08x) " : "%08x ", val); + else + p += sprintf(p, i == 0 ? "(????????) " : "???????? "); + } + + printk(KERN_EMERG "Code: %s\n", str); } -#ifdef CONFIG_PREEMPT -#define S_PREEMPT " PREEMPT" -#else -#define S_PREEMPT "" -#endif -#ifdef CONFIG_SMP #define S_SMP " SMP" -#else -#define S_SMP "" -#endif -static int __die(const char *str, int err, struct thread_info *thread, - struct pt_regs *regs) +static int __die(const char *str, long err, struct pt_regs *regs) { - struct task_struct *tsk = thread->task; static int die_counter; int ret; + unsigned long addr = instruction_pointer(regs); - pr_emerg("Internal error: %s: %x [#%d]" S_PREEMPT S_SMP "\n", + pr_emerg("Internal error: %s: %016lx [#%d] " S_SMP "\n", str, err, ++die_counter); /* trap and error numbers are mostly meaningless on ARM */ @@ -201,16 +188,12 @@ static int __die(const char *str, int err, struct thread_info *thread, return ret; print_modules(); - __show_regs(regs); - pr_emerg("Process %.*s (pid: %d, stack limit = 0x%p)\n", - TASK_COMM_LEN, tsk->comm, task_pid_nr(tsk), thread + 1); - - if (!user_mode(regs) || in_interrupt()) { - dump_mem(KERN_EMERG, "Stack: ", regs->sp, - THREAD_SIZE + (unsigned long)task_stack_page(tsk)); - dump_backtrace(regs, tsk); - dump_instr(KERN_EMERG, regs); - } + show_regs(regs); + + if (user_mode(regs)) + return ret; + + dump_kernel_instr(addr); return ret; } @@ -220,128 +203,901 @@ static DEFINE_RAW_SPINLOCK(die_lock); /* * This function is protected against re-entrancy. */ -void die(const char *str, struct pt_regs *regs, int err) +void die(const char *str, struct pt_regs *regs, long err) { - struct thread_info *thread = current_thread_info(); int ret; + unsigned long flags; + + raw_spin_lock_irqsave(&die_lock, flags); oops_enter(); - raw_spin_lock_irq(&die_lock); console_verbose(); bust_spinlocks(1); - ret = __die(str, err, thread, regs); + ret = __die(str, err, regs); - if (regs && kexec_should_crash(thread->task)) + if (regs && kexec_should_crash(current)) crash_kexec(regs); bust_spinlocks(0); add_taint(TAINT_DIE, LOCKDEP_NOW_UNRELIABLE); - raw_spin_unlock_irq(&die_lock); oops_exit(); if (in_interrupt()) - panic("Fatal exception in interrupt"); + panic("%s: Fatal exception in interrupt", str); if (panic_on_oops) - panic("Fatal exception"); + panic("%s: Fatal exception", str); + + raw_spin_unlock_irqrestore(&die_lock, flags); + if (ret != NOTIFY_STOP) - do_exit(SIGSEGV); + make_task_dead(SIGSEGV); +} + +static void arm64_show_signal(int signo, const char *str) +{ + static DEFINE_RATELIMIT_STATE(rs, DEFAULT_RATELIMIT_INTERVAL, + DEFAULT_RATELIMIT_BURST); + struct task_struct *tsk = current; + unsigned long esr = tsk->thread.fault_code; + struct pt_regs *regs = task_pt_regs(tsk); + + /* Leave if the signal won't be shown */ + if (!show_unhandled_signals || + !unhandled_signal(tsk, signo) || + !__ratelimit(&rs)) + return; + + pr_info("%s[%d]: unhandled exception: ", tsk->comm, task_pid_nr(tsk)); + if (esr) + pr_cont("%s, ESR 0x%016lx, ", esr_get_class_string(esr), esr); + + pr_cont("%s", str); + print_vma_addr(KERN_CONT " in ", regs->pc); + pr_cont("\n"); + __show_regs(regs); +} + +void arm64_force_sig_fault(int signo, int code, unsigned long far, + const char *str) +{ + arm64_show_signal(signo, str); + if (signo == SIGKILL) + force_sig(SIGKILL); + else + force_sig_fault(signo, code, (void __user *)far); +} + +void arm64_force_sig_fault_pkey(unsigned long far, const char *str, int pkey) +{ + arm64_show_signal(SIGSEGV, str); + force_sig_pkuerr((void __user *)far, pkey); +} + +void arm64_force_sig_mceerr(int code, unsigned long far, short lsb, + const char *str) +{ + arm64_show_signal(SIGBUS, str); + force_sig_mceerr(code, (void __user *)far, lsb); +} + +void arm64_force_sig_ptrace_errno_trap(int errno, unsigned long far, + const char *str) +{ + arm64_show_signal(SIGTRAP, str); + force_sig_ptrace_errno_trap(errno, (void __user *)far); } void arm64_notify_die(const char *str, struct pt_regs *regs, - struct siginfo *info, int err) + int signo, int sicode, unsigned long far, + unsigned long err) +{ + if (user_mode(regs)) { + WARN_ON(regs != current_pt_regs()); + current->thread.fault_address = 0; + current->thread.fault_code = err; + + arm64_force_sig_fault(signo, sicode, far, str); + } else { + die(str, regs, err); + } +} + +#ifdef CONFIG_COMPAT +#define PSTATE_IT_1_0_SHIFT 25 +#define PSTATE_IT_1_0_MASK (0x3 << PSTATE_IT_1_0_SHIFT) +#define PSTATE_IT_7_2_SHIFT 10 +#define PSTATE_IT_7_2_MASK (0x3f << PSTATE_IT_7_2_SHIFT) + +static u32 compat_get_it_state(struct pt_regs *regs) +{ + u32 it, pstate = regs->pstate; + + it = (pstate & PSTATE_IT_1_0_MASK) >> PSTATE_IT_1_0_SHIFT; + it |= ((pstate & PSTATE_IT_7_2_MASK) >> PSTATE_IT_7_2_SHIFT) << 2; + + return it; +} + +static void compat_set_it_state(struct pt_regs *regs, u32 it) +{ + u32 pstate_it; + + pstate_it = (it << PSTATE_IT_1_0_SHIFT) & PSTATE_IT_1_0_MASK; + pstate_it |= ((it >> 2) << PSTATE_IT_7_2_SHIFT) & PSTATE_IT_7_2_MASK; + + regs->pstate &= ~PSR_AA32_IT_MASK; + regs->pstate |= pstate_it; +} + +static void advance_itstate(struct pt_regs *regs) +{ + u32 it; + + /* ARM mode */ + if (!(regs->pstate & PSR_AA32_T_BIT) || + !(regs->pstate & PSR_AA32_IT_MASK)) + return; + + it = compat_get_it_state(regs); + + /* + * If this is the last instruction of the block, wipe the IT + * state. Otherwise advance it. + */ + if (!(it & 7)) + it = 0; + else + it = (it & 0xe0) | ((it << 1) & 0x1f); + + compat_set_it_state(regs, it); +} +#else +static void advance_itstate(struct pt_regs *regs) { +} +#endif + +void arm64_skip_faulting_instruction(struct pt_regs *regs, unsigned long size) +{ + regs->pc += size; + + /* + * If we were single stepping, we want to get the step exception after + * we return from the trap. + */ if (user_mode(regs)) - force_sig_info(info->si_signo, info, current); + user_fastforward_single_step(current); + + if (compat_user_mode(regs)) + advance_itstate(regs); else - die(str, regs, err); + regs->pstate &= ~PSR_BTYPE_MASK; } -asmlinkage void __exception do_undefinstr(struct pt_regs *regs) +static int user_insn_read(struct pt_regs *regs, u32 *insnp) { - siginfo_t info; - void __user *pc = (void __user *)instruction_pointer(regs); + u32 instr; + unsigned long pc = instruction_pointer(regs); + + if (compat_thumb_mode(regs)) { + /* 16-bit Thumb instruction */ + __le16 instr_le; + if (get_user(instr_le, (__le16 __user *)pc)) + return -EFAULT; + instr = le16_to_cpu(instr_le); + if (aarch32_insn_is_wide(instr)) { + u32 instr2; + + if (get_user(instr_le, (__le16 __user *)(pc + 2))) + return -EFAULT; + instr2 = le16_to_cpu(instr_le); + instr = (instr << 16) | instr2; + } + } else { + /* 32-bit ARM instruction */ + __le32 instr_le; + if (get_user(instr_le, (__le32 __user *)pc)) + return -EFAULT; + instr = le32_to_cpu(instr_le); + } + + *insnp = instr; + return 0; +} + +void