linux-kernel - [PATCH] LoongArch: Fix kernel_page

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Message-ID: <20250212142046.599757-1-chenhuacai@loongson.cn>
Date: Wed, 12 Feb 2025 22:20:46 +0800
From: Huacai Chen <chenhuacai@...ngson.cn>
To: Huacai Chen <chenhuacai@...nel.org>
Cc: loongarch@...ts.linux.dev,
	Xuefeng Li <lixuefeng@...ngson.cn>,
	Guo Ren <guoren@...nel.org>,
	Xuerui Wang <kernel@...0n.name>,
	Jiaxun Yang <jiaxun.yang@...goat.com>,
	linux-kernel@...r.kernel.org,
	loongson-kernel@...ts.loongnix.cn,
	Huacai Chen <chenhuacai@...ngson.cn>
Subject: [PATCH] LoongArch: Fix kernel_page_present() for KPRANGE/XKPRANGE

Now kernel_page_present() always return true for KPRANGE/XKPRANGE
addresses, this isn't correct because hibernation (ACPI S4) use it
to distinguish whether a page is saveable. If all KPRANGE/XKPRANGE
addresses are considered as saveable, then reserved memory such as
EFI_RUNTIME_SERVICES_CODE / EFI_RUNTIME_SERVICES_DATA will also be
saved and restored.

Fix this by returning true only if the KPRANGE/XKPRANGE address is in
memblock.memory.

Signed-off-by: Huacai Chen <chenhuacai@...ngson.cn>
---
 arch/loongarch/mm/pageattr.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/arch/loongarch/mm/pageattr.c b/arch/loongarch/mm/pageattr.c
index bf8678248444..99165903908a 100644
--- a/arch/loongarch/mm/pageattr.c
+++ b/arch/loongarch/mm/pageattr.c
@@ -3,6 +3,7 @@
  * Copyright (C) 2024 Loongson Technology Corporation Limited
  */
 
+#include <linux/memblock.h>
 #include <linux/pagewalk.h>
 #include <linux/pgtable.h>
 #include <asm/set_memory.h>
@@ -167,7 +168,7 @@ bool kernel_page_present(struct page *page)
 	unsigned long addr = (unsigned long)page_address(page);
 
 	if (addr < vm_map_base)
-		return true;
+		return memblock_is_memory(__pa(addr));
 
 	pgd = pgd_offset_k(addr);
 	if (pgd_none(pgdp_get(pgd)))
-- 
2.47.1