summaryrefslogtreecommitdiff
path: root/arch/x86/kernel/step.c
diff options
context:
space:
mode:
authorPeter Zijlstra <a.p.zijlstra@chello.nl>2010-03-25 14:51:50 +0100
committerIngo Molnar <mingo@elte.hu>2010-03-26 11:33:55 +0100
commitfaa4602e47690fb11221e00f9b9697c8dc0d4b19 (patch)
treeaf667d1cdff7dc63b6893ee3f27a1f2503229ed1 /arch/x86/kernel/step.c
parent7c5ecaf7666617889f337296c610815b519abfa9 (diff)
x86, perf, bts, mm: Delete the never used BTS-ptrace code
Support for the PMU's BTS features has been upstreamed in v2.6.32, but we still have the old and disabled ptrace-BTS, as Linus noticed it not so long ago. It's buggy: TIF_DEBUGCTLMSR is trampling all over that MSR without regard for other uses (perf) and doesn't provide the flexibility needed for perf either. Its users are ptrace-block-step and ptrace-bts, since ptrace-bts was never used and ptrace-block-step can be implemented using a much simpler approach. So axe all 3000 lines of it. That includes the *locked_memory*() APIs in mm/mlock.c as well. Reported-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Roland McGrath <roland@redhat.com> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Markus Metzger <markus.t.metzger@intel.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Andrew Morton <akpm@linux-foundation.org> LKML-Reference: <20100325135413.938004390@chello.nl> Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'arch/x86/kernel/step.c')
-rw-r--r--arch/x86/kernel/step.c36
1 files changed, 4 insertions, 32 deletions
diff --git a/arch/x86/kernel/step.c b/arch/x86/kernel/step.c
index 3149032ff107..7beba0769a8c 100644
--- a/arch/x86/kernel/step.c
+++ b/arch/x86/kernel/step.c
@@ -158,22 +158,6 @@ static int enable_single_step(struct task_struct *child)
}
/*
- * Install this value in MSR_IA32_DEBUGCTLMSR whenever child is running.
- */
-static void write_debugctlmsr(struct task_struct *child, unsigned long val)
-{
- if (child->thread.debugctlmsr == val)
- return;
-
- child->thread.debugctlmsr = val;
-
- if (child != current)
- return;
-
- update_debugctlmsr(val);
-}
-
-/*
* Enable single or block step.
*/
static void enable_step(struct task_struct *child, bool block)
@@ -185,17 +169,9 @@ static void enable_step(struct task_struct *child, bool block)
* So noone should try to use debugger block stepping in a program
* that uses user-mode single stepping itself.
*/
- if (enable_single_step(child) && block) {
- set_tsk_thread_flag(child, TIF_DEBUGCTLMSR);
- write_debugctlmsr(child,
- child->thread.debugctlmsr | DEBUGCTLMSR_BTF);
- } else {
- write_debugctlmsr(child,
- child->thread.debugctlmsr & ~DEBUGCTLMSR_BTF);
-
- if (!child->thread.debugctlmsr)
- clear_tsk_thread_flag(child, TIF_DEBUGCTLMSR);
- }
+ if (!enable_single_step(child))
+ return;
+ /* XXX */
}
void user_enable_single_step(struct task_struct *child)
@@ -213,11 +189,7 @@ void user_disable_single_step(struct task_struct *child)
/*
* Make sure block stepping (BTF) is disabled.
*/
- write_debugctlmsr(child,
- child->thread.debugctlmsr & ~DEBUGCTLMSR_BTF);
-
- if (!child->thread.debugctlmsr)
- clear_tsk_thread_flag(child, TIF_DEBUGCTLMSR);
+ /* XXX */
/* Always clear TIF_SINGLESTEP... */
clear_tsk_thread_flag(child, TIF_SINGLESTEP);