- 根目录:
- arch
- tile
- mm
- fault.c
/*
* Copyright 2010 Tilera Corporation. All Rights Reserved.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation, version 2.
*
* This program is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or
* NON INFRINGEMENT. See the GNU General Public License for
* more details.
*
* From i386 code copyright (C) 1995 Linus Torvalds
*/
#include <linux/signal.h>
#include <linux/sched.h>
#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/string.h>
#include <linux/types.h>
#include <linux/ptrace.h>
#include <linux/mman.h>
#include <linux/mm.h>
#include <linux/smp.h>
#include <linux/interrupt.h>
#include <linux/init.h>
#include <linux/tty.h>
#include <linux/vt_kern.h> /* For unblank_screen() */
#include <linux/highmem.h>
#include <linux/module.h>
#include <linux/kprobes.h>
#include <linux/hugetlb.h>
#include <linux/syscalls.h>
#include <linux/uaccess.h>
#include <linux/kdebug.h>
#include <asm/pgalloc.h>
#include <asm/sections.h>
#include <asm/traps.h>
#include <asm/syscalls.h>
#include <arch/interrupts.h>
static noinline void force_sig_info_fault(const char *type, int si_signo,
int si_code, unsigned long address,
int fault_num,
struct task_struct *tsk,
struct pt_regs *regs)
{
siginfo_t info;
if (unlikely(tsk->pid < 2)) {
panic("Signal %d (code %d) at %#lx sent to %s!",
si_signo, si_code & 0xffff, address,
is_idle_task(tsk) ? "the idle task" : "init");
}
info.si_signo = si_signo;
info.si_errno = 0;
info.si_code = si_code;
info.si_addr = (void __user *)address;
info.si_trapno = fault_num;
trace_unhandled_signal(type, regs, address, si_signo);
force_sig_info(si_signo, &info, tsk);
}
#ifndef __tilegx__
/*
* Synthesize the fault a PL0 process would get by doing a word-load of
* an unaligned address or a high kernel address.
*/
SYSCALL_DEFINE1(cmpxchg_badaddr, unsigned long, address)
{
struct pt_regs *regs = current_pt_regs();
if (address >= PAGE_OFFSET)
force_sig_info_fault("atomic segfault", SIGSEGV, SEGV_MAPERR,
address, INT_DTLB_MISS, current, regs);
else
force_sig_info_fault("atomic alignment fault", SIGBUS,
BUS_ADRALN, address,
INT_UNALIGN_DATA, current, regs);
/*
* Adjust pc to point at the actual instruction, which is unusual
* for syscalls normally, but is appropriate when we are claiming
* that a syscall swint1 caused a page fault or bus error.
*/
regs->pc -= 8;
/*
* Mark this as a caller-save interrupt, like a normal page fault,
* so that when we go through the signal handler path we will
* properly restore r0, r1, and r2 for the signal handler arguments.
*/
regs->flags |= PT_FLAGS_CALLER_SAVES;
return 0;
}
#endif
static inline pmd_t *vmalloc_sync_one(pgd_t *pgd, unsigned long address)
{
unsigned index = pgd_index(address);
pgd_t *pgd_k;
pud_t *pud, *pud_k;
pmd_t *pmd, *pmd_k;
pgd += index;
pgd_k = init_mm.pgd + index;
if (!pgd_present(*pgd_k))
return NULL;
pud = pud_offset(pgd, address);
pud_k = pud_offset(pgd_k, address);
if (!pud_present(*pud_k))
return NULL;
pmd = pmd_offset(pud, address);
pmd_k = pmd_offset(pud_k, address);
if (!pmd_present(*pmd_k))
return NULL;
if (!pmd_present(*pmd))
set_pmd(pmd, *pmd_k);
else
BUG_ON(pmd_ptfn(*pmd) != pmd_ptfn(*pmd_k));
return pmd_k;
}
/*
* Handle a fault on the vmalloc area.
