Messages in this thread | | | Date | Mon, 22 Dec 2014 15:40:48 +0530 | Subject | Re: [PATCH v3 1/5] arm64: Kprobes with single stepping support | From | Pratyush Anand <> |
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Hi Dave,
On Tue, Nov 18, 2014 at 12:02 PM, David Long <dave.long@linaro.org> wrote: > From: Sandeepa Prabhu <sandeepa.prabhu@linaro.org> > > Add support for basic kernel probes(kprobes) and jump probes > (jprobes) for ARM64.
Some part of the code can be reused for uprobes as well. I think, there would still be next revision. So, if you can re-factor those parts in v4.
[...]
> +++ b/arch/arm64/include/asm/probes.h > @@ -0,0 +1,50 @@ > +/* > + * arch/arm64/include/asm/probes.h > + * > + * 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. > + */ > +#ifndef _ARM_PROBES_H > +#define _ARM_PROBES_H > + > +struct kprobe; > +struct arch_specific_insn; > + > +typedef u32 kprobe_opcode_t; > +typedef unsigned long (kprobes_pstate_check_t)(unsigned long); > +typedef unsigned long > +(kprobes_condition_check_t)(struct kprobe *p, struct pt_regs *);
To be used for uprobe: p->opcode and p->ainsn can be passed in stead of p.
> +typedef void > +(kprobes_prepare_t)(struct kprobe *, struct arch_specific_insn *);
ditto.. can pass p->opcode in stead of p.
> +typedef void (kprobes_handler_t) (u32 opcode, long addr, struct pt_regs *); > + > +enum pc_restore_type { > + NO_RESTORE, > + RESTORE_PC, > +}; > + > +struct kprobe_pc_restore { > + enum pc_restore_type type; > + unsigned long addr; > +}; > + > +/* architecture specific copy of original instruction */ > +struct arch_specific_insn { > + kprobe_opcode_t *insn; > + kprobes_pstate_check_t *pstate_cc; > + kprobes_condition_check_t *check_condn; > + kprobes_prepare_t *prepare; > + kprobes_handler_t *handler; > + /* restore address after step xol */ > + struct kprobe_pc_restore restore; > +};
Probably it would be better to keep name as probe_xxxx in stead of kprobe_xxxx.
> + > +#endif
[...]
> diff --git a/arch/arm64/kernel/kprobes-arm64.c b/arch/arm64/kernel/kprobes-arm64.c
I think most of the stuff of this file can be used for uprobe. So what about keeping name as probes-arm64.c
> new file mode 100644 > index 0000000..30d1c14
[...]
[...]
> +enum kprobe_insn __kprobes > +arm_kprobe_decode_insn(kprobe_opcode_t insn, struct arch_specific_insn *asi) > +{ > + return kprobe_decode_insn(insn, asi, aarch64_decode_table); > +}
may be we can replace kprobe to probe for the above function as well.
[...]
> +/* > + * arch/arm64/kernel/kprobes.h > + * > + * 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. > + */ > + > +#ifndef _ARM_KERNEL_KPROBES_H > +#define _ARM_KERNEL_KPROBES_H > + > +/* BRK opcodes with ESR encoding */ > +#define BRK64_ESR_MASK 0xFFFF > +#define BRK64_ESR_KPROBES 0x0004 > +#define BRK64_OPCODE_KPROBES 0xD4200080 /* "brk 0x4" */ > +#define ARCH64_NOP_OPCODE 0xD503201F
Probably these definitions can be kept in asm/insn.h. There we can add another BRK64_OPCODE_UPROBES with different brk code.
~Pratyush
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