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author | Masami Hiramatsu <mhiramat@redhat.com> | 2010-02-25 08:34:46 -0500 |
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committer | Ingo Molnar <mingo@elte.hu> | 2010-02-25 17:49:26 +0100 |
commit | c0f7ac3a9edde786bc129d37627953a8b8abefdf (patch) | |
tree | 8d6f2df2d1a08f2893327dd2a8b6e56525705456 /arch/x86/include/asm/kprobes.h | |
parent | 3d55cc8a058ee96291d6d45b1e35121b9920eca3 (diff) | |
download | op-kernel-dev-c0f7ac3a9edde786bc129d37627953a8b8abefdf.zip op-kernel-dev-c0f7ac3a9edde786bc129d37627953a8b8abefdf.tar.gz |
kprobes/x86: Support kprobes jump optimization on x86
Introduce x86 arch-specific optimization code, which supports
both of x86-32 and x86-64.
This code also supports safety checking, which decodes whole of
a function in which probe is inserted, and checks following
conditions before optimization:
- The optimized instructions which will be replaced by a jump instruction
don't straddle the function boundary.
- There is no indirect jump instruction, because it will jumps into
the address range which is replaced by jump operand.
- There is no jump/loop instruction which jumps into the address range
which is replaced by jump operand.
- Don't optimize kprobes if it is in functions into which fixup code will
jumps.
This uses text_poke_multibyte() which doesn't support modifying
code on NMI/MCE handler. However, since kprobes itself doesn't
support NMI/MCE code probing, it's not a problem.
Changes in v9:
- Use *_text_reserved() for checking the probe can be optimized.
- Verify jump address range is in 2G range when preparing slot.
- Backup original code when switching optimized buffer, instead of
preparing buffer, because there can be int3 of other probes in
preparing phase.
- Check kprobe is disabled in arch_check_optimized_kprobe().
- Strictly check indirect jump opcodes (ff /4, ff /5).
Changes in v6:
- Split stop_machine-based jump patching code.
- Update comments and coding style.
Changes in v5:
- Introduce stop_machine-based jump replacing.
Signed-off-by: Masami Hiramatsu <mhiramat@redhat.com>
Cc: systemtap <systemtap@sources.redhat.com>
Cc: DLE <dle-develop@lists.sourceforge.net>
Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: Jim Keniston <jkenisto@us.ibm.com>
Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Anders Kaseorg <andersk@ksplice.com>
Cc: Tim Abbott <tabbott@ksplice.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Jason Baron <jbaron@redhat.com>
Cc: Mathieu Desnoyers <compudj@krystal.dyndns.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
LKML-Reference: <20100225133446.6725.78994.stgit@localhost6.localdomain6>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'arch/x86/include/asm/kprobes.h')
-rw-r--r-- | arch/x86/include/asm/kprobes.h | 29 |
1 files changed, 29 insertions, 0 deletions
diff --git a/arch/x86/include/asm/kprobes.h b/arch/x86/include/asm/kprobes.h index eaec8ea..4ffa345 100644 --- a/arch/x86/include/asm/kprobes.h +++ b/arch/x86/include/asm/kprobes.h @@ -33,6 +33,9 @@ struct kprobe; typedef u8 kprobe_opcode_t; #define BREAKPOINT_INSTRUCTION 0xcc #define RELATIVEJUMP_OPCODE 0xe9 +#define RELATIVEJUMP_SIZE 5 +#define RELATIVECALL_OPCODE 0xe8 +#define RELATIVE_ADDR_SIZE 4 #define MAX_INSN_SIZE 16 #define MAX_STACK_SIZE 64 #define MIN_STACK_SIZE(ADDR) \ @@ -44,6 +47,17 @@ typedef u8 kprobe_opcode_t; #define flush_insn_slot(p) do { } while (0) +/* optinsn template addresses */ +extern kprobe_opcode_t optprobe_template_entry; +extern kprobe_opcode_t optprobe_template_val; +extern kprobe_opcode_t optprobe_template_call; +extern kprobe_opcode_t optprobe_template_end; +#define MAX_OPTIMIZED_LENGTH (MAX_INSN_SIZE + RELATIVE_ADDR_SIZE) +#define MAX_OPTINSN_SIZE \ + (((unsigned long)&optprobe_template_end - \ + (unsigned long)&optprobe_template_entry) + \ + MAX_OPTIMIZED_LENGTH + RELATIVEJUMP_SIZE) + extern const int kretprobe_blacklist_size; void arch_remove_kprobe(struct kprobe *p); @@ -64,6 +78,21 @@ struct arch_specific_insn { int boostable; }; +struct arch_optimized_insn { + /* copy of the original instructions */ + kprobe_opcode_t copied_insn[RELATIVE_ADDR_SIZE]; + /* detour code buffer */ + kprobe_opcode_t *insn; + /* the size of instructions copied to detour code buffer */ + size_t size; +}; + +/* Return true (!0) if optinsn is prepared for optimization. */ +static inline int arch_prepared_optinsn(struct arch_optimized_insn *optinsn) +{ + return optinsn->size; +} + struct prev_kprobe { struct kprobe *kp; unsigned long status; |