| // SPDX-License-Identifier: GPL-2.0-only |
| /* |
| * Based on arch/arm/mm/fault.c |
| * |
| * Copyright (C) 1995 Linus Torvalds |
| * Copyright (C) 1995-2004 Russell King |
| * Copyright (C) 2012 ARM Ltd. |
| */ |
| |
| #include <linux/acpi.h> |
| #include <linux/bitfield.h> |
| #include <linux/extable.h> |
| #include <linux/kfence.h> |
| #include <linux/signal.h> |
| #include <linux/mm.h> |
| #include <linux/hardirq.h> |
| #include <linux/init.h> |
| #include <linux/kasan.h> |
| #include <linux/kprobes.h> |
| #include <linux/uaccess.h> |
| #include <linux/page-flags.h> |
| #include <linux/sched/signal.h> |
| #include <linux/sched/debug.h> |
| #include <linux/highmem.h> |
| #include <linux/perf_event.h> |
| #include <linux/preempt.h> |
| #include <linux/hugetlb.h> |
| |
| #include <asm/acpi.h> |
| #include <asm/bug.h> |
| #include <asm/cmpxchg.h> |
| #include <asm/cpufeature.h> |
| #include <asm/exception.h> |
| #include <asm/daifflags.h> |
| #include <asm/debug-monitors.h> |
| #include <asm/esr.h> |
| #include <asm/kprobes.h> |
| #include <asm/mte.h> |
| #include <asm/processor.h> |
| #include <asm/sysreg.h> |
| #include <asm/system_misc.h> |
| #include <asm/tlbflush.h> |
| #include <asm/traps.h> |
| |
| struct fault_info { |
| int (*fn)(unsigned long far, unsigned int esr, |
| struct pt_regs *regs); |
| int sig; |
| int code; |
| const char *name; |
| }; |
| |
| static const struct fault_info fault_info[]; |
| static struct fault_info debug_fault_info[]; |
| |
| static inline const struct fault_info *esr_to_fault_info(unsigned int esr) |
| { |
| return fault_info + (esr & ESR_ELx_FSC); |
| } |
| |
| static inline const struct fault_info *esr_to_debug_fault_info(unsigned int esr) |
| { |
| return debug_fault_info + DBG_ESR_EVT(esr); |
| } |
| |
| static void data_abort_decode(unsigned int esr) |
| { |
| pr_alert("Data abort info:\n"); |
| |
| if (esr & ESR_ELx_ISV) { |
| pr_alert(" Access size = %u byte(s)\n", |
| 1U << ((esr & ESR_ELx_SAS) >> ESR_ELx_SAS_SHIFT)); |
| pr_alert(" SSE = %lu, SRT = %lu\n", |
| (esr & ESR_ELx_SSE) >> ESR_ELx_SSE_SHIFT, |
| (esr & ESR_ELx_SRT_MASK) >> ESR_ELx_SRT_SHIFT); |
| pr_alert(" SF = %lu, AR = %lu\n", |
| (esr & ESR_ELx_SF) >> ESR_ELx_SF_SHIFT, |
| (esr & ESR_ELx_AR) >> ESR_ELx_AR_SHIFT); |
| } else { |
| pr_alert(" ISV = 0, ISS = 0x%08lx\n", esr & ESR_ELx_ISS_MASK); |
| } |
| |
| pr_alert(" CM = %lu, WnR = %lu\n", |
| (esr & ESR_ELx_CM) >> ESR_ELx_CM_SHIFT, |
| (esr & ESR_ELx_WNR) >> ESR_ELx_WNR_SHIFT); |
| } |
| |
| static void mem_abort_decode(unsigned int esr) |
| { |
| pr_alert("Mem abort info:\n"); |
| |
| pr_alert(" ESR = 0x%08x\n", esr); |
| pr_alert(" EC = 0x%02lx: %s, IL = %u bits\n", |
| ESR_ELx_EC(esr), esr_get_class_string(esr), |
| (esr & ESR_ELx_IL) ? 32 : 16); |
| pr_alert(" SET = %lu, FnV = %lu\n", |
| (esr & ESR_ELx_SET_MASK) >> ESR_ELx_SET_SHIFT, |
| (esr & ESR_ELx_FnV) >> ESR_ELx_FnV_SHIFT); |
| pr_alert(" EA = %lu, S1PTW = %lu\n", |
| (esr & ESR_ELx_EA) >> ESR_ELx_EA_SHIFT, |
| (esr & ESR_ELx_S1PTW) >> ESR_ELx_S1PTW_SHIFT); |
| pr_alert(" FSC = 0x%02x: %s\n", (esr & ESR_ELx_FSC), |
| esr_to_fault_info(esr)->name); |
| |
| if (esr_is_data_abort(esr)) |
| data_abort_decode(esr); |
| } |
| |
| static inline unsigned long mm_to_pgd_phys(struct mm_struct *mm) |
| { |
| /* Either init_pg_dir or swapper_pg_dir */ |
| if (mm == &init_mm) |
| return __pa_symbol(mm->pgd); |
| |
| return (unsigned long)virt_to_phys(mm->pgd); |
| } |
| |
| /* |
| * Dump out the page tables associated with 'addr' in the currently active mm. |
| */ |
| static void show_pte(unsigned long addr) |
| { |
| struct mm_struct *mm; |
| pgd_t *pgdp; |
| pgd_t pgd; |
| |
| if (is_ttbr0_addr(addr)) { |
| /* TTBR0 */ |
