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Date:   Tue, 13 Apr 2021 00:17:38 +0800
From:   Jisheng Zhang <jszhang3@mail.ustc.edu.cn>
To:     Paul Walmsley <paul.walmsley@sifive.com>,
        Palmer Dabbelt <palmer@dabbelt.com>,
        Albert Ou <aou@eecs.berkeley.edu>,
        Andrey Ryabinin <ryabinin.a.a@gmail.com>,
        Alexander Potapenko <glider@google.com>,
        Andrey Konovalov <andreyknvl@gmail.com>,
        Dmitry Vyukov <dvyukov@google.com>,
        " =?UTF-8?B?QmrDtnJuIFTDtnBlbA==?=" <bjorn@kernel.org>,
        Alexei Starovoitov <ast@kernel.org>,
        Daniel Borkmann <daniel@iogearbox.net>,
        Andrii Nakryiko <andrii@kernel.org>,
        Martin KaFai Lau <kafai@fb.com>,
        Song Liu <songliubraving@fb.com>, Yonghong Song <yhs@fb.com>,
        John Fastabend <john.fastabend@gmail.com>,
        KP Singh <kpsingh@kernel.org>,
        Luke Nelson <luke.r.nels@gmail.com>,
        Xi Wang <xi.wang@gmail.com>, Anup Patel <anup@brainfault.org>
Cc:     linux-riscv@lists.infradead.org, linux-kernel@vger.kernel.org
Subject: [PATCH v3 06/10] riscv: kprobes: Implement alloc_insn_page()
Message-ID: <20210413001738.20c8b2e0@xhacker>
In-Reply-To: <20210413001110.7209bae6@xhacker>
References: <20210413001110.7209bae6@xhacker>
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From: Jisheng Zhang <jszhang@kernel.org>

Allocate PAGE_KERNEL_READ_EXEC(read only, executable) page for kprobes
insn page. This is to prepare for STRICT_MODULE_RWX.

Signed-off-by: Jisheng Zhang <jszhang@kernel.org>
Reviewed-by: Anup Patel <anup@brainfault.org>
---
 arch/riscv/kernel/probes/kprobes.c | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/arch/riscv/kernel/probes/kprobes.c b/arch/riscv/kernel/probes/kprobes.c
index 7e2c78e2ca6b..8c1f7a30aeed 100644
--- a/arch/riscv/kernel/probes/kprobes.c
+++ b/arch/riscv/kernel/probes/kprobes.c
@@ -84,6 +84,14 @@ int __kprobes arch_prepare_kprobe(struct kprobe *p)
 	return 0;
 }
 
+void *alloc_insn_page(void)
+{
+	return  __vmalloc_node_range(PAGE_SIZE, 1, VMALLOC_START, VMALLOC_END,
+				     GFP_KERNEL, PAGE_KERNEL_READ_EXEC,
+				     VM_FLUSH_RESET_PERMS, NUMA_NO_NODE,
+				     __builtin_return_address(0));
+}
+
 /* install breakpoint in text */
 void __kprobes arch_arm_kprobe(struct kprobe *p)
 {
-- 
2.31.0