1 | /* |
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2 | * Kernel exception handling table support. Derived from arch/alpha/mm/extable.c. |
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3 | * |
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4 | * Copyright (C) 1998, 1999, 2001-2002, 2004 Hewlett-Packard Co |
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5 | * David Mosberger-Tang <davidm@hpl.hp.com> |
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6 | */ |
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7 | |
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8 | #include <linux/config.h> |
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9 | #include <linux/sort.h> |
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10 | |
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11 | #include <asm/uaccess.h> |
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12 | #include <asm/module.h> |
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13 | |
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14 | static int cmp_ex(const void *a, const void *b) |
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15 | { |
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16 | const struct exception_table_entry *l = a, *r = b; |
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17 | u64 lip = (u64) &l->addr + l->addr; |
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18 | u64 rip = (u64) &r->addr + r->addr; |
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19 | |
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20 | /* avoid overflow */ |
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21 | if (lip > rip) |
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22 | return 1; |
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23 | if (lip < rip) |
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24 | return -1; |
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25 | return 0; |
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26 | } |
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27 | |
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28 | static void swap_ex(void *a, void *b, int size) |
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29 | { |
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30 | struct exception_table_entry *l = a, *r = b, tmp; |
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31 | u64 delta = (u64) r - (u64) l; |
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32 | |
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33 | tmp = *l; |
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34 | l->addr = r->addr + delta; |
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35 | l->cont = r->cont + delta; |
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36 | r->addr = tmp.addr - delta; |
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37 | r->cont = tmp.cont - delta; |
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38 | } |
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39 | |
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40 | /* |
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41 | * Sort the exception table. It's usually already sorted, but there |
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42 | * may be unordered entries due to multiple text sections (such as the |
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43 | * .init text section). Note that the exception-table-entries contain |
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44 | * location-relative addresses, which requires a bit of care during |
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45 | * sorting to avoid overflows in the offset members (e.g., it would |
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46 | * not be safe to make a temporary copy of an exception-table entry on |
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47 | * the stack, because the stack may be more than 2GB away from the |
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48 | * exception-table). |
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49 | */ |
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50 | void sort_extable (struct exception_table_entry *start, |
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51 | struct exception_table_entry *finish) |
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52 | { |
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53 | sort(start, finish - start, sizeof(struct exception_table_entry), |
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54 | cmp_ex, swap_ex); |
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55 | } |
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56 | |
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57 | const struct exception_table_entry * |
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58 | search_extable (const struct exception_table_entry *first, |
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59 | const struct exception_table_entry *last, |
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60 | unsigned long ip) |
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61 | { |
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62 | const struct exception_table_entry *mid; |
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63 | unsigned long mid_ip; |
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64 | long diff; |
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65 | |
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66 | while (first <= last) { |
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67 | mid = &first[(last - first)/2]; |
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68 | mid_ip = (u64) &mid->addr + mid->addr; |
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69 | diff = mid_ip - ip; |
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70 | if (diff == 0) |
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71 | return mid; |
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72 | else if (diff < 0) |
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73 | first = mid + 1; |
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74 | else |
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75 | last = mid - 1; |
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76 | } |
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77 | return NULL; |
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78 | } |
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79 | |
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80 | void |
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81 | ia64_handle_exception (struct pt_regs *regs, const struct exception_table_entry *e) |
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82 | { |
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83 | long fix = (u64) &e->cont + e->cont; |
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84 | |
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85 | regs->r8 = -EFAULT; |
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86 | if (fix & 4) |
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87 | regs->r9 = 0; |
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88 | regs->cr_iip = fix & ~0xf; |
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89 | ia64_psr(regs)->ri = fix & 0x3; /* set continuation slot number */ |
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90 | } |
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