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Diffstat (limited to 'cleopatre/linux-2.6.25.10-spc300/arch/s390/mm/fault.c')
-rw-r--r--cleopatre/linux-2.6.25.10-spc300/arch/s390/mm/fault.c618
1 files changed, 618 insertions, 0 deletions
diff --git a/cleopatre/linux-2.6.25.10-spc300/arch/s390/mm/fault.c b/cleopatre/linux-2.6.25.10-spc300/arch/s390/mm/fault.c
new file mode 100644
index 0000000000..ed13d429a4
--- /dev/null
+++ b/cleopatre/linux-2.6.25.10-spc300/arch/s390/mm/fault.c
@@ -0,0 +1,618 @@
+/*
+ * arch/s390/mm/fault.c
+ *
+ * S390 version
+ * Copyright (C) 1999 IBM Deutschland Entwicklung GmbH, IBM Corporation
+ * Author(s): Hartmut Penner (hp@de.ibm.com)
+ * Ulrich Weigand (uweigand@de.ibm.com)
+ *
+ * Derived from "arch/i386/mm/fault.c"
+ * 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/kdebug.h>
+#include <linux/smp_lock.h>
+#include <linux/init.h>
+#include <linux/console.h>
+#include <linux/module.h>
+#include <linux/hardirq.h>
+#include <linux/kprobes.h>
+#include <linux/uaccess.h>
+
+#include <asm/system.h>
+#include <asm/pgtable.h>
+#include <asm/s390_ext.h>
+#include <asm/mmu_context.h>
+
+#ifndef CONFIG_64BIT
+#define __FAIL_ADDR_MASK 0x7ffff000
+#define __FIXUP_MASK 0x7fffffff
+#define __SUBCODE_MASK 0x0200
+#define __PF_RES_FIELD 0ULL
+#else /* CONFIG_64BIT */
+#define __FAIL_ADDR_MASK -4096L
+#define __FIXUP_MASK ~0L
+#define __SUBCODE_MASK 0x0600
+#define __PF_RES_FIELD 0x8000000000000000ULL
+#endif /* CONFIG_64BIT */
+
+#ifdef CONFIG_SYSCTL
+extern int sysctl_userprocess_debug;
+#endif
+
+extern void die(const char *,struct pt_regs *,long);
+
+#ifdef CONFIG_KPROBES
+static inline int notify_page_fault(struct pt_regs *regs, long err)
+{
+ int ret = 0;
+
+ /* kprobe_running() needs smp_processor_id() */
+ if (!user_mode(regs)) {
+ preempt_disable();
+ if (kprobe_running() && kprobe_fault_handler(regs, 14))
+ ret = 1;
+ preempt_enable();
+ }
+
+ return ret;
+}
+#else
+static inline int notify_page_fault(struct pt_regs *regs, long err)
+{
+ return 0;
+}
+#endif
+
+
+/*
+ * Unlock any spinlocks which will prevent us from getting the
+ * message out.
+ */
+void bust_spinlocks(int yes)
+{
+ if (yes) {
+ oops_in_progress = 1;
+ } else {
+ int loglevel_save = console_loglevel;
+ console_unblank();
+ oops_in_progress = 0;
+ /*
+ * OK, the message is on the console. Now we call printk()
+ * without oops_in_progress set so that printk will give klogd
+ * a poke. Hold onto your hats...
+ */
+ console_loglevel = 15;
+ printk(" ");
+ console_loglevel = loglevel_save;
+ }
+}
+
+/*
+ * Returns the address space associated with the fault.
+ * Returns 0 for kernel space, 1 for user space and
+ * 2 for code execution in user space with noexec=on.
+ */
+static inline int check_space(struct task_struct *tsk)
+{
+ /*
+ * The lowest two bits of S390_lowcore.trans_exc_code
+ * indicate which paging table was used.
