commit 4f79eaa2ce upstream.
Clang and GCC have different behaviors around disabling warnings
included in -Wall and -Wextra and the order in which flags are
specified, which is exposed by clang's new support for
-Wunterminated-string-initialization.
$ cat test.c
const char foo[3] = "FOO";
const char bar[3] __attribute__((__nonstring__)) = "BAR";
$ clang -fsyntax-only -Wextra test.c
test.c:1:21: warning: initializer-string for character array is too long, array size is 3 but initializer has size 4 (including the null terminating character); did you mean to use the 'nonstring' attribute? [-Wunterminated-string-initialization]
1 | const char foo[3] = "FOO";
| ^~~~~
$ clang -fsyntax-only -Wextra -Wno-unterminated-string-initialization test.c
$ clang -fsyntax-only -Wno-unterminated-string-initialization -Wextra test.c
test.c:1:21: warning: initializer-string for character array is too long, array size is 3 but initializer has size 4 (including the null terminating character); did you mean to use the 'nonstring' attribute? [-Wunterminated-string-initialization]
1 | const char foo[3] = "FOO";
| ^~~~~
$ gcc -fsyntax-only -Wextra test.c
test.c:1:21: warning: initializer-string for array of ‘char’ truncates NUL terminator but destination lacks ‘nonstring’ attribute (4 chars into 3 available) [-Wunterminated-string-initialization]
1 | const char foo[3] = "FOO";
| ^~~~~
$ gcc -fsyntax-only -Wextra -Wno-unterminated-string-initialization test.c
$ gcc -fsyntax-only -Wno-unterminated-string-initialization -Wextra test.c
Move -Wextra up right below -Wall in Makefile.extrawarn to ensure these
flags are at the beginning of the warning options list. Move the couple
of warning options that have been added to the main Makefile since
commit e88ca24319 ("kbuild: consolidate warning flags in
scripts/Makefile.extrawarn") to scripts/Makefile.extrawarn after -Wall /
-Wextra to ensure they get properly disabled for all compilers.
Fixes: 9d7a0577c9 ("gcc-15: disable '-Wunterminated-string-initialization' entirely for now")
Link: https://github.com/llvm/llvm-project/issues/10359
Signed-off-by: Nathan Chancellor <nathan@kernel.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Nathan Chancellor <nathan@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit a79be02bba upstream.
This was triggered by one of my mis-uses causing odd build warnings on
sparc in linux-next, but while figuring out why the "obviously correct"
use of cc-option caused such odd breakage, I found eight other cases of
the same thing in the tree.
The root cause is that 'cc-option' doesn't work for checking negative
warning options (ie things like '-Wno-stringop-overflow') because gcc
will silently accept options it doesn't recognize, and so 'cc-option'
ends up thinking they are perfectly fine.
And it all works, until you have a situation where _another_ warning is
emitted. At that point the compiler will go "Hmm, maybe the user
intended to disable this warning but used that wrong option that I
didn't recognize", and generate a warning for the unrecognized negative
option.
Which explains why we have several cases of this in the tree: the
'cc-option' test really doesn't work for this situation, but most of the
time it simply doesn't matter that ity doesn't work.
The reason my recently added case caused problems on sparc was pointed
out by Thomas Weißschuh: the sparc build had a previous explicit warning
that then triggered the new one.
I think the best fix for this would be to make 'cc-option' a bit smarter
about this sitation, possibly by adding an intentional warning to the
test case that then triggers the unrecognized option warning reliably.
But the short-term fix is to replace 'cc-option' with an existing helper
designed for this exact case: 'cc-disable-warning', which picks the
negative warning but uses the positive form for testing the compiler
support.
Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Link: https://lore.kernel.org/all/20250422204718.0b4e3f81@canb.auug.org.au/
Explained-by: Thomas Weißschuh <linux@weissschuh.net>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Nathan Chancellor <nathan@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 9d7a0577c9 upstream.
I had left the warning around but as a non-fatal error to get my gcc-15
builds going, but fixed up some of the most annoying warning cases so
that it wouldn't be *too* verbose.
Because I like the _concept_ of the warning, even if I detested the
implementation to shut it up.
It turns out the implementation to shut it up is even more broken than I
thought, and my "shut up most of the warnings" patch just caused fatal
errors on gcc-14 instead.
I had tested with clang, but when I upgrade my development environment,
I try to do it on all machines because I hate having different systems
to maintain, and hadn't realized that gcc-14 now had issues.
The ACPI case is literally why I wanted to have a *type* that doesn't
trigger the warning (see commit d5d45a7f26: "gcc-15: make
'unterminated string initialization' just a warning"), instead of
marking individual places as "__nonstring".
