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mem.c

/*
 * 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 "kern_constants.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 "user.h"
#include "sysdep/ptrace.h"
#include "sysdep/stub.h"
#include "uml-config.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);
      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;

int single_count = 0;
int multi_count = 0;
int multi_op_count = 0;

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];

      multi_count++;

      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);

      if (done && *addr == NULL)
            single_count++;

      *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;
      multi_op_count++;

      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;
}

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