In the upstream commit 214c0eea43
("kbuild: add $(objtree)/ prefix to some in-kernel build artifacts")
artifacts required for building out-of-tree kernel modules had
$(objtree) prepended to them to prepare for building in other
directories.
When building external modules for powerpc,
arch/powerpc/lib/crtsavres.o is required for certain
configurations. This artifact is missing the prepended $(objtree).
Fixes: 13b25489b6 ("kbuild: change working directory to external module directory with M=")
Acked-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Nicolas Schier <n.schier@avm.de>
Tested-by: Nicolas Schier <n.schier@avm.de>
Signed-off-by: Kienan Stewart <kstewart@efficios.com>
Signed-off-by: Madhavan Srinivasan <maddy@linux.ibm.com>
Link: https://patch.msgid.link/20250218-buildfix-extmod-powerpc-v2-1-1e78fcf12b56@efficios.com
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()
...
$(objtree) refers to the top of the output directory of kernel builds.
This commit adds the explicit $(objtree)/ prefix to build artifacts
needed for building external modules.
This change has no immediate impact, as the top-level Makefile
currently defines:
objtree := .
This commit prepares for supporting the building of external modules
in a different directory.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Nicolas Schier <nicolas@fjasle.eu>
Implement support for DYNAMIC_FTRACE_WITH_CALL_OPS similar to the
arm64 implementation.
This works by patching-in a pointer to an associated ftrace_ops
structure before each traceable function. If multiple ftrace_ops are
associated with a call site, then a special ftrace_list_ops is used to
enable iterating over all the registered ftrace_ops. If no ftrace_ops
are associated with a call site, then a special ftrace_nop_ops structure
is used to render the ftrace call as a no-op. ftrace trampoline can then
read the associated ftrace_ops for a call site by loading from an offset
from the LR, and branch directly to the associated function.
The primary advantage with this approach is that we don't have to
iterate over all the registered ftrace_ops for call sites that have a
single ftrace_ops registered. This is the equivalent of implementing
support for dynamic ftrace trampolines, which set up a special ftrace
trampoline for each registered ftrace_ops and have individual call sites
branch into those directly.
A secondary advantage is that this gives us a way to add support for
direct ftrace callers without having to resort to using stubs. The
address of the direct call trampoline can be loaded from the ftrace_ops
structure.
To support this, we reserve a nop before each function on 32-bit
powerpc. For 64-bit powerpc, two nops are reserved before each
out-of-line stub. During ftrace activation, we update this location with
the associated ftrace_ops pointer. Then, on ftrace entry, we load from
this location and call into ftrace_ops->func().
For 64-bit powerpc, we ensure that the out-of-line stub area is
doubleword aligned so that ftrace_ops address can be updated atomically.
Signed-off-by: Naveen N Rao <naveen@kernel.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://patch.msgid.link/20241030070850.1361304-15-hbathini@linux.ibm.com
Function profile sequence on powerpc includes two instructions at the
beginning of each function:
mflr r0
bl ftrace_caller
The call to ftrace_caller() gets nop'ed out during kernel boot and is
patched in when ftrace is enabled.
Given the sequence, we cannot return from ftrace_caller with 'blr' as we
need to keep LR and r0 intact. This results in link stack (return
address predictor) imbalance when ftrace is enabled. To address that, we
would like to use a three instruction sequence:
mflr r0
bl ftrace_caller
mtlr r0
Further more, to support DYNAMIC_FTRACE_WITH_CALL_OPS, we need to
reserve two instruction slots before the function. This results in a
total of five instruction slots to be reserved for ftrace use on each
function that is traced.
Move the function profile sequence out-of-line to minimize its impact.
To do this, we reserve a single nop at function entry using
-fpatchable-function-entry=1 and add a pass on vmlinux.o to determine
the total number of functions that can be traced. This is then used to
generate a .S file reserving the appropriate amount of space for use as
ftrace stubs, which is built and linked into vmlinux.
On bootup, the stub space is split into separate stubs per function and
populated with the proper instruction sequence. A pointer to the
associated stub is maintained in dyn_arch_ftrace.
For modules, space for ftrace stubs is reserved from the generic module
stub space.
This is restricted to and enabled by default only on 64-bit powerpc,
though there are some changes to accommodate 32-bit powerpc. This is
done so that 32-bit powerpc could choose to opt into this based on
further tests and benchmarks.
As an example, after this patch, kernel functions will have a single nop
at function entry:
<kernel_clone>:
addis r2,r12,467
addi r2,r2,-16028
nop
mfocrf r11,8
...
When ftrace is enabled, the nop is converted to an unconditional branch
to the stub associated with that function:
<kernel_clone>:
addis r2,r12,467
addi r2,r2,-16028
b ftrace_ool_stub_text_end+0x11b28
mfocrf r11,8
...
The associated stub:
<ftrace_ool_stub_text_end+0x11b28>:
mflr r0
bl ftrace_caller
mtlr r0
b kernel_clone+0xc
...
This change showed an improvement of ~10% in null_syscall benchmark on a
Power 10 system with ftrace enabled.
