From: Huacai Chen <chenhuacai@loongson.cn>
Date: Thu, 13 Feb 2025 04:02:35 +0000 (+0800)
Subject: LoongArch: Fix kernel_page_present() for KPRANGE/XKPRANGE
X-Git-Url: https://www.infradead.org/git/?a=commitdiff_plain;h=619b52777a4972bdb6ddf86ac54c6f68a47b51c4;p=users%2Fwilly%2Fpagecache.git

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@loongson.cn>
---

diff --git a/arch/loongarch/mm/pageattr.c b/arch/loongarch/mm/pageattr.c
index bf86782484440..99165903908a4 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)))