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Diffstat (limited to 'kernel/arch/tile/mm/fault.c')
| -rw-r--r-- | kernel/arch/tile/mm/fault.c | 921 |
1 files changed, 921 insertions, 0 deletions
diff --git a/kernel/arch/tile/mm/fault.c b/kernel/arch/tile/mm/fault.c new file mode 100644 index 000000000..3f4f58d34 --- /dev/null +++ b/kernel/arch/tile/mm/fault.c @@ -0,0 +1,921 @@ +/* + * 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 <linux/context_tracking.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 + * region with pagefaults disabled then we must not take the fault. + */ + if (pagefault_disabled() || !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_SIGSEGV) + goto bad_area; + 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", + 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; + enum ctx_state prev_state = exception_enter(); + +#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) + goto done; +#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); + } + } +#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; + goto done; + } + } +#endif + + handle_page_fault(regs, fault_num, is_page_fault, address, write); + +done: + exception_exit(prev_state); +} + + +#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 +} |