If you wish to utilise a pidfd interface to refer to the current process or
thread it is rather cumbersome, requiring something like:
int pidfd = pidfd_open(getpid(), 0 or PIDFD_THREAD);
...
close(pidfd);
Or the equivalent call opening /proc/self. It is more convenient to use a
sentinel value to indicate to an interface that accepts a pidfd that we
simply wish to refer to the current process thread.
This series introduces sentinels for this purposes which can be passed as
the pidfd in this instance rather than having to establish a dummy fd for
this purpose.
It is useful to refer to both the current thread from the userland's
perspective for which we use PIDFD_SELF, and the current process from the
userland's perspective, for which we use PIDFD_SELF_PROCESS.
There is unfortunately some confusion between the kernel and userland as to
what constitutes a process - a thread from the userland perspective is a
process in userland, and a userland process is a thread group (more
specifically the thread group leader from the kernel perspective). We
therefore alias things thusly:
* PIDFD_SELF_THREAD aliased by PIDFD_SELF - use PIDTYPE_PID.
* PIDFD_SELF_THREAD_GROUP alised by PIDFD_SELF_PROCESS - use PIDTYPE_TGID.
In all of the kernel code we refer to PIDFD_SELF_THREAD and
PIDFD_SELF_THREAD_GROUP. However we expect users to use PIDFD_SELF and
PIDFD_SELF_PROCESS.
This matters for cases where, for instance, a user unshare()'s FDs or does
thread-specific signal handling and where the user would be hugely confused
if the FDs referenced or signal processed referred to the thread group
leader rather than the individual thread.
We ensure that pidfd_send_signal() and pidfd_getfd() work correctly, and
assert as much in selftests. All other interfaces except setns() will work
implicitly with this new interface, however it doesn't make sense to test
waitid(P_PIDFD, ...) as waiting on ourselves is a blocking operation.
In the case of setns() we explicitly disallow use of PIDFD_SELF* as it
doesn't make sense to obtain the namespaces of our own process, and it
would require work to implement this functionality there that would be of
no use.
We also do not provide the ability to utilise PIDFD_SELF* in ordinary fd
operations such as open() or poll(), as this would require extensive work
and be of no real use.
v4:
* Avoid returning an fd in the __pidfd_get_pid() function as pointed out by
Christian, instead simply always pin the pid and maintain fd scope in the
helper alone.
* Add wrapper header file in tools/include/linux to allow for import of
UAPI pidfd.h header without encountering the collision between system
fcntl.h and linux/fcntl.h as discussed with Shuah and John.
* Fixup tests to import the UAPI pidfd.h header working around conflicts
between system fcntl.h and linux/fcntl.h which the UAPI pidfd.h imports,
as reported by Shuah.
* Use an int for pidfd_is_self_sentinel() to avoid any dependency on
stdbool.h in userland.
v3:
* Do not fput() an invalid fd as reported by kernel test bot.
* Fix unintended churn from moving variable declaration.
https://lore.kernel.org/linux-mm/cover.1729073310.git.lorenzo.stoakes@oracl…
v2:
* Fix tests as reported by Shuah.
* Correct RFC version lore link.
https://lore.kernel.org/linux-mm/cover.1728643714.git.lorenzo.stoakes@oracl…
Non-RFC v1:
* Removed RFC tag - there seems to be general consensus that this change is
a good idea, but perhaps some debate to be had on implementation. It
seems sensible then to move forward with the RFC flag removed.
* Introduced PIDFD_SELF_THREAD, PIDFD_SELF_THREAD_GROUP and their aliases
PIDFD_SELF and PIDFD_SELF_PROCESS respectively.
* Updated testing accordingly.
