Changes in Makefile

214c0eea - kbuild: add $(objtree)/ prefix to some in-kernel build artifacts

Sun, 10 Nov 2024 01:34:30 +0000

kbuild: add $(objtree)/ prefix to some in-kernel build artifacts$(objtree) refers to the top of the output directory of kernel builds.This commit adds the explicit $(objtree)/ prefix to build artifactsneeded for building external modules.This change has no immediate impact, as the top-level Makefilecurrently defines: objtree := .This commit prepares for supporting the building of external modulesin a different directory.Signed-off-by: Masahiro Yamada Reviewed-by: Nicolas Schier List of files: /linux-6.15/arch/powerpc/Makefile

a5371018 - powerpc/Makefile: Allow overriding CPP

Thu, 07 Nov 2024 11:26:46 +0000

powerpc/Makefile: Allow overriding CPPUnlike all other arches, powerpc doesn't allow the user to override CPP,because it sets it unconditionally in the arch Makefile. This can leadto strange build failures.Instead add the required flags to KBUILD_CPPFLAGS, which are passedto CPP, CC and AS invocations by the generic Makefile logic.Reported-by: Arnd Bergmann Tested-by: Nathan Chancellor Reviewed-by: Nathan Chancellor Closes: https://lore.kernel.org/all/20240607061629.530301-1-arnd@kernel.orgSigned-off-by: Arnd Bergmann [mpe: Rebase, write change log, add Arnd's SoB as communicated privately]Signed-off-by: Michael Ellerman Link: https://patch.msgid.link/20241107112646.32401-1-mpe@ellerman.id.au List of files: /linux-6.15/arch/powerpc/Makefile

e717754f - powerpc/ftrace: Add support for DYNAMIC_FTRACE_WITH_CALL_OPS

Wed, 30 Oct 2024 07:08:47 +0000

powerpc/ftrace: Add support for DYNAMIC_FTRACE_WITH_CALL_OPSImplement support for DYNAMIC_FTRACE_WITH_CALL_OPS similar to thearm64 implementation.This works by patching-in a pointer to an associated ftrace_opsstructure before each traceable function. If multiple ftrace_ops areassociated with a call site, then a special ftrace_list_ops is used toenable iterating over all the registered ftrace_ops. If no ftrace_opsare associated with a call site, then a special ftrace_nop_ops structureis used to render the ftrace call as a no-op. ftrace trampoline can thenread the associated ftrace_ops for a call site by loading from an offsetfrom the LR, and branch directly to the associated function.The primary advantage with this approach is that we don't have toiterate over all the registered ftrace_ops for call sites that have asingle ftrace_ops registered. This is the equivalent of implementingsupport for dynamic ftrace trampolines, which set up a special ftracetrampoline for each registered ftrace_ops and have individual call sitesbranch into those directly.A secondary advantage is that this gives us a way to add support fordirect ftrace callers without having to resort to using stubs. Theaddress of the direct call trampoline can be loaded from the ftrace_opsstructure.To support this, we reserve a nop before each function on 32-bitpowerpc. For 64-bit powerpc, two nops are reserved before eachout-of-line stub. During ftrace activation, we update this location withthe associated ftrace_ops pointer. Then, on ftrace entry, we load fromthis location and call into ftrace_ops->func().For 64-bit powerpc, we ensure that the out-of-line stub area isdoubleword aligned so that ftrace_ops address can be updated atomically.Signed-off-by: Naveen N Rao Signed-off-by: Michael Ellerman Link: https://patch.msgid.link/20241030070850.1361304-15-hbathini@linux.ibm.com List of files: /linux-6.15/arch/powerpc/Makefile

