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kern, arm: Dump dmesg on kernel panic/oops

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Add helper functions to dump the guest kernel's dmesg buffer to a text
file in m5out. This functionality is split into two parts. First, a
dmesg dump function that can be used in other places:

void Linux::dumpDmesg(ThreadContext *, std::ostream &)

This function is used to implement two PCEvents: DmesgDumpEvent and
KernelPanic event. The only difference between the two is that the
latter produces a gem5 panic instead of a warning in addition to
dumping the kernel log.

Change-Id: I6d2af1d666ace57124089648ea906f6c787ac63c
Signed-off-by: Andreas Sandberg <andreas.sandberg@arm.com>
Reviewed-by: Nikos Nikoleris <nikos.nikoleris@arm.com>
Reviewed-by: Gabor Dozsa <gabor.dozsa@arm.com>
This commit is contained in:
Andreas Sandberg 2016-06-20 14:39:49 +01:00
parent 60fb5e79f3
commit 37bb0d0fb3
8 changed files with 324 additions and 7 deletions
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8
src/arch/arm/ArmSystem.py
View file

@ -98,6 +98,14 @@ class LinuxArmSystem(GenericArmSystem):
type = 'LinuxArmSystem'
cxx_header = "arch/arm/linux/system.hh"
@classmethod
def export_method_cxx_predecls(cls, code):
code('#include "arch/arm/linux/system.hh"')
@classmethod
def export_methods(cls, code):
code('''void dumpDmesg();''')
class FreebsdArmSystem(GenericArmSystem):
type = 'FreebsdArmSystem'
cxx_header = "arch/arm/freebsd/system.hh"

24
src/arch/arm/linux/system.cc
View file

@ -1,5 +1,5 @@
/*
* Copyright (c) 2010-2013 ARM Limited
* Copyright (c) 2010-2013, 2016 ARM Limited
* All rights reserved
*
* The license below extends only to copyright in the software and shall
@ -53,6 +53,7 @@
#include "cpu/thread_context.hh"
#include "debug/Loader.hh"
#include "kern/linux/events.hh"
#include "kern/linux/helpers.hh"
#include "mem/fs_translating_port_proxy.hh"
#include "mem/physical.hh"
#include "sim/stat_control.hh"
@ -65,14 +66,21 @@ LinuxArmSystem::LinuxArmSystem(Params *p)
enableContextSwitchStatsDump(p->enable_context_switch_stats_dump),
taskFile(nullptr), kernelPanicEvent(nullptr), kernelOopsEvent(nullptr)
{
const std::string dmesg_output = name() + ".dmesg";
if (p->panic_on_panic) {
kernelPanicEvent = addKernelFuncEventOrPanic<PanicPCEvent>(
"panic", "Kernel panic in simulated kernel");
kernelPanicEvent = addKernelFuncEventOrPanic<Linux::KernelPanicEvent>(
"panic", "Kernel panic in simulated kernel", dmesg_output);
} else {
kernelPanicEvent = addKernelFuncEventOrPanic<Linux::DmesgDumpEvent>(
"panic", "Kernel panic in simulated kernel", dmesg_output);
}
if (p->panic_on_oops) {
kernelOopsEvent = addKernelFuncEventOrPanic<PanicPCEvent>(
"oops_exit", "Kernel oops in guest");
kernelOopsEvent = addKernelFuncEventOrPanic<Linux::KernelPanicEvent>(
"oops_exit", "Kernel oops in guest", dmesg_output);
} else {
kernelOopsEvent = addKernelFuncEventOrPanic<Linux::DmesgDumpEvent>(
"oops_exit", "Kernel oops in guest", dmesg_output);
}
// With ARM udelay() is #defined to __udelay
@ -261,6 +269,12 @@ LinuxArmSystem::mapPid(ThreadContext *tc, uint32_t pid)
}
}
void
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.
*

6
src/arch/arm/linux/system.hh
View file

@ -95,6 +95,12 @@ class LinuxArmSystem : public GenericArmSystem
* @param tc thread context that is currentyl executing */
void mapPid(ThreadContext* tc, uint32_t pid);
public: // Exported Python methods
/**
* Dump the kernel's dmesg buffer to stdout
*/
void dumpDmesg();
private:
/** Event to halt the simulator if the kernel calls panic() */
PCEvent *kernelPanicEvent;

1
src/kern/SConscript
View file

@ -36,6 +36,7 @@ if env['TARGET_ISA'] == 'null':
Source('kernel_stats.cc')
Source('linux/events.cc')
Source('linux/linux.cc')
Source('linux/helpers.cc')
Source('linux/printk.cc')
Source('freebsd/events.cc')
Source('operatingsystem.cc')