force_signal_inject(int signal, int code, unsigned long address, unsigned long err) +{ + const char *desc; + struct pt_regs *regs = current_pt_regs(); + + if (WARN_ON(!user_mode(regs))) + return; + + switch (signal) { + case SIGILL: + desc = "undefined instruction"; + break; + case SIGSEGV: + desc = "illegal memory access"; + break; + default: + desc = "unknown or unrecoverable error"; + break; + } + + /* Force signals we don't understand to SIGKILL */ + if (WARN_ON(signal != SIGKILL && + siginfo_layout(signal, code) != SIL_FAULT)) { + signal = SIGKILL; + } + + arm64_notify_die(desc, regs, signal, code, address, err); +} + +/* + * Set up process info to signal segmentation fault - called on access error. + */ +void arm64_notify_segfault(unsigned long addr) +{ + int code; + + mmap_read_lock(current->mm); + if (find_vma(current->mm, untagged_addr(addr)) == NULL) + code = SEGV_MAPERR; + else + code = SEGV_ACCERR; + mmap_read_unlock(current->mm); + + force_signal_inject(SIGSEGV, code, addr, 0); +} + +void do_el0_undef(struct pt_regs *regs, unsigned long esr) +{ + u32 insn; /* check for AArch32 breakpoint instructions */ - if (!aarch32_break_handler(regs)) + if (try_handle_aarch32_break(regs)) + return; + + if (user_insn_read(regs, &insn)) + goto out_err; + + if (try_emulate_mrs(regs, insn)) return; - if (show_unhandled_signals && unhandled_signal(current, SIGILL) && - printk_ratelimit()) { - pr_info("%s[%d]: undefined instruction: pc=%p\n", - current->comm, task_pid_nr(current), pc); - dump_instr(KERN_INFO, regs); + if (try_emulate_armv8_deprecated(regs, insn)) + return; + +out_err: + force_signal_inject(SIGILL, ILL_ILLOPC, regs->pc, 0); +} + +void do_el1_undef(struct pt_regs *regs, unsigned long esr) +{ + u32 insn; + + if (aarch64_insn_read((void *)regs->pc, &insn)) + goto out_err; + + if (try_emulate_el1_ssbs(regs, insn)) + return; + +out_err: + die("Oops - Undefined instruction", regs, esr); +} + +void do_el0_bti(struct pt_regs *regs) +{ + force_signal_inject(SIGILL, ILL_ILLOPC, regs->pc, 0); +} + +void do_el1_bti(struct pt_regs *regs, unsigned long esr) +{ + if (efi_runtime_fixup_exception(regs, "BTI violation")) { + regs->pstate &= ~PSR_BTYPE_MASK; + return; + } + die("Oops - BTI", regs, esr); +} + +void do_el0_gcs(struct pt_regs *regs, unsigned long esr) +{ + force_signal_inject(SIGSEGV, SEGV_CPERR, regs->pc, 0); +} + +void do_el1_gcs(struct pt_regs *regs, unsigned long esr) +{ + die("Oops - GCS", regs, esr); +} + +void do_el0_fpac(struct pt_regs *regs, unsigned long esr) +{ + force_signal_inject(SIGILL, ILL_ILLOPN, regs->pc, esr); +} + +void do_el1_fpac(struct pt_regs *regs, unsigned long esr) +{ + /* + * Unexpected FPAC exception in the kernel: kill the task before it + * does any more harm. + */ + die("Oops - FPAC", regs, esr); +} + +void do_el0_mops(struct pt_regs *regs, unsigned long esr) +{ + arm64_mops_reset_regs(®s->user_regs, esr); + + /* + * If single stepping then finish the step before executing the + * prologue instruction. + */ + user_fastforward_single_step(current); +} + +void do_el1_mops(struct pt_regs *regs, unsigned long esr) +{ + arm64_mops_reset_regs(®s->user_regs, esr); + + kernel_fastforward_single_step(regs); +} + +#define __user_cache_maint(insn, address, res) \ + if (address >= TASK_SIZE_MAX) { \ + res = -EFAULT; \ + } else { \ + uaccess_ttbr0_enable(); \ + asm volatile ( \ + "1: " insn ", %1\n" \ + " mov %w0, #0\n" \ + "2:\n" \ + _ASM_EXTABLE_UACCESS_ERR(1b, 2b, %w0) \ + : "=r" (res) \ + : "r" (address)); \ + uaccess_ttbr0_disable(); \ + } + +static void user_cache_maint_handler(unsigned long esr, struct pt_regs *regs) +{ + unsigned long tagged_address, address; + int rt = ESR_ELx_SYS64_ISS_RT(esr); + int crm = (esr & ESR_ELx_SYS64_ISS_CRM_MASK) >> ESR_ELx_SYS64_ISS_CRM_SHIFT; + int ret = 0; + + tagged_address = pt_regs_read_reg(regs, rt); + address = untagged_addr(tagged_address); + + switch (crm) { + case ESR_ELx_SYS64_ISS_CRM_DC_CVAU: /* DC CVAU, gets promoted */ + __user_cache_maint("dc civac", address, ret); + break; + case ESR_ELx_SYS64_ISS_CRM_DC_CVAC: /* DC CVAC, gets promoted */ + __user_cache_maint("dc civac", address, ret); + break; + case ESR_ELx_SYS64_ISS_CRM_DC_CVADP: /* DC CVADP */ + __user_cache_maint("sys 3, c7, c13, 1", address, ret); + break; + case ESR_ELx_SYS64_ISS_CRM_DC_CVAP: /* DC CVAP */ + __user_cache_maint("sys 3, c7, c12, 1", address, ret); + break; + case ESR_ELx_SYS64_ISS_CRM_DC_CIVAC: /* DC CIVAC */ + __user_cache_maint("dc civac", address, ret); + break; + case ESR_ELx_SYS64_ISS_CRM_IC_IVAU: /* IC IVAU */ + __user_cache_maint("ic ivau", address, ret); + break; + default: + force_signal_inject(SIGILL, ILL_ILLOPC, regs->pc, 0); + return; + } + + if (ret) + arm64_notify_segfault(tagged_address); + else + arm64_skip_faulting_instruction(regs, AARCH64_INSN_SIZE); +} + +static void ctr_read_handler(unsigned long esr, struct pt_regs *regs) +{ + int rt = ESR_ELx_SYS64_ISS_RT(esr); + unsigned long val = arm64_ftr_reg_user_value(&arm64_ftr_reg_ctrel0); + + if (cpus_have_final_cap(ARM64_WORKAROUND_1542419)) { + /* Hide DIC so that we can trap the unnecessary maintenance...*/ + val &= ~BIT(CTR_EL0_DIC_SHIFT); + + /* ... and fake IminLine to reduce the number of traps. */ + val &= ~CTR_EL0_IminLine_MASK; + val |= (PAGE_SHIFT - 2) & CTR_EL0_IminLine_MASK; } - info.si_signo = SIGILL; - info.si_errno = 0; - info.si_code = ILL_ILLOPC; - info.si_addr = pc; + pt_regs_write_reg(regs, rt, val); - arm64_notify_die("Oops - undefined instruction", regs, &info, 0); + arm64_skip_faulting_instruction(regs, AARCH64_INSN_SIZE); } -long compat_arm_syscall(struct pt_regs *regs); +static void cntvct_read_handler(unsigned long esr, struct pt_regs *regs) +{ + if (test_thread_flag(TIF_TSC_SIGSEGV)) { + force_sig(SIGSEGV); + } else { + int rt = ESR_ELx_SYS64_ISS_RT(esr); + + pt_regs_write_reg(regs, rt, arch_timer_read_counter()); + arm64_skip_faulting_instruction(regs, AARCH64_INSN_SIZE); + } +} -asmlinkage long do_ni_syscall(struct pt_regs *regs) +static void cntfrq_read_handler(unsigned long esr, struct pt_regs *regs) { + if (test_thread_flag(TIF_TSC_SIGSEGV)) { + force_sig(SIGSEGV); + } else { + int rt = ESR_ELx_SYS64_ISS_RT(esr); + + pt_regs_write_reg(regs, rt, arch_timer_get_rate()); + arm64_skip_faulting_instruction(regs, AARCH64_INSN_SIZE); + } +} + +static void mrs_handler(unsigned long esr, struct pt_regs *regs) +{ + u32 sysreg, rt; + + rt = ESR_ELx_SYS64_ISS_RT(esr); + sysreg = esr_sys64_to_sysreg(esr); + + if (do_emulate_mrs(regs, sysreg, rt) != 0) + force_signal_inject(SIGILL, ILL_ILLOPC, regs->pc, 0); +} + +static void wfi_handler(unsigned long esr, struct pt_regs *regs) +{ + arm64_skip_faulting_instruction(regs, AARCH64_INSN_SIZE); +} + +struct sys64_hook { + unsigned long esr_mask; + unsigned long esr_val; + void (*handler)(unsigned long esr, struct pt_regs *regs); +}; + +static