[PATCH x86/mm 5/6] x86-32 ptrace get/putreg current task

Roland McGrath
2007-11-29T00:42:22Z

This generalizes the getreg and putreg functions so they can be used on the
current task, as well as on a task stopped in TASK_TRACED and switched off.
This lays the groundwork to share this code for all kinds of user-mode
machine state access, not just ptrace.

Signed-off-by: Roland McGrath <roland@redhat.com>
---
arch/x86/kernel/ptrace_32.c | 8 ++++++++
1 files changed, 8 insertions(+), 0 deletions(-)

diff --git a/arch/x86/kernel/ptrace_32.c b/arch/x86/kernel/ptrace_32.c
index 5aca84e..2607130 100644
--- a/arch/x86/kernel/ptrace_32.c
+++ b/arch/x86/kernel/ptrace_32.c
@@ -55,6 +55,12 @@ static int putreg(struct task_struct *child,
if (value && (value & 3) != 3)
return -EIO;
child->thread.gs = value;
+ if (child == current)
+ /*
+ * The user-mode %gs is not affected by
+ * kernel entry, so we must update the CPU.
+ */
+ loadsegment(gs, value);
return 0;
case DS:
case ES:
@@ -104,6 +110,8 @@ static unsigned long getreg(struct task_struct *child, unsigned long regno)
break;
case GS:
retval = child->thread.gs;
+ if (child == current)
+ savesegment(gs, retval);
break;