From: Masami Hiramatsu <mhiramat@kernel.org>
To: "Naveen N. Rao" <naveen.n.rao@linux.vnet.ibm.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>,
Ingo Molnar <mingo@kernel.org>,
Ananth N Mavinakayanahalli <ananth@linux.vnet.ibm.com>,
Masami Hiramatsu <mhiramat@kernel.org>,
linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v3 5/7] powerpc: kprobes: factor out code to emulate instruction into a helper
Date: Wed, 19 Apr 2017 23:40:25 +0900 [thread overview]
Message-ID: <20170419234025.e0bc1137a87e2ebc2b7790dd@kernel.org> (raw)
In-Reply-To: <4fbd6652c2dd8944448fd4d84efa92f20a016d3b.1492604782.git.naveen.n.rao@linux.vnet.ibm.com>
On Wed, 19 Apr 2017 18:21:04 +0530
"Naveen N. Rao" <naveen.n.rao@linux.vnet.ibm.com> wrote:
Factor out code to emulate instruction into a try_to_emulate()
helper function. This makes ...
> No functional changes.
Thanks,
>
> Acked-by: Ananth N Mavinakayanahalli <ananth@linux.vnet.ibm.com>
> Signed-off-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
> ---
> arch/powerpc/kernel/kprobes.c | 52 ++++++++++++++++++++++++++-----------------
> 1 file changed, 31 insertions(+), 21 deletions(-)
>
> diff --git a/arch/powerpc/kernel/kprobes.c b/arch/powerpc/kernel/kprobes.c
> index d743bacefa8c..46e8c1e03ce4 100644
> --- a/arch/powerpc/kernel/kprobes.c
> +++ b/arch/powerpc/kernel/kprobes.c
> @@ -206,6 +206,35 @@ void __kprobes arch_prepare_kretprobe(struct kretprobe_instance *ri,
> regs->link = (unsigned long)kretprobe_trampoline;
> }
>
> +int __kprobes try_to_emulate(struct kprobe *p, struct pt_regs *regs)
> +{
> + int ret;
> + unsigned int insn = *p->ainsn.insn;
> +
> + /* regs->nip is also adjusted if emulate_step returns 1 */
> + ret = emulate_step(regs, insn);
> + if (ret > 0) {
> + /*
> + * Once this instruction has been boosted
> + * successfully, set the boostable flag
> + */
> + if (unlikely(p->ainsn.boostable == 0))
> + p->ainsn.boostable = 1;
> + } else if (ret < 0) {
> + /*
> + * We don't allow kprobes on mtmsr(d)/rfi(d), etc.
> + * So, we should never get here... but, its still
> + * good to catch them, just in case...
> + */
> + printk("Can't step on instruction %x\n", insn);
> + BUG();
> + } else if (ret == 0)
> + /* This instruction can't be boosted */
> + p->ainsn.boostable = -1;
> +
> + return ret;
> +}
> +
> int __kprobes kprobe_handler(struct pt_regs *regs)
> {
> struct kprobe *p;
> @@ -301,18 +330,9 @@ int __kprobes kprobe_handler(struct pt_regs *regs)
>
> ss_probe:
> if (p->ainsn.boostable >= 0) {
> - unsigned int insn = *p->ainsn.insn;
> + ret = try_to_emulate(p, regs);
>
> - /* regs->nip is also adjusted if emulate_step returns 1 */
> - ret = emulate_step(regs, insn);
> if (ret > 0) {
> - /*
> - * Once this instruction has been boosted
> - * successfully, set the boostable flag
> - */
> - if (unlikely(p->ainsn.boostable == 0))
> - p->ainsn.boostable = 1;
> -
> if (p->post_handler)
> p->post_handler(p, regs, 0);
>
> @@ -320,17 +340,7 @@ int __kprobes kprobe_handler(struct pt_regs *regs)
> reset_current_kprobe();
> preempt_enable_no_resched();
> return 1;
> - } else if (ret < 0) {
> - /*
> - * We don't allow kprobes on mtmsr(d)/rfi(d), etc.
