Hi Alan,
On 3/18/19 2:57 PM, Alan Cox wrote:
>> I think the compressed tarball is much simpler/easier overall. If
>> someone really wants the filesystem, they just uncompress it into a
>> tmpfs mount. It's much less moving kernel code to worry about.
>
> There is an even simpler approach. The people who want this for whatever
> strange reason are Android folks. Android lives on flash, so all they have
> to do is put the headers in a flash file system that is updated with the
> kernel and mount it wherever they like. Simple matter of a bit of
> devicetree no ?
The Android use-case scenario might indeed have been the one to best
crystallize the requirement, but that doesn't mean that all use-cases of
eBPF wouldn't benefit from this -- which in fact they would, see
instructions here for example on the need for kernel headers:
https://github.com/iovisor/bcc/blob/master/INSTALL.md
Just a quick $PREFERRED_SEARCH_ENGINE search returns interesting
exchanges such as this one taken from a discussion thread on LWN
covering an introduction to eBPF:
https://lwn.net/Articles/741348/
Effectively this person had to be hand-held in understanding that they
needed a good set of kernel headers to make the tool work. Their comment
after being shown that this was needed was:
"It looks like the headers package you need on Ubuntu is
linux-headers-$(uname -r), which contains the entire kernel source tree,
and is specific to the running kernel."
Surely having Joel's patch in the kernel would obviate the issue for all
Linux kernel users, not just Android.
Cheers,
--
Karim Yaghmour
CEO - Opersys inc. / www.opersys.comhttp://twitter.com/karimyaghmour
If the cgroup destruction races with an exit() of a belonging
process(es), cg_kill_all() may fail. It's not a good reason to make
cg_destroy() fail and leave the cgroup in place, potentially causing
next test runs to fail.
Signed-off-by: Roman Gushchin <guro(a)fb.com>
Cc: Shuah Khan <shuah(a)kernel.org>
Cc: Tejun Heo <tj(a)kernel.org>
Cc: kernel-team(a)fb.com
Cc: linux-kselftest(a)vger.kernel.org
---
tools/testing/selftests/cgroup/cgroup_util.c | 4 +---
1 file changed, 1 insertion(+), 3 deletions(-)
diff --git a/tools/testing/selftests/cgroup/cgroup_util.c b/tools/testing/selftests/cgroup/cgroup_util.c
index 14c9fe284806..eba06f94433b 100644
--- a/tools/testing/selftests/cgroup/cgroup_util.c
+++ b/tools/testing/selftests/cgroup/cgroup_util.c
@@ -227,9 +227,7 @@ int cg_destroy(const char *cgroup)
retry:
ret = rmdir(cgroup);
if (ret && errno == EBUSY) {
- ret = cg_killall(cgroup);
- if (ret)
- return ret;
+ cg_killall(cgroup);
usleep(100);
goto retry;
}
--
2.20.1
Introduce in-kernel headers and other artifacts which are made available
as an archive through proc (/proc/kheaders.tar.xz file). This archive makes
it possible to build kernel modules, run eBPF programs, and other
tracing programs that need to extend the kernel for tracing purposes
without any dependency on the file system having headers and build
artifacts.
On Android and embedded systems, it is common to switch kernels but not
have kernel headers available on the file system. Raw kernel headers
also cannot be copied into the filesystem like they can be on other
distros, due to licensing and other issues. There's no linux-headers
package on Android. Further once a different kernel is booted, any
headers stored on the file system will no longer be useful. By storing
the headers as a compressed archive within the kernel, we can avoid these
issues that have been a hindrance for a long time.
The feature is also buildable as a module just in case the user desires
it not being part of the kernel image. This makes it possible to load
and unload the headers on demand. A tracing program, or a kernel module
builder can load the module, do its operations, and then unload the
module to save kernel memory. The total memory needed is 3.8MB.
The code to read the headers is based on /proc/config.gz code and uses
the same technique to embed the headers.
To build a module, the below steps have been tested on an x86 machine:
modprobe kheaders
rm -rf $HOME/headers
mkdir -p $HOME/headers
tar -xvf /proc/kheaders.tar.xz -C $HOME/headers >/dev/null
cd my-kernel-module
make -C $HOME/headers M=$(pwd) modules
rmmod kheaders
Additional notes:
(1) external modules must be built on the same arch as the host that
built vmlinux. This can be done either in a qemu emulated chroot on the
target, or natively. This is due to host arch dependency of kernel
scripts.
(2)
A limitation of module building with this is, since Module.symvers is
not available in the archive due to a cyclic dependency with building of
the archive into the kernel or module binaries, the modules built using
the archive will not contain symbol versioning (modversion). This is
usually not an issue since the idea of this patch is to build a kernel
module on the fly and load it into the same kernel. An appropriate
warning is already printed by the kernel to alert the user of modules
not having modversions when built using the archive. For building with
modversions, the user can use traditional header packages. For our
tracing usecases, we build modules on the fly with this so it is not a
concern.
(3) I have left IKHD_ST and IKHD_ED markers as is to facilitate
future patches that would extract the headers from a kernel or module
image.
Signed-off-by: Joel Fernandes (Google) <joel(a)joelfernandes.org>
---
Changes since v3:
- Blank tar was being generated because of a one line I
forgot to push. It is updated now.
- Added module.lds since arm64 needs it to build modules.
Changes since v2:
(Thanks to Masahiro Yamada for several excellent suggestions)
- Added support for out of tree builds.
- Added incremental build support bringing down build time of
incremental builds from 50 seconds to 5 seconds.
- Fixed various small nits / cleanups.
- clean ups to kheaders.c pointed by Alexey Dobriyan.
- Fixed MODULE_LICENSE in test module and kheaders.c
- Dropped Module.symvers from archive due to circular dependency.
Changes since v1:
- removed IKH_EXTRA variable, not needed (Masahiro Yamada)
- small fix ups to selftest
- added target to main Makefile etc
- added MODULE_LICENSE to test module
- made selftest more quiet
Changes since RFC:
Both changes bring size down to 3.8MB:
- use xz for compression
- strip comments except SPDX lines
- Call out the module name in Kconfig
- Also added selftests in second patch to ensure headers are always
working.
Other notes:
By the way I still see this error (without the patch) when doing a clean
build: Makefile:594: include/config/auto.conf: No such file or directory
It appears to be because of commit 0a16d2e8cb7e ("kbuild: use 'include'
directive to load auto.conf from top Makefile")
Documentation/dontdiff | 1 +
init/Kconfig | 11 ++++++
kernel/.gitignore | 3 ++
kernel/Makefile | 37 +++++++++++++++++++
kernel/kheaders.c | 72 ++++++++++++++++++++++++++++++++++++
scripts/gen_ikh_data.sh | 78 +++++++++++++++++++++++++++++++++++++++
scripts/strip-comments.pl | 8 ++++
7 files changed, 210 insertions(+)
create mode 100644 kernel/kheaders.c
create mode 100755 scripts/gen_ikh_data.sh
create mode 100755 scripts/strip-comments.pl
diff --git a/Documentation/dontdiff b/Documentation/dontdiff
index 2228fcc8e29f..05a2319ee2a2 100644
--- a/Documentation/dontdiff
+++ b/Documentation/dontdiff
@@ -151,6 +151,7 @@ int8.c
kallsyms
kconfig
keywords.c
+kheaders_data.h*
ksym.c*
ksym.h*
kxgettext
diff --git a/init/Kconfig b/init/Kconfig
index c9386a365eea..63ff0990ae55 100644
--- a/init/Kconfig
+++ b/init/Kconfig
@@ -563,6 +563,17 @@ config IKCONFIG_PROC
This option enables access to the kernel configuration file
through /proc/config.gz.
+config IKHEADERS_PROC
+ tristate "Enable kernel header artifacts through /proc/kheaders.tar.xz"
+ select BUILD_BIN2C
+ depends on PROC_FS
+ help
+ This option enables access to the kernel header and other artifacts that
+ are generated during the build process. These can be used to build kernel
+ modules, and other in-kernel programs such as those generated by eBPF
+ and systemtap tools. If you build the headers as a module, a module
+ called kheaders.ko is built which can be loaded to get access to them.
+
config LOG_BUF_SHIFT
int "Kernel log buffer size (16 => 64KB, 17 => 128KB)"
range 12 25
diff --git a/kernel/.gitignore b/kernel/.gitignore
index b3097bde4e9c..484018945e93 100644
--- a/kernel/.gitignore
+++ b/kernel/.gitignore
@@ -3,5 +3,8 @@
#
config_data.h
config_data.gz
+kheaders.md5
+kheaders_data.h
+kheaders_data.tar.xz
timeconst.h
hz.bc
diff --git a/kernel/Makefile b/kernel/Makefile
index 6aa7543bcdb2..240685a6b638 100644
--- a/kernel/Makefile
+++ b/kernel/Makefile
@@ -70,6 +70,7 @@ obj-$(CONFIG_UTS_NS) += utsname.o
obj-$(CONFIG_USER_NS) += user_namespace.o
obj-$(CONFIG_PID_NS) += pid_namespace.o
obj-$(CONFIG_IKCONFIG) += configs.o
+obj-$(CONFIG_IKHEADERS_PROC) += kheaders.o
obj-$(CONFIG_SMP) += stop_machine.o
obj-$(CONFIG_KPROBES_SANITY_TEST) += test_kprobes.o
obj-$(CONFIG_AUDIT) += audit.o auditfilter.o
@@ -130,3 +131,39 @@ filechk_ikconfiggz = \
targets += config_data.h
$(obj)/config_data.h: $(obj)/config_data.gz FORCE
$(call filechk,ikconfiggz)
+
+# Build a list of in-kernel headers for building kernel modules
+ikh_file_list := include/
+ikh_file_list += arch/$(SRCARCH)/Makefile
+ikh_file_list += arch/$(SRCARCH)/include/
+ikh_file_list += arch/$(SRCARCH)/kernel/module.lds
+ikh_file_list += scripts/
+ikh_file_list += Makefile
+
+# Things we need from the $objtree. "OBJDIR" is for the gen_ikh_data.sh
+# script to identify that this comes from the $objtree directory
+ikh_file_list += OBJDIR/scripts/
+ikh_file_list += OBJDIR/include/
+ikh_file_list += OBJDIR/arch/$(SRCARCH)/include/
+ifeq ($(CONFIG_STACK_VALIDATION), y)
+ikh_file_list += OBJDIR/tools/objtool/objtool
+endif
+
+$(obj)/kheaders.o: $(obj)/kheaders_data.h
+
+targets += kheaders_data.tar.xz
+
+quiet_cmd_genikh = GEN $(obj)/kheaders_data.tar.xz
+cmd_genikh = $(srctree)/scripts/gen_ikh_data.sh $@ $(ikh_file_list)
+$(obj)/kheaders_data.tar.xz: FORCE
+ $(call cmd,genikh)
+
+filechk_ikheadersxz = \
+ echo "static const char kernel_headers_data[] __used = KH_MAGIC_START"; \
+ cat $< | scripts/bin2c; \
+ echo "KH_MAGIC_END;"
+
+targets += kheaders_data.h
+targets += kheaders.md5
+$(obj)/kheaders_data.h: $(obj)/kheaders_data.tar.xz FORCE
+ $(call filechk,ikheadersxz)
diff --git a/kernel/kheaders.c b/kernel/kheaders.c
new file mode 100644
index 000000000000..46a6358301e5
--- /dev/null
+++ b/kernel/kheaders.c
@@ -0,0 +1,72 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * kernel/kheaders.c
+ * Provide headers and artifacts needed to build kernel modules.
+ * (Borrowed code from kernel/configs.c)
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/proc_fs.h>
+#include <linux/init.h>
+#include <linux/uaccess.h>
+
+/*
+ * Define kernel_headers_data and kernel_headers_data_size, which contains the
+ * compressed kernel headers. The file is first compressed with xz and then
+ * bounded by two eight byte magic numbers to allow extraction from a binary
+ * kernel image:
+ *
+ * IKHD_ST
+ * <image>
+ * IKHD_ED
+ */
+#define KH_MAGIC_START "IKHD_ST"
+#define KH_MAGIC_END "IKHD_ED"
+#include "kheaders_data.h"
+
+
+#define KH_MAGIC_SIZE (sizeof(KH_MAGIC_START) - 1)
+#define kernel_headers_data_size \
+ (sizeof(kernel_headers_data) - 1 - KH_MAGIC_SIZE * 2)
+
+static ssize_t
+ikheaders_read_current(struct file *file, char __user *buf,
+ size_t len, loff_t *offset)
+{
+ return simple_read_from_buffer(buf, len, offset,
+ kernel_headers_data + KH_MAGIC_SIZE,
+ kernel_headers_data_size);
+}
+
+static const struct file_operations ikheaders_file_ops = {
+ .read = ikheaders_read_current,
+ .llseek = default_llseek,
+};
+
+static int __init ikheaders_init(void)
+{
+ struct proc_dir_entry *entry;
+
+ /* create the current headers file */
+ entry = proc_create("kheaders.tar.xz", S_IRUGO, NULL,
+ &ikheaders_file_ops);
+ if (!entry)
+ return -ENOMEM;
+
+ proc_set_size(entry, kernel_headers_data_size);
+
+ return 0;
+}
+
+static void __exit ikheaders_cleanup(void)
+{
+ remove_proc_entry("kheaders.tar.xz", NULL);
+}
+
+module_init(ikheaders_init);
+module_exit(ikheaders_cleanup);
+
+MODULE_LICENSE("GPL v2");
+MODULE_AUTHOR("Joel Fernandes");
+MODULE_DESCRIPTION("Echo the kernel header artifacts used to build the kernel");
diff --git a/scripts/gen_ikh_data.sh b/scripts/gen_ikh_data.sh
new file mode 100755
index 000000000000..1fa5628fcc30
--- /dev/null
+++ b/scripts/gen_ikh_data.sh
@@ -0,0 +1,78 @@
+#!/bin/bash
+# SPDX-License-Identifier: GPL-2.0
+
+spath="$(dirname "$(readlink -f "$0")")"
+kroot="$spath/.."
