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// SPDX-License-Identifier: GPL-2.0
#include <linux/uaccess.h>
#include <asm/nospec-branch.h>
#include <asm/abs_lowcore.h>
#include <asm/alternative.h>
#include <asm/facility.h>
void __apply_alternatives(struct alt_instr *start, struct alt_instr *end, unsigned int ctx)
{
u8 *instr, *replacement;
struct alt_instr *a;
bool replace;
/*
* The scan order should be from start to end. A later scanned
* alternative code can overwrite previously scanned alternative code.
*/
for (a = start; a < end; a++) {
if (!(a->ctx & ctx))
continue;
switch (a->type) {
case ALT_TYPE_FACILITY:
replace = test_facility(a->data);
break;
case ALT_TYPE_SPEC:
replace = nobp_enabled();
break;
case ALT_TYPE_LOWCORE:
replace = have_relocated_lowcore();
break;
default:
replace = false;
}
if (!replace)
continue;
instr = (u8 *)&a->instr_offset + a->instr_offset;
replacement = (u8 *)&a->repl_offset + a->repl_offset;
s390_kernel_write(instr, replacement, a->instrlen);
}
}
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