Signed-off-by: Naveen N Rao <naveen@kernel.org>
Signed-off-by: Hari Bathini <hbathini@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://patch.msgid.link/20241030070850.1361304-13-hbathini@linux.ibm.com
After fixing the HAVE_STACKPROTECTER checks for clang's in-progress
per-task stack protector support [1], the build fails during prepare0
because '-mstack-protector-guard-offset' has not been added to
KBUILD_CFLAGS yet but the other '-mstack-protector-guard' flags have.
clang: error: '-mstack-protector-guard=tls' is used without '-mstack-protector-guard-offset', and there is no default
clang: error: '-mstack-protector-guard=tls' is used without '-mstack-protector-guard-offset', and there is no default
make[4]: *** [scripts/Makefile.build:229: scripts/mod/empty.o] Error 1
make[4]: *** [scripts/Makefile.build:102: scripts/mod/devicetable-offsets.s] Error 1
Mirror other architectures and add all '-mstack-protector-guard' flags
to KBUILD_CFLAGS atomically during stack_protector_prepare, which
resolves the issue and allows clang's implementation to fully work with
the kernel.
Cc: stable@vger.kernel.org # 6.1+
Link: https://github.com/llvm/llvm-project/pull/110928 [1]
Reviewed-by: Keith Packard <keithp@keithp.com>
Tested-by: Keith Packard <keithp@keithp.com>
Signed-off-by: Nathan Chancellor <nathan@kernel.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://patch.msgid.link/20241009-powerpc-fix-stackprotector-test-clang-v2-2-12fb86b31857@kernel.org
Pull powerpc updates from Michael Ellerman:
- Add AT_HWCAP3 and AT_HWCAP4 aux vector entries for future use
by glibc
- Add support for recognising the Power11 architected and raw PVRs
- Add support for nr_cpus=n on the command line where the
boot CPU is >= n
- Add ppcxx_allmodconfig targets for all 32-bit sub-arches
- Other small features, cleanups and fixes
Thanks to Akanksha J N, Brian King, Christophe Leroy, Dawei Li, Geoff
Levand, Greg Kroah-Hartman, Jan-Benedict Glaw, Kajol Jain, Kunwu Chan,
Li zeming, Madhavan Srinivasan, Masahiro Yamada, Nathan Chancellor,
Nicholas Piggin, Peter Bergner, Qiheng Lin, Randy Dunlap, Ricardo B.
Marliere, Rob Herring, Sathvika Vasireddy, Shrikanth Hegde, Uwe
Kleine-König, Vaibhav Jain, and Wen Xiong.
* tag 'powerpc-6.9-1' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux: (71 commits)
powerpc/macio: Make remove callback of macio driver void returned
powerpc/83xx: Fix build failure with FPU=n
powerpc/64s: Fix get_hugepd_cache_index() build failure
powerpc/4xx: Fix warp_gpio_leds build failure
powerpc/amigaone: Make several functions static
powerpc/embedded6xx: Fix no previous prototype for avr_uart_send() etc.
macintosh/adb: make adb_dev_class constant
powerpc: xor_vmx: Add '-mhard-float' to CFLAGS
powerpc/fsl: Fix mfpmr() asm constraint error
powerpc: Remove cpu-as-y completely
powerpc/fsl: Modernise mt/mfpmr
powerpc/fsl: Fix mfpmr build errors with newer binutils
powerpc/64s: Use .machine power4 around dcbt
powerpc/64s: Move dcbt/dcbtst sequence into a macro
powerpc/mm: Code cleanup for __hash_page_thp
powerpc/hv-gpci: Fix the H_GET_PERF_COUNTER_INFO hcall return value checks
powerpc/irq: Allow softirq to hardirq stack transition
powerpc: Stop using of_root
powerpc/machdep: Define 'compatibles' property in ppc_md and use it
of: Reimplement of_machine_is_compatible() using of_machine_compatible_match()
...
cpu-as-y is there to force assembler building options. But there is no
need for that. GCC is passed the necessary options and it automatically
pass the appropriate option to GAS.
GCC is given -maltivec when relevant, so no need for -Wa,-maltivec
either.
And -Wa,-many is wrong as it will hide innapropriate instructions.
Better to detect them and handle them on a case by case basis.
The setting of -Wa,-many was added by commit 960e300298
("powerpc/Makefile: Fix PPC_BOOK3S_64 ASFLAGS") in order to fix an issue
with clang and the passed -Wa,-mpower4 option. But we have now removed
it expecting the compiler to automatically pass the proper options and
instructions based on -mcpu=power4.
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Acked-by: Segher Boessenkool <segher@kernel.crashing.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/20240229122521.762431-5-mpe@ellerman.id.au
32-bit powerpc kernels can be built for one of 5 sub-arches, see
Kconfig.cputype:
PPC_BOOK3S_32: "512x/52xx/6xx/7xx/74xx/82xx/83xx/86xx"
PPC_85xx: "Freescale 85xx"
PPC_8xx: "Freescale 8xx"
40x: "AMCC 40x"
44x: "AMCC 44x, 46x or 47x"
By default none of these are built for a plain allmodconfig build,
because it selects PPC64 which builds a 64-bit kernel.