+outdir="$(pwd)"
+tarfile=$1
+cpio_dir=$outdir/$tarfile.tmp
+
+file_list=${@:2}
+
+src_file_list=""
+for f in $file_list; do
+ src_file_list="$src_file_list $(echo $f | grep -v OBJDIR)"
+done
+
+obj_file_list=""
+for f in $file_list; do
+ f=$(echo $f | grep OBJDIR | sed -e 's/OBJDIR\///g')
+ obj_file_list="$obj_file_list $f";
+done
+
+# Support incremental builds by skipping archive generation
+# if timestamps of files being archived are not changed.
+
+# This block is useful for debugging the incremental builds.
+# Uncomment it for debugging.
+# iter=1
+# if [ ! -f /tmp/iter ]; then echo 1 > /tmp/iter;
+# else; iter=$(($(cat /tmp/iter) + 1)); fi
+# find $src_file_list -type f | xargs ls -lR > /tmp/src-ls-$iter
+# find $obj_file_list -type f | xargs ls -lR > /tmp/obj-ls-$iter
+
+# modules.order and include/generated/compile.h are ignored because these are
+# touched even when none of the source files changed. This causes pointless
+# regeneration, so let us ignore them for md5 calculation.
+pushd $kroot > /dev/null
+src_files_md5="$(find $src_file_list -type f ! -name modules.order |
+ grep -v "include/generated/compile.h" |
+ xargs ls -lR | md5sum | cut -d ' ' -f1)"
+popd > /dev/null
+obj_files_md5="$(find $obj_file_list -type f ! -name modules.order |
+ grep -v "include/generated/compile.h" |
+ xargs ls -lR | md5sum | cut -d ' ' -f1)"
+
+if [ -f $tarfile ]; then tarfile_md5="$(md5sum $tarfile | cut -d ' ' -f1)"; fi
+if [ -f kernel/kheaders.md5 ] &&
+ [ "$(cat kernel/kheaders.md5|head -1)" == "$src_files_md5" ] &&
+ [ "$(cat kernel/kheaders.md5|head -2|tail -1)" == "$obj_files_md5" ] &&
+ [ "$(cat kernel/kheaders.md5|tail -1)" == "$tarfile_md5" ]; then
+ exit
+fi
+
+rm -rf $cpio_dir
+mkdir $cpio_dir
+
+pushd $kroot > /dev/null
+for f in $src_file_list;
+ do find "$f" ! -name "*.c" ! -name "*.o" ! -name "*.cmd" ! -name ".*";
+done | cpio --quiet -pd $cpio_dir
+popd > /dev/null
+
+# The second CPIO can complain if files already exist which can
+# happen with out of tree builds. Just silence CPIO for now.
+for f in $obj_file_list;
+ do find "$f" ! -name "*.c" ! -name "*.o" ! -name "*.cmd" ! -name ".*";
+done | cpio --quiet -pd $cpio_dir >/dev/null 2>&1
+
+find $cpio_dir -type f -print0 |
+ xargs -0 -P8 -n1 -I {} sh -c "$spath/strip-comments.pl {}"
+
+tar -Jcf $tarfile -C $cpio_dir/ . > /dev/null
+
+echo "$src_files_md5" > kernel/kheaders.md5
+echo "$obj_files_md5" >> kernel/kheaders.md5
+echo "$(md5sum $tarfile | cut -d ' ' -f1)" >> kernel/kheaders.md5
+
+rm -rf $cpio_dir
diff --git a/scripts/strip-comments.pl b/scripts/strip-comments.pl
new file mode 100755
index 000000000000..f8ada87c5802
--- /dev/null
+++ b/scripts/strip-comments.pl
@@ -0,0 +1,8 @@
+#!/usr/bin/perl -pi
+# SPDX-License-Identifier: GPL-2.0
+
+# This script removes /**/ comments from a file, unless such comments
+# contain "SPDX". It is used when building compressed in-kernel headers.
+
+BEGIN {undef $/;}
+s/\/\*((?!SPDX).)*?\*\///smg;
--
2.21.0.352.gf09ad66450-goog
The kernel may be configured or an IMA policy specified on the boot
command line requiring the kexec kernel image signature to be verified.
At runtime a custom IMA policy may be loaded, replacing the policy
specified on the boot command line. In addition, the arch specific
policy rules are dynamically defined based on the secure boot mode that
may require the kernel image signature to be verified.
The kernel image may have a PE signature, an IMA signature, or both. In
addition, there are two kexec syscalls - kexec_load and kexec_file_load
- but only the kexec_file_load syscall can verify signatures.
These kexec selftests verify that only properly signed kernel images are
loaded as required, based on the kernel config, the secure boot mode,
and the IMA runtime policy.
Loading a kernel image or kernel module requires root privileges. To
run just the KEXEC selftests: sudo make TARGETS=kexec kselftest
Changelog v4:
- Moved the kexec tests to selftests/kexec, as requested by Dave Young.
- Removed the kernel module selftest from this patch set.
- Rewritten cover letter, removing reference to kernel modules.
Changelog v3:
- Updated tests based on Petr's review, including the defining a common
test to check for root privileges.
- Modified config, removing the CONFIG_KEXEC_VERIFY_SIG requirement.
- Updated the SPDX license to GPL-2.0 based on Shuah's review.
- Updated the secureboot mode test to check the SetupMode as well, based
on David Young's review.
Mimi Zohar (7):
selftests/kexec: move the IMA kexec_load selftest to selftests/kexec
selftests/kexec: cleanup the kexec selftest
selftests/kexec: define a set of common functions
selftests/kexec: define common logging functions
kselftest/kexec: define "require_root_privileges"
selftests/kexec: kexec_file_load syscall test
selftests/kexec: check kexec_load and kexec_file_load are enabled
Petr Vorel (1):
selftests/kexec: Add missing '=y' to config options
tools/testing/selftests/Makefile | 2 +-
tools/testing/selftests/ima/Makefile | 11 --
tools/testing/selftests/ima/config | 4 -
tools/testing/selftests/ima/test_kexec_load.sh | 54 ------
tools/testing/selftests/kexec/Makefile | 12 ++
tools/testing/selftests/kexec/config | 3 +
tools/testing/selftests/kexec/kexec_common_lib.sh | 175 ++++++++++++++++++
.../selftests/kexec/test_kexec_file_load.sh | 195 +++++++++++++++++++++
tools/testing/selftests/kexec/test_kexec_load.sh | 39 +++++
9 files changed, 425 insertions(+), 70 deletions(-)
delete mode 100644 tools/testing/selftests/ima/Makefile
delete mode 100644 tools/testing/selftests/ima/config
delete mode 100755 tools/testing/selftests/ima/test_kexec_load.sh
create mode 100644 tools/testing/selftests/kexec/Makefile
create mode 100644 tools/testing/selftests/kexec/config
create mode 100755 tools/testing/selftests/kexec/kexec_common_lib.sh
create mode 100755 tools/testing/selftests/kexec/test_kexec_file_load.sh
create mode 100755 tools/testing/selftests/kexec/test_kexec_load.sh
--
2.7.5
Atom-based CPUs trigger stack fault when invoke 32-bit SYSENTER instruction
with invalid register values. So we also need SIGBUS handling in this case.
Following is assembly when the fault exception happens.
(gdb) disassemble $eip
Dump of assembler code for function __kernel_vsyscall:
0xf7fd8fe0 <+0>: push %ecx
0xf7fd8fe1 <+1>: push %edx
0xf7fd8fe2 <+2>: push %ebp
0xf7fd8fe3 <+3>: mov %esp,%ebp
0xf7fd8fe5 <+5>: sysenter
0xf7fd8fe7 <+7>: int $0x80
=> 0xf7fd8fe9 <+9>: pop %ebp
0xf7fd8fea <+10>: pop %edx
0xf7fd8feb <+11>: pop %ecx
0xf7fd8fec <+12>: ret
End of assembler dump.
According to Intel SDM, this could also be a Stack Segment Fault(#SS, 12),
except a normal Page Fault(#PF, 14). Especially, in section 6.9 of Vol.3A,
both stack and page faults are within the 10th(lowest priority) class, and
as it said, "exceptions within each class are implementation-dependent and
may vary from processor to processor". It's expected for processors like
Intel Atom to trigger stack fault(SIGBUS), while we get page fault(SIGSEGV)
from common Core processors.
Signed-off-by: Tong Bo <bo.tong(a)intel.com>
---
tools/testing/selftests/x86/syscall_arg_fault.c | 9 +++++++--
1 file changed, 7 insertions(+), 2 deletions(-)
diff --git a/tools/testing/selftests/x86/syscall_arg_fault.c b/tools/testing/selftests/x86/syscall_arg_fault.c
index 7db4fc9..810180a 100644
--- a/tools/testing/selftests/x86/syscall_arg_fault.c
+++ b/tools/testing/selftests/x86/syscall_arg_fault.c
@@ -43,7 +43,7 @@ static sigjmp_buf jmpbuf;
static volatile sig_atomic_t n_errs;
-static void sigsegv(int sig, siginfo_t *info, void *ctx_void)
+static void sigsegv_or_sigbus(int sig, siginfo_t *info, void *ctx_void)
{
ucontext_t *ctx = (ucontext_t*)ctx_void;
@@ -73,7 +73,12 @@ int main()
if (sigaltstack(&stack, NULL) != 0)
err(1, "sigaltstack");
- sethandler(SIGSEGV, sigsegv, SA_ONSTACK);
+ sethandler(SIGSEGV, sigsegv_or_sigbus, SA_ONSTACK);
+ /* The actual exception can vary. On Atom CPUs, we get #SS
+ * instead of #PF when the vDSO fails to access the stack when
+ * ESP is too close to 2^32, and #SS causes SIGBUS.
+ */
+ sethandler(SIGBUS, sigsegv_or_sigbus, SA_ONSTACK);
sethandler(SIGILL, sigill, SA_ONSTACK);
/*
--
2.7.4
The entries within __rseq_table are aligned on 32 bytes due to
linux/rseq.h struct rseq_cs uapi requirements, but the start of the
__rseq_table section is not guaranteed to be 32-byte aligned. It can
cause padding to be added at the start of the section, which makes it
hard to use as an array of items by debuggers.
Considering that __rseq_table does not really consist of a table due to
the presence of padding, rename this section to __rseq_cs.
Create a new __rseq_cs_ptr_array section which contains 64-bit packed
pointers to entries within the __rseq_cs section.
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers(a)efficios.com>
CC: Thomas Gleixner <tglx(a)linutronix.de>
CC: Joel Fernandes <joelaf(a)google.com>
CC: Peter Zijlstra <peterz(a)infradead.org>
CC: Catalin Marinas <catalin.marinas(a)arm.com>
CC: Dave Watson <davejwatson(a)fb.com>
CC: Will Deacon <will.deacon(a)arm.com>
CC: Shuah Khan <shuah(a)kernel.org>
CC: Andi Kleen <andi(a)firstfloor.org>
CC: linux-kselftest(a)vger.kernel.org
CC: "H . Peter Anvin" <hpa(a)zytor.com>
CC: Chris Lameter <cl(a)linux.com>
CC: Russell King <linux(a)arm.linux.org.uk>
CC: Michael Kerrisk <mtk.manpages(a)gmail.com>
CC: "Paul E . McKenney" <paulmck(a)linux.vnet.ibm.com>
CC: Paul Turner <pjt(a)google.com>
CC: Boqun Feng <boqun.feng(a)gmail.com>
CC: Josh Triplett <josh(a)joshtriplett.org>
CC: Steven Rostedt <rostedt(a)goodmis.org>
CC: Ben Maurer <bmaurer(a)fb.com>
CC: linux-api(a)vger.kernel.org
CC: Andy Lutomirski <luto(a)amacapital.net>
CC: Andrew Morton <akpm(a)linux-foundation.org>
CC: Linus Torvalds <torvalds(a)linux-foundation.org>
---
tools/testing/selftests/rseq/rseq-arm.h | 32 +++++++++++++++++--------------
tools/testing/selftests/rseq/rseq-arm64.h | 9 ++++++---
tools/testing/selftests/rseq/rseq-mips.h | 32 +++++++++++++++++--------------
tools/testing/selftests/rseq/rseq-ppc.h | 22 +++++++++++++--------
tools/testing/selftests/rseq/rseq-s390.h | 18 +++++++++++------
tools/testing/selftests/rseq/rseq-x86.h | 19 ++++++++++++------
6 files changed, 81 insertions(+), 51 deletions(-)
diff --git a/tools/testing/selftests/rseq/rseq-arm.h b/tools/testing/selftests/rseq/rseq-arm.h
index 17e8d231943a..5f262c54364f 100644
--- a/tools/testing/selftests/rseq/rseq-arm.h
+++ b/tools/testing/selftests/rseq/rseq-arm.h
@@ -30,24 +30,28 @@ do { \
#include "rseq-skip.h"
#else /* !RSEQ_SKIP_FASTPATH */
-#define __RSEQ_ASM_DEFINE_TABLE(version, flags, start_ip, \
+#define __RSEQ_ASM_DEFINE_TABLE(label, version, flags, start_ip, \
post_commit_offset, abort_ip) \
- ".pushsection __rseq_table, \"aw\"\n\t" \
+ ".pushsection __rseq_cs, \"aw\"\n\t" \
".balign 32\n\t" \
+ __rseq_str(label) ":\n\t" \
".word " __rseq_str(version) ", " __rseq_str(flags) "\n\t" \
".word " __rseq_str(start_ip) ", 0x0, " __rseq_str(post_commit_offset) ", 0x0, " __rseq_str(abort_ip) ", 0x0\n\t" \
+ ".popsection\n\t" \
+ ".pushsection __rseq_cs_ptr_array, \"aw\"\n\t" \
+ ".word " __rseq_str(label) "b, 0x0\n\t" \
".popsection\n\t"
-#define RSEQ_ASM_DEFINE_TABLE(start_ip, post_commit_ip, abort_ip) \
- __RSEQ_ASM_DEFINE_TABLE(0x0, 0x0, start_ip, \
+#define RSEQ_ASM_DEFINE_TABLE(label, start_ip, post_commit_ip, abort_ip) \
+ __RSEQ_ASM_DEFINE_TABLE(label, 0x0, 0x0, start_ip, \
(post_commit_ip - start_ip), abort_ip)
/*
* Exit points of a rseq critical section consist of all instructions outside
* of the critical section where a critical section can either branch to or
* reach through the normal course of its execution. The abort IP and the
- * post-commit IP are already part of the __rseq_table section and should not
- * be explicitly defined as additional exit points. Knowing all exit points is
+ * post-commit IP are already part of the __rseq_cs section and should not be
+ * explicitly defined as additional exit points. Knowing all exit points is
* useful to assist debuggers stepping over the critical section.
