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WSL2-Linux-Kernel
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WSL2-Linux-Kernel/arch/arm64/mm/fault.c

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C
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/*
* Based on arch/arm/mm/fault.c
*
* Copyright (C) 1995 Linus Torvalds
* Copyright (C) 1995-2004 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/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/bug.h>
#include <asm/cmpxchg.h>
#include <asm/cpufeature.h>
#include <asm/exception.h>
#include <asm/debug-monitors.h>
#include <asm/esr.h>
#include <asm/sysreg.h>
#include <asm/system_misc.h>
#include <asm/pgtable.h>
#include <asm/tlbflush.h>
#include <acpi/ghes.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 inline const struct fault_info *esr_to_fault_info(unsigned int esr)
{
return fault_info + (esr & 63);
}
#ifdef CONFIG_KPROBES
static inline int notify_page_fault(struct pt_regs *regs, unsigned int esr)
{
int ret = 0;
/* kprobe_running() needs smp_processor_id() */
if (!user_mode(regs)) {
preempt_disable();
if (kprobe_running() && kprobe_fault_handler(regs, esr))
ret = 1;
preempt_enable();
}
return ret;
}
#else
static inline int notify_page_fault(struct pt_regs *regs, unsigned int esr)
{
return 0;
}
#endif
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(" Exception class = %s, IL = %u bits\n",
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);
}
/*
* Dump out the page tables associated with 'addr' in the currently active mm.
*/
void show_pte(unsigned long addr)
{
struct mm_struct *mm;
pgd_t *pgdp;
pgd_t pgd;
if (addr < TASK_SIZE) {
/* TTBR0 */
mm = current->active_mm;
if (mm == &init_mm) {
pr_alert("[%016lx] user address but active_mm is swapper\n",
addr);
return;
}
} else if (addr >= VA_START) {
/* TTBR1 */
mm = &init_mm;
} else {
pr_alert("[%016lx] address between user and kernel address ranges\n",
addr);
return;
}
pr_alert("%s pgtable: %luk pages, %u-bit VAs, pgdp = %p\n",
mm == &init_mm ? "swapper" : "user", PAGE_SIZE / SZ_1K,
VA_BITS, mm->pgd);
pgdp = pgd_offset(mm, addr);
pgd = READ_ONCE(*pgdp);
pr_alert("[%016lx] pgd=%016llx", addr, pgd_val(pgd));
do {
pud_t *pudp, pud;
pmd_t *pmdp, pmd;
pte_t *ptep, pte;
if (pgd_none(pgd) || pgd_bad(pgd))
break;
pudp = pud_offset(pgdp, 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);
flush_tlb_fix_spurious_fault(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_permission_fault(unsigned int esr, struct pt_regs *regs,
unsigned long addr)
{
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 (addr < TASK_SIZE && system_uses_ttbr0_pan())
return fsc_type == ESR_ELx_FSC_FAULT &&
(regs->pstate & PSR_PAN_BIT);
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;
bust_spinlocks(1);
if (is_permission_fault(esr, regs, addr)) {
if (esr & ESR_ELx_WNR)
msg = "write to read-only memory";
else
msg = "read from unreadable memory";
} else if (addr < PAGE_SIZE) {
msg = "NULL pointer dereference";
} else {
msg = "paging request";
}
pr_alert("Unable to handle kernel %s at virtual address %08lx\n", msg,
addr);
mem_abort_decode(esr);
show_pte(addr);
die("Oops", regs, esr);
bust_spinlocks(0);
do_exit(SIGKILL);
}
static void __do_user_fault(struct task_struct *tsk, unsigned long addr,
unsigned int esr, unsigned int sig, int code,
struct pt_regs *regs, int fault)
{
struct siginfo si;
const struct fault_info *inf;
unsigned int lsb = 0;
if (unhandled_signal(tsk, sig) && show_unhandled_signals_ratelimited()) {
inf = esr_to_fault_info(esr);
pr_info("%s[%d]: unhandled %s (%d) at 0x%08lx, esr 0x%03x",
tsk->comm, task_pid_nr(tsk), inf->name, sig,
addr, esr);
print_vma_addr(KERN_CONT ", in ", regs->pc);
pr_cont("\n");
__show_regs(regs);
}
tsk->thread.fault_address = addr;
tsk->thread.fault_code = esr;
si.si_signo = sig;
si.si_errno = 0;
si.si_code = code;
si.si_addr = (void __user *)addr;
/*
* Either small page or large page may be poisoned.