But gcc-14 doesn't like that __nonstring location that shut gcc-15 up,
because it's on an array of char arrays, not on one single array:
drivers/acpi/tables.c:399:1: error: 'nonstring' attribute ignored on objects of type 'const char[][4]' [-Werror=attributes]
399 | static const char table_sigs[][ACPI_NAMESEG_SIZE] __initconst __nonstring = {
| ^~~~~~
and my attempts to nest it properly with a type had failed, because of
how gcc doesn't like marking the types as having attributes, only
symbols.
There may be some trick to it, but I was already annoyed by the bad
attribute design, now I'm just entirely fed up with it.
I wish gcc had a proper way to say "this type is a *byte* array, not a
string".
The obvious thing would be to distinguish between "char []" and an
explicitly signed "unsigned char []" (as opposed to an implicitly
unsigned char, which is typically an architecture-specific default, but
for the kernel is universal thanks to '-funsigned-char').
But any "we can typedef a 8-bit type to not become a string just because
it's an array" model would be fine.
But "__attribute__((nonstring))" is sadly not that sane model.
Reported-by: Chris Clayton <chris2553@googlemail.com>
Fixes: 4b4bd8c50f ("gcc-15: acpi: sprinkle random '__nonstring' crumbles around")
Fixes: d5d45a7f26 ("gcc-15: make 'unterminated string initialization' just a warning")
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
[nathan: drivers/acpi diff dropped due to lack of 4b4bd8c50f in stable]
Signed-off-by: Nathan Chancellor <nathan@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit d5d45a7f26 upstream.
gcc-15 enabling -Wunterminated-string-initialization in -Wextra by
default was done with the best intentions, but the warning is still
quite broken.
What annoys me about the warning is that this is a very traditional AND
CORRECT way to initialize fixed byte arrays in C:
unsigned char hex[16] = "0123456789abcdef";
and we use this all over the kernel. And the warning is fine, but gcc
developers apparently never made a reasonable way to disable it. As is
(sadly) tradition with these things.
Yes, there's "__attribute__((nonstring))", and we have a macro to make
that absolutely disgusting syntax more palatable (ie the kernel syntax
for that monstrosity is just "__nonstring").
But that attribute is misdesigned. What you'd typically want to do is
tell the compiler that you are using a type that isn't a string but a
byte array, but that doesn't work at all:
warning: ‘nonstring’ attribute does not apply to types [-Wattributes]
and because of this fundamental mis-design, you then have to mark each
instance of that pattern.
This is particularly noticeable in our ACPI code, because ACPI has this
notion of a 4-byte "type name" that gets used all over, and is exactly
this kind of byte array.
This is a sad oversight, because the warning is useful, but really would
be so much better if gcc had also given a sane way to indicate that we
really just want a byte array type at a type level, not the broken "each
and every array definition" level.
So now instead of creating a nice "ACPI name" type using something like
typedef char acpi_name_t[4] __nonstring;
we have to do things like
char name[ACPI_NAMESEG_SIZE] __nonstring;
in every place that uses this concept and then happens to have the
typical initializers.
This is annoying me mainly because I think the warning _is_ a good
warning, which is why I'm not just turning it off in disgust. But it is
hampered by this bad implementation detail.
[ And obviously I'm doing this now because system upgrades for me are
something that happen in the middle of the release cycle: don't do it
before or during travel, or just before or during the busy merge
window period. ]
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Nathan Chancellor <nathan@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 8cf5b3f836 upstream.
This reverts commit dbdffaf50f.
--remap-path-prefix breaks the ability of debuggers to find the source
file corresponding to object files. As there is no simple or uniform
way to specify the source directory explicitly, this breaks developers
workflows.
Revert the unconditional usage of --remap-path-prefix, equivalent to the
same change for -ffile-prefix-map in KBUILD_CPPFLAGS.
Fixes: dbdffaf50f ("kbuild, rust: use -fremap-path-prefix to make paths relative")
Signed-off-by: Thomas Weißschuh <linux@weissschuh.net>
Acked-by: Miguel Ojeda <ojeda@kernel.org>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 0866ee8e50 upstream.
Starting with Rust 1.86.0, Clippy's `needless_continue` lint complains
about the last statement of a loop [1], including cases like:
while ... {
match ... {
... if ... => {
...
return ...;
}
_ => continue,
}
}
as well as nested `match`es in a loop.
One solution is changing `continue` for `()` [2], but arguably using
`continue` shows the intent better when it is alone in an arm like that.
Moreover, I am not sure we want to force people to try to find other
ways to write the code either, in cases when that applies.
In addition, the help text does not really apply in the new cases the
lint has introduced, e.g. here one cannot simply "drop" the expression:
warning: this `continue` expression is redundant
--> rust/macros/helpers.rs:85:18
|
85 | _ => continue,
| ^^^^^^^^
|
= help: consider dropping the `continue` expression
= help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#needless_continue
= note: requested on the command line with `-W clippy::needless-continue`
The examples in the documentation do not show a case like this, either,
so the second "help" line does not help.