*/
#define RSEQ_ASM_DEFINE_EXIT_POINT(start_ip, exit_ip) \
@@ -99,7 +103,7 @@ int rseq_cmpeqv_storev(intptr_t *v, intptr_t expect, intptr_t newv, int cpu)
rseq_workaround_gcc_asm_size_guess();
__asm__ __volatile__ goto (
- RSEQ_ASM_DEFINE_TABLE(1f, 2f, 4f) /* start, commit, abort */
+ RSEQ_ASM_DEFINE_TABLE(9, 1f, 2f, 4f) /* start, commit, abort */
RSEQ_ASM_DEFINE_EXIT_POINT(1f, %l[cmpfail])
#ifdef RSEQ_COMPARE_TWICE
RSEQ_ASM_DEFINE_EXIT_POINT(1f, %l[error1])
@@ -166,7 +170,7 @@ int rseq_cmpnev_storeoffp_load(intptr_t *v, intptr_t expectnot,
rseq_workaround_gcc_asm_size_guess();
__asm__ __volatile__ goto (
- RSEQ_ASM_DEFINE_TABLE(1f, 2f, 4f) /* start, commit, abort */
+ RSEQ_ASM_DEFINE_TABLE(9, 1f, 2f, 4f) /* start, commit, abort */
RSEQ_ASM_DEFINE_EXIT_POINT(1f, %l[cmpfail])
#ifdef RSEQ_COMPARE_TWICE
RSEQ_ASM_DEFINE_EXIT_POINT(1f, %l[error1])
@@ -237,7 +241,7 @@ int rseq_addv(intptr_t *v, intptr_t count, int cpu)
rseq_workaround_gcc_asm_size_guess();
__asm__ __volatile__ goto (
- RSEQ_ASM_DEFINE_TABLE(1f, 2f, 4f) /* start, commit, abort */
+ RSEQ_ASM_DEFINE_TABLE(9, 1f, 2f, 4f) /* start, commit, abort */
#ifdef RSEQ_COMPARE_TWICE
RSEQ_ASM_DEFINE_EXIT_POINT(1f, %l[error1])
#endif
@@ -292,7 +296,7 @@ int rseq_cmpeqv_trystorev_storev(intptr_t *v, intptr_t expect,
rseq_workaround_gcc_asm_size_guess();
__asm__ __volatile__ goto (
- RSEQ_ASM_DEFINE_TABLE(1f, 2f, 4f) /* start, commit, abort */
+ RSEQ_ASM_DEFINE_TABLE(9, 1f, 2f, 4f) /* start, commit, abort */
RSEQ_ASM_DEFINE_EXIT_POINT(1f, %l[cmpfail])
#ifdef RSEQ_COMPARE_TWICE
RSEQ_ASM_DEFINE_EXIT_POINT(1f, %l[error1])
@@ -367,7 +371,7 @@ int rseq_cmpeqv_trystorev_storev_release(intptr_t *v, intptr_t expect,
rseq_workaround_gcc_asm_size_guess();
__asm__ __volatile__ goto (
- RSEQ_ASM_DEFINE_TABLE(1f, 2f, 4f) /* start, commit, abort */
+ RSEQ_ASM_DEFINE_TABLE(9, 1f, 2f, 4f) /* start, commit, abort */
RSEQ_ASM_DEFINE_EXIT_POINT(1f, %l[cmpfail])
#ifdef RSEQ_COMPARE_TWICE
RSEQ_ASM_DEFINE_EXIT_POINT(1f, %l[error1])
@@ -443,7 +447,7 @@ int rseq_cmpeqv_cmpeqv_storev(intptr_t *v, intptr_t expect,
rseq_workaround_gcc_asm_size_guess();
__asm__ __volatile__ goto (
- RSEQ_ASM_DEFINE_TABLE(1f, 2f, 4f) /* start, commit, abort */
+ RSEQ_ASM_DEFINE_TABLE(9, 1f, 2f, 4f) /* start, commit, abort */
RSEQ_ASM_DEFINE_EXIT_POINT(1f, %l[cmpfail])
#ifdef RSEQ_COMPARE_TWICE
RSEQ_ASM_DEFINE_EXIT_POINT(1f, %l[error1])
@@ -527,7 +531,7 @@ int rseq_cmpeqv_trymemcpy_storev(intptr_t *v, intptr_t expect,
rseq_workaround_gcc_asm_size_guess();
__asm__ __volatile__ goto (
- RSEQ_ASM_DEFINE_TABLE(1f, 2f, 4f) /* start, commit, abort */
+ RSEQ_ASM_DEFINE_TABLE(9, 1f, 2f, 4f) /* start, commit, abort */
RSEQ_ASM_DEFINE_EXIT_POINT(1f, %l[cmpfail])
#ifdef RSEQ_COMPARE_TWICE
RSEQ_ASM_DEFINE_EXIT_POINT(1f, %l[error1])
@@ -651,7 +655,7 @@ int rseq_cmpeqv_trymemcpy_storev_release(intptr_t *v, intptr_t expect,
rseq_workaround_gcc_asm_size_guess();
__asm__ __volatile__ goto (
- RSEQ_ASM_DEFINE_TABLE(1f, 2f, 4f) /* start, commit, abort */
+ RSEQ_ASM_DEFINE_TABLE(9, 1f, 2f, 4f) /* start, commit, abort */
RSEQ_ASM_DEFINE_EXIT_POINT(1f, %l[cmpfail])
#ifdef RSEQ_COMPARE_TWICE
RSEQ_ASM_DEFINE_EXIT_POINT(1f, %l[error1])
diff --git a/tools/testing/selftests/rseq/rseq-arm64.h b/tools/testing/selftests/rseq/rseq-arm64.h
index 2079f71e0ca2..b41a2a48e965 100644
--- a/tools/testing/selftests/rseq/rseq-arm64.h
+++ b/tools/testing/selftests/rseq/rseq-arm64.h
@@ -82,13 +82,16 @@ do { \
#define __RSEQ_ASM_DEFINE_TABLE(label, version, flags, start_ip, \
post_commit_offset, abort_ip) \
- " .pushsection __rseq_table, \"aw\"\n" \
+ " .pushsection __rseq_cs, \"aw\"\n" \
" .balign 32\n" \
__rseq_str(label) ":\n" \
" .long " __rseq_str(version) ", " __rseq_str(flags) "\n" \
" .quad " __rseq_str(start_ip) ", " \
__rseq_str(post_commit_offset) ", " \
__rseq_str(abort_ip) "\n" \
+ " .popsection\n\t" \
+ " .pushsection __rseq_cs_ptr_array, \"aw\"\n" \
+ " .quad " __rseq_str(label) "b\n" \
" .popsection\n"
#define RSEQ_ASM_DEFINE_TABLE(label, start_ip, post_commit_ip, abort_ip) \
@@ -99,8 +102,8 @@ do { \
* Exit points of a rseq critical section consist of all instructions outside
* of the critical section where a critical section can either branch to or
* reach through the normal course of its execution. The abort IP and the
- * post-commit IP are already part of the __rseq_table section and should not
- * be explicitly defined as additional exit points. Knowing all exit points is
+ * post-commit IP are already part of the __rseq_cs section and should not be
+ * explicitly defined as additional exit points. Knowing all exit points is
* useful to assist debuggers stepping over the critical section.
*/
#define RSEQ_ASM_DEFINE_EXIT_POINT(start_ip, exit_ip) \
diff --git a/tools/testing/selftests/rseq/rseq-mips.h b/tools/testing/selftests/rseq/rseq-mips.h
index 25d10ff54769..fe3eabcdcbe5 100644
--- a/tools/testing/selftests/rseq/rseq-mips.h
+++ b/tools/testing/selftests/rseq/rseq-mips.h
@@ -54,26 +54,30 @@ do { \
# error unsupported _MIPS_SZLONG
#endif
-#define __RSEQ_ASM_DEFINE_TABLE(version, flags, start_ip, \
+#define __RSEQ_ASM_DEFINE_TABLE(label, version, flags, start_ip, \
post_commit_offset, abort_ip) \
- ".pushsection __rseq_table, \"aw\"\n\t" \
+ ".pushsection __rseq_cs, \"aw\"\n\t" \
".balign 32\n\t" \
+ __rseq_str(label) ":\n\t" \
".word " __rseq_str(version) ", " __rseq_str(flags) "\n\t" \
LONG " " U32_U64_PAD(__rseq_str(start_ip)) "\n\t" \
LONG " " U32_U64_PAD(__rseq_str(post_commit_offset)) "\n\t" \
LONG " " U32_U64_PAD(__rseq_str(abort_ip)) "\n\t" \
+ ".popsection\n\t" \
+ ".pushsection __rseq_cs_ptr_array, \"aw\"\n\t" \
+ LONG " " U32_U64_PAD(__rseq_str(label) "b") "\n\t" \
".popsection\n\t"
-#define RSEQ_ASM_DEFINE_TABLE(start_ip, post_commit_ip, abort_ip) \
- __RSEQ_ASM_DEFINE_TABLE(0x0, 0x0, start_ip, \
+#define RSEQ_ASM_DEFINE_TABLE(label, start_ip, post_commit_ip, abort_ip) \
+ __RSEQ_ASM_DEFINE_TABLE(label, 0x0, 0x0, start_ip, \
(post_commit_ip - start_ip), abort_ip)
/*
* Exit points of a rseq critical section consist of all instructions outside
* of the critical section where a critical section can either branch to or
* reach through the normal course of its execution. The abort IP and the
- * post-commit IP are already part of the __rseq_table section and should not
- * be explicitly defined as additional exit points. Knowing all exit points is
+ * post-commit IP are already part of the __rseq_cs section and should not be
+ * explicitly defined as additional exit points. Knowing all exit points is
* useful to assist debuggers stepping over the critical section.