* In other words, VM_FAULT_HWPOISON_LARGE and
* VM_FAULT_HWPOISON are mutually exclusive.
*/
if (fault & VM_FAULT_HWPOISON_LARGE)
lsb = hstate_index_to_shift(VM_FAULT_GET_HINDEX(fault));
else if (fault & VM_FAULT_HWPOISON)
lsb = PAGE_SHIFT;
si.si_addr_lsb = lsb;
force_sig_info(sig, &si, tsk);
}
static void do_bad_area(unsigned long addr, unsigned int esr, struct pt_regs *regs)
{
struct task_struct *tsk = current;
const struct fault_info *inf;
/*
* If we are in kernel mode at this point, we have no context to
* handle this fault with.
*/
if (user_mode(regs)) {
inf = esr_to_fault_info(esr);
__do_user_fault(tsk, addr, esr, inf->sig, inf->code, regs, 0);
} else
__do_kernel_fault(addr, esr, regs);
}
#define VM_FAULT_BADMAP 0x010000
#define VM_FAULT_BADACCESS 0x020000
static int __do_page_fault(struct mm_struct *mm, unsigned long addr,
unsigned int mm_flags, unsigned long vm_flags,
struct task_struct *tsk)
{
struct vm_area_struct *vma;
int fault;
vma = find_vma(mm, addr);
fault = VM_FAULT_BADMAP;
if (unlikely(!vma))
goto out;
if (unlikely(vma->vm_start > addr))
goto check_stack;
/*
* Ok, we have a good vm_area for this memory access, so we can handle
* it.
*/
good_area:
/*
* Check that the permissions on the VMA allow for the fault which
* occurred.
*/
if (!(vma->vm_flags & vm_flags)) {
fault = VM_FAULT_BADACCESS;
goto out;
}
return handle_mm_fault(vma, addr & PAGE_MASK, mm_flags);
check_stack:
if (vma->vm_flags & VM_GROWSDOWN && !expand_stack(vma, addr))
goto good_area;
out:
return fault;
}
static bool is_el0_instruction_abort(unsigned int esr)
{
return ESR_ELx_EC(esr) == ESR_ELx_EC_IABT_LOW;
}
static int __kprobes do_page_fault(unsigned long addr, unsigned int esr,
struct pt_regs *regs)
{
struct task_struct *tsk;
struct mm_struct *mm;
int fault, sig, code, major = 0;
unsigned long vm_flags = VM_READ | VM_WRITE;
unsigned int mm_flags = FAULT_FLAG_ALLOW_RETRY | FAULT_FLAG_KILLABLE;
if (notify_page_fault(regs, esr))
return 0;
tsk = current;
mm = tsk->mm;
/*
* 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;
} else if ((esr & ESR_ELx_WNR) && !(esr & ESR_ELx_CM)) {
vm_flags = VM_WRITE;
mm_flags |= FAULT_FLAG_WRITE;
}
if (addr < TASK_SIZE && is_permission_fault(esr, regs, addr)) {
/* regs->orig_addr_limit may be 0 if we entered from EL0 */
if (regs->orig_addr_limit == KERNEL_DS)
die("Accessing user space memory with fs=KERNEL_DS", regs, esr);
if (is_el1_instruction_abort(esr))
die("Attempting to execute userspace memory", regs, esr);
if (!search_exception_tables(regs->pc))
die("Accessing user space memory outside uaccess.h routines", regs, esr);
}
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 (!down_read_trylock(&mm->mmap_sem)) {
if (!user_mode(regs) && !search_exception_tables(regs->pc))
goto no_context;
retry:
down_read(&mm->mmap_sem);
} 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))
goto no_context;
#endif
}
fault = __do_page_fault(mm, addr, mm_flags, vm_flags, tsk);
major |= fault & VM_FAULT_MAJOR;
if (fault & VM_FAULT_RETRY) {
/*
* If we need to retry but a fatal signal is pending,
* handle the signal first. We do not need to release
* the mmap_sem because it would already be released
* in __lock_page_or_retry in mm/filemap.c.
