kernel.git/arch/x86/kernel/apic/Makefile, branch linux-4.7.y

kernel: add kcov code coverage

2016-03-22T22:36:02Z

kcov provides code coverage collection for coverage-guided fuzzing (randomized testing). Coverage-guided fuzzing is a testing technique that uses coverage feedback to determine new interesting inputs to a system. A notable user-space example is AFL (http://lcamtuf.coredump.cx/afl/). However, this technique is not widely used for kernel testing due to missing compiler and kernel support. kcov does not aim to collect as much coverage as possible. It aims to collect more or less stable coverage that is function of syscall inputs. To achieve this goal it does not collect coverage in soft/hard interrupts and instrumentation of some inherently non-deterministic or non-interesting parts of kernel is disbled (e.g. scheduler, locking). Currently there is a single coverage collection mode (tracing), but the API anticipates additional collection modes. Initially I also implemented a second mode which exposes coverage in a fixed-size hash table of counters (what Quentin used in his original patch). I've dropped the second mode for simplicity. This patch adds the necessary support on kernel side. The complimentary compiler support was added in gcc revision 231296. We've used this support to build syzkaller system call fuzzer, which has found 90 kernel bugs in just 2 months: https://github.com/google/syzkaller/wiki/Found-Bugs We've also found 30+ bugs in our internal systems with syzkaller. Another (yet unexplored) direction where kcov coverage would greatly help is more traditional "blob mutation". For example, mounting a random blob as a filesystem, or receiving a random blob over wire. Why not gcov. Typical fuzzing loop looks as follows: (1) reset coverage, (2) execute a bit of code, (3) collect coverage, repeat. A typical coverage can be just a dozen of basic blocks (e.g. an invalid input). In such context gcov becomes prohibitively expensive as reset/collect coverage steps depend on total number of basic blocks/edges in program (in case of kernel it is about 2M). Cost of kcov depends only on number of executed basic blocks/edges. On top of that, kernel requires per-thread coverage because there are always background threads and unrelated processes that also produce coverage. With inlined gcov instrumentation per-thread coverage is not possible. kcov exposes kernel PCs and control flow to user-space which is insecure. But debugfs should not be mapped as user accessible. Based on a patch by Quentin Casasnovas. [akpm@linux-foundation.org: make task_struct.kcov_mode have type `enum kcov_mode'] [akpm@linux-foundation.org: unbreak allmodconfig] [akpm@linux-foundation.org: follow x86 Makefile layout standards] Signed-off-by: Dmitry Vyukov Reviewed-by: Kees Cook Cc: syzkaller Cc: Vegard Nossum Cc: Catalin Marinas Cc: Tavis Ormandy Cc: Will Deacon Cc: Quentin Casasnovas Cc: Kostya Serebryany Cc: Eric Dumazet Cc: Alexander Potapenko Cc: Kees Cook Cc: Bjorn Helgaas Cc: Sasha Levin Cc: David Drysdale Cc: Ard Biesheuvel Cc: Andrey Ryabinin Cc: Kirill A. Shutemov Cc: Jiri Slaby Cc: Ingo Molnar Cc: Thomas Gleixner Cc: "H. Peter Anvin" Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

x86, irq: Move HT IRQ related code from io_apic.c into htirq.c

2014-12-16T13:08:17Z

Create arch/x86/kernel/apic/htirq.c to host Hypertransport IRQ related code, preparing for enabling hierarchy irqdomain. Signed-off-by: Jiang Liu Cc: Konrad Rzeszutek Wilk Cc: Tony Luck Cc: Joerg Roedel Cc: Greg Kroah-Hartman Cc: Benjamin Herrenschmidt Cc: Rafael J. Wysocki Cc: Bjorn Helgaas Cc: Randy Dunlap Cc: Yinghai Lu Cc: Borislav Petkov Cc: Grant Likely Cc: Prarit Bhargava Link: http://lkml.kernel.org/r/1414397531-28254-13-git-send-email-jiang.liu@linux.intel.com Signed-off-by: Thomas Gleixner

x86, irq: Move PCI MSI related code from io_apic.c into msi.c

2014-12-16T13:08:17Z

Create arch/x86/kernel/apic/msi.c to host MSI related code, preparing for enabling hierarchy irqdomain. Signed-off-by: Jiang Liu Cc: Konrad Rzeszutek Wilk Cc: Tony Luck Cc: Joerg Roedel Cc: Greg Kroah-Hartman Cc: Benjamin Herrenschmidt Cc: Rafael J. Wysocki Cc: Bjorn Helgaas Cc: Randy Dunlap Cc: Yinghai Lu Cc: Borislav Petkov Cc: Rafael J. Wysocki Cc: Grant Likely Cc: Prarit Bhargava Link: http://lkml.kernel.org/r/1414397531-28254-12-git-send-email-jiang.liu@linux.intel.com Signed-off-by: Thomas Gleixner

