linux-kernel - [PATCH v2 07/12] arch/powerpc: don't initialize kasan if it's disabled

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Message-ID: <20250812124941.69508-8-bhe@redhat.com>
Date: Tue, 12 Aug 2025 20:49:36 +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 07/12] arch/powerpc: don't initialize kasan if it's disabled

This includes 32bit, book3s/64 and book3e/64.

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

Signed-off-by: Baoquan He <bhe@...hat.com>
---
 arch/powerpc/mm/kasan/init_32.c        | 8 +++++++-
 arch/powerpc/mm/kasan/init_book3e_64.c | 6 ++++++
 arch/powerpc/mm/kasan/init_book3s_64.c | 6 ++++++
 3 files changed, 19 insertions(+), 1 deletion(-)

diff --git a/arch/powerpc/mm/kasan/init_32.c b/arch/powerpc/mm/kasan/init_32.c
index 03666d790a53..b0c465f3fbf5 100644
--- a/arch/powerpc/mm/kasan/init_32.c
+++ b/arch/powerpc/mm/kasan/init_32.c
@@ -141,6 +141,9 @@ void __init kasan_init(void)
 	u64 i;
 	int ret;
 
+	if (kasan_arg_disabled)
+		return;
+
 	for_each_mem_range(i, &base, &end) {
 		phys_addr_t top = min(end, total_lowmem);
 
@@ -163,6 +166,9 @@ void __init kasan_init(void)
 
 	clear_page(kasan_early_shadow_page);
 
+	/* KASAN is now initialized, enable it. */
+	static_branch_enable(&kasan_flag_enabled);
+
 	/* At this point kasan is fully initialized. Enable error messages */
 	init_task.kasan_depth = 0;
 	pr_info("KASAN init done\n");
@@ -170,7 +176,7 @@ void __init kasan_init(void)
 
 void __init kasan_late_init(void)
 {
-	if (IS_ENABLED(CONFIG_KASAN_VMALLOC))
+	if (IS_ENABLED(CONFIG_KASAN_VMALLOC) && kasan_enabled())
 		kasan_unmap_early_shadow_vmalloc();
 }
 
diff --git a/arch/powerpc/mm/kasan/init_book3e_64.c b/arch/powerpc/mm/kasan/init_book3e_64.c
index 60c78aac0f63..1e1c10467a2b 100644
--- a/arch/powerpc/mm/kasan/init_book3e_64.c
+++ b/arch/powerpc/mm/kasan/init_book3e_64.c
@@ -111,6 +111,9 @@ void __init kasan_init(void)
 	u64 i;
 	pte_t zero_pte = pfn_pte(virt_to_pfn(kasan_early_shadow_page), PAGE_KERNEL_RO);
 
+	if (kasan_arg_disabled)
+		return;
+
 	for_each_mem_range(i, &start, &end)
 		kasan_init_phys_region(phys_to_virt(start), phys_to_virt(end));
 
@@ -125,6 +128,9 @@ void __init kasan_init(void)
 
 	memset(kasan_early_shadow_page, 0, PAGE_SIZE);
 
+	/* KASAN is now initialized, enable it. */
+	static_branch_enable(&kasan_flag_enabled);
+
 	/* Enable error messages */
 	init_task.kasan_depth = 0;
 	pr_info("KASAN init done\n");
diff --git a/arch/powerpc/mm/kasan/init_book3s_64.c b/arch/powerpc/mm/kasan/init_book3s_64.c
index 7d959544c077..9c5cf2354c8b 100644
--- a/arch/powerpc/mm/kasan/init_book3s_64.c
+++ b/arch/powerpc/mm/kasan/init_book3s_64.c
@@ -56,6 +56,9 @@ void __init kasan_init(void)
 	u64 i;
 	pte_t zero_pte = pfn_pte(virt_to_pfn(kasan_early_shadow_page), PAGE_KERNEL);
 
+	if (kasan_arg_disabled)
+		return;
+
 	if (!early_radix_enabled()) {
 		pr_warn("KASAN not enabled as it requires radix!");
 		return;
@@ -94,6 +97,9 @@ void __init kasan_init(void)
 
 	static_branch_inc(&powerpc_kasan_enabled_key);
 
+	/* KASAN is now initialized, enable it. */
+	static_branch_enable(&kasan_flag_enabled);
+
 	/* Enable error messages */
 	init_task.kasan_depth = 0;
 	pr_info("KASAN init done\n");
-- 
2.41.0