| mm = current->active_mm; |
| if (mm == &init_mm) { |
| pr_alert("[%016lx] user address but active_mm is swapper\n", |
| addr); |
| return; |
| } |
| } else if (is_ttbr1_addr(addr)) { |
| /* TTBR1 */ |
| mm = &init_mm; |
| } else { |
| pr_alert("[%016lx] address between user and kernel address ranges\n", |
| addr); |
| return; |
| } |
| |
| pr_alert("%s pgtable: %luk pages, %llu-bit VAs, pgdp=%016lx\n", |
| mm == &init_mm ? "swapper" : "user", PAGE_SIZE / SZ_1K, |
| vabits_actual, mm_to_pgd_phys(mm)); |
| pgdp = pgd_offset(mm, addr); |
| pgd = READ_ONCE(*pgdp); |
| pr_alert("[%016lx] pgd=%016llx", addr, pgd_val(pgd)); |
| |
| do { |
| p4d_t *p4dp, p4d; |
| pud_t *pudp, pud; |
| pmd_t *pmdp, pmd; |
| pte_t *ptep, pte; |
| |
| if (pgd_none(pgd) || pgd_bad(pgd)) |
| break; |
| |
| p4dp = p4d_offset(pgdp, addr); |
| p4d = READ_ONCE(*p4dp); |
| pr_cont(", p4d=%016llx", p4d_val(p4d)); |
| if (p4d_none(p4d) || p4d_bad(p4d)) |
| break; |
| |
| pudp = pud_offset(p4dp, addr); |
| pud = READ_ONCE(*pudp); |
| pr_cont(", pud=%016llx", pud_val(pud)); |
| if (pud_none(pud) || pud_bad(pud)) |
| break; |
| |
| pmdp = pmd_offset(pudp, addr); |
| pmd = READ_ONCE(*pmdp); |
| pr_cont(", pmd=%016llx", pmd_val(pmd)); |
| if (pmd_none(pmd) || pmd_bad(pmd)) |
| break; |
| |
| ptep = pte_offset_map(pmdp, addr); |
| pte = READ_ONCE(*ptep); |
| pr_cont(", pte=%016llx", pte_val(pte)); |
| pte_unmap(ptep); |
| } while(0); |
| |
| pr_cont("\n"); |
| } |
| |
| /* |
| * This function sets the access flags (dirty, accessed), as well as write |
| * permission, and only to a more permissive setting. |
| * |
| * It needs to cope with hardware update of the accessed/dirty state by other |
| * agents in the system and can safely skip the __sync_icache_dcache() call as, |
| * like set_pte_at(), the PTE is never changed from no-exec to exec here. |
| * |
| * Returns whether or not the PTE actually changed. |
| */ |
| int ptep_set_access_flags(struct vm_area_struct *vma, |
| unsigned long address, pte_t *ptep, |
| pte_t entry, int dirty) |
| { |
| pteval_t old_pteval, pteval; |
| pte_t pte = READ_ONCE(*ptep); |
| |
| if (pte_same(pte, entry)) |
| return 0; |
| |
| /* only preserve the access flags and write permission */ |
| pte_val(entry) &= PTE_RDONLY | PTE_AF | PTE_WRITE | PTE_DIRTY; |
| |
| /* |
| * Setting the flags must be done atomically to avoid racing with the |
| * hardware update of the access/dirty state. The PTE_RDONLY bit must |
| * be set to the most permissive (lowest value) of *ptep and entry |
| * (calculated as: a & b == ~(~a | ~b)). |
| */ |
| pte_val(entry) ^= PTE_RDONLY; |
| pteval = pte_val(pte); |
| do { |
| old_pteval = pteval; |
| pteval ^= PTE_RDONLY; |
| pteval |= pte_val(entry); |
| pteval ^= PTE_RDONLY; |
| pteval = cmpxchg_relaxed(&pte_val(*ptep), old_pteval, pteval); |
| } while (pteval != old_pteval); |
| |
| /* Invalidate a stale read-only entry */ |
| if (dirty) |
| flush_tlb_page(vma, address); |
| return 1; |
| } |
| |
| static bool is_el1_instruction_abort(unsigned int esr) |
| { |
| return ESR_ELx_EC(esr) == ESR_ELx_EC_IABT_CUR; |
| } |
| |
| static bool is_el1_data_abort(unsigned int esr) |
| { |
| return ESR_ELx_EC(esr) == ESR_ELx_EC_DABT_CUR; |
| } |
| |
| static inline bool is_el1_permission_fault(unsigned long addr, unsigned int esr, |
| struct pt_regs *regs) |
| { |
| unsigned int fsc_type = esr & ESR_ELx_FSC_TYPE; |
| |
| if (!is_el1_data_abort(esr) && !is_el1_instruction_abort(esr)) |
| return false; |
| |
| if (fsc_type == ESR_ELx_FSC_PERM) |
| return true; |
| |
| if (is_ttbr0_addr(addr) && system_uses_ttbr0_pan()) |
| return fsc_type == ESR_ELx_FSC_FAULT && |
| (regs->pstate & PSR_PAN_BIT); |
| |
| return false; |
| } |
| |
