linux-yocto - Yocto Linux Embedded kernel

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Commits per author per week (path 'lib/test_overflow.c')

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/* * arch/sparc64/mm/fault.c: Page fault handlers for the 64-bit Sparc. * * Copyright (C) 1996, 2008 David S. Miller (davem@davemloft.net) * Copyright (C) 1997, 1999 Jakub Jelinek (jj@ultra.linux.cz) */ #include <asm/head.h> #include <linux/string.h> #include <linux/types.h> #include <linux/sched.h> #include <linux/ptrace.h> #include <linux/mman.h> #include <linux/signal.h> #include <linux/mm.h> #include <linux/module.h> #include <linux/init.h> #include <linux/perf_event.h> #include <linux/interrupt.h> #include <linux/kprobes.h> #include <linux/kdebug.h> #include <linux/percpu.h> #include <linux/context_tracking.h> #include <asm/page.h> #include <asm/pgtable.h> #include <asm/openprom.h> #include <asm/oplib.h> #include <asm/uaccess.h> #include <asm/asi.h> #include <asm/lsu.h> #include <asm/sections.h> #include <asm/mmu_context.h> #include <asm/setup.h> int show_unhandled_signals = 1; static inline __kprobes int notify_page_fault(struct pt_regs *regs) { int ret = 0; /* kprobe_running() needs smp_processor_id() */ if (kprobes_built_in() && !user_mode(regs)) { preempt_disable(); if (kprobe_running() && kprobe_fault_handler(regs, 0)) ret = 1; preempt_enable(); } return ret; } static void __kprobes unhandled_fault(unsigned long address, struct task_struct *tsk, struct pt_regs *regs) { if ((unsigned long) address < PAGE_SIZE) { printk(KERN_ALERT "Unable to handle kernel NULL " "pointer dereference\n"); } else { printk(KERN_ALERT "Unable to handle kernel paging request " "at virtual address %016lx\n", (unsigned long)address); } printk(KERN_ALERT "tsk->{mm,active_mm}->context = %016lx\n", (tsk->mm ? CTX_HWBITS(tsk->mm->context) : CTX_HWBITS(tsk->active_mm->context))); printk(KERN_ALERT "tsk->{mm,active_mm}->pgd = %016lx\n", (tsk->mm ? (unsigned long) tsk->mm->pgd : (unsigned long) tsk->active_mm->pgd)); die_if_kernel("Oops", regs); } static void __kprobes bad_kernel_pc(struct pt_regs *regs, unsigned long vaddr) { printk(KERN_CRIT "OOPS: Bogus kernel PC [%016lx] in fault handler\n", regs->tpc); printk(KERN_CRIT "OOPS: RPC [%016lx]\n", regs->u_regs[15]); printk("OOPS: RPC <%pS>\n", (void *) regs->u_regs[15]); printk(KERN_CRIT "OOPS: Fault was to vaddr[%lx]\n", vaddr); dump_stack(); unhandled_fault(regs->tpc, current, regs); } /* * We now make sure that mmap_sem is held in all paths that call * this. Additionally, to prevent kswapd from ripping ptes from * under us, raise interrupts around the time that we look at the * pte, kswapd will have to wait to get his smp ipi response from * us. vmtruncate likewise. This saves us having to get pte lock. */ static unsigned int get_user_insn(unsigned long tpc) { pgd_t *pgdp = pgd_offset(current->mm, tpc); pud_t *pudp; pmd_t *pmdp; pte_t *ptep, pte; unsigned long pa; u32 insn = 0; if (pgd_none(*pgdp) || unlikely(pgd_bad(*pgdp))) goto out; pudp = pud_offset(pgdp, tpc); if (pud_none(*pudp) || unlikely(pud_bad(*pudp))) goto out; /* This disables preemption for us as well. */ local_irq_disable(); pmdp = pmd_offset(pudp, tpc); if (pmd_none(*pmdp) || unlikely(pmd_bad(*pmdp))) goto out_irq_enable; #ifdef CONFIG_TRANSPARENT_HUGEPAGE if (pmd_trans_huge(*pmdp)) { if (pmd_trans_splitting(*pmdp)) goto out_irq_enable; pa = pmd_pfn(*pmdp) << PAGE_SHIFT; pa += tpc & ~HPAGE_MASK; /* Use phys bypass so we don't pollute dtlb/dcache. */ __asm__ __volatile__("lduwa [%1] %2, %0" : "=r" (insn) : "r" (pa), "i" (ASI_PHYS_USE_EC)); } else #endif { ptep = pte_offset_map(pmdp, tpc); pte = *ptep; if (pte_present(pte)) { pa = (pte_pfn(pte) << PAGE_SHIFT); pa += (tpc & ~PAGE_MASK); /* Use phys bypass so we don't pollute dtlb/dcache. */ __asm__ __volatile__("lduwa [%1] %2, %0" : "=r" (insn) : "r" (pa), "i" (ASI_PHYS_USE_EC)); } pte_unmap(ptep); } out_irq_enable: local_irq_enable(); out: return insn; } static inline void show_signal_msg(struct pt_regs *regs, int sig, int code, unsigned long address, struct task_struct *tsk) { if (!unhandled_signal(tsk, sig)) return; if (!printk_ratelimit()) return; printk("%s%s[%d]: segfault at %lx ip %p (rpc %p) sp %p error %x", task_pid_nr(tsk) > 1 ? KERN_INFO : KERN_EMERG, tsk->comm, task_pid_nr(tsk), address, (void *)regs->tpc, (void *)regs->u_regs[UREG_I7], (void *)regs->u_regs[UREG_FP], code); print_vma_addr(KERN_CONT " in ", regs->tpc); printk(KERN_CONT "\n"); } static void do_fault_siginfo(int code, int sig, struct pt_regs *regs, unsigned long fault_addr, unsigned int insn, int fault_code) { unsigned long addr; siginfo_t info; info.si_code = code; info.si_signo = sig; info.si_errno = 0; if (fault_code & FAULT_CODE_ITLB) { addr = regs->tpc; } else { /* If we were able to probe the faulting instruction, use it * to compute a precise fault address. Otherwise use the fault * time provided address which may only have page granularity. */ if (insn) addr = compute_effective_address(regs, insn, 0); else addr = fault_addr; } info.si_addr = (void __user *) addr; info.si_trapno = 0; if (unlikely(show_unhandled_signals)) show_signal_msg(regs, sig, code, addr, current); force_sig_info(sig, &info, current); } static unsigned int get_fault_insn(struct pt_regs *regs, unsigned int insn) { if (!insn) { if (!regs->tpc || (regs->tpc & 0x3)) return 0; if (regs->tstate & TSTATE_PRIV) { insn = *(unsigned int *) regs->tpc; } else { insn = get_user_insn(regs->tpc); } } return insn; } static void __kprobes do_kernel_fault(struct pt_regs *regs, int si_code, int fault_code, unsigned int insn, unsigned long address) { unsigned char asi = ASI_P; if ((!insn) && (regs->tstate & TSTATE_PRIV)) goto cannot_handle; /* If user insn could be read (thus insn is zero), that * is fine. We will just gun down the process with a signal * in that case. */ if (!(fault_code & (FAULT_CODE_WRITE|FAULT_CODE_ITLB)) && (insn & 0xc0800000) == 0xc0800000) { if (insn & 0x2000) asi = (regs->tstate >> 24); else asi = (insn >> 5); if ((asi & 0xf2) == 0x82) { if (insn & 0x1000000) { handle_ldf_stq(insn, regs); } else { /* This was a non-faulting load. Just clear the * destination register(s) and continue with the next * instruction. -jj */ handle_ld_nf(insn, regs); } return; } } /* Is this in ex_table? */ if (regs->tstate & TSTATE_PRIV) { const struct exception_table_entry *entry; entry = search_exception_tables(regs->tpc); if (entry) { regs->tpc = entry->fixup; regs->tnpc = regs->tpc + 4; return; } } else { /* The si_code was set to make clear whether * this was a SEGV_MAPERR or SEGV_ACCERR fault. */ do_fault_siginfo(si_code, SIGSEGV, regs, address, insn, fault_code); return; } cannot_handle: unhandled_fault (address, current, regs); } static void noinline __kprobes bogus_32bit_fault_tpc(struct pt_regs *regs) { static int times; if (times++ < 10) printk(KERN_ERR "FAULT[%s:%d]: 32-bit process reports " "64-bit TPC [%lx]\n", current->comm, current->pid, regs->tpc); show_regs(regs); } asmlinkage void __kprobes do_sparc64_fault(struct pt_regs *regs) { enum ctx_state prev_state = exception_enter(); struct mm_struct *mm = current->mm; struct vm_area_struct *vma; unsigned int insn = 0; int si_code, fault_code, fault; unsigned long address, mm_rss; unsigned int flags = FAULT_FLAG_ALLOW_RETRY | FAULT_FLAG_KILLABLE; fault_code = get_thread_fault_code(); if (notify_page_fault(regs)) goto exit_exception; si_code = SEGV_MAPERR; address = current_thread_info()->fault_address; if ((fault_code & FAULT_CODE_ITLB) && (fault_code & FAULT_CODE_DTLB)) BUG(); if (test_thread_flag(TIF_32BIT)) { if (!(regs->tstate & TSTATE_PRIV)) { if (unlikely((regs->tpc >> 32) != 0)) { bogus_32bit_fault_tpc(regs); goto intr_or_no_mm; } } if (unlikely((address >> 32) != 0)) goto intr_or_no_mm; } if (regs->tstate & TSTATE_PRIV) { unsigned long tpc = regs->tpc; /* Sanity check the PC. */ if ((tpc >= KERNBASE && tpc < (unsigned long) __init_end) || (tpc >= MODULES_VADDR && tpc < MODULES_END)) { /* Valid, no problems... */ } else { bad_kernel_pc(regs, address); goto exit_exception; } } else flags |= FAULT_FLAG_USER; /* * If we're in an interrupt or have no user * context, we must not take the fault.. */ if (in_atomic() || !mm) goto intr_or_no_mm; perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS, 1, regs, address); if (!down_read_trylock(&mm->mmap_sem)) { if ((regs->tstate & TSTATE_PRIV) && !search_exception_tables(regs->tpc)) { insn = get_fault_insn(regs, insn); goto