| Message ID | 1412165279-8709-6-git-send-email-punit.agrawal@arm.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Wed, 1 Oct 2014 13:07:59 +0100 Punit Agrawal <punit.agrawal@arm.com> wrote: > Introduce an event to trace the usage of emulated instructions. The > trace event is intended to help identify and encourage the migration > of legacy software using the emulation features. > > Use this event to trace usage of swp and CP15 barrier emulation. Do you expect this to be a generic tracepoint? Something any arch can use, and more importantly, will use? If not, please keep this tracepoint in the arch/arm64 directories. The sample code in samples/trace_events/ explains how to do this. Thanks, -- Steve
[ Correcting Arnd's email address ] Hi Steve, Thanks for having a look. Steven Rostedt <rostedt@goodmis.org> writes: > On Wed, 1 Oct 2014 13:07:59 +0100 > Punit Agrawal <punit.agrawal@arm.com> wrote: > >> Introduce an event to trace the usage of emulated instructions. The >> trace event is intended to help identify and encourage the migration >> of legacy software using the emulation features. >> >> Use this event to trace usage of swp and CP15 barrier emulation. > > Do you expect this to be a generic tracepoint? Something any arch can > use, and more importantly, will use? The intention was to create a generic event to trace instruction emulation irrespective of the architecture but at the moment the only user will be arm64. Whether other architectures start using it... I am not sure. > > If not, please keep this tracepoint in the arch/arm64 directories. The > sample code in samples/trace_events/ explains how to do this. I'll move this to arm64 in the next version. > > Thanks, > > -- Steve > > > _______________________________________________ > linux-arm-kernel mailing list > linux-arm-kernel@lists.infradead.org > http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
diff --git a/arch/arm64/kernel/armv8_deprecated.c b/arch/arm64/kernel/armv8_deprecated.c index 53a6252..1726b3f 100644 --- a/arch/arm64/kernel/armv8_deprecated.c +++ b/arch/arm64/kernel/armv8_deprecated.c @@ -16,6 +16,9 @@ #include <linux/sched.h> #include <linux/sysctl.h> +#define CREATE_TRACE_POINTS +#include <trace/events/emulation.h> + #include <asm/insn.h> #include <asm/opcodes.h> #include <asm/system_misc.h> @@ -189,6 +192,11 @@ static int swp_handler(struct pt_regs *regs, u32 instr) regs->user_regs.regs[destreg] = data; ret: + if (type == TYPE_SWPB) + trace_instruction_emulation("swpb", regs->pc); + else + trace_instruction_emulation("swp", regs->pc); + pr_warn_ratelimited("\"%s\" (%ld) uses obsolete SWP{B} instruction at 0x%llx\n", current->comm, (unsigned long)current->pid, regs->pc); @@ -283,16 +291,23 @@ static int cp15barrier_handler(struct pt_regs *regs, u32 instr) * dmb - mcr p15, 0, Rt, c7, c10, 5 * dsb - mcr p15, 0, Rt, c7, c10, 4 */ - if (aarch32_insn_mcr_extract_opc2(instr) == 5) + if (aarch32_insn_mcr_extract_opc2(instr) == 5) { dmb(sy); - else + trace_instruction_emulation( + "mcr p15, 0, Rt, c7, c10, 5", regs->pc); + } else { dsb(sy); + trace_instruction_emulation( + "mcr p15, 0, Rt, c7, c10, 4", regs->pc); + } break; case 5: /* * isb - mcr p15, 0, Rt, c7, c5, 4 */ isb(); + trace_instruction_emulation( + "mcr p15, 0, Rt, c7, c5, 4", regs->pc); break; } diff --git a/include/trace/events/emulation.h b/include/trace/events/emulation.h new file mode 100644 index 0000000..e77726a --- /dev/null +++ b/include/trace/events/emulation.h @@ -0,0 +1,35 @@ +#undef TRACE_SYSTEM +#define TRACE_SYSTEM emulation + +#if !defined(_TRACE_EMULATION_H) || defined(TRACE_HEADER_MULTI_READ) +#define _TRACE_EMULATION_H + +#include <linux/tracepoint.h> + +TRACE_EVENT(instruction_emulation, + + TP_PROTO(const char *instr, u64 addr), + TP_ARGS(instr, addr), + + TP_STRUCT__entry( + __array(char, comm, TASK_COMM_LEN) + __field(pid_t, pid) + __string(instr, instr) + __field(u64, addr) + ), + + TP_fast_assign( + memcpy(__entry->comm, current->comm, TASK_COMM_LEN); + __entry->pid = current->pid; + __assign_str(instr, instr); + __entry->addr = addr; + ), + + TP_printk("instr=%s comm=%s pid=%d addr=0x%llx", __get_str(instr), + __entry->comm, __entry->pid, __entry->addr) +); + +#endif /* _TRACE_EMULATION_H */ + +/* This part must be outside protection */ +#include <trace/define_trace.h>
Introduce an event to trace the usage of emulated instructions. The trace event is intended to help identify and encourage the migration of legacy software using the emulation features. Use this event to trace usage of swp and CP15 barrier emulation. Cc: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Punit Agrawal <punit.agrawal@arm.com> --- arch/arm64/kernel/armv8_deprecated.c | 19 ++++++++++++++++-- include/trace/events/emulation.h | 35 ++++++++++++++++++++++++++++++++++ 2 files changed, 52 insertions(+), 2 deletions(-) create mode 100644 include/trace/events/emulation.h