*/
#define RSEQ_ASM_DEFINE_EXIT_POINT(start_ip, exit_ip) \
@@ -127,7 +131,7 @@ int rseq_cmpeqv_storev(intptr_t *v, intptr_t expect, intptr_t newv, int cpu)
rseq_workaround_gcc_asm_size_guess();
__asm__ __volatile__ goto (
- RSEQ_ASM_DEFINE_TABLE(1f, 2f, 4f) /* start, commit, abort */
+ RSEQ_ASM_DEFINE_TABLE(9, 1f, 2f, 4f) /* start, commit, abort */
RSEQ_ASM_DEFINE_EXIT_POINT(1f, %l[cmpfail])
#ifdef RSEQ_COMPARE_TWICE
RSEQ_ASM_DEFINE_EXIT_POINT(1f, %l[error1])
@@ -192,7 +196,7 @@ int rseq_cmpnev_storeoffp_load(intptr_t *v, intptr_t expectnot,
rseq_workaround_gcc_asm_size_guess();
__asm__ __volatile__ goto (
- RSEQ_ASM_DEFINE_TABLE(1f, 2f, 4f) /* start, commit, abort */
+ RSEQ_ASM_DEFINE_TABLE(9, 1f, 2f, 4f) /* start, commit, abort */
RSEQ_ASM_DEFINE_EXIT_POINT(1f, %l[cmpfail])
#ifdef RSEQ_COMPARE_TWICE
RSEQ_ASM_DEFINE_EXIT_POINT(1f, %l[error1])
@@ -261,7 +265,7 @@ int rseq_addv(intptr_t *v, intptr_t count, int cpu)
rseq_workaround_gcc_asm_size_guess();
__asm__ __volatile__ goto (
- RSEQ_ASM_DEFINE_TABLE(1f, 2f, 4f) /* start, commit, abort */
+ RSEQ_ASM_DEFINE_TABLE(9, 1f, 2f, 4f) /* start, commit, abort */
#ifdef RSEQ_COMPARE_TWICE
RSEQ_ASM_DEFINE_EXIT_POINT(1f, %l[error1])
#endif
@@ -316,7 +320,7 @@ int rseq_cmpeqv_trystorev_storev(intptr_t *v, intptr_t expect,
rseq_workaround_gcc_asm_size_guess();
__asm__ __volatile__ goto (
- RSEQ_ASM_DEFINE_TABLE(1f, 2f, 4f) /* start, commit, abort */
+ RSEQ_ASM_DEFINE_TABLE(9, 1f, 2f, 4f) /* start, commit, abort */
RSEQ_ASM_DEFINE_EXIT_POINT(1f, %l[cmpfail])
#ifdef RSEQ_COMPARE_TWICE
RSEQ_ASM_DEFINE_EXIT_POINT(1f, %l[error1])
@@ -389,7 +393,7 @@ int rseq_cmpeqv_trystorev_storev_release(intptr_t *v, intptr_t expect,
rseq_workaround_gcc_asm_size_guess();
__asm__ __volatile__ goto (
- RSEQ_ASM_DEFINE_TABLE(1f, 2f, 4f) /* start, commit, abort */
+ RSEQ_ASM_DEFINE_TABLE(9, 1f, 2f, 4f) /* start, commit, abort */
RSEQ_ASM_DEFINE_EXIT_POINT(1f, %l[cmpfail])
#ifdef RSEQ_COMPARE_TWICE
RSEQ_ASM_DEFINE_EXIT_POINT(1f, %l[error1])
@@ -463,7 +467,7 @@ int rseq_cmpeqv_cmpeqv_storev(intptr_t *v, intptr_t expect,
rseq_workaround_gcc_asm_size_guess();
__asm__ __volatile__ goto (
- RSEQ_ASM_DEFINE_TABLE(1f, 2f, 4f) /* start, commit, abort */
+ RSEQ_ASM_DEFINE_TABLE(9, 1f, 2f, 4f) /* start, commit, abort */
RSEQ_ASM_DEFINE_EXIT_POINT(1f, %l[cmpfail])
#ifdef RSEQ_COMPARE_TWICE
RSEQ_ASM_DEFINE_EXIT_POINT(1f, %l[error1])
@@ -543,7 +547,7 @@ int rseq_cmpeqv_trymemcpy_storev(intptr_t *v, intptr_t expect,
rseq_workaround_gcc_asm_size_guess();
__asm__ __volatile__ goto (
- RSEQ_ASM_DEFINE_TABLE(1f, 2f, 4f) /* start, commit, abort */
+ RSEQ_ASM_DEFINE_TABLE(9, 1f, 2f, 4f) /* start, commit, abort */
RSEQ_ASM_DEFINE_EXIT_POINT(1f, %l[cmpfail])
#ifdef RSEQ_COMPARE_TWICE
RSEQ_ASM_DEFINE_EXIT_POINT(1f, %l[error1])
@@ -664,7 +668,7 @@ int rseq_cmpeqv_trymemcpy_storev_release(intptr_t *v, intptr_t expect,
rseq_workaround_gcc_asm_size_guess();
__asm__ __volatile__ goto (
- RSEQ_ASM_DEFINE_TABLE(1f, 2f, 4f) /* start, commit, abort */
+ RSEQ_ASM_DEFINE_TABLE(9, 1f, 2f, 4f) /* start, commit, abort */
RSEQ_ASM_DEFINE_EXIT_POINT(1f, %l[cmpfail])
#ifdef RSEQ_COMPARE_TWICE
RSEQ_ASM_DEFINE_EXIT_POINT(1f, %l[error1])
diff --git a/tools/testing/selftests/rseq/rseq-ppc.h b/tools/testing/selftests/rseq/rseq-ppc.h
index 24f95649d71e..9df18487fa9f 100644
--- a/tools/testing/selftests/rseq/rseq-ppc.h
+++ b/tools/testing/selftests/rseq/rseq-ppc.h
@@ -33,8 +33,8 @@ do { \
#else /* !RSEQ_SKIP_FASTPATH */
/*
- * The __rseq_table section can be used by debuggers to better handle
- * single-stepping through the restartable critical sections.
+ * The __rseq_cs_ptr_array and __rseq_cs sections can be used by debuggers to
+ * better handle single-stepping through the restartable critical sections.
*/
#ifdef __PPC64__
@@ -46,11 +46,14 @@ do { \
#define __RSEQ_ASM_DEFINE_TABLE(label, version, flags, \
start_ip, post_commit_offset, abort_ip) \
- ".pushsection __rseq_table, \"aw\"\n\t" \
+ ".pushsection __rseq_cs, \"aw\"\n\t" \
".balign 32\n\t" \
__rseq_str(label) ":\n\t" \
".long " __rseq_str(version) ", " __rseq_str(flags) "\n\t" \
".quad " __rseq_str(start_ip) ", " __rseq_str(post_commit_offset) ", " __rseq_str(abort_ip) "\n\t" \
+ ".popsection\n\t" \
+ ".pushsection __rseq_cs_ptr_array, \"aw\"\n\t" \
+ ".quad " __rseq_str(label) "b\n\t" \
".popsection\n\t"
#define RSEQ_ASM_STORE_RSEQ_CS(label, cs_label, rseq_cs) \
@@ -67,8 +70,8 @@ do { \
* Exit points of a rseq critical section consist of all instructions outside
* of the critical section where a critical section can either branch to or
* reach through the normal course of its execution. The abort IP and the
- * post-commit IP are already part of the __rseq_table section and should not
- * be explicitly defined as additional exit points. Knowing all exit points is
+ * post-commit IP are already part of the __rseq_cs section and should not be
+ * explicitly defined as additional exit points. Knowing all exit points is
* useful to assist debuggers stepping over the critical section.
*/
#define RSEQ_ASM_DEFINE_EXIT_POINT(start_ip, exit_ip) \
@@ -85,20 +88,23 @@ do { \
#define __RSEQ_ASM_DEFINE_TABLE(label, version, flags, \
start_ip, post_commit_offset, abort_ip) \
- ".pushsection __rseq_table, \"aw\"\n\t" \
+ ".pushsection __rseq_cs, \"aw\"\n\t" \
".balign 32\n\t" \
__rseq_str(label) ":\n\t" \
".long " __rseq_str(version) ", " __rseq_str(flags) "\n\t" \
/* 32-bit only supported on BE */ \
".long 0x0, " __rseq_str(start_ip) ", 0x0, " __rseq_str(post_commit_offset) ", 0x0, " __rseq_str(abort_ip) "\n\t" \
+ ".popsection\n\t" \
+ ".pushsection __rseq_cs_ptr_array, \"aw\"\n\t" \
+ ".long 0x0, " __rseq_str(label) "b\n\t" \
".popsection\n\t"
/*
* Exit points of a rseq critical section consist of all instructions outside
* of the critical section where a critical section can either branch to or
* reach through the normal course of its execution. The abort IP and the
- * post-commit IP are already part of the __rseq_table section and should not
- * be explicitly defined as additional exit points. Knowing all exit points is
+ * post-commit IP are already part of the __rseq_cs section and should not be
+ * explicitly defined as additional exit points. Knowing all exit points is
* useful to assist debuggers stepping over the critical section.
*/
#define RSEQ_ASM_DEFINE_EXIT_POINT(start_ip, exit_ip) \
diff --git a/tools/testing/selftests/rseq/rseq-s390.h b/tools/testing/selftests/rseq/rseq-s390.h
index b8b5b6f900af..fbb97815d71c 100644
--- a/tools/testing/selftests/rseq/rseq-s390.h
+++ b/tools/testing/selftests/rseq/rseq-s390.h
@@ -37,19 +37,22 @@ do { \
#define __RSEQ_ASM_DEFINE_TABLE(label, version, flags, \
start_ip, post_commit_offset, abort_ip) \
- ".pushsection __rseq_table, \"aw\"\n\t" \
+ ".pushsection __rseq_cs, \"aw\"\n\t" \
".balign 32\n\t" \
__rseq_str(label) ":\n\t" \
".long " __rseq_str(version) ", " __rseq_str(flags) "\n\t" \
".quad " __rseq_str(start_ip) ", " __rseq_str(post_commit_offset) ", " __rseq_str(abort_ip) "\n\t" \
+ ".popsection\n\t" \
+ ".pushsection __rseq_cs_ptr_array, \"aw\"\n\t" \
+ ".quad " __rseq_str(label) "b\n\t" \
".popsection\n\t"
/*
* Exit points of a rseq critical section consist of all instructions outside
* of the critical section where a critical section can either branch to or
* reach through the normal course of its execution. The abort IP and the
- * post-commit IP are already part of the __rseq_table section and should not
- * be explicitly defined as additional exit points. Knowing all exit points is
+ * post-commit IP are already part of the __rseq_cs section and should not be
+ * explicitly defined as additional exit points. Knowing all exit points is
* useful to assist debuggers stepping over the critical section.
*/
#define RSEQ_ASM_DEFINE_EXIT_POINT(start_ip, exit_ip) \
@@ -61,19 +64,22 @@ do { \
#define __RSEQ_ASM_DEFINE_TABLE(label, version, flags, \
start_ip, post_commit_offset, abort_ip) \
- ".pushsection __rseq_table, \"aw\"\n\t" \
+ ".pushsection __rseq_cs, \"aw\"\n\t" \
".balign 32\n\t" \
__rseq_str(label) ":\n\t" \
".long " __rseq_str(version) ", " __rseq_str(flags) "\n\t" \
".long 0x0, " __rseq_str(start_ip) ", 0x0, " __rseq_str(post_commit_offset) ", 0x0, " __rseq_str(abort_ip) "\n\t" \
+ ".popsection\n\t" \
+ ".pushsection __rseq_cs_ptr_array, \"aw\"\n\t" \
+ ".long 0x0, " __rseq_str(label) "b\n\t" \
".popsection\n\t"
/*
* Exit points of a rseq critical section consist of all instructions outside
* of the critical section where a critical section can either branch to or
* reach through the normal course of its execution. The abort IP and the
- * post-commit IP are already part of the __rseq_table section and should not
- * be explicitly defined as additional exit points. Knowing all exit points is
+ * post-commit IP are already part of the __rseq_cs section and should not be
+ * explicitly defined as additional exit points. Knowing all exit points is
* useful to assist debuggers stepping over the critical section.
*/
#define RSEQ_ASM_DEFINE_EXIT_POINT(start_ip, exit_ip) \
diff --git a/tools/testing/selftests/rseq/rseq-x86.h b/tools/testing/selftests/rseq/rseq-x86.h
index 5857570d1c51..2d4887b5d3f0 100644
--- a/tools/testing/selftests/rseq/rseq-x86.h
+++ b/tools/testing/selftests/rseq/rseq-x86.h
@@ -37,13 +37,17 @@ do { \
#define __RSEQ_ASM_DEFINE_TABLE(label, version, flags, \
start_ip, post_commit_offset, abort_ip) \
- ".pushsection __rseq_table, \"aw\"\n\t" \
+ ".pushsection __rseq_cs, \"aw\"\n\t" \
".balign 32\n\t" \
__rseq_str(label) ":\n\t" \
".long " __rseq_str(version) ", " __rseq_str(flags) "\n\t" \
".quad " __rseq_str(start_ip) ", " __rseq_str(post_commit_offset) ", " __rseq_str(abort_ip) "\n\t" \
+ ".popsection\n\t" \
+ ".pushsection __rseq_cs_ptr_array, \"aw\"\n\t" \
+ ".quad " __rseq_str(label) "b\n\t" \
".popsection\n\t"
+
#define RSEQ_ASM_DEFINE_TABLE(label, start_ip, post_commit_ip, abort_ip) \
__RSEQ_ASM_DEFINE_TABLE(label, 0x0, 0x0, start_ip, \
(post_commit_ip - start_ip), abort_ip)
@@ -52,8 +56,8 @@ do { \
* Exit points of a rseq critical section consist of all instructions outside
* of the critical section where a critical section can either branch to or
* reach through the normal course of its execution. The abort IP and the
- * post-commit IP are already part of the __rseq_table section and should not
- * be explicitly defined as additional exit points. Knowing all exit points is
+ * post-commit IP are already part of the __rseq_cs section and should not be
+ * explicitly defined as additional exit points. Knowing all exit points is
* useful to assist debuggers stepping over the critical section.
*/
#define RSEQ_ASM_DEFINE_EXIT_POINT(start_ip, exit_ip) \
@@ -562,11 +566,14 @@ do { \
*/
#define __RSEQ_ASM_DEFINE_TABLE(label, version, flags, \
start_ip, post_commit_offset, abort_ip) \
- ".pushsection __rseq_table, \"aw\"\n\t" \
+ ".pushsection __rseq_cs, \"aw\"\n\t" \
".balign 32\n\t" \
__rseq_str(label) ":\n\t" \
".long " __rseq_str(version) ", " __rseq_str(flags) "\n\t" \
".long " __rseq_str(start_ip) ", 0x0, " __rseq_str(post_commit_offset) ", 0x0, " __rseq_str(abort_ip) ", 0x0\n\t" \
+ ".popsection\n\t" \
+ ".pushsection __rseq_cs_ptr_array, \"aw\"\n\t" \
+ ".long " __rseq_str(label) "b, 0x0\n\t" \
".popsection\n\t"
#define RSEQ_ASM_DEFINE_TABLE(label, start_ip, post_commit_ip, abort_ip) \
@@ -577,8 +584,8 @@ do { \
* Exit points of a rseq critical section consist of all instructions outside
* of the critical section where a critical section can either branch to or
* reach through the normal course of its execution. The abort IP and the
- * post-commit IP are already part of the __rseq_table section and should not
- * be explicitly defined as additional exit points. Knowing all exit points is
+ * post-commit IP are already part of the __rseq_cs section and should not be
+ * explicitly defined as additional exit points. Knowing all exit points is
* useful to assist debuggers stepping over the critical section.
