Orange Pi5 kernel

 // SPDX-License-Identifier: GPL-2.0-or-later
/*
 * OpenRISC fault.c
 *
 * Linux architectural port borrowing liberally from similar works of
 * others.  All original copyrights apply as per the original source
 * declaration.
 *
 * Modifications for the OpenRISC architecture:
 * Copyright (C) 2003 Matjaz Breskvar <phoenix@bsemi.com>
 * Copyright (C) 2010-2011 Jonas Bonn <jonas@southpole.se>
 */
 
#include <linux/mm.h>
#include <linux/interrupt.h>
#include <linux/extable.h>
#include <linux/sched/signal.h>
#include <linux/perf_event.h>
 
#include <linux/uaccess.h>
#include <asm/siginfo.h>
#include <asm/signal.h>
 
#define NUM_TLB_ENTRIES 64
#define TLB_OFFSET(add) (((add) >> PAGE_SHIFT) & (NUM_TLB_ENTRIES-1))
 
unsigned long pte_misses;	/* updated by do_page_fault() */
unsigned long pte_errors;	/* updated by do_page_fault() */
 
/* __PHX__ :: - check the vmalloc_fault in do_page_fault()
 *            - also look into include/asm-or32/mmu_context.h
 */
volatile pgd_t *current_pgd[NR_CPUS];
 
extern void die(char *, struct pt_regs *, long);
 
/*
 * This routine handles page faults.  It determines the address,
 * and the problem, and then passes it off to one of the appropriate
 * routines.
 *
 * If this routine detects a bad access, it returns 1, otherwise it
 * returns 0.
 */
 
asmlinkage void do_page_fault(struct pt_regs *regs, unsigned long address,
<------><------><------>      unsigned long vector, int write_acc)
{
<------>struct task_struct *tsk;
<------>struct mm_struct *mm;
<------>struct vm_area_struct *vma;
<------>int si_code;
<------>vm_fault_t fault;
<------>unsigned int flags = FAULT_FLAG_DEFAULT;
 
<------>tsk = current;
 
<------>/*
<------> * We fault-in kernel-space virtual memory on-demand. The
<------> * 'reference' page table is init_mm.pgd.
<------> *
<------> * NOTE! We MUST NOT take any locks for this case. We may
<------> * be in an interrupt or a critical region, and should
<------> * only copy the information from the master page table,
<------> * nothing more.
<------> *
<------> * NOTE2: This is done so that, when updating the vmalloc
<------> * mappings we don't have to walk all processes pgdirs and
<------> * add the high mappings all at once. Instead we do it as they
<------> * are used. However vmalloc'ed page entries have the PAGE_GLOBAL
<------> * bit set so sometimes the TLB can use a lingering entry.
<------> *
<------> * This verifies that the fault happens in kernel space
<------> * and that the fault was not a protection error.
<------> */
 
<------>if (address >= VMALLOC_START &&
<------>    (vector != 0x300 && vector != 0x400) &&
<------>    !user_mode(regs))
<------><------>goto vmalloc_fault;
 
<------>/* If exceptions were enabled, we can reenable them here */
<------>if (user_mode(regs)) {
<------><------>/* Exception was in userspace: reenable interrupts */
<------><------>local_irq_enable();
<------><------>flags |= FAULT_FLAG_USER;
<------>} else {
<------><------>/* If exception was in a syscall, then IRQ's may have
<------><------> * been enabled or disabled.  If they were enabled,
<------><------> * reenable them.
<------><------> */
<------><------>if (regs->sr && (SPR_SR_IEE | SPR_SR_TEE))
<------><------><------>local_irq_enable();
<------>}
 
<------>mm = tsk->mm;
<------>si_code = SEGV_MAPERR;
 
<------>/*
<------> * If we're in an interrupt or have no user
<------> * context, we must not take the fault..
<------> */
 
<------>if (in_interrupt() || !mm)
<------><------>goto no_context;
 
<------>perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS, 1, regs, address);
 
retry:
<------>mmap_read_lock(mm);
<------>vma = find_vma(mm, address);
 
<------>if (!vma)
<------><------>goto bad_area;
 
<------>if (vma->vm_start <= address)
<------><------>goto good_area;
 