| static bool __kprobes is_spurious_el1_translation_fault(unsigned long addr, |
| unsigned int esr, |
| struct pt_regs *regs) |
| { |
| unsigned long flags; |
| u64 par, dfsc; |
| |
| if (!is_el1_data_abort(esr) || |
| (esr & ESR_ELx_FSC_TYPE) != ESR_ELx_FSC_FAULT) |
| return false; |
| |
| local_irq_save(flags); |
| asm volatile("at s1e1r, %0" :: "r" (addr)); |
| isb(); |
| par = read_sysreg_par(); |
| local_irq_restore(flags); |
| |
| /* |
| * If we now have a valid translation, treat the translation fault as |
| * spurious. |
| */ |
| if (!(par & SYS_PAR_EL1_F)) |
| return true; |
| |
| /* |
| * If we got a different type of fault from the AT instruction, |
| * treat the translation fault as spurious. |
| */ |
| dfsc = FIELD_GET(SYS_PAR_EL1_FST, par); |
| return (dfsc & ESR_ELx_FSC_TYPE) != ESR_ELx_FSC_FAULT; |
| } |
| |
| static void die_kernel_fault(const char *msg, unsigned long addr, |
| unsigned int esr, struct pt_regs *regs) |
| { |
| bust_spinlocks(1); |
| |
| pr_alert("Unable to handle kernel %s at virtual address %016lx\n", msg, |
| addr); |
| |
| mem_abort_decode(esr); |
| |
| show_pte(addr); |
| die("Oops", regs, esr); |
| bust_spinlocks(0); |
| do_exit(SIGKILL); |
| } |
| |
| #ifdef CONFIG_KASAN_HW_TAGS |
| static void report_tag_fault(unsigned long addr, unsigned int esr, |
| struct pt_regs *regs) |
| { |
| static bool reported; |
| bool is_write; |
| |
| if (READ_ONCE(reported)) |
| return; |
| |
| /* |
| * This is used for KASAN tests and assumes that no MTE faults |
| * happened before running the tests. |
| */ |
| if (mte_report_once()) |
| WRITE_ONCE(reported, true); |
| |
| /* |
| * SAS bits aren't set for all faults reported in EL1, so we can't |
| * find out access size. |
| */ |
| is_write = !!(esr & ESR_ELx_WNR); |
| kasan_report(addr, 0, is_write, regs->pc); |
| } |
| #else |
| /* Tag faults aren't enabled without CONFIG_KASAN_HW_TAGS. */ |
| static inline void report_tag_fault(unsigned long addr, unsigned int esr, |
| struct pt_regs *regs) { } |
| #endif |
| |
| static void do_tag_recovery(unsigned long addr, unsigned int esr, |
| struct pt_regs *regs) |
| { |
| |
| report_tag_fault(addr, esr, regs); |
| |
| /* |
| * Disable MTE Tag Checking on the local CPU for the current EL. |
| * It will be done lazily on the other CPUs when they will hit a |
| * tag fault. |
| */ |
| sysreg_clear_set(sctlr_el1, SCTLR_ELx_TCF_MASK, SCTLR_ELx_TCF_NONE); |
| isb(); |
| } |
| |
| static bool is_el1_mte_sync_tag_check_fault(unsigned int esr) |
| { |
| unsigned int fsc = esr & ESR_ELx_FSC; |
| |
| if (!is_el1_data_abort(esr)) |
| return false; |
| |
| if (fsc == ESR_ELx_FSC_MTE) |
| return true; |
| |
| return false; |
| } |
| |
| static void __do_kernel_fault(unsigned long addr, unsigned int esr, |
| struct pt_regs *regs) |
| { |
| const char *msg; |
| |
| /* |
| * Are we prepared to handle this kernel fault? |
| * We are almost certainly not prepared to handle instruction faults. |
| */ |
| if (!is_el1_instruction_abort(esr) && fixup_exception(regs)) |
| return; |
| |
| if (WARN_RATELIMIT(is_spurious_el1_translation_fault(addr, esr, regs), |
| "Ignoring spurious kernel translation fault at virtual address %016lx\n", addr)) |
| return; |
| |
| if (is_el1_mte_sync_tag_check_fault(esr)) { |
| do_tag_recovery(addr, esr, regs); |
| |
| return; |
| } |
| |
| if (is_el1_permission_fault(addr, esr, regs)) { |
| if (esr & ESR_ELx_WNR) |
| msg = "write to read-only memory"; |
| else if (is_el1_instruction_abort(esr)) |
| msg = "execute from non-executable memory"; |
| else |
| msg = "read from unreadable memory"; |
| } else if (addr < PAGE_SIZE) { |
| msg = "NULL pointer dereference"; |
| } else { |
| if (kfence_handle_page_fault(addr, esr & ESR_ELx_WNR, regs)) |