eec37961 - powerpc64/ftrace: Move ftrace sequence out of line

Wed, 30 Oct 2024 07:08:45 +0000

powerpc64/ftrace: Move ftrace sequence out of lineFunction profile sequence on powerpc includes two instructions at thebeginning of each function: mflr r0 bl ftrace_callerThe call to ftrace_caller() gets nop'ed out during kernel boot and ispatched in when ftrace is enabled.Given the sequence, we cannot return from ftrace_caller with 'blr' as weneed to keep LR and r0 intact. This results in link stack (returnaddress predictor) imbalance when ftrace is enabled. To address that, wewould like to use a three instruction sequence: mflr r0 bl ftrace_caller mtlr r0Further more, to support DYNAMIC_FTRACE_WITH_CALL_OPS, we need toreserve two instruction slots before the function. This results in atotal of five instruction slots to be reserved for ftrace use on eachfunction 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 determinethe total number of functions that can be traced. This is then used togenerate a .S file reserving the appropriate amount of space for use asftrace stubs, which is built and linked into vmlinux.On bootup, the stub space is split into separate stubs per function andpopulated with the proper instruction sequence. A pointer to theassociated stub is maintained in dyn_arch_ftrace.For modules, space for ftrace stubs is reserved from the generic modulestub 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 isdone so that 32-bit powerpc could choose to opt into this based onfurther tests and benchmarks.As an example, after this patch, kernel functions will have a single nopat function entry:: addis r2,r12,467 addi r2,r2,-16028 nop mfocrf r11,8 ...When ftrace is enabled, the nop is converted to an unconditional branchto the stub associated with that function:: addis r2,r12,467 addi r2,r2,-16028 b ftrace_ool_stub_text_end+0x11b28 mfocrf r11,8 ...The associated stub:: mflr r0 bl ftrace_caller mtlr r0 b kernel_clone+0xc ...This change showed an improvement of ~10% in null_syscall benchmark on aPower 10 system with ftrace enabled.Signed-off-by: Naveen N Rao Signed-off-by: Hari Bathini Signed-off-by: Michael Ellerman Link: https://patch.msgid.link/20241030070850.1361304-13-hbathini@linux.ibm.com List of files: /linux-6.15/arch/powerpc/Makefile

c7182a0b - powerpc/boot: Remove bogus reference to lilo

Wed, 09 Oct 2024 05:38:06 +0000

powerpc/boot: Remove bogus reference to liloThe help text refers to lilo, but the install script does not run liloand never has. The reference to lilo seems to have come originally fromarch/ppc/Makefile, but it was not true there either.Remove it.Reported-by: Thorsten Leemhuis Link: https://fosstodon.org/@kernellogger/113032940928131612Signed-off-by: Michael Ellerman Link: https://patch.msgid.link/20241009053806.135807-1-mpe@ellerman.id.au List of files: /linux-6.15/arch/powerpc/Makefile

bee08a9e - powerpc: Adjust adding stack protector flags to KBUILD_CLAGS for clang

Wed, 09 Oct 2024 19:26:09 +0000

powerpc: Adjust adding stack protector flags to KBUILD_CLAGS for clangAfter fixing the HAVE_STACKPROTECTER checks for clang's in-progressper-task stack protector support [1], the build fails during prepare0because '-mstack-protector-guard-offset' has not been added toKBUILD_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 1Mirror other architectures and add all '-mstack-protector-guard' flagsto KBUILD_CFLAGS atomically during stack_protector_prepare, whichresolves the issue and allows clang's implementation to fully work withthe kernel.Cc: stable@vger.kernel.org # 6.1+Link: https://github.com/llvm/llvm-project/pull/110928 [1]Reviewed-by: Keith Packard Tested-by: Keith Packard Signed-off-by: Nathan Chancellor Signed-off-by: Michael Ellerman Link: https://patch.msgid.link/20241009-powerpc-fix-stackprotector-test-clang-v2-2-12fb86b31857@kernel.org List of files: /linux-6.15/arch/powerpc/Makefile

e939da89 - powerpc: Remove 40x from Kconfig and defconfig

Fri, 28 Jun 2024 12:11:57 +0000

powerpc: Remove 40x from Kconfig and defconfigRemove 40x from Kconfig, making the code unreachable.Signed-off-by: Michael Ellerman Link: https://msgid.link/20240628121201.130802-3-mpe@ellerman.id.au List of files: /linux-6.15/arch/powerpc/Makefile

01db473e - powerpc: implement ARCH_HAS_KERNEL_FPU_SUPPORT

Fri, 29 Mar 2024 07:18:23 +0000

powerpc: implement ARCH_HAS_KERNEL_FPU_SUPPORTPowerPC provides an equivalent to the common kernel-mode FPU API, but in adifferent header and using different function names. The PowerPC API alsorequires a non-preemptible context. Add a wrapper header, and export theCFLAGS adjustments.Link: https://lkml.kernel.org/r/20240329072441.591471-9-samuel.holland@sifive.comSigned-off-by: Samuel Holland Acked-by: Michael Ellerman (powerpc)Reviewed-by: Christoph Hellwig Acked-by: Christian König Cc: Alex Deucher Cc: Borislav Petkov (AMD) Cc: Catalin Marinas Cc: Dave Hansen Cc: Huacai Chen Cc: Ingo Molnar Cc: Jonathan Corbet Cc: Masahiro Yamada Cc: Nathan Chancellor Cc: Nicolas Schier Cc: Palmer Dabbelt Cc: Russell King Cc: Thomas Gleixner Cc: WANG Xuerui Cc: Will Deacon Signed-off-by: Andrew Morton List of files: /linux-6.15/arch/powerpc/Makefile

c330b50d - powerpc/Makefile: Remove bits related to the previous use of -mcmodel=large