+ */
+ int desc = S390_lowcore.trans_exc_code & 3;
+
+ if (desc == 3) /* Home Segment Table Descriptor */
+ return switch_amode == 0;
+ if (desc == 2) /* Secondary Segment Table Descriptor */
+ return tsk->thread.mm_segment.ar4;
+#ifdef CONFIG_S390_SWITCH_AMODE
+ if (unlikely(desc == 1)) { /* STD determined via access register */
+ /* %a0 always indicates primary space. */
+ if (S390_lowcore.exc_access_id != 0) {
+ save_access_regs(tsk->thread.acrs);
+ /*
+ * An alet of 0 indicates primary space.
+ * An alet of 1 indicates secondary space.
+ * Any other alet values generate an
+ * alen-translation exception.
+ */
+ if (tsk->thread.acrs[S390_lowcore.exc_access_id])
+ return tsk->thread.mm_segment.ar4;
+ }
+ }
+#endif
+ /* Primary Segment Table Descriptor */
+ return switch_amode << s390_noexec;
+}
+
+/*
+ * Send SIGSEGV to task. This is an external routine
+ * to keep the stack usage of do_page_fault small.
+ */
+static void do_sigsegv(struct pt_regs *regs, unsigned long error_code,
+ int si_code, unsigned long address)
+{
+ struct siginfo si;
+
+#if defined(CONFIG_SYSCTL) || defined(CONFIG_PROCESS_DEBUG)
+#if defined(CONFIG_SYSCTL)
+ if (sysctl_userprocess_debug)
+#endif
+ {
+ printk("User process fault: interruption code 0x%lX\n",
+ error_code);
+ printk("failing address: %lX\n", address);
+ show_regs(regs);
+ }
+#endif
+ si.si_signo = SIGSEGV;
+ si.si_code = si_code;
+ si.si_addr = (void __user *) address;
+ force_sig_info(SIGSEGV, &si, current);
+}
+
+static void do_no_context(struct pt_regs *regs, unsigned long error_code,
+ unsigned long address)
+{
+ const struct exception_table_entry *fixup;
+
+ /* Are we prepared to handle this kernel fault? */
+ fixup = search_exception_tables(regs->psw.addr & __FIXUP_MASK);
+ if (fixup) {
+ regs->psw.addr = fixup->fixup | PSW_ADDR_AMODE;
+ return;
+ }
+
+ /*
+ * Oops. The kernel tried to access some bad page. We'll have to
+ * terminate things with extreme prejudice.
+ */
+ if (check_space(current) == 0)
+ printk(KERN_ALERT "Unable to handle kernel pointer dereference"
+ " at virtual kernel address %p\n", (void *)address);
+ else
+ printk(KERN_ALERT "Unable to handle kernel paging request"
+ " at virtual user address %p\n", (void *)address);
+
+ die("Oops", regs, error_code);
+ do_exit(SIGKILL);
+}
+
+static void do_low_address(struct pt_regs *regs, unsigned long error_code)
+{
+ /* Low-address protection hit in kernel mode means
+ NULL pointer write access in kernel mode. */
+ if (regs->psw.mask & PSW_MASK_PSTATE) {
+ /* Low-address protection hit in user mode 'cannot happen'. */
+ die ("Low-address protection", regs, error_code);
+ do_exit(SIGKILL);
+ }
+
+ do_no_context(regs, error_code, 0);
+}
+
+/*
+ * We ran out of memory, or some other thing happened to us that made
+ * us unable to handle the page fault gracefully.
+ */
+static int do_out_of_memory(struct pt_regs *regs, unsigned long error_code,
+ unsigned long address)
+{
+ struct task_struct *tsk = current;
+ struct mm_struct *mm = tsk->mm;
+
+ up_read(&mm->mmap_sem);
+ if (is_global_init(tsk)) {
+ yield();
+ down_read(&mm->mmap_sem);
+ return 1;
+ }
+ printk("VM: killing process %s\n", tsk->comm);
+ if (regs->psw.mask & PSW_MASK_PSTATE)
+ do_group_exit(SIGKILL);
+ do_no_context(regs, error_code, address);
+ return 0;
+}
+
+static void do_sigbus(struct pt_regs *regs, unsigned long error_code,
+ unsigned long address)
+{
+ struct task_struct *tsk = current;
+ struct mm_struct *mm = tsk->mm;
+
+ up_read(&mm->mmap_sem);
+ /*
+ * Send a sigbus, regardless of whether we were in kernel
+ * or user mode.
