From 93fa7636dfdc059b25df148f230c0991096afdef Mon Sep 17 00:00:00 2001 From: Markus Metzger Date: Tue, 8 Apr 2008 11:01:58 +0200 Subject: x86, ptrace: PEBS support Polish the ds.h interface and add support for PEBS. Ds.c is meant to be the resource allocator for per-thread and per-cpu BTS and PEBS recording. It is used by ptrace/utrace to provide execution tracing of debugged tasks. It will be used by profilers (e.g. perfmon2). It may be used by kernel debuggers to provide a kernel execution trace. Changes in detail: - guard DS and ptrace by CONFIG macros - separate DS and BTS more clearly - simplify field accesses - add functions to manage PEBS buffers - add simple protection/allocation mechanism - added support for Atom Opens: - buffer overflow handling Currently, only circular buffers are supported. This is all we need for debugging. Profilers would want an overflow notification. This is planned to be added when perfmon2 is made to use the ds.h interface. - utrace intermediate layer Signed-off-by: Markus Metzger Signed-off-by: Ingo Molnar Signed-off-by: Thomas Gleixner --- arch/x86/kernel/process_32.c | 25 +++++++++++++++++++++---- 1 file changed, 21 insertions(+), 4 deletions(-) (limited to 'arch/x86/kernel/process_32.c') diff --git a/arch/x86/kernel/process_32.c b/arch/x86/kernel/process_32.c index f8476dfbb60d..5cec8a75a4e8 100644 --- a/arch/x86/kernel/process_32.c +++ b/arch/x86/kernel/process_32.c @@ -316,6 +316,14 @@ void exit_thread(void) tss->x86_tss.io_bitmap_base = INVALID_IO_BITMAP_OFFSET; put_cpu(); } +#ifdef CONFIG_X86_DS + /* Free any DS contexts that have not been properly released. */ + if (unlikely(current->thread.ds_ctx)) { + /* we clear debugctl to make sure DS is not used. */ + update_debugctlmsr(0); + ds_free(current->thread.ds_ctx); + } +#endif /* CONFIG_X86_DS */ } void flush_thread(void) @@ -482,18 +490,27 @@ __switch_to_xtra(struct task_struct *prev_p, struct task_struct *next_p, { struct thread_struct *prev, *next; unsigned long debugctl; + unsigned long ds_prev = 0, ds_next = 0; prev = &prev_p->thread; next = &next_p->thread; debugctl = prev->debugctlmsr; - if (next->ds_area_msr != prev->ds_area_msr) { + +#ifdef CONFIG_X86_DS + if (prev->ds_ctx) + ds_prev = (unsigned long)prev->ds_ctx->ds; + if (next->ds_ctx) + ds_next = (unsigned long)next->ds_ctx->ds; + + if (ds_next != ds_prev) { /* we clear debugctl to make sure DS * is not in use when we change it */ debugctl = 0; update_debugctlmsr(0); - wrmsr(MSR_IA32_DS_AREA, next->ds_area_msr, 0); + wrmsr(MSR_IA32_DS_AREA, ds_next, 0); } +#endif /* CONFIG_X86_DS */ if (next->debugctlmsr != debugctl) update_debugctlmsr(next->debugctlmsr); @@ -517,13 +534,13 @@ __switch_to_xtra(struct task_struct *prev_p, struct task_struct *next_p, hard_enable_TSC(); } -#ifdef X86_BTS +#ifdef CONFIG_X86_PTRACE_BTS if (test_tsk_thread_flag(prev_p, TIF_BTS_TRACE_TS)) ptrace_bts_take_timestamp(prev_p, BTS_TASK_DEPARTS); if (test_tsk_thread_flag(next_p, TIF_BTS_TRACE_TS)) ptrace_bts_take_timestamp(next_p, BTS_TASK_ARRIVES); -#endif +#endif /* CONFIG_X86_PTRACE_BTS */ if (!test_tsk_thread_flag(next_p, TIF_IO_BITMAP)) { -- cgit v1.2.1 From 970e725098a6da5a9c1f8128102c812e31a0444c Mon Sep 17 00:00:00 2001 From: Andrew Morton Date: Wed, 16 Apr 2008 16:40:17 -0700 Subject: x86, ptrace: PEBS support, warning fix arch/x86/kernel/process_32.c:566: warning: unused variable 'ds_next' arch/x86/kernel/process_32.c:566: warning: unused variable 'ds_prev' Cc: Markus Metzger Cc: Andi Kleen Cc: "H. Peter Anvin" Cc: "Siddha, Suresh B" Cc: Roland McGrath Cc: Michael Kerrisk Cc: Cc: stephane eranian Cc: Jason Wessel Signed-off-by: Andrew Morton Signed-off-by: Ingo Molnar Signed-off-by: Thomas Gleixner --- arch/x86/kernel/process_32.c | 37 +++++++++++++++++++++++++------------ 1 file changed, 25 insertions(+), 12 deletions(-) (limited to 'arch/x86/kernel/process_32.c') diff --git a/arch/x86/kernel/process_32.c b/arch/x86/kernel/process_32.c index 5cec8a75a4e8..496ea3110aa2 100644 --- a/arch/x86/kernel/process_32.c +++ b/arch/x86/kernel/process_32.c @@ -484,20 +484,13 @@ int set_tsc_mode(unsigned int val) return 0; } -static noinline void -__switch_to_xtra(struct task_struct *prev_p, struct task_struct *next_p, - struct tss_struct *tss) +#ifdef CONFIG_X86_DS +static int update_debugctl(struct thread_struct *prev, + struct thread_struct *next, unsigned long debugctl) { - struct thread_struct *prev, *next; - unsigned long debugctl; - unsigned long ds_prev = 0, ds_next = 0; + unsigned long ds_prev = 0; + unsigned long ds_next = 0; - prev = &prev_p->thread; - next = &next_p->thread; - - debugctl = prev->debugctlmsr; - -#ifdef CONFIG_X86_DS if (prev->ds_ctx) ds_prev = (unsigned long)prev->ds_ctx->ds; if (next->ds_ctx) @@ -510,8 +503,28 @@ __switch_to_xtra(struct task_struct *prev_p, struct task_struct *next_p, update_debugctlmsr(0); wrmsr(MSR_IA32_DS_AREA, ds_next, 0); } + return debugctl; +} +#else +static int update_debugctl(struct thread_struct *prev, + struct thread_struct *next, unsigned long debugctl) +{ + return debugctl; +} #endif /* CONFIG_X86_DS */ +static noinline void +__switch_to_xtra(struct task_struct *prev_p, struct task_struct *next_p, + struct tss_struct *tss) +{ + struct thread_struct *prev, *next; + unsigned long debugctl; + + prev = &prev_p->thread; + next = &next_p->thread; + + debugctl = update_debugctl(prev, next, prev->debugctlmsr); + if (next->debugctlmsr != debugctl) update_debugctlmsr(next->debugctlmsr); -- cgit v1.2.1