In addition, locally disabling the lint is not possible with `expect`,
since the behavior differs across versions. Using `allow` would be
possible, but, even then, an extra line just for this is a bit too much,
especially if there are other ways to satisfy the lint.
Finally, the lint is still in the "pedantic" category and disabled by
default by Clippy.
Thus disable the lint, at least for the time being.
Feedback was submitted to upstream Clippy, in case this can be improved
or perhaps the lint split into several [3].
Cc: stable@vger.kernel.org # Needed in 6.12.y and later (Rust is pinned in older LTSs).
Link: https://github.com/rust-lang/rust-clippy/pull/13891 [1]
Link: https://lore.kernel.org/rust-for-linux/20250401221205.52381-1-ojeda@kernel.org/ [2]
Link: https://github.com/rust-lang/rust-clippy/issues/14536 [3]
Link: https://lore.kernel.org/r/20250403163805.67770-1-ojeda@kernel.org
Reviewed-by: Alice Ryhl <aliceryhl@google.com>
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 84ffc79bfb upstream.
A recent optimization change in LLVM [1] aims to transform certain loop
idioms into calls to strlen() or wcslen(). This change transforms the
first while loop in UniStrcat() into a call to wcslen(), breaking the
build when UniStrcat() gets inlined into alloc_path_with_tree_prefix():
ld.lld: error: undefined symbol: wcslen
>>> referenced by nls_ucs2_utils.h:54 (fs/smb/client/../../nls/nls_ucs2_utils.h:54)
>>> vmlinux.o:(alloc_path_with_tree_prefix)
>>> referenced by nls_ucs2_utils.h:54 (fs/smb/client/../../nls/nls_ucs2_utils.h:54)
>>> vmlinux.o:(alloc_path_with_tree_prefix)
Disable this optimization with '-fno-builtin-wcslen', which prevents the
compiler from assuming that wcslen() is available in the kernel's C
library.
[ More to the point - it's not that we couldn't implement wcslen(), it's
that this isn't an optimization at all in the context of the kernel.
Replacing a simple inlined loop with a function call to the same loop
is just stupid and pointless if you don't have long strings and fancy
libraries with vectorization support etc.
For the regular 'strlen()' cases, we want the compiler to do this in
order to handle the trivial case of constant strings. And we do have
optimized versions of 'strlen()' on some architectures. But for
wcslen? Just no. - Linus ]
Cc: stable@vger.kernel.org
Link: 9694844d7e [1]
Signed-off-by: Nathan Chancellor <nathan@kernel.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The userprog infrastructure links objects files through $(CC).
Either explicitly by manually calling $(CC) on multiple object files or
implicitly by directly compiling a source file to an executable.
The documentation at Documentation/kbuild/llvm.rst indicates that ld.lld
would be used for linking if LLVM=1 is specified.
However clang instead will use either a globally installed cross linker
from $PATH called ${target}-ld or fall back to the system linker, which
probably does not support crosslinking.
For the normal kernel build this is not an issue because the linker is
always executed directly, without the compiler being involved.
Explicitly pass --ld-path to clang so $(LD) is respected.
As clang 13.0.1 is required to build the kernel, this option is available.
Fixes: 7f3a59db27 ("kbuild: add infrastructure to build userspace programs")
Cc: stable@vger.kernel.org # needs wrapping in $(cc-option) for < 6.9
Signed-off-by: Thomas Weißschuh <thomas.weissschuh@linutronix.de>
Reviewed-by: Nathan Chancellor <nathan@kernel.org>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
scripts/Makefile.clang was changed in the linked commit to move --target from
KBUILD_CFLAGS to KBUILD_CPPFLAGS, as that generally has a broader scope.
However that variable is not inspected by the userprogs logic,
breaking cross compilation on clang.
Use both variables to detect bitsize and target arguments for userprogs.
Fixes: feb843a469 ("kbuild: add $(CLANG_FLAGS) to KBUILD_CPPFLAGS")
Cc: stable@vger.kernel.org
Signed-off-by: Thomas Weißschuh <thomas.weissschuh@linutronix.de>
Reviewed-by: Nathan Chancellor <nathan@kernel.org>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
When CONFIG_OBJTOOL=y or CONFIG_DEBUG_INFO_BTF=y, parallel builds
show awkward "mkdir -p ..." logs.
