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https://github.com/AuxXxilium/linux_dsm_epyc7002.git
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e71a5be15e
This allows jump-label entries to be cheaply updated on code which is not yet live. Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com> Acked-by: Jason Baron <jbaron@redhat.com> Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
60 lines
1.3 KiB
C
60 lines
1.3 KiB
C
/*
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* jump label x86 support
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*
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* Copyright (C) 2009 Jason Baron <jbaron@redhat.com>
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*
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*/
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#include <linux/jump_label.h>
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#include <linux/memory.h>
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#include <linux/uaccess.h>
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#include <linux/module.h>
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#include <linux/list.h>
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#include <linux/jhash.h>
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#include <linux/cpu.h>
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#include <asm/kprobes.h>
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#include <asm/alternative.h>
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#ifdef HAVE_JUMP_LABEL
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union jump_code_union {
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char code[JUMP_LABEL_NOP_SIZE];
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struct {
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char jump;
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int offset;
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} __attribute__((packed));
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};
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static void __jump_label_transform(struct jump_entry *entry,
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enum jump_label_type type,
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void *(*poker)(void *, const void *, size_t))
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{
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union jump_code_union code;
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if (type == JUMP_LABEL_ENABLE) {
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code.jump = 0xe9;
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code.offset = entry->target -
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(entry->code + JUMP_LABEL_NOP_SIZE);
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} else
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memcpy(&code, ideal_nops[NOP_ATOMIC5], JUMP_LABEL_NOP_SIZE);
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(*poker)((void *)entry->code, &code, JUMP_LABEL_NOP_SIZE);
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}
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void arch_jump_label_transform(struct jump_entry *entry,
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enum jump_label_type type)
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{
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get_online_cpus();
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mutex_lock(&text_mutex);
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__jump_label_transform(entry, type, text_poke_smp);
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mutex_unlock(&text_mutex);
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put_online_cpus();
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}
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void arch_jump_label_transform_static(struct jump_entry *entry,
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enum jump_label_type type)
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{
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__jump_label_transform(entry, type, text_poke_early);
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}
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#endif
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