500 lines
12 KiB
C
500 lines
12 KiB
C
/*
|
|
* linux/arch/unicore32/mm/fault.c
|
|
*
|
|
* Code specific to PKUnity SoC and UniCore ISA
|
|
*
|
|
* Copyright (C) 2001-2010 GUAN Xue-tao
|
|
*
|
|
* 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.
|
|
*/
|
|
#include <linux/module.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.h>
|
|
#include <linux/io.h>
|
|
|
|
#include <asm/pgtable.h>
|
|
#include <asm/tlbflush.h>
|
|
|
|
/*
|
|
* Fault status register encodings. We steal bit 31 for our own purposes.
|
|
*/
|
|
#define FSR_LNX_PF (1 << 31)
|
|
|
|
static inline int fsr_fs(unsigned int fsr)
|
|
{
|
|
/* xyabcde will be abcde+xy */
|
|
return (fsr & 31) + ((fsr & (3 << 5)) >> 5);
|
|
}
|
|
|
|
/*
|
|
* This is useful to dump out the page tables associated with
|
|
* 'addr' in mm 'mm'.
|
|
*/
|
|
void show_pte(struct mm_struct *mm, unsigned long addr)
|
|
{
|
|
pgd_t *pgd;
|
|
|
|
if (!mm)
|
|
mm = &init_mm;
|
|
|
|
printk(KERN_ALERT "pgd = %p\n", mm->pgd);
|
|
pgd = pgd_offset(mm, addr);
|
|
printk(KERN_ALERT "[%08lx] *pgd=%08lx", addr, pgd_val(*pgd));
|
|
|
|
do {
|
|
pmd_t *pmd;
|
|
pte_t *pte;
|
|
|
|
if (pgd_none(*pgd))
|
|
break;
|
|
|
|
if (pgd_bad(*pgd)) {
|
|
printk("(bad)");
|
|
break;
|
|
}
|
|
|
|
pmd = pmd_offset((pud_t *) pgd, addr);
|
|
if (PTRS_PER_PMD != 1)
|
|
printk(", *pmd=%08lx", pmd_val(*pmd));
|
|
|
|
if (pmd_none(*pmd))
|
|
break;
|
|
|
|
if (pmd_bad(*pmd)) {
|
|
printk("(bad)");
|
|
break;
|
|
}
|
|
|
|
/* We must not map this if we have highmem enabled */
|
|
if (PageHighMem(pfn_to_page(pmd_val(*pmd) >> PAGE_SHIFT)))
|
|
break;
|
|
|
|
pte = pte_offset_map(pmd, addr);
|
|
printk(", *pte=%08lx", pte_val(*pte));
|
|
pte_unmap(pte);
|
|
} while (0);
|
|
|
|
printk("\n");
|
|
}
|
|
|
|
/*
|
|
* Oops. The kernel tried to access some page that wasn't present.
|
|
*/
|
|
static void __do_kernel_fault(struct mm_struct *mm, unsigned long addr,
|
|
unsigned int fsr, struct pt_regs *regs)
|
|
{
|
|
/*
|
|
* Are we prepared to handle this kernel fault?
|
|
*/
|
|
if (fixup_exception(regs))
|
|
return;
|
|
|
|
/*
|
|
* No handler, we'll have to terminate things with extreme prejudice.
|
|
*/
|
|
bust_spinlocks(1);
|
|
printk(KERN_ALERT
|
|
"Unable to handle kernel %s at virtual address %08lx\n",
|
|
(addr < PAGE_SIZE) ? "NULL pointer dereference" :
|
|
"paging request", addr);
|
|
|
|
show_pte(mm, addr);
|
|
die("Oops", regs, fsr);
|
|
bust_spinlocks(0);
|
|
do_exit(SIGKILL);
|
|
}
|
|
|
|
/*
|
|
* Something tried to access memory that isn't in our memory map..