<------>if (!(vma->vm_flags & VM_GROWSDOWN))
<------><------>goto bad_area;
 
<------>if (user_mode(regs)) {
<------><------>/*
<------><------> * accessing the stack below usp is always a bug.
<------><------> * we get page-aligned addresses so we can only check
<------><------> * if we're within a page from usp, but that might be
<------><------> * enough to catch brutal errors at least.
<------><------> */
<------><------>if (address + PAGE_SIZE < regs->sp)
<------><------><------>goto bad_area;
<------>}
<------>if (expand_stack(vma, address))
<------><------>goto bad_area;
 
<------>/*
<------> * Ok, we have a good vm_area for this memory access, so
<------> * we can handle it..
<------> */
 
good_area:
<------>si_code = SEGV_ACCERR;
 
<------>/* first do some preliminary protection checks */
 
<------>if (write_acc) {
<------><------>if (!(vma->vm_flags & VM_WRITE))
<------><------><------>goto bad_area;
<------><------>flags |= FAULT_FLAG_WRITE;
<------>} else {
<------><------>/* not present */
<------><------>if (!(vma->vm_flags & (VM_READ | VM_EXEC)))
<------><------><------>goto bad_area;
<------>}
 
<------>/* are we trying to execute nonexecutable area */
<------>if ((vector == 0x400) && !(vma->vm_page_prot.pgprot & _PAGE_EXEC))
<------><------>goto bad_area;
 
<------>/*
<------> * If for any reason at all we couldn't handle the fault,
<------> * make sure we exit gracefully rather than endlessly redo
<------> * the fault.
<------> */
 
<------>fault = handle_mm_fault(vma, address, flags, regs);
 
<------>if (fault_signal_pending(fault, regs))
<------><------>return;
 
<------>if (unlikely(fault & VM_FAULT_ERROR)) {
<------><------>if (fault & VM_FAULT_OOM)
<------><------><------>goto out_of_memory;
<------><------>else if (fault & VM_FAULT_SIGSEGV)
<------><------><------>goto bad_area;
<------><------>else if (fault & VM_FAULT_SIGBUS)
<------><------><------>goto do_sigbus;
<------><------>BUG();
<------>}
 
<------>if (flags & FAULT_FLAG_ALLOW_RETRY) {
<------><------>/*RGD modeled on Cris */
<------><------>if (fault & VM_FAULT_RETRY) {
<------><------><------>flags |= FAULT_FLAG_TRIED;
 
<------><------><------> /* No need to mmap_read_unlock(mm) as we would
<------><------><------> * have already released it in __lock_page_or_retry
<------><------><------> * in mm/filemap.c.
<------><------><------> */
 
<------><------><------>goto retry;
<------><------>}
<------>}
 
<------>mmap_read_unlock(mm);
<------>return;
 
<------>/*
<------> * Something tried to access memory that isn't in our memory map..
<------> * Fix it, but check if it's kernel or user first..
<------> */
 
bad_area:
<------>mmap_read_unlock(mm);
 
bad_area_nosemaphore:
 
<------>/* User mode accesses just cause a SIGSEGV */
 
<------>if (user_mode(regs)) {
<------><------>force_sig_fault(SIGSEGV, si_code, (void __user *)address);
<------><------>return;
<------>}
 
no_context:
 
<------>/* Are we prepared to handle this kernel fault?
<------> *
<------> * (The kernel has valid exception-points in the source
<------> *  when it acesses user-memory. When it fails in one
<------> *  of those points, we find it in a table and do a jump
<------> *  to some fixup code that loads an appropriate error
<------> *  code)
<------> */
 
<------>{
<------><------>const struct exception_table_entry *entry;
 
<------><------>__asm__ __volatile__("l.nop 42");
 
<------><------>if ((entry = search_exception_tables(regs->pc)) != NULL) {
<------><------><------>/* Adjust the instruction pointer in the stackframe */
<------><------><------>regs->pc = entry->fixup;
<------><------><------>return;
<------><------>}
<------>}
 
<------>/*
<------> * Oops. The kernel tried to access some bad page. We'll have to
<------> * terminate things with extreme prejudice.
<------> */
 
