os-Linux/skas/mem.c

0001 // SPDX-License-Identifier: GPL-2.0
0002 /*
0003  * Copyright (C) 2002 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
0004  */
0005
0006 #include <stddef.h>
0007 #include <unistd.h>
0008 #include <errno.h>
0009 #include <string.h>
0010 #include <sys/mman.h>
0011 #include <init.h>
0012 #include <as-layout.h>
0013 #include <mm_id.h>
0014 #include <os.h>
0015 #include <ptrace_user.h>
0016 #include <registers.h>
0017 #include <skas.h>
0018 #include <sysdep/ptrace.h>
0019 #include <sysdep/stub.h>
0020
0021 extern char batch_syscall_stub[], __syscall_stub_start[];
0022
0023 extern void wait_stub_done(int pid);
0024
0025 static inline unsigned long *check_init_stack(struct mm_id * mm_idp,
0026                           unsigned long *stack)
0027 {
0028     if (stack == NULL) {
0029         stack = (unsigned long *) mm_idp->stack + 2;
0030         *stack = 0;
0031     }
0032     return stack;
0033 }
0034
0035 static unsigned long syscall_regs[MAX_REG_NR];
0036
0037 static int __init init_syscall_regs(void)
0038 {
0039     get_safe_registers(syscall_regs, NULL);
0040     syscall_regs[REGS_IP_INDEX] = STUB_CODE +
0041         ((unsigned long) batch_syscall_stub -
0042          (unsigned long) __syscall_stub_start);
0043     syscall_regs[REGS_SP_INDEX] = STUB_DATA;
0044
0045     return 0;
0046 }
0047
0048 __initcall(init_syscall_regs);
0049
0050 static inline long do_syscall_stub(struct mm_id * mm_idp, void **addr)
0051 {
0052     int n, i;
0053     long ret, offset;
0054     unsigned long * data;
0055     unsigned long * syscall;
0056     int err, pid = mm_idp->u.pid;
0057
0058     n = ptrace_setregs(pid, syscall_regs);
0059     if (n < 0) {
0060         printk(UM_KERN_ERR "Registers - \n");
0061         for (i = 0; i < MAX_REG_NR; i++)
0062             printk(UM_KERN_ERR "\t%d\t0x%lx\n", i, syscall_regs[i]);
0063         panic("do_syscall_stub : PTRACE_SETREGS failed, errno = %d\n",
0064               -n);
0065     }
0066
0067     err = ptrace(PTRACE_CONT, pid, 0, 0);
0068     if (err)
0069         panic("Failed to continue stub, pid = %d, errno = %d\n", pid,
0070               errno);
0071
0072     wait_stub_done(pid);
0073
0074     /*
0075      * When the stub stops, we find the following values on the
0076      * beginning of the stack:
0077      * (long )return_value
0078      * (long )offset to failed sycall-data (0, if no error)
0079      */
0080     ret = *((unsigned long *) mm_idp->stack);
0081     offset = *((unsigned long *) mm_idp->stack + 1);
0082     if (offset) {
0083         data = (unsigned long *)(mm_idp->stack + offset - STUB_DATA);
0084         printk(UM_KERN_ERR "do_syscall_stub : ret = %ld, offset = %ld, "
0085                "data = %p\n", ret, offset, data);
0086         syscall = (unsigned long *)((unsigned long)data + data[0]);
0087         printk(UM_KERN_ERR "do_syscall_stub: syscall %ld failed, "
0088                "return value = 0x%lx, expected return value = 0x%lx\n",
0089                syscall[0], ret, syscall[7]);
0090         printk(UM_KERN_ERR "    syscall parameters: "
0091                "0x%lx 0x%lx 0x%lx 0x%lx 0x%lx 0x%lx\n",
0092                syscall[1], syscall[2], syscall[3],
0093                syscall[4], syscall[5], syscall[6]);
0094         for (n = 1; n < data[0]/sizeof(long); n++) {
0095             if (n == 1)
0096                 printk(UM_KERN_ERR "    additional syscall "
0097                        "data:");