*/
static inline int vmalloc_fault(pgd_t *pgd, unsigned long address)
{
pmd_t *pmd_k;
pte_t *pte_k;
/* Make sure we are in vmalloc area */
if (!(address >= VMALLOC_START && address < VMALLOC_END))
return -1;
/*
* Synchronize this task's top level page-table
* with the 'reference' page table.
*/
pmd_k = vmalloc_sync_one(pgd, address);
if (!pmd_k)
return -1;
pte_k = pte_offset_kernel(pmd_k, address);
if (!pte_present(*pte_k))
return -1;
return 0;
}
/* Wait until this PTE has completed migration. */
static void wait_for_migration(pte_t *pte)
{
if (pte_migrating(*pte)) {
/*
* Wait until the migrater fixes up this pte.
* We scale the loop count by the clock rate so we'll wait for
* a few seconds here.
*/
int retries = 0;
int bound = get_clock_rate();
while (pte_migrating(*pte)) {
barrier();
if (++retries > bound)
panic("Hit migrating PTE (%#llx) and"
" page PFN %#lx still migrating",
pte->val, pte_pfn(*pte));
}
}
}
/*
* It's not generally safe to use "current" to get the page table pointer,
* since we might be running an oprofile interrupt in the middle of a
* task switch.
*/
static pgd_t *get_current_pgd(void)
{
HV_Context ctx = hv_inquire_context();
unsigned long pgd_pfn = ctx.page_table >> PAGE_SHIFT;
struct page *pgd_page = pfn_to_page(pgd_pfn);
BUG_ON(PageHighMem(pgd_page));
return (pgd_t *) __va(ctx.page_table);
}
/*
* We can receive a page fault from a migrating PTE at any time.
* Handle it by just waiting until the fault resolves.
*
* It's also possible to get a migrating kernel PTE that resolves
* itself during the downcall from hypervisor to Linux. We just check
* here to see if the PTE seems valid, and if so we retry it.
*
* NOTE! We MUST NOT take any locks for this case. We may be in an
* interrupt or a critical region, and must do as little as possible.
* Similarly, we can't use atomic ops here, since we may be handling a
* fault caused by an atomic op access.
*
* If we find a migrating PTE while we're in an NMI context, and we're
* at a PC that has a registered exception handler, we don't wait,
* since this thread may (e.g.) have been interrupted while migrating
* its own stack, which would then cause us to self-deadlock.
*/
static int handle_migrating_pte(pgd_t *pgd, int fault_num,
unsigned long address, unsigned long pc,
int is_kernel_mode, int write)
{
pud_t *pud;
pmd_t *pmd;
pte_t *pte;
pte_t pteval;
if (pgd_addr_invalid(address))
return 0;
pgd += pgd_index(address);
pud = pud_offset(pgd, address);
if (!pud || !pud_present(*pud))
return 0;
pmd = pmd_offset(pud, address);
if (!pmd || !pmd_present(*pmd))
return 0;
pte = pmd_huge_page(*pmd) ? ((pte_t *)pmd) :
pte_offset_kernel(pmd, address);
pteval = *pte;
if (pte_migrating(pteval)) {
if (in_nmi() && search_exception_tables(pc))
return 0;
wait_for_migration(pte);
return 1;
}
if (!is_kernel_mode || !pte_present(pteval))
return 0;
if (fault_num == INT_ITLB_MISS) {
if (pte_exec(pteval))
return 1;
} else if (write) {
if (pte_write(pteval))
return 1;
} else {
if (pte_read(pteval))
return 1;
}
return 0;
}
/*
* This routine is responsible for faulting in user pages.
* It passes the work off to one of the appropriate routines.
* It returns true if the fault was successfully handled.