+ */
+ tsk->thread.prot_addr = address;
+ tsk->thread.trap_no = error_code;
+ force_sig(SIGBUS, tsk);
+
+ /* Kernel mode? Handle exceptions or die */
+ if (!(regs->psw.mask & PSW_MASK_PSTATE))
+ do_no_context(regs, error_code, address);
+}
+
+#ifdef CONFIG_S390_EXEC_PROTECT
+extern long sys_sigreturn(struct pt_regs *regs);
+extern long sys_rt_sigreturn(struct pt_regs *regs);
+extern long sys32_sigreturn(struct pt_regs *regs);
+extern long sys32_rt_sigreturn(struct pt_regs *regs);
+
+static int signal_return(struct mm_struct *mm, struct pt_regs *regs,
+ unsigned long address, unsigned long error_code)
+{
+ u16 instruction;
+ int rc;
+#ifdef CONFIG_COMPAT
+ int compat;
+#endif
+
+ pagefault_disable();
+ rc = __get_user(instruction, (u16 __user *) regs->psw.addr);
+ pagefault_enable();
+ if (rc)
+ return -EFAULT;
+
+ up_read(&mm->mmap_sem);
+ clear_tsk_thread_flag(current, TIF_SINGLE_STEP);
+#ifdef CONFIG_COMPAT
+ compat = test_tsk_thread_flag(current, TIF_31BIT);
+ if (compat && instruction == 0x0a77)
+ sys32_sigreturn(regs);
+ else if (compat && instruction == 0x0aad)
+ sys32_rt_sigreturn(regs);
+ else
+#endif
+ if (instruction == 0x0a77)
+ sys_sigreturn(regs);
+ else if (instruction == 0x0aad)
+ sys_rt_sigreturn(regs);
+ else {
+ current->thread.prot_addr = address;
+ current->thread.trap_no = error_code;
+ do_sigsegv(regs, error_code, SEGV_MAPERR, address);
+ }
+ return 0;
+}
+#endif /* CONFIG_S390_EXEC_PROTECT */
+
+/*
+ * This routine handles page faults. It determines the address,
+ * and the problem, and then passes it off to one of the appropriate
+ * routines.
+ *
+ * error_code:
+ * 04 Protection -> Write-Protection (suprression)
+ * 10 Segment translation -> Not present (nullification)
+ * 11 Page translation -> Not present (nullification)
+ * 3b Region third trans. -> Not present (nullification)
+ */
+static inline void
+do_exception(struct pt_regs *regs, unsigned long error_code, int write)
+{
+ struct task_struct *tsk;
+ struct mm_struct *mm;
+ struct vm_area_struct *vma;
+ unsigned long address;
+ int space;
+ int si_code;
+ int fault;
+
+ if (notify_page_fault(regs, error_code))
+ return;
+
+ tsk = current;
+ mm = tsk->mm;
+
+ /* get the failing address and the affected space */
+ address = S390_lowcore.trans_exc_code & __FAIL_ADDR_MASK;
+ space = check_space(tsk);
+
+ /*
+ * Verify that the fault happened in user space, that
+ * we are not in an interrupt and that there is a
+ * user context.
+ */
+ if (unlikely(space == 0 || in_atomic() || !mm))
+ goto no_context;
+
+ /*
+ * When we get here, the fault happened in the current
+ * task's user address space, so we can switch on the
+ * interrupts again and then search the VMAs
+ */
+ local_irq_enable();
+
+ down_read(&mm->mmap_sem);
+
+ si_code = SEGV_MAPERR;
+ vma = find_vma(mm, address);
+ if (!vma)
+ goto bad_area;
+
+#ifdef CONFIG_S390_EXEC_PROTECT
+ if (unlikely((space == 2) && !(vma->vm_flags & VM_EXEC)))
+ if (!signal_return(mm, regs, address, error_code))
+ /*
+ * signal_return() has done an up_read(&mm->mmap_sem)
+ * if it returns 0.