0098             if (n % 4 == 1)
0099                 printk("\n" UM_KERN_ERR "      ");
0100             printk("  0x%lx", data[n]);
0101         }
0102         if (n > 1)
0103             printk("\n");
0104     }
0105     else ret = 0;
0106
0107     *addr = check_init_stack(mm_idp, NULL);
0108
0109     return ret;
0110 }
0111
0112 long run_syscall_stub(struct mm_id * mm_idp, int syscall,
0113               unsigned long *args, long expected, void **addr,
0114               int done)
0115 {
0116     unsigned long *stack = check_init_stack(mm_idp, *addr);
0117
0118     *stack += sizeof(long);
0119     stack += *stack / sizeof(long);
0120
0121     *stack++ = syscall;
0122     *stack++ = args[0];
0123     *stack++ = args[1];
0124     *stack++ = args[2];
0125     *stack++ = args[3];
0126     *stack++ = args[4];
0127     *stack++ = args[5];
0128     *stack++ = expected;
0129     *stack = 0;
0130
0131     if (!done && ((((unsigned long) stack) & ~UM_KERN_PAGE_MASK) <
0132              UM_KERN_PAGE_SIZE - 10 * sizeof(long))) {
0133         *addr = stack;
0134         return 0;
0135     }
0136
0137     return do_syscall_stub(mm_idp, addr);
0138 }
0139
0140 long syscall_stub_data(struct mm_id * mm_idp,
0141                unsigned long *data, int data_count,
0142                void **addr, void **stub_addr)
0143 {
0144     unsigned long *stack;
0145     int ret = 0;
0146
0147     /*
0148      * If *addr still is uninitialized, it *must* contain NULL.
0149      * Thus in this case do_syscall_stub correctly won't be called.
0150      */
0151     if ((((unsigned long) *addr) & ~UM_KERN_PAGE_MASK) >=
0152        UM_KERN_PAGE_SIZE - (10 + data_count) * sizeof(long)) {
0153         ret = do_syscall_stub(mm_idp, addr);
0154         /* in case of error, don't overwrite data on stack */
0155         if (ret)
0156             return ret;
0157     }
0158
0159     stack = check_init_stack(mm_idp, *addr);
0160     *addr = stack;
0161
0162     *stack = data_count * sizeof(long);
0163
0164     memcpy(stack + 1, data, data_count * sizeof(long));
0165
0166     *stub_addr = (void *)(((unsigned long)(stack + 1) &
0167                    ~UM_KERN_PAGE_MASK) + STUB_DATA);
0168
0169     return 0;
0170 }
0171
0172 int map(struct mm_id * mm_idp, unsigned long virt, unsigned long len, int prot,
0173     int phys_fd, unsigned long long offset, int done, void **data)
0174 {
0175     int ret;
0176     unsigned long args[] = { virt, len, prot,
0177                  MAP_SHARED | MAP_FIXED, phys_fd,
0178                  MMAP_OFFSET(offset) };
0179
0180     ret = run_syscall_stub(mm_idp, STUB_MMAP_NR, args, virt,
0181                    data, done);
0182
0183     return ret;
0184 }
0185
0186 int unmap(struct mm_id * mm_idp, unsigned long addr, unsigned long len,
0187       int done, void **data)
0188 {
0189     int ret;
0190     unsigned long args[] = { (unsigned long) addr, len, 0, 0, 0,
0191                  0 };
0192
0193     ret = run_syscall_stub(mm_idp, __NR_munmap, args, 0,
0194                    data, done);
0195
0196     return ret;
0197 }
0198
0199 int protect(struct mm_id * mm_idp, unsigned long addr, unsigned long len,
0200         unsigned int prot, int done, void **data)
0201 {
0202     int ret;
0203     unsigned long args[] = { addr, len, prot, 0, 0, 0 };
0204
0205     ret = run_syscall_stub(mm_idp, __NR_mprotect, args, 0,
0206                    data, done);
0207
0208     return ret;
0209 }