x86, ptrace: new ptrace BTS API
Here's the new ptrace BTS API that supports two different overflow handling mechanisms (wrap-around and buffer-full-signal) to support two different use cases (debugging and profiling). It further combines buffer allocation and configuration. Opens: - memory rlimit - overflow signal What would be the right signal to use? Signed-off-by: Markus Metzger <markus.t.metzger@intel.com> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
This commit is contained in:
Markus Metzger
committed by
Ingo Molnar
Ingo Molnar
parent
e4811f2568
commit
a95d67f87e
@@ -32,12 +32,6 @@
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#include <asm/ds.h>
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/*
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* The maximal size of a BTS buffer per traced task in number of BTS
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* records.
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*/
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#define PTRACE_BTS_BUFFER_MAX 4000
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/*
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* does not yet catch signals sent when the child dies.
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* in exit.c or in signal.c.
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@@ -466,17 +460,12 @@ static int ptrace_set_debugreg(struct task_struct *child,
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return 0;
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}
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static int ptrace_bts_max_buffer_size(void)
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{
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return PTRACE_BTS_BUFFER_MAX;
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}
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static int ptrace_bts_get_buffer_size(struct task_struct *child)
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static int ptrace_bts_get_size(struct task_struct *child)
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{
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if (!child->thread.ds_area_msr)
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return -ENXIO;
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return ds_get_bts_size((void *)child->thread.ds_area_msr);
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return ds_get_bts_index((void *)child->thread.ds_area_msr);
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}
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static int ptrace_bts_read_record(struct task_struct *child,
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@@ -485,7 +474,7 @@ static int ptrace_bts_read_record(struct task_struct *child,
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{
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struct bts_struct ret;
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int retval;
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int bts_size;
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int bts_end;
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int bts_index;
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if (!child->thread.ds_area_msr)
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@@ -494,15 +483,15 @@ static int ptrace_bts_read_record(struct task_struct *child,
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if (index < 0)
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return -EINVAL;
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bts_size = ds_get_bts_size((void *)child->thread.ds_area_msr);
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if (bts_size <= index)
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bts_end = ds_get_bts_end((void *)child->thread.ds_area_msr);
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if (bts_end <= index)
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return -EINVAL;
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/* translate the ptrace bts index into the ds bts index */
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bts_index = ds_get_bts_index((void *)child->thread.ds_area_msr);
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bts_index -= (index + 1);
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if (bts_index < 0)
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bts_index += bts_size;
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bts_index += bts_end;
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retval = ds_read_bts((void *)child->thread.ds_area_msr,
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bts_index, &ret);
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@@ -530,19 +519,97 @@ static int ptrace_bts_write_record(struct task_struct *child,
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return sizeof(*in);
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}
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static int ptrace_bts_config(struct task_struct *child,
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unsigned long options)
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static int ptrace_bts_clear(struct task_struct *child)
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{
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unsigned long debugctl_mask = ds_debugctl_mask();
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int retval;
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retval = ptrace_bts_get_buffer_size(child);
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if (retval < 0)
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return retval;
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if (retval == 0)
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if (!child->thread.ds_area_msr)
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return -ENXIO;
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if (options & PTRACE_BTS_O_TRACE_TASK) {
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return ds_clear((void *)child->thread.ds_area_msr);
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}
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static int ptrace_bts_drain(struct task_struct *child,
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struct bts_struct __user *out)
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{
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int end, i;
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void *ds = (void *)child->thread.ds_area_msr;
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if (!ds)
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return -ENXIO;
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end = ds_get_bts_index(ds);
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if (end <= 0)
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return end;
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for (i = 0; i < end; i++, out++) {
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struct bts_struct ret;
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int retval;
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retval = ds_read_bts(ds, i, &ret);
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if (retval < 0)
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return retval;
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if (copy_to_user(out, &ret, sizeof(ret)))
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return -EFAULT;
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}
