[IMPROVE] x86: create jumper

Change-Id: Ic356826985c26b7397ab19b5996ba4a78fc54208
Signed-off-by: Vyacheslav Cherkashin <v.cherkashin@samsung.com>

diff --git a/kprobe/arch/asm-x86/swap_kprobes.c b/kprobe/arch/asm-x86/swap_kprobes.c
index cd96cf2..f9cf8f6 100644 (file)
--- a/kprobe/arch/asm-x86/swap_kprobes.c
+++ b/kprobe/arch/asm-x86/swap_kprobes.c
@@ -1000,6 +1000,89 @@ static void kjump_exit(void)
 
 
 
+/*
+ ******************************************************************************
+ *                                   jumper                                   *
+ ******************************************************************************
+ */
+struct cb_data {
+       unsigned long ret_addr;
+       unsigned long bx;
+
+       jumper_cb_t cb;
+       char data[0];
+};
+
+static unsigned long __used get_bx(struct cb_data *data)
+{
+       return data->bx;
+}
+
+static unsigned long __used jump_handler(struct cb_data *data)
+{
+       unsigned long ret_addr = data->ret_addr;
+
+       /* call callback */
+       data->cb(data->data);
+
+       /* FIXME: potential memory leak, when process kill */
+       kfree(data);
+
+       return ret_addr;
+}
+
+void jump_trampoline(void);
+__asm(
+       "jump_trampoline:               \n"
+       "pushf                          \n"
+       SWAP_SAVE_REGS_STRING
+       "movl   %ebx, %eax              \n"     /* data --> ax */
+       "call   get_bx                  \n"
+       "movl   %eax, (%esp)            \n"     /* restore bx */
+       "movl   %ebx, %eax              \n"     /* data --> ax */
+       "call   jump_handler            \n"
+       /* move flags to cs */
+       "movl 56(%esp), %edx            \n"
+       "movl %edx, 52(%esp)            \n"
+       /* replace saved flags with true return address. */
+       "movl %eax, 56(%esp)            \n"
+       SWAP_RESTORE_REGS_STRING
+       "popf\n"
+       "ret\n"
+);
+
+unsigned long get_jump_addr(void)
+{
+       return (unsigned long)&jump_trampoline;
+}
+EXPORT_SYMBOL_GPL(get_jump_addr);
+
+int set_jump_cb(unsigned long ret_addr, struct pt_regs *regs,
+               jumper_cb_t cb, void *data, size_t size)
+{
+       struct cb_data *cb_data;
+
+       cb_data = kmalloc(sizeof(*cb_data) + size, GFP_ATOMIC);
+       if (cb_data == NULL)
+               return -ENOMEM;
+
+       /* save data */
+       cb_data->ret_addr = ret_addr;
+       cb_data->cb = cb;
+       cb_data->bx = regs->bx;
+       memcpy(cb_data->data, data, size);
+
+       /* save cb_data to bx */
+       regs->bx = (long)cb_data;
+
+       return 0;
+}
+EXPORT_SYMBOL_GPL(set_jump_cb);
+
+
+
+
+
 /**
  * @brief Initializes x86 module deps.
  *

diff --git a/kprobe/arch/asm-x86/swap_kprobes.h b/kprobe/arch/asm-x86/swap_kprobes.h
index e8e7e77..ce6e7a1 100644 (file)
--- a/kprobe/arch/asm-x86/swap_kprobes.h
+++ b/kprobe/arch/asm-x86/swap_kprobes.h
@@ -266,6 +266,10 @@ typedef unsigned long (*jumper_cb_t)(void *);
 int set_kjump_cb(struct pt_regs *regs, jumper_cb_t cb,
                 void *data, size_t size);
 
+unsigned long get_jump_addr(void);
+int set_jump_cb(unsigned long ret_addr, struct pt_regs *regs,
+               jumper_cb_t cb, void *data, size_t size);
+
 int swap_arch_init_kprobes(void);
 void swap_arch_exit_kprobes(void);