Re: [BUG/RFC] perf test fails on AMD CPUs

[Jiri Olsa <jolsa@redhat.com>]

On Wed, Aug 19, 2015 at 05:55:19AM +0200, Borislav Petkov wrote:
> On Tue, Aug 18, 2015 at 12:10:25PM +0200, Jiri Olsa wrote:
> > buuuuuut anyway, it looks like latest AMD firmware issue:
> > 
> > [root@amd-pike-07 ~]# cat /sys/devices/system/cpu/cpu0/microcode/version
> > 0x6000822
> > [root@amd-pike-07 perf]# ./perf test 18
> > 18: Test breakpoint overflow signal handler                  : Ok
> > 
> > [root@amd-pike-07 perf]# cat /sys/devices/system/cpu/cpu0/microcode/version
> > 0x6000832
> > [root@amd-pike-07 perf]# ./perf test 18
> > 18: Test breakpoint overflow signal handler                  : FAILED!
> > 
> > 
> > [root@amd-pike-07 ~]# cat /proc/cpuinfo 
> > processor       : 7
> > vendor_id       : AuthenticAMD
> > cpu family      : 21
> > model           : 2
> > model name      : AMD Opteron(tm) Processor 3380
> > stepping        : 0
> > microcode       : 0x6000832
> > 
> > SNIP
> 
> Whoops.
> 
> Can you please confirm with your debugging code that with version
> 0x6000822 EFLAGS.RF is set and with 0x6000832 it isn't when running the
> aforementioned test?
> 

please check the attached patch (over current tip/master a987577)


this is the perf breakpoint address:
  000000000045b260 <test_function>:

this is trace_printk output for NEW microcode 0x6000832:

DEBUG EX
            perf-893   [003] d...  1358.053633: sync_regs: sync_regs eregs ffff88012ecc7f58, regs ffff8800c9f1bf58
            perf-893   [003] d...  1358.053635: do_debug: do_debug-1 regs ffff8800c9f1bf58, eflags 217, rip 45b260
            perf-893   [003] d.h.  1358.053641: do_debug: do_debug-2 eflags 10217, rip 45b260
            perf-893   [003] d...  1358.053642: prepare_exit_to_usermode: prepare_exit_to_usermode1 regs ffff8800c9f1bf58, eflags 10217, rip 45b260
            perf-893   [003] d...  1358.053643: prepare_exit_to_usermode: prepare_exit_to_usermode3 regs ffff8800c9f1bf58, eflags 10217, rip 45b260

WORK_IRQ
 --->       perf-893   [003] d...  1358.053645: smp_irq_work_interrupt: smp_irq_work_interrupt1 regs ffff8800c9f1bf58, eflags 217, rip 45b260
            perf-893   [003] d.h.  1358.053650: perf_event_wakeup: irq_work SIGIO
            perf-893   [003] d...  1358.053651: smp_irq_work_interrupt: smp_irq_work_interrupt2 regs ffff8800c9f1bf58, eflags 217, rip 45b260

            perf-893   [003] d...  1358.053652: prepare_exit_to_usermode: prepare_exit_to_usermode1 regs ffff8800c9f1bf58, eflags 217, rip 45b260



this is trace_printk output for OLD microcode 0x6000822:

DEBUG EX
            perf-898   [005] d...    87.098816: sync_regs: sync_regs eregs ffff88012ed47f58, regs ffff8800c9c8ff58
            perf-898   [005] d...    87.098817: do_debug: do_debug-1 regs ffff8800c9c8ff58, eflags 217, rip 45b260
            perf-898   [005] d.h.    87.098823: do_debug: do_debug-2 eflags 10217, rip 45b260
            perf-898   [005] d...    87.098824: prepare_exit_to_usermode: prepare_exit_to_usermode1 regs ffff8800c9c8ff58, eflags 10217, rip 45b260
            perf-898   [005] d...    87.098825: prepare_exit_to_usermode: prepare_exit_to_usermode3 regs ffff8800c9c8ff58, eflags 10217, rip 45b260

WORK_IRQ
 --->       perf-898   [005] d...    87.098827: smp_irq_work_interrupt: smp_irq_work_interrupt1 regs ffff8800c9c8ff58, eflags 10217, rip 45b260
            perf-898   [005] d.h.    87.098832: perf_event_wakeup: irq_work SIGIO
            perf-898   [005] d...    87.098833: smp_irq_work_interrupt: smp_irq_work_interrupt2 regs ffff8800c9c8ff58, eflags 10217, rip 45b260

            perf-898   [005] d...    87.098833: prepare_exit_to_usermode: prepare_exit_to_usermode1 regs ffff8800c9c8ff58, eflags 10217, rip 45b260


thanks,
jirka


---
diff --git a/arch/x86/entry/common.c b/arch/x86/entry/common.c
index 80dcc92..d52d598 100644
--- a/arch/x86/entry/common.c
+++ b/arch/x86/entry/common.c
@@ -217,6 +217,8 @@ static struct thread_info *pt_regs_to_thread_info(struct pt_regs *regs)
 /* Called with IRQs disabled. */
 __visible void prepare_exit_to_usermode(struct pt_regs *regs)
 {
+	trace_printk("prepare_exit_to_usermode1 regs %p, eflags %lx, rip %lx\n", regs, regs->flags, regs->ip);
+
 	if (WARN_ON(!irqs_disabled()))
 		local_irq_disable();
 