*/
static int handle_page_fault(struct pt_regs *regs,
int fault_num,
int is_page_fault,
unsigned long address,
int write)
{
struct task_struct *tsk;
struct mm_struct *mm;
struct vm_area_struct *vma;
unsigned long stack_offset;
int fault;
int si_code;
int is_kernel_mode;
pgd_t *pgd;
unsigned int flags;
/* on TILE, protection faults are always writes */
if (!is_page_fault)
write = 1;
flags = FAULT_FLAG_ALLOW_RETRY | FAULT_FLAG_KILLABLE;
is_kernel_mode = !user_mode(regs);
tsk = validate_current();
/*
* Check to see if we might be overwriting the stack, and bail
* out if so. The page fault code is a relatively likely
* place to get trapped in an infinite regress, and once we
* overwrite the whole stack, it becomes very hard to recover.
*/
stack_offset = stack_pointer & (THREAD_SIZE-1);
if (stack_offset < THREAD_SIZE / 8) {
pr_alert("Potential stack overrun: sp %#lx\n",
stack_pointer);
show_regs(regs);
pr_alert("Killing current process %d/%s\n",
tsk->pid, tsk->comm);
do_group_exit(SIGKILL);
}
/*
* Early on, we need to check for migrating PTE entries;
* see homecache.c. If we find a migrating PTE, we wait until
* the backing page claims to be done migrating, then we proceed.
* For kernel PTEs, we rewrite the PTE and return and retry.
* Otherwise, we treat the fault like a normal "no PTE" fault,
* rather than trying to patch up the existing PTE.
*/
pgd = get_current_pgd();
if (handle_migrating_pte(pgd, fault_num, address, regs->pc,
is_kernel_mode, write))
return 1;
si_code = SEGV_MAPERR;
/*
* 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.
*
* This verifies that the fault happens in kernel space
* and that the fault was not a protection fault.
*/
if (unlikely(address >= TASK_SIZE &&
!is_arch_mappable_range(address, 0))) {
if (is_kernel_mode && is_page_fault &&
vmalloc_fault(pgd, address) >= 0)
return 1;
/*
* Don't take the mm semaphore here. If we fixup a prefetch
* fault we could otherwise deadlock.
*/
mm = NULL; /* happy compiler */
vma = NULL;
goto bad_area_nosemaphore;
}
/*
* If we're trying to touch user-space addresses, we must
* be either at PL0, or else with interrupts enabled in the
* kernel, so either way we can re-enable interrupts here
* unless we are doing atomic access to user space with
* interrupts disabled.
*/
if (!(regs->flags & PT_FLAGS_DISABLE_IRQ))
local_irq_enable();
mm = tsk->mm;
/*
* If we're in an interrupt, have no user context or are running in an
* atomic region then we must not take the fault.
*/
if (in_atomic() || !mm) {
vma = NULL; /* happy compiler */
goto bad_area_nosemaphore;
}
if (!is_kernel_mode)
flags |= FAULT_FLAG_USER;
/*
* When running in the kernel we expect faults to occur only to
* addresses in user space. All other faults represent errors in the
* kernel and should generate an OOPS. Unfortunately, in the case of an
* erroneous fault occurring in a code path which already holds mmap_sem
* we will deadlock attempting to validate the fault against the
* address space. Luckily the kernel only validly references user
* space from well defined areas of code, which are listed in the
* exceptions table.
*
* As the vast majority of faults will be valid we will only perform
* the source reference check when there is a possibility of a deadlock.
* Attempt to lock the address space, if we cannot we then validate the
* source. If this is invalid we can skip the address space check,
* thus avoiding the deadlock.
*/
if (!down_read_trylock(&mm->mmap_sem)) {
if (is_kernel_mode &&
!search_exception_tables(regs->pc)) {
vma = NULL; /* happy compiler */
goto bad_area_nosemaphore;
}
retry:
down_read(&mm->mmap_sem);
}
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 (regs->sp < PAGE_OFFSET) {
/*
* accessing the stack below sp is always a bug.
