linux-kernel - [PATCH v2 09/12] arch/x86: don't initialize kasan if it's disabled

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Message-ID: <20250812124941.69508-10-bhe@redhat.com>
Date: Tue, 12 Aug 2025 20:49:38 +0800
From: Baoquan He <bhe@...hat.com>
To: linux-mm@...ck.org
Cc: ryabinin.a.a@...il.com,
	glider@...gle.com,
	andreyknvl@...il.com,
	dvyukov@...gle.com,
	vincenzo.frascino@....com,
	akpm@...ux-foundation.org,
	kasan-dev@...glegroups.com,
	linux-kernel@...r.kernel.org,
	kexec@...ts.infradead.org,
	sj@...nel.org,
	lorenzo.stoakes@...cle.com,
	elver@...gle.com,
	snovitoll@...il.com,
	Baoquan He <bhe@...hat.com>
Subject: [PATCH v2 09/12] arch/x86: don't initialize kasan if it's disabled

And also add code to enable kasan_flag_enabled, this is for later
usage.

Signed-off-by: Baoquan He <bhe@...hat.com>
---
 arch/x86/mm/kasan_init_64.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/arch/x86/mm/kasan_init_64.c b/arch/x86/mm/kasan_init_64.c
index 0539efd0d216..0f2f9311e9df 100644
--- a/arch/x86/mm/kasan_init_64.c
+++ b/arch/x86/mm/kasan_init_64.c
@@ -343,6 +343,9 @@ void __init kasan_init(void)
 	unsigned long shadow_cea_begin, shadow_cea_per_cpu_begin, shadow_cea_end;
 	int i;
 
+	if (kasan_arg_disabled)
+		return;
+
 	memcpy(early_top_pgt, init_top_pgt, sizeof(early_top_pgt));
 
 	/*
@@ -450,6 +453,9 @@ void __init kasan_init(void)
 	/* Flush TLBs again to be sure that write protection applied. */
 	__flush_tlb_all();
 
+	/* KASAN is now initialized, enable it. */
+	static_branch_enable(&kasan_flag_enabled);
+
 	init_task.kasan_depth = 0;
 	pr_info("KernelAddressSanitizer initialized\n");
 }
-- 
2.41.0