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-rw-r--r--arch/arm64/mm/fault.c855
1 files changed, 855 insertions, 0 deletions
diff --git a/arch/arm64/mm/fault.c b/arch/arm64/mm/fault.c
new file mode 100644
index 000000000..d8baedd16
--- /dev/null
+++ b/arch/arm64/mm/fault.c
@@ -0,0 +1,855 @@
+// 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/signal.h>
+#include <linux/mm.h>
+#include <linux/hardirq.h>
+#include <linux/init.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/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 addr, 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);
+
+ 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 inline bool is_el1_permission_fault(unsigned long addr, unsigned int esr,
+ struct pt_regs *regs)
+{
+ unsigned int ec = ESR_ELx_EC(esr);
+ unsigned int fsc_type = esr & ESR_ELx_FSC_TYPE;
+
+ if (ec != ESR_ELx_EC_DABT_CUR && ec != ESR_ELx_EC_IABT_CUR)
+ 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 (ESR_ELx_EC(esr) != ESR_ELx_EC_DABT_CUR ||
+ (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);
+ make_task_dead(SIGKILL);
+}
+
+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_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 {
+ 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 addr, unsigned int esr, struct pt_regs *regs)
+{
+ /*
+ * 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, (void __user *)addr,
+ inf->name);
+ } else {
+ __do_kernel_fault(addr, esr, regs);
+ }
+}
+
+#define VM_FAULT_BADMAP ((__force vm_fault_t)0x010000)
+#define VM_FAULT_BADACCESS ((__force vm_fault_t)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 & PAGE_MASK, 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 addr, 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 = VM_ACCESS_FLAGS;
+ unsigned int mm_flags = FAULT_FLAG_DEFAULT;
+
+ 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;
+
+ if (is_el0_instruction_abort(esr)) {
+ vm_flags = VM_EXEC;
+ mm_flags |= FAULT_FLAG_INSTRUCTION;
+ } else if (is_write_abort(esr)) {
+ vm_flags = VM_WRITE;
+ mm_flags |= FAULT_FLAG_WRITE;
+ }
+
+ if (is_ttbr0_addr(addr) && is_el1_permission_fault(addr, esr, regs)) {
+ /* regs->orig_addr_limit may be 0 if we entered from EL0 */
+ if (regs->orig_addr_limit == KERNEL_DS)
+ die_kernel_fault("access to user memory with fs=KERNEL_DS",
+ 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 down_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, (void __user *)addr,
+ 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, (void __user *)addr, 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,
+ (void __user *)addr,
+ inf->name);
+ }
+
+ return 0;
+
+no_context:
+ __do_kernel_fault(addr, esr, regs);
+ return 0;
+}
+
+static int __kprobes do_translation_fault(unsigned long addr,
+ unsigned int esr,
+ struct pt_regs *regs)
+{
+ if (is_ttbr0_addr(addr))
+ return do_page_fault(addr, esr, regs);
+
+ do_bad_area(addr, esr, regs);
+ return 0;
+}
+
+static int do_alignment_fault(unsigned long addr, unsigned int esr,
+ struct pt_regs *regs)
+{
+ do_bad_area(addr, esr, regs);
+ return 0;
+}
+
+static int do_bad(unsigned long addr, unsigned int esr, struct pt_regs *regs)
+{
+ return 1; /* "fault" */
+}
+
+static int do_sea(unsigned long addr, unsigned int esr, struct pt_regs *regs)
+{
+ const struct fault_info *inf;
+ void __user *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 = NULL;
+ else
+ siaddr = (void __user *)addr;
+ arm64_notify_die(inf->name, regs, inf->sig, inf->code, siaddr, esr);
+
+ return 0;
+}
+
+static int do_tag_check_fault(unsigned long addr, unsigned int esr,
+ struct pt_regs *regs)
+{
+ do_bad_area(addr, 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 addr, unsigned int esr, struct pt_regs *regs)
+{
+ const struct fault_info *inf = esr_to_fault_info(esr);
+
+ if (!inf->fn(addr, esr, regs))
+ return;
+
+ if (!user_mode(regs)) {
+ pr_alert("Unhandled fault at 0x%016lx\n", addr);
+ mem_abort_decode(esr);
+ show_pte(addr);
+ }
+
+ arm64_notify_die(inf->name, regs,
+ inf->sig, inf->code, (void __user *)addr, esr);
+}
+NOKPROBE_SYMBOL(do_mem_abort);
+
+void do_el0_irq_bp_hardening(void)
+{
+ /* PC has already been checked in entry.S */
+ arm64_apply_bp_hardening();
+}
+NOKPROBE_SYMBOL(do_el0_irq_bp_hardening);
+
+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, (void __user *)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);
+
+#ifdef CONFIG_ARM64_ERRATUM_1463225
+DECLARE_PER_CPU(int, __in_cortex_a76_erratum_1463225_wa);
+
+static int cortex_a76_erratum_1463225_debug_handler(struct pt_regs *regs)
+{
+ if (user_mode(regs))
+ return 0;
+
+ if (!__this_cpu_read(__in_cortex_a76_erratum_1463225_wa))
+ return 0;
+
+ /*
+ * We've taken a dummy step exception from the kernel to ensure
+ * that interrupts are re-enabled on the syscall path. Return back
+ * to cortex_a76_erratum_1463225_svc_handler() with debug exceptions
+ * masked so that we can safely restore the mdscr and get on with
+ * handling the syscall.
+ */
+ regs->pstate |= PSR_D_BIT;
+ return 1;
+}
+#else
+static int cortex_a76_erratum_1463225_debug_handler(struct pt_regs *regs)
+{
+ return 0;
+}
+#endif /* CONFIG_ARM64_ERRATUM_1463225 */
+NOKPROBE_SYMBOL(cortex_a76_erratum_1463225_debug_handler);
+
+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);
+
+ if (cortex_a76_erratum_1463225_debug_handler(regs))
+ return;
+
+ 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, (void __user *)pc, esr);
+ }
+
+ debug_exception_exit(regs);
+}
+NOKPROBE_SYMBOL(do_debug_exception);
generated by cgit v1.2.3 (git 2.39.1) at 2024-12-27 09:47:10 +0000