Messages in this thread | | | Date | Mon, 18 Oct 2021 19:49:41 +0300 | From | "Kirill A. Shutemov" <> | Subject | Re: [PATCH 2/3] x86/insn-eval: Introduce insn_decode_mmio() |
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On Mon, Oct 18, 2021 at 05:53:49PM +0200, Peter Zijlstra wrote: > On Mon, Oct 18, 2021 at 06:33:32PM +0300, Kirill A. Shutemov wrote: > > > diff --git a/arch/x86/lib/insn-eval.c b/arch/x86/lib/insn-eval.c > > index fbaa3fa24bde..2ab29d8d6731 100644 > > --- a/arch/x86/lib/insn-eval.c > > +++ b/arch/x86/lib/insn-eval.c > > @@ -1559,3 +1559,85 @@ bool insn_decode_from_regs(struct insn *insn, struct pt_regs *regs, > > > > return true; > > } > > + > > +/** > > + * insn_decode_mmio() - Decode a MMIO instruction > > + * @insn: Structure to store decoded instruction > > + * @bytes: Returns size of memory operand > > + * > > + * Decodes instruction that used for Memory-mapped I/O. > > + * > > + * Returns: > > + * > > + * Type of the instruction. Size of the memory operand is stored in > > + * @bytes. If decode failed, MMIO_DECODE_FAILED returned. > > + */ > > +enum mmio_type insn_decode_mmio(struct insn *insn, int *bytes) > > +{ > > + int type = MMIO_DECODE_FAILED; > > + > > + *bytes = 0; > > + > > + insn_get_opcode(insn); > > insn_get_opcode() can fail. Either you assume it's already called and > don't call it, or you can't assume anything and get to do error > handling.
Fair enough. I will return MMIO_DECODE_FAILED if insn_get_opcode() fails.
BTW, looks like is_string_insn() suffers from the same issue. Not sure how to fix it though.
-- Kirill A. Shutemov
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