kernel/linux.git/arch/arm64/Makefile, branch v5.15.208

arm64: Force position-independent veneers

2024-11-01T00:52:35+00:00

[ Upstream commit 9abe390e689f4f5c23c5f507754f8678431b4f72 ] Certain portions of code always need to be position-independent regardless of CONFIG_RELOCATABLE, including code which is executed in an idmap or which is executed before relocations are applied. In some kernel configurations the LLD linker generates position-dependent veneers for such code, and when executed these result in early boot-time failures. Marc Zyngier encountered a boot failure resulting from this when building a (particularly cursed) configuration with LLVM, as he reported to the list: https://lore.kernel.org/linux-arm-kernel/86wmjwvatn.wl-maz@kernel.org/ In Marc's kernel configuration, the .head.text and .rodata.text sections end up more than 128MiB apart, requiring a veneer to branch between the two: | [mark@lakrids:~/src/linux]% usekorg 14.1.0 aarch64-linux-objdump -t vmlinux | grep -w _text | ffff800080000000 g .head.text 0000000000000000 _text | [mark@lakrids:~/src/linux]% usekorg 14.1.0 aarch64-linux-objdump -t vmlinux | grep -w primary_entry | ffff8000889df0e0 g .rodata.text 000000000000006c primary_entry, ... consequently, LLD inserts a position-dependent veneer for the branch from _stext (in .head.text) to primary_entry (in .rodata.text): | ffff800080000000 <_text>: | ffff800080000000: fa405a4d ccmp x18, #0x0, #0xd, pl // pl = nfrst | ffff800080000004: 14003fff b ffff800080010000 <__AArch64AbsLongThunk_primary_entry> ... | ffff800080010000 <__AArch64AbsLongThunk_primary_entry>: | ffff800080010000: 58000050 ldr x16, ffff800080010008 <__AArch64AbsLongThunk_primary_entry+0x8> | ffff800080010004: d61f0200 br x16 | ffff800080010008: 889df0e0 .word 0x889df0e0 | ffff80008001000c: ffff8000 .word 0xffff8000 ... and as this is executed early in boot before the kernel is mapped in TTBR1 this results in a silent boot failure. Fix this by passing '--pic-veneer' to the linker, which will cause the linker to use position-independent veneers, e.g. | ffff800080000000 <_text>: | ffff800080000000: fa405a4d ccmp x18, #0x0, #0xd, pl // pl = nfrst | ffff800080000004: 14003fff b ffff800080010000 <__AArch64ADRPThunk_primary_entry> ... | ffff800080010000 <__AArch64ADRPThunk_primary_entry>: | ffff800080010000: f004e3f0 adrp x16, ffff800089c8f000 <__idmap_text_start> | ffff800080010004: 91038210 add x16, x16, #0xe0 | ffff800080010008: d61f0200 br x16 I've opted to pass '--pic-veneer' unconditionally, as: * In addition to solving the boot failure, these sequences are generally nicer as they require fewer instructions and don't need to perform data accesses. * While the position-independent veneer sequences have a limited +/-2GiB range, this is not a new restriction. Even kernels built with CONFIG_RELOCATABLE=n are limited to 2GiB in size as we have several structues using 32-bit relative offsets and PPREL32 relocations, which are similarly limited to +/-2GiB in range. These include extable entries, jump table entries, and alt_instr entries. * GNU LD defaults to using position-independent veneers, and supports the same '--pic-veneer' option, so this change is not expected to adversely affect GNU LD. I've tested with GNU LD 2.30 to 2.42 inclusive and LLVM 13.0.1 to 19.1.0 inclusive, using the kernel.org binaries from: * https://mirrors.edge.kernel.org/pub/tools/crosstool/ * https://mirrors.edge.kernel.org/pub/tools/llvm/ Signed-off-by: Mark Rutland Reported-by: Marc Zyngier Cc: Ard Biesheuvel Cc: Nathan Chancellor Cc: Nick Desaulniers Cc: Will Deacon Acked-by: Ard Biesheuvel Reviewed-by: Nathan Chancellor Link: https://lore.kernel.org/r/20240927101838.3061054-1-mark.rutland@arm.com Signed-off-by: Catalin Marinas Signed-off-by: Sasha Levin

Merge tag 'arm64-upstream' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux

