On Fri, Aug 18, 2017 at 05:27:52PM -0700, Ricardo Neri wrote: > String instructions are special because, in protected mode, the linear > address is always obtained via the ES segment register in operands that > use the (E)DI register; the DS segment register in operands that use > the (E)SI register. Furthermore, segment override prefixes are ignored > when calculating a linear address involving the (E)DI register; segment > override prefixes can be used when calculating linear addresses involving > the (E)SI register. > > It follows that linear addresses are calculated differently for the case of > string instructions. The purpose of this utility function is to identify > such instructions for callers to determine a linear address correctly. > > Note that this function only identifies string instructions; it does not > determine what segment register to use in the address computation. That is > left to callers. A subsequent commmit introduces a function to determine > the segment register to use given the instruction, operands and > segment override prefixes. > > Cc: Dave Hansen <[email protected]> > Cc: Adam Buchbinder <[email protected]> > Cc: Colin Ian King <[email protected]> > Cc: Lorenzo Stoakes <[email protected]> > Cc: Qiaowei Ren <[email protected]> > Cc: Arnaldo Carvalho de Melo <[email protected]> > Cc: Masami Hiramatsu <[email protected]> > Cc: Adrian Hunter <[email protected]> > Cc: Kees Cook <[email protected]> > Cc: Thomas Garnier <[email protected]> > Cc: Peter Zijlstra <[email protected]> > Cc: Borislav Petkov <[email protected]> > Cc: Dmitry Vyukov <[email protected]> > Cc: Ravi V. Shankar <[email protected]> > Cc: [email protected] > Signed-off-by: Ricardo Neri <[email protected]> > --- > arch/x86/lib/insn-eval.c | 26 ++++++++++++++++++++++++++ > 1 file changed, 26 insertions(+)
Reviewed-by: Borislav Petkov <[email protected]> -- Regards/Gruss, Boris. SUSE Linux GmbH, GF: Felix Imendörffer, Jane Smithard, Graham Norton, HRB 21284 (AG Nürnberg) --