<------>if ((unsigned long)(address) < PAGE_SIZE)
<------><------>printk(KERN_ALERT
<------><------>       "Unable to handle kernel NULL pointer dereference");
<------>else
<------><------>printk(KERN_ALERT "Unable to handle kernel access");
<------>printk(" at virtual address 0x%08lx\n", address);
 
<------>die("Oops", regs, write_acc);
 
<------>do_exit(SIGKILL);
 
<------>/*
<------> * We ran out of memory, or some other thing happened to us that made
<------> * us unable to handle the page fault gracefully.
<------> */
 
out_of_memory:
<------>__asm__ __volatile__("l.nop 42");
<------>__asm__ __volatile__("l.nop 1");
 
<------>mmap_read_unlock(mm);
<------>if (!user_mode(regs))
<------><------>goto no_context;
<------>pagefault_out_of_memory();
<------>return;
 
do_sigbus:
<------>mmap_read_unlock(mm);
 
<------>/*
<------> * Send a sigbus, regardless of whether we were in kernel
<------> * or user mode.
<------> */
<------>force_sig_fault(SIGBUS, BUS_ADRERR, (void __user *)address);
 
<------>/* Kernel mode? Handle exceptions or die */
<------>if (!user_mode(regs))
<------><------>goto no_context;
<------>return;
 
vmalloc_fault:
<------>{
<------><------>/*
<------><------> * Synchronize this task's top level page-table
<------><------> * with the 'reference' page table.
<------><------> *
<------><------> * Use current_pgd instead of tsk->active_mm->pgd
<------><------> * since the latter might be unavailable if this
<------><------> * code is executed in a misfortunately run irq
<------><------> * (like inside schedule() between switch_mm and
<------><------> *  switch_to...).
<------><------> */
 
<------><------>int offset = pgd_index(address);
<------><------>pgd_t *pgd, *pgd_k;
<------><------>p4d_t *p4d, *p4d_k;
<------><------>pud_t *pud, *pud_k;
<------><------>pmd_t *pmd, *pmd_k;
<------><------>pte_t *pte_k;
 
/*
<------><------>phx_warn("do_page_fault(): vmalloc_fault will not work, "
<------><------><------> "since current_pgd assign a proper value somewhere\n"
<------><------><------> "anyhow we don't need this at the moment\n");
 
<------><------>phx_mmu("vmalloc_fault");
*/
<------><------>pgd = (pgd_t *)current_pgd[smp_processor_id()] + offset;
<------><------>pgd_k = init_mm.pgd + offset;
 
<------><------>/* Since we're two-level, we don't need to do both
<------><------> * set_pgd and set_pmd (they do the same thing). If
<------><------> * we go three-level at some point, do the right thing
<------><------> * with pgd_present and set_pgd here.
<------><------> *
<------><------> * Also, since the vmalloc area is global, we don't
<------><------> * need to copy individual PTE's, it is enough to
<------><------> * copy the pgd pointer into the pte page of the
<------><------> * root task. If that is there, we'll find our pte if
<------><------> * it exists.
<------><------> */
 
<------><------>p4d = p4d_offset(pgd, address);
<------><------>p4d_k = p4d_offset(pgd_k, address);
<------><------>if (!p4d_present(*p4d_k))
<------><------><------>goto no_context;
 
<------><------>pud = pud_offset(p4d, address);
<------><------>pud_k = pud_offset(p4d_k, address);
<------><------>if (!pud_present(*pud_k))
<------><------><------>goto no_context;
 
<------><------>pmd = pmd_offset(pud, address);
<------><------>pmd_k = pmd_offset(pud_k, address);
 
<------><------>if (!pmd_present(*pmd_k))
<------><------><------>goto bad_area_nosemaphore;
 
<------><------>set_pmd(pmd, *pmd_k);
 
<------><------>/* Make sure the actual PTE exists as well to
<------><------> * catch kernel vmalloc-area accesses to non-mapped
<------><------> * addresses. If we don't do this, this will just
<------><------> * silently loop forever.
<------><------> */
 
<------><------>pte_k = pte_offset_kernel(pmd_k, address);
<------><------>if (!pte_present(*pte_k))
<------><------><------>goto no_context;
 