*/
if (fatal_signal_pending(current)) {
if (!user_mode(regs))
goto no_context;
return 0;
}
/*
* Clear FAULT_FLAG_ALLOW_RETRY to avoid any risk of
* starvation.
*/
if (mm_flags & FAULT_FLAG_ALLOW_RETRY) {
mm_flags &= ~FAULT_FLAG_ALLOW_RETRY;
mm_flags |= FAULT_FLAG_TRIED;
goto retry;
}
}
up_read(&mm->mmap_sem);
/*
* Handle the "normal" (no error) case first.
*/
if (likely(!(fault & (VM_FAULT_ERROR | VM_FAULT_BADMAP |
VM_FAULT_BADACCESS)))) {
/*
* Major/minor page fault accounting is only done
* once. If we go through a retry, it is extremely
* likely that the page will be found in page cache at
* that point.
*/
if (major) {
tsk->maj_flt++;
perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS_MAJ, 1, regs,
addr);
} else {
tsk->min_flt++;
perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS_MIN, 1, regs,
addr);
}
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;
}
if (fault & VM_FAULT_SIGBUS) {
/*
* We had some memory, but were unable to successfully fix up
* this page fault.
*/
sig = SIGBUS;
code = BUS_ADRERR;
} else if (fault & (VM_FAULT_HWPOISON | VM_FAULT_HWPOISON_LARGE)) {
sig = SIGBUS;
code = BUS_MCEERR_AR;
} else {
/*
* Something tried to access memory that isn't in our memory
* map.
*/
sig = SIGSEGV;
code = fault == VM_FAULT_BADACCESS ?
SEGV_ACCERR : SEGV_MAPERR;
}
__do_user_fault(tsk, addr, esr, sig, code, regs, fault);
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 (addr < TASK_SIZE)
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)
{
struct siginfo info;
const struct fault_info *inf;
inf = esr_to_fault_info(esr);
pr_err("Synchronous External Abort: %s (0x%08x) at 0x%016lx\n",
inf->name, esr, addr);
/*
* Synchronous aborts may interrupt code which had interrupts masked.
* Before calling out into the wider kernel tell the interested
* subsystems.
*/
if (IS_ENABLED(CONFIG_ACPI_APEI_SEA)) {
if (interrupts_enabled(regs))
nmi_enter();
ghes_notify_sea();
if (interrupts_enabled(regs))
nmi_exit();
}
info.si_signo = SIGBUS;
info.si_errno = 0;
info.si_code = BUS_FIXME;
if (esr & ESR_ELx_FnV)
info.si_addr = NULL;
else
info.si_addr = (void __user *)addr;
arm64_notify_die("", regs, &info, esr);
return 0;
}
static const struct fault_info fault_info[] = {
{ do_bad, SIGBUS, BUS_FIXME, "ttbr address size fault" },
{ do_bad, SIGBUS, BUS_FIXME, "level 1 address size fault" },
{ do_bad, SIGBUS, BUS_FIXME, "level 2 address size fault" },
{ do_bad, SIGBUS, BUS_FIXME, "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, SIGBUS, BUS_FIXME, "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, SIGBUS, BUS_FIXME, "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_FIXME, "synchronous external abort" },
{ do_bad, SIGBUS, BUS_FIXME, "unknown 17" },
{ do_bad, SIGBUS, BUS_FIXME, "unknown 18" },
{ do_bad, SIGBUS, BUS_FIXME, "unknown 19" },
{ do_sea, SIGBUS, BUS_FIXME, "level 0 (translation table walk)" },
{ do_sea, SIGBUS, BUS_FIXME, "level 1 (translation table walk)" },
{ do_sea, SIGBUS, BUS_FIXME, "level 2 (translation table walk)" },
{ do_sea, SIGBUS, BUS_FIXME, "level 3 (translation table walk)" },
{ do_sea, SIGBUS, BUS_FIXME, "synchronous parity or ECC error" }, // Reserved when RAS is implemented
{ do_bad, SIGBUS, BUS_FIXME, "unknown 25" },
