diff options
| author | Stephane Eranian <eranian@hpl.hp.com> | 2006-09-26 10:52:28 +0200 |
|---|---|---|
| committer | Andi Kleen <andi@basil.nowhere.org> | 2006-09-26 10:52:28 +0200 |
| commit | d3a4f48d4866b8623ca9adde8ce4e5fde979c132 (patch) | |
| tree | 04413a1f18c6f49688d6008b583b20a287920a0f /arch/x86_64/kernel/ptrace.c | |
| parent | 2f766d16062d0147edff91be15de4a950667ca42 (diff) | |
[PATCH] x86-64 TIF flags for debug regs and io bitmap in ctxsw
Hello,
Following my discussion with Andi. Here is a patch that introduces
two new TIF flags to simplify the context switch code in __switch_to().
The idea is to minimize the number of cache lines accessed in the common
case, i.e., when neither the debug registers nor the I/O bitmap are used.
This patch covers the x86-64 modifications. A patch for i386 follows.
Changelog:
- add TIF_DEBUG to track when debug registers are active
- add TIF_IO_BITMAP to track when I/O bitmap is used
- modify __switch_to() to use the new TIF flags
<signed-off-by>: eranian@hpl.hp.com
Signed-off-by: Andi Kleen <ak@suse.de>
Diffstat (limited to 'arch/x86_64/kernel/ptrace.c')
| -rw-r--r-- | arch/x86_64/kernel/ptrace.c | 8 |
1 files changed, 6 insertions, 2 deletions
diff --git a/arch/x86_64/kernel/ptrace.c b/arch/x86_64/kernel/ptrace.c index 2d50024c9f3..d35ec1bc696 100644 --- a/arch/x86_64/kernel/ptrace.c +++ b/arch/x86_64/kernel/ptrace.c @@ -420,9 +420,13 @@ long arch_ptrace(struct task_struct *child, long request, long addr, long data) if ((0x5554 >> ((data >> (16 + 4*i)) & 0xf)) & 1) break; if (i == 4) { - child->thread.debugreg7 = data; + child->thread.debugreg7 = data; + if (data) + set_tsk_thread_flag(child, TIF_DEBUG); + else + clear_tsk_thread_flag(child, TIF_DEBUG); ret = 0; - } + } break; } break; |