$ make -j16
[ snip ]
mkdir -p /home/masahiro/ref/linux/tools/objtool && make O=/home/masahiro/ref/linux subdir=tools/objtool --no-print-directory -C objtool
mkdir -p /home/masahiro/ref/linux/tools/bpf/resolve_btfids && make O=/home/masahiro/ref/linux subdir=tools/bpf/resolve_btfids --no-print-directory -C bpf/resolve_btfids
Defining MAKEFLAGS=<value> on the command line wipes out command line
switches from the resultant MAKEFLAGS definition, even though the command
line switches are active. [1]
MAKEFLAGS puts all single-letter options into the first word, and that
word will be empty if no single-letter options were given. [2]
However, this breaks if MAKEFLAGS=<value> is given on the command line.
The tools/ and tools/% targets set MAKEFLAGS=<value> on the command
line, which breaks the following code in tools/scripts/Makefile.include:
short-opts := $(firstword -$(MAKEFLAGS))
If MAKEFLAGS really needs modification, it should be done through the
environment variable, as follows:
MAKEFLAGS=<value> $(MAKE) ...
That said, I question whether modifying MAKEFLAGS is necessary here.
The only flag we might want to exclude is --no-print-directory, as the
tools build system changes the working directory. However, people might
find the "Entering/Leaving directory" logs annoying.
I simply removed the offending MAKEFLAGS=<value>.
[1]: https://savannah.gnu.org/bugs/?62469
[2]: https://www.gnu.org/software/make/manual/make.html#Testing-Flags
Fixes: ea01fa9f63 ("tools: Connect to the kernel build system")
Fixes: a50e433327 ("perf tools: Honor parallel jobs")
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Tested-by: Daniel Xu <dxu@dxuuu.xyz>
Pull networking updates from Paolo Abeni:
"This is slightly smaller than usual, with the most interesting work
being still around RTNL scope reduction.
Core:
- More core refactoring to reduce the RTNL lock contention, including
preparatory work for the per-network namespace RTNL lock, replacing
RTNL lock with a per device-one to protect NAPI-related net device
data and moving synchronize_net() calls outside such lock.
- Extend drop reasons usage, adding net scheduler, AF_UNIX, bridge
and more specific TCP coverage.
- Reduce network namespace tear-down time by removing per-subsystems
synchronize_net() in tipc and sched.
- Add flow label selector support for fib rules, allowing traffic
redirection based on such header field.
Netfilter:
- Do not remove netdev basechain when last device is gone, allowing
netdev basechains without devices.
- Revisit the flowtable teardown strategy, dealing better with fin,
reset and re-open events.
- Scale-up IP-vs connection dumping by avoiding linear search on each
restart.
Protocols:
- A significant XDP socket refactor, consolidating and optimizing
several helpers into the core
- Better scaling of ICMP rate-limiting, by removing false-sharing in
inet peers handling.
- Introduces netlink notifications for multicast IPv4 and IPv6
address changes.
- Add ipsec support for IP-TFS/AggFrag encapsulation, allowing
aggregation and fragmentation of the inner IP.
- Add sysctl to configure TIME-WAIT reuse delay for TCP sockets, to
avoid local port exhaustion issues when the average connection
lifetime is very short.
- Support updating keys (re-keying) for connections using kernel TLS
(for TLS 1.3 only).
- Support ipv4-mapped ipv6 address clients in smc-r v2.
- Add support for jumbo data packet transmission in RxRPC sockets,
gluing multiple data packets in a single UDP packet.
- Support RxRPC RACK-TLP to manage packet loss and retransmission in
conjunction with the congestion control algorithm.
Driver API:
- Introduce a unified and structured interface for reporting PHY
statistics, exposing consistent data across different H/W via
ethtool.
- Make timestamping selectable, allow the user to select the desired
hwtstamp provider (PHY or MAC) administratively.
- Add support for configuring a header-data-split threshold (HDS)
value via ethtool, to deal with partial or buggy H/W
implementation.
- Consolidate DSA drivers Energy Efficiency Ethernet support.
- Add EEE management to phylink, making use of the phylib
implementation.
- Add phylib support for in-band capabilities negotiation.
- Simplify how phylib-enabled mac drivers expose the supported
interfaces.
Tests and tooling:
- Make the YNL tool package-friendly to make it easier to deploy it
separately from the kernel.
- Increase TCP selftest coverage importing several packetdrill
test-cases.
- Regenerate the ethtool uapi header from the YNL spec, to ease
maintenance and future development.
- Add YNL support for decoding the link types used in net self-tests,
allowing a single build to run both net and drivers/net.
Drivers:
- Ethernet high-speed NICs:
- nVidia/Mellanox (mlx5):
- add cross E-Switch QoS support
- add SW Steering support for ConnectX-8
- implement support for HW-Managed Flow Steering, improving the
rule deletion/insertion rate
- support for multi-host LAG
- Intel (ixgbe, ice, igb):
- ice: add support for devlink health events
- ixgbe: add initial support for E610 chipset variant
- igb: add support for AF_XDP zero-copy
- Meta:
- add support for basic RSS config
- allow changing the number of channels
- add hardware monitoring support
- Broadcom (bnxt):
- implement TCP data split and HDS threshold ethtool support,
enabling Device Memory TCP.
