diff options
| author | Oleg Nesterov <oleg@redhat.com> | 2014-04-25 18:06:19 +0200 |
|---|---|---|
| committer | Oleg Nesterov <oleg@redhat.com> | 2014-04-30 19:10:39 +0200 |
| commit | 1dc76e6eacef271230d9ff6fd0f91824bda03f44 (patch) | |
| tree | 2e8bcef731ebe89c98964646a6751a84fc5a0906 | |
| parent | 2b82cadffc4154a25c25d88a63c7fb3397cda9d6 (diff) | |
uprobes/x86: Kill adjust_ret_addr(), simplify UPROBE_FIX_CALL logic
The only insn which could have both UPROBE_FIX_IP and UPROBE_FIX_CALL
was 0xe8 "call relative", and now it is handled by branch_xol_ops.
So we can change default_post_xol_op(UPROBE_FIX_CALL) to simply push
the address of next insn == utask->vaddr + insn.length, just we need
to record insn.length into the new auprobe->def.ilen member.
Note: if/when we teach branch_xol_ops to support jcxz/loopz we can
remove the "correction" logic, UPROBE_FIX_IP can use the same address.
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
| -rw-r--r-- | arch/x86/include/asm/uprobes.h | 1 | ||||
| -rw-r--r-- | arch/x86/kernel/uprobes.c | 24 |
2 files changed, 4 insertions, 21 deletions
diff --git a/arch/x86/include/asm/uprobes.h b/arch/x86/include/asm/uprobes.h index 9ce25ce04fe..a040d493a4f 100644 --- a/arch/x86/include/asm/uprobes.h +++ b/arch/x86/include/asm/uprobes.h @@ -54,6 +54,7 @@ struct arch_uprobe { long riprel_target; #endif u8 fixups; + u8 ilen; } def; }; }; diff --git a/arch/x86/kernel/uprobes.c b/arch/x86/kernel/uprobes.c index df75913acfc..5bcce852628 100644 --- a/arch/x86/kernel/uprobes.c +++ b/arch/x86/kernel/uprobes.c @@ -418,24 +418,6 @@ static int push_ret_address(struct pt_regs *regs, unsigned long ip) return 0; } -/* - * Adjust the return address pushed by a call insn executed out of line. - */ -static int adjust_ret_addr(unsigned long sp, long correction) -{ - int rasize = sizeof_long(); - long ra; - - if (copy_from_user(&ra, (void __user *)sp, rasize)) - return -EFAULT; - - ra += correction; - if (copy_to_user((void __user *)sp, &ra, rasize)) - return -EFAULT; - - return 0; -} - static int default_post_xol_op(struct arch_uprobe *auprobe, struct pt_regs *regs) { struct uprobe_task *utask = current->utask; @@ -446,10 +428,9 @@ static int default_post_xol_op(struct arch_uprobe *auprobe, struct pt_regs *regs regs->ip += correction; if (auprobe->def.fixups & UPROBE_FIX_CALL) { - if (adjust_ret_addr(regs->sp, correction)) { - regs->sp += sizeof_long(); + regs->sp += sizeof_long(); + if (push_ret_address(regs, utask->vaddr + auprobe->def.ilen)) return -ERESTART; - } } /* popf; tell the caller to not touch TF */ if (auprobe->def.fixups & UPROBE_FIX_SETF) @@ -687,6 +668,7 @@ int arch_uprobe_analyze_insn(struct arch_uprobe *auprobe, struct mm_struct *mm, handle_riprel_insn(auprobe, &insn); } + auprobe->def.ilen = insn.length; if (fix_ip) auprobe->def.fixups |= UPROBE_FIX_IP; if (fix_call) |