+ */
+ return;
+#endif
+
+ if (vma->vm_start <= address)
+ goto good_area;
+ if (!(vma->vm_flags & VM_GROWSDOWN))
+ 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 (!write) {
+ /* page not present, check vm flags */
+ if (!(vma->vm_flags & (VM_READ | VM_EXEC | VM_WRITE)))
+ goto bad_area;
+ } else {
+ if (!(vma->vm_flags & VM_WRITE))
+ goto bad_area;
+ }
+
+survive:
+ /*
+ * 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, write);
+ if (unlikely(fault & VM_FAULT_ERROR)) {
+ if (fault & VM_FAULT_OOM) {
+ if (do_out_of_memory(regs, error_code, address))
+ goto survive;
+ return;
+ } else if (fault & VM_FAULT_SIGBUS) {
+ do_sigbus(regs, error_code, address);
+ return;
+ }
+ BUG();
+ }
+ if (fault & VM_FAULT_MAJOR)
+ tsk->maj_flt++;
+ else
+ tsk->min_flt++;
+
+ up_read(&mm->mmap_sem);
+ /*
+ * The instruction that caused the program check will
+ * be repeated. Don't signal single step via SIGTRAP.
+ */
+ clear_tsk_thread_flag(tsk, TIF_SINGLE_STEP);
+ 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:
+ up_read(&mm->mmap_sem);
+
+ /* User mode accesses just cause a SIGSEGV */
+ if (regs->psw.mask & PSW_MASK_PSTATE) {
+ tsk->thread.prot_addr = address;
+ tsk->thread.trap_no = error_code;
+ do_sigsegv(regs, error_code, si_code, address);
+ return;
+ }
+
+no_context:
+ do_no_context(regs, error_code, address);
+}
+
+void __kprobes do_protection_exception(struct pt_regs *regs,
+ unsigned long error_code)
+{
+ /* Protection exception is supressing, decrement psw address. */
+ regs->psw.addr -= (error_code >> 16);
+ /*
+ * Check for low-address protection. This needs to be treated
+ * as a special case because the translation exception code
+ * field is not guaranteed to contain valid data in this case.
+ */
+ if (unlikely(!(S390_lowcore.trans_exc_code & 4))) {
+ do_low_address(regs, error_code);
+ return;
+ }
+ do_exception(regs, 4, 1);
+}
+
+void __kprobes do_dat_exception(struct pt_regs *regs, unsigned long error_code)
+{
+ do_exception(regs, error_code & 0xff, 0);
+}
+
+#ifdef CONFIG_64BIT
+void __kprobes do_asce_exception(struct pt_regs *regs, unsigned long error_code)
+{
+ struct mm_struct *mm;
+ struct vm_area_struct *vma;
+ unsigned long address;
+ int space;
+
+ mm = current->mm;
+ address = S390_lowcore.trans_exc_code & __FAIL_ADDR_MASK;
+ space = check_space(current);
+
+ if (unlikely(space == 0 || in_atomic() || !mm))
+ goto no_context;
+
+ local_irq_enable();
+
+ down_read(&mm->mmap_sem);
+ vma = find_vma(mm, address);
+ up_read(&mm->mmap_sem);
+
+ if (vma) {
+ update_mm(mm, current);
+ return;
+ }
+
+ /* User mode accesses just cause a SIGSEGV */
+ if (regs->psw.mask & PSW_MASK_PSTATE) {
+ current->thread.prot_addr = address;
+ current->thread.trap_no = error_code;
+ do_sigsegv(regs, error_code, SEGV_MAPERR, address);
+ return;
+ }
+
+no_context:
+ do_no_context(regs, error_code, address);
+}
+#endif
+
+#ifdef CONFIG_PFAULT
+/*
+ * 'pfault' pseudo page faults routines.