*/
#define RSEQ_ASM_DEFINE_EXIT_POINT(start_ip, exit_ip) \
--
2.11.0
The kernel can be configured to require kexec kernel images and kernel
modules are signed. An IMA policy can be specified on the boot command
line or a custom IMA policy loaded requiring the kexec kernel image and
kernel modules be signed. In addition, systems booted in secure boot
mode with the IMA architecture specific policy enabled, require validly
signed kexec kernel images and kernel modules.
In addition to two methods of signing kernel images and two methods of
signing kernel modules, there are two syscalls for each.
kernel image: PE signature, IMA signature
kexec syscalls: kexec_load, kexec_file_load
Both the PE and IMA kernel image signature can only be verified when
loaded via the kexec_file_load syscall.
kernel moodule: appended signature, IMA signature
kernel module syscalls: init_module, finit_module
The appended kernel module signature can be verified when the kernel
module is loaded via either syscall. The IMA kernel module signature
can only be verified when the kernel module is loaded via the
finit_module syscall.
The selftests in this patch set verify that only signed kernel images
and kernel modules are loaded as required, based on the kernel config,
the secure boot mode, and the IMA runtime policy.
Loading a kernel image or kernel module requires root privileges. To
run just the IMA selftests: sudo make TARGETS=ima kselftest
Changelog:
- Updated tests based on Petr's review, including the defining a common
test to check for root privileges.
- Modified config, removing the CONFIG_KEXEC_VERIFY_SIG requirement.
- Updated the SPDX license to GPL-2.0 based on Shuah's review.
- Updated the secureboot mode test to check the SetupMode as well, based
on David Young's review.
Mimi Zohar (6):
selftests/ima: cleanup the kexec selftest
selftests/ima: define a set of common functions
selftests/ima: define common logging functions
kselftest/ima: define "require_root_privileges"
selftests/ima: kexec_file_load syscall test
selftests/ima: loading kernel modules
Petr Vorel (1):
selftests/ima: Add missing '=y' to config options
tools/testing/selftests/ima/Makefile | 3 +-
tools/testing/selftests/ima/config | 7 +-
tools/testing/selftests/ima/ima_common_lib.sh | 173 +++++++++++++++++++
tools/testing/selftests/ima/test_kernel_module.sh | 93 ++++++++++
.../testing/selftests/ima/test_kexec_file_load.sh | 190 +++++++++++++++++++++
tools/testing/selftests/ima/test_kexec_load.sh | 53 ++----
6 files changed, 476 insertions(+), 43 deletions(-)
create mode 100755 tools/testing/selftests/ima/ima_common_lib.sh
create mode 100755 tools/testing/selftests/ima/test_kernel_module.sh
create mode 100755 tools/testing/selftests/ima/test_kexec_file_load.sh
--
2.7.5
The kmod.sh script breaks because an array is passed as input
instead of a single element input.This patch takes elements
one at a time and passed as input to the condition statement
which in turn fixes the error.There was an issue which had
the need for passing a single digit to the condition statement
which is fixed using regular expression.
Distribution: Debian GNU/Linux buster/sid
Bash Version: 5.0.0(1)-release
Signed-off-by: Jeffrin Jose T <jeffrin(a)rajagiritech.edu.in>
---
tools/testing/selftests/kmod/kmod.sh | 9 ++++++---
1 file changed, 6 insertions(+), 3 deletions(-)
diff --git a/tools/testing/selftests/kmod/kmod.sh b/tools/testing/selftests/kmod/kmod.sh
index 0a76314b4414..49b273c3646e 100755
--- a/tools/testing/selftests/kmod/kmod.sh
+++ b/tools/testing/selftests/kmod/kmod.sh
@@ -526,9 +526,12 @@ function run_all_tests()
TEST_ID=${i%:*:*}
ENABLED=$(get_test_enabled $TEST_ID)
TEST_COUNT=$(get_test_count $TEST_ID)
- if [[ $ENABLED -eq "1" ]]; then
- test_case $TEST_ID $TEST_COUNT
- fi
+ for j in $ENABLED ; do
+ CHECK=${j#*:*:}
+ if [[ $CHECK -eq "1" ]]; then
+ test_case $TEST_ID $TEST_COUNT
+ fi
+ done
done
}
--
2.20.1
From: Thadeu Lima de Souza Cascardo <cascardo(a)canonical.com>
[ Upstream commit af548a27b158d548d41e56255e6eaca1658cc3be ]
Just like commit e2ba732a1681 ("selftests: fib_tests: sleep after
changing carrier"), wait one second to allow linkwatch to propagate the
carrier change to the stack.
There are two sets of carrier tests. The first slept after the carrier
was set to off, and when the second set ran, it was likely that the
linkwatch would be able to run again without much delay, reducing the
likelihood of a race. However, if you run 'fib_tests.sh -t carrier' on a
loop, you will quickly notice the failures.
Sleeping on the second set of tests make the failures go away.
Cc: David Ahern <dsahern(a)gmail.com>
Signed-off-by: Thadeu Lima de Souza Cascardo <cascardo(a)canonical.com>
Reviewed-by: David Ahern <dsahern(a)gmail.com>
Signed-off-by: David S. Miller <davem(a)davemloft.net>
Signed-off-by: Sasha Levin <sashal(a)kernel.org>
---
tools/testing/selftests/net/fib_tests.sh | 1 +
1 file changed, 1 insertion(+)
diff --git a/tools/testing/selftests/net/fib_tests.sh b/tools/testing/selftests/net/fib_tests.sh
index 0f45633bd634..a4ccde0e473b 100755
--- a/tools/testing/selftests/net/fib_tests.sh
+++ b/tools/testing/selftests/net/fib_tests.sh
@@ -385,6 +385,7 @@ fib_carrier_unicast_test()
set -e
$IP link set dev dummy0 carrier off
+ sleep 1
set +e
echo " Carrier down"
--
2.19.1
From: Thadeu Lima de Souza Cascardo <cascardo(a)canonical.com>
[ Upstream commit af548a27b158d548d41e56255e6eaca1658cc3be ]
Just like commit e2ba732a1681 ("selftests: fib_tests: sleep after
changing carrier"), wait one second to allow linkwatch to propagate the
carrier change to the stack.
There are two sets of carrier tests. The first slept after the carrier
was set to off, and when the second set ran, it was likely that the
linkwatch would be able to run again without much delay, reducing the
likelihood of a race. However, if you run 'fib_tests.sh -t carrier' on a
loop, you will quickly notice the failures.
Sleeping on the second set of tests make the failures go away.
Cc: David Ahern <dsahern(a)gmail.com>
Signed-off-by: Thadeu Lima de Souza Cascardo <cascardo(a)canonical.com>
Reviewed-by: David Ahern <dsahern(a)gmail.com>
Signed-off-by: David S. Miller <davem(a)davemloft.net>
Signed-off-by: Sasha Levin <sashal(a)kernel.org>
---
tools/testing/selftests/net/fib_tests.sh | 1 +
1 file changed, 1 insertion(+)
diff --git a/tools/testing/selftests/net/fib_tests.sh b/tools/testing/selftests/net/fib_tests.sh
index 802b4af18729..1080ff55a788 100755
--- a/tools/testing/selftests/net/fib_tests.sh
+++ b/tools/testing/selftests/net/fib_tests.sh
@@ -388,6 +388,7 @@ fib_carrier_unicast_test()
set -e
$IP link set dev dummy0 carrier off
+ sleep 1
set +e
echo " Carrier down"
--
2.19.1
Note: this version will likely trivially conflict with some cleanup
patches I sent to Bjorn. So this is meant for review purposes only.
If there are no objections, I'd like to look at getting it merged in
the next cycle through the NTB tree.
--
Changes in v2:
* Cleaned up the changes in intel_irq_remapping.c to make them
less confusing and add a comment. (Per discussion with Jacob and
Joerg)
* Fixed a nit from Bjorn and collected his Ack
* Added a Kconfig dependancy on CONFIG_PCI_MSI for CONFIG_NTB_MSI
as the Kbuild robot hit a random config that didn't build
without it.
* Worked in a callback for when the MSI descriptor changes so that
the clients can resend the new address and data values to the peer.
On my test system this was never necessary, but there may be
other platforms where this can occur. I tested this by hacking
in a path to rewrite the MSI descriptor when I change the cpu
affinity of an IRQ. There's a bit of uncertainty over the latency
of the change, but without hardware this can acctually occur on
we can't test this. This was the result of a discussion with Dave.
--
This patch series adds optional support for using MSI interrupts instead
of NTB doorbells in ntb_transport. This is desirable seeing doorbells on
current hardware are quite slow and therefore switching to MSI interrupts
provides a significant performance gain. On switchtec hardware, a simple
apples-to-apples comparison shows ntb_netdev/iperf numbers going from
3.88Gb/s to 14.1Gb/s when switching to MSI interrupts.
To do this, a couple changes are required outside of the NTB tree:
1) The IOMMU must know to accept MSI requests from aliased bused numbers
seeing NTB hardware typically sends proxied request IDs through
additional requester IDs. The first patch in this series adds support
for the Intel IOMMU. A quirk to add these aliases for switchtec hardware
was already accepted. See commit ad281ecf1c7d ("PCI: Add DMA alias quirk
for Microsemi Switchtec NTB") for a description of NTB proxy IDs and why
this is necessary.
2) NTB transport (and other clients) may often need more MSI interrupts
than the NTB hardware actually advertises support for. However, seeing
these interrupts will not be triggered by the hardware but through an
NTB memory window, the hardware does not actually need support or need
to know about them. Therefore we add the concept of Virtual MSI
interrupts which are allocated just like any other MSI interrupt but
are not programmed into the hardware's MSI table. This is done in
Patch 2 and then made use of in Patch 3.
The remaining patches in this series add a library for dealing with MSI
interrupts, a test client and finally support in ntb_transport.
The series is based off of v5.0-rc4 and I've tested it on top of a
of the patches I've already sent to the NTB tree (though they are
independent changes). A git repo is available here:
https://github.com/sbates130272/linux-p2pmem/ ntb_transport_msi_v2
Thanks,
Logan
--
Logan Gunthorpe (12):
iommu/vt-d: Implement dma_[un]map_resource()
NTB: ntb_transport: Ensure the destination buffer is mapped for TX DMA
iommu/vt-d: Add helper to set an IRTE to verify only the bus number
iommu/vt-d: Allow interrupts from the entire bus for aliased devices
PCI/MSI: Support allocating virtual MSI interrupts
PCI/switchtec: Add module parameter to request more interrupts
NTB: Introduce functions to calculate multi-port resource index
NTB: Rename ntb.c to support multiple source files in the module
NTB: Introduce MSI library
NTB: Introduce NTB MSI Test Client
NTB: Add ntb_msi_test support to ntb_test
NTB: Add MSI interrupt support to ntb_transport
drivers/iommu/intel-iommu.c | 23 +-
drivers/iommu/intel_irq_remapping.c | 32 +-
drivers/ntb/Kconfig | 11 +
drivers/ntb/Makefile | 3 +
drivers/ntb/{ntb.c => core.c} | 0
drivers/ntb/msi.c | 415 +++++++++++++++++++++++
drivers/ntb/ntb_transport.c | 197 ++++++++++-
drivers/ntb/test/Kconfig | 9 +
drivers/ntb/test/Makefile | 1 +
drivers/ntb/test/ntb_msi_test.c | 433 ++++++++++++++++++++++++
drivers/pci/msi.c | 55 ++-
drivers/pci/switch/switchtec.c | 12 +-
include/linux/msi.h | 8 +
include/linux/ntb.h | 143 ++++++++
include/linux/pci.h | 9 +
tools/testing/selftests/ntb/ntb_test.sh | 54 ++-
16 files changed, 1379 insertions(+), 26 deletions(-)
rename drivers/ntb/{ntb.c => core.c} (100%)
create mode 100644 drivers/ntb/msi.c
create mode 100644 drivers/ntb/test/ntb_msi_test.c
--
2.19.0
When the CONFIG_HOTPLUG_CPU is not set, there won't be a "hotplug"
directory in /sys/devices/system/cpu/. Make use of this fact to check
if we need to skip this test.
Signed-off-by: Po-Hsu Lin <po-hsu.lin(a)canonical.com>
---
tools/testing/selftests/cpu-hotplug/cpu-on-off-test.sh | 5 +++++
1 file changed, 5 insertions(+)
diff --git a/tools/testing/selftests/cpu-hotplug/cpu-on-off-test.sh b/tools/testing/selftests/cpu-hotplug/cpu-on-off-test.sh
index 0d26b5e..27275a1 100755
--- a/tools/testing/selftests/cpu-hotplug/cpu-on-off-test.sh
+++ b/tools/testing/selftests/cpu-hotplug/cpu-on-off-test.sh
@@ -23,6 +23,11 @@ prerequisite()
exit $ksft_skip
fi
+ if [ ! -d $SYSFS/devices/system/cpu/hotplug/ ]; then
+ echo $msg CONFIG_HOTPLUG_CPU needs to be enabled >&2
+ exit $ksft_skip
+ fi
+
if ! ls $SYSFS/devices/system/cpu/cpu* > /dev/null 2>&1; then
echo $msg cpu hotplug is not supported >&2
exit $ksft_skip
--
2.7.4
The kernel can be configured to require kexec kernel images and kernel
modules are signed. An IMA policy can be specified on the boot command
line or a custom IMA policy loaded requiring the kexec kernel image and
kernel modules be signed. In addition, systems booted in secure boot
mode with the IMA architecture specific policy enabled, require validly
signed kexec kernel images and kernel modules.