handle_kernel_fault; } retry: down_read(&mm->mmap_sem); } if (fault_code & FAULT_CODE_BAD_RA) goto do_sigbus; vma = find_vma(mm, address); if (!vma) goto bad_area; /* Pure DTLB misses do not tell us whether the fault causing * load/store/atomic was a write or not, it only says that there * was no match. So in such a case we (carefully) read the * instruction to try and figure this out. It's an optimization * so it's ok if we can't do this. * * Special hack, window spill/fill knows the exact fault type. */ if (((fault_code & (FAULT_CODE_DTLB | FAULT_CODE_WRITE | FAULT_CODE_WINFIXUP)) == FAULT_CODE_DTLB) && (vma->vm_flags & VM_WRITE) != 0) { insn = get_fault_insn(regs, 0); if (!insn) goto continue_fault; /* All loads, stores and atomics have bits 30 and 31 both set * in the instruction. Bit 21 is set in all stores, but we * have to avoid prefetches which also have bit 21 set. */ if ((insn & 0xc0200000) == 0xc0200000 && (insn & 0x01780000) != 0x01680000) { /* Don't bother updating thread struct value, * because update_mmu_cache only cares which tlb * the access came from. */ fault_code |= FAULT_CODE_WRITE; } } continue_fault: if (vma->vm_start <= address) goto good_area; if (!(vma->vm_flags & VM_GROWSDOWN)) goto bad_area; if (!(fault_code & FAULT_CODE_WRITE)) { /* Non-faulting loads shouldn't expand stack. */ insn = get_fault_insn(regs, insn); if ((insn & 0xc0800000) == 0xc0800000) { unsigned char asi; if (insn & 0x2000) asi = (regs->tstate >> 24); else asi = (insn >> 5); if ((asi & 0xf2) == 0x82) 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 we took a ITLB miss on a non-executable page, catch * that here. */ if ((fault_code & FAULT_CODE_ITLB) && !(vma->vm_flags & VM_EXEC)) { BUG_ON(address != regs->tpc); BUG_ON(regs->tstate & TSTATE_PRIV); goto bad_area; } if (fault_code & FAULT_CODE_WRITE) { if (!(vma->vm_flags & VM_WRITE)) goto bad_area; /* Spitfire has an icache which does not snoop * processor stores. Later processors do... */ if (tlb_type == spitfire && (vma->vm_flags & VM_EXEC) != 0 && vma->vm_file != NULL) set_thread_fault_code(fault_code | FAULT_CODE_BLKCOMMIT); flags |= FAULT_FLAG_WRITE; } else { /* Allow reads even for write-only mappings */ if (!(vma->vm_flags & (VM_READ | VM_EXEC))) goto bad_area; } fault = handle_mm_fault(mm, vma, address, flags); if ((fault & VM_FAULT_RETRY) && fatal_signal_pending(current)) goto exit_exception; 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) { current->maj_flt++; perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS_MAJ, 1, regs, address); } else { current->min_flt++; perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS_MIN, 1, regs, address); } 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); mm_rss = get_mm_rss(mm); #if defined(CONFIG_HUGETLB_PAGE) || defined(CONFIG_TRANSPARENT_HUGEPAGE) mm_rss -= (mm->context.huge_pte_count * (HPAGE_SIZE / PAGE_SIZE)); #endif if (unlikely(mm_rss > mm->context.tsb_block[MM_TSB_BASE].tsb_rss_limit)) tsb_grow(mm, MM_TSB_BASE, mm_rss); #if defined(CONFIG_HUGETLB_PAGE) || defined(CONFIG_TRANSPARENT_HUGEPAGE) mm_rss = mm->context.huge_pte_count; if (unlikely(mm_rss > mm->context.tsb_block[MM_TSB_HUGE].tsb_rss_limit)) { if (mm->context.tsb_block[MM_TSB_HUGE].tsb) tsb_grow(mm, MM_TSB_HUGE, mm_rss); else hugetlb_setup(regs); } #endif exit_exception: exception_exit(prev_state); return; /* * 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: insn = get_fault_insn(regs, insn); up_read(&mm->mmap_sem); handle_kernel_fault: do_kernel_fault(regs, si_code, fault_code, insn, address); goto exit_exception; /* * 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: insn = get_fault_insn(regs, insn); up_read(&mm->mmap_sem); if (!(regs->tstate & TSTATE_PRIV)) { pagefault_out_of_memory(); goto exit_exception; } goto handle_kernel_fault; intr_or_no_mm: insn = get_fault_insn(regs, 0); goto handle_kernel_fault; do_sigbus: insn = get_fault_insn(regs, insn); up_read(&mm->mmap_sem); /* * Send a sigbus, regardless of whether we were in kernel * or user mode. */ do_fault_siginfo(BUS_ADRERR, SIGBUS, regs, address, insn, fault_code); /* Kernel mode? Handle exceptions or die */ if (regs->tstate & TSTATE_PRIV) goto handle_kernel_fault; }


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