const struct sys64_hook sys64_hooks[] = { + { + .esr_mask = ESR_ELx_SYS64_ISS_EL0_CACHE_OP_MASK, + .esr_val = ESR_ELx_SYS64_ISS_EL0_CACHE_OP_VAL, + .handler = user_cache_maint_handler, + }, + { + /* Trap read access to CTR_EL0 */ + .esr_mask = ESR_ELx_SYS64_ISS_SYS_OP_MASK, + .esr_val = ESR_ELx_SYS64_ISS_SYS_CTR_READ, + .handler = ctr_read_handler, + }, + { + /* Trap read access to CNTVCT_EL0 */ + .esr_mask = ESR_ELx_SYS64_ISS_SYS_OP_MASK, + .esr_val = ESR_ELx_SYS64_ISS_SYS_CNTVCT, + .handler = cntvct_read_handler, + }, + { + /* Trap read access to CNTVCTSS_EL0 */ + .esr_mask = ESR_ELx_SYS64_ISS_SYS_OP_MASK, + .esr_val = ESR_ELx_SYS64_ISS_SYS_CNTVCTSS, + .handler = cntvct_read_handler, + }, + { + /* Trap read access to CNTFRQ_EL0 */ + .esr_mask = ESR_ELx_SYS64_ISS_SYS_OP_MASK, + .esr_val = ESR_ELx_SYS64_ISS_SYS_CNTFRQ, + .handler = cntfrq_read_handler, + }, + { + /* Trap read access to CPUID registers */ + .esr_mask = ESR_ELx_SYS64_ISS_SYS_MRS_OP_MASK, + .esr_val = ESR_ELx_SYS64_ISS_SYS_MRS_OP_VAL, + .handler = mrs_handler, + }, + { + /* Trap WFI instructions executed in userspace */ + .esr_mask = ESR_ELx_WFx_MASK, + .esr_val = ESR_ELx_WFx_WFI_VAL, + .handler = wfi_handler, + }, + {}, +}; + #ifdef CONFIG_COMPAT - long ret; - if (is_compat_task()) { - ret = compat_arm_syscall(regs); - if (ret != -ENOSYS) - return ret; +static bool cp15_cond_valid(unsigned long esr, struct pt_regs *regs) +{ + int cond; + + /* Only a T32 instruction can trap without CV being set */ + if (!(esr & ESR_ELx_CV)) { + u32 it; + + it = compat_get_it_state(regs); + if (!it) + return true; + + cond = it >> 4; + } else { + cond = (esr & ESR_ELx_COND_MASK) >> ESR_ELx_COND_SHIFT; } -#endif - if (show_unhandled_signals && printk_ratelimit()) { - pr_info("%s[%d]: syscall %d\n", current->comm, - task_pid_nr(current), (int)regs->syscallno); - dump_instr("", regs); - if (user_mode(regs)) - __show_regs(regs); + return aarch32_opcode_cond_checks[cond](regs->pstate); +} + +static void compat_cntfrq_read_handler(unsigned long esr, struct pt_regs *regs) +{ + int reg = (esr & ESR_ELx_CP15_32_ISS_RT_MASK) >> ESR_ELx_CP15_32_ISS_RT_SHIFT; + + pt_regs_write_reg(regs, reg, arch_timer_get_rate()); + arm64_skip_faulting_instruction(regs, 4); +} + +static const struct sys64_hook cp15_32_hooks[] = { + { + .esr_mask = ESR_ELx_CP15_32_ISS_SYS_MASK, + .esr_val = ESR_ELx_CP15_32_ISS_SYS_CNTFRQ, + .handler = compat_cntfrq_read_handler, + }, + {}, +}; + +static void compat_cntvct_read_handler(unsigned long esr, struct pt_regs *regs) +{ + int rt = (esr & ESR_ELx_CP15_64_ISS_RT_MASK) >> ESR_ELx_CP15_64_ISS_RT_SHIFT; + int rt2 = (esr & ESR_ELx_CP15_64_ISS_RT2_MASK) >> ESR_ELx_CP15_64_ISS_RT2_SHIFT; + u64 val = arch_timer_read_counter(); + + pt_regs_write_reg(regs, rt, lower_32_bits(val)); + pt_regs_write_reg(regs, rt2, upper_32_bits(val)); + arm64_skip_faulting_instruction(regs, 4); +} + +static const struct sys64_hook cp15_64_hooks[] = { + { + .esr_mask = ESR_ELx_CP15_64_ISS_SYS_MASK, + .esr_val = ESR_ELx_CP15_64_ISS_SYS_CNTVCT, + .handler = compat_cntvct_read_handler, + }, + { + .esr_mask = ESR_ELx_CP15_64_ISS_SYS_MASK, + .esr_val = ESR_ELx_CP15_64_ISS_SYS_CNTVCTSS, + .handler = compat_cntvct_read_handler, + }, + {}, +}; + +void do_el0_cp15(unsigned long esr, struct pt_regs *regs) +{ + const struct sys64_hook *hook, *hook_base; + + if (!cp15_cond_valid(esr, regs)) { + /* + * There is no T16 variant of a CP access, so