| return; |
| |
| msg = "paging request"; |
| } |
| |
| die_kernel_fault(msg, addr, esr, regs); |
| } |
| |
| static void set_thread_esr(unsigned long address, unsigned int esr) |
| { |
| current->thread.fault_address = address; |
| |
| /* |
| * If the faulting address is in the kernel, we must sanitize the ESR. |
| * From userspace's point of view, kernel-only mappings don't exist |
| * at all, so we report them as level 0 translation faults. |
| * (This is not quite the way that "no mapping there at all" behaves: |
| * an alignment fault not caused by the memory type would take |
| * precedence over translation fault for a real access to empty |
| * space. Unfortunately we can't easily distinguish "alignment fault |
| * not caused by memory type" from "alignment fault caused by memory |
| * type", so we ignore this wrinkle and just return the translation |
| * fault.) |
| */ |
| if (!is_ttbr0_addr(current->thread.fault_address)) { |
| switch (ESR_ELx_EC(esr)) { |
| case ESR_ELx_EC_DABT_LOW: |
| /* |
| * These bits provide only information about the |
| * faulting instruction, which userspace knows already. |
| * We explicitly clear bits which are architecturally |
| * RES0 in case they are given meanings in future. |
| * We always report the ESR as if the fault was taken |
| * to EL1 and so ISV and the bits in ISS[23:14] are |
| * clear. (In fact it always will be a fault to EL1.) |
| */ |
| esr &= ESR_ELx_EC_MASK | ESR_ELx_IL | |
| ESR_ELx_CM | ESR_ELx_WNR; |
| esr |= ESR_ELx_FSC_FAULT; |
| break; |
| case ESR_ELx_EC_IABT_LOW: |
| /* |
| * Claim a level 0 translation fault. |
| * All other bits are architecturally RES0 for faults |
| * reported with that DFSC value, so we clear them. |
| */ |
| esr &= ESR_ELx_EC_MASK | ESR_ELx_IL; |
| esr |= ESR_ELx_FSC_FAULT; |
| break; |
| default: |
| /* |
| * This should never happen (entry.S only brings us |
| * into this code for insn and data aborts from a lower |
| * exception level). Fail safe by not providing an ESR |
| * context record at all. |
| */ |
| WARN(1, "ESR 0x%x is not DABT or IABT from EL0\n", esr); |
| esr = 0; |
| break; |
| } |
| } |
| |
| current->thread.fault_code = esr; |
| } |
| |
| static void do_bad_area(unsigned long far, unsigned int esr, |
| struct pt_regs *regs) |
| { |
| unsigned long addr = untagged_addr(far); |
| |
| /* |
| * If we are in kernel mode at this point, we have no context to |
| * handle this fault with. |
| */ |
| if (user_mode(regs)) { |
| const struct fault_info *inf = esr_to_fault_info(esr); |
| |
| set_thread_esr(addr, esr); |
| arm64_force_sig_fault(inf->sig, inf->code, far, inf->name); |
| } else { |
| __do_kernel_fault(addr, esr, regs); |
| } |
| } |
| |
| #define VM_FAULT_BADMAP 0x010000 |
| #define VM_FAULT_BADACCESS 0x020000 |
| |
| static vm_fault_t __do_page_fault(struct mm_struct *mm, unsigned long addr, |
| unsigned int mm_flags, unsigned long vm_flags, |
| struct pt_regs *regs) |
| { |
| struct vm_area_struct *vma = find_vma(mm, addr); |
| |
| if (unlikely(!vma)) |
| return VM_FAULT_BADMAP; |
| |
| /* |
| * Ok, we have a good vm_area for this memory access, so we can handle |
| * it. |
| */ |
| if (unlikely(vma->vm_start > addr)) { |
| if (!(vma->vm_flags & VM_GROWSDOWN)) |
| return VM_FAULT_BADMAP; |
| if (expand_stack(vma, addr)) |
| return VM_FAULT_BADMAP; |
| } |
| |
| /* |
| * Check that the permissions on the VMA allow for the fault which |
| * occurred. |
| */ |
| if (!(vma->vm_flags & vm_flags)) |
| return VM_FAULT_BADACCESS; |
| return handle_mm_fault(vma, addr, mm_flags, regs); |
| } |
| |
| static bool is_el0_instruction_abort(unsigned int esr) |
| { |
| return ESR_ELx_EC(esr) == ESR_ELx_EC_IABT_LOW; |
