objtool, kprobes/x86: Sync the latest <asm/insn.h> header with tools/objtool/arch/x86/include/asm/insn.h

The following commit:

ee6a7354a362: kprobes/x86: Prohibit probing on exception masking instructions

Modified <asm/insn.h>, adding the insn_masking_exception() function.

Sync the tooling version of the header to it, to fix this warning:

Warning: synced file at 'tools/objtool/arch/x86/include/asm/insn.h' differs from latest kernel version at 'arch/x86/include/asm/insn.h'

Cc: Peter Zijlstra <[e-mail]>
Cc: Josh Poimboeuf <[e-mail]>
Cc: Masami Hiramatsu <[e-mail]>
Cc: Thomas Gleixner <[e-mail]>
Cc: Ricardo Neri <[e-mail]>
Cc: Francis Deslauriers <[e-mail]>
Cc: Oleg Nesterov <[e-mail]>
Cc: Alexei Starovoitov <[e-mail]>
Cc: Steven Rostedt <[e-mail]>
Cc: Andy Lutomirski <[e-mail]>
Cc: "H . Peter Anvin" <[e-mail]>
Cc: Yonghong Song <[e-mail]>
Cc: Borislav Petkov <[e-mail]>
Cc: Linus Torvalds <[e-mail]>
Cc: "David S . Miller" <[e-mail]>
Signed-off-by: Ingo Molnar <[e-mail]>

tools/objtool/arch/x86/include/asm/insn.h

···
 	return insn_offset_displacement(insn) + insn->displacement.nbytes;
 }
 
+#define POP_SS_OPCODE 0x1f
+#define MOV_SREG_OPCODE 0x8e
+
+/*
+ * Intel SDM Vol.3A 6.8.3 states;
+ * "Any single-step trap that would be delivered following the MOV to SS
+ * instruction or POP to SS instruction (because EFLAGS.TF is 1) is
+ * suppressed."
+ * This function returns true if @insn is MOV SS or POP SS. On these
+ * instructions, single stepping is suppressed.
+ */
+static inline int insn_masking_exception(struct insn *insn)
+{
+	return insn->opcode.bytes[0] == POP_SS_OPCODE ||
+		(insn->opcode.bytes[0] == MOV_SREG_OPCODE &&
+		 X86_MODRM_REG(insn->modrm.bytes[0]) == 2);
+}
+
 #endif /* _ASM_X86_INSN_H */