1 // SPDX-License-Identifier: GPL-2.0 <<
2 /* 1 /*
3 * Copyright (C) 2020-2022 Loongson Technology !! 2 * arch/ppc/mm/extable.c
>> 3 *
>> 4 * from arch/i386/mm/extable.c
4 */ 5 */
5 #include <linux/bitfield.h> <<
6 #include <linux/extable.h> <<
7 #include <linux/uaccess.h> <<
8 #include <asm/asm-extable.h> <<
9 #include <asm/branch.h> <<
10 6
11 static inline unsigned long !! 7 #include <linux/config.h>
12 get_ex_fixup(const struct exception_table_entr !! 8 #include <linux/module.h>
13 { !! 9 #include <linux/init.h>
14 return ((unsigned long)&ex->fixup + ex !! 10 #include <asm/uaccess.h>
15 } <<
16 11
17 static inline void regs_set_gpr(struct pt_regs !! 12 extern struct exception_table_entry __start___ex_table[];
18 unsigned int o !! 13 extern struct exception_table_entry __stop___ex_table[];
19 { <<
20 if (offset && offset <= MAX_REG_OFFSET <<
21 *(unsigned long *)((unsigned l <<
22 } <<
23 14
24 static bool ex_handler_fixup(const struct exce !! 15 /*
25 struct pt_regs *r !! 16 * The exception table needs to be sorted because we use the macros
>> 17 * which put things into the exception table in a variety of segments
>> 18 * such as the prep, pmac, chrp, etc. segments as well as the init
>> 19 * segment and the main kernel text segment.
>> 20 */
>> 21 static inline void
>> 22 sort_ex_table(struct exception_table_entry *start,
>> 23 struct exception_table_entry *finish)
26 { 24 {
27 regs->csr_era = get_ex_fixup(ex); !! 25 struct exception_table_entry el, *p, *q;
28 26
29 return true; !! 27 /* insertion sort */
>> 28 for (p = start + 1; p < finish; ++p) {
>> 29 /* start .. p-1 is sorted */
>> 30 if (p[0].insn < p[-1].insn) {
>> 31 /* move element p down to its right place */
>> 32 el = *p;
>> 33 q = p;
>> 34 do {
>> 35 /* el comes before q[-1], move q[-1] up one */
>> 36 q[0] = q[-1];
>> 37 --q;
>> 38 } while (q > start && el.insn < q[-1].insn);
>> 39 *q = el;
>> 40 }
>> 41 }
30 } 42 }
31 43
32 static bool ex_handler_uaccess_err_zero(const !! 44 void __init
33 struct !! 45 sort_exception_table(void)
34 { 46 {
35 int reg_err = FIELD_GET(EX_DATA_REG_ER !! 47 sort_ex_table(__start___ex_table, __stop___ex_table);
36 int reg_zero = FIELD_GET(EX_DATA_REG_Z <<
37 <<
38 regs_set_gpr(regs, reg_err * sizeof(un <<
39 regs_set_gpr(regs, reg_zero * sizeof(u <<
40 regs->csr_era = get_ex_fixup(ex); <<
41 <<
42 return true; <<
43 } 48 }
44 49
45 bool fixup_exception(struct pt_regs *regs) !! 50 /* Simple binary search */
>> 51 const struct exception_table_entry *
>> 52 search_extable(const struct exception_table_entry *first,
>> 53 const struct exception_table_entry *last,
>> 54 unsigned long value)
46 { 55 {
47 const struct exception_table_entry *ex !! 56 while (first <= last) {
48 !! 57 const struct exception_table_entry *mid;
49 ex = search_exception_tables(exception !! 58 long diff;
50 if (!ex) !! 59
51 return false; !! 60 mid = (last - first) / 2 + first;
52 !! 61 diff = mid->insn - value;
53 switch (ex->type) { !! 62 if (diff == 0)
54 case EX_TYPE_FIXUP: !! 63 return mid;
55 return ex_handler_fixup(ex, re !! 64 else if (diff < 0)
56 case EX_TYPE_UACCESS_ERR_ZERO: !! 65 first = mid+1;
57 return ex_handler_uaccess_err_ !! 66 else
58 case EX_TYPE_BPF: !! 67 last = mid-1;
59 return ex_handler_bpf(ex, regs !! 68 }
60 } !! 69 return NULL;
61 <<
62 BUG(); <<
63 } 70 }
64 71
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