- Marvell Octeon:
- implement egress ipsec offload support for the cn10k family
- Hisilicon (HIBMC):
- implement unicast MAC filtering
- Ethernet NICs embedded and virtual:
- Convert UDP tunnel drivers to NETDEV_PCPU_STAT_DSTATS, avoiding
contented atomic operations for drop counters
- Freescale:
- quicc: phylink conversion
- enetc: support Tx and Rx checksum offload and improve TSO
performances
- MediaTek:
- airoha: introduce support for ETS and HTB Qdisc offload
- Microchip:
- lan78XX USB: preparation work for phylink conversion
- Synopsys (stmmac):
- support DWMAC IP on NXP Automotive SoCs S32G2xx/S32G3xx/S32R45
- refactor EEE support to leverage the new driver API
- optimize DMA and cache access to increase raw RX performances
by 40%
- TI:
- icssg-prueth: add multicast filtering support for VLAN
interface
- netkit:
- add ability to configure head/tailroom
- VXLAN:
- accepts packets with user-defined reserved bit
- Ethernet switches:
- Microchip:
- lan969x: add RGMII support
- lan969x: improve TX and RX performance using the FDMA engine
- nVidia/Mellanox:
- move Tx header handling to PCI driver, to ease XDP support
- Ethernet PHYs:
- Texas Instruments DP83822:
- add support for GPIO2 clock output
- Realtek:
- 8169: add support for RTL8125D rev.b
- rtl822x: add hwmon support for the temperature sensor
- Microchip:
- add support for RDS PTP hardware
- consolidate periodic output signal generation
- CAN:
- several DT-bindings to DT schema conversions
- tcan4x5x:
- add HW standby support
- support nWKRQ voltage selection
- kvaser:
- allowing Bus Error Reporting runtime configuration
- WiFi:
- the on-going Multi-Link Operation (MLO) effort continues,
affecting both the stack and in drivers
- mac80211/cfg80211:
- Emergency Preparedness Communication Services (EPCS) station
mode support
- support for adding and removing station links for MLO
- add support for WiFi 7/EHT mesh over 320 MHz channels
- report Tx power info for each link
- RealTek (rtw88):
- enable USB Rx aggregation and USB 3 to improve performance
- LED support
- RealTek (rtw89):
- refactor power save to support Multi-Link Operations
- add support for RTL8922AE-VS variant
- MediaTek (mt76):
- single wiphy multiband support (preparation for MLO)
- p2p device support
- add TP-Link TXE50UH USB adapter support
- Qualcomm (ath10k):
- support for the QCA6698AQ IP core
- Qualcomm (ath12k):
- enable MLO for QCN9274
- Bluetooth:
- Allow sysfs to trigger hdev reset, to allow recovering devices
not responsive from user-space
- MediaTek: add support for MT7922, MT7925, MT7921e devices
- Realtek: add support for RTL8851BE devices
- Qualcomm: add support for WCN785x devices
- ISO: allow BIG re-sync"
* tag 'net-next-6.14' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next: (1386 commits)
net/rose: prevent integer overflows in rose_setsockopt()
net: phylink: fix regression when binding a PHY
net: ethernet: ti: am65-cpsw: streamline TX queue creation and cleanup
net: ethernet: ti: am65-cpsw: streamline RX queue creation and cleanup
net: ethernet: ti: am65-cpsw: ensure proper channel cleanup in error path
ipv6: Convert inet6_rtm_deladdr() to per-netns RTNL.
ipv6: Convert inet6_rtm_newaddr() to per-netns RTNL.
ipv6: Move lifetime validation to inet6_rtm_newaddr().
ipv6: Set cfg.ifa_flags before device lookup in inet6_rtm_newaddr().
ipv6: Pass dev to inet6_addr_add().
ipv6: Convert inet6_ioctl() to per-netns RTNL.
ipv6: Hold rtnl_net_lock() in addrconf_init() and addrconf_cleanup().
ipv6: Hold rtnl_net_lock() in addrconf_dad_work().
ipv6: Hold rtnl_net_lock() in addrconf_verify_work().
ipv6: Convert net.ipv6.conf.${DEV}.XXX sysctl to per-netns RTNL.
ipv6: Add __in6_dev_get_rtnl_net().
net: stmmac: Drop redundant skb_mark_for_recycle() for SKB frags
net: mii: Fix the Speed display when the network cable is not connected
sysctl net: Remove macro checks for CONFIG_SYSCTL
eth: bnxt: update header sizing defaults
...
Pull rust updates from Miguel Ojeda:
"Toolchain and infrastructure:
- Finish the move to custom FFI integer types started in the previous
cycle and finally map 'long' to 'isize' and 'char' to 'u8'. Do a
few cleanups on top thanks to that.