|
|
* User mode accesses just cause a SIGSEGV
|
|
*/
|
|
static void __do_user_fault(struct task_struct *tsk, unsigned long addr,
|
|
unsigned int fsr, unsigned int sig, int code,
|
|
struct pt_regs *regs)
|
|
{
|
|
struct siginfo si;
|
|
|
|
tsk->thread.address = addr;
|
|
tsk->thread.error_code = fsr;
|
|
tsk->thread.trap_no = 14;
|
|
si.si_signo = sig;
|
|
si.si_errno = 0;
|
|
si.si_code = code;
|
|
si.si_addr = (void __user *)addr;
|
|
force_sig_info(sig, &si, tsk);
|
|
}
|
|
|
|
void do_bad_area(unsigned long addr, unsigned int fsr, struct pt_regs *regs)
|
|
{
|
|
struct task_struct *tsk = current;
|
|
struct mm_struct *mm = tsk->active_mm;
|
|
|
|
/*
|
|
* If we are in kernel mode at this point, we
|
|
* have no context to handle this fault with.
|
|
*/
|
|
if (user_mode(regs))
|
|
__do_user_fault(tsk, addr, fsr, SIGSEGV, SEGV_MAPERR, regs);
|
|
else
|
|
__do_kernel_fault(mm, addr, fsr, regs);
|
|
}
|
|
|
|
#define VM_FAULT_BADMAP 0x010000
|
|
#define VM_FAULT_BADACCESS 0x020000
|
|
|
|
/*
|
|
* Check that the permissions on the VMA allow for the fault which occurred.
|
|
* If we encountered a write fault, we must have write permission, otherwise
|
|
* we allow any permission.
|
|
*/
|
|
static inline bool access_error(unsigned int fsr, struct vm_area_struct *vma)
|
|
{
|
|
unsigned int mask = VM_READ | VM_WRITE | VM_EXEC;
|
|
|
|
if (!(fsr ^ 0x12)) /* write? */
|
|
mask = VM_WRITE;
|
|
if (fsr & FSR_LNX_PF)
|
|
mask = VM_EXEC;
|
|
|
|
return vma->vm_flags & mask ? false : true;
|
|
}
|
|
|
|
static int __do_pf(struct mm_struct *mm, unsigned long addr, unsigned int fsr,
|
|
unsigned int 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:
|
|
if (access_error(fsr, vma)) {
|
|
fault = VM_FAULT_BADACCESS;
|
|
goto out;
|
|
}
|
|
|
|
/*
|
|
* 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(mm, vma, addr & PAGE_MASK, flags);
|
|
return fault;
|
|
|
|
check_stack:
|
|
if (vma->vm_flags & VM_GROWSDOWN && !expand_stack(vma, addr))
|
|
goto good_area;
|
|
out:
|
|
return fault;
|
|
}
|
|
|
|
static int do_pf(unsigned long addr, unsigned int fsr, struct pt_regs *regs)
|
|
{
|
|
struct task_struct *tsk;
|
|
struct mm_struct *mm;
|
|
int fault, sig, code;
|
|
unsigned int flags = FAULT_FLAG_ALLOW_RETRY | FAULT_FLAG_KILLABLE;
|
|
|
|
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))
|
|
flags |= FAULT_FLAG_USER;
|
|
if (!(fsr ^ 0x12))
|
|
flags |= FAULT_FLAG_WRITE;
|
|
|
|
/*
|
|
* 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->UCreg_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->UCreg_pc))
|
|
goto no_context;
|
|
#endif
|
|
}
|
|
|
|
fault = __do_pf(mm, addr, fsr, flags, tsk);
|
|
|
|
/* 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 ((fault & VM_FAULT_RETRY) && fatal_signal_pending(current))
|
|
return 0;
|
|
|
|
if (!(fault & VM_FAULT_ERROR) && (flags & FAULT_FLAG_ALLOW_RETRY)) {
|
|
if (fault & VM_FAULT_MAJOR)
|
|
tsk->maj_flt++;
|
|
else
|
|
tsk->min_flt++;
|
|
if (fault & VM_FAULT_RETRY) {
|
|
/* Clear FAULT_FLAG_ALLOW_RETRY to avoid any risk
|
|
* of starvation. */
|
|
flags &= ~FAULT_FLAG_ALLOW_RETRY;
|
|
goto retry;
|
|
}
|
|
}
|
|
|
|
up_read(&mm->mmap_sem);
|
|
|
|
/*
|
|
* Handle the "normal" case first - VM_FAULT_MAJOR
|
|
*/
|
|
if (likely(!(fault &
|
|
(VM_FAULT_ERROR | VM_FAULT_BADMAP | VM_FAULT_BADACCESS))))
|
|
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 {
|
|
/*
|
|
* 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, fsr, sig, code, regs);
|
|
return 0;
|
|
|
|
no_context:
|
|
__do_kernel_fault(mm, addr, fsr, regs);
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* First Level Translation Fault Handler
|
|
*
|
|
* We enter here because the first level page table doesn't contain
|
|
* a valid entry for the address.