| } |
| |
| /* |
| * Note: not valid for EL1 DC IVAC, but we never use that such that it |
| * should fault. EL0 cannot issue DC IVAC (undef). |
| */ |
| static bool is_write_abort(unsigned int esr) |
| { |
| return (esr & ESR_ELx_WNR) && !(esr & ESR_ELx_CM); |
| } |
| |
| static int __kprobes do_page_fault(unsigned long far, unsigned int esr, |
| struct pt_regs *regs) |
| { |
| const struct fault_info *inf; |
| struct mm_struct *mm = current->mm; |
| vm_fault_t fault; |
| unsigned long vm_flags; |
| unsigned int mm_flags = FAULT_FLAG_DEFAULT; |
| unsigned long addr = untagged_addr(far); |
| |
| if (kprobe_page_fault(regs, esr)) |
| return 0; |
| |
| /* |
| * If we're in an interrupt or have no user context, we must not take |
| * the fault. |
| */ |
| if (faulthandler_disabled() || !mm) |
| goto no_context; |
| |
| if (user_mode(regs)) |
| mm_flags |= FAULT_FLAG_USER; |
| |
| /* |
| * vm_flags tells us what bits we must have in vma->vm_flags |
| * for the fault to be benign, __do_page_fault() would check |
| * vma->vm_flags & vm_flags and returns an error if the |
| * intersection is empty |
| */ |
| if (is_el0_instruction_abort(esr)) { |
| /* It was exec fault */ |
| vm_flags = VM_EXEC; |
| mm_flags |= FAULT_FLAG_INSTRUCTION; |
| } else if (is_write_abort(esr)) { |
| /* It was write fault */ |
| vm_flags = VM_WRITE; |
| mm_flags |= FAULT_FLAG_WRITE; |
| } else { |
| /* It was read fault */ |
| vm_flags = VM_READ; |
| /* Write implies read */ |
| vm_flags |= VM_WRITE; |
| /* If EPAN is absent then exec implies read */ |
| if (!cpus_have_const_cap(ARM64_HAS_EPAN)) |
| vm_flags |= VM_EXEC; |
| } |
| |
| if (is_ttbr0_addr(addr) && is_el1_permission_fault(addr, esr, regs)) { |
| if (is_el1_instruction_abort(esr)) |
| die_kernel_fault("execution of user memory", |
| addr, esr, regs); |
| |
| if (!search_exception_tables(regs->pc)) |
| die_kernel_fault("access to user memory outside uaccess routines", |
| addr, esr, regs); |
| } |
| |
| perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS, 1, regs, addr); |
| |
| /* |
| * As per x86, we may deadlock here. However, since the kernel only |
| * validly references user space from well defined areas of the code, |
| * we can bug out early if this is from code which shouldn't. |
| */ |
| if (!mmap_read_trylock(mm)) { |
| if (!user_mode(regs) && !search_exception_tables(regs->pc)) |
| goto no_context; |
| retry: |
| mmap_read_lock(mm); |
| } else { |
| /* |
| * The above mmap_read_trylock() might have succeeded in which |
| * case, we'll have missed the might_sleep() from down_read(). |
| */ |
| might_sleep(); |
| #ifdef CONFIG_DEBUG_VM |
| if (!user_mode(regs) && !search_exception_tables(regs->pc)) { |
| mmap_read_unlock(mm); |
| goto no_context; |
| } |
| #endif |
| } |
| |
| fault = __do_page_fault(mm, addr, mm_flags, vm_flags, regs); |
| |
| /* Quick path to respond to signals */ |
| if (fault_signal_pending(fault, regs)) { |
| if (!user_mode(regs)) |
| goto no_context; |
| return 0; |
| } |
| |
| if (fault & VM_FAULT_RETRY) { |
| if (mm_flags & FAULT_FLAG_ALLOW_RETRY) { |
| mm_flags |= FAULT_FLAG_TRIED; |
| goto retry; |
| } |
| } |
| mmap_read_unlock(mm); |
| |
| /* |
| * Handle the "normal" (no error) case first. |
| */ |
| if (likely(!(fault & (VM_FAULT_ERROR | VM_FAULT_BADMAP | |
| VM_FAULT_BADACCESS)))) |
| return 0; |
| |
| /* |
| * If we are in kernel mode at this point, we have no context to |
| * handle this fault with. |
| */ |
| if (!user_mode(regs)) |
| goto no_context; |
| |
| if (fault & VM_FAULT_OOM) { |
| /* |
| * We ran out of memory, call the OOM killer, and return to |
| * userspace (which will retry the fault, or kill us if we got |
| * oom-killed). |
| */ |
