uprobes/x86: Fix RIP-relative handling of EVEX-encoded instructions
Since instruction decoder now supports EVEX-encoded instructions, two fixes are needed to correctly handle them in uprobes. Extended bits for MODRM.rm field need to be sanitized just like we do it for VEX3, to avoid encoding wrong register for register-relative access. EVEX has _two_ extended bits: b and x. Theoretically, EVEX.x should be ignored by the CPU (since GPRs go only up to 15, not 31), but let's be paranoid here: proper encoding for register-relative access should have EVEX.x = 1. Secondly, we should fetch vex.vvvv for EVEX too. This is now super easy because instruction decoder populates vex_prefix.bytes[2] for all flavors of (e)vex encodings, even for VEX2. Signed-off-by: NDenys Vlasenko <dvlasenk@redhat.com> Acked-by: NMasami Hiramatsu <mhiramat@kernel.org> Acked-by: NSrikar Dronamraju <srikar@linux.vnet.ibm.com> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: Andy Lutomirski <luto@kernel.org> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Borislav Petkov <bp@alien8.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Jim Keniston <jkenisto@us.ibm.com> Cc: Jiri Olsa <jolsa@redhat.com> Cc: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Stephane Eranian <eranian@google.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Vince Weaver <vincent.weaver@maine.edu> Cc: linux-kernel@vger.kernel.org Cc: <stable@vger.kernel.org> # v4.1+ Fixes: 8a764a87 ("x86/asm/decoder: Create artificial 3rd byte for 2-byte VEX") Link: http://lkml.kernel.org/r/20160811154521.20469-1-dvlasenk@redhat.comSigned-off-by: NIngo Molnar <mingo@kernel.org>
Showing
想要评论请 注册 或 登录