On Wed, 25 Jan 2017 22:07:16 -0800 Ricardo Neri <[email protected]> wrote:
> Hi Masami, > > On Thu, 2017-01-26 at 11:11 +0900, Masami Hiramatsu wrote: > > On Wed, 25 Jan 2017 12:23:47 -0800 > > Ricardo Neri <[email protected]> wrote: > > > > > The function insn_get_reg_offset requires a type to indicate whether > > > the returned offset is that given by by the ModRM or the SIB byte. > > > Callers of this function would need the definition of the type struct. > > > This is not needed. Instead, auxiliary functions can be defined for > > > this purpose. > > > > > > When the operand is a register, the emulation code for User-Mode > > > Instruction Prevention needs to know the offset of the register indicated > > > in the r/m part of the ModRM byte. Thus, start by adding an auxiliary > > > function for this purpose. > > > > Hmm, why wouldn't you just rename it to insn_get_reg_offset() and export it? > > Do you mean exporting the structure that I mention above? The problem > that I am trying to solve is that callers sometimes want to know the > offset of the register encoded in the SiB or the ModRM bytes. I could > use something > > insn_get_reg_offset(insn, regs, INSN_TYPE_MODRM) > insn_get_reg_offset(insn, regs, INSN_TYPE_SIB) > > Instead, I opted for > > insn_get_reg_offset_rm(insn, regs) > insn_get_reg_offset_sib(insn, regs) > > to avoid exposing an enum with the INSN_TYPE_MODRM, INSN_TYPE_SIB. OK, if so, I think you should export both of them at once, not only insn_get_reg_offset_rm(). Thank you, > > If you feel that the former makes more sense, I can change the > implementation. > > Thanks and BR, > Ricardo > > > > Thank you, > > > > > > > > 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/include/asm/insn-kernel.h | 1 + > > > arch/x86/lib/insn-kernel.c | 5 +++++ > > > 2 files changed, 6 insertions(+) > > > > > > diff --git a/arch/x86/include/asm/insn-kernel.h > > > b/arch/x86/include/asm/insn-kernel.h > > > index aef416a..3f34649 100644 > > > --- a/arch/x86/include/asm/insn-kernel.h > > > +++ b/arch/x86/include/asm/insn-kernel.h > > > @@ -12,5 +12,6 @@ > > > #include <asm/ptrace.h> > > > > > > void __user *insn_get_addr_ref(struct insn *insn, struct pt_regs *regs); > > > +int insn_get_reg_offset_rm(struct insn *insn, struct pt_regs *regs); > > > > > > #endif /* _ASM_X86_INSN_KERNEL_H */ > > > diff --git a/arch/x86/lib/insn-kernel.c b/arch/x86/lib/insn-kernel.c > > > index 8072abe..267cab4 100644 > > > --- a/arch/x86/lib/insn-kernel.c > > > +++ b/arch/x86/lib/insn-kernel.c > > > @@ -95,6 +95,11 @@ static int get_reg_offset(struct insn *insn, struct > > > pt_regs *regs, > > > return regoff[regno]; > > > } > > > > > > +int insn_get_reg_offset_rm(struct insn *insn, struct pt_regs *regs) > > > +{ > > > + return get_reg_offset(insn, regs, REG_TYPE_RM); > > > +} > > > + > > > /* > > > * return the address being referenced be instruction > > > * for rm=3 returning the content of the rm reg > > > -- > > > 2.9.3 > > > > > > > > > -- Masami Hiramatsu <[email protected]> -- To unsubscribe from this list: send the line "unsubscribe linux-msdos" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
