4.16-stable review patch. If anyone has any objections, please let me know.
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From: Ingo Molnar mingo@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 peterz@infradead.org Cc: Josh Poimboeuf jpoimboe@redhat.com Cc: Masami Hiramatsu mhiramat@kernel.org Cc: Thomas Gleixner tglx@linutronix.de Cc: Ricardo Neri ricardo.neri-calderon@linux.intel.com Cc: Francis Deslauriers francis.deslauriers@efficios.com Cc: Oleg Nesterov oleg@redhat.com Cc: Alexei Starovoitov ast@kernel.org Cc: Steven Rostedt rostedt@goodmis.org Cc: Andy Lutomirski luto@kernel.org Cc: "H . Peter Anvin" hpa@zytor.com Cc: Yonghong Song yhs@fb.com Cc: Borislav Petkov bp@suse.de Cc: Linus Torvalds torvalds@linux-foundation.org Cc: "David S . Miller" davem@davemloft.net Signed-off-by: Ingo Molnar mingo@kernel.org Signed-off-by: Sasha Levin alexander.levin@microsoft.com Signed-off-by: Greg Kroah-Hartman gregkh@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 */