diff options
Diffstat (limited to 'ANDROID_3.4.5/arch/powerpc/mm/fault.c')
-rw-r--r-- | ANDROID_3.4.5/arch/powerpc/mm/fault.c | 521 |
1 files changed, 0 insertions, 521 deletions
diff --git a/ANDROID_3.4.5/arch/powerpc/mm/fault.c b/ANDROID_3.4.5/arch/powerpc/mm/fault.c deleted file mode 100644 index 08ffcf52..00000000 --- a/ANDROID_3.4.5/arch/powerpc/mm/fault.c +++ /dev/null @@ -1,521 +0,0 @@ -/* - * PowerPC version - * Copyright (C) 1995-1996 Gary Thomas (gdt@linuxppc.org) - * - * Derived from "arch/i386/mm/fault.c" - * Copyright (C) 1991, 1992, 1993, 1994 Linus Torvalds - * - * Modified by Cort Dougan and Paul Mackerras. - * - * Modified for PPC64 by Dave Engebretsen (engebret@ibm.com) - * - * 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; either version - * 2 of the License, or (at your option) any later version. - */ - -#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/interrupt.h> -#include <linux/highmem.h> -#include <linux/module.h> -#include <linux/kprobes.h> -#include <linux/kdebug.h> -#include <linux/perf_event.h> -#include <linux/magic.h> -#include <linux/ratelimit.h> - -#include <asm/firmware.h> -#include <asm/page.h> -#include <asm/pgtable.h> -#include <asm/mmu.h> -#include <asm/mmu_context.h> -#include <asm/uaccess.h> -#include <asm/tlbflush.h> -#include <asm/siginfo.h> -#include <asm/debug.h> -#include <mm/mmu_decl.h> - -#include "icswx.h" - -#ifdef CONFIG_KPROBES -static inline int notify_page_fault(struct pt_regs *regs) -{ - int ret = 0; - - /* kprobe_running() needs smp_processor_id() */ - if (!user_mode(regs)) { - preempt_disable(); - if (kprobe_running() && kprobe_fault_handler(regs, 11)) - ret = 1; - preempt_enable(); - } - - return ret; -} -#else -static inline int notify_page_fault(struct pt_regs *regs) -{ - return 0; -} -#endif - -/* - * Check whether the instruction at regs->nip is a store using - * an update addressing form which will update r1. - */ -static int store_updates_sp(struct pt_regs *regs) -{ - unsigned int inst; - - if (get_user(inst, (unsigned int __user *)regs->nip)) - return 0; - /* check for 1 in the rA field */ - if (((inst >> 16) & 0x1f) != 1) - return 0; - /* check major opcode */ - switch (inst >> 26) { - case 37: /* stwu */ - case 39: /* stbu */ - case 45: /* sthu */ - case 53: /* stfsu */ - case 55: /* stfdu */ - return 1; - case 62: /* std or stdu */ - return (inst & 3) == 1; - case 31: - /* check minor opcode */ - switch ((inst >> 1) & 0x3ff) { - case 181: /* stdux */ - case 183: /* stwux */ - case 247: /* stbux */ - case 439: /* sthux */ - case 695: /* stfsux */ - case 759: /* stfdux */ - return 1; - } - } - return 0; -} -/* - * do_page_fault error handling helpers - */ - -#define MM_FAULT_RETURN 0 -#define MM_FAULT_CONTINUE -1 -#define MM_FAULT_ERR(sig) (sig) - -static int out_of_memory(struct pt_regs *regs) -{ - /* - * We ran out of memory, or some other thing happened to us that made - * us unable to handle the page fault gracefully. - */ - up_read(¤t->mm->mmap_sem); - if (!user_mode(regs)) - return MM_FAULT_ERR(SIGKILL); - pagefault_out_of_memory(); - return MM_FAULT_RETURN; -} - -static int do_sigbus(struct pt_regs *regs, unsigned long address) -{ - siginfo_t info; - - up_read(¤t->mm->mmap_sem); - - if (user_mode(regs)) { - info.si_signo = SIGBUS; - info.si_errno = 0; - info.si_code = BUS_ADRERR; - info.si_addr = (void __user *)address; - force_sig_info(SIGBUS, &info, current); - return MM_FAULT_RETURN; - } - return MM_FAULT_ERR(SIGBUS); -} - -static int mm_fault_error(struct pt_regs *regs, unsigned long addr, int fault) -{ - /* - * Pagefault was interrupted by SIGKILL. We have no reason to - * continue the pagefault. - */ - if (fatal_signal_pending(current)) { - /* - * If we have retry set, the mmap semaphore will have - * alrady been released in __lock_page_or_retry(). Else - * we release it now. - */ - if (!(fault & VM_FAULT_RETRY)) - up_read(¤t->mm->mmap_sem); - /* Coming from kernel, we need to deal with uaccess fixups */ - if (user_mode(regs)) - return MM_FAULT_RETURN; - return MM_FAULT_ERR(SIGKILL); - } - - /* No fault: be happy */ - if (!