@@ -263,6 +265,7 @@ __visible void prepare_exit_to_usermode(struct pt_regs *regs)
 	}
 
 	user_enter();
+	trace_printk("prepare_exit_to_usermode3 regs %p, eflags %lx, rip %lx\n", regs, regs->flags, regs->ip);
 }
 
 /*
diff --git a/arch/x86/kernel/irq_work.c b/arch/x86/kernel/irq_work.c
index dc5fa6a..52fe376 100644
--- a/arch/x86/kernel/irq_work.c
+++ b/arch/x86/kernel/irq_work.c
@@ -18,9 +18,13 @@ static inline void __smp_irq_work_interrupt(void)
 
 __visible void smp_irq_work_interrupt(struct pt_regs *regs)
 {
+	trace_printk("smp_irq_work_interrupt1 regs %p, eflags %lx, rip %lx\n", regs, regs->flags, regs->ip);
+
 	ipi_entering_ack_irq();
 	__smp_irq_work_interrupt();
 	exiting_irq();
+
+	trace_printk("smp_irq_work_interrupt2 regs %p, eflags %lx, rip %lx\n", regs, regs->flags, regs->ip);
 }
 
 __visible void smp_trace_irq_work_interrupt(struct pt_regs *regs)
diff --git a/arch/x86/kernel/signal.c b/arch/x86/kernel/signal.c
index da52e6b..cb199dc 100644
--- a/arch/x86/kernel/signal.c
+++ b/arch/x86/kernel/signal.c
@@ -398,6 +398,7 @@ static int __setup_rt_frame(int sig, struct ksignal *ksig,
 	regs->ss = __USER_DS;
 	regs->cs = __USER_CS;
 
+trace_printk("__setup_rt_frame regs %p, eflags %lx, rip %lx\n", regs, regs->flags, regs->ip);
 	return 0;
 }
 #else /* !CONFIG_X86_32 */
@@ -583,6 +584,7 @@ asmlinkage long sys_rt_sigreturn(void)
 	if (restore_altstack(&frame->uc.uc_stack))
 		goto badframe;
 
+trace_printk("sys_rt_sigreturn regs %p, eflags %lx, rip %lx\n", regs, regs->flags, regs->ip);
 	return regs->ax;
 
 badframe:
diff --git a/arch/x86/kernel/traps.c b/arch/x86/kernel/traps.c
index bfc4f90..cee75d8 100644
--- a/arch/x86/kernel/traps.c
+++ b/arch/x86/kernel/traps.c
@@ -536,6 +536,7 @@ asmlinkage __visible notrace struct pt_regs *sync_regs(struct pt_regs *eregs)
 {
 	struct pt_regs *regs = task_pt_regs(current);
 	*regs = *eregs;
+trace_printk("sync_regs eregs %p, regs %p\n", eregs, regs);
 	return regs;
 }
 NOKPROBE_SYMBOL(sync_regs);
@@ -602,6 +603,8 @@ dotraplinkage void do_debug(struct pt_regs *regs, long error_code)
 	unsigned long dr6;
 	int si_code;
 
+trace_printk("do_debug-1 regs %p, eflags %lx, rip %lx\n", regs, regs->flags, regs->ip);
+
 	ist_enter(regs);
 
 	get_debugreg(dr6, 6);
@@ -677,6 +680,7 @@ dotraplinkage void do_debug(struct pt_regs *regs, long error_code)
 	debug_stack_usage_dec();
 
 exit:
+	trace_printk("do_debug-2 eflags %lx, rip %lx\n", regs->flags, regs->ip);
 	ist_exit(regs);
 }
 NOKPROBE_SYMBOL(do_debug);
diff --git a/kernel/events/core.c b/kernel/events/core.c
index ae16867..6977f20 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -4803,6 +4803,7 @@ void perf_event_wakeup(struct perf_event *event)
 
 	if (event->pending_kill) {
 		kill_fasync(perf_event_fasync(event), SIGIO, event->pending_kill);
+trace_printk("irq_work SIGIO\n");
 		event->pending_kill = 0;
 	}
 }