https://lore.kernel.org/linux-mm/cover.1728578231.git.lorenzo.stoakes@oracl…
RFC version:
https://lore.kernel.org/linux-mm/cover.1727644404.git.lorenzo.stoakes@oracl…
Lorenzo Stoakes (4):
pidfd: extend pidfd_get_pid() and de-duplicate pid lookup
pidfd: add PIDFD_SELF_* sentinels to refer to own thread/process
selftests: pidfd: add pidfd.h UAPI wrapper
selftests: pidfd: add tests for PIDFD_SELF_*
include/linux/pid.h | 34 ++++-
include/uapi/linux/pidfd.h | 15 ++
kernel/exit.c | 3 +-
kernel/nsproxy.c | 1 +
kernel/pid.c | 65 +++++---
kernel/signal.c | 29 +---
tools/include/linux/pidfd.h | 14 ++
tools/testing/selftests/pidfd/Makefile | 3 +-
tools/testing/selftests/pidfd/pidfd.h | 2 +
.../selftests/pidfd/pidfd_getfd_test.c | 141 ++++++++++++++++++
.../selftests/pidfd/pidfd_setns_test.c | 11 ++
tools/testing/selftests/pidfd/pidfd_test.c | 76 ++++++++--
12 files changed, 333 insertions(+), 61 deletions(-)
create mode 100644 tools/include/linux/pidfd.h
--
2.46.2
RISC-V defines three extensions for pointer masking[1]:
- Smmpm: configured in M-mode, affects M-mode
- Smnpm: configured in M-mode, affects the next lower mode (S or U-mode)
- Ssnpm: configured in S-mode, affects the next lower mode (VS, VU, or U-mode)
This series adds support for configuring Smnpm or Ssnpm (depending on
which privilege mode the kernel is running in) to allow pointer masking
in userspace (VU or U-mode), extending the PR_SET_TAGGED_ADDR_CTRL API
from arm64. Unlike arm64 TBI, userspace pointer masking is not enabled
by default on RISC-V. Additionally, the tag width (referred to as PMLEN)
is variable, so userspace needs to ask the kernel for a specific tag
width, which is interpreted as a lower bound on the number of tag bits.
This series also adds support for a tagged address ABI similar to arm64
and x86. Since accesses from the kernel to user memory use the kernel's
pointer masking configuration, not the user's, the kernel must untag
user pointers in software before dereferencing them. And since the tag
width is variable, as with LAM on x86, it must be kept the same across
all threads in a process so untagged_addr_remote() can work.
[1]: https://github.com/riscv/riscv-j-extension/raw/d70011dde6c2/zjpm-spec.pdf
---
This series depends on the per-thread envcfg series in riscv/for-next.
This series can be tested in QEMU by applying a patch set[2].
KASAN_SW_TAGS using pointer masking is an independent patch series[3].
[2]: https://lore.kernel.org/qemu-devel/20240511101053.1875596-1-me@deliversmonk…
[3]: https://lore.kernel.org/linux-riscv/20240814085618.968833-1-samuel.holland@…
Changes in v5:
- Update pointer masking spec version to 1.0 and state to ratified
- Document how PR_[SG]ET_TAGGED_ADDR_CTRL are used on RISC-V
- Document that the RISC-V tagged address ABI is the same as AArch64
- Rename "pm" selftests directory to "abi" to be more generic
- Fix -Wparentheses warnings
- Fix order of operations when writing via the tagged pointer
- Update pointer masking spec version to 1.0 in hwprobe documentation
Changes in v4:
- Switch IS_ENABLED back to #ifdef to fix riscv32 build
- Combine __untagged_addr() and __untagged_addr_remote()
Changes in v3:
- Note in the commit message that the ISA extension spec is frozen
- Rebase on riscv/for-next (ISA extension list conflicts)
- Remove RISCV_ISA_EXT_SxPM, which was not used anywhere
- Use shifts instead of large numbers in ENVCFG_PMM* macro definitions
- Rename CONFIG_RISCV_ISA_POINTER_MASKING to CONFIG_RISCV_ISA_SUPM,
since it only controls the userspace part of pointer masking
- Use IS_ENABLED instead of #ifdef when possible
- Use an enum for the supported PMLEN values
- Simplify the logic in set_tagged_addr_ctrl()
- Use IS_ENABLED instead of #ifdef when possible
- Implement mm_untag_mask()
- Remove pmlen from struct thread_info (now only in mm_context_t)
Changes in v2:
- Drop patch 4 ("riscv: Define is_compat_thread()"), as an equivalent
patch was already applied
- Move patch 5 ("riscv: Split per-CPU and per-thread envcfg bits") to a
different series[3]
- Update pointer masking specification version reference
- Provide macros for the extension affecting the kernel and userspace
- Use the correct name for the hstatus.HUPMM field
- Rebase on riscv/linux.git for-next
- Add and use the envcfg_update_bits() helper function