we + * always advance PC by 4 bytes. + */ + arm64_skip_faulting_instruction(regs, 4); + return; + } + + switch (ESR_ELx_EC(esr)) { + case ESR_ELx_EC_CP15_32: + hook_base = cp15_32_hooks; + break; + case ESR_ELx_EC_CP15_64: + hook_base = cp15_64_hooks; + break; + default: + do_el0_undef(regs, esr); + return; } - return sys_ni_syscall(); + for (hook = hook_base; hook->handler; hook++) + if ((hook->esr_mask & esr) == hook->esr_val) { + hook->handler(esr, regs); + return; + } + + /* + * New cp15 instructions may previously have been undefined at + * EL0. Fall back to our usual undefined instruction handler + * so that we handle these consistently. + */ + do_el0_undef(regs, esr); +} +#endif + +void do_el0_sys(unsigned long esr, struct pt_regs *regs) +{ + const struct sys64_hook *hook; + + for (hook = sys64_hooks; hook->handler; hook++) + if ((hook->esr_mask & esr) == hook->esr_val) { + hook->handler(esr, regs); + return; + } + + /* + * New SYS instructions may previously have been undefined at EL0. Fall + * back to our usual undefined instruction handler so that we handle + * these consistently. + */ + do_el0_undef(regs, esr); +} + +static const char *esr_class_str[] = { + [0 ... ESR_ELx_EC_MAX] = "UNRECOGNIZED EC", + [ESR_ELx_EC_UNKNOWN] = "Unknown/Uncategorized", + [ESR_ELx_EC_WFx] = "WFI/WFE", + [ESR_ELx_EC_CP15_32] = "CP15 MCR/MRC", + [ESR_ELx_EC_CP15_64] = "CP15 MCRR/MRRC", + [ESR_ELx_EC_CP14_MR] = "CP14 MCR/MRC", + [ESR_ELx_EC_CP14_LS] = "CP14 LDC/STC", + [ESR_ELx_EC_FP_ASIMD] = "ASIMD", + [ESR_ELx_EC_CP10_ID] = "CP10 MRC/VMRS", + [ESR_ELx_EC_PAC] = "PAC", + [ESR_ELx_EC_CP14_64] = "CP14 MCRR/MRRC", + [ESR_ELx_EC_BTI] = "BTI", + [ESR_ELx_EC_ILL] = "PSTATE.IL", + [ESR_ELx_EC_SVC32] = "SVC (AArch32)", + [ESR_ELx_EC_HVC32] = "HVC (AArch32)", + [ESR_ELx_EC_SMC32] = "SMC (AArch32)", + [ESR_ELx_EC_SVC64] = "SVC (AArch64)", + [ESR_ELx_EC_HVC64] = "HVC (AArch64)", + [ESR_ELx_EC_SMC64] = "SMC (AArch64)", + [ESR_ELx_EC_SYS64] = "MSR/MRS (AArch64)", + [ESR_ELx_EC_SVE] = "SVE", + [ESR_ELx_EC_ERET] = "ERET/ERETAA/ERETAB", + [ESR_ELx_EC_FPAC] = "FPAC", + [ESR_ELx_EC_SME] = "SME", + [ESR_ELx_EC_IMP_DEF] = "EL3 IMP DEF", + [ESR_ELx_EC_IABT_LOW] = "IABT (lower EL)", + [ESR_ELx_EC_IABT_CUR] = "IABT (current EL)", + [ESR_ELx_EC_PC_ALIGN] = "PC Alignment", + [ESR_ELx_EC_DABT_LOW] = "DABT (lower EL)", + [ESR_ELx_EC_DABT_CUR] = "DABT (current EL)", + [ESR_ELx_EC_SP_ALIGN] = "SP Alignment", + [ESR_ELx_EC_MOPS] = "MOPS", + [ESR_ELx_EC_FP_EXC32] = "FP (AArch32)", + [ESR_ELx_EC_FP_EXC64] = "FP (AArch64)", + [ESR_ELx_EC_GCS] = "Guarded Control Stack", + [ESR_ELx_EC_SERROR] = "SError", + [ESR_ELx_EC_BREAKPT_LOW] = "Breakpoint (lower EL)", + [ESR_ELx_EC_BREAKPT_CUR] = "Breakpoint (current EL)", + [ESR_ELx_EC_SOFTSTP_LOW] = "Software Step (lower EL)", + [ESR_ELx_EC_SOFTSTP_CUR] = "Software Step (current EL)", + [ESR_ELx_EC_WATCHPT_LOW] = "Watchpoint (lower EL)", + [ESR_ELx_EC_WATCHPT_CUR] = "Watchpoint (current EL)", + [ESR_ELx_EC_BKPT32] = "BKPT (AArch32)", + [ESR_ELx_EC_VECTOR32] = "Vector catch (AArch32)", + [ESR_ELx_EC_BRK64] = "BRK (AArch64)", +}; + +const char *esr_get_class_string(unsigned long esr) +{ + return esr_class_str[ESR_ELx_EC(esr)]; } /* - * bad_mode handles the impossible case in the exception vector. + * bad_el0_sync handles unexpected, but potentially recoverable synchronous + * exceptions taken from EL0. */ -asmlinkage void bad_mode(struct pt_regs *regs, int