From 1d7ff84f126e5e1b138c7250a275ebe3a46fa27c Mon Sep 17 00:00:00 2001 From: Paul Rosenfeld Date: Tue, 4 Apr 2017 09:06:38 -0600 Subject: arm,sim: fix context switch stats dumps for ARM64/Linux 32bit and 64bit Linux have different arguments passed to the __switch_to() function that gem5 hooks into in order to collect context switch statistics. 64bit Linux provides the task_struct pointer to the next task that will be switched to, which means we don't have to look up the task_struct from thread_info as we do in 32bit ARM Linux. This patch adds a second set of accessors to ThreadInfo to extract details such as the pid, tgid, task name, etc., directly from a task_struct. The existing accessors maintain their existing behavior by first looking up the task_struct and then calling these new accessors. A 64-bit variant of the DumpStatsPCEvent class is added that uses these new accessors to get the task details for the context switch dumps directly from the task_struct passed to __switch_to(). Change-Id: I63c4b3e1ad64446751a91f6340901d5180d7382d Reviewed-on: https://gem5-review.googlesource.com/2640 Reviewed-by: Curtis Dunham Reviewed-by: Jason Lowe-Power Reviewed-by: Pau Cabre Reviewed-by: Andreas Sandberg Maintainer: Andreas Sandberg --- src/arch/arm/linux/system.cc | 68 +++++++++++++++++++++++++++++++++++++------- src/arch/arm/linux/system.hh | 14 +++++++++ 2 files changed, 71 insertions(+), 11 deletions(-) (limited to 'src/arch/arm/linux') diff --git a/src/arch/arm/linux/system.cc b/src/arch/arm/linux/system.cc index 52e075d8f..7f0647512 100644 --- a/src/arch/arm/linux/system.cc +++ b/src/arch/arm/linux/system.cc @@ -236,7 +236,14 @@ void LinuxArmSystem::startup() { if (enableContextSwitchStatsDump) { - dumpStatsPCEvent = addKernelFuncEvent("__switch_to"); + if (!highestELIs64()) { + dumpStatsPCEvent = + addKernelFuncEvent("__switch_to"); + } else { + dumpStatsPCEvent = + addKernelFuncEvent("__switch_to"); + } + if (!dumpStatsPCEvent) panic("dumpStatsPCEvent not created!"); @@ -276,25 +283,64 @@ LinuxArmSystem::dumpDmesg() Linux::dumpDmesg(getThreadContext(0), std::cout); } -/** This function is called whenever the the kernel function - * "__switch_to" is called to change running tasks. +/** + * Extracts the information used by the DumpStatsPCEvent by reading the + * thread_info pointer passed to __switch_to() in 32 bit ARM Linux * * r0 = task_struct of the previously running process - * r1 = task_info of the previously running process - * r2 = task_info of the next process to run + * r1 = thread_info of the previously running process + * r2 = thread_info of the next process to run */ void -DumpStatsPCEvent::process(ThreadContext *tc) -{ +DumpStatsPCEvent::getTaskDetails(ThreadContext *tc, uint32_t &pid, + uint32_t &tgid, std::string &next_task_str, int32_t &mm) { + Linux::ThreadInfo ti(tc); Addr task_descriptor = tc->readIntReg(2); - uint32_t pid = ti.curTaskPID(task_descriptor); - uint32_t tgid = ti.curTaskTGID(task_descriptor); - std::string next_task_str = ti.curTaskName(task_descriptor); + pid = ti.curTaskPID(task_descriptor); + tgid = ti.curTaskTGID(task_descriptor); + next_task_str = ti.curTaskName(task_descriptor); // Streamline treats pid == -1 as the kernel process. // Also pid == 0 implies idle process (except during Linux boot) - int32_t mm = ti.curTaskMm(task_descriptor); + mm = ti.curTaskMm(task_descriptor); +} + +/** + * Extracts the information used by the DumpStatsPCEvent64 by reading the + * task_struct pointer passed to __switch_to() in 64 bit ARM Linux + * + * r0 = task_struct of the previously running process + * r1 = task_struct of next process to run + */ +void +DumpStatsPCEvent64::getTaskDetails(ThreadContext *tc, uint32_t &pid, + uint32_t &tgid, std::string &next_task_str, int32_t &mm) { + + Linux::ThreadInfo ti(tc); + Addr task_struct = tc->readIntReg(1); + pid = ti.curTaskPIDFromTaskStruct(task_struct); + tgid = ti.curTaskTGIDFromTaskStruct(task_struct); + next_task_str = ti.curTaskNameFromTaskStruct(task_struct); + + // Streamline treats pid == -1 as the kernel process. + // Also pid == 0 implies idle process (except during Linux boot) + mm = ti.curTaskMmFromTaskStruct(task_struct); +} + +/** This function is called whenever the the kernel function + * "__switch_to" is called to change running tasks. + */ +void +DumpStatsPCEvent::process(ThreadContext *tc) +{ + uint32_t pid = 0; + uint32_t tgid = 0; + std::string next_task_str; + int32_t mm = 0; + + getTaskDetails(tc, pid, tgid, next_task_str, mm); + bool is_kernel = (mm == 0); if (is_kernel && (pid != 0)) { pid = -1; diff --git a/src/arch/arm/linux/system.hh b/src/arch/arm/linux/system.hh index 709776ffc..247ebae13 100644 --- a/src/arch/arm/linux/system.hh +++ b/src/arch/arm/linux/system.hh @@ -132,6 +132,20 @@ class DumpStatsPCEvent : public PCEvent {} virtual void process(ThreadContext* tc); + protected: + virtual void getTaskDetails(ThreadContext *tc, uint32_t &pid, + uint32_t &tgid, std::string &next_task_str, int32_t &mm); + +}; + +class DumpStatsPCEvent64 : public DumpStatsPCEvent { + public: + DumpStatsPCEvent64(PCEventQueue *q, const std::string &desc, Addr addr) + : DumpStatsPCEvent(q, desc, addr) + {} + private: + void getTaskDetails(ThreadContext *tc, uint32_t &pid, uint32_t &tgid, + std::string &next_task_str, int32_t &mm) override; }; -- cgit v1.2.3