- Inline flush_tagged_addr_state()
- Implement untagged_addr_remote()
- Restrict PMLEN changes once a process is multithreaded
- Rename "tags" directory to "pm" to avoid .gitignore rules
- Add .gitignore file to ignore the compiled selftest binary
- Write to a pipe to force dereferencing the user pointer
- Handle SIGSEGV in the child process to reduce dmesg noise
- Export Supm via hwprobe
- Export Smnpm and Ssnpm to KVM guests
Samuel Holland (10):
dt-bindings: riscv: Add pointer masking ISA extensions
riscv: Add ISA extension parsing for pointer masking
riscv: Add CSR definitions for pointer masking
riscv: Add support for userspace pointer masking
riscv: Add support for the tagged address ABI
riscv: Allow ptrace control of the tagged address ABI
riscv: selftests: Add a pointer masking test
riscv: hwprobe: Export the Supm ISA extension
RISC-V: KVM: Allow Smnpm and Ssnpm extensions for guests
KVM: riscv: selftests: Add Smnpm and Ssnpm to get-reg-list test
Documentation/arch/riscv/hwprobe.rst | 3 +
Documentation/arch/riscv/uabi.rst | 16 +
.../devicetree/bindings/riscv/extensions.yaml | 18 +
arch/riscv/Kconfig | 11 +
arch/riscv/include/asm/csr.h | 16 +
arch/riscv/include/asm/hwcap.h | 5 +
arch/riscv/include/asm/mmu.h | 7 +
arch/riscv/include/asm/mmu_context.h | 13 +
arch/riscv/include/asm/processor.h | 8 +
arch/riscv/include/asm/switch_to.h | 11 +
arch/riscv/include/asm/uaccess.h | 43 ++-
arch/riscv/include/uapi/asm/hwprobe.h | 1 +
arch/riscv/include/uapi/asm/kvm.h | 2 +
arch/riscv/kernel/cpufeature.c | 3 +
arch/riscv/kernel/process.c | 154 ++++++++
arch/riscv/kernel/ptrace.c | 42 +++
arch/riscv/kernel/sys_hwprobe.c | 3 +
arch/riscv/kvm/vcpu_onereg.c | 4 +
include/uapi/linux/elf.h | 1 +
include/uapi/linux/prctl.h | 5 +-
.../selftests/kvm/riscv/get-reg-list.c | 8 +
tools/testing/selftests/riscv/Makefile | 2 +-
tools/testing/selftests/riscv/abi/.gitignore | 1 +
tools/testing/selftests/riscv/abi/Makefile | 10 +
.../selftests/riscv/abi/pointer_masking.c | 332 ++++++++++++++++++
25 files changed, 712 insertions(+), 7 deletions(-)
create mode 100644 tools/testing/selftests/riscv/abi/.gitignore
create mode 100644 tools/testing/selftests/riscv/abi/Makefile
create mode 100644 tools/testing/selftests/riscv/abi/pointer_masking.c
--
2.45.1
This series was motivated by the regression fixed by 166bf8af9122
("pinctrl: mediatek: common-v2: Fix broken bias-disable for
PULL_PU_PD_RSEL_TYPE"). A bug was introduced in the pinctrl_paris driver
which prevented certain pins from having their bias configured.
Running this test on the mt8195-tomato platform with the test plan
included below[1] shows the test passing with the fix applied, but failing
without the fix:
With fix:
$ ./gpio-setget-config.py
TAP version 13
# Using test plan file: ./google,tomato.yaml
1..3
ok 1 pinctrl_paris.34.pull-up
ok 2 pinctrl_paris.34.pull-down
ok 3 pinctrl_paris.34.disabled
# Totals: pass:3 fail:0 xfail:0 xpass:0 skip:0 error:0
Without fix:
$ ./gpio-setget-config.py
TAP version 13
# Using test plan file: ./google,tomato.yaml
1..3
# Bias doesn't match: Expected pull-up, read pull-down.
not ok 1 pinctrl_paris.34.pull-up
ok 2 pinctrl_paris.34.pull-down
# Bias doesn't match: Expected disabled, read pull-down.
not ok 3 pinctrl_paris.34.disabled
# Totals: pass:1 fail:2 xfail:0 xpass:0 skip:0 error:0
In order to achieve this, the first patch exposes bias configuration
through the GPIO API in the pinctrl_paris driver, patch 2 extends the
gpio-mockup-cdev utility for use by patch 3, and patch 3 introduces a
new GPIO kselftest that takes a test plan in YAML, which can be tailored
per-platform to specify the configurations to test, and sets and gets
back each pin configuration to verify that they match and thus that the
driver is behaving as expected.
Since the GPIO uAPI only allows setting the pin configuration, getting
it back is done through pinconf-pins in the pinctrl debugfs folder.
The test currently only verifies bias but it would be easy to extend to
verify other pin configurations.
The test plan YAML file can be customized for each use-case and is
platform-dependant. For that reason, only an example is included in
patch 3 and the user is supposed to provide their test plan. That said,
the aim is to collect test plans for ease of use at [2].