{ do_bad, SIGBUS, BUS_FIXME, "unknown 26" },
{ do_bad, SIGBUS, BUS_FIXME, "unknown 27" },
{ do_sea, SIGBUS, BUS_FIXME, "level 0 synchronous parity error (translation table walk)" }, // Reserved when RAS is implemented
{ do_sea, SIGBUS, BUS_FIXME, "level 1 synchronous parity error (translation table walk)" }, // Reserved when RAS is implemented
{ do_sea, SIGBUS, BUS_FIXME, "level 2 synchronous parity error (translation table walk)" }, // Reserved when RAS is implemented
{ do_sea, SIGBUS, BUS_FIXME, "level 3 synchronous parity error (translation table walk)" }, // Reserved when RAS is implemented
{ do_bad, SIGBUS, BUS_FIXME, "unknown 32" },
{ do_alignment_fault, SIGBUS, BUS_ADRALN, "alignment fault" },
{ do_bad, SIGBUS, BUS_FIXME, "unknown 34" },
{ do_bad, SIGBUS, BUS_FIXME, "unknown 35" },
{ do_bad, SIGBUS, BUS_FIXME, "unknown 36" },
{ do_bad, SIGBUS, BUS_FIXME, "unknown 37" },
{ do_bad, SIGBUS, BUS_FIXME, "unknown 38" },
{ do_bad, SIGBUS, BUS_FIXME, "unknown 39" },
{ do_bad, SIGBUS, BUS_FIXME, "unknown 40" },
{ do_bad, SIGBUS, BUS_FIXME, "unknown 41" },
{ do_bad, SIGBUS, BUS_FIXME, "unknown 42" },
{ do_bad, SIGBUS, BUS_FIXME, "unknown 43" },
{ do_bad, SIGBUS, BUS_FIXME, "unknown 44" },
{ do_bad, SIGBUS, BUS_FIXME, "unknown 45" },
{ do_bad, SIGBUS, BUS_FIXME, "unknown 46" },
{ do_bad, SIGBUS, BUS_FIXME, "unknown 47" },
{ do_bad, SIGBUS, BUS_FIXME, "TLB conflict abort" },
{ do_bad, SIGBUS, BUS_FIXME, "Unsupported atomic hardware update fault" },
{ do_bad, SIGBUS, BUS_FIXME, "unknown 50" },
{ do_bad, SIGBUS, BUS_FIXME, "unknown 51" },
{ do_bad, SIGBUS, BUS_FIXME, "implementation fault (lockdown abort)" },
{ do_bad, SIGBUS, BUS_FIXME, "implementation fault (unsupported exclusive)" },
{ do_bad, SIGBUS, BUS_FIXME, "unknown 54" },
{ do_bad, SIGBUS, BUS_FIXME, "unknown 55" },
{ do_bad, SIGBUS, BUS_FIXME, "unknown 56" },
{ do_bad, SIGBUS, BUS_FIXME, "unknown 57" },
{ do_bad, SIGBUS, BUS_FIXME, "unknown 58" },
{ do_bad, SIGBUS, BUS_FIXME, "unknown 59" },
{ do_bad, SIGBUS, BUS_FIXME, "unknown 60" },
{ do_bad, SIGBUS, BUS_FIXME, "section domain fault" },
{ do_bad, SIGBUS, BUS_FIXME, "page domain fault" },
{ do_bad, SIGBUS, BUS_FIXME, "unknown 63" },
};
int handle_guest_sea(phys_addr_t addr, unsigned int esr)
{
int ret = -ENOENT;
if (IS_ENABLED(CONFIG_ACPI_APEI_SEA))
ret = ghes_notify_sea();
return ret;
}
asmlinkage void __exception do_mem_abort(unsigned long addr, unsigned int esr,
struct pt_regs *regs)
{
const struct fault_info *inf = esr_to_fault_info(esr);
struct siginfo info;
if (!inf->fn(addr, esr, regs))
return;
pr_alert("Unhandled fault: %s at 0x%016lx\n",
inf->name, addr);
mem_abort_decode(esr);
if (!user_mode(regs))
show_pte(addr);
info.si_signo = inf->sig;
info.si_errno = 0;
info.si_code = inf->code;
info.si_addr = (void __user *)addr;
arm64_notify_die("", regs, &info, esr);
}
asmlinkage void __exception do_el0_irq_bp_hardening(void)
{
/* PC has already been checked in entry.S */
arm64_apply_bp_hardening();
}
asmlinkage void __exception do_el0_ia_bp_hardening(unsigned long addr,
unsigned int esr,
struct pt_regs *regs)
{
/*
* We've taken an instruction abort from userspace and not yet
* re-enabled IRQs. If the address is a kernel address, apply
* BP hardening prior to enabling IRQs and pre-emption.