<------><------>return;
<------>}
}

	// SPDX-License-Identifier: GPL-2.0-or-later
	/*
	* OpenRISC fault.c
	*
	* Linux architectural port borrowing liberally from similar works of
	* others. All original copyrights apply as per the original source
	* declaration.
	*
	* Modifications for the OpenRISC architecture:
	* Copyright (C) 2003 Matjaz Breskvar <phoenix@bsemi.com>
	* Copyright (C) 2010-2011 Jonas Bonn <jonas@southpole.se>
	*/

	#include <linux/mm.h>
	#include <linux/interrupt.h>
	#include <linux/extable.h>
	#include <linux/sched/signal.h>
	#include <linux/perf_event.h>

	#include <linux/uaccess.h>
	#include <asm/siginfo.h>
	#include <asm/signal.h>

	#define NUM_TLB_ENTRIES 64
	#define TLB_OFFSET(add) (((add) >> PAGE_SHIFT) & (NUM_TLB_ENTRIES-1))

	unsigned long pte_misses; /* updated by do_page_fault() */
	unsigned long pte_errors; /* updated by do_page_fault() */

	/* __PHX__ :: - check the vmalloc_fault in do_page_fault()
	* - also look into include/asm-or32/mmu_context.h
	*/
	volatile pgd_t *current_pgd[NR_CPUS];

	extern void die(char , struct pt_regs , long);

	/*
	* This routine handles page faults. It determines the address,
	* and the problem, and then passes it off to one of the appropriate
	* routines.
	*
	* If this routine detects a bad access, it returns 1, otherwise it
	* returns 0.
	*/

	asmlinkage void do_page_fault(struct pt_regs *regs, unsigned long address,
	<------><------><------> unsigned long vector, int write_acc)
	{
	<------>struct task_struct *tsk;
	<------>struct mm_struct *mm;
	<------>struct vm_area_struct *vma;
	<------>int si_code;
	<------>vm_fault_t fault;
	<------>unsigned int flags = FAULT_FLAG_DEFAULT;

	<------>tsk = current;

	<------>/*
	<------> * We fault-in kernel-space virtual memory on-demand. The
	<------> * 'reference' page table is init_mm.pgd.
	<------> *
	<------> * NOTE! We MUST NOT take any locks for this case. We may
	<------> * be in an interrupt or a critical region, and should
	<------> * only copy the information from the master page table,
	<------> * nothing more.
	<------> *
	<------> * NOTE2: This is done so that, when updating the vmalloc
	<------> * mappings we don't have to walk all processes pgdirs and
	<------> * add the high mappings all at once. Instead we do it as they
	<------> * are used. However vmalloc'ed page entries have the PAGE_GLOBAL
	<------> * bit set so sometimes the TLB can use a lingering entry.
	<------> *
	<------> * This verifies that the fault happens in kernel space
	<------> * and that the fault was not a protection error.
	<------> */

	<------>if (address >= VMALLOC_START &&
	<------> (vector != 0x300 && vector != 0x400) &&
	<------> !user_mode(regs))
	<------><------>goto vmalloc_fault;

	<------>/* If exceptions were enabled, we can reenable them here */
	<------>if (user_mode(regs)) {
	<------><------>/* Exception was in userspace: reenable interrupts */
	<------><------>local_irq_enable();
	<------><------>flags \|= FAULT_FLAG_USER;
	<------>} else {
	<------><------>/* If exception was in a syscall, then IRQ's may have
	<------><------> * been enabled or disabled. If they were enabled,
	<------><------> * reenable them.
	<------><------> */
	<------><------>if (regs->sr && (SPR_SR_IEE \| SPR_SR_TEE))
	<------><------><------>local_irq_enable();
	<------>}

	<------>mm = tsk->mm;
	<------>si_code = SEGV_MAPERR;

	<------>/*
	<------> * If we're in an interrupt or have no user
	<------> * context, we must not take the fault..
	<------> */

	<------>if (in_interrupt() \|\| !mm)
	<------><------>goto no_context;

	<------>perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS, 1, regs, address);

	retry:
	<------>mmap_read_lock(mm);
	<------>vma = find_vma(mm, address);

	<------>if (!vma)
	<------><------>goto bad_area;

	<------>if (vma->vm_start <= address)
	<------><------>goto good_area;

	<------>if (!(vma->vm_flags & VM_GROWSDOWN))
	<------><------>goto bad_area;

