42 lines
1012 B
C
42 lines
1012 B
C
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// SPDX-License-Identifier: GPL-2.0
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#include <linux/uaccess.h>
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#include <asm/nospec-branch.h>
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#include <asm/abs_lowcore.h>
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#include <asm/alternative.h>
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#include <asm/facility.h>
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void __apply_alternatives(struct alt_instr *start, struct alt_instr *end, unsigned int ctx)
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{
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u8 *instr, *replacement;
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struct alt_instr *a;
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bool replace;
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/*
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* The scan order should be from start to end. A later scanned
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* alternative code can overwrite previously scanned alternative code.
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*/
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for (a = start; a < end; a++) {
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if (!(a->ctx & ctx))
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continue;
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switch (a->type) {
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case ALT_TYPE_FACILITY:
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replace = test_facility(a->data);
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break;
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case ALT_TYPE_SPEC:
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replace = nobp_enabled();
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break;
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case ALT_TYPE_LOWCORE:
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replace = have_relocated_lowcore();
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break;
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default:
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replace = false;
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}
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if (!replace)
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continue;
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instr = (u8 *)&a->instr_offset + a->instr_offset;
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replacement = (u8 *)&a->repl_offset + a->repl_offset;
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s390_kernel_write(instr, replacement, a->instrlen);
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}
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}
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