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

The following commit:

  ee6a735: 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 <[email protected]>
Cc: Josh Poimboeuf <[email protected]>
Cc: Masami Hiramatsu <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Cc: Ricardo Neri <[email protected]>
Cc: Francis Deslauriers <[email protected]>
Cc: Oleg Nesterov <[email protected]>
Cc: Alexei Starovoitov <[email protected]>
Cc: Steven Rostedt <[email protected]>
Cc: Andy Lutomirski <[email protected]>
Cc: "H . Peter Anvin" <[email protected]>
Cc: Yonghong Song <[email protected]>
Cc: Borislav Petkov <[email protected]>
Cc: Linus Torvalds <[email protected]>
Cc: "David S . Miller" <[email protected]>
Signed-off-by: Ingo Molnar <[email protected]>

Author: Ingo Molnar

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

@@ -208,4 +208,22 @@ static inline int insn_offset_immediate(struct insn *insn)
 	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 */