diff options
| author | Oleg Nesterov <oleg@redhat.com> | 2014-04-21 20:39:56 +0200 |
|---|---|---|
| committer | Oleg Nesterov <oleg@redhat.com> | 2014-04-30 19:10:37 +0200 |
| commit | 220ef8dc9a7a63fe202aacd3fc61e5104f6dd98c (patch) | |
| tree | 1176022547d4fd10b216612e0b73440570520015 /arch/x86/kernel/uprobes.c | |
| parent | 6ded5f3848bfd3227ee208aa38f8bf8d7209d4e3 (diff) | |
uprobes/x86: Move UPROBE_FIX_SETF logic from arch_uprobe_post_xol() to default_post_xol_op()
UPROBE_FIX_SETF is only needed to handle "popf" correctly but it is
processed by the generic arch_uprobe_post_xol() code. This doesn't
allows us to make ->fixups private for default_xol_ops.
1 Change default_post_xol_op(UPROBE_FIX_SETF) to set ->saved_tf = T.
"popf" always reads the flags from stack, it doesn't matter if TF
was set or not before single-step. Ignoring the naming, this is
even more logical, "saved_tf" means "owned by application" and we
do not own this flag after "popf".
2. Change arch_uprobe_post_xol() to save ->saved_tf into the local
"bool send_sigtrap" before ->post_xol().
3. Change arch_uprobe_post_xol() to ignore UPROBE_FIX_SETF and just
check ->saved_tf after ->post_xol().
With this patch ->fixups and ->rip_rela_target_address are only used
by default_xol_ops hooks, we are ready to remove them from the common
part of arch_uprobe.
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Reviewed-by: Jim Keniston <jkenisto@us.ibm.com>
Diffstat (limited to 'arch/x86/kernel/uprobes.c')
| -rw-r--r-- | arch/x86/kernel/uprobes.c | 20 |
1 files changed, 12 insertions, 8 deletions
diff --git a/arch/x86/kernel/uprobes.c b/arch/x86/kernel/uprobes.c index 2efb93f96030..b2bca293fc57 100644 --- a/arch/x86/kernel/uprobes.c +++ b/arch/x86/kernel/uprobes.c @@ -441,6 +441,9 @@ static int default_post_xol_op(struct arch_uprobe *auprobe, struct pt_regs *regs return -ERESTART; } } + /* popf; tell the caller to not touch TF */ + if (auprobe->fixups & UPROBE_FIX_SETF) + utask->autask.saved_tf = true; return 0; } @@ -757,15 +760,15 @@ bool arch_uprobe_xol_was_trapped(struct task_struct *t) int arch_uprobe_post_xol(struct arch_uprobe *auprobe, struct pt_regs *regs) { struct uprobe_task *utask = current->utask; + bool send_sigtrap = utask->autask.saved_tf; + int err = 0; WARN_ON_ONCE(current->thread.trap_nr != UPROBE_TRAP_NR); current->thread.trap_nr = utask->autask.saved_trap_nr; if (auprobe->ops->post_xol) { - int err = auprobe->ops->post_xol(auprobe, regs); + err = auprobe->ops->post_xol(auprobe, regs); if (err) { - if (!utask->autask.saved_tf) - regs->flags &= ~X86_EFLAGS_TF; /* * Restore ->ip for restart or post mortem analysis. * ->post_xol() must not return -ERESTART unless this @@ -773,8 +776,8 @@ int arch_uprobe_post_xol(struct arch_uprobe *auprobe, struct pt_regs *regs) */ regs->ip = utask->vaddr; if (err == -ERESTART) - return 0; - return err; + err = 0; + send_sigtrap = false; } } /* @@ -782,12 +785,13 @@ int arch_uprobe_post_xol(struct arch_uprobe *auprobe, struct pt_regs *regs) * so we can get an extra SIGTRAP if we do not clear TF. We need * to examine the opcode to make it right. */ - if (utask->autask.saved_tf) + if (send_sigtrap) send_sig(SIGTRAP, current, 0); - else if (!(auprobe->fixups & UPROBE_FIX_SETF)) + + if (!utask->autask.saved_tf) regs->flags &= ~X86_EFLAGS_TF; - return 0; + return err; } /* callback routine for handling exceptions. */ |