include/asm/alternative.h

1 /* SPDX-License-Identifier: GPL-2.0 */
13  * Alternative inline assembly for SMP.
18  * SMP alternatives use the same data structures as the other
20  * UP system running a SMP kernel.  The existing apply_alternatives()
21  * works fine for patching a SMP kernel for UP.
23  * The SMP alternative tables can be kept after boot and contain both
24  * UP and SMP versions of the instructions to allow switching back to
25  * SMP at runtime, when hotplugging in a new CPU, which is especially
37 		".long 671f - .\n" /* offset */		\
55 	".long 999b - .\n\t"					\
60 	s32 repl_offset;	/* offset to replacement instruction */
64 	u8  padlen;		/* length of build-time padding */
102 #define alt_slen		"662b-661b"
103 #define alt_pad_len		alt_end_marker"b-662b"
104 #define alt_total_slen		alt_end_marker"b-661b"
105 #define alt_rlen(num)		e_replacement(num)"f-"b_replacement(num)"f"
111 	".skip -(((" alt_rlen(num) ")-(" alt_slen ")) > 0) * "		\
112 		"((" alt_rlen(num) ")-(" alt_slen ")),0x90\n"		\
119  * The additional "-" is needed because gas uses a "true" value of -1.
121 #define alt_max_short(a, b)	"((" a ") ^ (((" a ") ^ (" b ")) & -(-((" a ") < (" b ")))))"
131 	".skip -((" alt_max_short(alt_rlen(num1), alt_rlen(num2)) " - (" alt_slen ")) > 0) * "	\
132 		"(" alt_max_short(alt_rlen(num1), alt_rlen(num2)) " - (" alt_slen ")), 0x90\n"	\
139 	".skip -((" alt_max_short(alt_max_short(alt_rlen(n1), alt_rlen(n2)), alt_rlen(n3))	\
140 		" - (" alt_slen ")) > 0) * "							\
142 		" - (" alt_slen ")), 0x90\n"							\
146 	" .long 661b - .\n"				/* label           */ \
147 	" .long " b_replacement(num)"f - .\n"		/* new instruction */ \