Merge "[REFACTOR] Buffer: move getting next queue element into separate function"

[kernel/swap-modules.git] / uprobe / arch / asm-x86 / swap_uprobes.c

diff --git a/uprobe/arch/asm-x86/swap_uprobes.c b/uprobe/arch/asm-x86/swap_uprobes.c
index 7a5015d..2ec59ac 100644 (file)
--- a/uprobe/arch/asm-x86/swap_uprobes.c
+++ b/uprobe/arch/asm-x86/swap_uprobes.c
@@ -35,6 +35,12 @@ struct uprobe_ctlblk {
         struct kprobe *p;
 };
 
+static unsigned long trampoline_addr(struct uprobe *up)
+{
+       return (unsigned long)(up->kp.ainsn.insn +
+                              UPROBES_TRAMP_RET_BREAK_IDX);
+}
+
 static DEFINE_PER_CPU(struct uprobe_ctlblk, ucb) = { 0, NULL };
 
 static struct kprobe *get_current_probe(void)
@@ -69,10 +75,16 @@ int arch_prepare_uprobe(struct uprobe *up)
        struct kprobe *p = up2kp(up);
        struct task_struct *task = up->task;
        u8 *tramp = up->atramp.tramp;
+       enum { call_relative_opcode = 0xe8 };
 
        if (!read_proc_vm_atomic(task, (unsigned long)p->addr,
                                 tramp, MAX_INSN_SIZE))
                panic("failed to read memory %p!\n", p->addr);
+       /* TODO: this is a workaround */
+       if (tramp[0] == call_relative_opcode) {
+               printk("cannot install probe: 1st instruction is call\n");
+               return -1;
+       }
 
        tramp[UPROBES_TRAMP_RET_BREAK_IDX] = BREAKPOINT_INSTRUCTION;
 
@@ -116,7 +128,8 @@ int setjmp_upre_handler(struct kprobe *p, struct pt_regs *regs)
 void arch_prepare_uretprobe(struct uretprobe_instance *ri, struct pt_regs *regs)
 {
        /* Replace the return addr with trampoline addr */
-       unsigned long ra = (unsigned long)(ri->rp->up.kp.ainsn.insn + UPROBES_TRAMP_RET_BREAK_IDX);
+       unsigned long ra = trampoline_addr(&ri->rp->up);
+       ri->sp = (kprobe_opcode_t *)regs->sp;
 
        if (!read_proc_vm_atomic(current, regs->EREG(sp), &(ri->ret_addr), sizeof(ri->ret_addr)))
                panic("failed to read user space func ra %lx!\n", regs->EREG(sp));
@@ -125,9 +138,41 @@ void arch_prepare_uretprobe(struct uretprobe_instance *ri, struct pt_regs *regs)
                panic("failed to write user space func ra %lx!\n", regs->EREG(sp));
 }
 
+int arch_disarm_urp_inst(struct uretprobe_instance *ri,
+                        struct task_struct *task)
+{
+       int len;
+       unsigned long ret_addr;
+       unsigned long sp = (unsigned long)ri->sp;
+       unsigned long tramp_addr = trampoline_addr(&ri->rp->up);
+       len = read_proc_vm_atomic(task, sp, &ret_addr, sizeof(ret_addr));
+       if (len != sizeof(ret_addr)) {
+               printk("---> %s (%d/%d): failed to read stack from %08lx\n",
+                      task->comm, task->tgid, task->pid, sp);
+               return -EFAULT;
+       }
+
+       if (tramp_addr == ret_addr) {
+               len = write_proc_vm_atomic(task, sp, &ri->ret_addr,
+                                          sizeof(ri->ret_addr));
+               if (len != sizeof(ri->ret_addr)) {
+                       printk("---> %s (%d/%d): failed to write "
+                              "orig_ret_addr to %08lx",
+                              task->comm, task->tgid, task->pid, sp);
+                       return -EFAULT;
+               }
+       } else {
+               printk("---> %s (%d/%d): trampoline NOT found at sp = %08lx\n",
+                      task->comm, task->tgid, task->pid, sp);
+               return -ENOENT;
+       }
+
+       return 0;
+}
+
 unsigned long arch_get_trampoline_addr(struct kprobe *p, struct pt_regs *regs)
 {
-       return (unsigned long)(p->ainsn.insn + UPROBES_TRAMP_RET_BREAK_IDX);
+       return trampoline_addr(kp2up(p));
 }
 
 void arch_set_orig_ret_addr(unsigned long orig_ret_addr, struct pt_regs *regs)
@@ -330,7 +375,7 @@ static int uprobe_exceptions_notify(struct notifier_block *self, unsigned long v
        struct die_args *args = (struct die_args *)data;
        int ret = NOTIFY_DONE;
 
-       if (args->regs && !user_mode_vm(args->regs))
+       if (args->regs == NULL || !user_mode_vm(args->regs))
                return ret;
 
        switch (val) {