arch/um/os-Linux/skas/mem.c

   1 /*
   2  * Copyright (C) 2002 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
   3  * Licensed under the GPL
   4  */
   5
   6 #include <stddef.h>
   7 #include <unistd.h>
   8 #include <errno.h>
   9 #include <string.h>
  10 #include <sys/mman.h>
  11 #include <init.h>
  12 #include <as-layout.h>
  13 #include <mm_id.h>
  14 #include <os.h>
  15 #include <ptrace_user.h>
  16 #include <registers.h>
  17 #include <skas.h>
  18 #include <sysdep/ptrace.h>
  19 #include <sysdep/stub.h>
  20
  21 extern char batch_syscall_stub[], __syscall_stub_start[];
  22
  23 extern void wait_stub_done(int pid);
  24
  25 static inline unsigned long *check_init_stack(struct mm_id * mm_idp,
  26                                               unsigned long *stack)
  27 {
  28         if (stack == NULL) {
  29                 stack = (unsigned long *) mm_idp->stack + 2;
  30                 *stack = 0;
  31         }
  32         return stack;
  33 }
  34
  35 static unsigned long syscall_regs[MAX_REG_NR];
  36
  37 static int __init init_syscall_regs(void)
  38 {
  39         get_safe_registers(syscall_regs, NULL);
  40         syscall_regs[REGS_IP_INDEX] = STUB_CODE +
  41                 ((unsigned long) batch_syscall_stub -
  42                  (unsigned long) __syscall_stub_start);
  43         return 0;
  44 }
  45
  46 __initcall(init_syscall_regs);
  47
  48 static inline long do_syscall_stub(struct mm_id * mm_idp, void **addr)
  49 {
  50         int n, i;
  51         long ret, offset;
  52         unsigned long * data;
  53         unsigned long * syscall;
  54         int err, pid = mm_idp->u.pid;
  55
  56         n = ptrace_setregs(pid, syscall_regs);
  57         if (n < 0) {
  58                 printk(UM_KERN_ERR "Registers - \n");
  59                 for (i = 0; i < MAX_REG_NR; i++)
  60                         printk(UM_KERN_ERR "\t%d\t0x%lx\n", i, syscall_regs[i]);
  61                 panic("do_syscall_stub : PTRACE_SETREGS failed, errno = %d\n",
  62                       -n);
  63         }
  64
  65         err = ptrace(PTRACE_CONT, pid, 0, 0);
  66         if (err)
  67                 panic("Failed to continue stub, pid = %d, errno = %d\n", pid,
  68                       errno);
  69
  70         wait_stub_done(pid);
  71
  72         /*
  73          * When the stub stops, we find the following values on the
  74          * beginning of the stack:
  75          * (long )return_value
  76          * (long )offset to failed sycall-data (0, if no error)
  77          */
  78         ret = *((unsigned long *) mm_idp->stack);
  79         offset = *((unsigned long *) mm_idp->stack + 1);
  80         if (offset) {
  81                 data = (unsigned long *)(mm_idp->stack + offset - STUB_DATA);
  82                 printk(UM_KERN_ERR "do_syscall_stub : ret = %ld, offset = %ld, "
  83                        "data = %p\n", ret, offset, data);
  84                 syscall = (unsigned long *)((unsigned long)data + data[0]);
  85                 printk(UM_KERN_ERR "do_syscall_stub: syscall %ld failed, "
  86                        "return value = 0x%lx, expected return value = 0x%lx\n",
  87                        syscall[0], ret, syscall[7]);
  88                 printk(UM_KERN_ERR "    syscall parameters: "
  89                        "0x%lx 0x%lx 0x%lx 0x%lx 0x%lx 0x%lx\n",
  90                        syscall[1], syscall[2], syscall[3],
  91                        syscall[4], syscall[5], syscall[6]);
  92                 for (n = 1; n < data[0]/sizeof(long); n++) {
  93                         if (n == 1)
  94                                 printk(UM_KERN_ERR "    additional syscall "
  95                                        "data:");
  96                         if (n % 4 == 1)
