[PATCH 4.16 233/279] objtool, kprobes/x86: Sync the latest <asm/insn.h> header with tools/objtool/arch/x86/include/asm/insn.h

[Greg Kroah-Hartman]

4.16-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Ingo Molnar <mingo@xxxxxxxxxx>

[ Upstream commit 4fe875e4bd3cae85ae6f6eaf77f63fabe613b66e ]

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 <peterz@xxxxxxxxxxxxx>
Cc: Josh Poimboeuf <jpoimboe@xxxxxxxxxx>
Cc: Masami Hiramatsu <mhiramat@xxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: Ricardo Neri <ricardo.neri-calderon@xxxxxxxxxxxxxxx>
Cc: Francis Deslauriers <francis.deslauriers@xxxxxxxxxxxx>
Cc: Oleg Nesterov <oleg@xxxxxxxxxx>
Cc: Alexei Starovoitov <ast@xxxxxxxxxx>
Cc: Steven Rostedt <rostedt@xxxxxxxxxxx>
Cc: Andy Lutomirski <luto@xxxxxxxxxx>
Cc: "H . Peter Anvin" <hpa@xxxxxxxxx>
Cc: Yonghong Song <yhs@xxxxxx>
Cc: Borislav Petkov <bp@xxxxxxx>
Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Cc: "David S . Miller" <davem@xxxxxxxxxxxxx>
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
Signed-off-by: Sasha Levin <alexander.levin@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
 tools/objtool/arch/x86/include/asm/insn.h |   18 ++++++++++++++++++
 1 file changed, 18 insertions(+)

--- a/tools/objtool/arch/x86/include/asm/insn.h
+++ b/tools/objtool/arch/x86/include/asm/insn.h
@@ -208,4 +208,22 @@ static inline int insn_offset_immediate(
 	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 */