x86, ptrace: support for branch trace store(BTS)
Resend using different mail client Changes to the last version: - split implementation into two layers: ds/bts and ptrace - renamed TIF's - save/restore ds save area msr in __switch_to_xtra() - make block-stepping only look at BTF bit Signed-off-by: Markus Metzger <markus.t.metzger@intel.com> Signed-off-by: Suresh Siddha <suresh.b.siddha@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
7796931f54
commit
eee3af4a2c
@ -2,6 +2,9 @@
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/*
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* Pentium III FXSR, SSE support
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* Gareth Hughes <gareth@valinux.com>, May 2000
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*
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* BTS tracing
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* Markus Metzger <markus.t.metzger@intel.com>, Dec 2007
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*/
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#include <linux/kernel.h>
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@ -26,6 +29,14 @@
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#include <asm/desc.h>
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#include <asm/prctl.h>
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#include <asm/proto.h>
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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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@ -455,6 +466,165 @@ 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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{
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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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}
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static int ptrace_bts_get_index(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_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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long index,
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struct bts_struct __user *out)
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{
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struct bts_struct ret;
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int retval;
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if (!child->thread.ds_area_msr)
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return -ENXIO;
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retval = ds_read_bts((void *)child->thread.ds_area_msr,
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index, &ret);
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if (retval)
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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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return sizeof(ret);
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}
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static int ptrace_bts_write_record(struct task_struct *child,
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const struct bts_struct *in)
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{
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int retval;
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if (!child->thread.ds_area_msr)
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return -ENXIO;
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retval = ds_write_bts((void *)child->thread.ds_area_msr, in);
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if (retval)
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return retval;
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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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{
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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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return -ENXIO;
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if (options & PTRACE_BTS_O_TRACE_TASK) {
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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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/* there is no way for us to check whether we 'own'
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* the respective bits in the DEBUGCTL MSR, we're
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* about to clear */
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child->thread.debugctlmsr &= ~debugctl_mask;
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if (!child->thread.debugctlmsr)
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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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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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return 0;
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}
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static int ptrace_bts_status(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, status = 0;
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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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if (ptrace_bts_get_buffer_size(child) <= 0)
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return -ENXIO;
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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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return status;
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}
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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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}
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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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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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}
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void ptrace_bts_take_timestamp(struct task_struct *tsk,
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enum bts_qualifier qualifier)
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{
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struct bts_struct rec = {
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.qualifier = qualifier,
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.variant.timestamp = sched_clock()
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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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/*
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* Called by kernel/ptrace.c when detaching..
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*
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@ -466,6 +636,11 @@ void ptrace_disable(struct task_struct *child)
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#ifdef TIF_SYSCALL_EMU
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clear_tsk_thread_flag(child, TIF_SYSCALL_EMU);
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#endif
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ptrace_bts_config(child, /* options = */ 0);
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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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clear_tsk_thread_flag(child, TIF_DS_AREA_MSR);
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}
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}
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long arch_ptrace(struct task_struct *child, long request, long addr, long data)
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@ -626,6 +801,36 @@ 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_GET_INDEX:
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ret = ptrace_bts_get_index(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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break;
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case PTRACE_BTS_STATUS:
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ret = ptrace_bts_status(child);
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break;
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default:
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ret = ptrace_request(child, request, addr, data);
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break;
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@ -809,6 +1014,13 @@ 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_GET_INDEX:
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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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return sys_ptrace(request, pid, addr, data);
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default:
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