[1] This is the test plan used for mt8195-tomato:
- label: "pinctrl_paris"
tests:
# Pin 34 has type MTK_PULL_PU_PD_RSEL_TYPE and is unused.
# Setting bias to MTK_PULL_PU_PD_RSEL_TYPE pins was fixed by
# 166bf8af9122 ("pinctrl: mediatek: common-v2: Fix broken bias-disable for PULL_PU_PD_RSEL_TYPE")
- pin: 34
bias: "pull-up"
- pin: 34
bias: "pull-down"
- pin: 34
bias: "disabled"
[2] https://github.com/kernelci/platform-test-parameters
Signed-off-by: Nícolas F. R. A. Prado <nfraprado(a)collabora.com>
---
Nícolas F. R. A. Prado (3):
pinctrl: mediatek: paris: Expose more configurations to GPIO set_config
selftest: gpio: Add wait flag to gpio-mockup-cdev
selftest: gpio: Add a new set-get config test
drivers/pinctrl/mediatek/pinctrl-paris.c | 20 +--
tools/testing/selftests/gpio/Makefile | 2 +-
tools/testing/selftests/gpio/gpio-mockup-cdev.c | 14 +-
.../gpio-set-get-config-example-test-plan.yaml | 15 ++
.../testing/selftests/gpio/gpio-set-get-config.py | 183 +++++++++++++++++++++
5 files changed, 220 insertions(+), 14 deletions(-)
---
base-commit: 6a7917c89f219f09b1d88d09f376000914a52763
change-id: 20240906-kselftest-gpio-set-get-config-6e5bb670c1a5
Best regards,
--
Nícolas F. R. A. Prado <nfraprado(a)collabora.com>
For logging to be useful, something has to set RET and retmsg by calling
ret_set_ksft_status(). There is a suite of functions to that end in
forwarding/lib: check_err, check_fail et.al. Move them to net/lib.sh so
that every net test can use them.
Existing lib.sh users might be using these same names for their functions.
However lib.sh is always sourced near the top of the file (checked), and
whatever new definitions will simply override the ones provided by lib.sh.
Signed-off-by: Petr Machata <petrm(a)nvidia.com>
Reviewed-by: Amit Cohen <amcohen(a)nvidia.com>
Acked-by: Shuah Khan <skhan(a)linuxfoundation.org>
---
Notes:
CC: Shuah Khan <shuah(a)kernel.org>
CC: Benjamin Poirier <bpoirier(a)nvidia.com>
CC: Hangbin Liu <liuhangbin(a)gmail.com>
CC: linux-kselftest(a)vger.kernel.org
CC: Jiri Pirko <jiri(a)resnulli.us>
---
tools/testing/selftests/net/forwarding/lib.sh | 73 -------------------
tools/testing/selftests/net/lib.sh | 73 +++++++++++++++++++
2 files changed, 73 insertions(+), 73 deletions(-)
diff --git a/tools/testing/selftests/net/forwarding/lib.sh b/tools/testing/selftests/net/forwarding/lib.sh
index d28dbf27c1f0..8625e3c99f55 100644
--- a/tools/testing/selftests/net/forwarding/lib.sh
+++ b/tools/testing/selftests/net/forwarding/lib.sh
@@ -445,79 +445,6 @@ done
##############################################################################
# Helpers
-# Whether FAILs should be interpreted as XFAILs. Internal.
-FAIL_TO_XFAIL=
-
-check_err()
-{
- local err=$1
- local msg=$2
-
- if ((err)); then
- if [[ $FAIL_TO_XFAIL = yes ]]; then
- ret_set_ksft_status $ksft_xfail "$msg"
- else
- ret_set_ksft_status $ksft_fail "$msg"
- fi
- fi
-}
-
-check_fail()
-{
- local err=$1
- local msg=$2
-
- check_err $((!err)) "$msg"
-}
-
-check_err_fail()
-{
- local should_fail=$1; shift
- local err=$1; shift
- local what=$1; shift
-
- if ((should_fail)); then
- check_fail $err "$what succeeded, but should have failed"
- else
- check_err $err "$what failed"
- fi
-}
-
-xfail()
-{
- FAIL_TO_XFAIL=yes "$@"
-}
-
-xfail_on_slow()
-{
- if [[ $KSFT_MACHINE_SLOW = yes ]]; then
- FAIL_TO_XFAIL=yes "$@"
- else
- "$@"
- fi
-}
-
-omit_on_slow()
-{
- if [[ $KSFT_MACHINE_SLOW != yes ]]; then
- "$@"
- fi
-}
-
-xfail_on_veth()
-{
- local dev=$1; shift
- local kind
-
- kind=$(ip -j -d link show dev $dev |
- jq -r '.[].linkinfo.info_kind')
- if [[ $kind = veth ]]; then
- FAIL_TO_XFAIL=yes "$@"
- else
- "$@"
- fi
-}
-
not()
{
"$@"
diff --git a/tools/testing/selftests/net/lib.sh b/tools/testing/selftests/net/lib.sh
index 4f52b8e48a3a..6bcf5d13879d 100644
--- a/tools/testing/selftests/net/lib.sh
+++ b/tools/testing/selftests/net/lib.sh
@@ -361,3 +361,76 @@ tests_run()
$current_test
done
}
+
+# Whether FAILs should be interpreted as XFAILs. Internal.