Wed, 10 Jan 2024 14:12:37 +0000

powerpc/Makefile: Remove bits related to the previous use of -mcmodel=largeAll supported compilers today (gcc v5.1+ and clang v11+) have support for-mcmodel=medium. As such, NO_MINIMAL_TOC is no longer being set. RemoveNO_MINIMAL_TOC as well as the fallback to -mminimal-toc.Reviewed-by: Christophe Leroy Signed-off-by: Naveen N Rao Signed-off-by: Michael Ellerman Link: https://msgid.link/20240110141237.3179199-1-naveen@kernel.org List of files: /linux-6.15/arch/powerpc/Makefile

ca3d3aa1 - powerpc: Remove cpu-as-y completely

Thu, 29 Feb 2024 12:25:21 +0000

powerpc: Remove cpu-as-y completelycpu-as-y is there to force assembler building options. But there is noneed for that. GCC is passed the necessary options and it automaticallypass the appropriate option to GAS.GCC is given -maltivec when relevant, so no need for -Wa,-maltiveceither.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 960e30029863("powerpc/Makefile: Fix PPC_BOOK3S_64 ASFLAGS") in order to fix an issuewith clang and the passed -Wa,-mpower4 option. But we have now removedit expecting the compiler to automatically pass the proper options andinstructions based on -mcpu=power4.Signed-off-by: Christophe Leroy Acked-by: Segher Boessenkool Signed-off-by: Michael Ellerman Link: https://msgid.link/20240229122521.762431-5-mpe@ellerman.id.au List of files: /linux-6.15/arch/powerpc/Makefile

af1ebca5 - powerpc: Add allmodconfig for all 32-bit sub-arches

Thu, 29 Feb 2024 11:41:08 +0000

powerpc: Add allmodconfig for all 32-bit sub-arches32-bit powerpc kernels can be built for one of 5 sub-arches, seeKconfig.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 buildcoverage: ppc40x_allmodconfig ppc44x_allmodconfig ppc8xx_allmodconfig ppc85xx_allmodconfigAcked-by: Uwe Kleine-König Signed-off-by: Michael Ellerman Link: https://msgid.link/20240229114108.743810-1-mpe@ellerman.id.au List of files: /linux-6.15/arch/powerpc/Makefile

2947a456 - treewide: update LLVM Bugzilla links

Tue, 09 Jan 2024 22:16:31 +0000

treewide: update LLVM Bugzilla linksLLVM moved their issue tracker from their own Bugzilla instance to GitHubissues. While all of the links are still valid, they may not necessarilyshow the most up to date information around the issues, as all updateswill occur on GitHub, not Bugzilla.Another complication is that the Bugzilla issue number is not always thesame as the GitHub issue number. Thankfully, LLVM maintains this mappingthrough two shortlinks: https://llvm.org/bz -> https://bugs.llvm.org/show_bug.cgi?id= https://llvm.org/pr -> https://github.com/llvm/llvm-project/issues/Switch all "https://bugs.llvm.org/show_bug.cgi?id=" links to the"https://llvm.org/pr" shortlink so that the links show the most up todate information. Each migrated issue links back to the Bugzilla entry,so there should be no loss of fidelity of information here.Link: https://lkml.kernel.org/r/20240109-update-llvm-links-v1-3-eb09b59db071@kernel.orgSigned-off-by: Nathan Chancellor Reviewed-by: Kees Cook Acked-by: Fangrui Song Cc: Alexei Starovoitov Cc: Andrii Nakryiko Cc: Daniel Borkmann Cc: Mykola Lysenko Signed-off-by: Andrew Morton List of files: /linux-6.15/arch/powerpc/Makefile

402928b5 - powerpc/Makefile: Auto detect cross compiler

Wed, 06 Dec 2023 11:55:48 +0000

powerpc/Makefile: Auto detect cross compilerIf 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 compileron Fedora and Ubuntu (which use linux-gnu-), and also detects thekernel.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 4Inspired by arch/parisc/Makefile.Acked-by: Segher Boessenkool Signed-off-by: Michael Ellerman Link: https://msgid.link/20231206115548.1466874-4-mpe@ellerman.id.au List of files: /linux-6.15/arch/powerpc/Makefile

22f17b02 - powerpc/Makefile: Default to ppc64le_defconfig when cross building

Wed, 06 Dec 2023 11:55:47 +0000

powerpc/Makefile: Default to ppc64le_defconfig when cross buildingIf the kernel is being cross compiled, there is no information fromuname on which defconfig is most appropriate, so the Makefile defaultsto ppc64.However these days almost all distros that support powerpc are littleendian, so it's more likely that defaulting to ppc64le_defconfig willproduce something useful for a user.Signed-off-by: Michael Ellerman Link: https://msgid.link/20231206115548.1466874-3-mpe@ellerman.id.au List of files: /linux-6.15/arch/powerpc/Makefile

dc420877 - powerpc/Makefile: Don't use $(ARCH) unnecessarily

Wed, 06 Dec 2023 11:55:45 +0000

powerpc/Makefile: Don't use $(ARCH) unnecessarilyThere's no need to use $(ARCH) for references to the arch directory inthe source tree, it is always arch/powerpc.Signed-off-by: Michael Ellerman Link: https://msgid.link/20231206115548.1466874-1-mpe@ellerman.id.au List of files: /linux-6.15/arch/powerpc/Makefile

