[FIX] using functions set_memory_[ro\rw]()

because those functions may be not exported

Change-Id: I07c8917eb2c326d0a04a8f2007829e0dd77d20f4
Signed-off-by: Vyacheslav Cherkashin <v.cherkashin@samsung.com>

3 files changed, 50 insertions, 13 deletions

diff --git a/kprobe/arch/asm-arm/memory_rwx.c b/kprobe/arch/asm-arm/memory_rwx.c
index d120872c..bb751a66 100644
--- a/kprobe/arch/asm-arm/memory_rwx.c
+++ b/kprobe/arch/asm-arm/memory_rwx.c
@@ -31,15 +31,10 @@
 #include <ksyms/ksyms.h>
 
 
-static unsigned long get_init_mm(void)
-{
-	static unsigned long addr = 0;
-
-	if (addr == 0)
-		addr = swap_ksyms("init_mm");
+static struct mm_struct *swap_init_mm = NULL;
+static int (*swap_set_memory_ro)(unsigned long addr, int numpages) = NULL;
+static int (*swap_set_memory_rw)(unsigned long addr, int numpages) = NULL;
 
-	return addr;
-}
 
 static int get_pte_cb(pte_t *ptep, pgtable_t token,
 		      unsigned long addr, void *data)
@@ -51,10 +46,10 @@ static int get_pte_cb(pte_t *ptep, pgtable_t token,
 
 static pte_t get_pte(unsigned long page_addr)
 {
-	struct mm_struct *mm = (struct mm_struct *)get_init_mm();
 	pte_t pte = 0;
 
-	apply_to_page_range(mm, page_addr, PAGE_SIZE, get_pte_cb, &pte);
+	apply_to_page_range(swap_init_mm, page_addr,
+			    PAGE_SIZE, get_pte_cb, &pte);
 
 	return pte;
 }
@@ -71,9 +66,13 @@ static void write_to_module(unsigned long addr, unsigned long val)
 		DEFINE_SPINLOCK(mem_lock);
 
 		spin_lock_irqsave(&mem_lock, flags);
-		set_memory_rw(page_addr, 1);
-		*maddr = val;
-		set_memory_ro(page_addr, 1);
+		if (swap_set_memory_rw(page_addr, 1) == 0) {
+			*maddr = val;
+			swap_set_memory_ro(page_addr, 1);
+		} else {
+			printk("RWX: failed to write memory %08lx (%08lx)\n",
+			       addr, val);
+		}
 		spin_unlock_irqrestore(&mem_lock, flags);
 	} else {
 		*maddr = val;
@@ -94,3 +93,29 @@ void mem_rwx_write_u32(unsigned long addr, unsigned long val)
 		write_to_module(addr, val);
 	}
 }
+
+int mem_rwx_init(void)
+{
+	const char *sym;
+
+	sym = "set_memory_ro";
+	swap_set_memory_ro = (void *)swap_ksyms(sym);
+	if (swap_set_memory_ro == NULL)
+		goto not_found;
+
+	sym = "set_memory_rw";
+	swap_set_memory_rw = (void *)swap_ksyms(sym);
+	if (swap_set_memory_rw == NULL)
+		goto not_found;
+
+	sym = "init_mm";
+	swap_init_mm = (void *)swap_ksyms(sym);
+	if (swap_init_mm == NULL)
+		goto not_found;
+
+	return 0;
+
+not_found:
+	printk("ERROR: symbol '%s' not found\n", sym);
+	return -ESRCH;
+}
diff --git a/kprobe/arch/asm-arm/memory_rwx.h b/kprobe/arch/asm-arm/memory_rwx.h
index a083a3b2..97879bba 100644
--- a/kprobe/arch/asm-arm/memory_rwx.h
+++ b/kprobe/arch/asm-arm/memory_rwx.h
@@ -29,6 +29,8 @@
 #define _MEMORY_RWX_H
 
 
+int mem_rwx_init(void);
+void mem_rwx_exit(void) {};
 void mem_rwx_write_u32(unsigned long addr, unsigned long val);
 
 
diff --git a/kprobe/arch/asm-arm/swap_kprobes.c b/kprobe/arch/asm-arm/swap_kprobes.c
index 396bd146..e0b989b1 100644
--- a/kprobe/arch/asm-arm/swap_kprobes.c
+++ b/kprobe/arch/asm-arm/swap_kprobes.c
@@ -870,6 +870,12 @@ int swap_arch_init_kprobes(void)
 {
 	int ret;
 
+#ifdef CONFIG_STRICT_MEMORY_RWX
+	ret = mem_rwx_init();
+	if (ret)
+		return ret;
+#endif /* CONFIG_STRICT_MEMORY_RWX */
+
 	// Register hooks (kprobe_handler)
 	__swap_register_undef_hook = (void *)swap_ksyms("register_undef_hook");
 	if (__swap_register_undef_hook == NULL) {
@@ -904,6 +910,10 @@ void swap_arch_exit_kprobes(void)
 {
 	kjump_exit();
 	swap_unregister_undef_hook(&undef_ho_k);
+
+#ifdef CONFIG_STRICT_MEMORY_RWX
+	mem_rwx_exit();
+#endif /* CONFIG_STRICT_MEMORY_RWX */
 }
 
 /* export symbol for trampoline_arm.h */