From: Liao Chang <liaochang1@huawei.com>
To: <catalin.marinas@arm.com>, <will@kernel.org>, <guoren@kernel.org>,
<paul.walmsley@sifive.com>, <palmer@dabbelt.com>,
<aou@eecs.berkeley.edu>, <mhiramat@kernel.org>,
<rostedt@goodmis.org>, <maz@kernel.org>,
<alexandru.elisei@arm.com>, <liaochang1@huawei.com>
Cc: <linux-arm-kernel@lists.infradead.org>,
<linux-kernel@vger.kernel.org>, <linux-csky@vger.kernel.org>,
<linux-riscv@lists.infradead.org>
Subject: [PATCH 1/3] riscv/kprobe: Optimize the performance of patching single-step slot
Date: Tue, 27 Sep 2022 10:24:33 +0800 [thread overview]
Message-ID: <20220927022435.129965-2-liaochang1@huawei.com> (raw)
In-Reply-To: <20220927022435.129965-1-liaochang1@huawei.com>
Single-step slot would not be used until kprobe is enabled, that means
no race condition occurs on it under SMP, hence it is safe to pacth ss
slot without stopping machine.
Acked-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Signed-off-by: Liao Chang <liaochang1@huawei.com>
---
arch/riscv/kernel/probes/kprobes.c | 8 +++++---
1 file changed, 5 insertions(+), 3 deletions(-)
diff --git a/arch/riscv/kernel/probes/kprobes.c b/arch/riscv/kernel/probes/kprobes.c
index e6e950b7cf32..bc1f39b96e41 100644
--- a/arch/riscv/kernel/probes/kprobes.c
+++ b/arch/riscv/kernel/probes/kprobes.c
@@ -24,12 +24,14 @@ post_kprobe_handler(struct kprobe *, struct kprobe_ctlblk *, struct pt_regs *);
static void __kprobes arch_prepare_ss_slot(struct kprobe *p)
{
unsigned long offset = GET_INSN_LENGTH(p->opcode);
+ kprobe_opcode_t slot[MAX_INSN_SIZE];
p->ainsn.api.restore = (unsigned long)p->addr + offset;
- patch_text(p->ainsn.api.insn, p->opcode);
- patch_text((void *)((unsigned long)(p->ainsn.api.insn) + offset),
- __BUG_INSN_32);
+ memcpy(slot, &p->opcode, offset);
+ *(kprobe_opcode_t *)((unsigned long)slot + offset) = __BUG_INSN_32;
+ patch_text_nosync(p->ainsn.api.insn, slot,
+ offset + GET_INSN_LENGTH(__BUG_INSN_32));
}
static void __kprobes arch_prepare_simulate(struct kprobe *p)
--
2.17.1
next prev parent reply other threads:[~2022-09-27 2:28 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-09-27 2:24 [PATCH V4 0/3] kprobe: Optimize the performance of patching ss Liao Chang
2022-09-27 2:24 ` Liao Chang [this message]
2022-09-27 2:24 ` [PATCH 2/3] csky/kprobe: Optimize the performance of patching single-step slot Liao Chang
2022-09-27 2:24 ` [PATCH 3/3] arm64/kprobe: " Liao Chang
2022-09-29 16:50 ` Catalin Marinas
2022-09-30 1:02 ` liaochang (A)
2022-09-30 8:15 ` Catalin Marinas
2022-09-30 16:25 ` (subset) [PATCH V4 0/3] kprobe: Optimize the performance of patching ss Catalin Marinas
-- strict thread matches above, loose matches on Subject: below --
2022-09-23 8:46 [PATCH V3 " Liao Chang
2022-09-23 8:46 ` [PATCH 1/3] riscv/kprobe: Optimize the performance of patching single-step slot Liao Chang
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