1 | // SPDX-License-Identifier: GPL-2.0 |
2 | |
3 | #include <linux/bitfield.h> |
4 | #include <linux/extable.h> |
5 | #include <linux/string.h> |
6 | #include <linux/errno.h> |
7 | #include <linux/panic.h> |
8 | #include <asm/asm-extable.h> |
9 | #include <asm/extable.h> |
10 | |
11 | const struct exception_table_entry *s390_search_extables(unsigned long addr) |
12 | { |
13 | const struct exception_table_entry *fixup; |
14 | size_t num; |
15 | |
16 | fixup = search_exception_tables(add: addr); |
17 | if (fixup) |
18 | return fixup; |
19 | num = __stop_amode31_ex_table - __start_amode31_ex_table; |
20 | return search_extable(base: __start_amode31_ex_table, num, value: addr); |
21 | } |
22 | |
23 | static bool ex_handler_fixup(const struct exception_table_entry *ex, struct pt_regs *regs) |
24 | { |
25 | regs->psw.addr = extable_fixup(ex); |
26 | return true; |
27 | } |
28 | |
29 | static bool ex_handler_ua_store(const struct exception_table_entry *ex, struct pt_regs *regs) |
30 | { |
31 | unsigned int reg_err = FIELD_GET(EX_DATA_REG_ERR, ex->data); |
32 | |
33 | regs->gprs[reg_err] = -EFAULT; |
34 | regs->psw.addr = extable_fixup(ex); |
35 | return true; |
36 | } |
37 | |
38 | static bool ex_handler_ua_load_mem(const struct exception_table_entry *ex, struct pt_regs *regs) |
39 | { |
40 | unsigned int reg_addr = FIELD_GET(EX_DATA_REG_ADDR, ex->data); |
41 | unsigned int reg_err = FIELD_GET(EX_DATA_REG_ERR, ex->data); |
42 | size_t len = FIELD_GET(EX_DATA_LEN, ex->data); |
43 | |
44 | regs->gprs[reg_err] = -EFAULT; |
45 | memset((void *)regs->gprs[reg_addr], 0, len); |
46 | regs->psw.addr = extable_fixup(ex); |
47 | return true; |
48 | } |
49 | |
50 | static bool ex_handler_ua_load_reg(const struct exception_table_entry *ex, |
51 | bool pair, struct pt_regs *regs) |
52 | { |
53 | unsigned int reg_zero = FIELD_GET(EX_DATA_REG_ADDR, ex->data); |
54 | unsigned int reg_err = FIELD_GET(EX_DATA_REG_ERR, ex->data); |
55 | |
56 | regs->gprs[reg_err] = -EFAULT; |
57 | regs->gprs[reg_zero] = 0; |
58 | if (pair) |
59 | regs->gprs[reg_zero + 1] = 0; |
60 | regs->psw.addr = extable_fixup(ex); |
61 | return true; |
62 | } |
63 | |
64 | static bool ex_handler_zeropad(const struct exception_table_entry *ex, struct pt_regs *regs) |
65 | { |
66 | unsigned int reg_addr = FIELD_GET(EX_DATA_REG_ADDR, ex->data); |
67 | unsigned int reg_data = FIELD_GET(EX_DATA_REG_ERR, ex->data); |
68 | unsigned long data, addr, offset; |
69 | |
70 | addr = regs->gprs[reg_addr]; |
71 | offset = addr & (sizeof(unsigned long) - 1); |
72 | addr &= ~(sizeof(unsigned long) - 1); |
73 | data = *(unsigned long *)addr; |
74 | data <<= BITS_PER_BYTE * offset; |
75 | regs->gprs[reg_data] = data; |
76 | regs->psw.addr = extable_fixup(ex); |
77 | return true; |
78 | } |
79 | |
80 | bool fixup_exception(struct pt_regs *regs) |
81 | { |
82 | const struct exception_table_entry *ex; |
83 | |
84 | ex = s390_search_extables(addr: instruction_pointer(regs)); |
85 | if (!ex) |
86 | return false; |
87 | switch (ex->type) { |
88 | case EX_TYPE_FIXUP: |
89 | return ex_handler_fixup(ex, regs); |
90 | case EX_TYPE_BPF: |
91 | return ex_handler_bpf(x: ex, regs); |
92 | case EX_TYPE_UA_STORE: |
93 | return ex_handler_ua_store(ex, regs); |
94 | case EX_TYPE_UA_LOAD_MEM: |
95 | return ex_handler_ua_load_mem(ex, regs); |
96 | case EX_TYPE_UA_LOAD_REG: |
97 | return ex_handler_ua_load_reg(ex, pair: false, regs); |
98 | case EX_TYPE_UA_LOAD_REGPAIR: |
99 | return ex_handler_ua_load_reg(ex, pair: true, regs); |
100 | case EX_TYPE_ZEROPAD: |
101 | return ex_handler_zeropad(ex, regs); |
102 | } |
103 | panic(fmt: "invalid exception table entry" ); |
104 | } |
105 | |