*/
if (address < 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;
if (fault_num == INT_ITLB_MISS) {
if (!(vma->vm_flags & VM_EXEC))
goto bad_area;
} else if (write) {
#ifdef TEST_VERIFY_AREA
if (!is_page_fault && regs->cs == KERNEL_CS)
pr_err("WP fault at "REGFMT"\n", regs->eip);
#endif
if (!(vma->vm_flags & VM_WRITE))
goto bad_area;
flags |= FAULT_FLAG_WRITE;
} else {
if (!is_page_fault || !(vma->vm_flags & VM_READ))
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(mm, vma, address, flags);
if ((fault & VM_FAULT_RETRY) && fatal_signal_pending(current))
return 0;
if (unlikely(fault & VM_FAULT_ERROR)) {
if (fault & VM_FAULT_OOM)
goto out_of_memory;
else if (fault & VM_FAULT_SIGBUS)
goto do_sigbus;
BUG();
}
if (flags & FAULT_FLAG_ALLOW_RETRY) {
if (fault & VM_FAULT_MAJOR)
tsk->maj_flt++;
else
tsk->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;
}
}
#if CHIP_HAS_TILE_DMA()
/* If this was a DMA TLB fault, restart the DMA engine. */
switch (fault_num) {
case INT_DMATLB_MISS:
case INT_DMATLB_MISS_DWNCL:
case INT_DMATLB_ACCESS:
case INT_DMATLB_ACCESS_DWNCL:
__insn_mtspr(SPR_DMA_CTR, SPR_DMA_CTR__REQUEST_MASK);
break;
}
#endif
up_read(&mm->mmap_sem);
return 1;
/*
* 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:
up_read(&mm->mmap_sem);
bad_area_nosemaphore:
/* User mode accesses just cause a SIGSEGV */
if (!is_kernel_mode) {
/*
* It's possible to have interrupts off here.
*/
local_irq_enable();
force_sig_info_fault("segfault", SIGSEGV, si_code, address,
fault_num, tsk, regs);
return 0;
}
no_context:
/* Are we prepared to handle this kernel fault? */
if (fixup_exception(regs))
return 0;
/*
* Oops. The kernel tried to access some bad page. We'll have to
* terminate things with extreme prejudice.
*/
bust_spinlocks(1);
/* FIXME: no lookup_address() yet */
#ifdef SUPPORT_LOOKUP_ADDRESS
if (fault_num == INT_ITLB_MISS) {
pte_t *pte = lookup_address(address);
if (pte && pte_present(*pte) && !pte_exec_kernel(*pte))
pr_crit("kernel tried to execute"
" non-executable page - exploit attempt?"
" (uid: %d)\n", current->uid);
}
#endif
if (address < PAGE_SIZE)
pr_alert("Unable to handle kernel NULL pointer dereference\n");
else
pr_alert("Unable to handle kernel paging request\n");
pr_alert(" at virtual address "REGFMT", pc "REGFMT"\n",
address, regs->pc);
show_regs(regs);
if (unlikely(tsk->pid < 2)) {
panic("Kernel page fault running %s!",
is_idle_task(tsk) ? "the idle task" : "init");
}
/*
* More FIXME: we should probably copy the i386 here and
* implement a generic die() routine. Not today.
*/
#ifdef SUPPORT_DIE
die("Oops", regs);
#endif
bust_spinlocks(1);
do_group_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:
up_read(&mm->mmap_sem);
if (is_kernel_mode)
goto no_context;
pagefault_out_of_memory();
return 0;
do_sigbus:
up_read(&mm->mmap_sem);
/* Kernel mode? Handle exceptions or die */
if (is_kernel_mode)
goto no_context;
force_sig_info_fault("bus error", SIGBUS, BUS_ADRERR, address,
fault_num, tsk, regs);
return 0;
}
#ifndef __tilegx__
/* We must release ICS before panicking or we won't get anywhere. */
#define ics_panic(fmt, ...) do { \
__insn_mtspr(SPR_INTERRUPT_CRITICAL_SECTION, 0); \
panic(fmt, __VA_ARGS__); \
} while (0)
/*
* When we take an ITLB or DTLB fault or access violation in the
* supervisor while the critical section bit is set, the hypervisor is
* reluctant to write new values into the EX_CONTEXT_K_x registers,
* since that might indicate we have not yet squirreled the SPR
* contents away and can thus safely take a recursive interrupt.