There is already a ppc32_allmodconfig, which enables PPC_BOOK3S_32.
Add similar targets for the other 32-bit sub-arches to increase build
coverage:
ppc40x_allmodconfig
ppc44x_allmodconfig
ppc8xx_allmodconfig
ppc85xx_allmodconfig
Acked-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/20240229114108.743810-1-mpe@ellerman.id.au
If no cross compiler is specified, try to auto detect one.
Look for various combinations, matching:
powerpc(64(le)?)?(-unknown)?-linux(-gnu)?-
There are more possibilities, but the above is known to find a compiler
on Fedora and Ubuntu (which use linux-gnu-), and also detects the
kernel.org cross compilers (which use linux-).
This allows cross compiling with simply:
# Ubuntu
$ sudo apt install gcc-powerpc-linux-gnu
# Fedora
$ sudo dnf install gcc-powerpc64-linux-gnu
$ make ARCH=powerpc defconfig
$ make ARCH=powerpc -j 4
Inspired by arch/parisc/Makefile.
Acked-by: Segher Boessenkool <segher@kernel.crashing.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/20231206115548.1466874-4-mpe@ellerman.id.au
If the kernel is being cross compiled, there is no information from
uname on which defconfig is most appropriate, so the Makefile defaults
to ppc64.
However these days almost all distros that support powerpc are little
endian, so it's more likely that defaulting to ppc64le_defconfig will
produce something useful for a user.
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/20231206115548.1466874-3-mpe@ellerman.id.au
Currently the -mtune options are set in the Makefile, depending on what
the compiler supports.
One downside of doing it that way is that the chosen -mtune option is
not recorded in the .config.
Another downside is that if there's ever a need to do more complicated
logic to calculate the correct option, that gets messy in the Makefile.
So move the determination of which -mtune option to use into Kconfig
logic.
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/20230329234308.2215833-1-mpe@ellerman.id.au
GCC v13.1 updated support for -fpatchable-function-entry on ppc64le to
emit nops after the local entry point, rather than before it. This
allows us to use this in the kernel for ftrace purposes. A new script is
added under arch/powerpc/tools/ to help detect if nops are emitted after
the function local entry point, or before the global entry point.
With -fpatchable-function-entry, we no longer have the profiling
instructions generated at function entry, so we only need to validate
the presence of two nops at the ftrace location in ftrace_init_nop(). We
patch the preceding instruction with 'mflr r0' to match the
-mprofile-kernel ABI for subsequent ftrace use.
This changes the profiling instructions used on ppc32. The default -pg
option emits an additional 'stw' instruction after 'mflr r0' and before
the branch to _mcount 'bl _mcount'. This is very similar to the original
-mprofile-kernel implementation on ppc64le, where an additional 'std'
instruction was used to save LR to its save location in the caller's
stackframe. Subsequently, this additional store was removed in later
compiler versions for performance reasons. The same reasons apply for
ppc32 so we only patch in a 'mflr r0'.
Signed-off-by: Naveen N Rao <naveen@kernel.org>
Reviewed-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/68586d22981a2c3bb45f27a2b621173d10a7d092.1687166935.git.naveen@kernel.org
binutils v2.37 drops unused section symbols, which prevents recordmcount
from capturing mcount locations in sections that have no non-weak
symbols. This results in a build failure with a message such as:
Cannot find symbol for section 12: .text.perf_callchain_kernel.
kernel/events/callchain.o: failed
The change to binutils was reverted for v2.38, so this behavior is
specific to binutils v2.37:
https://sourceware.org/git/?p=binutils-gdb.git;a=commit;h=c09c8b42021180eee9495bd50d8b35e683d3901b
Objtool is able to cope with such sections, so this issue is specific to
recordmcount.
Fail the build and print a warning if binutils v2.37 is detected and if
we are using recordmcount.
Cc: stable@vger.kernel.org
Suggested-by: Joel Stanley <joel@jms.id.au>
Signed-off-by: Naveen N Rao <naveen@kernel.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/20230530061436.56925-1-naveen@kernel.org
x86 removed -pipe in commit 437e88ab8f ("x86/build: Remove -pipe from
KBUILD_CFLAGS") and the newer arm64 and riscv seem to have never used it,
so that seems to be the way the world's going.
Compile performance building defconfig on a POWER10 PowerNV system
was in the noise after 10 builds each. No point in adding options unless
they help something, so remove it.
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/20230606064830.184083-1-npiggin@gmail.com
Rather than trying to keep multiple configs up to date, make
pseries_defconfig an alias for ppc64le_guest_defconfig.
NOTE, pseries_defconfig was a big endian config, but this commit
switches it to little endian.
Almost all distros are ppc64le these days, so little endian is much more
likely to be what a user wants when they build for "pseries".
For an actual big endian guest, use ppc64_guest_defconfig.
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/20230414132415.821564-32-mpe@ellerman.id.au
