284 lines
7.3 KiB
C
284 lines
7.3 KiB
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);
|
|
|
|
/*
|
|
* 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);
|
|
}
|
|
|
|
# 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;
|
|
unsigned long mask;
|
|
vm_fault_t 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 (kprobe_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)) {
|
|
force_sig_fault(signal, code, (void __user *) address,
|
|
0, __ISR_VALID, isr);
|
|
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)
|
|
make_task_dead(SIGKILL);
|
|
return;
|
|
|
|
out_of_memory:
|
|
up_read(&mm->mmap_sem);
|
|
if (!user_mode(regs))
|
|
goto no_context;
|
|
pagefault_out_of_memory();
|
|
}
|