33
src/kern/linux/events.cc
View file

@ -1,5 +1,5 @@
/*
* Copyright (c) 2011 ARM Limited
* Copyright (c) 2011, 2016 ARM Limited
* All rights reserved
*
* The license below extends only to copyright in the software and shall
@ -41,13 +41,17 @@
* Ali Saidi
*/
#include "kern/linux/events.hh"
#include <sstream>
#include "arch/utility.hh"
#include "base/output.hh"
#include "base/trace.hh"
#include "cpu/base.hh"
#include "cpu/thread_context.hh"
#include "debug/DebugPrintf.hh"
#include "kern/linux/events.hh"
#include "kern/linux/helpers.hh"
#include "kern/linux/printk.hh"
#include "kern/system_events.hh"
#include "sim/arguments.hh"
@ -94,5 +98,30 @@ UDelayEvent::process(ThreadContext *tc)
}
}
void
DmesgDumpEvent::process(ThreadContext *tc)
{
StringWrap name(tc->getCpuPtr()->name() + ".dmesg_dump_event");
inform("Dumping kernel dmesg buffer to %s...\n", fname);
OutputStream *os = simout.create(fname);
dumpDmesg(tc, *os->stream());
simout.close(os);
warn(descr());
}
void
KernelPanicEvent::process(ThreadContext *tc)
{
StringWrap name(tc->getCpuPtr()->name() + ".dmesg_dump_event");
inform("Dumping kernel dmesg buffer to %s...\n", fname);
OutputStream *os = simout.create(fname);
dumpDmesg(tc, *os->stream());
simout.close(os);
panic(descr());
}
} // namespace linux

52
src/kern/linux/events.hh
View file

@ -1,4 +1,16 @@
/*
* Copyright (c) 2016 ARM Limited
* All rights reserved
*
* The license below extends only to copyright in the software and shall
* not be construed as granting a license to any other intellectual
* property including but not limited to intellectual property relating
* to a hardware implementation of the functionality of the software
* licensed hereunder. You may use the software subject to the license
* terms below provided that you ensure that this notice is replicated
* unmodified and in its entirety in all distributions of the software,
* modified or unmodified, in source code or in binary form.
*
* Copyright (c) 2004-2006 The Regents of The University of Michigan
* All rights reserved.
*
@ -44,6 +56,46 @@ class DebugPrintkEvent : public SkipFuncEvent
virtual void process(ThreadContext *xc);
};
/**
* Dump the guest kernel's dmesg buffer to a file in gem5's output
* directory and print a warning.
*
* @warn This event uses Linux::dumpDmesg() and comes with the same
* limitations. Most importantly, the kernel's address mappings must
* be available to the translating proxy.
*/
class DmesgDumpEvent : public PCEvent
{
protected:
std::string fname;
public:
DmesgDumpEvent(PCEventQueue *q, const std::string &desc, Addr addr,
const std::string &_fname)
: PCEvent(q, desc, addr), fname(_fname) {}
virtual void process(ThreadContext *xc);
};
/**
* Dump the guest kernel's dmesg buffer to a file in gem5's output
* directory and panic.
*
* @warn This event uses Linux::dumpDmesg() and comes with the same
* limitations. Most importantly, the kernel's address mappings must
* be available to the translating proxy.
*/
class KernelPanicEvent : public PCEvent
{
protected:
std::string fname;
public:
KernelPanicEvent(PCEventQueue *q, const std::string &desc, Addr addr,
const std::string &_fname)
: PCEvent(q, desc, addr), fname(_fname) {}
virtual void process(ThreadContext *xc);
};
/** A class to skip udelay() and related calls in the kernel.
* This class has two additional parameters that take the argument to udelay and
* manipulated it to come up with ns and eventually ticks to quiesce for.

