linux-kernel - [PATCH] x86/kprobes: Simplify alloc_insn_page() with __vmalloc_node

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Message-ID: <20210413180231.19b72601@xhacker.debian>
Date:   Tue, 13 Apr 2021 18:03:24 +0800
From:   Jisheng Zhang <Jisheng.Zhang@...aptics.com>
To:     Thomas Gleixner <tglx@...utronix.de>,
        Ingo Molnar <mingo@...hat.com>, Borislav Petkov <bp@...en8.de>,
        x86@...nel.org, "H. Peter Anvin" <hpa@...or.com>,
        Masami Hiramatsu <mhiramat@...nel.org>,
        Jiri Olsa <jolsa@...hat.com>
Cc:     linux-kernel@...r.kernel.org
Subject: [PATCH] x86/kprobes: Simplify alloc_insn_page() with 
 __vmalloc_node_range

Use the __vmalloc_node_range() to simplify x86's alloc_insn_page()
implementation.

Signed-off-by: Jisheng Zhang <Jisheng.Zhang@...aptics.com>
---
 arch/x86/kernel/kprobes/core.c | 24 ++++--------------------
 1 file changed, 4 insertions(+), 20 deletions(-)

diff --git a/arch/x86/kernel/kprobes/core.c b/arch/x86/kernel/kprobes/core.c
index df776cdca327..75081f3dbe44 100644
--- a/arch/x86/kernel/kprobes/core.c
+++ b/arch/x86/kernel/kprobes/core.c
@@ -383,26 +383,10 @@ static int prepare_boost(kprobe_opcode_t *buf, struct kprobe *p,
 /* Make page to RO mode when allocate it */
 void *alloc_insn_page(void)
 {
-	void *page;
-
-	page = module_alloc(PAGE_SIZE);
-	if (!page)
-		return NULL;
-
-	set_vm_flush_reset_perms(page);
-	/*
-	 * First make the page read-only, and only then make it executable to
-	 * prevent it from being W+X in between.
-	 */
-	set_memory_ro((unsigned long)page, 1);
-
-	/*
-	 * TODO: Once additional kernel code protection mechanisms are set, ensure
-	 * that the page was not maliciously altered and it is still zeroed.
-	 */
-	set_memory_x((unsigned long)page, 1);
-
-	return page;
+	return __vmalloc_node_range(PAGE_SIZE, PAGE_SIZE, VMALLOC_START,
+			VMALLOC_END, GFP_KERNEL, PAGE_KERNEL_ROX,
+			VM_FLUSH_RESET_PERMS, NUMA_NO_NODE,
+			__builtin_return_address(0));
 }
 
 /* Recover page to RW mode before releasing it */
-- 
2.31.0