2021-09-01T22:04:29+00:00

Pull arm64 updates from Catalin Marinas: - Support for 32-bit tasks on asymmetric AArch32 systems (on top of the scheduler changes merged via the tip tree). - More entry.S clean-ups and conversion to C. - MTE updates: allow a preferred tag checking mode to be set per CPU (the overhead of synchronous mode is smaller for some CPUs than others); optimisations for kernel entry/exit path; optionally disable MTE on the kernel command line. - Kselftest improvements for SVE and signal handling, PtrAuth. - Fix unlikely race where a TLBI could use stale ASID on an ASID roll-over (found by inspection). - Miscellaneous fixes: disable trapping of PMSNEVFR_EL1 to higher exception levels; drop unnecessary sigdelsetmask() call in the signal32 handling; remove BUG_ON when failing to allocate SVE state (just signal the process); SYM_CODE annotations. - Other trivial clean-ups: use macros instead of magic numbers, remove redundant returns, typos. * tag 'arm64-upstream' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux: (56 commits) arm64: Do not trap PMSNEVFR_EL1 arm64: mm: fix comment typo of pud_offset_phys() arm64: signal32: Drop pointless call to sigdelsetmask() arm64/sve: Better handle failure to allocate SVE register storage arm64: Document the requirement for SCR_EL3.HCE arm64: head: avoid over-mapping in map_memory arm64/sve: Add a comment documenting the binutils needed for SVE asm arm64/sve: Add some comments for sve_save/load_state() kselftest/arm64: signal: Add a TODO list for signal handling tests kselftest/arm64: signal: Add test case for SVE register state in signals kselftest/arm64: signal: Verify that signals can't change the SVE vector length kselftest/arm64: signal: Check SVE signal frame shows expected vector length kselftest/arm64: signal: Support signal frames with SVE register data kselftest/arm64: signal: Add SVE to the set of features we can check for arm64: replace in_irq() with in_hardirq() kselftest/arm64: pac: Fix skipping of tests on systems without PAC Documentation: arm64: describe asymmetric 32-bit support arm64: Remove logic to kill 32-bit tasks on 64-bit-only cores arm64: Hook up cmdline parameter to allow mismatched 32-bit EL0 arm64: Advertise CPUs capable of running 32-bit applications in sysfs ...

Merge remote-tracking branch 'tip/sched/arm64' into for-next/core

2021-08-31T08:10:00+00:00

* tip/sched/arm64: (785 commits) Documentation: arm64: describe asymmetric 32-bit support arm64: Remove logic to kill 32-bit tasks on 64-bit-only cores arm64: Hook up cmdline parameter to allow mismatched 32-bit EL0 arm64: Advertise CPUs capable of running 32-bit applications in sysfs arm64: Prevent offlining first CPU with 32-bit EL0 on mismatched system arm64: exec: Adjust affinity for compat tasks with mismatched 32-bit EL0 arm64: Implement task_cpu_possible_mask() sched: Introduce dl_task_check_affinity() to check proposed affinity sched: Allow task CPU affinity to be restricted on asymmetric systems sched: Split the guts of sched_setaffinity() into a helper function sched: Introduce task_struct::user_cpus_ptr to track requested affinity sched: Reject CPU affinity changes based on task_cpu_possible_mask() cpuset: Cleanup cpuset_cpus_allowed_fallback() use in select_fallback_rq() cpuset: Honour task_cpu_possible_mask() in guarantee_online_cpus() cpuset: Don't use the cpu_possible_mask as a last resort for cgroup v1 sched: Introduce task_cpu_possible_mask() to limit fallback rq selection sched: Cgroup SCHED_IDLE support sched/topology: Skip updating masks for non-online nodes Linux 5.14-rc6 lib: use PFN_PHYS() in devmem_is_allowed() ...

arm64: clean vdso & vdso32 files

2021-08-11T10:04:55+00:00

commit a5b8ca97fbf8 ("arm64: do not descend to vdso directories twice") changes the cleaning behavior of arm64's vdso files, in that vdso.lds, vdso.so, and vdso.so.dbg are not removed upon a 'make clean/mrproper': $ make defconfig ARCH=arm64 $ make ARCH=arm64 $ make mrproper ARCH=arm64 $ git clean -nxdf Would remove arch/arm64/kernel/vdso/vdso.lds Would remove arch/arm64/kernel/vdso/vdso.so Would remove arch/arm64/kernel/vdso/vdso.so.dbg To remedy this, manually descend into arch/arm64/kernel/vdso upon cleaning. After this commit: $ make defconfig ARCH=arm64 $ make ARCH=arm64 $ make mrproper ARCH=arm64 $ git clean -nxdf Similar results are obtained for the vdso32 equivalent. Signed-off-by: Andrew Delgadillo Cc: stable@vger.kernel.org Fixes: a5b8ca97fbf8 ("arm64: do not descend to vdso directories twice") Link: https://lore.kernel.org/r/20210810231755.1743524-1-adelg@google.com Signed-off-by: Will Deacon

arm64: move the (z)install rules to arch/arm64/Makefile

2021-08-03T15:19:03+00:00

Currently, the (z)install targets in arch/arm64/Makefile descend into arch/arm64/boot/Makefile to invoke the shell script, but there is no good reason to do so. arch/arm64/Makefile can run the shell script directly. Signed-off-by: Masahiro Yamada Link: https://lore.kernel.org/r/20210729140527.443116-1-masahiroy@kernel.org Signed-off-by: Catalin Marinas