148
src/kern/linux/helpers.cc Normal file
View file

@ -0,0 +1,148 @@
/*
* Copyright (c) 2016 ARM Limited
* All rights reserved
*
* The license below extends only to copyright in the software and shall
* not be construed as granting a license to any other intellectual
* property including but not limited to intellectual property relating
* to a hardware implementation of the functionality of the software
* licensed hereunder. You may use the software subject to the license
* terms below provided that you ensure that this notice is replicated
* unmodified and in its entirety in all distributions of the software,
* modified or unmodified, in source code or in binary form.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are
* met: redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer;
* redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution;
* neither the name of the copyright holders nor the names of its
* contributors may be used to endorse or promote products derived from
* this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
* OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*
* Authors: Andreas Sandberg
*/
#include "kern/linux/helpers.hh"
#include "arch/isa_traits.hh"
#include "config/the_isa.hh"
#include "cpu/thread_context.hh"
#include "mem/fs_translating_port_proxy.hh"
#include "sim/system.hh"
struct DmesgEntry {
uint64_t ts_nsec;
uint16_t len;
uint16_t text_len;
uint16_t dict_len;
uint8_t facility;
uint8_t flags;
} M5_ATTR_PACKED;
static int
dumpDmesgEntry(const uint8_t *base, const uint8_t *end, std::ostream &os)
{
const size_t max_length = end - base;
DmesgEntry de;
if (max_length < sizeof(de)) {
warn("Malformed dmesg entry\n");
return -1;
}
memcpy(&de, base, sizeof(de));
de.ts_nsec = TheISA::gtoh(de.ts_nsec);
de.len = TheISA::gtoh(de.len);
de.text_len = TheISA::gtoh(de.text_len);
if (de.len < sizeof(de) ||
max_length < de.len ||
max_length < sizeof(DmesgEntry) + de.text_len) {
warn("Malformed dmesg entry:\n");
warn("\tMax length: %i\n", max_length);
warn("\tde.len: %i\n", de.len);
warn("\tde.text_len: %i\n", de.text_len);
return -1;
}
ccprintf(os, "[%.6f] ", de.ts_nsec * 10e-9);
os.write((char *)base + sizeof(de), de.text_len);
os << std::endl;
return de.len;
}
void
Linux::dumpDmesg(ThreadContext *tc, std::ostream &os)
{
System *system = tc->getSystemPtr();
const SymbolTable *symtab = system->kernelSymtab;
FSTranslatingPortProxy proxy(tc);
Addr addr_lb = 0, addr_lb_len = 0, addr_first = 0, addr_next = 0;
const bool found_symbols =
symtab->findAddress("__log_buf", addr_lb) &&
symtab->findAddress("log_buf_len", addr_lb_len) &&
symtab->findAddress("log_first_idx", addr_first) &&
symtab->findAddress("log_next_idx", addr_next);
if (!found_symbols) {
warn("Failed to find kernel dmesg symbols.\n");
return;
}
uint32_t log_buf_len = proxy.readGtoH<uint32_t>(addr_lb_len);
uint32_t log_first_idx = proxy.readGtoH<uint32_t>(addr_first);
uint32_t log_next_idx = proxy.readGtoH<uint32_t>(addr_next);
if (log_first_idx >= log_buf_len || log_next_idx >= log_buf_len) {
warn("dmesg pointers/length corrupted\n");
return;
}
// Normalize and read the dmesg ring buffer
std::vector<uint8_t> log_buf(log_buf_len);
int length;
if (log_first_idx < log_next_idx) {
length = log_next_idx - log_first_idx;
if (length < 0 || length > log_buf.size()) {
warn("Unexpected dmesg buffer length\n");
return;
}
proxy.readBlob(addr_lb + log_first_idx, log_buf.data(), length);
} else {
const int length_2 = log_buf_len - log_first_idx;
if (length_2 < 0 || length_2 + log_next_idx > log_buf.size()) {
warn("Unexpected dmesg buffer length\n");
return;
}
length = log_buf_len;
proxy.readBlob(addr_lb + log_first_idx, log_buf.data(), length_2);
proxy.readBlob(addr_lb, log_buf.data() + length_2, log_next_idx);
}
// Print dmesg buffer content
const uint8_t *cur = log_buf.data(), *end = log_buf.data() + length;
while (cur < end) {
int ret = dumpDmesgEntry(cur, end, os);
if (ret < 0)
return;
cur += ret;
}
}

59
src/kern/linux/helpers.hh Normal file
View file

@ -0,0 +1,59 @@
/*
* Copyright (c) 2016 ARM Limited
* All rights reserved
*
* The license below extends only to copyright in the software and shall
* not be construed as granting a license to any other intellectual
* property including but not limited to intellectual property relating
* to a hardware implementation of the functionality of the software
* licensed hereunder. You may use the software subject to the license
* terms below provided that you ensure that this notice is replicated
* unmodified and in its entirety in all distributions of the software,
* modified or unmodified, in source code or in binary form.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are
* met: redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer;
* redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution;
* neither the name of the copyright holders nor the names of its
* contributors may be used to endorse or promote products derived from
* this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
* OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*
* Authors: Andreas Sandberg
*/
#ifndef __KERN_LINUX_HELPERS_HH__
#define __KERN_LINUX_HELPERS_HH__
#include <ostream>
class ThreadContext;
namespace Linux {
/**
* Dump Linux's dmesg log buffer to the an output stream.
*
* @warn This assumes that the kernel address mappings are available
* to the translating proxy.
*/
void dumpDmesg(ThreadContext *tc, std::ostream &os);
} // namespace Linux
#endif // __KERN_LINUX_HELPERS_HH__