1*8b1d7239SHelge Deller /* SPDX-License-Identifier: GPL-2.0 */
2*8b1d7239SHelge Deller #ifndef __PARISC_EXTABLE_H
3*8b1d7239SHelge Deller #define __PARISC_EXTABLE_H
4*8b1d7239SHelge Deller
5*8b1d7239SHelge Deller #include <asm/ptrace.h>
6*8b1d7239SHelge Deller #include <linux/compiler.h>
7*8b1d7239SHelge Deller
8*8b1d7239SHelge Deller /*
9*8b1d7239SHelge Deller * The exception table consists of three addresses:
10*8b1d7239SHelge Deller *
11*8b1d7239SHelge Deller * - A relative address to the instruction that is allowed to fault.
12*8b1d7239SHelge Deller * - A relative address at which the program should continue (fixup routine)
13*8b1d7239SHelge Deller * - An asm statement which specifies which CPU register will
14*8b1d7239SHelge Deller * receive -EFAULT when an exception happens if the lowest bit in
15*8b1d7239SHelge Deller * the fixup address is set.
16*8b1d7239SHelge Deller *
17*8b1d7239SHelge Deller * Note: The register specified in the err_opcode instruction will be
18*8b1d7239SHelge Deller * modified at runtime if a fault happens. Register %r0 will be ignored.
19*8b1d7239SHelge Deller *
20*8b1d7239SHelge Deller * Since relative addresses are used, 32bit values are sufficient even on
21*8b1d7239SHelge Deller * 64bit kernel.
22*8b1d7239SHelge Deller */
23*8b1d7239SHelge Deller
24*8b1d7239SHelge Deller struct pt_regs;
25*8b1d7239SHelge Deller int fixup_exception(struct pt_regs *regs);
26*8b1d7239SHelge Deller
27*8b1d7239SHelge Deller #define ARCH_HAS_RELATIVE_EXTABLE
28*8b1d7239SHelge Deller struct exception_table_entry {
29*8b1d7239SHelge Deller int insn; /* relative address of insn that is allowed to fault. */
30*8b1d7239SHelge Deller int fixup; /* relative address of fixup routine */
31*8b1d7239SHelge Deller int err_opcode; /* sample opcode with register which holds error code */
32*8b1d7239SHelge Deller };
33*8b1d7239SHelge Deller
34*8b1d7239SHelge Deller #define ASM_EXCEPTIONTABLE_ENTRY( fault_addr, except_addr, opcode )\
35*8b1d7239SHelge Deller ".section __ex_table,\"aw\"\n" \
36*8b1d7239SHelge Deller ".align 4\n" \
37*8b1d7239SHelge Deller ".word (" #fault_addr " - .), (" #except_addr " - .)\n" \
38*8b1d7239SHelge Deller opcode "\n" \
39*8b1d7239SHelge Deller ".previous\n"
40*8b1d7239SHelge Deller
41*8b1d7239SHelge Deller /*
42*8b1d7239SHelge Deller * ASM_EXCEPTIONTABLE_ENTRY_EFAULT() creates a special exception table entry
43*8b1d7239SHelge Deller * (with lowest bit set) for which the fault handler in fixup_exception() will
44*8b1d7239SHelge Deller * load -EFAULT on fault into the register specified by the err_opcode instruction,
45*8b1d7239SHelge Deller * and zeroes the target register in case of a read fault in get_user().
46*8b1d7239SHelge Deller */
47*8b1d7239SHelge Deller #define ASM_EXCEPTIONTABLE_VAR(__err_var) \
48*8b1d7239SHelge Deller int __err_var = 0
49*8b1d7239SHelge Deller #define ASM_EXCEPTIONTABLE_ENTRY_EFAULT( fault_addr, except_addr, register )\
50*8b1d7239SHelge Deller ASM_EXCEPTIONTABLE_ENTRY( fault_addr, except_addr + 1, "or %%r0,%%r0," register)
51*8b1d7239SHelge Deller
swap_ex_entry_fixup(struct exception_table_entry * a,struct exception_table_entry * b,struct exception_table_entry tmp,int delta)52*8b1d7239SHelge Deller static inline void swap_ex_entry_fixup(struct exception_table_entry *a,
53*8b1d7239SHelge Deller struct exception_table_entry *b,
54*8b1d7239SHelge Deller struct exception_table_entry tmp,
55*8b1d7239SHelge Deller int delta)
56*8b1d7239SHelge Deller {
57*8b1d7239SHelge Deller a->fixup = b->fixup + delta;
58*8b1d7239SHelge Deller b->fixup = tmp.fixup - delta;
59*8b1d7239SHelge Deller a->err_opcode = b->err_opcode;
60*8b1d7239SHelge Deller b->err_opcode = tmp.err_opcode;
61*8b1d7239SHelge Deller }
62*8b1d7239SHelge Deller #define swap_ex_entry_fixup swap_ex_entry_fixup
63*8b1d7239SHelge Deller
64*8b1d7239SHelge Deller #endif
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