From: Vasily Gorbik <gor@linux.ibm.com>
Date: Thu, 13 Mar 2025 09:55:43 +0000 (+0100)
Subject: s390/kfence: Split kfence pool into 4k mappings in arch_kfence_init_pool()
X-Git-Tag: v6.15-rc1~113^2~1
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=caa3cd5ccd016cb28294e2b7e21fe08831e9a877;p=thirdparty%2Fkernel%2Flinux.git

s390/kfence: Split kfence pool into 4k mappings in arch_kfence_init_pool()

Since commit d08d4e7cd6bf ("s390/mm: use full 4KB page for 2KB PTE"),
there is no longer any reason to avoid splitting the kfence pool into
4k mappings in arch_kfence_init_pool(). Remove the architecture-specific
kfence_split_mapping().

Reviewed-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
---

diff --git a/arch/s390/include/asm/kfence.h b/arch/s390/include/asm/kfence.h
index e47fd8cbe7012..e95e35eb8a3f0 100644
--- a/arch/s390/include/asm/kfence.h
+++ b/arch/s390/include/asm/kfence.h
@@ -11,28 +11,17 @@
 void __kernel_map_pages(struct page *page, int numpages, int enable);
 
 static __always_inline bool arch_kfence_init_pool(void)
-{
-	return true;
-}
-
-#define arch_kfence_test_address(addr) ((addr) & PAGE_MASK)
-
-/*
- * Do not split kfence pool to 4k mapping with arch_kfence_init_pool(),
- * but earlier where page table allocations still happen with memblock.
- * Reason is that arch_kfence_init_pool() gets called when the system
- * is still in a limbo state - disabling and enabling bottom halves is
- * not yet allowed, but that is what our page_table_alloc() would do.
- */
-static __always_inline void kfence_split_mapping(void)
 {
 #ifdef CONFIG_KFENCE
 	unsigned long pool_pages = KFENCE_POOL_SIZE >> PAGE_SHIFT;
 
 	set_memory_4k((unsigned long)__kfence_pool, pool_pages);
 #endif
+	return true;
 }
 
+#define arch_kfence_test_address(addr) ((addr) & PAGE_MASK)
+
 static inline bool kfence_protect_page(unsigned long addr, bool protect)
 {
 	__kernel_map_pages(virt_to_page((void *)addr), 1, !protect);
diff --git a/arch/s390/mm/init.c b/arch/s390/mm/init.c
index 615ee245cb930..f4ac695066083 100644
--- a/arch/s390/mm/init.c
+++ b/arch/s390/mm/init.c
@@ -175,7 +175,6 @@ void __init mem_init(void)
         high_memory = (void *) __va(max_low_pfn * PAGE_SIZE);
 
 	pv_init();
-	kfence_split_mapping();
 
 	/* this will put all low memory onto the freelists */
 	memblock_free_all();