> - * So, we should never get here... but, its still
> - * good to catch them, just in case...
> - */
> - printk("Can't step on instruction %x\n", insn);
> - BUG();
> - } else if (ret == 0)
> - /* This instruction can't be boosted */
> - p->ainsn.boostable = -1;
> + }
> }
> prepare_singlestep(p, regs);
> kcb->kprobe_status = KPROBE_HIT_SS;
> --
> 2.12.1
>
--
Masami Hiramatsu <mhiramat@kernel.org>
next prev parent reply other threads:[~2017-04-19 14:40 UTC|newest]
Thread overview: 38+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-04-19 12:50 [PATCH v3 0/7] powerpc: a few kprobe fixes and refactoring Naveen N. Rao
2017-04-19 12:51 ` [PATCH v3 1/7] kprobes: convert kprobe_lookup_name() to a function Naveen N. Rao
2017-04-24 22:47 ` [v3,1/7] " Michael Ellerman
2017-04-19 12:51 ` [PATCH v3 2/7] powerpc: kprobes: fix handling of function offsets on ABIv2 Naveen N. Rao
2017-04-24 22:47 ` [v3,2/7] " Michael Ellerman
2017-04-19 12:51 ` [PATCH v3 3/7] kprobes: validate the symbol name length Naveen N. Rao
2017-04-19 14:37 ` Masami Hiramatsu
2017-04-19 16:38 ` Naveen N. Rao
2017-04-21 13:42 ` Masami Hiramatsu
2017-04-23 15:44 ` Naveen N. Rao
2017-04-25 3:18 ` Masami Hiramatsu
2017-04-20 6:08 ` Michael Ellerman
2017-04-20 7:19 ` Naveen N. Rao
2017-04-21 12:32 ` [PATCH v4 3/7] kprobes: validate the symbol name provided during probe registration Naveen N. Rao
2017-04-21 13:11 ` Paul Clarke
2017-04-21 13:25 ` Naveen N. Rao
2017-04-21 13:54 ` Masami Hiramatsu
2017-04-22 5:55 ` Michael Ellerman
2017-04-23 17:41 ` Naveen N. Rao
2017-04-21 12:33 ` [PATCH v4 4/7] powerpc/kprobes: Use safer string functions in kprobe_lookup_name() Naveen N. Rao
2017-04-21 13:33 ` Paul Clarke
2017-04-21 13:36 ` Paul Clarke
2017-04-21 13:52 ` Paul Clarke
2017-04-23 17:09 ` Naveen N. Rao
2017-04-19 12:51 ` [PATCH v3 4/7] powerpc: kprobes: use " Naveen N. Rao
2017-04-21 15:06 ` David Laight
2017-04-19 12:51 ` [PATCH v3 5/7] powerpc: kprobes: factor out code to emulate instruction into a helper Naveen N. Rao
2017-04-19 14:40 ` Masami Hiramatsu [this message]
2017-04-24 22:47 ` [v3, " Michael Ellerman
2017-04-19 12:51 ` [PATCH v3 6/7] powerpc: kprobes: emulate instructions on kprobe handler re-entry Naveen N. Rao
2017-04-19 14:43 ` Masami Hiramatsu
2017-04-19 16:42 ` Naveen N. Rao
2017-04-20 6:11 ` Michael Ellerman
2017-04-21 13:48 ` Masami Hiramatsu
2017-04-24 22:47 ` [v3, " Michael Ellerman
2017-04-19 12:51 ` [PATCH v3 7/7] powerpc: kprobes: remove duplicate saving of msr Naveen N. Rao
2017-04-19 14:43 ` Masami Hiramatsu
2017-04-23 11:53 ` [v3,7/7] " Michael Ellerman
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