+FAIL_TO_XFAIL=
+
+check_err()
+{
+ local err=$1
+ local msg=$2
+
+ if ((err)); then
+ if [[ $FAIL_TO_XFAIL = yes ]]; then
+ ret_set_ksft_status $ksft_xfail "$msg"
+ else
+ ret_set_ksft_status $ksft_fail "$msg"
+ fi
+ fi
+}
+
+check_fail()
+{
+ local err=$1
+ local msg=$2
+
+ check_err $((!err)) "$msg"
+}
+
+check_err_fail()
+{
+ local should_fail=$1; shift
+ local err=$1; shift
+ local what=$1; shift
+
+ if ((should_fail)); then
+ check_fail $err "$what succeeded, but should have failed"
+ else
+ check_err $err "$what failed"
+ fi
+}
+
+xfail()
+{
+ FAIL_TO_XFAIL=yes "$@"
+}
+
+xfail_on_slow()
+{
+ if [[ $KSFT_MACHINE_SLOW = yes ]]; then
+ FAIL_TO_XFAIL=yes "$@"
+ else
+ "$@"
+ fi
+}
+
+omit_on_slow()
+{
+ if [[ $KSFT_MACHINE_SLOW != yes ]]; then
+ "$@"
+ fi
+}
+
+xfail_on_veth()
+{
+ local dev=$1; shift
+ local kind
+
+ kind=$(ip -j -d link show dev $dev |
+ jq -r '.[].linkinfo.info_kind')
+ if [[ $kind = veth ]]; then
+ FAIL_TO_XFAIL=yes "$@"
+ else
+ "$@"
+ fi
+}
--
2.45.0
It would be good to use the same mechanism for scheduling and dispatching
general net tests as the many forwarding tests already use. To that end,
move the logging helpers to net/lib.sh so that every net test can use them.
Existing lib.sh users might be using the name themselves. However lib.sh is
always sourced near the top of the file (checked), and whatever new
definition will simply override the one provided by lib.sh.
Signed-off-by: Petr Machata <petrm(a)nvidia.com>
Reviewed-by: Amit Cohen <amcohen(a)nvidia.com>
Acked-by: Shuah Khan <skhan(a)linuxfoundation.org>
---
Notes:
CC: Shuah Khan <shuah(a)kernel.org>
CC: Benjamin Poirier <bpoirier(a)nvidia.com>
CC: Hangbin Liu <liuhangbin(a)gmail.com>
CC: linux-kselftest(a)vger.kernel.org
CC: Jiri Pirko <jiri(a)resnulli.us>
---
tools/testing/selftests/net/forwarding/lib.sh | 10 ----------
tools/testing/selftests/net/lib.sh | 10 ++++++++++
2 files changed, 10 insertions(+), 10 deletions(-)
diff --git a/tools/testing/selftests/net/forwarding/lib.sh b/tools/testing/selftests/net/forwarding/lib.sh
index 41dd14c42c48..d28dbf27c1f0 100644
--- a/tools/testing/selftests/net/forwarding/lib.sh
+++ b/tools/testing/selftests/net/forwarding/lib.sh
@@ -1285,16 +1285,6 @@ matchall_sink_create()
action drop
}
-tests_run()
-{
- local current_test
-
- for current_test in ${TESTS:-$ALL_TESTS}; do
- in_defer_scope \
- $current_test
- done
-}
-
cleanup()
{
pre_cleanup
diff --git a/tools/testing/selftests/net/lib.sh b/tools/testing/selftests/net/lib.sh
index 691318b1ec55..4f52b8e48a3a 100644
--- a/tools/testing/selftests/net/lib.sh
+++ b/tools/testing/selftests/net/lib.sh
@@ -351,3 +351,13 @@ log_info()
echo "INFO: $msg"
}
+
+tests_run()
+{
+ local current_test
+
+ for current_test in ${TESTS:-$ALL_TESTS}; do
+ in_defer_scope \
+ $current_test
+ done
+}
--
2.45.0