- Start to use 'derive(CoercePointee)' on Rust >= 1.84.0.
This is a major milestone on the path to build the kernel using
only stable Rust features. In particular, previously we were using
the unstable features 'coerce_unsized', 'dispatch_from_dyn' and
'unsize', and now we will use the new 'derive_coerce_pointee' one,
which is on track to stabilization. This new feature is a macro
that essentially expands into code that internally uses the
unstable features that we were using before, without having to
expose those.
With it, stable Rust users, including the kernel, will be able to
build custom smart pointers that work with trait objects, e.g.:
fn f(p: &Arc<dyn Display>) {
pr_info!("{p}\n");
}
let a: Arc<dyn Display> = Arc::new(42i32, GFP_KERNEL)?;
let b: Arc<dyn Display> = Arc::new("hello there", GFP_KERNEL)?;
f(&a); // Prints "42".
f(&b); // Prints "hello there".
Together with the 'arbitrary_self_types' feature that we started
using in the previous cycle, using our custom smart pointers like
'Arc' will eventually only rely in stable Rust.
- Introduce 'PROCMACROLDFLAGS' environment variable to allow to link
Rust proc macros using different flags than those used for linking
Rust host programs (e.g. when 'rustc' uses a different C library
than the host programs' one), which Android needs.
- Help kernel builds under macOS with Rust enabled by accomodating
other naming conventions for dynamic libraries (i.e. '.so' vs.
'.dylib') which are used for Rust procedural macros. The actual
support for macOS (i.e. the rest of the pieces needed) is provided
out-of-tree by others, following the policy used for other parts of
the kernel by Kbuild.
- Run Clippy for 'rusttest' code too and clean the bits it spotted.
- Provide Clippy with the minimum supported Rust version to improve
the suggestions it gives.
- Document 'bindgen' 0.71.0 regression.
'kernel' crate:
- 'build_error!': move users of the hidden function to the documented
macro, prevent such uses in the future by moving the function
elsewhere and add the macro to the prelude.
- 'types' module: add improved version of 'ForeignOwnable::borrow_mut'
(which was removed in the past since it was problematic); change
'ForeignOwnable' pointer type to '*mut'.
- 'alloc' module: implement 'Display' for 'Box' and align the 'Debug'
implementation to it; add example (doctest) for 'ArrayLayout::new()'
- 'sync' module: document 'PhantomData' in 'Arc'; use
'NonNull::new_unchecked' in 'ForeignOwnable for Arc' impl.
- 'uaccess' module: accept 'Vec's with different allocators in
'UserSliceReader::read_all'.
- 'workqueue' module: enable run-testing a couple more doctests.
- 'error' module: simplify 'from_errno()'.
- 'block' module: fix formatting in code documentation (a lint to catch
these is being implemented).
- Avoid 'unwrap()'s in doctests, which also improves the examples by
showing how kernel code is supposed to be written.
- Avoid 'as' casts with 'cast{,_mut}' calls which are a bit safer.
And a few other cleanups"
* tag 'rust-6.14' of git://git.kernel.org/pub/scm/linux/kernel/git/ojeda/linux: (32 commits)
kbuild: rust: add PROCMACROLDFLAGS
rust: uaccess: generalize userSliceReader to support any Vec
rust: kernel: add improved version of `ForeignOwnable::borrow_mut`
rust: kernel: reorder `ForeignOwnable` items
rust: kernel: change `ForeignOwnable` pointer to mut
rust: arc: split unsafe block, add missing comment
rust: types: avoid `as` casts
rust: arc: use `NonNull::new_unchecked`
rust: use derive(CoercePointee) on rustc >= 1.84.0
rust: alloc: add doctest for `ArrayLayout::new()`
rust: init: update `stack_try_pin_init` examples
rust: error: import `kernel`'s `LayoutError` instead of `core`'s
rust: str: replace unwraps with question mark operators
rust: page: remove unnecessary helper function from doctest
rust: rbtree: remove unwrap in asserts
rust: init: replace unwraps with question mark operators
rust: use host dylib naming convention to support macOS
rust: add `build_error!` to the prelude
rust: kernel: move `build_error` hidden function to prevent mistakes
rust: use the `build_error!` macro, not the hidden function
...
These are flags to be passed when linking proc macros for the Rust
toolchain. If unset, it defaults to $(KBUILD_HOSTLDFLAGS).
This is needed because the list of flags to link hostprogs is not
necessarily the same as the list of flags used to link libmacros.so.
When we build proc macros, we need the latter, not the former (e.g. when
using a Rust compiler binary linked to a different C library than host
programs).
To distinguish between the two, introduce this new variable to stand
out from KBUILD_HOSTLDFLAGS used to link other host progs.