	<------>if (user_mode(regs)) {
	<------><------>/*
	<------><------> * accessing the stack below usp is always a bug.
	<------><------> * we get page-aligned addresses so we can only check
	<------><------> * if we're within a page from usp, but that might be
	<------><------> * enough to catch brutal errors at least.
	<------><------> */
	<------><------>if (address + PAGE_SIZE < regs->sp)
	<------><------><------>goto bad_area;
	<------>}
	<------>if (expand_stack(vma, address))
	<------><------>goto bad_area;

	<------>/*
	<------> * Ok, we have a good vm_area for this memory access, so
	<------> * we can handle it..
	<------> */

	good_area:
	<------>si_code = SEGV_ACCERR;

	<------>/* first do some preliminary protection checks */

	<------>if (write_acc) {
	<------><------>if (!(vma->vm_flags & VM_WRITE))
	<------><------><------>goto bad_area;
	<------><------>flags \|= FAULT_FLAG_WRITE;
	<------>} else {
	<------><------>/* not present */
	<------><------>if (!(vma->vm_flags & (VM_READ \| VM_EXEC)))
	<------><------><------>goto bad_area;
	<------>}

	<------>/* are we trying to execute nonexecutable area */
	<------>if ((vector == 0x400) && !(vma->vm_page_prot.pgprot & _PAGE_EXEC))
	<------><------>goto bad_area;

	<------>/*
	<------> * If for any reason at all we couldn't handle the fault,
	<------> * make sure we exit gracefully rather than endlessly redo
	<------> * the fault.
	<------> */

	<------>fault = handle_mm_fault(vma, address, flags, regs);

	<------>if (fault_signal_pending(fault, regs))
	<------><------>return;

	<------>if (unlikely(fault & VM_FAULT_ERROR)) {
	<------><------>if (fault & VM_FAULT_OOM)
	<------><------><------>goto out_of_memory;
	<------><------>else if (fault & VM_FAULT_SIGSEGV)
	<------><------><------>goto bad_area;
	<------><------>else if (fault & VM_FAULT_SIGBUS)
	<------><------><------>goto do_sigbus;
	<------><------>BUG();
	<------>}

	<------>if (flags & FAULT_FLAG_ALLOW_RETRY) {
	<------><------>/RGD modeled on Cris /
	<------><------>if (fault & VM_FAULT_RETRY) {
	<------><------><------>flags \|= FAULT_FLAG_TRIED;

	<------><------><------> /* No need to mmap_read_unlock(mm) as we would
	<------><------><------> * have already released it in __lock_page_or_retry
	<------><------><------> * in mm/filemap.c.
	<------><------><------> */

	<------><------><------>goto retry;
	<------><------>}
	<------>}

	<------>mmap_read_unlock(mm);
	<------>return;

	<------>/*
	<------> * Something tried to access memory that isn't in our memory map..
	<------> * Fix it, but check if it's kernel or user first..
	<------> */

	bad_area:
	<------>mmap_read_unlock(mm);

	bad_area_nosemaphore:

	<------>/* User mode accesses just cause a SIGSEGV */

	<------>if (user_mode(regs)) {
	<------><------>force_sig_fault(SIGSEGV, si_code, (void __user *)address);
	<------><------>return;
	<------>}

	no_context:

	<------>/* Are we prepared to handle this kernel fault?
	<------> *
	<------> * (The kernel has valid exception-points in the source
	<------> * when it acesses user-memory. When it fails in one
	<------> * of those points, we find it in a table and do a jump
	<------> * to some fixup code that loads an appropriate error
	<------> * code)
	<------> */

	<------>{
	<------><------>const struct exception_table_entry *entry;

	<------><------>__asm__ __volatile__("l.nop 42");

	<------><------>if ((entry = search_exception_tables(regs->pc)) != NULL) {
	<------><------><------>/* Adjust the instruction pointer in the stackframe */
	<------><------><------>regs->pc = entry->fixup;
	<------><------><------>return;
	<------><------>}
	<------>}

	<------>/*
	<------> * Oops. The kernel tried to access some bad page. We'll have to
	<------> * terminate things with extreme prejudice.
	<------> */