* Accordingly, the hypervisor passes us the PC via SYSTEM_SAVE_K_2.
*
* Note that this routine is called before homecache_tlb_defer_enter(),
* which means that we can properly unlock any atomics that might
* be used there (good), but also means we must be very sensitive
* to not touch any data structures that might be located in memory
* that could migrate, as we could be entering the kernel on a dataplane
* cpu that has been deferring kernel TLB updates. This means, for
* example, that we can't migrate init_mm or its pgd.
*/
struct intvec_state do_page_fault_ics(struct pt_regs *regs, int fault_num,
unsigned long address,
unsigned long info)
{
unsigned long pc = info & ~1;
int write = info & 1;
pgd_t *pgd = get_current_pgd();
/* Retval is 1 at first since we will handle the fault fully. */
struct intvec_state state = {
do_page_fault, fault_num, address, write, 1
};
/* Validate that we are plausibly in the right routine. */
if ((pc & 0x7) != 0 || pc < PAGE_OFFSET ||
(fault_num != INT_DTLB_MISS &&
fault_num != INT_DTLB_ACCESS)) {
unsigned long old_pc = regs->pc;
regs->pc = pc;
ics_panic("Bad ICS page fault args:"
" old PC %#lx, fault %d/%d at %#lx\n",
old_pc, fault_num, write, address);
}
/* We might be faulting on a vmalloc page, so check that first. */
if (fault_num != INT_DTLB_ACCESS && vmalloc_fault(pgd, address) >= 0)
return state;
/*
* If we faulted with ICS set in sys_cmpxchg, we are providing
* a user syscall service that should generate a signal on
* fault. We didn't set up a kernel stack on initial entry to
* sys_cmpxchg, but instead had one set up by the fault, which
* (because sys_cmpxchg never releases ICS) came to us via the
* SYSTEM_SAVE_K_2 mechanism, and thus EX_CONTEXT_K_[01] are
* still referencing the original user code. We release the
* atomic lock and rewrite pt_regs so that it appears that we
* came from user-space directly, and after we finish the
* fault we'll go back to user space and re-issue the swint.
* This way the backtrace information is correct if we need to
* emit a stack dump at any point while handling this.
*
* Must match register use in sys_cmpxchg().
*/
if (pc >= (unsigned long) sys_cmpxchg &&
pc < (unsigned long) __sys_cmpxchg_end) {
#ifdef CONFIG_SMP
/* Don't unlock before we could have locked. */
if (pc >= (unsigned long)__sys_cmpxchg_grab_lock) {
int *lock_ptr = (int *)(regs->regs[ATOMIC_LOCK_REG]);
__atomic_fault_unlock(lock_ptr);
}
#endif
regs->sp = regs->regs[27];
}
/*
* We can also fault in the atomic assembly, in which
* case we use the exception table to do the first-level fixup.
* We may re-fixup again in the real fault handler if it
* turns out the faulting address is just bad, and not,
* for example, migrating.
*/
else if (pc >= (unsigned long) __start_atomic_asm_code &&
pc < (unsigned long) __end_atomic_asm_code) {
const struct exception_table_entry *fixup;
#ifdef CONFIG_SMP
/* Unlock the atomic lock. */
int *lock_ptr = (int *)(regs->regs[ATOMIC_LOCK_REG]);
__atomic_fault_unlock(lock_ptr);
#endif
fixup = search_exception_tables(pc);
if (!fixup)
ics_panic("ICS atomic fault not in table:"
" PC %#lx, fault %d", pc, fault_num);
regs->pc = fixup->fixup;
regs->ex1 = PL_ICS_EX1(KERNEL_PL, 0);
}
/*
* Now that we have released the atomic lock (if necessary),
* it's safe to spin if the PTE that caused the fault was migrating.