There are two methods of signing kernel images and two methods of
signing kernel modules. In addition, there are two syscalls for each.
kernel image: PE signature, IMA signature
kexec syscalls: kexec_load, kexec_file_load
Both the PE and IMA kernel image signature can only be verified when
loaded via the kexec_file_load syscall.
kernel moodule: appended signature, IMA signature
kernel module syscalls: init_module, finit_module
The appended kernel module signature can be verified when the kernel
module is loaded via either syscall. The IMA kernel module signature
can only be verified when the kernel module is loaded via the
finit_module syscall.
The selftests in this patch set verify that only signed kernel images
and kernel modules are loaded as required, based on the kernel config,
the secure boot mode, and the IMA runtime policy.
Loading a kernel image or kernel module requires root privileges. To
run just the IMA selftests: sudo make TARGETS=ima kselftest
Mimi Zohar (5):
selftests/ima: cleanup the kexec selftest
selftests/ima: define a set of common functions
selftests/ima: define common logging functions
selftests/ima: kexec_file_load syscall test
selftests/ima: loading kernel modules
tools/testing/selftests/ima/Makefile | 3 +-
tools/testing/selftests/ima/common_lib.sh | 154 ++++++++++++++++
tools/testing/selftests/ima/test_kernel_module.sh | 96 ++++++++++
.../testing/selftests/ima/test_kexec_file_load.sh | 195 +++++++++++++++++++++
tools/testing/selftests/ima/test_kexec_load.sh | 53 ++----
5 files changed, 463 insertions(+), 38 deletions(-)
create mode 100755 tools/testing/selftests/ima/common_lib.sh
create mode 100755 tools/testing/selftests/ima/test_kernel_module.sh
create mode 100755 tools/testing/selftests/ima/test_kexec_file_load.sh
--
2.7.5
Hi Linus,
Please pull the following Kselftest update for Linux 5.1-rc1
This Kselftest update for Linux 5.1-rc1 consists of
- ir test compile warnings fixes
- seccomp test fixes and improvements from Tycho Andersen and Kees Cook
- ftrace fixes to non-POSIX-compliant constructs in colored output code
and handling absence of tput from Juerg Haefliger
diff is attached.
thanks,
-- Shuah
----------------------------------------------------------------
The following changes since commit d13937116f1e82bf508a6325111b322c30c85eb9:
Linux 5.0-rc6 (2019-02-10 14:42:20 -0800)
are available in the Git repository at:
git://git.kernel.org/pub/scm/linux/kernel/git/shuah/linux-kselftest
tags/linux-kselftest-5.1-rc1
for you to fetch changes up to 0e27ded1159f62ab1a4e723796246bd5b1793b93:
selftests/ftrace: Handle the absence of tput (2019-02-25 07:48:01 -0700)
----------------------------------------------------------------
linux-kselftest-5.1-rc1
This Kselftest update for Linux 5.1-rc1 consists of
- ir test compile warnings fixes
- seccomp test fixes and improvements from Tycho Andersen and Kees Cook
- ftrace fixes to non-POSIX-compliant constructs in colored output code
and handling absence of tput from Juerg Haefliger
----------------------------------------------------------------
Juerg Haefliger (3):
selftests/ftrace: Replace echo -e with printf
selftests/ftrace: Replace \e with \033
selftests/ftrace: Handle the absence of tput
Kees Cook (2):
selftests/harness: Update named initializer syntax
selftests/seccomp: Actually sleep for 1/10th second
Shuah Khan (3):
selftests: ir: fix warning: "%s" directive output may be
truncated ’ directive output may be truncated
selftests: ir: skip when lirc device doesn't exist.
selftests: ir: skip when non-root user runs the test
Tycho Andersen (6):
selftests: don't kill child immediately in get_metadata() test
selftests: fix typo in seccomp_bpf.c
selftest: include stdio.h in kselftest.h
selftests: skip seccomp get_metadata test if not real root
selftests: set NO_NEW_PRIVS bit in seccomp user tests
selftests: unshare userns in seccomp pidns testcases
tools/testing/selftests/ftrace/ftracetest | 21 +++++++-----
tools/testing/selftests/ir/ir_loopback.c | 6 ++--
tools/testing/selftests/ir/ir_loopback.sh | 5 +++
tools/testing/selftests/kselftest.h | 1 +
tools/testing/selftests/kselftest_harness.h | 10 +++---
tools/testing/selftests/seccomp/seccomp_bpf.c | 47
+++++++++++++++++++++++----
6 files changed, 68 insertions(+), 22 deletions(-)
----------------------------------------------------------------
Atom-based CPUs trigger stack fault when invoke 32-bit SYSENTER instruction
with invalid register values. So we also need sigbus handling in this case.
Following is assembly when the fault expception happens.
(gdb) disassemble $eip
Dump of assembler code for function __kernel_vsyscall:
0xf7fd8fe0 <+0>: push %ecx
0xf7fd8fe1 <+1>: push %edx
0xf7fd8fe2 <+2>: push %ebp
0xf7fd8fe3 <+3>: mov %esp,%ebp
0xf7fd8fe5 <+5>: sysenter
0xf7fd8fe7 <+7>: int $0x80
=> 0xf7fd8fe9 <+9>: pop %ebp
0xf7fd8fea <+10>: pop %edx
0xf7fd8feb <+11>: pop %ecx
0xf7fd8fec <+12>: ret
End of assembler dump.
Accroding to Intel SDM, this could also be a Stack Segment Fault(#SS, 12),
except a normal Page Fault(#PF, 14). Especially, in section 6.9 of Vol.3A,
both stack and page faults are within the 10th(lowest priority) class, and
as it said, "exceptions within each class are implementation-dependent and
may vary from processor to processor". It's expected for processors like
Intel Atom to trigger stack fault(sigbus), while we get page fault(sigsegv)
from common Core processors.
Signed-off-by: Tong Bo <bo.tong(a)intel.com>
---
tools/testing/selftests/x86/syscall_arg_fault.c | 6 ++++--
1 file changed, 4 insertions(+), 2 deletions(-)
diff --git a/tools/testing/selftests/x86/syscall_arg_fault.c b/tools/testing/selftests/x86/syscall_arg_fault.c
index 7db4fc9..38cd246 100644
--- a/tools/testing/selftests/x86/syscall_arg_fault.c
+++ b/tools/testing/selftests/x86/syscall_arg_fault.c
@@ -43,7 +43,7 @@ static sigjmp_buf jmpbuf;
static volatile sig_atomic_t n_errs;
-static void sigsegv(int sig, siginfo_t *info, void *ctx_void)
+static void sigsegv_or_sigbus(int sig, siginfo_t *info, void *ctx_void)
{
ucontext_t *ctx = (ucontext_t*)ctx_void;
@@ -73,7 +73,9 @@ int main()
if (sigaltstack(&stack, NULL) != 0)
err(1, "sigaltstack");
- sethandler(SIGSEGV, sigsegv, SA_ONSTACK);
+ sethandler(SIGSEGV, sigsegv_or_sigbus, SA_ONSTACK);
+ /* Atom CPUs may trigger sigbus for below SYSENTER exception case */
+ sethandler(SIGBUS, sigsegv_or_sigbus, SA_ONSTACK);
sethandler(SIGILL, sigill, SA_ONSTACK);
/*
--
2.7.4
This patchset is meant to be merged together with "arm64 relaxed ABI" [1].
arm64 has a feature called Top Byte Ignore, which allows to embed pointer
tags into the top byte of each pointer. Userspace programs (such as
HWASan, a memory debugging tool [2]) might use this feature and pass
tagged user pointers to the kernel through syscalls or other interfaces.
Right now the kernel is already able to handle user faults with tagged
pointers, due to these patches:
1. 81cddd65 ("arm64: traps: fix userspace cache maintenance emulation on a
tagged pointer")
2. 7dcd9dd8 ("arm64: hw_breakpoint: fix watchpoint matching for tagged
pointers")
3. 276e9327 ("arm64: entry: improve data abort handling of tagged
pointers")
This patchset extends tagged pointer support to syscall arguments.
For non-memory syscalls this is done by untaging user pointers when the
kernel performs pointer checking to find out whether the pointer comes
from userspace (most notably in access_ok). The untagging is done only
when the pointer is being checked, the tag is preserved as the pointer
makes its way through the kernel.
Since memory syscalls (mmap, mprotect, etc.) don't do memory accesses but
rather deal with memory ranges, untagged pointers are better suited to
describe memory ranges internally. Thus for memory syscalls we untag
pointers completely when they enter the kernel.
One of the alternative approaches to untagging that was considered is to
completely strip the pointer tag as the pointer enters the kernel with
some kind of a syscall wrapper, but that won't work with the countless
number of different ioctl calls. With this approach we would need a custom
wrapper for each ioctl variation, which doesn't seem practical.
The following testing approaches has been taken to find potential issues
with user pointer untagging:
1. Static testing (with sparse [3] and separately with a custom static
analyzer based on Clang) to track casts of __user pointers to integer
types to find places where untagging needs to be done.
2. Static testing with grep to find parts of the kernel that call
find_vma() (and other similar functions) or directly compare against
vm_start/vm_end fields of vma.
3. Static testing with grep to find parts of the kernel that compare
user pointers with TASK_SIZE or other similar consts and macros.
4. Dynamic testing: adding BUG_ON(has_tag(addr)) to find_vma() and running
a modified syzkaller version that passes tagged pointers to the kernel.
Based on the results of the testing the requried patches have been added
to the patchset.
This patchset has been merged into the Pixel 2 kernel tree and is now
being used to enable testing of Pixel 2 phones with HWASan.
This patchset is a prerequisite for ARM's memory tagging hardware feature
support [4].
Thanks!
[1] https://lkml.org/lkml/2018/12/10/402
[2] http://clang.llvm.org/docs/HardwareAssistedAddressSanitizerDesign.html
[3] https://github.com/lucvoo/sparse-dev/commit/5f960cb10f56ec2017c128ef9d16060…
[4] https://community.arm.com/processors/b/blog/posts/arm-a-profile-architectur…
Changes in v10:
- Added "mm, arm64: untag user pointers passed to memory syscalls" back.
- New patch "fs, arm64: untag user pointers in fs/userfaultfd.c".
- New patch "net, arm64: untag user pointers in tcp_zerocopy_receive".
- New patch "kernel, arm64: untag user pointers in prctl_set_mm*".
- New patch "tracing, arm64: untag user pointers in seq_print_user_ip".
Changes in v9:
- Rebased onto 4.20-rc6.
- Used u64 instead of __u64 in type casts in the untagged_addr macro for
arm64.
- Added braces around (addr) in the untagged_addr macro for other arches.
Changes in v8:
- Rebased onto 65102238 (4.20-rc1).
- Added a note to the cover letter on why syscall wrappers/shims that untag
user pointers won't work.
- Added a note to the cover letter that this patchset has been merged into
the Pixel 2 kernel tree.
- Documentation fixes, in particular added a list of syscalls that don't
support tagged user pointers.
Changes in v7:
- Rebased onto 17b57b18 (4.19-rc6).
- Dropped the "arm64: untag user address in __do_user_fault" patch, since
the existing patches already handle user faults properly.
- Dropped the "usb, arm64: untag user addresses in devio" patch, since the
passed pointer must come from a vma and therefore be untagged.
- Dropped the "arm64: annotate user pointers casts detected by sparse"
patch (see the discussion to the replies of the v6 of this patchset).
- Added more context to the cover letter.
- Updated Documentation/arm64/tagged-pointers.txt.
Changes in v6:
- Added annotations for user pointer casts found by sparse.
- Rebased onto 050cdc6c (4.19-rc1+).
Changes in v5:
- Added 3 new patches that add untagging to places found with static
analysis.
- Rebased onto 44c929e1 (4.18-rc8).
Changes in v4:
- Added a selftest for checking that passing tagged pointers to the
kernel succeeds.
- Rebased onto 81e97f013 (4.18-rc1+).
Changes in v3:
- Rebased onto e5c51f30 (4.17-rc6+).
- Added linux-arch@ to the list of recipients.
Changes in v2:
- Rebased onto 2d618bdf (4.17-rc3+).
- Removed excessive untagging in gup.c.
- Removed untagging pointers returned from __uaccess_mask_ptr.
Changes in v1:
- Rebased onto 4.17-rc1.
Changes in RFC v2:
- Added "#ifndef untagged_addr..." fallback in linux/uaccess.h instead of
defining it for each arch individually.
- Updated Documentation/arm64/tagged-pointers.txt.
- Dropped "mm, arm64: untag user addresses in memory syscalls".
- Rebased onto 3eb2ce82 (4.16-rc7).
