76 lines
1.7 KiB
C
76 lines
1.7 KiB
C
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// SPDX-License-Identifier: GPL-2.0
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#include <linux/module.h>
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#include <linux/cpu.h>
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#include <linux/smp.h>
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#include <asm/text-patching.h>
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#include <asm/alternative.h>
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#include <asm/facility.h>
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#include <asm/nospec-branch.h>
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static int __initdata_or_module alt_instr_disabled;
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static int __init disable_alternative_instructions(char *str)
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{
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alt_instr_disabled = 1;
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return 0;
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}
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early_param("noaltinstr", disable_alternative_instructions);
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static void __init_or_module __apply_alternatives(struct alt_instr *start,
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struct alt_instr *end)
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{
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struct alt_instr *a;
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u8 *instr, *replacement;
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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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instr = (u8 *)&a->instr_offset + a->instr_offset;
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replacement = (u8 *)&a->repl_offset + a->repl_offset;
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if (!__test_facility(a->facility, alt_stfle_fac_list))
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continue;
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if (unlikely(a->instrlen % 2)) {
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WARN_ONCE(1, "cpu alternatives instructions length is "
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"odd, skipping patching\n");
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continue;
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}
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s390_kernel_write(instr, replacement, a->instrlen);
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}
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}
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void __init_or_module apply_alternatives(struct alt_instr *start,
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struct alt_instr *end)
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{
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if (!alt_instr_disabled)
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__apply_alternatives(start, end);
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}
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extern struct alt_instr __alt_instructions[], __alt_instructions_end[];
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void __init apply_alternative_instructions(void)
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{
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apply_alternatives(__alt_instructions, __alt_instructions_end);
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}
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static void do_sync_core(void *info)
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{
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sync_core();
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}
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void text_poke_sync(void)
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{
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on_each_cpu(do_sync_core, NULL, 1);
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}
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void text_poke_sync_lock(void)
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{
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cpus_read_lock();
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text_poke_sync();
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cpus_read_unlock();
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}
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