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Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
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
11const 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(addr);
17 if (fixup)
18 return fixup;
19 num = __stop_amode31_ex_table - __start_amode31_ex_table;
20 return search_extable(__start_amode31_ex_table, num, addr);
21}
22
23static 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
29static 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
38static 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
50static 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
64bool fixup_exception(struct pt_regs *regs)
65{
66 const struct exception_table_entry *ex;
67
68 ex = s390_search_extables(instruction_pointer(regs));
69 if (!ex)
70 return false;
71 switch (ex->type) {
72 case EX_TYPE_FIXUP:
73 return ex_handler_fixup(ex, regs);
74 case EX_TYPE_BPF:
75 return ex_handler_bpf(ex, regs);
76 case EX_TYPE_UA_STORE:
77 return ex_handler_ua_store(ex, regs);
78 case EX_TYPE_UA_LOAD_MEM:
79 return ex_handler_ua_load_mem(ex, regs);
80 case EX_TYPE_UA_LOAD_REG:
81 return ex_handler_ua_load_reg(ex, false, regs);
82 case EX_TYPE_UA_LOAD_REGPAIR:
83 return ex_handler_ua_load_reg(ex, true, regs);
84 }
85 panic("invalid exception table entry");
86}