Signed-off-by: HONG Yifan <elsk@google.com>
Link: https://lore.kernel.org/r/20241017210430.2401398-2-elsk@google.com
[ v3:
- `export`ed the variable. Otherwise it would not be visible in
`rust/Makefile`.
- Removed "additional" from the documentation and commit message,
since this actually replaces the other flags, unlike other cases.
- Added example of use case to documentation and commit message.
Thanks Alice for the details on what Google needs!
- Instead of `HOSTLDFLAGS`, used `KBUILD_HOSTLDFLAGS` as the fallback
to preserve the previous behavior as much as possible, as discussed
with Alice/Yifan. Thus moved the variable down too (currently we
do not modify `KBUILD_HOSTLDFLAGS` elsewhere) and avoided
mentioning `HOSTLDFLAGS` directly in the documentation.
- Fixed documentation header formatting.
- Reworded slightly.
- Miguel ]
Tested-by: Alice Ryhl <aliceryhl@google.com>
Reviewed-by: Alice Ryhl <aliceryhl@google.com>
Reviewed-by: HONG Yifan <elsk@google.com>
Acked-by: Masahiro Yamada <masahiroy@kernel.org>
Link: https://lore.kernel.org/r/20241112184455.855133-1-ojeda@kernel.org
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
Because the `macros` crate exposes procedural macros, it must be
compiled as a dynamic library (so it can be loaded by the compiler at
compile-time).
Before this change the resulting artifact was always named
`libmacros.so`, which works on hosts where this matches the naming
convention for dynamic libraries. However the proper name on macOS would
be `libmacros.dylib`.
This turns out to matter even when the dependency is passed with a path
(`--extern macros=path/to/libmacros.so` rather than `--extern macros`)
because rustc uses the file name to infer the type of the library (see
link). This is because there's no way to specify both the path to and
the type of the external library via CLI flags. The compiler could
speculatively parse the file to determine its type, but it does not do
so today.
This means that libraries that match neither rustc's naming convention
for static libraries nor the platform's naming convention for dynamic
libraries are *rejected*.
The only solution I've found is to follow the host platform's naming
convention. This patch does that by querying the compiler to determine
the appropriate name for the artifact. This allows the kernel to build
with CONFIG_RUST=y on macOS.
Link: https://github.com/rust-lang/rust/blob/d829780/compiler/rustc_metadata/src/locator.rs#L728-L752
Tested-by: Daniel Gomez <da.gomez@samsung.com>
Co-developed-by: Fiona Behrens <me@kloenk.dev>
Signed-off-by: Fiona Behrens <me@kloenk.dev>
Signed-off-by: Tamir Duberstein <tamird@gmail.com>
Tested-by: Andreas Hindborg <a.hindborg@kernel.org>
Link: https://lore.kernel.org/r/20241216-b4-dylib-host-macos-v7-1-cfc507681447@gmail.com
[ Added `MAKEFLAGS=`s to avoid jobserver warnings. Removed space.
Reworded title. - Miguel ]
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
This is new API which caters to the following requirements:
- Pack or unpack a large number of fields to/from a buffer with a small
code footprint. The current alternative is to open-code a large number
of calls to pack() and unpack(), or to use packing() to reduce that
number to half. But packing() is not const-correct.
- Use unpacked numbers stored in variables smaller than u64. This
reduces the rodata footprint of the stored field arrays.
- Perform error checking at compile time, rather than runtime, and return
void from the API functions. Because the C preprocessor can't generate
variable length code (loops), this is a bit tricky to do with macros.
To handle this, implement macros which sanity check the packed field
definitions based on their size. Finally, a single macro with a chain of
__builtin_choose_expr() is used to select the appropriate macros. We
enforce the use of ascending or descending order to avoid O(N^2) scaling
when checking for overlap. Note that the macros are written with care to
ensure that the compilers can correctly evaluate the resulting code at
compile time. In particular, care was taken with avoiding too many nested
statement expressions. Nested statement expressions trip up some
compilers, especially when passing down variables created in previous
statement expressions.
There are two key design choices intended to keep the overall macro code
size small. First, the definition of each CHECK_PACKED_FIELDS_N macro is
implemented recursively, by calling the N-1 macro. This avoids needing
the code to repeat multiple times.
Second, the CHECK_PACKED_FIELD macro enforces that the fields in the
array are sorted in order. This allows checking for overlap only with
neighboring fields, rather than the general overlap case where each field
would need to be checked against other fields.
The overlap checks use the first two fields to determine the order of the
remaining fields, thus allowing either ascending or descending order.
This enables drivers the flexibility to keep the fields ordered in which
ever order most naturally fits their hardware design and its associated
documentation.
The CHECK_PACKED_FIELDS macro is directly called from within pack_fields
and unpack_fields, ensuring that all drivers using the API receive the
benefits of the compile-time checks. Users do not need to directly call
any of the macros directly.
