mem.c

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/*
 * Copyright (C) 2002 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
 * Licensed under the GPL
 */

#include <stddef.h>
#include <unistd.h>
#include <errno.h>
#include <string.h>
#include <sys/mman.h>
#include <init.h>
#include <as-layout.h>
#include <mm_id.h>
#include <os.h>
#include <proc_mm.h>
#include <ptrace_user.h>
#include <registers.h>
#include <skas.h>
#include <sysdep/ptrace.h>
#include <sysdep/stub.h>

extern unsigned long batch_syscall_stub, __syscall_stub_start;

extern void wait_stub_done(int pid);

static inline unsigned long *check_init_stack(struct mm_id * mm_idp,
                          unsigned long *stack)
{
    if (stack == NULL) {
        stack = (unsigned long *) mm_idp->stack + 2;
        *stack = 0;
    }
    return stack;
}

static unsigned long syscall_regs[MAX_REG_NR];

static int __init init_syscall_regs(void)
{
    get_safe_registers(syscall_regs, NULL);
    syscall_regs[REGS_IP_INDEX] = STUB_CODE +
        ((unsigned long) &batch_syscall_stub -
         (unsigned long) &__syscall_stub_start);
    return 0;
}

__initcall(init_syscall_regs);

extern int proc_mm;

static inline long do_syscall_stub(struct mm_id * mm_idp, void **addr)
{
    int n, i;
    long ret, offset;
    unsigned long * data;
    unsigned long * syscall;
    int err, pid = mm_idp->u.pid;

    if (proc_mm)
        /* FIXME: Need to look up userspace_pid by cpu */
        pid = userspace_pid[0];

    n = ptrace_setregs(pid, syscall_regs);
    if (n < 0) {
        printk(UM_KERN_ERR "Registers - \n");
        for (i = 0; i < MAX_REG_NR; i++)
            printk(UM_KERN_ERR "\t%d\t0x%lx\n", i, syscall_regs[i]);
        panic("do_syscall_stub : PTRACE_SETREGS failed, errno = %d\n",
              -n);
    }

    err = ptrace(PTRACE_CONT, pid, 0, 0);
    if (err)
        panic("Failed to continue stub, pid = %d, errno = %d\n", pid,
              errno);

    wait_stub_done(pid);

    /*
     * When the stub stops, we find the following values on the
     * beginning of the stack:
     * (long )return_value
     * (long )offset to failed sycall-data (0, if no error)
     */
    ret = *((unsigned long *) mm_idp->stack);
    offset = *((unsigned long *) mm_idp->stack + 1);
    if (offset) {
        data = (unsigned long *)(mm_idp->stack + offset - STUB_DATA);
        printk(UM_KERN_ERR "do_syscall_stub : ret = %ld, offset = %ld, "
               "data = %p\n", ret, offset, data);
        syscall = (unsigned long *)((unsigned long)data + data[0]);
        printk(UM_KERN_ERR "do_syscall_stub: syscall %ld failed, "
               "return value = 0x%lx, expected return value = 0x%lx\n",
               syscall[0], ret, syscall[7]);
        printk(UM_KERN_ERR "    syscall parameters: "
               "0x%lx 0x%lx 0x%lx 0x%lx 0x%lx 0x%lx\n",
               syscall[1], syscall[2], syscall[3],
               syscall[4], syscall[5], syscall[6]);
        for (n = 1; n < data[0]/sizeof(long); n++) {
            if (n == 1)
                printk(UM_KERN_ERR "    additional syscall "
                       "data:");
            if (n % 4 == 1)
                printk("\n" UM_KERN_ERR "      ");
            printk("  0x%lx", data[n]);
        }
        if (n > 1)
            printk("\n");
    }
    else ret = 0;

    *addr = check_init_stack(mm_idp, NULL);

    return ret;
}

long run_syscall_stub(struct mm_id * mm_idp, int syscall,
              unsigned long *args, long expected, void **addr,
              int done)
{
    unsigned long *stack = check_init_stack(mm_idp, *addr);

    *stack += sizeof(long);
    stack += *stack / sizeof(long);