x86, irq: Move local APIC related code from io_apic.c into vector.c

2014-12-16T13:08:16Z

Create arch/x86/kernel/apic/vector.c to host local APIC related code, prepare for making MSI/HT_IRQ independent of IOAPIC. Signed-off-by: Jiang Liu Cc: Konrad Rzeszutek Wilk Cc: Tony Luck Cc: Joerg Roedel Cc: Greg Kroah-Hartman Cc: Benjamin Herrenschmidt Cc: Rafael J. Wysocki Cc: Bjorn Helgaas Cc: Randy Dunlap Cc: Yinghai Lu Cc: Borislav Petkov Cc: Prarit Bhargava Cc: Grant Likely Link: http://lkml.kernel.org/r/1414397531-28254-10-git-send-email-jiang.liu@linux.intel.com Signed-off-by: Thomas Gleixner

x86, platforms: Remove NUMAQ

2014-02-27T16:07:39Z

The NUMAQ support seems to be unmaintained, remove it. Cc: Paul Gortmaker Cc: David Rientjes Acked-by: Paul E. McKenney Signed-off-by: H. Peter Anvin Link: http://lkml.kernel.org/r/n/530CFD6C.7040705@zytor.com

x86, apic: Remove support for IBM Summit/EXA chipset

2014-02-12T02:11:13Z

There should no longer be any IBM x440 systems or those using the Summit/EXA chipset out in the wild, so remove support for it. We've done our due diligence in reaching out to any contact information listed for this chipset and no indication was given that it should be kept around. Signed-off-by: David Rientjes

x86, apic: Remove support for ia32-based Unisys ES7000

2014-02-12T01:47:48Z

There should no longer be any ia32-based Unisys ES7000 systems out in the wild, so remove support for it. We've done our due diligence in reaching out to any contact information listed for this system and no indication was given that it should be kept around. Signed-off-by: David Rientjes

x86: Add NumaChip support

2011-12-05T16:17:24Z

Adds support for Numascale NumaChip large-SMP systems. It is needed to enable the booting of more than ~168 cores. v2: - [Steffen] enumerate only accessible northbridges - [Daniel] rediffed and validated against 3.1-rc10 v3: - [Daniel] use x86_init core numbering override - [Daniel] cleanups as per feedback v4: - [Daniel] use updated x86_cpuinit override v5: - drop disabling interrupts locally, as ISR write is atomic; drop delay - added read-mostly annotations where appropriate - require CONFIG_SMP, so drop conditional path Workload tested on 96 cores/16 sockets. Signed-off-by: Steffen Persvold Signed-off-by: Daniel J Blueman Cc: Jesse Barnes Link: http://lkml.kernel.org/r/1323101246-2400-1-git-send-email-daniel@numascale-asia.com Signed-off-by: Ingo Molnar

x86, apic: Introduce .apicdrivers section to find the list of apic drivers

2011-05-22T09:48:03Z

This will pave the way for each apic driver to be self-contained and eliminate the need for apic_probe[]. Order in which apic drivers are listed in the .apicdrivers section is important, as this determines the apic probe order. And this is enforced by the ordering of apic driver files in the Makefile and the macros apic_driver()/apic_drivers(). Signed-off-by: Suresh Siddha Tested-by: Cyrill Gorcunov Cc: steiner@sgi.com Cc: gorcunov@openvz.org Cc: yinghai@kernel.org Link: http://lkml.kernel.org/r/20110521005526.068775085@sbsiddha-MOBL3.sc.intel.com Signed-off-by: Ingo Molnar

x86, nmi_watchdog: Remove the old nmi_watchdog

2010-11-18T08:08:23Z

Now that we have a new nmi_watchdog that is more generic and sits on top of the perf subsystem, we really do not need the old nmi_watchdog any more. In addition, the old nmi_watchdog doesn't really work if you are using the default clocksource, hpet. The old nmi_watchdog code relied on local apic interrupts to determine if the cpu is still alive. With hpet as the clocksource, these interrupts don't increment any more and the old nmi_watchdog triggers false postives. This piece removes the old nmi_watchdog code and stubs out any variables and functions calls. The stubs are the same ones used by the new nmi_watchdog code, so it should be well tested. Signed-off-by: Don Zickus Cc: fweisbec@gmail.com Cc: gorcunov@openvz.org LKML-Reference: <1289578944-28564-2-git-send-email-dzickus@redhat.com> Signed-off-by: Ingo Molnar