Messages in this thread |  | | Date | Sat, 29 May 2021 11:40:37 -0700 (PDT) | Subject | Re: [PATCH] riscv: kprobes: Remove redundant kprobe_step_ctx | From | Palmer Dabbelt <> |
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On Wed, 12 May 2021 07:58:19 PDT (-0700), jszhang3@mail.ustc.edu.cn wrote: > 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.
Sorry, I missed this one. This is on for-next.
> > 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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