| pagefault_out_of_memory(); |
| return 0; |
| } |
| |
| inf = esr_to_fault_info(esr); |
| set_thread_esr(addr, esr); |
| if (fault & VM_FAULT_SIGBUS) { |
| /* |
| * We had some memory, but were unable to successfully fix up |
| * this page fault. |
| */ |
| arm64_force_sig_fault(SIGBUS, BUS_ADRERR, far, inf->name); |
| } else if (fault & (VM_FAULT_HWPOISON_LARGE | VM_FAULT_HWPOISON)) { |
| unsigned int lsb; |
| |
| lsb = PAGE_SHIFT; |
| if (fault & VM_FAULT_HWPOISON_LARGE) |
| lsb = hstate_index_to_shift(VM_FAULT_GET_HINDEX(fault)); |
| |
| arm64_force_sig_mceerr(BUS_MCEERR_AR, far, lsb, inf->name); |
| } else { |
| /* |
| * Something tried to access memory that isn't in our memory |
| * map. |
| */ |
| arm64_force_sig_fault(SIGSEGV, |
| fault == VM_FAULT_BADACCESS ? SEGV_ACCERR : SEGV_MAPERR, |
| far, inf->name); |
| } |
| |
| return 0; |
| |
| no_context: |
| __do_kernel_fault(addr, esr, regs); |
| return 0; |
| } |
| |
| static int __kprobes do_translation_fault(unsigned long far, |
| unsigned int esr, |
| struct pt_regs *regs) |
| { |
| unsigned long addr = untagged_addr(far); |
| |
| if (is_ttbr0_addr(addr)) |
| return do_page_fault(far, esr, regs); |
| |
| do_bad_area(far, esr, regs); |
| return 0; |
| } |
| |
| static int do_alignment_fault(unsigned long far, unsigned int esr, |
| struct pt_regs *regs) |
| { |
| do_bad_area(far, esr, regs); |
| return 0; |
| } |
| |
| static int do_bad(unsigned long far, unsigned int esr, struct pt_regs *regs) |
| { |
| return 1; /* "fault" */ |
| } |
| |
| static int do_sea(unsigned long far, unsigned int esr, struct pt_regs *regs) |
| { |
| const struct fault_info *inf; |
| unsigned long siaddr; |
| |
| inf = esr_to_fault_info(esr); |
| |
| if (user_mode(regs) && apei_claim_sea(regs) == 0) { |
| /* |
| * APEI claimed this as a firmware-first notification. |
| * Some processing deferred to task_work before ret_to_user(). |
| */ |
| return 0; |
| } |
| |
| if (esr & ESR_ELx_FnV) { |
| siaddr = 0; |
| } else { |
| /* |
| * The architecture specifies that the tag bits of FAR_EL1 are |
| * UNKNOWN for synchronous external aborts. Mask them out now |
| * so that userspace doesn't see them. |
| */ |
| siaddr = untagged_addr(far); |
| } |
| arm64_notify_die(inf->name, regs, inf->sig, inf->code, siaddr, esr); |
| |
| return 0; |
| } |
| |
| static int do_tag_check_fault(unsigned long far, unsigned int esr, |
| struct pt_regs *regs) |
| { |
| /* |
| * The architecture specifies that bits 63:60 of FAR_EL1 are UNKNOWN |
| * for tag check faults. Set them to corresponding bits in the untagged |
| * address. |
| */ |
| far = (__untagged_addr(far) & ~MTE_TAG_MASK) | (far & MTE_TAG_MASK); |
| do_bad_area(far, esr, regs); |
| return 0; |
| } |
| |
| static const struct fault_info fault_info[] = { |
| { do_bad, SIGKILL, SI_KERNEL, "ttbr address size fault" }, |
| { do_bad, SIGKILL, SI_KERNEL, "level 1 address size fault" }, |
| { do_bad, SIGKILL, SI_KERNEL, "level 2 address size fault" }, |
| { do_bad, SIGKILL, SI_KERNEL, "level 3 address size fault" }, |
| { do_translation_fault, SIGSEGV, SEGV_MAPERR, "level 0 translation fault" }, |
| { do_translation_fault, SIGSEGV, SEGV_MAPERR, "level 1 translation fault" }, |
| { do_translation_fault, SIGSEGV, SEGV_MAPERR, "level 2 translation fault" }, |
| { do_translation_fault, SIGSEGV, SEGV_MAPERR, "level 3 translation fault" }, |
| { do_bad, SIGKILL, SI_KERNEL, "unknown 8" }, |
| { do_page_fault, SIGSEGV, SEGV_ACCERR, "level 1 access flag fault" }, |
| { do_page_fault, SIGSEGV, SEGV_ACCERR, "level 2 access flag fault" }, |
| { do_page_fault, SIGSEGV, SEGV_ACCERR, "level 3 access flag fault" }, |
| { do_bad, SIGKILL, SI_KERNEL, "unknown 12" }, |
