mirror of
https://github.com/torvalds/linux.git
synced 2024-12-11 21:52:04 +00:00
faf79934e6
jgnop mnemonic is only available since binutils 2.36,
kernel minimal required version is 2.23. Stick to brcl
to avoid build errors.
Reported-by: Nathan Chancellor <nathan@kernel.org>
Fixes: 4afeb67071 ("s390/alternatives: use instructions instead of byte patterns")
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
115 lines
3.1 KiB
C
115 lines
3.1 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
|
|
#ifndef _ASM_S390_ALTERNATIVE_ASM_H
|
|
#define _ASM_S390_ALTERNATIVE_ASM_H
|
|
|
|
#ifdef __ASSEMBLY__
|
|
|
|
/*
|
|
* Check the length of an instruction sequence. The length may not be larger
|
|
* than 254 bytes and it has to be divisible by 2.
|
|
*/
|
|
.macro alt_len_check start,end
|
|
.if ( \end - \start ) > 254
|
|
.error "cpu alternatives does not support instructions blocks > 254 bytes\n"
|
|
.endif
|
|
.if ( \end - \start ) % 2
|
|
.error "cpu alternatives instructions length is odd\n"
|
|
.endif
|
|
.endm
|
|
|
|
/*
|
|
* Issue one struct alt_instr descriptor entry (need to put it into
|
|
* the section .altinstructions, see below). This entry contains
|
|
* enough information for the alternatives patching code to patch an
|
|
* instruction. See apply_alternatives().
|
|
*/
|
|
.macro alt_entry orig_start, orig_end, alt_start, alt_end, feature
|
|
.long \orig_start - .
|
|
.long \alt_start - .
|
|
.word \feature
|
|
.byte \orig_end - \orig_start
|
|
.byte \alt_end - \alt_start
|
|
.endm
|
|
|
|
/*
|
|
* Fill up @bytes with nops. The macro emits 6-byte nop instructions
|
|
* for the bulk of the area, possibly followed by a 4-byte and/or
|
|
* a 2-byte nop if the size of the area is not divisible by 6.
|
|
*/
|
|
.macro alt_pad_fill bytes
|
|
.rept ( \bytes ) / 6
|
|
brcl 0,0
|
|
.endr
|
|
.rept ( \bytes ) % 6 / 4
|
|
nop
|
|
.endr
|
|
.rept ( \bytes ) % 6 % 4 / 2
|
|
nopr
|
|
.endr
|
|
.endm
|
|
|
|
/*
|
|
* Fill up @bytes with nops. If the number of bytes is larger
|
|
* than 6, emit a jg instruction to branch over all nops, then
|
|
* fill an area of size (@bytes - 6) with nop instructions.
|
|
*/
|
|
.macro alt_pad bytes
|
|
.if ( \bytes > 0 )
|
|
.if ( \bytes > 6 )
|
|
jg . + \bytes
|
|
alt_pad_fill \bytes - 6
|
|
.else
|
|
alt_pad_fill \bytes
|
|
.endif
|
|
.endif
|
|
.endm
|
|
|
|
/*
|
|
* Define an alternative between two instructions. If @feature is
|
|
* present, early code in apply_alternatives() replaces @oldinstr with
|
|
* @newinstr. ".skip" directive takes care of proper instruction padding
|
|
* in case @newinstr is longer than @oldinstr.
|
|
*/
|
|
.macro ALTERNATIVE oldinstr, newinstr, feature
|
|
.pushsection .altinstr_replacement,"ax"
|
|
770: \newinstr
|
|
771: .popsection
|
|
772: \oldinstr
|
|
773: alt_len_check 770b, 771b
|
|
alt_len_check 772b, 773b
|
|
alt_pad ( ( 771b - 770b ) - ( 773b - 772b ) )
|
|
774: .pushsection .altinstructions,"a"
|
|
alt_entry 772b, 774b, 770b, 771b, \feature
|
|
.popsection
|
|
.endm
|
|
|
|
/*
|
|
* Define an alternative between two instructions. If @feature is
|
|
* present, early code in apply_alternatives() replaces @oldinstr with
|
|
* @newinstr. ".skip" directive takes care of proper instruction padding
|
|
* in case @newinstr is longer than @oldinstr.
|
|
*/
|
|
.macro ALTERNATIVE_2 oldinstr, newinstr1, feature1, newinstr2, feature2
|
|
.pushsection .altinstr_replacement,"ax"
|
|
770: \newinstr1
|
|
771: \newinstr2
|
|
772: .popsection
|
|
773: \oldinstr
|
|
774: alt_len_check 770b, 771b
|
|
alt_len_check 771b, 772b
|
|
alt_len_check 773b, 774b
|
|
.if ( 771b - 770b > 772b - 771b )
|
|
alt_pad ( ( 771b - 770b ) - ( 774b - 773b ) )
|
|
.else
|
|
alt_pad ( ( 772b - 771b ) - ( 774b - 773b ) )
|
|
.endif
|
|
775: .pushsection .altinstructions,"a"
|
|
alt_entry 773b, 775b, 770b, 771b,\feature1
|
|
alt_entry 773b, 775b, 771b, 772b,\feature2
|
|
.popsection
|
|
.endm
|
|
|
|
#endif /* __ASSEMBLY__ */
|
|
|
|
#endif /* _ASM_S390_ALTERNATIVE_ASM_H */
|