Release 4.14 arch/ia64/mm/fault.c
// SPDX-License-Identifier: GPL-2.0
/*
* MMU fault handling support.
*
* Copyright (C) 1998-2002 Hewlett-Packard Co
* David Mosberger-Tang <davidm@hpl.hp.com>
*/
#include <linux/sched/signal.h>
#include <linux/kernel.h>
#include <linux/mm.h>
#include <linux/extable.h>
#include <linux/interrupt.h>
#include <linux/kprobes.h>
#include <linux/kdebug.h>
#include <linux/prefetch.h>
#include <linux/uaccess.h>
#include <asm/pgtable.h>
#include <asm/processor.h>
#include <asm/exception.h>
extern int die(char *, struct pt_regs *, long);
#ifdef CONFIG_KPROBES
static inline int notify_page_fault(struct pt_regs *regs, int trap)
{
int ret = 0;
if (!user_mode(regs)) {
/* kprobe_running() needs smp_processor_id() */
preempt_disable();
if (kprobe_running() && kprobe_fault_handler(regs, trap))
ret = 1;
preempt_enable();
}
return ret;
}
Contributors
| Person | Tokens | Prop | Commits | CommitProp |
| Christoph Hellwig | 32 | 57.14% | 1 | 33.33% |
| Anil S Keshavamurthy | 23 | 41.07% | 1 | 33.33% |
| Harvey Harrison | 1 | 1.79% | 1 | 33.33% |
| Total | 56 | 100.00% | 3 | 100.00% |
#else
static inline int notify_page_fault(struct pt_regs *regs, int trap)
{
return 0;
}
Contributors
| Person | Tokens | Prop | Commits | CommitProp |
| Anil S Keshavamurthy | 17 | 94.44% | 1 | 50.00% |
| Christoph Hellwig | 1 | 5.56% | 1 | 50.00% |
| Total | 18 | 100.00% | 2 | 100.00% |
#endif
/*
* Return TRUE if ADDRESS points at a page in the kernel's mapped segment
* (inside region 5, on ia64) and that page is present.
*/
static int
mapped_kernel_page_is_present (unsigned long address)
{
pgd_t *pgd;
pud_t *pud;
pmd_t *pmd;
pte_t *ptep, pte;
pgd = pgd_offset_k(address);
if (pgd_none(*pgd) || pgd_bad(*pgd))
return 0;
pud = pud_offset(pgd, address);
if (pud_none(*pud) || pud_bad(*pud))
return 0;
pmd = pmd_offset(pud, address);
if (pmd_none(*pmd) || pmd_bad(*pmd))
return 0;
ptep = pte_offset_kernel(pmd, address);
if (!ptep)
return 0;
pte = *ptep;
return pte_present(pte);
}
Contributors
| Person | Tokens | Prop | Commits | CommitProp |
| David Mosberger-Tang | 101 | 76.52% | 1 | 50.00% |
| Nicholas Piggin | 31 | 23.48% | 1 | 50.00% |
| Total | 132 | 100.00% | 2 | 100.00% |
# define VM_READ_BIT 0
# define VM_WRITE_BIT 1
# define VM_EXEC_BIT 2
void __kprobes
ia64_do_page_fault (unsigned long address, unsigned long isr, struct pt_regs *regs)
{
int signal = SIGSEGV, code = SEGV_MAPERR;
struct vm_area_struct *vma, *prev_vma;
struct mm_struct *mm = current->mm;
struct siginfo si;
unsigned long mask;
int fault;
unsigned int flags = FAULT_FLAG_ALLOW_RETRY | FAULT_FLAG_KILLABLE;
mask = ((((isr >> IA64_ISR_X_BIT) & 1UL) << VM_EXEC_BIT)
| (((isr >> IA64_ISR_W_BIT) & 1UL) << VM_WRITE_BIT));
/* mmap_sem is performance critical.... */
prefetchw(&mm->mmap_sem);
/*
* If we're in an interrupt or have no user context, we must not take the fault..
*/
if (faulthandler_disabled() || !mm)
goto no_context;
#ifdef CONFIG_VIRTUAL_MEM_MAP
/*
* If fault is in region 5 and we are in the kernel, we may already
* have the mmap_sem (pfn_valid macro is called during mmap). There
* is no vma for region 5 addr's anyway, so skip getting the semaphore
* and go directly to the exception handling code.