*/
if (addr > TASK_SIZE)
arm64_apply_bp_hardening();
local_irq_enable();
do_mem_abort(addr, esr, regs);
}
asmlinkage void __exception do_sp_pc_abort(unsigned long addr,
unsigned int esr,
struct pt_regs *regs)
{
struct siginfo info;
struct task_struct *tsk = current;
if (user_mode(regs)) {
if (instruction_pointer(regs) > TASK_SIZE)
arm64_apply_bp_hardening();
local_irq_enable();
}
if (show_unhandled_signals && unhandled_signal(tsk, SIGBUS))
pr_info_ratelimited("%s[%d]: %s exception: pc=%p sp=%p\n",
tsk->comm, task_pid_nr(tsk),
esr_get_class_string(esr), (void *)regs->pc,
(void *)regs->sp);
info.si_signo = SIGBUS;
info.si_errno = 0;
info.si_code = BUS_ADRALN;
info.si_addr = (void __user *)addr;
arm64_notify_die("Oops - SP/PC alignment exception", regs, &info, esr);
}
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, SIGBUS, BUS_FIXME, "unknown 3" },
{ do_bad, SIGTRAP, TRAP_BRKPT, "aarch32 BKPT" },
{ do_bad, SIGTRAP, TRAP_FIXME, "aarch32 vector catch" },
{ early_brk64, SIGTRAP, TRAP_BRKPT, "aarch64 BRK" },
{ do_bad, SIGBUS, BUS_FIXME, "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;
}
asmlinkage int __exception do_debug_exception(unsigned long addr,
unsigned int esr,
struct pt_regs *regs)
{
const struct fault_info *inf = debug_fault_info + DBG_ESR_EVT(esr);
struct siginfo info;
int rv;
/*
* Tell lockdep we disabled irqs in entry.S. Do nothing if they were
* already disabled to preserve the last enabled/disabled addresses.
*/
if (interrupts_enabled(regs))
trace_hardirqs_off();
if (user_mode(regs) && instruction_pointer(regs) > TASK_SIZE)
arm64_apply_bp_hardening();
if (!inf->fn(addr, esr, regs)) {
rv = 1;
} else {
pr_alert("Unhandled debug exception: %s (0x%08x) at 0x%016lx\n",
inf->name, esr, addr);
info.si_signo = inf->sig;
info.si_errno = 0;
info.si_code = inf->code;
info.si_addr = (void __user *)addr;
arm64_notify_die("", regs, &info, 0);
rv = 0;
}
if (interrupts_enabled(regs))
trace_hardirqs_on();
return rv;
}
NOKPROBE_SYMBOL(do_debug_exception);
#ifdef CONFIG_ARM64_PAN
int cpu_enable_pan(void *__unused)
{
/*
* We modify PSTATE. This won't work from irq context as the PSTATE
* is discarded once we return from the exception.
*/
WARN_ON_ONCE(in_interrupt());
config_sctlr_el1(SCTLR_EL1_SPAN, 0);
asm(SET_PSTATE_PAN(1));
return 0;
}
#endif /* CONFIG_ARM64_PAN */
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