|
|
*
|
|
* If the address is in kernel space (>= TASK_SIZE), then we are
|
|
* probably faulting in the vmalloc() area.
|
|
*
|
|
* If the init_task's first level page tables contains the relevant
|
|
* entry, we copy the it to this task. If not, we send the process
|
|
* a signal, fixup the exception, or oops the kernel.
|
|
*
|
|
* 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.
|
|
*/
|
|
static int do_ifault(unsigned long addr, unsigned int fsr, struct pt_regs *regs)
|
|
{
|
|
unsigned int index;
|
|
pgd_t *pgd, *pgd_k;
|
|
pmd_t *pmd, *pmd_k;
|
|
|
|
if (addr < TASK_SIZE)
|
|
return do_pf(addr, fsr, regs);
|
|
|
|
if (user_mode(regs))
|
|
goto bad_area;
|
|
|
|
index = pgd_index(addr);
|
|
|
|
pgd = cpu_get_pgd() + index;
|
|
pgd_k = init_mm.pgd + index;
|
|
|
|
if (pgd_none(*pgd_k))
|
|
goto bad_area;
|
|
|
|
pmd_k = pmd_offset((pud_t *) pgd_k, addr);
|
|
pmd = pmd_offset((pud_t *) pgd, addr);
|
|
|
|
if (pmd_none(*pmd_k))
|
|
goto bad_area;
|
|
|
|
set_pmd(pmd, *pmd_k);
|
|
flush_pmd_entry(pmd);
|
|
return 0;
|
|
|
|
bad_area:
|
|
do_bad_area(addr, fsr, regs);
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* This abort handler always returns "fault".
|
|
*/
|
|
static int do_bad(unsigned long addr, unsigned int fsr, struct pt_regs *regs)
|
|
{
|
|
return 1;
|
|
}
|
|
|
|
static int do_good(unsigned long addr, unsigned int fsr, struct pt_regs *regs)
|
|
{
|
|
unsigned int res1, res2;
|
|
|
|
printk("dabt exception but no error!\n");
|
|
|
|
__asm__ __volatile__(
|
|
"mff %0,f0\n"
|
|
"mff %1,f1\n"
|
|
: "=r"(res1), "=r"(res2)
|
|
:
|
|
: "memory");
|
|
|
|
printk(KERN_EMERG "r0 :%08x r1 :%08x\n", res1, res2);
|
|
panic("shut up\n");
|
|
return 0;
|
|
}
|
|
|
|
static struct fsr_info {
|
|
int (*fn) (unsigned long addr, unsigned int fsr, struct pt_regs *regs);
|
|
int sig;
|
|
int code;
|
|
const char *name;
|
|
} fsr_info[] = {
|
|
/*
|
|
* The following are the standard Unicore-I and UniCore-II aborts.