	<------>if ((unsigned long)(address) < PAGE_SIZE)
	<------><------>printk(KERN_ALERT
	<------><------> "Unable to handle kernel NULL pointer dereference");
	<------>else
	<------><------>printk(KERN_ALERT "Unable to handle kernel access");
	<------>printk(" at virtual address 0x%08lx\n", address);

	<------>die("Oops", regs, write_acc);

	<------>do_exit(SIGKILL);

	<------>/*
	<------> * We ran out of memory, or some other thing happened to us that made
	<------> * us unable to handle the page fault gracefully.
	<------> */

	out_of_memory:
	<------>__asm__ __volatile__("l.nop 42");
	<------>__asm__ __volatile__("l.nop 1");

	<------>mmap_read_unlock(mm);
	<------>if (!user_mode(regs))
	<------><------>goto no_context;
	<------>pagefault_out_of_memory();
	<------>return;

	do_sigbus:
	<------>mmap_read_unlock(mm);

	<------>/*
	<------> * Send a sigbus, regardless of whether we were in kernel
	<------> * or user mode.
	<------> */
	<------>force_sig_fault(SIGBUS, BUS_ADRERR, (void __user *)address);

	<------>/* Kernel mode? Handle exceptions or die */
	<------>if (!user_mode(regs))
	<------><------>goto no_context;
	<------>return;

	vmalloc_fault:
	<------>{
	<------><------>/*
	<------><------> * Synchronize this task's top level page-table
	<------><------> * with the 'reference' page table.
	<------><------> *
	<------><------> * Use current_pgd instead of tsk->active_mm->pgd
	<------><------> * since the latter might be unavailable if this
	<------><------> * code is executed in a misfortunately run irq
	<------><------> * (like inside schedule() between switch_mm and
	<------><------> * switch_to...).
	<------><------> */

	<------><------>int offset = pgd_index(address);
	<------><------>pgd_t pgd, pgd_k;
	<------><------>p4d_t p4d, p4d_k;
	<------><------>pud_t pud, pud_k;
	<------><------>pmd_t pmd, pmd_k;
	<------><------>pte_t *pte_k;

	/*
	<------><------>phx_warn("do_page_fault(): vmalloc_fault will not work, "
	<------><------><------> "since current_pgd assign a proper value somewhere\n"
	<------><------><------> "anyhow we don't need this at the moment\n");

	<------><------>phx_mmu("vmalloc_fault");
	*/
	<------><------>pgd = (pgd_t *)current_pgd[smp_processor_id()] + offset;
	<------><------>pgd_k = init_mm.pgd + offset;

	<------><------>/* Since we're two-level, we don't need to do both
	<------><------> * set_pgd and set_pmd (they do the same thing). If
	<------><------> * we go three-level at some point, do the right thing
	<------><------> * with pgd_present and set_pgd here.
	<------><------> *
	<------><------> * Also, since the vmalloc area is global, we don't
	<------><------> * need to copy individual PTE's, it is enough to
	<------><------> * copy the pgd pointer into the pte page of the
	<------><------> * root task. If that is there, we'll find our pte if
	<------><------> * it exists.
	<------><------> */

	<------><------>p4d = p4d_offset(pgd, address);
	<------><------>p4d_k = p4d_offset(pgd_k, address);
	<------><------>if (!p4d_present(*p4d_k))
	<------><------><------>goto no_context;

	<------><------>pud = pud_offset(p4d, address);
	<------><------>pud_k = pud_offset(p4d_k, address);
	<------><------>if (!pud_present(*pud_k))
	<------><------><------>goto no_context;

	<------><------>pmd = pmd_offset(pud, address);
	<------><------>pmd_k = pmd_offset(pud_k, address);

	<------><------>if (!pmd_present(*pmd_k))
	<------><------><------>goto bad_area_nosemaphore;

	<------><------>set_pmd(pmd, *pmd_k);

	<------><------>/* Make sure the actual PTE exists as well to
	<------><------> * catch kernel vmalloc-area accesses to non-mapped
	<------><------> * addresses. If we don't do this, this will just
	<------><------> * silently loop forever.
	<------><------> */

	<------><------>pte_k = pte_offset_kernel(pmd_k, address);
	<------><------>if (!pte_present(*pte_k))
	<------><------><------>goto no_context;

	<------><------>return;
	<------>}
	}