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51b2c07b22
Make jump labels use text_poke_bp() for text patching instead of text_poke_smp(), avoiding the need for stop_machine(). Reviewed-by: Steven Rostedt <rostedt@goodmis.org> Reviewed-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> Signed-off-by: Jiri Kosina <jkosina@suse.cz> Link: http://lkml.kernel.org/r/alpine.LNX.2.00.1307121120250.29788@pobox.suse.cz Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
72 lines
1.7 KiB
C
72 lines
1.7 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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/*
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* Make text_poke_bp() a default fallback poker.
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*
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* At the time the change is being done, just ignore whether we
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* are doing nop -> jump or jump -> nop transition, and assume
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* always nop being the 'currently valid' instruction
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*
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*/
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if (poker)
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(*poker)((void *)entry->code, &code, JUMP_LABEL_NOP_SIZE);
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else
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text_poke_bp((void *)entry->code, &code, JUMP_LABEL_NOP_SIZE,
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(void *)entry->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, NULL);
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mutex_unlock(&text_mutex);
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put_online_cpus();
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}
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__init_or_module 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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