Reviewed-by: Luc Van Oostenryck <luc.vanoostenryck(a)gmail.com>
Signed-off-by: Andrey Konovalov <andreyknvl(a)google.com>
Andrey Konovalov (12):
uaccess: add untagged_addr definition for other arches
arm64: untag user pointers in access_ok and __uaccess_mask_ptr
lib, arm64: untag user pointers in strn*_user
mm, arm64: untag user pointers passed to memory syscalls
mm, arm64: untag user pointers in mm/gup.c
fs, arm64: untag user pointers in copy_mount_options
fs, arm64: untag user pointers in fs/userfaultfd.c
net, arm64: untag user pointers in tcp_zerocopy_receive
kernel, arm64: untag user pointers in prctl_set_mm*
tracing, arm64: untag user pointers in seq_print_user_ip
arm64: update Documentation/arm64/tagged-pointers.txt
selftests, arm64: add a selftest for passing tagged pointers to kernel
Documentation/arm64/tagged-pointers.txt | 25 +++++++++++--------
arch/arm64/include/asm/uaccess.h | 10 +++++---
fs/namespace.c | 2 +-
fs/userfaultfd.c | 5 ++++
include/linux/memory.h | 4 +++
ipc/shm.c | 2 ++
kernel/sys.c | 14 +++++++++++
kernel/trace/trace_output.c | 2 +-
lib/strncpy_from_user.c | 2 ++
lib/strnlen_user.c | 2 ++
mm/gup.c | 4 +++
mm/madvise.c | 2 ++
mm/mempolicy.c | 5 ++++
mm/migrate.c | 1 +
mm/mincore.c | 2 ++
mm/mlock.c | 5 ++++
mm/mmap.c | 7 ++++++
mm/mprotect.c | 2 ++
mm/mremap.c | 2 ++
mm/msync.c | 2 ++
net/ipv4/tcp.c | 2 ++
tools/testing/selftests/arm64/.gitignore | 1 +
tools/testing/selftests/arm64/Makefile | 11 ++++++++
.../testing/selftests/arm64/run_tags_test.sh | 12 +++++++++
tools/testing/selftests/arm64/tags_test.c | 19 ++++++++++++++
25 files changed, 129 insertions(+), 16 deletions(-)
create mode 100644 tools/testing/selftests/arm64/.gitignore
create mode 100644 tools/testing/selftests/arm64/Makefile
create mode 100755 tools/testing/selftests/arm64/run_tags_test.sh
create mode 100644 tools/testing/selftests/arm64/tags_test.c
--
2.21.0.rc0.258.g878e2cd30e-goog
eBPF "restricted C" code can be compiled with LLVM/clang using target
triplets like armv7l-unknown-linux-gnueabihf and loaded/run with small
cross-compiled gobpf/elf [1] programs without requiring a full BCC
port which is also undesirable on small embedded systems due to its
size footprint. The only missing pieces are these helper macros which
otherwise have to be redefined by each eBPF arm program.
[1] https://github.com/iovisor/gobpf/tree/master/elf
Signed-off-by: Adrian Ratiu <adrian.ratiu(a)collabora.com>
---
tools/testing/selftests/bpf/bpf_helpers.h | 18 ++++++++++++++++++
1 file changed, 18 insertions(+)
diff --git a/tools/testing/selftests/bpf/bpf_helpers.h b/tools/testing/selftests/bpf/bpf_helpers.h
index 6c77cf7bedce..f7883576f445 100644
--- a/tools/testing/selftests/bpf/bpf_helpers.h
+++ b/tools/testing/selftests/bpf/bpf_helpers.h
@@ -232,6 +232,9 @@ static int (*bpf_skb_pull_data)(void *, int len) =
#elif defined(__TARGET_ARCH_s930x)
#define bpf_target_s930x
#define bpf_target_defined
+#elif defined(__TARGET_ARCH_arm)
+ #define bpf_target_arm
+ #define bpf_target_defined
#elif defined(__TARGET_ARCH_arm64)
#define bpf_target_arm64
#define bpf_target_defined
@@ -254,6 +257,8 @@ static int (*bpf_skb_pull_data)(void *, int len) =
#define bpf_target_x86
#elif defined(__s390x__)
#define bpf_target_s930x
+#elif defined(__arm__)
+ #define bpf_target_arm
#elif defined(__aarch64__)
#define bpf_target_arm64
#elif defined(__mips__)
@@ -291,6 +296,19 @@ static int (*bpf_skb_pull_data)(void *, int len) =
#define PT_REGS_SP(x) ((x)->gprs[15])
#define PT_REGS_IP(x) ((x)->psw.addr)
+#elif defined(bpf_target_arm)
+
+#define PT_REGS_PARM1(x) ((x)->uregs[0])
+#define PT_REGS_PARM2(x) ((x)->uregs[1])
+#define PT_REGS_PARM3(x) ((x)->uregs[2])
+#define PT_REGS_PARM4(x) ((x)->uregs[3])
+#define PT_REGS_PARM5(x) ((x)->uregs[4])
+#define PT_REGS_RET(x) ((x)->uregs[14])
+#define PT_REGS_FP(x) ((x)->uregs[11]) /* Works only with CONFIG_FRAME_POINTER */
+#define PT_REGS_RC(x) ((x)->uregs[0])
+#define PT_REGS_SP(x) ((x)->uregs[13])
+#define PT_REGS_IP(x) ((x)->uregs[12])
+
#elif defined(bpf_target_arm64)
#define PT_REGS_PARM1(x) ((x)->regs[0])
--
2.20.1
On Thu, Feb 28, 2019 at 10:02 AM Stephen Boyd <sboyd(a)kernel.org> wrote:
>
> Quoting Brendan Higgins (2019-02-28 01:03:24)
> > On Tue, Feb 26, 2019 at 12:35 PM Stephen Boyd <sboyd(a)kernel.org> wrote:
> > >
> > > when they need to abort and then the test runner would detect that error
> > > via the return value from the 'run test' function. That would be a more
> > > direct approach, but also more verbose than a single KUNIT_ASSERT()
> > > line. It would be more kernel idiomatic too because the control flow
> >
> > Yeah, I was intentionally going against that idiom. I think that idiom
> > makes test logic more complicated than it needs to be, especially if
> > the assertion failure happens in a helper function; then you have to
> > pass that error all the way back up. It is important that test code
> > should be as simple as possible to the point of being immediately
> > obviously correct at first glance because there are no tests for
> > tests.
> >
> > The idea with assertions is that you use them to state all the
> > preconditions for your test. Logically speaking, these are the
> > premises of the test case, so if a premise isn't true, there is no
> > point in continuing the test case because there are no conclusions
> > that can be drawn without the premises. Whereas, the expectation is
> > the thing you are trying to prove. It is not used universally in
> > x-unit style test frameworks, but I really like it as a convention.
> > You could still express the idea of a premise using the above idiom,
> > but I think KUNIT_ASSERT_* states the intended idea perfectly.
>
> Fair enough. It would be great if these sorts of things were described
> in the commit text.
Good point. Will fix.
>
> Is the assumption that things like held locks and refcounted elements
> won't exist when one of these assertions is made? It sounds like some of
> the cleanup logic could be fairly complicated if a helper function
> changes some state and then an assert fails and we have to unwind all
> the state from a corrupt location. A similar problem exists for a test
> timeout too. How do we get back to a sane state if the test locks up for
> a long time? Just don't try?
It depends on the situation, if it is part of a KUnit test itself
(probably not code under test), then you can use the kunit_resource
API: https://lkml.org/lkml/2019/2/14/1125; it is inspired by the
devm_* family of functions, such that when a KUnit test case ends, for
any reason, all the kunit_resources are automatically cleaned up.
Similarly, kunit_module.exit is called at the end of every test case,
regardless of how it terminates.
>
> >
> > > isn't hidden inside a macro and it isn't intimately connected with
> > > kthreads and completions.
> >
> > Yeah, I wasn't a fan of that myself, but it was broadly available. My
> > previous version (still the architecture specific version for UML, not
> > in this patchset though) relies on UML_LONGJMP, but is obviously only
> > works on UML. A number of people wanted support for other
> > architectures. Rob and Luis specifically wanted me to provide a
> > version of abort that would work on any architecture, even if it only
> > had reduced functionality; I thought this fit the bill okay.
>
> Ok.
>
> >
> > >
> > > >
> > > > diff --git a/kunit/test.c b/kunit/test.c
> > > > index d18c50d5ed671..6e5244642ab07 100644
> > > > --- a/kunit/test.c
> > > > +++ b/kunit/test.c
> > > [...]
> > > > +
> > > > +static void kunit_generic_throw(struct kunit_try_catch *try_catch)
> > > > +{
> > > > + try_catch->context.try_result = -EFAULT;
> > > > + complete_and_exit(try_catch->context.try_completion, -EFAULT);
> > > > +}
> > > > +
> > > > +static int kunit_generic_run_threadfn_adapter(void *data)
> > > > +{
> > > > + struct kunit_try_catch *try_catch = data;
> > > >
> > > > + try_catch->try(&try_catch->context);
> > > > +
> > > > + complete_and_exit(try_catch->context.try_completion, 0);
> > >
> > > The exit code doesn't matter, right? If so, it might be clearer to just
> > > return 0 from this function because kthreads exit themselves as far as I
> > > recall.
> >
> > You mean complete and then return?
>
> Yes. I was confused for a minute because I thought the exit code was
> checked, but it isn't. Instead, the try_catch->context.try_result is
> where the test result goes, so calling exit explicitly doesn't seem to
> be important here, but it is important in the throw case.
Yep.
>
> >
> > >
> > > > + else if (exit_code)
> > > > + kunit_err(test, "Unknown error: %d", exit_code);
> > > > +}
> > > > +
> > > > +void kunit_generic_try_catch_init(struct kunit_try_catch *try_catch)
> > > > +{
> > > > + try_catch->run = kunit_generic_run_try_catch;
> > >
> > > Is the idea that 'run' would be anything besides
> > > 'kunit_generic_run_try_catch'? If it isn't going to be different, then
> >
> > Yeah, it can be overridden with an architecture specific version.
> >
> > > maybe it's simpler to just have a function like
> > > kunit_generic_run_try_catch() that is called by the unit tests instead
> > > of having to write 'try_catch->run(try_catch)' and indirect for the
> > > basic case. Maybe I've missed the point entirely though and this is all
> > > scaffolding for more complicated exception handling later on.
> >
> > Yeah, the idea is that different architectures can override exception
> > handling with their own implementation. This is just the generic one.
> > For example, UML has one that doesn't depend on kthreads or
> > completions; the UML version also allows recovery from some segfault
> > conditions.
>
> Ok, got it. It may still be nice to have a wrapper or macro for that
> try_catch->run(try_catch) statement so we don't have to know that a
> try_catch struct has a run member.
>
> static inline void kunit_run_try_catch(struct kunit_try_catch *try_catch)
> {
> try_catch->run(try_catch);
> }
Makes sense. Will fix in the next revision.
Use /bin/echo for console output with options like non
newline (-n) and/or backslash escape (-e).
Tom Zanussi reported that when he tested ftracetest, it
shows "-e" and "-n" options on the console, since a system
which uses dash as the alias of /bin/sh, uses dash built-in
echo command which doesn't accept "-e".
To avoid this issue, use /bin/echo instead of echo for
the output with options.
Fixes: 8f381ac4d321 ("selftests/ftrace: Add color to the PASS / FAIL results")
Link: http://lkml.kernel.org/r/cover.1542221862.git.tom.zanussi@linux.intel.com
Reported-by: Tom Zanussi <zanussi(a)kernel.org>
Suggested-by: Tom Zanussi <zanussi(a)kernel.org>
Signed-off-by: Masami Hiramatsu <mhiramat(a)kernel.org>
---
tools/testing/selftests/ftrace/ftracetest | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/tools/testing/selftests/ftrace/ftracetest b/tools/testing/selftests/ftrace/ftracetest
index 75244db70331..ba670b452bdb 100755
--- a/tools/testing/selftests/ftrace/ftracetest
+++ b/tools/testing/selftests/ftrace/ftracetest
@@ -173,8 +173,8 @@ strip_esc() {
}
prlog() { # messages
- echo -e "$@"
- [ "$LOG_FILE" ] && echo -e "$@" | strip_esc >> $LOG_FILE
+ /bin/echo -e "$@"
+ [ "$LOG_FILE" ] && /bin/echo -e "$@" | strip_esc >> $LOG_FILE
}
catlog() { #file
cat $1
Introduce in-kernel headers and other artifacts which are made available
as an archive through proc (/proc/kheaders.tar.xz file). This archive makes
it possible to build kernel modules, run eBPF programs, and other
tracing programs that need to extend the kernel for tracing purposes
without any dependency on the file system having headers and build
artifacts.
On Android and embedded systems, it is common to switch kernels but not
have kernel headers available on the file system. Raw kernel headers
also cannot be copied into the filesystem like they can be on other
distros, due to licensing and other issues. There's no linux-headers
package on Android. Further once a different kernel is booted, any
headers stored on the file system will no longer be useful. By storing
the headers as a compressed archive within the kernel, we can avoid these
issues that have been a hindrance for a long time.
The feature is also buildable as a module just in case the user desires
it not being part of the kernel image. This makes it possible to load
and unload the headers on demand. A tracing program, or a kernel module
builder can load the module, do its operations, and then unload the
module to save kernel memory. The total memory needed is 3.8MB.
The code to read the headers is based on /proc/config.gz code and uses
the same technique to embed the headers.