| { do_page_fault, SIGSEGV, SEGV_ACCERR, "level 1 permission fault" }, |
| { do_page_fault, SIGSEGV, SEGV_ACCERR, "level 2 permission fault" }, |
| { do_page_fault, SIGSEGV, SEGV_ACCERR, "level 3 permission fault" }, |
| { do_sea, SIGBUS, BUS_OBJERR, "synchronous external abort" }, |
| { do_tag_check_fault, SIGSEGV, SEGV_MTESERR, "synchronous tag check fault" }, |
| { do_bad, SIGKILL, SI_KERNEL, "unknown 18" }, |
| { do_bad, SIGKILL, SI_KERNEL, "unknown 19" }, |
| { do_sea, SIGKILL, SI_KERNEL, "level 0 (translation table walk)" }, |
| { do_sea, SIGKILL, SI_KERNEL, "level 1 (translation table walk)" }, |
| { do_sea, SIGKILL, SI_KERNEL, "level 2 (translation table walk)" }, |
| { do_sea, SIGKILL, SI_KERNEL, "level 3 (translation table walk)" }, |
| { do_sea, SIGBUS, BUS_OBJERR, "synchronous parity or ECC error" }, // Reserved when RAS is implemented |
| { do_bad, SIGKILL, SI_KERNEL, "unknown 25" }, |
| { do_bad, SIGKILL, SI_KERNEL, "unknown 26" }, |
| { do_bad, SIGKILL, SI_KERNEL, "unknown 27" }, |
| { do_sea, SIGKILL, SI_KERNEL, "level 0 synchronous parity error (translation table walk)" }, // Reserved when RAS is implemented |
| { do_sea, SIGKILL, SI_KERNEL, "level 1 synchronous parity error (translation table walk)" }, // Reserved when RAS is implemented |
| { do_sea, SIGKILL, SI_KERNEL, "level 2 synchronous parity error (translation table walk)" }, // Reserved when RAS is implemented |
| { do_sea, SIGKILL, SI_KERNEL, "level 3 synchronous parity error (translation table walk)" }, // Reserved when RAS is implemented |
| { do_bad, SIGKILL, SI_KERNEL, "unknown 32" }, |
| { do_alignment_fault, SIGBUS, BUS_ADRALN, "alignment fault" }, |
| { do_bad, SIGKILL, SI_KERNEL, "unknown 34" }, |
| { do_bad, SIGKILL, SI_KERNEL, "unknown 35" }, |
| { do_bad, SIGKILL, SI_KERNEL, "unknown 36" }, |
| { do_bad, SIGKILL, SI_KERNEL, "unknown 37" }, |
| { do_bad, SIGKILL, SI_KERNEL, "unknown 38" }, |
| { do_bad, SIGKILL, SI_KERNEL, "unknown 39" }, |
| { do_bad, SIGKILL, SI_KERNEL, "unknown 40" }, |
| { do_bad, SIGKILL, SI_KERNEL, "unknown 41" }, |
| { do_bad, SIGKILL, SI_KERNEL, "unknown 42" }, |
| { do_bad, SIGKILL, SI_KERNEL, "unknown 43" }, |
| { do_bad, SIGKILL, SI_KERNEL, "unknown 44" }, |
| { do_bad, SIGKILL, SI_KERNEL, "unknown 45" }, |
| { do_bad, SIGKILL, SI_KERNEL, "unknown 46" }, |
| { do_bad, SIGKILL, SI_KERNEL, "unknown 47" }, |
| { do_bad, SIGKILL, SI_KERNEL, "TLB conflict abort" }, |
| { do_bad, SIGKILL, SI_KERNEL, "Unsupported atomic hardware update fault" }, |
| { do_bad, SIGKILL, SI_KERNEL, "unknown 50" }, |
| { do_bad, SIGKILL, SI_KERNEL, "unknown 51" }, |
| { do_bad, SIGKILL, SI_KERNEL, "implementation fault (lockdown abort)" }, |
| { do_bad, SIGBUS, BUS_OBJERR, "implementation fault (unsupported exclusive)" }, |
| { do_bad, SIGKILL, SI_KERNEL, "unknown 54" }, |
| { do_bad, SIGKILL, SI_KERNEL, "unknown 55" }, |
| { do_bad, SIGKILL, SI_KERNEL, "unknown 56" }, |
| { do_bad, SIGKILL, SI_KERNEL, "unknown 57" }, |
| { do_bad, SIGKILL, SI_KERNEL, "unknown 58" }, |
| { do_bad, SIGKILL, SI_KERNEL, "unknown 59" }, |
| { do_bad, SIGKILL, SI_KERNEL, "unknown 60" }, |
| { do_bad, SIGKILL, SI_KERNEL, "section domain fault" }, |
| { do_bad, SIGKILL, SI_KERNEL, "page domain fault" }, |
| { do_bad, SIGKILL, SI_KERNEL, "unknown 63" }, |
| }; |
| |
| void do_mem_abort(unsigned long far, unsigned int esr, struct pt_regs *regs) |
| { |
| const struct fault_info *inf = esr_to_fault_info(esr); |
| unsigned long addr = untagged_addr(far); |
| |
| if (!inf->fn(far, esr, regs)) |
| return; |
| |
| if (!user_mode(regs)) { |
| pr_alert("Unhandled fault at 0x%016lx\n", addr); |
| mem_abort_decode(esr); |
| show_pte(addr); |
| } |
| |
| /* |
| * At this point we have an unrecognized fault type whose tag bits may |