*/
if (fault_num == INT_DTLB_ACCESS)
write = 1;
if (handle_migrating_pte(pgd, fault_num, address, pc, 1, write))
return state;
/* Return zero so that we continue on with normal fault handling. */
state.retval = 0;
return state;
}
#endif /* !__tilegx__ */
/*
* This routine handles page faults. It determines the address, and the
* problem, and then passes it handle_page_fault() for normal DTLB and
* ITLB issues, and for DMA or SN processor faults when we are in user
* space. For the latter, if we're in kernel mode, we just save the
* interrupt away appropriately and return immediately. We can't do
* page faults for user code while in kernel mode.
*/
void do_page_fault(struct pt_regs *regs, int fault_num,
unsigned long address, unsigned long write)
{
int is_page_fault;
#ifdef CONFIG_KPROBES
/*
* This is to notify the fault handler of the kprobes. The
* exception code is redundant as it is also carried in REGS,
* but we pass it anyhow.
*/
if (notify_die(DIE_PAGE_FAULT, "page fault", regs, -1,
regs->faultnum, SIGSEGV) == NOTIFY_STOP)
return;
#endif
#ifdef __tilegx__
/*
* We don't need early do_page_fault_ics() support, since unlike
* Pro we don't need to worry about unlocking the atomic locks.
* There is only one current case in GX where we touch any memory
* under ICS other than our own kernel stack, and we handle that
* here. (If we crash due to trying to touch our own stack,
* we're in too much trouble for C code to help out anyway.)
*/
if (write & ~1) {
unsigned long pc = write & ~1;
if (pc >= (unsigned long) __start_unalign_asm_code &&
pc < (unsigned long) __end_unalign_asm_code) {
struct thread_info *ti = current_thread_info();
/*
* Our EX_CONTEXT is still what it was from the
* initial unalign exception, but now we've faulted
* on the JIT page. We would like to complete the
* page fault however is appropriate, and then retry
* the instruction that caused the unalign exception.
* Our state has been "corrupted" by setting the low
* bit in "sp", and stashing r0..r3 in the
* thread_info area, so we revert all of that, then
* continue as if this were a normal page fault.
*/
regs->sp &= ~1UL;
regs->regs[0] = ti->unalign_jit_tmp[0];
regs->regs[1] = ti->unalign_jit_tmp[1];
regs->regs[2] = ti->unalign_jit_tmp[2];
regs->regs[3] = ti->unalign_jit_tmp[3];
write &= 1;
} else {
pr_alert("%s/%d: ICS set at page fault at %#lx: %#lx\n",
current->comm, current->pid, pc, address);
show_regs(regs);
do_group_exit(SIGKILL);
return;
}
}
#else
/* This case should have been handled by do_page_fault_ics(). */
BUG_ON(write & ~1);
#endif
#if CHIP_HAS_TILE_DMA()
/*
* If it's a DMA fault, suspend the transfer while we're
* handling the miss; we'll restart after it's handled. If we
* don't suspend, it's possible that this process could swap
* out and back in, and restart the engine since the DMA is
* still 'running'.
