189 lines
4.2 KiB
C
189 lines
4.2 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
|
|
/* Page Fault Handling for ARC (TLB Miss / ProtV)
|
|
*
|
|
* Copyright (C) 2004, 2007-2010, 2011-2012 Synopsys, Inc. (www.synopsys.com)
|
|
*/
|
|
|
|
#include <linux/signal.h>
|
|
#include <linux/interrupt.h>
|
|
#include <linux/sched/signal.h>
|
|
#include <linux/errno.h>
|
|
#include <linux/ptrace.h>
|
|
#include <linux/uaccess.h>
|
|
#include <linux/kdebug.h>
|
|
#include <linux/perf_event.h>
|
|
#include <linux/mm_types.h>
|
|
#include <asm/mmu.h>
|
|
|
|
/*
|
|
* kernel virtual address is required to implement vmalloc/pkmap/fixmap
|
|
* Refer to asm/processor.h for System Memory Map
|
|
*
|
|
* It simply copies the PMD entry (pointer to 2nd level page table or hugepage)
|
|
* from swapper pgdir to task pgdir. The 2nd level table/page is thus shared
|
|
*/
|
|
noinline static int handle_kernel_vaddr_fault(unsigned long address)
|
|
{
|
|
/*
|
|
* Synchronize this task's top level page-table
|
|
* with the 'reference' page table.
|
|
*/
|
|
pgd_t *pgd, *pgd_k;
|
|
p4d_t *p4d, *p4d_k;
|
|
pud_t *pud, *pud_k;
|
|
pmd_t *pmd, *pmd_k;
|
|
|
|
pgd = pgd_offset_fast(current->active_mm, address);
|
|
pgd_k = pgd_offset_k(address);
|
|
|
|
if (!pgd_present(*pgd_k))
|
|
goto bad_area;
|
|
|
|
p4d = p4d_offset(pgd, address);
|
|
p4d_k = p4d_offset(pgd_k, address);
|
|
if (!p4d_present(*p4d_k))
|
|
goto bad_area;
|
|
|
|
pud = pud_offset(p4d, address);
|
|
pud_k = pud_offset(p4d_k, address);
|
|
if (!pud_present(*pud_k))
|
|
goto bad_area;
|
|
|
|
pmd = pmd_offset(pud, address);
|
|
pmd_k = pmd_offset(pud_k, address);
|
|
if (!pmd_present(*pmd_k))
|
|
goto bad_area;
|
|
|
|
set_pmd(pmd, *pmd_k);
|
|
|
|
/* XXX: create the TLB entry here */
|
|
return 0;
|
|
|
|
bad_area:
|
|
return 1;
|
|
}
|
|
|
|
void do_page_fault(unsigned long address, struct pt_regs *regs)
|
|
{
|
|
struct vm_area_struct *vma = NULL;
|
|
struct task_struct *tsk = current;
|
|
struct mm_struct *mm = tsk->mm;
|
|
int sig, si_code = SEGV_MAPERR;
|
|
unsigned int write = 0, exec = 0, mask;
|
|
vm_fault_t fault = VM_FAULT_SIGSEGV; /* handle_mm_fault() output */
|
|
unsigned int flags; /* handle_mm_fault() input */
|
|
|
|
/*
|
|
* 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.
|
|
*/
|
|
if (address >= VMALLOC_START && !user_mode(regs)) {
|
|
if (unlikely(handle_kernel_vaddr_fault(address)))
|
|
goto no_context;
|
|
else
|
|
return;
|
|
}
|
|
|
|
/*
|
|
* 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 (regs->ecr_cause & ECR_C_PROTV_STORE) /* ST/EX */
|
|
write = 1;
|
|
else if ((regs->ecr_vec == ECR_V_PROTV) &&
|
|
(regs->ecr_cause == ECR_C_PROTV_INST_FETCH))
|
|
exec = 1;
|
|
|
|
flags = FAULT_FLAG_DEFAULT;
|
|
if (user_mode(regs))
|
|
flags |= FAULT_FLAG_USER;
|
|
if (write)
|
|
flags |= FAULT_FLAG_WRITE;
|
|
|
|
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 (unlikely(address < vma->vm_start)) {
|
|
if (!(vma->vm_flags & VM_GROWSDOWN) || expand_stack(vma, address))
|
|
goto bad_area;
|
|
}
|
|
|
|
/*
|
|
* vm_area is good, now check permissions for this memory access
|
|
*/
|
|
mask = VM_READ;
|
|
if (write)
|
|
mask = VM_WRITE;
|
|
if (exec)
|
|
mask = VM_EXEC;
|
|
|
|
if (!(vma->vm_flags & mask)) {
|
|
si_code = SEGV_ACCERR;
|
|
goto bad_area;
|
|
}
|
|
|
|
fault = handle_mm_fault(vma, address, flags, regs);
|
|
|
|
/* Quick path to respond to signals */
|
|
if (fault_signal_pending(fault, regs)) {
|
|
if (!user_mode(regs))
|
|
goto no_context;
|
|
return;
|
|
}
|
|
|
|
/*
|
|
* Fault retry nuances, mmap_lock already relinquished by core mm
|
|
*/
|
|
if (unlikely((fault & VM_FAULT_RETRY) &&
|
|
(flags & FAULT_FLAG_ALLOW_RETRY))) {
|
|
flags |= FAULT_FLAG_TRIED;
|
|
goto retry;
|
|
}
|
|
|
|
bad_area:
|
|
mmap_read_unlock(mm);
|
|
|
|
/*
|
|
* Major/minor page fault accounting
|
|
* (in case of retry we only land here once)
|
|
*/
|
|
if (likely(!(fault & VM_FAULT_ERROR)))
|
|
/* Normal return path: fault Handled Gracefully */
|
|
return;
|
|
|
|
if (!user_mode(regs))
|
|
goto no_context;
|
|
|
|
if (fault & VM_FAULT_OOM) {
|
|
pagefault_out_of_memory();
|
|
return;
|
|
}
|
|
|
|
if (fault & VM_FAULT_SIGBUS) {
|
|
sig = SIGBUS;
|
|
si_code = BUS_ADRERR;
|
|
}
|
|
else {
|
|
sig = SIGSEGV;
|
|
}
|
|
|
|
tsk->thread.fault_address = address;
|
|
force_sig_fault(sig, si_code, (void __user *)address);
|
|
return;
|
|
|
|
no_context:
|
|
if (fixup_exception(regs))
|
|
return;
|
|
|
|
die("Oops", regs, address);
|
|
}
|