[PATCH 5/9] x86/clear_pages: add clear_pages()

Ankur Arora
2023-04-03T05:23:36Z

Add clear_pages() and define the ancillary clear_user_pages().

Signed-off-by: Ankur Arora <ankur.a.arora@oracle.com>
---
arch/x86/include/asm/page.h | 6 ++++++
arch/x86/include/asm/page_32.h | 6 ++++++
arch/x86/include/asm/page_64.h | 9 +++++++--
3 files changed, 19 insertions(+), 2 deletions(-)

diff --git a/arch/x86/include/asm/page.h b/arch/x86/include/asm/page.h
index d18e5c332cb9..03e3c69fc427 100644
--- a/arch/x86/include/asm/page.h
+++ b/arch/x86/include/asm/page.h
@@ -28,6 +28,12 @@ static inline void clear_user_page(void *page, unsigned long vaddr,
clear_page(page);
}

+static inline void clear_user_pages(void *page, unsigned long vaddr,
+ struct page *pg, unsigned int nsubpages)
+{
+ clear_pages(page, nsubpages);
+}
+
static inline void copy_user_page(void *to, void *from, unsigned long vaddr,
struct page *topage)
{
diff --git a/arch/x86/include/asm/page_32.h b/arch/x86/include/asm/page_32.h
index 580d71aca65a..3523d1150cfc 100644
--- a/arch/x86/include/asm/page_32.h
+++ b/arch/x86/include/asm/page_32.h
@@ -22,6 +22,12 @@ static inline void clear_page(void *page)
memset(page, 0, PAGE_SIZE);
}

+static inline void clear_pages(void *page, unsigned int nsubpages)
+{
+ for (int i = 0; i < nsubpages; i++)
+ clear_page(page + i * PAGE_SIZE);
+}
+
static inline void copy_page(void *to, void *from)
{
memcpy(to, from, PAGE_SIZE);
diff --git a/arch/x86/include/asm/page_64.h b/arch/x86/include/asm/page_64.h
index 7ca3bd2448c1..42f6c45206c1 100644
--- a/arch/x86/include/asm/page_64.h
+++ b/arch/x86/include/asm/page_64.h
@@ -43,9 +43,9 @@ void clear_pages_orig(void *page, unsigned int length);
void clear_pages_rep(void *page, unsigned int length);
void clear_pages_erms(void *page, unsigned int length);

-static inline void clear_page(void *page)
+static inline void clear_pages(void *page, unsigned int nsubpages)
{
- unsigned long length = PAGE_SIZE;
+ unsigned int length = nsubpages * PAGE_SIZE;
/*
* Clean up KMSAN metadata for the page being cleared. The assembly call
* below clobbers @page, so we perform unpoisoning before it.
@@ -60,6 +60,11 @@ static inline void clear_page(void *page)
: "cc", "memory", "rax", "rcx");
}

+static inline void clear_page(void *page)
+{
+ clear_pages(page, 1);
+}
+
void copy_page(void *to, void *from);

#ifdef CONFIG_X86_5LEVEL
--
2.31.1