arm64: move warning about toolchains to archprepare

2021-08-03T09:35:58+00:00

Commit 987fdfec2410 ("arm64: move --fix-cortex-a53-843419 linker test to Kconfig") fixed the false-positive warning in the installation step. Yet, there are some cases where this false-positive is shown. For example, you can see it when you cross 987fdfec2410 during git-bisect. $ git checkout 987fdfec2410^ [ snip ] $ make ARCH=arm64 CROSS_COMPILE=aarch64-linux-gnu- defconfig all [ snip ] $ git checkout v5.13 [ snip] $ make ARCH=arm64 CROSS_COMPILE=aarch64-linux-gnu- defconfig all [ snip ] arch/arm64/Makefile:25: ld does not support --fix-cortex-a53-843419; kernel may be susceptible to erratum In the stale include/config/auto.config, CONFIG_ARM64_ERRATUM_843419=y is set without CONFIG_ARM64_LD_HAS_FIX_ERRATUM_843419, so the warning is displayed while parsing the Makefiles. Make will restart with the updated include/config/auto.config, hence CONFIG_ARM64_LD_HAS_FIX_ERRATUM_843419 will be set eventually, but this warning is a surprise for users. Commit 25896d073d8a ("x86/build: Fix compiler support check for CONFIG_RETPOLINE") addressed a similar issue. Move $(warning ...) out of the parse stage of Makefiles. The same applies to CONFIG_ARM64_USE_LSE_ATOMICS. Signed-off-by: Masahiro Yamada Link: https://lore.kernel.org/r/20210801053525.105235-1-masahiroy@kernel.org Signed-off-by: Will Deacon

Merge tag 'kbuild-v5.14' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild

2021-07-10T18:01:38+00:00

Pull Kbuild updates from Masahiro Yamada: - Increase the -falign-functions alignment for the debug option. - Remove ugly libelf checks from the top Makefile. - Make the silent build (-s) more silent. - Re-compile the kernel if KBUILD_BUILD_TIMESTAMP is specified. - Various script cleanups * tag 'kbuild-v5.14' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild: (27 commits) scripts: add generic syscallnr.sh scripts: check duplicated syscall number in syscall table sparc: syscalls: use pattern rules to generate syscall headers parisc: syscalls: use pattern rules to generate syscall headers nds32: add arch/nds32/boot/.gitignore kbuild: mkcompile_h: consider timestamp if KBUILD_BUILD_TIMESTAMP is set kbuild: modpost: Explicitly warn about unprototyped symbols kbuild: remove trailing slashes from $(KBUILD_EXTMOD) kconfig.h: explain IS_MODULE(), IS_ENABLED() kconfig: constify long_opts scripts/setlocalversion: simplify the short version part scripts/setlocalversion: factor out 12-chars hash construction scripts/setlocalversion: add more comments to -dirty flag detection scripts/setlocalversion: remove workaround for old make-kpkg scripts/setlocalversion: remove mercurial, svn and git-svn supports kbuild: clean up ${quiet} checks in shell scripts kbuild: sink stdout from cmd for silent build init: use $(call cmd,) for generating include/generated/compile.h kbuild: merge scripts/mkmakefile to top Makefile sh: move core-y in arch/sh/Makefile to arch/sh/Kbuild ...

arm64: Add ARM64_PTR_AUTH_KERNEL config option

2021-06-15T10:32:31+00:00

This patch add the ARM64_PTR_AUTH_KERNEL config and deals with the build aspect of it. Userspace support has no dependency on the toolchain therefore all toolchain checks and build flags are controlled the new config option. The default config behavior will not be changed. Signed-off-by: Daniel Kiss Acked-by: Will Deacon Reviewed-by: Catalin Marinas Link: https://lore.kernel.org/r/20210613092632.93591-2-daniel.kiss@arm.com Signed-off-by: Will Deacon

kbuild: require all architectures to have arch/$(SRCARCH)/Kbuild

2021-05-26T14:10:37+00:00

arch/$(SRCARCH)/Kbuild is useful for Makefile cleanups because you can use the obj-y syntax. Add an empty file if it is missing in arch/$(SRCARCH)/. Signed-off-by: Masahiro Yamada

arm64: Generate cpucaps.h

2021-05-10T09:16:37+00:00

The arm64 code allocates an internal constant to every CPU feature it can detect, distinct from the public hwcap numbers we use to expose some features to userspace. Currently this is maintained manually which is an irritating source of conflicts when working on new features, to avoid this replace the header with a simple text file listing the names we've assigned and sort it to minimise conflicts. As part of doing this we also do the Kbuild hookup required to hook up an arch tools directory and to generate header files in there. This will result in a renumbering and reordering of the existing constants, since they are all internal only the values should not be important. The reordering will impact the order in which some steps in enumeration handle features but the algorithm is not intended to depend on this and I haven't seen any issues when testing. Due to the UAO cpucap having been removed in the past we end up with ARM64_NCAPS being 1 smaller than it was before. Signed-off-by: Mark Brown Reviewed-by: Mark Rutland Tested-by: Mark Rutland Link: https://lore.kernel.org/r/20210428121231.11219-1-broonie@kernel.org Signed-off-by: Catalin Marinas