    *stack++ = syscall;
    *stack++ = args[0];
    *stack++ = args[1];
    *stack++ = args[2];
    *stack++ = args[3];
    *stack++ = args[4];
    *stack++ = args[5];
    *stack++ = expected;
    *stack = 0;

    if (!done && ((((unsigned long) stack) & ~UM_KERN_PAGE_MASK) <
             UM_KERN_PAGE_SIZE - 10 * sizeof(long))) {
        *addr = stack;
        return 0;
    }

    return do_syscall_stub(mm_idp, addr);
}

long syscall_stub_data(struct mm_id * mm_idp,
               unsigned long *data, int data_count,
               void **addr, void **stub_addr)
{
    unsigned long *stack;
    int ret = 0;

    /*
     * If *addr still is uninitialized, it *must* contain NULL.
     * Thus in this case do_syscall_stub correctly won't be called.
     */
    if ((((unsigned long) *addr) & ~UM_KERN_PAGE_MASK) >=
       UM_KERN_PAGE_SIZE - (10 + data_count) * sizeof(long)) {
        ret = do_syscall_stub(mm_idp, addr);
        /* in case of error, don't overwrite data on stack */
        if (ret)
            return ret;
    }

    stack = check_init_stack(mm_idp, *addr);
    *addr = stack;

    *stack = data_count * sizeof(long);

    memcpy(stack + 1, data, data_count * sizeof(long));

    *stub_addr = (void *)(((unsigned long)(stack + 1) &
                   ~UM_KERN_PAGE_MASK) + STUB_DATA);

    return 0;
}

int map(struct mm_id * mm_idp, unsigned long virt, unsigned long len, int prot,
    int phys_fd, unsigned long long offset, int done, void **data)
{
    int ret;

    if (proc_mm) {
        struct proc_mm_op map;
        int fd = mm_idp->u.mm_fd;

        map = ((struct proc_mm_op) { .op    = MM_MMAP,
                       .u       =
                       { .mmap  =
                     { .addr    = virt,
                       .len = len,
                       .prot    = prot,
                       .flags   = MAP_SHARED |
                       MAP_FIXED,
                       .fd  = phys_fd,
                       .offset= offset
                     } } } );
        CATCH_EINTR(ret = write(fd, &map, sizeof(map)));
        if (ret != sizeof(map)) {
            ret = -errno;
            printk(UM_KERN_ERR "map : /proc/mm map failed, "
                   "err = %d\n", -ret);
        }
        else ret = 0;
    }
    else {
        unsigned long args[] = { virt, len, prot,
                     MAP_SHARED | MAP_FIXED, phys_fd,
                     MMAP_OFFSET(offset) };

        ret = run_syscall_stub(mm_idp, STUB_MMAP_NR, args, virt,
                       data, done);
    }

    return ret;
}

int unmap(struct mm_id * mm_idp, unsigned long addr, unsigned long len,
      int done, void **data)
{
    int ret;

    if (proc_mm) {
        struct proc_mm_op unmap;
        int fd = mm_idp->u.mm_fd;

        unmap = ((struct proc_mm_op) { .op  = MM_MUNMAP,
                     .u =
                     { .munmap  =
                       { .addr  =
                         (unsigned long) addr,
                         .len       = len } } } );
        CATCH_EINTR(ret = write(fd, &unmap, sizeof(unmap)));
        if (ret != sizeof(unmap)) {
            ret = -errno;
            printk(UM_KERN_ERR "unmap - proc_mm write returned "
                   "%d\n", ret);
        }
        else ret = 0;
    }
    else {
        unsigned long args[] = { (unsigned long) addr, len, 0, 0, 0,
                     0 };

        ret = run_syscall_stub(mm_idp, __NR_munmap, args, 0,
                       data, done);
    }

    return ret;
}

int protect(struct mm_id * mm_idp, unsigned long addr, unsigned long len,
        unsigned int prot, int done, void **data)
{
    struct proc_mm_op protect;
    int ret;

    if (proc_mm) {
        int fd = mm_idp->u.mm_fd;

        protect = ((struct proc_mm_op) { .op    = MM_MPROTECT,
                       .u   =
                       { .mprotect  =
                         { .addr    =
                           (unsigned long) addr,
                           .len = len,
                           .prot    = prot } } } );

        CATCH_EINTR(ret = write(fd, &protect, sizeof(protect)));
        if (ret != sizeof(protect)) {
            ret = -errno;
            printk(UM_KERN_ERR "protect failed, err = %d", -ret);
        }
        else ret = 0;
    }
    else {
        unsigned long args[] = { addr, len, prot, 0, 0, 0 };

        ret = run_syscall_stub(mm_idp, __NR_mprotect, args, 0,
                       data, done);
    }

    return ret;
}