To build a module, the below steps have been tested on an x86 machine:
modprobe kheaders
rm -rf $HOME/headers
mkdir -p $HOME/headers
tar -xvf /proc/kheaders.tar.xz -C $HOME/headers >/dev/null
cd my-kernel-module
make -C $HOME/headers M=$(pwd) modules
rmmod kheaders
Additional notes:
(1)
A limitation of module building with this is, since Module.symvers is
not available in the archive due to a cyclic dependency with building of
the archive into the kernel or module binaries, the modules built using
the archive will not contain symbol versioning (modversion). This is
usually not an issue since the idea of this patch is to build a kernel
module on the fly and load it into the same kernel. An appropriate
warning is already printed by the kernel to alert the user of modules
not having modversions when built using the archive. For building with
modversions, the user can use traditional header packages. For our
tracing usecases, we build modules on the fly with this so it is not a
concern.
(2) I have left IKHD_ST and IKHD_ED markers as is to facilitate
future patches that would extract the headers from a kernel or module
image.
Signed-off-by: Joel Fernandes (Google) <joel(a)joelfernandes.org>
---
Changes since v2:
(Thanks to Masahiro Yamada for several excellent suggestions)
- Added support for out of tree builds.
- Added incremental build support bringing down build time of
incremental builds from 50 seconds to 5 seconds.
- Fixed various small nits / cleanups.
- clean ups to kheaders.c pointed by Alexey Dobriyan.
- Fixed MODULE_LICENSE in test module and kheaders.c
- Dropped Module.symvers from archive due to circular dependency.
Changes since v1:
- removed IKH_EXTRA variable, not needed (Masahiro Yamada)
- small fix ups to selftest
- added target to main Makefile etc
- added MODULE_LICENSE to test module
- made selftest more quiet
Changes since RFC:
Both changes bring size down to 3.8MB:
- use xz for compression
- strip comments except SPDX lines
- Call out the module name in Kconfig
- Also added selftests in second patch to ensure headers are always
working.
Other notes:
By the way I still see this error (without the patch) when doing a clean
build: Makefile:594: include/config/auto.conf: No such file or directory
It appears to be because of commit 0a16d2e8cb7e ("kbuild: use 'include'
directive to load auto.conf from top Makefile")
Documentation/dontdiff | 1 +
init/Kconfig | 11 ++++++
kernel/.gitignore | 3 ++
kernel/Makefile | 36 +++++++++++++++++++
kernel/kheaders.c | 72 +++++++++++++++++++++++++++++++++++++
scripts/gen_ikh_data.sh | 76 +++++++++++++++++++++++++++++++++++++++
scripts/strip-comments.pl | 8 +++++
7 files changed, 207 insertions(+)
create mode 100644 kernel/kheaders.c
create mode 100755 scripts/gen_ikh_data.sh
create mode 100755 scripts/strip-comments.pl
diff --git a/Documentation/dontdiff b/Documentation/dontdiff
index 2228fcc8e29f..05a2319ee2a2 100644
--- a/Documentation/dontdiff
+++ b/Documentation/dontdiff
@@ -151,6 +151,7 @@ int8.c
kallsyms
kconfig
keywords.c
+kheaders_data.h*
ksym.c*
ksym.h*
kxgettext
diff --git a/init/Kconfig b/init/Kconfig
index c9386a365eea..63ff0990ae55 100644
--- a/init/Kconfig
+++ b/init/Kconfig
@@ -563,6 +563,17 @@ config IKCONFIG_PROC
This option enables access to the kernel configuration file
through /proc/config.gz.
+config IKHEADERS_PROC
+ tristate "Enable kernel header artifacts through /proc/kheaders.tar.xz"
+ select BUILD_BIN2C
+ depends on PROC_FS
+ help
+ This option enables access to the kernel header and other artifacts that
+ are generated during the build process. These can be used to build kernel
+ modules, and other in-kernel programs such as those generated by eBPF
+ and systemtap tools. If you build the headers as a module, a module
+ called kheaders.ko is built which can be loaded to get access to them.
+
config LOG_BUF_SHIFT
int "Kernel log buffer size (16 => 64KB, 17 => 128KB)"
range 12 25
diff --git a/kernel/.gitignore b/kernel/.gitignore
index b3097bde4e9c..484018945e93 100644
--- a/kernel/.gitignore
+++ b/kernel/.gitignore
@@ -3,5 +3,8 @@
#
config_data.h
config_data.gz
+kheaders.md5
+kheaders_data.h
+kheaders_data.tar.xz
timeconst.h
hz.bc
diff --git a/kernel/Makefile b/kernel/Makefile
index 6aa7543bcdb2..0bc7cacd7da6 100644
--- a/kernel/Makefile
+++ b/kernel/Makefile
@@ -70,6 +70,7 @@ obj-$(CONFIG_UTS_NS) += utsname.o
obj-$(CONFIG_USER_NS) += user_namespace.o
obj-$(CONFIG_PID_NS) += pid_namespace.o
obj-$(CONFIG_IKCONFIG) += configs.o
+obj-$(CONFIG_IKHEADERS_PROC) += kheaders.o
obj-$(CONFIG_SMP) += stop_machine.o
obj-$(CONFIG_KPROBES_SANITY_TEST) += test_kprobes.o
obj-$(CONFIG_AUDIT) += audit.o auditfilter.o
@@ -130,3 +131,38 @@ filechk_ikconfiggz = \
targets += config_data.h
$(obj)/config_data.h: $(obj)/config_data.gz FORCE
$(call filechk,ikconfiggz)
+
+# Build a list of in-kernel headers for building kernel modules
+ikh_file_list := include/
+ikh_file_list += arch/$(SRCARCH)/Makefile
+ikh_file_list += arch/$(SRCARCH)/include/
+ikh_file_list += scripts/
+ikh_file_list += Makefile
+
+# Things we need from the $objtree. "OBJDIR" is for the gen_ikh_data.sh
+# script to identify that this comes from the $objtree directory
+ikh_file_list += OBJDIR/scripts/
+ikh_file_list += OBJDIR/include/
+ikh_file_list += OBJDIR/arch/$(SRCARCH)/include/
+ifeq ($(CONFIG_STACK_VALIDATION), y)
+ikh_file_list += OBJDIR/tools/objtool/objtool
+endif
+
+$(obj)/kheaders.o: $(obj)/kheaders_data.h
+
+targets += kheaders_data.tar.xz
+
+quiet_cmd_genikh = GEN $(obj)/kheaders_data.tar.xz
+cmd_genikh = $(srctree)/scripts/gen_ikh_data.sh $@ $(ikh_file_list)
+$(obj)/kheaders_data.tar.xz: FORCE
+ $(call cmd,genikh)
+
+filechk_ikheadersxz = \
+ echo "static const char kernel_headers_data[] __used = KH_MAGIC_START"; \
+ cat $< | scripts/bin2c; \
+ echo "KH_MAGIC_END;"
+
+targets += kheaders_data.h
+targets += kheaders.md5
+$(obj)/kheaders_data.h: $(obj)/kheaders_data.tar.xz FORCE
+ $(call filechk,ikheadersxz)
diff --git a/kernel/kheaders.c b/kernel/kheaders.c
new file mode 100644
index 000000000000..46a6358301e5
--- /dev/null
+++ b/kernel/kheaders.c
@@ -0,0 +1,72 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * kernel/kheaders.c
+ * Provide headers and artifacts needed to build kernel modules.
+ * (Borrowed code from kernel/configs.c)
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/proc_fs.h>
+#include <linux/init.h>
+#include <linux/uaccess.h>
+
+/*
+ * Define kernel_headers_data and kernel_headers_data_size, which contains the
+ * compressed kernel headers. The file is first compressed with xz and then
+ * bounded by two eight byte magic numbers to allow extraction from a binary
+ * kernel image:
+ *
+ * IKHD_ST
+ * <image>
+ * IKHD_ED
+ */
+#define KH_MAGIC_START "IKHD_ST"
+#define KH_MAGIC_END "IKHD_ED"
+#include "kheaders_data.h"
+
+
+#define KH_MAGIC_SIZE (sizeof(KH_MAGIC_START) - 1)
+#define kernel_headers_data_size \
+ (sizeof(kernel_headers_data) - 1 - KH_MAGIC_SIZE * 2)
+
+static ssize_t
+ikheaders_read_current(struct file *file, char __user *buf,
+ size_t len, loff_t *offset)
+{
+ return simple_read_from_buffer(buf, len, offset,
+ kernel_headers_data + KH_MAGIC_SIZE,
+ kernel_headers_data_size);
+}
+
+static const struct file_operations ikheaders_file_ops = {
+ .read = ikheaders_read_current,
+ .llseek = default_llseek,
+};
+
+static int __init ikheaders_init(void)
+{
+ struct proc_dir_entry *entry;
+
+ /* create the current headers file */
+ entry = proc_create("kheaders.tar.xz", S_IRUGO, NULL,
+ &ikheaders_file_ops);
+ if (!entry)
+ return -ENOMEM;
+
+ proc_set_size(entry, kernel_headers_data_size);
+
+ return 0;
+}
+
+static void __exit ikheaders_cleanup(void)
+{
+ remove_proc_entry("kheaders.tar.xz", NULL);
+}
+
+module_init(ikheaders_init);
+module_exit(ikheaders_cleanup);
+
+MODULE_LICENSE("GPL v2");
+MODULE_AUTHOR("Joel Fernandes");
+MODULE_DESCRIPTION("Echo the kernel header artifacts used to build the kernel");
diff --git a/scripts/gen_ikh_data.sh b/scripts/gen_ikh_data.sh
new file mode 100755
index 000000000000..7329262bed2f
--- /dev/null
+++ b/scripts/gen_ikh_data.sh
@@ -0,0 +1,76 @@
+#!/bin/bash
+# SPDX-License-Identifier: GPL-2.0
+
+spath="$(dirname "$(readlink -f "$0")")"
+kroot="$spath/.."
+outdir="$(pwd)"
+tarfile=$1
+cpio_dir=$outdir/$tarfile.tmp
+
+src_file_list=""
+for f in $file_list; do
+ src_file_list="$src_file_list $(echo $f | grep -v OBJDIR)"
+done
+
+obj_file_list=""
+for f in $file_list; do
+ f=$(echo $f | grep OBJDIR | sed -e 's/OBJDIR\///g')
+ obj_file_list="$obj_file_list $f";
+done
+
+# Support incremental builds by skipping archive generation
+# if timestamps of files being archived are not changed.
+
+# This block is useful for debugging the incremental builds.
+# Uncomment it for debugging.
+# iter=1
+# if [ ! -f /tmp/iter ]; then echo 1 > /tmp/iter;
+# else; iter=$(($(cat /tmp/iter) + 1)); fi
+# find $src_file_list -type f | xargs ls -lR > /tmp/src-ls-$iter
+# find $obj_file_list -type f | xargs ls -lR > /tmp/obj-ls-$iter
+
+# modules.order and include/generated/compile.h are ignored because these are
+# touched even when none of the source files changed. This causes pointless
+# regeneration, so let us ignore them for md5 calculation.
+pushd $kroot > /dev/null
+src_files_md5="$(find $src_file_list -type f ! -name modules.order |
+ grep -v "include/generated/compile.h" |
+ xargs ls -lR | md5sum | cut -d ' ' -f1)"
+popd > /dev/null
+obj_files_md5="$(find $obj_file_list -type f ! -name modules.order |
+ grep -v "include/generated/compile.h" |
+ xargs ls -lR | md5sum | cut -d ' ' -f1)"
+
+if [ -f $tarfile ]; then tarfile_md5="$(md5sum $tarfile | cut -d ' ' -f1)"; fi
+if [ -f kernel/kheaders.md5 ] &&
+ [ "$(cat kernel/kheaders.md5|head -1)" == "$src_files_md5" ] &&
+ [ "$(cat kernel/kheaders.md5|head -2|tail -1)" == "$obj_files_md5" ] &&
+ [ "$(cat kernel/kheaders.md5|tail -1)" == "$tarfile_md5" ]; then
+ exit
+fi
+
+rm -rf $cpio_dir
+mkdir $cpio_dir
+
+pushd $kroot > /dev/null
+for f in $src_file_list;
+ do find "$f" ! -name "*.c" ! -name "*.o" ! -name "*.cmd" ! -name ".*";
+done | cpio --quiet -pd $cpio_dir
+popd > /dev/null
+
+# The second CPIO can complain if files already exist which can
+# happen with out of tree builds. Just silence CPIO for now.
+for f in $obj_file_list;
+ do find "$f" ! -name "*.c" ! -name "*.o" ! -name "*.cmd" ! -name ".*";
+done | cpio --quiet -pd $cpio_dir >/dev/null 2>&1
+
+find $cpio_dir -type f -print0 |
+ xargs -0 -P8 -n1 -I {} sh -c "$spath/strip-comments.pl {}"
+
+tar -Jcf $tarfile -C $cpio_dir/ . > /dev/null
+
+echo "$src_files_md5" > kernel/kheaders.md5
+echo "$obj_files_md5" >> kernel/kheaders.md5
+echo "$(md5sum $tarfile | cut -d ' ' -f1)" >> kernel/kheaders.md5
+
+rm -rf $cpio_dir
diff --git a/scripts/strip-comments.pl b/scripts/strip-comments.pl
new file mode 100755
index 000000000000..f8ada87c5802
--- /dev/null
+++ b/scripts/strip-comments.pl
@@ -0,0 +1,8 @@
+#!/usr/bin/perl -pi
+# SPDX-License-Identifier: GPL-2.0
+
+# This script removes /**/ comments from a file, unless such comments
+# contain "SPDX". It is used when building compressed in-kernel headers.
+
+BEGIN {undef $/;}
+s/\/\*((?!SPDX).)*?\*\///smg;
--
2.21.0.rc2.261.ga7da99ff1b-goog