Messages in this thread | | | Date | Fri, 20 Oct 2017 11:07:41 -0700 | From | Ricardo Neri <> | Subject | Re: [PATCH v9 17/29] x86/insn-eval: Indicate a 32-bit displacement if ModRM.mod is 0 and ModRM.rm is 101b |
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On Fri, Oct 20, 2017 at 05:44:48PM +0200, Borislav Petkov wrote: > On Tue, Oct 03, 2017 at 08:54:20PM -0700, Ricardo Neri wrote: > > Section 2.2.1.3 of the Intel 64 and IA-32 Architectures Software > > Developer's Manual volume 2A states that when ModRM.mod is zero and > > ModRM.rm is 101b, a 32-bit displacement follows the ModRM byte. This means > > that none of the registers are used in the computation of the effective > > address. A return value of -EDOM indicates callers that they should not > > use the value of registers when computing the effective address for the > > instruction. > > > > In long mode, the effective address is given by the 32-bit displacement > > plus the location of the next instruction. In protected mode, only the > > displacement is used. > > > > The instruction decoder takes care of obtaining the displacement. > > > > Cc: Dave Hansen <dave.hansen@linux.intel.com> > > Cc: Adam Buchbinder <adam.buchbinder@gmail.com> > > Cc: Colin Ian King <colin.king@canonical.com> > > Cc: Lorenzo Stoakes <lstoakes@gmail.com> > > Cc: Qiaowei Ren <qiaowei.ren@intel.com> > > Cc: Arnaldo Carvalho de Melo <acme@redhat.com> > > Cc: Masami Hiramatsu <mhiramat@kernel.org> > > Cc: Adrian Hunter <adrian.hunter@intel.com> > > Cc: Kees Cook <keescook@chromium.org> > > Cc: Thomas Garnier <thgarnie@google.com> > > Cc: Peter Zijlstra <peterz@infradead.org> > > Cc: Borislav Petkov <bp@suse.de> > > Cc: Dmitry Vyukov <dvyukov@google.com> > > Cc: Ravi V. Shankar <ravi.v.shankar@intel.com> > > Cc: x86@kernel.org > > Signed-off-by: Ricardo Neri <ricardo.neri-calderon@linux.intel.com> > > --- > > arch/x86/lib/insn-eval.c | 25 ++++++++++++++++++++++--- > > 1 file changed, 22 insertions(+), 3 deletions(-) > > Reviewed-by: Borislav Petkov <bp@suse.de>
Thank you!
BR, Ricardo
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