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ds_clear(ds);
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return i;
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}
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static int ptrace_bts_config(struct task_struct *child,
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const struct ptrace_bts_config __user *ucfg)
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{
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struct ptrace_bts_config cfg;
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unsigned long debugctl_mask;
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int bts_size, ret;
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void *ds;
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if (copy_from_user(&cfg, ucfg, sizeof(cfg)))
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return -EFAULT;
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bts_size = 0;
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ds = (void *)child->thread.ds_area_msr;
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if (ds) {
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bts_size = ds_get_bts_size(ds);
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if (bts_size < 0)
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return bts_size;
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}
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if (bts_size != cfg.size) {
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ret = ds_free((void **)&child->thread.ds_area_msr);
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if (ret < 0)
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return ret;
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if (cfg.size > 0)
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ret = ds_allocate((void **)&child->thread.ds_area_msr,
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cfg.size);
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ds = (void *)child->thread.ds_area_msr;
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if (ds)
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set_tsk_thread_flag(child, TIF_DS_AREA_MSR);
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else
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clear_tsk_thread_flag(child, TIF_DS_AREA_MSR);
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if (ret < 0)
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return ret;
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bts_size = ds_get_bts_size(ds);
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if (bts_size <= 0)
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return bts_size;
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}
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if (ds) {
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if (cfg.flags & PTRACE_BTS_O_SIGNAL) {
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ret = ds_set_overflow(ds, DS_O_SIGNAL);
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} else {
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ret = ds_set_overflow(ds, DS_O_WRAP);
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}
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if (ret < 0)
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return ret;
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}
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debugctl_mask = ds_debugctl_mask();
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if (ds && (cfg.flags & PTRACE_BTS_O_TRACE)) {
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child->thread.debugctlmsr |= debugctl_mask;
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set_tsk_thread_flag(child, TIF_DEBUGCTLMSR);
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} else {
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@@ -555,7 +622,7 @@ static int ptrace_bts_config(struct task_struct *child,
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clear_tsk_thread_flag(child, TIF_DEBUGCTLMSR);
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}
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if (options & PTRACE_BTS_O_TIMESTAMPS)
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if (ds && (cfg.flags & PTRACE_BTS_O_SCHED))
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set_tsk_thread_flag(child, TIF_BTS_TRACE_TS);
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else
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clear_tsk_thread_flag(child, TIF_BTS_TRACE_TS);
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@@ -563,59 +630,32 @@ static int ptrace_bts_config(struct task_struct *child,
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return 0;
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}
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static int ptrace_bts_status(struct task_struct *child)
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static int ptrace_bts_status(struct task_struct *child,
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struct ptrace_bts_config __user *ucfg)
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{
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unsigned long debugctl_mask = ds_debugctl_mask();
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int retval, status = 0;
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void *ds = (void *)child->thread.ds_area_msr;
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struct ptrace_bts_config cfg;
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retval = ptrace_bts_get_buffer_size(child);
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if (retval < 0)
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return retval;
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if (retval == 0)
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return -ENXIO;
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memset(&cfg, 0, sizeof(cfg));
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if (ptrace_bts_get_buffer_size(child) <= 0)
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return -ENXIO;
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if (ds) {
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cfg.size = ds_get_bts_size(ds);
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if (test_tsk_thread_flag(child, TIF_DEBUGCTLMSR) &&
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child->thread.debugctlmsr & debugctl_mask)
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status |= PTRACE_BTS_O_TRACE_TASK;
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if (test_tsk_thread_flag(child, TIF_BTS_TRACE_TS))
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status |= PTRACE_BTS_O_TIMESTAMPS;
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if (ds_get_overflow(ds) == DS_O_SIGNAL)
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cfg.flags |= PTRACE_BTS_O_SIGNAL;
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return status;
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}
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if (test_tsk_thread_flag(child, TIF_DEBUGCTLMSR) &&
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child->thread.debugctlmsr & ds_debugctl_mask())
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cfg.flags |= PTRACE_BTS_O_TRACE;
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static int ptrace_bts_allocate_bts(struct task_struct *child,
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int size_in_records)
