On Fri, Jul 8, 2016 at 12:35 PM, David Long <dave.l...@linaro.org> wrote: > From: Sandeepa Prabhu <sandeepa.s.pra...@gmail.com> > > Kprobes needs simulation of instructions that cannot be stepped > from a different memory location, e.g.: those instructions > that uses PC-relative addressing. In simulation, the behaviour > of the instruction is implemented using a copy of pt_regs. > > The following instruction categories are simulated: > - All branching instructions(conditional, register, and immediate) > - Literal access instructions(load-literal, adr/adrp) > > Conditional execution is limited to branching instructions in > ARM v8. If conditions at PSTATE do not match the condition fields > of opcode, the instruction is effectively NOP. > > Thanks to Will Cohen for assorted suggested changes. > > Signed-off-by: Sandeepa Prabhu <sandeepa.s.pra...@gmail.com> > Signed-off-by: William Cohen <wco...@redhat.com> > Signed-off-by: David A. Long <dave.l...@linaro.org> > Acked-by: Masami Hiramatsu <mhira...@kernel.org> > --- > arch/arm64/include/asm/probes.h | 5 +- > arch/arm64/kernel/insn.c | 1 + > arch/arm64/kernel/probes/Makefile | 3 +- > arch/arm64/kernel/probes/decode-insn.c | 33 ++++- > arch/arm64/kernel/probes/decode-insn.h | 1 + > arch/arm64/kernel/probes/kprobes.c | 53 ++++++-- > arch/arm64/kernel/probes/simulate-insn.c | 218 > +++++++++++++++++++++++++++++++ > arch/arm64/kernel/probes/simulate-insn.h | 28 ++++ > 8 files changed, 327 insertions(+), 15 deletions(-) > create mode 100644 arch/arm64/kernel/probes/simulate-insn.c > create mode 100644 arch/arm64/kernel/probes/simulate-insn.h > >
[...] > diff --git a/arch/arm64/kernel/probes/simulate-insn.c > b/arch/arm64/kernel/probes/simulate-insn.c > new file mode 100644 > index 0000000..429c333 > --- /dev/null > +++ b/arch/arm64/kernel/probes/simulate-insn.c > @@ -0,0 +1,218 @@ > +/* > + * arch/arm64/kernel/probes/simulate-insn.c > + * > + * Copyright (C) 2013 Linaro Limited. > + * > + * This program is free software; you can redistribute it and/or modify > + * it under the terms of the GNU General Public License version 2 as > + * published by the Free Software Foundation. > + * > + * This program is distributed in the hope that it will be useful, > + * but WITHOUT ANY WARRANTY; without even the implied warranty of > + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU > + * General Public License for more details. > + */ > + > +#include <linux/kernel.h> > +#include <linux/kprobes.h> > +#include <linux/module.h> Maybe I missed something, but I don't see anything modular about this code, so why include this? Paul. -- > + > +#include "simulate-insn.h" > + > +#define sign_extend(x, signbit) \ > + ((x) | (0 - ((x) & (1 << (signbit))))) > + > +#define bbl_displacement(insn) \ > + sign_extend(((insn) & 0x3ffffff) << 2, 27) > + > +#define bcond_displacement(insn) \ > + sign_extend(((insn >> 5) & 0x7ffff) << 2, 20) > + disp = ldr_displacement(opcode); > + load_addr = (s32 *) (addr + disp); > + > + set_x_reg(regs, xn, *load_addr); > + > + instruction_pointer_set(regs, instruction_pointer(regs) + 4); > +}