*/
if ((REGION_NUMBER(address) == 5) && !user_mode(regs))
goto bad_area_no_up;
#endif
/*
* This is to handle the kprobes on user space access instructions
*/
if (notify_page_fault(regs, TRAP_BRKPT))
return;
if (user_mode(regs))
flags |= FAULT_FLAG_USER;
if (mask & VM_WRITE)
flags |= FAULT_FLAG_WRITE;
retry:
down_read(&mm->mmap_sem);
vma = find_vma_prev(mm, address, &prev_vma);
if (!vma && !prev_vma )
goto bad_area;
/*
* find_vma_prev() returns vma such that address < vma->vm_end or NULL
*
* May find no vma, but could be that the last vm area is the
* register backing store that needs to expand upwards, in
* this case vma will be null, but prev_vma will ne non-null
*/
if (( !vma && prev_vma ) || (address < vma->vm_start) )
goto check_expansion;
good_area:
code = SEGV_ACCERR;
/* OK, we've got a good vm_area for this memory area. Check the access permissions: */
# if (((1 << VM_READ_BIT) != VM_READ || (1 << VM_WRITE_BIT) != VM_WRITE) \
|| (1 << VM_EXEC_BIT) != VM_EXEC)
# error File is out of sync with <linux/mm.h>. Please update.
# endif
if (((isr >> IA64_ISR_R_BIT) & 1UL) && (!(vma->vm_flags & (VM_READ | VM_WRITE))))
goto bad_area;
if ((vma->vm_flags & mask) != mask)
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);
if ((fault & VM_FAULT_RETRY) && fatal_signal_pending(current))
return;
if (unlikely(fault & VM_FAULT_ERROR)) {
/*
* We ran out of memory, or some other thing happened
* to us that made us unable to handle the page fault
* gracefully.
*/
if (fault & VM_FAULT_OOM) {
goto out_of_memory;
} else if (fault & VM_FAULT_SIGSEGV) {
goto bad_area;
} else if (fault & VM_FAULT_SIGBUS) {
signal = SIGBUS;
goto bad_area;
}
BUG();
}
if (flags & FAULT_FLAG_ALLOW_RETRY) {
if (fault & VM_FAULT_MAJOR)
current->maj_flt++;
else
current->min_flt++;
if (fault & VM_FAULT_RETRY) {
flags &= ~FAULT_FLAG_ALLOW_RETRY;
flags |= FAULT_FLAG_TRIED;
/* No need to up_read(&mm->mmap_sem) as we would
* have already released it in __lock_page_or_retry
* in mm/filemap.c.
*/
goto retry;
}
}
up_read(&mm->mmap_sem);
return;
check_expansion:
if (!(prev_vma && (prev_vma->vm_flags & VM_GROWSUP) && (address == prev_vma->vm_end))) {
if (!vma)
goto bad_area;
if (!(vma->vm_flags & VM_GROWSDOWN))
goto bad_area;
if (REGION_NUMBER(address) != REGION_NUMBER(vma->vm_start)
|| REGION_OFFSET(address) >= RGN_MAP_LIMIT)
goto bad_area;
if (expand_stack(vma, address))
goto bad_area;
} else {
vma = prev_vma;
if (REGION_NUMBER(address) != REGION_NUMBER(vma->vm_start)
|| REGION_OFFSET(address) >= RGN_MAP_LIMIT)
goto bad_area;
/*
* Since the register backing store is accessed sequentially,
* we disallow growing it by more than a page at a time.
*/
if (address > vma->vm_end + PAGE_SIZE - sizeof(long))
goto bad_area;
if (expand_upwards(vma, address))
goto bad_area;
}
goto good_area;
bad_area:
up_read(&mm->mmap_sem);
#ifdef CONFIG_VIRTUAL_MEM_MAP
bad_area_no_up:
#endif
if ((isr & IA64_ISR_SP)
|| ((isr & IA64_ISR_NA) && (isr & IA64_ISR_CODE_MASK) == IA64_ISR_CODE_LFETCH))
{
/*
* This fault was due to a speculative load or lfetch.fault, set the "ed"
* bit in the psr to ensure forward progress. (Target register will get a
* NaT for ld.s, lfetch will be canceled.)
*/
ia64_psr(regs)->ed = 1;
return;
}
if (user_mode(regs)) {
si.si_signo = signal;
si.si_errno = 0;
si.si_code = code;
si.si_addr = (void __user *) address;
si.si_isr = isr;
si.si_flags = __ISR_VALID;
force_sig_info(signal, &si, current);
return;
}
no_context:
if ((isr & IA64_ISR_SP)
|| ((isr & IA64_ISR_NA) && (isr & IA64_ISR_CODE_MASK) == IA64_ISR_CODE_LFETCH))
{
/*
* This fault was due to a speculative load or lfetch.fault, set the "ed"
* bit in the psr to ensure forward progress. (Target register will get a
* NaT for ld.s, lfetch will be canceled.)