50832720 - powerpc/64s: Move CPU -mtune options into Kconfig

Wed, 29 Mar 2023 23:43:08 +0000

powerpc/64s: Move CPU -mtune options into KconfigCurrently the -mtune options are set in the Makefile, depending on whatthe compiler supports.One downside of doing it that way is that the chosen -mtune option isnot recorded in the .config.Another downside is that if there's ever a need to do more complicatedlogic to calculate the correct option, that gets messy in the Makefile.So move the determination of which -mtune option to use into Kconfiglogic.Signed-off-by: Michael Ellerman Link: https://msgid.link/20230329234308.2215833-1-mpe@ellerman.id.au List of files: /linux-6.15/arch/powerpc/Makefile

0f71dcfb - powerpc/ftrace: Add support for -fpatchable-function-entry

Mon, 19 Jun 2023 09:47:34 +0000

powerpc/ftrace: Add support for -fpatchable-function-entryGCC v13.1 updated support for -fpatchable-function-entry on ppc64le toemit nops after the local entry point, rather than before it. Thisallows us to use this in the kernel for ftrace purposes. A new script isadded under arch/powerpc/tools/ to help detect if nops are emitted afterthe function local entry point, or before the global entry point.With -fpatchable-function-entry, we no longer have the profilinginstructions generated at function entry, so we only need to validatethe presence of two nops at the ftrace location in ftrace_init_nop(). Wepatch 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 -pgoption emits an additional 'stw' instruction after 'mflr r0' and beforethe 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'sstackframe. Subsequently, this additional store was removed in latercompiler versions for performance reasons. The same reasons apply forppc32 so we only patch in a 'mflr r0'.Signed-off-by: Naveen N Rao Reviewed-by: Christophe Leroy Signed-off-by: Michael Ellerman Link: https://msgid.link/68586d22981a2c3bb45f27a2b621173d10a7d092.1687166935.git.naveen@kernel.org List of files: /linux-6.15/arch/powerpc/Makefile

54a11654 - powerpc: remove checks for binutils older than 2.25

Thu, 19 Jan 2023 08:22:50 +0000

powerpc: remove checks for binutils older than 2.25Commit e4412739472b ("Documentation: raise minimum supported version ofbinutils to 2.25") allows us to remove the checks for old binutils.There is no more user for ld-ifversion. Remove it as well.Signed-off-by: Masahiro Yamada Reviewed-by: Nicholas Piggin Signed-off-by: Michael Ellerman Link: https://msgid.link/20230119082250.151485-1-masahiroy@kernel.org List of files: /linux-6.15/arch/powerpc/Makefile

25ea739e - powerpc: Fail build if using recordmcount with binutils v2.37

Tue, 30 May 2023 06:14:36 +0000

powerpc: Fail build if using recordmcount with binutils v2.37binutils v2.37 drops unused section symbols, which prevents recordmcountfrom capturing mcount locations in sections that have no non-weaksymbols. 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: failedThe change to binutils was reverted for v2.38, so this behavior isspecific to binutils v2.37:https://sourceware.org/git/?p=binutils-gdb.git;a=commit;h=c09c8b42021180eee9495bd50d8b35e683d3901bObjtool is able to cope with such sections, so this issue is specific torecordmcount.Fail the build and print a warning if binutils v2.37 is detected and ifwe are using recordmcount.Cc: stable@vger.kernel.orgSuggested-by: Joel Stanley Signed-off-by: Naveen N Rao Signed-off-by: Michael Ellerman Link: https://msgid.link/20230530061436.56925-1-naveen@kernel.org List of files: /linux-6.15/arch/powerpc/Makefile

f5df87b8 - powerpc/build: Remove -pipe from compilation flags

Tue, 06 Jun 2023 06:48:30 +0000

powerpc/build: Remove -pipe from compilation flagsx86 removed -pipe in commit 437e88ab8f9e2 ("x86/build: Remove -pipe fromKBUILD_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 systemwas in the noise after 10 builds each. No point in adding options unlessthey help something, so remove it.Signed-off-by: Nicholas Piggin Signed-off-by: Michael Ellerman Link: https://msgid.link/20230606064830.184083-1-npiggin@gmail.com List of files: /linux-6.15/arch/powerpc/Makefile