The CHECK_PACKED_FIELDS and its helper macros CHECK_PACKED_FIELDS_(0..50)
are generated using a simple C program in scripts/gen_packed_field_checks.c
This program can be compiled on demand and executed to generate the
macro code in include/linux/packing.h. This will aid in the event that a
driver needs more than 50 fields. The generator can be updated with a new
size, and used to update the packing.h header file. In practice, the ice
driver will need to support 27 fields, and the sja1105 driver will need
to support 0 fields. This on-demand generation avoids the need to modify
Kbuild. We do not anticipate the maximum number of fields to grow very
often.
- Reduced rodata footprint for the storage of the packed field arrays.
To that end, we have struct packed_field_u8 and packed_field_u16, which
define the fields with the associated type. More can be added as
needed (unlikely for now). On these types, the same generic pack_fields()
and unpack_fields() API can be used, thanks to the new C11 _Generic()
selection feature, which can call pack_fields_u8() or pack_fields_16(),
depending on the type of the "fields" array - a simplistic form of
polymorphism. It is evaluated at compile time which function will actually
be called.
Over time, packing() is expected to be completely replaced either with
pack() or with pack_fields().
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Co-developed-by: Jacob Keller <jacob.e.keller@intel.com>
Signed-off-by: Jacob Keller <jacob.e.keller@intel.com>
Reviewed-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Link: https://patch.msgid.link/20241210-packing-pack-fields-and-ice-implementation-v10-3-ee56a47479ac@intel.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Pull Kbuild updates from Masahiro Yamada:
- Add generic support for built-in boot DTB files
- Enable TAB cycling for dialog buttons in nconfig
- Fix issues in streamline_config.pl
- Refactor Kconfig
- Add support for Clang's AutoFDO (Automatic Feedback-Directed
Optimization)
- Add support for Clang's Propeller, a profile-guided optimization.
- Change the working directory to the external module directory for M=
builds
- Support building external modules in a separate output directory
- Enable objtool for *.mod.o and additional kernel objects
- Use lz4 instead of deprecated lz4c
- Work around a performance issue with "git describe"
- Refactor modpost
* tag 'kbuild-v6.13' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild: (85 commits)
kbuild: rename .tmp_vmlinux.kallsyms0.syms to .tmp_vmlinux0.syms
gitignore: Don't ignore 'tags' directory
kbuild: add dependency from vmlinux to resolve_btfids
modpost: replace tdb_hash() with hash_str()
kbuild: deb-pkg: add python3:native to build dependency
genksyms: reduce indentation in export_symbol()
modpost: improve error messages in device_id_check()
modpost: rename alias symbol for MODULE_DEVICE_TABLE()
modpost: rename variables in handle_moddevtable()
modpost: move strstarts() to modpost.h
modpost: convert do_usb_table() to a generic handler
modpost: convert do_of_table() to a generic handler
modpost: convert do_pnp_device_entry() to a generic handler
modpost: convert do_pnp_card_entries() to a generic handler
modpost: call module_alias_printf() from all do_*_entry() functions
modpost: pass (struct module *) to do_*_entry() functions
modpost: remove DEF_FIELD_ADDR_VAR() macro
modpost: deduplicate MODULE_ALIAS() for all drivers
modpost: introduce module_alias_printf() helper
modpost: remove unnecessary check in do_acpi_entry()
...
Replace lz4c with lz4 for kernel image compression.
Although lz4 and lz4c are functionally similar, lz4c has been deprecated
upstream since 2018. Since as early as Ubuntu 16.04 and Fedora 25, lz4
and lz4c have been packaged together, making it safe to update the
requirement from lz4c to lz4.
Consequently, some distributions and build systems, such as OpenEmbedded,
have fully transitioned to using lz4. OpenEmbedded core adopted this
change in commit fe167e082cbd ("bitbake.conf: require lz4 instead of
lz4c"), causing compatibility issues when building the mainline kernel
in the latest OpenEmbedded environment, as seen in the errors below.
This change also updates the LZ4 compression commands to make it backward
compatible by replacing stdin and stdout with the '-' option, due to some
unclear reason, the stdout keyword does not work for lz4 and '-' works for
both. In addition, this modifies the legacy '-c1' with '-9' which is also
compatible with both. This fixes the mainline kernel build failures with
the latest master OpenEmbedded builds associated with the mentioned
compatibility issues.
LZ4 arch/arm/boot/compressed/piggy_data
/bin/sh: 1: lz4c: not found
...
...
ERROR: oe_runmake failed
Link: https://github.com/lz4/lz4/pull/553
Suggested-by: Francesco Dolcini <francesco.dolcini@toradex.com>
Signed-off-by: Parth Pancholi <parth.pancholi@toradex.com>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