(fault & VM_FAULT_ERROR)) - return MM_FAULT_CONTINUE; - - /* Out of memory */ - if (fault & VM_FAULT_OOM) - return out_of_memory(regs); - - /* Bus error. x86 handles HWPOISON here, we'll add this if/when - * we support the feature in HW - */ - if (fault & VM_FAULT_SIGBUS) - return do_sigbus(regs, addr); - - /* We don't understand the fault code, this is fatal */ - BUG(); - return MM_FAULT_CONTINUE; -} - -/* - * For 600- and 800-family processors, the error_code parameter is DSISR - * for a data fault, SRR1 for an instruction fault. For 400-family processors - * the error_code parameter is ESR for a data fault, 0 for an instruction - * fault. - * For 64-bit processors, the error_code parameter is - * - DSISR for a non-SLB data access fault, - * - SRR1 & 0x08000000 for a non-SLB instruction access fault - * - 0 any SLB fault. - * - * The return value is 0 if the fault was handled, or the signal - * number if this is a kernel fault that can't be handled here. - */ -int __kprobes do_page_fault(struct pt_regs *regs, unsigned long address, - unsigned long error_code) -{ - struct vm_area_struct * vma; - struct mm_struct *mm = current->mm; - unsigned int flags = FAULT_FLAG_ALLOW_RETRY | FAULT_FLAG_KILLABLE; - int code = SEGV_MAPERR; - int is_write = 0; - int trap = TRAP(regs); - int is_exec = trap == 0x400; - int fault; - -#if !(defined(CONFIG_4xx) || defined(CONFIG_BOOKE)) - /* - * Fortunately the bit assignments in SRR1 for an instruction - * fault and DSISR for a data fault are mostly the same for the - * bits we are interested in. But there are some bits which - * indicate errors in DSISR but can validly be set in SRR1. - */ - if (trap == 0x400) - error_code &= 0x48200000; - else - is_write = error_code & DSISR_ISSTORE; -#else - is_write = error_code & ESR_DST; -#endif /* CONFIG_4xx || CONFIG_BOOKE */ - - if (is_write) - flags |= FAULT_FLAG_WRITE; - -#ifdef CONFIG_PPC_ICSWX - /* - * we need to do this early because this "data storage - * interrupt" does not update the DAR/DEAR so we don't want to - * look at it - */ - if (error_code & ICSWX_DSI_UCT) { - int rc = acop_handle_fault(regs, address, error_code); - if (rc) - return rc; - } -#endif /* CONFIG_PPC_ICSWX */ - - if (notify_page_fault(regs)) - return 0; - - if (unlikely(debugger_fault_handler(regs))) - return 0; - - /* On a kernel SLB miss we can only check for a valid exception entry */ - if (!user_mode(regs) && (address >= TASK_SIZE)) - return SIGSEGV; - -#if !(defined(CONFIG_4xx) || defined(CONFIG_BOOKE) || \ - defined(CONFIG_PPC_BOOK3S_64)) - if (error_code & DSISR_DABRMATCH) { - /* DABR match */ - do_dabr(regs, address, error_code); - return 0; - } -#endif - - /* We restore the interrupt state now */ - if (!arch_irq_disabled_regs(regs)) - local_irq_enable(); - - if (in_atomic() || mm == NULL) { - if (!user_mode(regs)) - return SIGSEGV; - /* in_atomic() in user mode is really bad, - as is current->mm == NULL. */ - printk(KERN_EMERG "Page fault in user mode with " - "in_atomic() = %d mm = %p\n", in_atomic(), mm); - printk(KERN_EMERG "NIP = %lx MSR = %lx\n", - regs->nip, regs->msr); - die("Weird page fault", regs, SIGSEGV); - } - - perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS, 1, regs, address); - - /* 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 (!user_mode(regs) && !search_exception_tables(regs->nip)) - goto bad_area_nosemaphore; - -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(); - } - - 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; - - /* - * N.B. The POWER/Open ABI allows programs to access up to - * 288 bytes below the stack pointer. - * The kernel signal delivery code writes up to about 1.5kB - * below the stack pointer (r1) before decrementing it. - * The exec code can write slightly over 640kB to the stack - * before setting the user r1. Thus we allow the stack to - * expand to 1MB without further checks. - */ - if (address + 0x100000 < vma->vm_end) { - /* get user regs even if this fault is in kernel mode */ - struct pt_regs *uregs = current->thread.regs; - if (uregs == NULL) - goto bad_area; - - /* - * A user-mode access to an address a long way below - * the stack pointer is only valid if the instruction - * is one which would update the stack pointer to the - * address accessed if the instruction completed, - * i.e. either stwu rs,n(r1) or stwux rs,r1,rb - * (or the byte, halfword, float or double forms). - * - * If we don't check this then any write to the area - * between the last mapped region and the stack will - * expand the stack rather than segfaulting. - */ - if (address + 2048 < uregs->gpr[1] - && (!user_mode(regs) || !store_updates_sp(regs))) - goto bad_area; - } - if (expand_stack(vma, address)) - goto bad_area; - -good_area: - code = SEGV_ACCERR; -#if defined(CONFIG_6xx) - if (error_code & 