linux-kernel - [PATCH 1/4] arch/loongarch: remove kasan_arch_is

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Message-ID: <20250812130933.71593-2-bhe@redhat.com>
Date: Tue, 12 Aug 2025 21:09:30 +0800
From: Baoquan He <bhe@...hat.com>
To: linux-mm@...ck.org
Cc: snovitoll@...il.com,
	ryabinin.a.a@...il.com,
	christophe.leroy@...roup.eu,
	hca@...ux.ibm.com,
	andreyknvl@...il.com,
	akpm@...ux-foundation.org,
	chenhuacai@...ngson.cn,
	davidgow@...gle.com,
	glider@...gle.com,
	dvyukov@...gle.com,
	alexghiti@...osinc.com,
	kasan-dev@...glegroups.com,
	loongarch@...ts.linux.dev,
	linuxppc-dev@...ts.ozlabs.org,
	linux-um@...ts.infradead.org,
	linux-kernel@...r.kernel.org,
	agordeev@...ux.ibm.com,
	Baoquan He <bhe@...hat.com>
Subject: [PATCH 1/4] arch/loongarch: remove kasan_arch_is_ready()

From: Sabyrzhan Tasbolatov <snovitoll@...il.com>

With the help of static key kasan_flag_enabled, kasan_arch_is_ready()
is not needed any more. So reomve the unneeded kasan_arch_is_ready() and
the relevant codes.

Here, move kasan_flag_enabled enabling before populating shadow of
liner mapping regions so that kasan_mem_to_shadow() can function well
just as the old variable 'kasan_early_stage' is located.

Signed-off-by: Sabyrzhan Tasbolatov <snovitoll@...il.com>
Signed-off-by: Baoquan He <bhe@...hat.com>
---
 arch/loongarch/include/asm/kasan.h |  7 -------
 arch/loongarch/mm/kasan_init.c     | 10 +++-------
 2 files changed, 3 insertions(+), 14 deletions(-)

diff --git a/arch/loongarch/include/asm/kasan.h b/arch/loongarch/include/asm/kasan.h
index 62f139a9c87d..0e50e5b5e056 100644
--- a/arch/loongarch/include/asm/kasan.h
+++ b/arch/loongarch/include/asm/kasan.h
@@ -66,7 +66,6 @@
 #define XKPRANGE_WC_SHADOW_OFFSET	(KASAN_SHADOW_START + XKPRANGE_WC_KASAN_OFFSET)
 #define XKVRANGE_VC_SHADOW_OFFSET	(KASAN_SHADOW_START + XKVRANGE_VC_KASAN_OFFSET)
 
-extern bool kasan_early_stage;
 extern unsigned char kasan_early_shadow_page[PAGE_SIZE];
 
 #define kasan_mem_to_shadow kasan_mem_to_shadow
@@ -75,12 +74,6 @@ void *kasan_mem_to_shadow(const void *addr);
 #define kasan_shadow_to_mem kasan_shadow_to_mem
 const void *kasan_shadow_to_mem(const void *shadow_addr);
 
-#define kasan_arch_is_ready kasan_arch_is_ready
-static __always_inline bool kasan_arch_is_ready(void)
-{
-	return !kasan_early_stage;
-}
-
 #define addr_has_metadata addr_has_metadata
 static __always_inline bool addr_has_metadata(const void *addr)
 {
diff --git a/arch/loongarch/mm/kasan_init.c b/arch/loongarch/mm/kasan_init.c
index 0c32eee6910f..f156cba818e6 100644
--- a/arch/loongarch/mm/kasan_init.c
+++ b/arch/loongarch/mm/kasan_init.c
@@ -40,11 +40,9 @@ static pgd_t kasan_pg_dir[PTRS_PER_PGD] __initdata __aligned(PAGE_SIZE);
 #define __pte_none(early, pte) (early ? pte_none(pte) : \
 ((pte_val(pte) & _PFN_MASK) == (unsigned long)__pa(kasan_early_shadow_page)))
 
-bool kasan_early_stage = true;
-
 void *kasan_mem_to_shadow(const void *addr)
 {
-	if (!kasan_arch_is_ready()) {
+	if (!kasan_enabled()) {
 		return (void *)(kasan_early_shadow_page);
 	} else {
 		unsigned long maddr = (unsigned long)addr;
@@ -300,7 +298,8 @@ void __init kasan_init(void)
 	kasan_populate_early_shadow(kasan_mem_to_shadow((void *)VMALLOC_START),
 					kasan_mem_to_shadow((void *)KFENCE_AREA_END));
 
-	kasan_early_stage = false;
+	/* Enable KASAN here before kasan_mem_to_shadow(). */
+	static_branch_enable(&kasan_flag_enabled);
 
 	/* Populate the linear mapping */
 	for_each_mem_range(i, &pa_start, &pa_end) {
@@ -329,9 +328,6 @@ void __init kasan_init(void)
 	csr_write64(__pa_symbol(swapper_pg_dir), LOONGARCH_CSR_PGDH);
 	local_flush_tlb_all();
 
-	/* 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("KernelAddressSanitizer initialized.\n");
-- 
2.41.0