[PATCH v2 1/3] ARM: mm: Provide set_memory_valid()

From: Kefeng Wang
Date: Wed Nov 03 2021 - 09:26:40 EST


This function validates and invalidates PTE entries, it will be used
in the later patch.

Signed-off-by: Kefeng Wang <wangkefeng.wang@xxxxxxxxxx>
---
arch/arm/include/asm/set_memory.h | 1 +
arch/arm/mm/pageattr.c | 42 +++++++++++++++++++++++--------
2 files changed, 33 insertions(+), 10 deletions(-)

diff --git a/arch/arm/include/asm/set_memory.h b/arch/arm/include/asm/set_memory.h
index ec17fc0fda7a..0211b9c5b14d 100644
--- a/arch/arm/include/asm/set_memory.h
+++ b/arch/arm/include/asm/set_memory.h
@@ -11,6 +11,7 @@ int set_memory_ro(unsigned long addr, int numpages);
int set_memory_rw(unsigned long addr, int numpages);
int set_memory_x(unsigned long addr, int numpages);
int set_memory_nx(unsigned long addr, int numpages);
+int set_memory_valid(unsigned long addr, int numpages, int enable);
#else
static inline int set_memory_ro(unsigned long addr, int numpages) { return 0; }
static inline int set_memory_rw(unsigned long addr, int numpages) { return 0; }
diff --git a/arch/arm/mm/pageattr.c b/arch/arm/mm/pageattr.c
index 9790ae3a8c68..c3c34fe714b0 100644
--- a/arch/arm/mm/pageattr.c
+++ b/arch/arm/mm/pageattr.c
@@ -32,14 +32,31 @@ static bool in_range(unsigned long start, unsigned long size,
size <= range_end - start;
}

+/*
+ * This function assumes that the range is mapped with PAGE_SIZE pages.
+ */
+static int __change_memory_common(unsigned long start, unsigned long size,
+ pgprot_t set_mask, pgprot_t clear_mask)
+{
+ struct page_change_data data;
+ int ret;
+
+ data.set_mask = set_mask;
+ data.clear_mask = clear_mask;
+
+ ret = apply_to_page_range(&init_mm, start, size, change_page_range,
+ &data);
+
+ flush_tlb_kernel_range(start, start + size);
+ return ret;
+}
+
static int change_memory_common(unsigned long addr, int numpages,
pgprot_t set_mask, pgprot_t clear_mask)
{
unsigned long start = addr & PAGE_MASK;
unsigned long end = PAGE_ALIGN(addr) + numpages * PAGE_SIZE;
unsigned long size = end - start;
- int ret;
- struct page_change_data data;

WARN_ON_ONCE(start != addr);

@@ -50,14 +67,7 @@ static int change_memory_common(unsigned long addr, int numpages,
!in_range(start, size, VMALLOC_START, VMALLOC_END))
return -EINVAL;

- data.set_mask = set_mask;
- data.clear_mask = clear_mask;
-
- ret = apply_to_page_range(&init_mm, start, size, change_page_range,
- &data);
-
- flush_tlb_kernel_range(start, end);
- return ret;
+ return __change_memory_common(start, size, set_mask, clear_mask);
}

int set_memory_ro(unsigned long addr, int numpages)
@@ -87,3 +97,15 @@ int set_memory_x(unsigned long addr, int numpages)
__pgprot(0),
__pgprot(L_PTE_XN));
}
+
+int set_memory_valid(unsigned long addr, int numpages, int enable)
+{
+ if (enable)
+ return __change_memory_common(addr, PAGE_SIZE * numpages,
+ __pgprot(L_PTE_VALID),
+ __pgprot(0));
+ else
+ return __change_memory_common(addr, PAGE_SIZE * numpages,
+ __pgprot(0),
+ __pgprot(L_PTE_VALID));
+}
--
2.26.2