|
|
*/
|
|
{ do_good, SIGBUS, 0, "no error" },
|
|
{ do_bad, SIGBUS, BUS_ADRALN, "alignment exception" },
|
|
{ do_bad, SIGBUS, BUS_OBJERR, "external exception" },
|
|
{ do_bad, SIGBUS, 0, "burst operation" },
|
|
{ do_bad, SIGBUS, 0, "unknown 00100" },
|
|
{ do_ifault, SIGSEGV, SEGV_MAPERR, "2nd level pt non-exist"},
|
|
{ do_bad, SIGBUS, 0, "2nd lvl large pt non-exist" },
|
|
{ do_bad, SIGBUS, 0, "invalid pte" },
|
|
{ do_pf, SIGSEGV, SEGV_MAPERR, "page miss" },
|
|
{ do_bad, SIGBUS, 0, "middle page miss" },
|
|
{ do_bad, SIGBUS, 0, "large page miss" },
|
|
{ do_pf, SIGSEGV, SEGV_MAPERR, "super page (section) miss" },
|
|
{ do_bad, SIGBUS, 0, "unknown 01100" },
|
|
{ do_bad, SIGBUS, 0, "unknown 01101" },
|
|
{ do_bad, SIGBUS, 0, "unknown 01110" },
|
|
{ do_bad, SIGBUS, 0, "unknown 01111" },
|
|
{ do_bad, SIGBUS, 0, "addr: up 3G or IO" },
|
|
{ do_pf, SIGSEGV, SEGV_ACCERR, "read unreadable addr" },
|
|
{ do_pf, SIGSEGV, SEGV_ACCERR, "write unwriteable addr"},
|
|
{ do_pf, SIGSEGV, SEGV_ACCERR, "exec unexecutable addr"},
|
|
{ do_bad, SIGBUS, 0, "unknown 10100" },
|
|
{ do_bad, SIGBUS, 0, "unknown 10101" },
|
|
{ do_bad, SIGBUS, 0, "unknown 10110" },
|
|
{ do_bad, SIGBUS, 0, "unknown 10111" },
|
|
{ do_bad, SIGBUS, 0, "unknown 11000" },
|
|
{ do_bad, SIGBUS, 0, "unknown 11001" },
|
|
{ do_bad, SIGBUS, 0, "unknown 11010" },
|
|
{ do_bad, SIGBUS, 0, "unknown 11011" },
|
|
{ do_bad, SIGBUS, 0, "unknown 11100" },
|
|
{ do_bad, SIGBUS, 0, "unknown 11101" },
|
|
{ do_bad, SIGBUS, 0, "unknown 11110" },
|
|
{ do_bad, SIGBUS, 0, "unknown 11111" }
|
|
};
|
|
|
|
void __init hook_fault_code(int nr,
|
|
int (*fn) (unsigned long, unsigned int, struct pt_regs *),
|
|
int sig, int code, const char *name)
|
|
{
|
|
if (nr < 0 || nr >= ARRAY_SIZE(fsr_info))
|
|
BUG();
|
|
|
|
fsr_info[nr].fn = fn;
|
|
fsr_info[nr].sig = sig;
|
|
fsr_info[nr].code = code;
|
|
fsr_info[nr].name = name;
|
|
}
|
|
|
|
/*
|
|
* Dispatch a data abort to the relevant handler.
|
|
*/
|
|
asmlinkage void do_DataAbort(unsigned long addr, unsigned int fsr,
|
|
struct pt_regs *regs)
|
|
{
|
|
const struct fsr_info *inf = fsr_info + fsr_fs(fsr);
|
|
struct siginfo info;
|
|
|
|
if (!inf->fn(addr, fsr & ~FSR_LNX_PF, regs))
|
|
return;
|
|
|
|
printk(KERN_ALERT "Unhandled fault: %s (0x%03x) at 0x%08lx\n",
|
|
inf->name, fsr, addr);
|
|
|
|
info.si_signo = inf->sig;
|
|
info.si_errno = 0;
|
|
info.si_code = inf->code;
|
|
info.si_addr = (void __user *)addr;
|
|
uc32_notify_die("", regs, &info, fsr, 0);
|
|
}
|
|
|
|
asmlinkage void do_PrefetchAbort(unsigned long addr,
|
|
unsigned int ifsr, struct pt_regs *regs)
|
|
{
|
|
const struct fsr_info *inf = fsr_info + fsr_fs(ifsr);
|
|
struct siginfo info;
|
|
|
|
if (!inf->fn(addr, ifsr | FSR_LNX_PF, regs))
|
|
return;
|
|
|
|
printk(KERN_ALERT "Unhandled prefetch abort: %s (0x%03x) at 0x%08lx\n",
|
|
inf->name, ifsr, addr);
|
|
|
|
info.si_signo = inf->sig;
|
|
info.si_errno = 0;
|
|
info.si_code = inf->code;
|
|
info.si_addr = (void __user *)addr;
|
|
uc32_notify_die("", regs, &info, ifsr, 0);
|
|
}
|