| * have been defined as UNKNOWN. Therefore we only expose the untagged |
| * address to the signal handler. |
| */ |
| arm64_notify_die(inf->name, regs, inf->sig, inf->code, addr, esr); |
| } |
| NOKPROBE_SYMBOL(do_mem_abort); |
| |
| void do_sp_pc_abort(unsigned long addr, unsigned int esr, struct pt_regs *regs) |
| { |
| arm64_notify_die("SP/PC alignment exception", regs, SIGBUS, BUS_ADRALN, |
| addr, esr); |
| } |
| NOKPROBE_SYMBOL(do_sp_pc_abort); |
| |
| int __init early_brk64(unsigned long addr, unsigned int esr, |
| struct pt_regs *regs); |
| |
| /* |
| * __refdata because early_brk64 is __init, but the reference to it is |
| * clobbered at arch_initcall time. |
| * See traps.c and debug-monitors.c:debug_traps_init(). |
| */ |
| static struct fault_info __refdata debug_fault_info[] = { |
| { do_bad, SIGTRAP, TRAP_HWBKPT, "hardware breakpoint" }, |
| { do_bad, SIGTRAP, TRAP_HWBKPT, "hardware single-step" }, |
| { do_bad, SIGTRAP, TRAP_HWBKPT, "hardware watchpoint" }, |
| { do_bad, SIGKILL, SI_KERNEL, "unknown 3" }, |
| { do_bad, SIGTRAP, TRAP_BRKPT, "aarch32 BKPT" }, |
| { do_bad, SIGKILL, SI_KERNEL, "aarch32 vector catch" }, |
| { early_brk64, SIGTRAP, TRAP_BRKPT, "aarch64 BRK" }, |
| { do_bad, SIGKILL, SI_KERNEL, "unknown 7" }, |
| }; |
| |
| void __init hook_debug_fault_code(int nr, |
| int (*fn)(unsigned long, unsigned int, struct pt_regs *), |
| int sig, int code, const char *name) |
| { |
| BUG_ON(nr < 0 || nr >= ARRAY_SIZE(debug_fault_info)); |
| |
| debug_fault_info[nr].fn = fn; |
| debug_fault_info[nr].sig = sig; |
| debug_fault_info[nr].code = code; |
| debug_fault_info[nr].name = name; |
| } |
| |
| /* |
| * In debug exception context, we explicitly disable preemption despite |
| * having interrupts disabled. |
| * This serves two purposes: it makes it much less likely that we would |
| * accidentally schedule in exception context and it will force a warning |
| * if we somehow manage to schedule by accident. |
| */ |
| static void debug_exception_enter(struct pt_regs *regs) |
| { |
| preempt_disable(); |
| |
| /* This code is a bit fragile. Test it. */ |
| RCU_LOCKDEP_WARN(!rcu_is_watching(), "exception_enter didn't work"); |
| } |
| NOKPROBE_SYMBOL(debug_exception_enter); |
| |
| static void debug_exception_exit(struct pt_regs *regs) |
| { |
| preempt_enable_no_resched(); |
| } |
| NOKPROBE_SYMBOL(debug_exception_exit); |
| |
| void do_debug_exception(unsigned long addr_if_watchpoint, unsigned int esr, |
| struct pt_regs *regs) |
| { |
| const struct fault_info *inf = esr_to_debug_fault_info(esr); |
| unsigned long pc = instruction_pointer(regs); |
| |
| debug_exception_enter(regs); |
| |
| if (user_mode(regs) && !is_ttbr0_addr(pc)) |
| arm64_apply_bp_hardening(); |
| |
| if (inf->fn(addr_if_watchpoint, esr, regs)) { |
| arm64_notify_die(inf->name, regs, inf->sig, inf->code, pc, esr); |
| } |
| |
| debug_exception_exit(regs); |
| } |
| NOKPROBE_SYMBOL(do_debug_exception); |
| |
| /* |
| * Used during anonymous page fault handling. |
| */ |
| struct page *alloc_zeroed_user_highpage_movable(struct vm_area_struct *vma, |
| unsigned long vaddr) |
| { |
| gfp_t flags = GFP_HIGHUSER_MOVABLE | __GFP_ZERO; |
| |
| /* |
| * If the page is mapped with PROT_MTE, initialise the tags at the |
| * point of allocation and page zeroing as this is usually faster than |
| * separate DC ZVA and STGM. |
| */ |
| if (vma->vm_flags & VM_MTE) |
| flags |= __GFP_ZEROTAGS; |
| |
| return alloc_page_vma(flags, vma, vaddr); |
| } |
| |
| void tag_clear_highpage(struct page *page) |
| { |
| mte_zero_clear_page_tags(page_address(page)); |
| page_kasan_tag_reset(page); |
| set_bit(PG_mte_tagged, &page->flags); |
| } |