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https://github.com/torvalds/linux
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dc326fca2b
Clean up and unify the NOP selection infrastructure: - Make the atomic 5-byte NOP a part of the selection system. - Pick NOPs once during early boot and then be done with it. Signed-off-by: H. Peter Anvin <hpa@linux.intel.com> Cc: Tejun Heo <tj@kernel.org> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Jason Baron <jbaron@redhat.com> Link: http://lkml.kernel.org/r/1303166160-10315-3-git-send-email-hpa@linux.intel.com
52 lines
1.1 KiB
C
52 lines
1.1 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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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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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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get_online_cpus();
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mutex_lock(&text_mutex);
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text_poke_smp((void *)entry->code, &code, JUMP_LABEL_NOP_SIZE);
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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_text_poke_early(jump_label_t addr)
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{
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text_poke_early((void *)addr, ideal_nops[NOP_ATOMIC5],
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JUMP_LABEL_NOP_SIZE);
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}
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#endif
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