+ */
+static ext_int_info_t ext_int_pfault;
+static int pfault_disable = 0;
+
+static int __init nopfault(char *str)
+{
+ pfault_disable = 1;
+ return 1;
+}
+
+__setup("nopfault", nopfault);
+
+typedef struct {
+ __u16 refdiagc;
+ __u16 reffcode;
+ __u16 refdwlen;
+ __u16 refversn;
+ __u64 refgaddr;
+ __u64 refselmk;
+ __u64 refcmpmk;
+ __u64 reserved;
+} __attribute__ ((packed, aligned(8))) pfault_refbk_t;
+
+int pfault_init(void)
+{
+ pfault_refbk_t refbk =
+ { 0x258, 0, 5, 2, __LC_CURRENT, 1ULL << 48, 1ULL << 48,
+ __PF_RES_FIELD };
+ int rc;
+
+ if (!MACHINE_IS_VM || pfault_disable)
+ return -1;
+ asm volatile(
+ " diag %1,%0,0x258\n"
+ "0: j 2f\n"
+ "1: la %0,8\n"
+ "2:\n"
+ EX_TABLE(0b,1b)
+ : "=d" (rc) : "a" (&refbk), "m" (refbk) : "cc");
+ __ctl_set_bit(0, 9);
+ return rc;
+}
+
+void pfault_fini(void)
+{
+ pfault_refbk_t refbk =
+ { 0x258, 1, 5, 2, 0ULL, 0ULL, 0ULL, 0ULL };
+
+ if (!MACHINE_IS_VM || pfault_disable)
+ return;
+ __ctl_clear_bit(0,9);
+ asm volatile(
+ " diag %0,0,0x258\n"
+ "0:\n"
+ EX_TABLE(0b,0b)
+ : : "a" (&refbk), "m" (refbk) : "cc");
+}
+
+static void pfault_interrupt(__u16 error_code)
+{
+ struct task_struct *tsk;
+ __u16 subcode;
+
+ /*
+ * Get the external interruption subcode & pfault
+ * initial/completion signal bit. VM stores this
+ * in the 'cpu address' field associated with the
+ * external interrupt.
+ */
+ subcode = S390_lowcore.cpu_addr;
+ if ((subcode & 0xff00) != __SUBCODE_MASK)
+ return;
+
+ /*
+ * Get the token (= address of the task structure of the affected task).
+ */
+ tsk = *(struct task_struct **) __LC_PFAULT_INTPARM;
+
+ if (subcode & 0x0080) {
+ /* signal bit is set -> a page has been swapped in by VM */
+ if (xchg(&tsk->thread.pfault_wait, -1) != 0) {
+ /* Initial interrupt was faster than the completion
+ * interrupt. pfault_wait is valid. Set pfault_wait
+ * back to zero and wake up the process. This can
+ * safely be done because the task is still sleeping
+ * and can't produce new pfaults. */
+ tsk->thread.pfault_wait = 0;
+ wake_up_process(tsk);
+ put_task_struct(tsk);
+ }
+ } else {
+ /* signal bit not set -> a real page is missing. */
+ get_task_struct(tsk);
+ set_task_state(tsk, TASK_UNINTERRUPTIBLE);
+ if (xchg(&tsk->thread.pfault_wait, 1) != 0) {
+ /* Completion interrupt was faster than the initial
+ * interrupt (swapped in a -1 for pfault_wait). Set
+ * pfault_wait back to zero and exit. This can be
+ * done safely because tsk is running in kernel
+ * mode and can't produce new pfaults. */
+ tsk->thread.pfault_wait = 0;
+ set_task_state(tsk, TASK_RUNNING);
+ put_task_struct(tsk);
+ } else
+ set_tsk_need_resched(tsk);
+ }
+}
+
+void __init pfault_irq_init(void)
+{
+ if (!MACHINE_IS_VM)
+ return;
+
+ /*
+ * Try to get pfault pseudo page faults going.
+ */
+ if (register_early_external_interrupt(0x2603, pfault_interrupt,
+ &ext_int_pfault) != 0)
+ panic("Couldn't request external interrupt 0x2603");
+
+ if (pfault_init() == 0)
+ return;
+
+ /* Tough luck, no pfault. */
+ pfault_disable = 1;
+ unregister_early_external_interrupt(0x2603, pfault_interrupt,
+ &ext_int_pfault);
+}
+#endif