xref: /OK3568_Linux_fs/kernel/arch/powerpc/include/asm/extable.h (revision 4882a59341e53eb6f0b4789bf948001014eff981)
1*4882a593Smuzhiyun /* SPDX-License-Identifier: GPL-2.0 */
2*4882a593Smuzhiyun #ifndef _ARCH_POWERPC_EXTABLE_H
3*4882a593Smuzhiyun #define _ARCH_POWERPC_EXTABLE_H
4*4882a593Smuzhiyun 
5*4882a593Smuzhiyun /*
6*4882a593Smuzhiyun  * The exception table consists of pairs of relative addresses: the first is
7*4882a593Smuzhiyun  * the address of an instruction that is allowed to fault, and the second is
8*4882a593Smuzhiyun  * the address at which the program should continue.  No registers are
9*4882a593Smuzhiyun  * modified, so it is entirely up to the continuation code to figure out what
10*4882a593Smuzhiyun  * to do.
11*4882a593Smuzhiyun  *
12*4882a593Smuzhiyun  * All the routines below use bits of fixup code that are out of line with the
13*4882a593Smuzhiyun  * main instruction path.  This means when everything is well, we don't even
14*4882a593Smuzhiyun  * have to jump over them.  Further, they do not intrude on our cache or tlb
15*4882a593Smuzhiyun  * entries.
16*4882a593Smuzhiyun  */
17*4882a593Smuzhiyun 
18*4882a593Smuzhiyun #define ARCH_HAS_RELATIVE_EXTABLE
19*4882a593Smuzhiyun 
20*4882a593Smuzhiyun struct exception_table_entry {
21*4882a593Smuzhiyun 	int insn;
22*4882a593Smuzhiyun 	int fixup;
23*4882a593Smuzhiyun };
24*4882a593Smuzhiyun 
extable_fixup(const struct exception_table_entry * x)25*4882a593Smuzhiyun static inline unsigned long extable_fixup(const struct exception_table_entry *x)
26*4882a593Smuzhiyun {
27*4882a593Smuzhiyun 	return (unsigned long)&x->fixup + x->fixup;
28*4882a593Smuzhiyun }
29*4882a593Smuzhiyun 
30*4882a593Smuzhiyun #endif
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