reason, unsigned int esr) +void bad_el0_sync(struct pt_regs *regs, int reason, unsigned long esr) +{ + unsigned long pc = instruction_pointer(regs); + + current->thread.fault_address = 0; + current->thread.fault_code = esr; + + arm64_force_sig_fault(SIGILL, ILL_ILLOPC, pc, + "Bad EL0 synchronous exception"); +} + +DEFINE_PER_CPU(unsigned long [OVERFLOW_STACK_SIZE/sizeof(long)], overflow_stack) + __aligned(16); + +void __noreturn panic_bad_stack(struct pt_regs *regs, unsigned long esr, unsigned long far) { - siginfo_t info; - void __user *pc = (void __user *)instruction_pointer(regs); + unsigned long tsk_stk = (unsigned long)current->stack; + unsigned long irq_stk = (unsigned long)this_cpu_read(irq_stack_ptr); + unsigned long ovf_stk = (unsigned long)this_cpu_ptr(overflow_stack); + console_verbose(); + pr_emerg("Insufficient stack space to handle exception!"); + + pr_emerg("ESR: 0x%016lx -- %s\n", esr, esr_get_class_string(esr)); + pr_emerg("FAR: 0x%016lx\n", far); + + pr_emerg("Task stack: [0x%016lx..0x%016lx]\n", + tsk_stk, tsk_stk + THREAD_SIZE); + pr_emerg("IRQ stack: [0x%016lx..0x%016lx]\n", + irq_stk, irq_stk + IRQ_STACK_SIZE); + pr_emerg("Overflow stack: [0x%016lx..0x%016lx]\n", + ovf_stk, ovf_stk + OVERFLOW_STACK_SIZE); - pr_crit("Bad mode in %s handler detected, code 0x%08x\n", - handler[reason], esr); __show_regs(regs); - info.si_signo = SIGILL; - info.si_errno = 0; - info.si_code = ILL_ILLOPC; - info.si_addr = pc; + /* + * We use nmi_panic to limit the potential for recursive overflows, and + * to get a better stack trace. + */ + nmi_panic(NULL, "kernel stack overflow"); + cpu_park_loop(); +} + +void __noreturn arm64_serror_panic(struct pt_regs *regs, unsigned long esr) +{ + add_taint(TAINT_MACHINE_CHECK, LOCKDEP_STILL_OK); + console_verbose(); + + pr_crit("SError Interrupt on CPU%d, code 0x%016lx -- %s\n", + smp_processor_id(), esr, esr_get_class_string(esr)); + if (regs) + __show_regs(regs); - arm64_notify_die("Oops - bad mode", regs, &info, 0); + nmi_panic(regs, "Asynchronous SError Interrupt"); + + cpu_park_loop(); +} + +bool arm64_is_fatal_ras_serror(struct pt_regs *regs, unsigned long esr) +{ + unsigned long aet = arm64_ras_serror_get_severity(esr); + + switch (aet) { + case ESR_ELx_AET_CE: /* corrected error */ + case ESR_ELx_AET_UEO: /* restartable, not yet consumed */ + /* + * The CPU can make progress. We may take UEO again as + * a more severe error. + */ + return false; + + case ESR_ELx_AET_UEU: /* Uncorrected Unrecoverable */ + case ESR_ELx_AET_UER: /* Uncorrected Recoverable */ + /* + * The CPU can't make progress. The exception may have + * been imprecise. + * + * Neoverse-N1 #1349291 means a non-KVM SError reported as + * Unrecoverable should be treated as Uncontainable. We + * call arm64_serror_panic() in both cases. + */ + return true; + + case ESR_ELx_AET_UC: /* Uncontainable or Uncategorized error */ + default: + /* Error has been silently propagated */ + arm64_serror_panic(regs, esr); + } +} + +void do_serror(struct pt_regs *regs, unsigned long esr) +{ + /* non-RAS errors are not containable */ + if (!arm64_is_ras_serror(esr) || arm64_is_fatal_ras_serror(regs, esr)) + arm64_serror_panic(regs, esr); +} + +/* GENERIC_BUG traps */ +#ifdef CONFIG_GENERIC_BUG +int is_valid_bugaddr(unsigned long addr) +{ + /* + * bug_brk_handler() only called for BRK #BUG_BRK_IMM. + * So the answer is trivial -- any spurious instances with no + * bug table