  97                                 printk("\n" UM_KERN_ERR "      ");
  98                         printk("  0x%lx", data[n]);
  99                 }
 100                 if (n > 1)
 101                         printk("\n");
 102         }
 103         else ret = 0;
 104
 105         *addr = check_init_stack(mm_idp, NULL);
 106
 107         return ret;
 108 }
 109
 110 long run_syscall_stub(struct mm_id * mm_idp, int syscall,
 111                       unsigned long *args, long expected, void **addr,
 112                       int done)
 113 {
 114         unsigned long *stack = check_init_stack(mm_idp, *addr);
 115
 116         *stack += sizeof(long);
 117         stack += *stack / sizeof(long);
 118
 119         *stack++ = syscall;
 120         *stack++ = args[0];
 121         *stack++ = args[1];
 122         *stack++ = args[2];
 123         *stack++ = args[3];
 124         *stack++ = args[4];
 125         *stack++ = args[5];
 126         *stack++ = expected;
 127         *stack = 0;
 128
 129         if (!done && ((((unsigned long) stack) & ~UM_KERN_PAGE_MASK) <
 130                      UM_KERN_PAGE_SIZE - 10 * sizeof(long))) {
 131                 *addr = stack;
 132                 return 0;
 133         }
 134
 135         return do_syscall_stub(mm_idp, addr);
 136 }
 137
 138 long syscall_stub_data(struct mm_id * mm_idp,
 139                        unsigned long *data, int data_count,
 140                        void **addr, void **stub_addr)
 141 {
 142         unsigned long *stack;
 143         int ret = 0;
 144
 145         /*
 146          * If *addr still is uninitialized, it *must* contain NULL.
 147          * Thus in this case do_syscall_stub correctly won't be called.
 148          */
 149         if ((((unsigned long) *addr) & ~UM_KERN_PAGE_MASK) >=
 150            UM_KERN_PAGE_SIZE - (10 + data_count) * sizeof(long)) {
 151                 ret = do_syscall_stub(mm_idp, addr);
 152                 /* in case of error, don't overwrite data on stack */
 153                 if (ret)
 154                         return ret;
 155         }
 156
 157         stack = check_init_stack(mm_idp, *addr);
 158         *addr = stack;
 159
 160         *stack = data_count * sizeof(long);
 161
 162         memcpy(stack + 1, data, data_count * sizeof(long));
 163
 164         *stub_addr = (void *)(((unsigned long)(stack + 1) &
 165                                ~UM_KERN_PAGE_MASK) + STUB_DATA);
 166
 167         return 0;
 168 }
 169
 170 int map(struct mm_id * mm_idp, unsigned long virt, unsigned long len, int prot,
 171         int phys_fd, unsigned long long offset, int done, void **data)
 172 {
 173         int ret;
 174         unsigned long args[] = { virt, len, prot,
 175                                  MAP_SHARED | MAP_FIXED, phys_fd,
 176                                  MMAP_OFFSET(offset) };
 177
 178         ret = run_syscall_stub(mm_idp, STUB_MMAP_NR, args, virt,
 179                                data, done);
 180
 181         return ret;
 182 }
 183
 184 int unmap(struct mm_id * mm_idp, unsigned long addr, unsigned long len,
 185           int done, void **data)
 186 {
 187         int ret;
 188         unsigned long args[] = { (unsigned long) addr, len, 0, 0, 0,
 189                                  0 };
 190
 191         ret = run_syscall_stub(mm_idp, __NR_munmap, args, 0,
 192                                data, done);
 193
 194         return ret;
 195 }
 196
 197 int protect(struct mm_id * mm_idp, unsigned long addr, unsigned long len,
 198             unsigned int prot, int done, void **data)
 199 {
 200         int ret;
 201         unsigned long args[] = { addr, len, prot, 0, 0, 0 };
 202
 203         ret = run_syscall_stub(mm_idp, __NR_mprotect, args, 0,
 204                                data, done);
 205
 206         return ret;
 207 }