4.14-stable review patch. If anyone has any objections, please let me know.
------------------
From: Ingo Molnar <mi...@kernel.org>
[ 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 <pet...@infradead.org>
Cc: Josh Poimboeuf <jpoim...@redhat.com>
Cc: Masami Hiramatsu <mhira...@kernel.org>
Cc: Thomas Gleixner <t...@linutronix.de>
Cc: Ricardo Neri <ricardo.neri-calde...@linux.intel.com>
Cc: Francis Deslauriers <francis.deslauri...@efficios.com>
Cc: Oleg Nesterov <o...@redhat.com>
Cc: Alexei Starovoitov <a...@kernel.org>
Cc: Steven Rostedt <rost...@goodmis.org>
Cc: Andy Lutomirski <l...@kernel.org>
Cc: "H . Peter Anvin" <h...@zytor.com>
Cc: Yonghong Song <y...@fb.com>
Cc: Borislav Petkov <b...@suse.de>
Cc: Linus Torvalds <torva...@linux-foundation.org>
Cc: "David S . Miller" <da...@davemloft.net>
Signed-off-by: Ingo Molnar <mi...@kernel.org>
Signed-off-by: Sasha Levin <alexander.le...@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gre...@linuxfoundation.org>
---
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 */
