Messages in this thread | | | Date | Wed, 12 May 2021 22:58:19 +0800 | From | Jisheng Zhang <> | Subject | Re: [PATCH] riscv: kprobes: Remove redundant kprobe_step_ctx |
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On Mon, 19 Apr 2021 00:29:19 +0800 Jisheng Zhang <jszhang3@mail.ustc.edu.cn> wrote:
> From: Jisheng Zhang <jszhang@kernel.org> > > Inspired by commit ba090f9cafd5 ("arm64: kprobes: Remove redundant > kprobe_step_ctx"), the ss_pending and match_addr of kprobe_step_ctx > are redundant because those can be replaced by KPROBE_HIT_SS and > &cur_kprobe->ainsn.api.insn[0] + GET_INSN_LENGTH(cur->opcode) > respectively. > > Remove the kprobe_step_ctx to simplify the code.
Hi all,
This patch can still be applied to 5.13-rc1, could you please review? Let me know if a rebase on 5.13-rc1 is needed.
Thanks
> > Signed-off-by: Jisheng Zhang <jszhang@kernel.org> > --- > arch/riscv/include/asm/kprobes.h | 7 ------ > arch/riscv/kernel/probes/kprobes.c | 40 +++++++----------------------- > 2 files changed, 9 insertions(+), 38 deletions(-) > > diff --git a/arch/riscv/include/asm/kprobes.h b/arch/riscv/include/asm/kprobes.h > index 4647d38018f6..9ea9b5ec3113 100644 > --- a/arch/riscv/include/asm/kprobes.h > +++ b/arch/riscv/include/asm/kprobes.h > @@ -29,18 +29,11 @@ struct prev_kprobe { > unsigned int status; > }; > > -/* Single step context for kprobe */ > -struct kprobe_step_ctx { > - unsigned long ss_pending; > - unsigned long match_addr; > -}; > - > /* per-cpu kprobe control block */ > struct kprobe_ctlblk { > unsigned int kprobe_status; > unsigned long saved_status; > struct prev_kprobe prev_kprobe; > - struct kprobe_step_ctx ss_ctx; > }; > > void arch_remove_kprobe(struct kprobe *p); > diff --git a/arch/riscv/kernel/probes/kprobes.c b/arch/riscv/kernel/probes/kprobes.c > index 8c1f7a30aeed..4c1ad5536748 100644 > --- a/arch/riscv/kernel/probes/kprobes.c > +++ b/arch/riscv/kernel/probes/kprobes.c > @@ -17,7 +17,7 @@ DEFINE_PER_CPU(struct kprobe *, current_kprobe) = NULL; > DEFINE_PER_CPU(struct kprobe_ctlblk, kprobe_ctlblk); > > static void __kprobes > -post_kprobe_handler(struct kprobe_ctlblk *, struct pt_regs *); > +post_kprobe_handler(struct kprobe *, struct kprobe_ctlblk *, struct pt_regs *); > > static void __kprobes arch_prepare_ss_slot(struct kprobe *p) > { > @@ -43,7 +43,7 @@ static void __kprobes arch_simulate_insn(struct kprobe *p, struct pt_regs *regs) > p->ainsn.api.handler((u32)p->opcode, > (unsigned long)p->addr, regs); > > - post_kprobe_handler(kcb, regs); > + post_kprobe_handler(p, kcb, regs); > } > > int __kprobes arch_prepare_kprobe(struct kprobe *p) > @@ -149,21 +149,6 @@ static void __kprobes kprobes_restore_local_irqflag(struct kprobe_ctlblk *kcb, > regs->status = kcb->saved_status; > } > > -static void __kprobes > -set_ss_context(struct kprobe_ctlblk *kcb, unsigned long addr, struct kprobe *p) > -{ > - unsigned long offset = GET_INSN_LENGTH(p->opcode); > - > - kcb->ss_ctx.ss_pending = true; > - kcb->ss_ctx.match_addr = addr + offset; > -} > - > -static void __kprobes clear_ss_context(struct kprobe_ctlblk *kcb) > -{ > - kcb->ss_ctx.ss_pending = false; > - kcb->ss_ctx.match_addr = 0; > -} > - > static void __kprobes setup_singlestep(struct kprobe *p, > struct pt_regs *regs, > struct kprobe_ctlblk *kcb, int reenter) > @@ -182,8 +167,6 @@ static void __kprobes setup_singlestep(struct kprobe *p, > /* prepare for single stepping */ > slot = (unsigned long)p->ainsn.api.insn; > > - set_ss_context(kcb, slot, p); /* mark pending ss */ > - > /* IRQs and single stepping do not mix well. */ > kprobes_save_local_irqflag(kcb, regs); > > @@ -219,13 +202,8 @@ static int __kprobes reenter_kprobe(struct kprobe *p, > } > > static void __kprobes > -post_kprobe_handler(struct kprobe_ctlblk *kcb, struct pt_regs *regs) > +post_kprobe_handler(struct kprobe *cur, struct kprobe_ctlblk *kcb, struct pt_regs *regs) > { > - struct kprobe *cur = kprobe_running(); > - > - if (!cur) > - return; > - > /* return addr restore if non-branching insn */ > if (cur->ainsn.api.restore != 0) > regs->epc = cur->ainsn.api.restore; > @@ -355,16 +333,16 @@ bool __kprobes > kprobe_single_step_handler(struct pt_regs *regs) > { > struct kprobe_ctlblk *kcb = get_kprobe_ctlblk(); > + unsigned long addr = instruction_pointer(regs); > + struct kprobe *cur = kprobe_running(); > > - if ((kcb->ss_ctx.ss_pending) > - && (kcb->ss_ctx.match_addr == instruction_pointer(regs))) { > - clear_ss_context(kcb); /* clear pending ss */ > - > + if (cur && (kcb->kprobe_status & (KPROBE_HIT_SS | KPROBE_REENTER)) && > + ((unsigned long)&cur->ainsn.api.insn[0] + GET_INSN_LENGTH(cur->opcode) == addr)) { > kprobes_restore_local_irqflag(kcb, regs); > - > - post_kprobe_handler(kcb, regs); > + post_kprobe_handler(cur, kcb, regs); > return true; > } > + /* not ours, kprobes should ignore it */ > return false; > } >
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