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{
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int retval = 0;
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void *ds;
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if (size_in_records < 0)
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return -EINVAL;
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if (size_in_records > ptrace_bts_max_buffer_size())
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return -EINVAL;
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if (size_in_records == 0) {
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ptrace_bts_config(child, /* options = */ 0);
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} else {
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retval = ds_allocate(&ds, size_in_records);
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if (retval)
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return retval;
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if (test_tsk_thread_flag(child, TIF_BTS_TRACE_TS))
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cfg.flags |= PTRACE_BTS_O_SCHED;
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}
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if (child->thread.ds_area_msr)
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ds_free((void **)&child->thread.ds_area_msr);
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if (copy_to_user(ucfg, &cfg, sizeof(cfg)))
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return -EFAULT;
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child->thread.ds_area_msr = (unsigned long)ds;
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if (child->thread.ds_area_msr)
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set_tsk_thread_flag(child, TIF_DS_AREA_MSR);
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else
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clear_tsk_thread_flag(child, TIF_DS_AREA_MSR);
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return retval;
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return sizeof(cfg);
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}
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void ptrace_bts_take_timestamp(struct task_struct *tsk,
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@@ -626,9 +666,6 @@ void ptrace_bts_take_timestamp(struct task_struct *tsk,
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.variant.jiffies = jiffies
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};
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if (ptrace_bts_get_buffer_size(tsk) <= 0)
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return;
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ptrace_bts_write_record(tsk, &rec);
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}
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@@ -808,30 +845,32 @@ long arch_ptrace(struct task_struct *child, long request, long addr, long data)
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break;
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#endif
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case PTRACE_BTS_MAX_BUFFER_SIZE:
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ret = ptrace_bts_max_buffer_size();
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break;
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case PTRACE_BTS_ALLOCATE_BUFFER:
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ret = ptrace_bts_allocate_bts(child, data);
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break;
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case PTRACE_BTS_GET_BUFFER_SIZE:
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ret = ptrace_bts_get_buffer_size(child);
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break;
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case PTRACE_BTS_READ_RECORD:
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ret = ptrace_bts_read_record
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(child, data,
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(struct bts_struct __user *) addr);
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break;
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case PTRACE_BTS_CONFIG:
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ret = ptrace_bts_config(child, data);
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ret = ptrace_bts_config
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(child, (struct ptrace_bts_config __user *)addr);
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break;
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case PTRACE_BTS_STATUS:
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ret = ptrace_bts_status(child);
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ret = ptrace_bts_status
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(child, (struct ptrace_bts_config __user *)addr);
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break;
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case PTRACE_BTS_SIZE:
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ret = ptrace_bts_get_size(child);
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break;
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case PTRACE_BTS_GET:
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ret = ptrace_bts_read_record
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(child, data, (struct bts_struct __user *) addr);
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break;
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case PTRACE_BTS_CLEAR:
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ret = ptrace_bts_clear(child);
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break;
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case PTRACE_BTS_DRAIN:
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ret = ptrace_bts_drain
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(child, (struct bts_struct __user *) addr);
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break;
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default:
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@@ -1017,12 +1056,12 @@ asmlinkage long sys32_ptrace(long request, u32 pid, u32 addr, u32 data)
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case PTRACE_SETOPTIONS:
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case PTRACE_SET_THREAD_AREA:
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case PTRACE_GET_THREAD_AREA:
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case PTRACE_BTS_MAX_BUFFER_SIZE:
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case PTRACE_BTS_ALLOCATE_BUFFER:
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case PTRACE_BTS_GET_BUFFER_SIZE:
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case PTRACE_BTS_READ_RECORD:
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case PTRACE_BTS_CONFIG:
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case PTRACE_BTS_STATUS:
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case PTRACE_BTS_SIZE:
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case PTRACE_BTS_GET:
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case PTRACE_BTS_CLEAR:
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case PTRACE_BTS_DRAIN:
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return sys_ptrace(request, pid, addr, data);
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default:
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