[RFC 2/3] arm: mm: Define set_memory_* functions for ARM

[Laura Abbott <lauraa@codeaurora.org>]

Other architectures define various set_memory functions to allow
attributes to be changed (e.g. set_memory_x, set_memory_rw, etc.)
Currently, these functions are missing on ARM. Define these in an
appropriate manner for ARM.

Signed-off-by: Laura Abbott <lauraa@codeaurora.org>
---
 arch/arm/include/asm/cacheflush.h |    5 ++
 arch/arm/mm/mmu.c                 |   86 +++++++++++++++++++++++++++++++++++++
 2 files changed, 91 insertions(+), 0 deletions(-)

diff --git a/arch/arm/include/asm/cacheflush.h b/arch/arm/include/asm/cacheflush.h
index bff7138..55ed26b 100644
--- a/arch/arm/include/asm/cacheflush.h
+++ b/arch/arm/include/asm/cacheflush.h
@@ -438,4 +438,9 @@ static inline void __sync_cache_range_r(volatile void *p, size_t size)
 #define sync_cache_w(ptr) __sync_cache_range_w(ptr, sizeof *(ptr))
 #define sync_cache_r(ptr) __sync_cache_range_r(ptr, sizeof *(ptr))
 
+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);
+
 #endif
diff --git a/arch/arm/mm/mmu.c b/arch/arm/mm/mmu.c
index e0d8565..1dc14a3 100644
--- a/arch/arm/mm/mmu.c
+++ b/arch/arm/mm/mmu.c
@@ -335,6 +335,92 @@ const struct mem_type *get_mem_type(unsigned int type)
 }
 EXPORT_SYMBOL(get_mem_type);
 
+static int pte_set_ro(pte_t *ptep, pgtable_t token, unsigned long addr,
+			void *data)
+{
+	pte_t pte = pte_wrprotect(*ptep);
+
+	set_pte_ext(ptep, pte, 0);
+	return 0;
+}
+
+int set_memory_ro(unsigned long addr, int numpages)
+{
+	unsigned long start = addr;
+	unsigned long size = PAGE_SIZE*numpages;
+	unsigned end = start + size;
+
+	apply_to_page_range(&init_mm, start, size, pte_set_ro, NULL);
+	dsb();
+	flush_tlb_kernel_range(start, end);
+	return 0;
+}
+
+static int pte_set_rw(pte_t *ptep, pgtable_t token, unsigned long addr,
+			void *data)
+{
+	pte_t pte = pte_mkwrite(*ptep);
+
+	set_pte_ext(ptep, pte, 0);
+	return 0;
+}
+
+int set_memory_rw(unsigned long addr, int numpages)
+{
+	unsigned long start = addr;
+	unsigned long size = PAGE_SIZE*numpages;
+	unsigned end = start + size;
+
+	apply_to_page_range(&init_mm, start, size, pte_set_rw, NULL);
+	dsb();
+	flush_tlb_kernel_range(start, end);
+	return 0;
+
+}
+
+static int pte_set_x(pte_t *ptep, pgtable_t token, unsigned long addr,
+			void *data)
+{
+	pte_t pte = pte_mkexec(*ptep);
+
+	set_pte_ext(ptep, pte, 0);
+	return 0;
+}
+
+int set_memory_x(unsigned long addr, int numpages)
+{
+	unsigned long start = addr;
+	unsigned long size = PAGE_SIZE*numpages;
+	unsigned end = start + size;
+
+	apply_to_page_range(&init_mm, start, size, pte_set_x, NULL);
+	dsb();
+	flush_tlb_kernel_range(start, end);
+	return 0;
+}
+
+static int pte_set_nx(pte_t *ptep, pgtable_t token, unsigned long addr,
+			void *data)
+{
+	pte_t pte = pte_mknexec(*ptep);
+
+	set_pte_ext(ptep, pte, 0);
+	return 0;
+}
+
+int set_memory_nx(unsigned long addr, int numpages)
+{
+	unsigned long start = addr;
+	unsigned long size = PAGE_SIZE*numpages;
+	unsigned end = start + size;
+
+	apply_to_page_range(&init_mm, start, size, pte_set_nx, NULL);
+	dsb();
+	flush_tlb_kernel_range(start, end);
+
+	return 0;
+}
+
 /*
  * Adjust the PMD section entries according to the CPU in use.
  */
-- 
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