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authorMarkus Metzger <markus.t.metzger@intel.com>2008-12-19 15:10:24 +0100
committerIngo Molnar <mingo@elte.hu>2008-12-20 09:15:46 +0100
commitbf53de907dfdaac178c92d774aae7370d7b97d20 (patch)
tree738a07a8b4b22f7bb8ec2029c9ea9c635db6c62a /arch/x86/kernel
parent30cd324e9787ccc9a5ede59742d5409857550692 (diff)
x86, bts: add fork and exit handling
Impact: introduce new ptrace facility Add arch_ptrace_untrace() function that is called when the tracer detaches (either voluntarily or when the tracing task dies); ptrace_disable() is only called on a voluntary detach. Add ptrace_fork() and arch_ptrace_fork(). They are called when a traced task is forked. Clear DS and BTS related fields on fork. Release DS resources and reclaim memory in ptrace_untrace(). This releases resources already when the tracing task dies. We used to do that when the traced task dies. Signed-off-by: Markus Metzger <markus.t.metzger@intel.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'arch/x86/kernel')
-rw-r--r--arch/x86/kernel/ds.c11
-rw-r--r--arch/x86/kernel/process_32.c20
-rw-r--r--arch/x86/kernel/process_64.c20
-rw-r--r--arch/x86/kernel/ptrace.c50
4 files changed, 69 insertions, 32 deletions
diff --git a/arch/x86/kernel/ds.c b/arch/x86/kernel/ds.c
index 98d271e60e0..da91701a234 100644
--- a/arch/x86/kernel/ds.c
+++ b/arch/x86/kernel/ds.c
@@ -1017,3 +1017,14 @@ void ds_switch_to(struct task_struct *prev, struct task_struct *next)
update_debugctlmsr(next->thread.debugctlmsr);
}
+
+void ds_copy_thread(struct task_struct *tsk, struct task_struct *father)
+{
+ clear_tsk_thread_flag(tsk, TIF_DS_AREA_MSR);
+ tsk->thread.ds_ctx = NULL;
+}
+
+void ds_exit_thread(struct task_struct *tsk)
+{
+ WARN_ON(tsk->thread.ds_ctx);
+}
diff --git a/arch/x86/kernel/process_32.c b/arch/x86/kernel/process_32.c
index 605eff9a8ac..3ba155d2488 100644
--- a/arch/x86/kernel/process_32.c
+++ b/arch/x86/kernel/process_32.c
@@ -60,6 +60,7 @@
#include <asm/idle.h>
#include <asm/syscalls.h>
#include <asm/smp.h>
+#include <asm/ds.h>
asmlinkage void ret_from_fork(void) __asm__("ret_from_fork");
@@ -251,17 +252,8 @@ void exit_thread(void)
tss->x86_tss.io_bitmap_base = INVALID_IO_BITMAP_OFFSET;
put_cpu();
}
-#ifdef CONFIG_X86_DS
- /* Free any BTS tracers that have not been properly released. */
- if (unlikely(current->bts)) {
- ds_release_bts(current->bts);
- current->bts = NULL;
-
- kfree(current->bts_buffer);
- current->bts_buffer = NULL;
- current->bts_size = 0;
- }
-#endif /* CONFIG_X86_DS */
+
+ ds_exit_thread(current);
}
void flush_thread(void)
@@ -343,6 +335,12 @@ int copy_thread(int nr, unsigned long clone_flags, unsigned long sp,
kfree(p->thread.io_bitmap_ptr);
p->thread.io_bitmap_max = 0;
}
+
+ ds_copy_thread(p, current);
+
+ clear_tsk_thread_flag(p, TIF_DEBUGCTLMSR);
+ p->thread.debugctlmsr = 0;
+
return err;
}
diff --git a/arch/x86/kernel/process_64.c b/arch/x86/kernel/process_64.c
index 1cfd2a4bf85..416fb9282f4 100644
--- a/arch/x86/kernel/process_64.c
+++ b/arch/x86/kernel/process_64.c
@@ -53,6 +53,7 @@
#include <asm/ia32.h>
#include <asm/idle.h>
#include <asm/syscalls.h>
+#include <asm/ds.h>
asmlinkage extern void ret_from_fork(void);
@@ -236,17 +237,8 @@ void exit_thread(void)
t->io_bitmap_max = 0;
put_cpu();
}
-#ifdef CONFIG_X86_DS
- /* Free any BTS tracers that have not been properly released. */
- if (unlikely(current->bts)) {
- ds_release_bts(current->bts);
- current->bts = NULL;
-
- kfree(current->bts_buffer);
- current->bts_buffer = NULL;
- current->bts_size = 0;
- }
-#endif /* CONFIG_X86_DS */
+
+ ds_exit_thread(current);
}
void flush_thread(void)
@@ -376,6 +368,12 @@ int copy_thread(int nr, unsigned long clone_flags, unsigned long sp,
if (err)
goto out;
}
+
+ ds_copy_thread(p, me);
+
+ clear_tsk_thread_flag(p, TIF_DEBUGCTLMSR);
+ p->thread.debugctlmsr = 0;
+
err = 0;
out:
if (err && p->thread.io_bitmap_ptr) {
diff --git a/arch/x86/kernel/ptrace.c b/arch/x86/kernel/ptrace.c
index 45e9855da2d..6ad2bb60765 100644
--- a/arch/x86/kernel/ptrace.c
+++ b/arch/x86/kernel/ptrace.c
@@ -769,8 +769,47 @@ static int ptrace_bts_size(struct task_struct *child)
return (trace->ds.top - trace->ds.begin) / trace->ds.size;
}
+
+static void ptrace_bts_fork(struct task_struct *tsk)
+{
+ tsk->bts = NULL;
+ tsk->bts_buffer = NULL;
+ tsk->bts_size = 0;
+ tsk->thread.bts_ovfl_signal = 0;
+}
+
+static void ptrace_bts_untrace(struct task_struct *child)
+{
+ if (unlikely(child->bts)) {
+ ds_release_bts(child->bts);
+ child->bts = NULL;
+
+ kfree(child->bts_buffer);
+ child->bts_buffer = NULL;
+ child->bts_size = 0;
+ }
+}
+
+static void ptrace_bts_detach(struct task_struct *child)
+{
+ ptrace_bts_untrace(child);
+}
+#else
+static inline void ptrace_bts_fork(struct task_struct *tsk) {}
+static inline void ptrace_bts_detach(struct task_struct *child) {}
+static inline void ptrace_bts_untrace(struct task_struct *child) {}
#endif /* CONFIG_X86_PTRACE_BTS */
+void x86_ptrace_fork(struct task_struct *child, unsigned long clone_flags)
+{
+ ptrace_bts_fork(child);
+}
+
+void x86_ptrace_untrace(struct task_struct *child)
+{
+ ptrace_bts_untrace(child);
+}
+
/*
* Called by kernel/ptrace.c when detaching..
*
@@ -782,16 +821,7 @@ void ptrace_disable(struct task_struct *child)
#ifdef TIF_SYSCALL_EMU
clear_tsk_thread_flag(child, TIF_SYSCALL_EMU);
#endif
-#ifdef CONFIG_X86_PTRACE_BTS
- if (child->bts) {
- ds_release_bts(child->bts);
- child->bts = NULL;
-
- kfree(child->bts_buffer);
- child->bts_buffer = NULL;
- child->bts_size = 0;
- }
-#endif /* CONFIG_X86_PTRACE_BTS */
+ ptrace_bts_detach(child);
}
#if defined CONFIG_X86_32 || defined CONFIG_IA32_EMULATION