entry will be rejected by report_bug() and passed + * back to the debug-monitors code and handled as a fatal + * unexpected debug exception. + */ + return 1; +} +#endif + +int bug_brk_handler(struct pt_regs *regs, unsigned long esr) +{ + switch (report_bug(regs->pc, regs)) { + case BUG_TRAP_TYPE_BUG: + die("Oops - BUG", regs, esr); + break; + + case BUG_TRAP_TYPE_WARN: + break; + + default: + /* unknown/unrecognised bug trap type */ + return DBG_HOOK_ERROR; + } + + /* If thread survives, skip over the BUG instruction and continue: */ + arm64_skip_faulting_instruction(regs, AARCH64_INSN_SIZE); + return DBG_HOOK_HANDLED; } -void __pte_error(const char *file, int line, unsigned long val) +#ifdef CONFIG_CFI +int cfi_brk_handler(struct pt_regs *regs, unsigned long esr) { - printk("%s:%d: bad pte %016lx.\n", file, line, val); + unsigned long target; + u32 type; + + target = pt_regs_read_reg(regs, FIELD_GET(CFI_BRK_IMM_TARGET, esr)); + type = (u32)pt_regs_read_reg(regs, FIELD_GET(CFI_BRK_IMM_TYPE, esr)); + + switch (report_cfi_failure(regs, regs->pc, &target, type)) { + case BUG_TRAP_TYPE_BUG: + die("Oops - CFI", regs, esr); + break; + + case BUG_TRAP_TYPE_WARN: + break; + + default: + return DBG_HOOK_ERROR; + } + + arm64_skip_faulting_instruction(regs, AARCH64_INSN_SIZE); + return DBG_HOOK_HANDLED; } +#endif /* CONFIG_CFI */ -void __pmd_error(const char *file, int line, unsigned long val) +int reserved_fault_brk_handler(struct pt_regs *regs, unsigned long esr) { - printk("%s:%d: bad pmd %016lx.\n", file, line, val); + pr_err("%s generated an invalid instruction at %pS!\n", + "Kernel text patching", + (void *)instruction_pointer(regs)); + + /* We cannot handle this */ + return DBG_HOOK_ERROR; } -void __pgd_error(const char *file, int line, unsigned long val) +#ifdef CONFIG_KASAN_SW_TAGS + +#define KASAN_ESR_RECOVER 0x20 +#define KASAN_ESR_WRITE 0x10 +#define KASAN_ESR_SIZE_MASK 0x0f +#define KASAN_ESR_SIZE(esr) (1 << ((esr) & KASAN_ESR_SIZE_MASK)) + +int kasan_brk_handler(struct pt_regs *regs, unsigned long esr) { - printk("%s:%d: bad pgd %016lx.\n", file, line, val); + bool recover = esr & KASAN_ESR_RECOVER; + bool write = esr & KASAN_ESR_WRITE; + size_t size = KASAN_ESR_SIZE(esr); + void *addr = (void *)regs->regs[0]; + u64 pc = regs->pc; + + kasan_report(addr, size, write, pc); + + /* + * The instrumentation allows to control whether we can proceed after + * a crash was detected. This is done by passing the -recover flag to + * the compiler. Disabling recovery allows to generate more compact + * code. + * + * Unfortunately disabling recovery doesn't work for the kernel right + * now. KASAN reporting is disabled in some contexts (for example when + * the allocator accesses slab object metadata; this is controlled by + * current->kasan_depth). All these accesses are detected by the tool, + * even though the reports for them are not printed. + * + * This is something that might be fixed at some point in the future. + */ + if (!recover) + die("Oops - KASAN", regs, esr); + + /* If thread survives, skip over the brk instruction and continue: */ + arm64_skip_faulting_instruction(regs, AARCH64_INSN_SIZE); + return DBG_HOOK_HANDLED; } +#endif -void __init trap_init(void) +#ifdef CONFIG_UBSAN_TRAP +int ubsan_brk_handler(struct pt_regs *regs, unsigned long esr) { - return; + die(report_ubsan_failure(esr & UBSAN_BRK_MASK), regs, esr); + return DBG_HOOK_HANDLED; } +#endif |