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uprobes/x86: Introduce push_ret_address() 

Extract the "push return address" code from branch_emulate_op() into
the new simple helper, push_ret_address(). It will have more users.

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
This commit is contained in:
Oleg Nesterov 2014-04-24 19:21:38 +02:00
parent 78d9af4cd3
commit 2b82cadffc
1 changed files with 12 additions and 3 deletions
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15
arch/x86/kernel/uprobes.c
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@ -407,6 +407,17 @@ static int default_pre_xol_op(struct arch_uprobe *auprobe, struct pt_regs *regs)
return 0; return 0;
} }
static int push_ret_address(struct pt_regs *regs, unsigned long ip)
{
unsigned long new_sp = regs->sp - sizeof_long();
if (copy_to_user((void __user *)new_sp, &ip, sizeof_long()))
return -EFAULT;
regs->sp = new_sp;
return 0;
}
/* /*
* Adjust the return address pushed by a call insn executed out of line. * Adjust the return address pushed by a call insn executed out of line.
*/ */
@ -517,7 +528,6 @@ static bool branch_emulate_op(struct arch_uprobe *auprobe, struct pt_regs *regs)
unsigned long offs = (long)auprobe->branch.offs; unsigned long offs = (long)auprobe->branch.offs;
if (branch_is_call(auprobe)) { if (branch_is_call(auprobe)) {
unsigned long new_sp = regs->sp - sizeof_long();
/* /*
* If it fails we execute this (mangled, see the comment in * If it fails we execute this (mangled, see the comment in
* branch_clear_offset) insn out-of-line. In the likely case * branch_clear_offset) insn out-of-line. In the likely case
@ -527,9 +537,8 @@ static bool branch_emulate_op(struct arch_uprobe *auprobe, struct pt_regs *regs)
* *
* But there is corner case, see the comment in ->post_xol(). * But there is corner case, see the comment in ->post_xol().
*/ */
if (copy_to_user((void __user *)new_sp, &new_ip, sizeof_long())) if (push_ret_address(regs, new_ip))
return false; return false;
regs->sp = new_sp;
} else if (!check_jmp_cond(auprobe, regs)) { } else if (!check_jmp_cond(auprobe, regs)) {
offs = 0; offs = 0;
} }