0x95700000) - /* an error such as lwarx to I/O controller space, - address matching DABR, eciwx, etc. */ - goto bad_area; -#endif /* CONFIG_6xx */ -#if defined(CONFIG_8xx) - /* 8xx sometimes need to load a invalid/non-present TLBs. - * These must be invalidated separately as linux mm don't. - */ - if (error_code & 0x40000000) /* no translation? */ - _tlbil_va(address, 0, 0, 0); - - /* The MPC8xx seems to always set 0x80000000, which is - * "undefined". Of those that can be set, this is the only - * one which seems bad. - */ - if (error_code & 0x10000000) - /* Guarded storage error. */ - goto bad_area; -#endif /* CONFIG_8xx */ - - if (is_exec) { -#ifdef CONFIG_PPC_STD_MMU - /* Protection fault on exec go straight to failure on - * Hash based MMUs as they either don't support per-page - * execute permission, or if they do, it's handled already - * at the hash level. This test would probably have to - * be removed if we change the way this works to make hash - * processors use the same I/D cache coherency mechanism - * as embedded. - */ - if (error_code & DSISR_PROTFAULT) - goto bad_area; -#endif /* CONFIG_PPC_STD_MMU */ - - /* - * Allow execution from readable areas if the MMU does not - * provide separate controls over reading and executing. - * - * Note: That code used to not be enabled for 4xx/BookE. - * It is now as I/D cache coherency for these is done at - * set_pte_at() time and I see no reason why the test - * below wouldn't be valid on those processors. This -may- - * break programs compiled with a really old ABI though. - */ - if (!(vma->vm_flags & VM_EXEC) && - (cpu_has_feature(CPU_FTR_NOEXECUTE) || - !(vma->vm_flags & (VM_READ | VM_WRITE)))) - goto bad_area; - /* a write */ - } else if (is_write) { - if (!(vma->vm_flags & VM_WRITE)) - goto bad_area; - /* a read */ - } else { - /* protection fault */ - if (error_code & 0x08000000) - goto bad_area; - if (!(vma->vm_flags & (VM_READ | VM_EXEC | VM_WRITE))) - 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 (unlikely(fault & (VM_FAULT_RETRY|VM_FAULT_ERROR))) { - int rc = mm_fault_error(regs, address, fault); - if (rc >= MM_FAULT_RETURN) - return rc; - } - - /* - * Major/minor page fault accounting is only done on the - * initial attempt. If we go through a retry, it is extremely - * likely that the page will be found in page cache at that point. - */ - 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); -#ifdef CONFIG_PPC_SMLPAR - if (firmware_has_feature(FW_FEATURE_CMO)) { - preempt_disable(); - get_lppaca()->page_ins += (1 << PAGE_FACTOR); - preempt_enable(); - } -#endif /* CONFIG_PPC_SMLPAR */ - } else { - current->min_flt++; - perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS_MIN, 1, - regs, address); - } - 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); - return 0; - -bad_area: - up_read(&mm->mmap_sem); - -bad_area_nosemaphore: - /* User mode accesses cause a SIGSEGV */ - if (user_mode(regs)) { - _exception(SIGSEGV, regs, code, address); - return 0; - } - - if (is_exec && (error_code & DSISR_PROTFAULT)) - printk_ratelimited(KERN_CRIT "kernel tried to execute NX-protected" - " page (%lx) - exploit attempt? (uid: %d)\n", - address, current_uid()); - - return SIGSEGV; - -} - -/* - * bad_page_fault is called when we have a bad access from the kernel. - * It is called from the DSI and ISI handlers in head.S and from some - * of the procedures in traps.c. - */ -void bad_page_fault(struct pt_regs *regs, unsigned long address, int sig) -{ - const struct exception_table_entry *entry; - unsigned long *stackend; - - /* Are we prepared to handle this fault? */ - if ((entry = search_exception_tables(regs->nip)) != NULL) { - regs->nip = entry->fixup; - return; - } - - /* kernel has accessed a bad area */ - - switch (regs->trap) { - case 0x300: - case 0x380: - printk(KERN_ALERT "Unable to handle kernel paging request for " - "data at address 0x%08lx\n", regs->dar); - break; - case 0x400: - case 0x480: - printk(KERN_ALERT "Unable to handle kernel paging request for " - "instruction fetch\n"); - break; - default: - printk(KERN_ALERT "Unable to handle kernel paging request for " - "unknown fault\n"); - break; - } - printk(KERN_ALERT "Faulting instruction address: 0x%08lx\n", - regs->nip); - - stackend = end_of_stack(current); - if (current != &init_task && *stackend != STACK_END_MAGIC) - printk(KERN_ALERT "Thread overran stack, or stack corrupted\n"); - - die("Kernel access of bad area", regs, sig); -} |