*/
ia64_psr(regs)->ed = 1;
return;
}
/*
* Since we have no vma's for region 5, we might get here even if the address is
* valid, due to the VHPT walker inserting a non present translation that becomes
* stale. If that happens, the non present fault handler already purged the stale
* translation, which fixed the problem. So, we check to see if the translation is
* valid, and return if it is.
*/
if (REGION_NUMBER(address) == 5 && mapped_kernel_page_is_present(address))
return;
if (ia64_done_with_exception(regs))
return;
/*
* Oops. The kernel tried to access some bad page. We'll have to terminate things
* with extreme prejudice.
*/
bust_spinlocks(1);
if (address < PAGE_SIZE)
printk(KERN_ALERT "Unable to handle kernel NULL pointer dereference (address %016lx)\n", address);
else
printk(KERN_ALERT "Unable to handle kernel paging request at "
"virtual address %016lx\n", address);
if (die("Oops", regs, isr))
regs = NULL;
bust_spinlocks(0);
if (regs)
do_exit(SIGKILL);
return;
out_of_memory:
up_read(&mm->mmap_sem);
if (!user_mode(regs))
goto no_context;
pagefault_out_of_memory();
}
Contributors
| Person | Tokens | Prop | Commits | CommitProp |
| Linus Torvalds (pre-git) | 421 | 48.78% | 3 | 9.68% |
| David Mosberger-Tang | 94 | 10.89% | 8 | 25.81% |
| Kautuk Consul | 80 | 9.27% | 1 | 3.23% |
| Linus Torvalds | 65 | 7.53% | 3 | 9.68% |
| Nicholas Piggin | 54 | 6.26% | 2 | 6.45% |
| Andrew Burgess | 21 | 2.43% | 1 | 3.23% |
| Jason Baron | 21 | 2.43% | 1 | 3.23% |
| Johannes Weiner | 21 | 2.43% | 1 | 3.23% |
| Hugh Dickins | 20 | 2.32% | 1 | 3.23% |
| Tony Luck | 19 | 2.20% | 1 | 3.23% |
| Anil S Keshavamurthy | 11 | 1.27% | 2 | 6.45% |
| Jan Beulich | 10 | 1.16% | 1 | 3.23% |
| Christoph Lameter | 9 | 1.04% | 1 | 3.23% |
| Kiyoshi Ueda | 8 | 0.93% | 1 | 3.23% |
| Shaohua Li | 4 | 0.46% | 1 | 3.23% |
| Björn Helgaas | 3 | 0.35% | 1 | 3.23% |
| Prasanna S. Panchamukhi | 1 | 0.12% | 1 | 3.23% |
| David Hildenbrand | 1 | 0.12% | 1 | 3.23% |
| Total | 863 | 100.00% | 31 | 100.00% |
Overall Contributors
| Person | Tokens | Prop | Commits | CommitProp |
| Linus Torvalds (pre-git) | 452 | 39.61% | 3 | 7.50% |
| David Mosberger-Tang | 197 | 17.27% | 8 | 20.00% |
| Kautuk Consul | 92 | 8.06% | 1 | 2.50% |
| Nicholas Piggin | 85 | 7.45% | 3 | 7.50% |
| Linus Torvalds | 69 | 6.05% | 4 | 10.00% |
| Anil S Keshavamurthy | 58 | 5.08% | 2 | 5.00% |
| Christoph Hellwig | 34 | 2.98% | 2 | 5.00% |
| Johannes Weiner | 21 | 1.84% | 1 | 2.50% |
| Andrew Burgess | 21 | 1.84% | 1 | 2.50% |
| Jason Baron | 21 | 1.84% | 1 | 2.50% |
| Hugh Dickins | 20 | 1.75% | 1 | 2.50% |
| Tony Luck | 19 | 1.67% | 1 | 2.50% |
| Jan Beulich | 11 | 0.96% | 1 | 2.50% |
| Christoph Lameter | 9 | 0.79% | 1 | 2.50% |
| Kiyoshi Ueda | 8 | 0.70% | 1 | 2.50% |
| Paul Gortmaker | 6 | 0.53% | 2 | 5.00% |
| Shaohua Li | 4 | 0.35% | 1 | 2.50% |
| David Hildenbrand | 4 | 0.35% | 1 | 2.50% |
| Prasanna S. Panchamukhi | 4 | 0.35% | 1 | 2.50% |
| Björn Helgaas | 3 | 0.26% | 1 | 2.50% |
| Greg Kroah-Hartman | 1 | 0.09% | 1 | 2.50% |
| Ingo Molnar | 1 | 0.09% | 1 | 2.50% |
| Harvey Harrison | 1 | 0.09% | 1 | 2.50% |
| Total | 1141 | 100.00% | 40 | 100.00% |
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