*/
if (fault_num == INT_DMATLB_MISS ||
fault_num == INT_DMATLB_ACCESS ||
fault_num == INT_DMATLB_MISS_DWNCL ||
fault_num == INT_DMATLB_ACCESS_DWNCL) {
__insn_mtspr(SPR_DMA_CTR, SPR_DMA_CTR__SUSPEND_MASK);
while (__insn_mfspr(SPR_DMA_USER_STATUS) &
SPR_DMA_STATUS__BUSY_MASK)
;
}
#endif
/* Validate fault num and decide if this is a first-time page fault. */
switch (fault_num) {
case INT_ITLB_MISS:
case INT_DTLB_MISS:
#if CHIP_HAS_TILE_DMA()
case INT_DMATLB_MISS:
case INT_DMATLB_MISS_DWNCL:
#endif
is_page_fault = 1;
break;
case INT_DTLB_ACCESS:
#if CHIP_HAS_TILE_DMA()
case INT_DMATLB_ACCESS:
case INT_DMATLB_ACCESS_DWNCL:
#endif
is_page_fault = 0;
break;
default:
panic("Bad fault number %d in do_page_fault", fault_num);
}
#if CHIP_HAS_TILE_DMA()
if (!user_mode(regs)) {
struct async_tlb *async;
switch (fault_num) {
#if CHIP_HAS_TILE_DMA()
case INT_DMATLB_MISS:
case INT_DMATLB_ACCESS:
case INT_DMATLB_MISS_DWNCL:
case INT_DMATLB_ACCESS_DWNCL:
async = ¤t->thread.dma_async_tlb;
break;
#endif
default:
async = NULL;
}
if (async) {
/*
* No vmalloc check required, so we can allow
* interrupts immediately at this point.
*/
local_irq_enable();
set_thread_flag(TIF_ASYNC_TLB);
if (async->fault_num != 0) {
panic("Second async fault %d;"
" old fault was %d (%#lx/%ld)",
fault_num, async->fault_num,
address, write);
}
BUG_ON(fault_num == 0);
async->fault_num = fault_num;
async->is_fault = is_page_fault;
async->is_write = write;
async->address = address;
return;
}
}
#endif
handle_page_fault(regs, fault_num, is_page_fault, address, write);
}
#if CHIP_HAS_TILE_DMA()
/*
* This routine effectively re-issues asynchronous page faults
* when we are returning to user space.
*/
void do_async_page_fault(struct pt_regs *regs)
{
struct async_tlb *async = ¤t->thread.dma_async_tlb;
/*
* Clear thread flag early. If we re-interrupt while processing
* code here, we will reset it and recall this routine before
* returning to user space.
*/
clear_thread_flag(TIF_ASYNC_TLB);
if (async->fault_num) {
/*
* Clear async->fault_num before calling the page-fault
* handler so that if we re-interrupt before returning
* from the function we have somewhere to put the
* information from the new interrupt.
*/
int fault_num = async->fault_num;
async->fault_num = 0;
handle_page_fault(regs, fault_num, async->is_fault,
async->address, async->is_write);
}
}
#endif /* CHIP_HAS_TILE_DMA() */
void vmalloc_sync_all(void)
{
#ifdef __tilegx__
/* Currently all L1 kernel pmd's are static and shared. */
BUILD_BUG_ON(pgd_index(VMALLOC_END - PAGE_SIZE) !=
pgd_index(VMALLOC_START));
#else
/*
* Note that races in the updates of insync and start aren't
* problematic: insync can only get set bits added, and updates to
* start are only improving performance (without affecting correctness
* if undone).
*/
static DECLARE_BITMAP(insync, PTRS_PER_PGD);
static unsigned long start = PAGE_OFFSET;
unsigned long address;
BUILD_BUG_ON(PAGE_OFFSET & ~PGDIR_MASK);
for (address = start; address >= PAGE_OFFSET; address += PGDIR_SIZE) {
if (!test_bit(pgd_index(address), insync)) {
unsigned long flags;
struct list_head *pos;
spin_lock_irqsave(&pgd_lock, flags);
list_for_each(pos, &pgd_list)
if (!vmalloc_sync_one(list_to_pgd(pos),
address)) {
/* Must be at first entry in list. */
BUG_ON(pos != pgd_list.next);
break;
}
spin_unlock_irqrestore(&pgd_lock, flags);
if (pos != pgd_list.next)
set_bit(pgd_index(address), insync);
}
if (address == start && test_bit(pgd_index(address), insync))
start = address + PGDIR_SIZE;
}
#endif
}