Commit "mm/page_alloc: convert per-cpu list protection to local_lock" will
introduce a zero-sized per-CPU variable, which causes pahole to generate
invalid BTF. Only pahole versions 1.18 through 1.21 are impacted, as
before 1.18 pahole doesn't know anything about per-CPU variables, and 1.22
contains the proper fix for the issue.
Luckily, pahole 1.18 got --skip_encoding_btf_vars option disabling BTF
generation for per-CPU variables in anticipation of some unanticipated
problems. So use this escape hatch to disable per-CPU var BTF info on
those problematic pahole versions. Users relying on availability of
per-CPU var BTFs would need to upgrade to pahole 1.22+, but everyone won't
notice any regressions.
Link: https://lkml.kernel.org/r/20210530002536.3193829-1-andrii@kernel.org
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Mel Gorman <mgorman@techsingularity.net>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Hao Luo <haoluo@google.com>
Cc: Michal Suchanek <msuchanek@suse.de>
Cc: Jiri Olsa <jolsa@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Patch series "streamline_config.pl: Fix Perl spacing".
Talking with John Hawley about how vim and emacs deal with Perl files with
respect to tabs and spaces, I found that some of my Perl code in the
kernel had inconsistent spacing. The way emacs handles Perl by default is
to use 4 spaces per indent, but make all 8 spaces into a single tab. Vim
does not do this by default. But if you add the vim variable control:
# vim: softtabstop=4
to a perl file, it makes vim behave the same way as emacs.
The first patch is to change all 8 spaces into a single tab (mostly from
people editing the file with vim). The next patch adds the softtabstop
variable to make vim act like emacs by default.
This patch (of 2):
As Perl code tends to have 4 space indentation, but uses tabs for every 8
spaces, make that consistent in the streamline_config.pl code. Replace
all 8 spaces with a single tab.
Link: https://lkml.kernel.org/r/20210322214032.133596267@goodmis.org
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Cc: "John (Warthog9) Hawley" <warthog9@kernel.org>
Cc: Masahiro Yamada <masahiroy@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The ccache tool can be used to speed up cross-compilation, by calling the
compiler and binutils through ccache. For example, following should work:
$ export ARCH=arm64 CROSS_COMPILE="ccache aarch64-linux-gnu-"
$ make M=drivers/gpu/drm/rockchip/
but pahole fails to extract the BTF info from DWARF, breaking the build:
CC [M] drivers/gpu/drm/rockchip//rockchipdrm.mod.o
LD [M] drivers/gpu/drm/rockchip//rockchipdrm.ko
BTF [M] drivers/gpu/drm/rockchip//rockchipdrm.ko
aarch64-linux-gnu-objcopy: invalid option -- 'J'
Usage: aarch64-linux-gnu-objcopy [option(s)] in-file [out-file]
Copies a binary file, possibly transforming it in the process
...
make[1]: *** [scripts/Makefile.modpost:156: __modpost] Error 2
make: *** [Makefile:1866: modules] Error 2
this fails because OBJCOPY is set to "ccache aarch64-linux-gnu-copy" and
later pahole is executed with the following command line:
LLVM_OBJCOPY=$(OBJCOPY) $(PAHOLE) -J --btf_base vmlinux $@
which gets expanded to:
LLVM_OBJCOPY=ccache aarch64-linux-gnu-objcopy pahole -J ...
instead of:
LLVM_OBJCOPY="ccache aarch64-linux-gnu-objcopy" pahole -J ...
Fixes: 5f9ae91f7c ("kbuild: Build kernel module BTFs if BTF is enabled and pahole supports it")
Signed-off-by: Javier Martinez Canillas <javierm@redhat.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Link: https://lore.kernel.org/bpf/20210526215228.3729875-1-javierm@redhat.com
Commit 3fb0fdb3bb ("x86/stackprotector/32: Make the canary into a regular
percpu variable") modified the stackprotector check on 32-bit x86 to check
if gcc supports using %fs as canary. Adjust dummy-tools gcc script to pass
this new test by returning "%fs" rather than "%gs" if it detects
-mstack-protector-guard-reg=fs on command line.
Fixes: 3fb0fdb3bb ("x86/stackprotector/32: Make the canary into a regular percpu variable")
Signed-off-by: Michal Kubecek <mkubecek@suse.cz>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Pull more Kbuild updates from Masahiro Yamada:
- Convert sh and sparc to use generic shell scripts to generate the
syscall headers
- refactor .gitignore files
- Update kernel/config_data.gz only when the content of the .config
is really changed, which avoids the unneeded re-link of vmlinux
- move "remove stale files" workarounds to scripts/remove-stale-files
- suppress unused-but-set-variable warnings by default for Clang
as well
- fix locale setting LANG=C to LC_ALL=C
- improve 'make distclean'
- always keep intermediate objects from scripts/link-vmlinux.sh
- move IF_ENABLED out of <linux/kconfig.h> to make it self-contained
- misc cleanups
* tag 'kbuild-v5.13-2' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild: (25 commits)
linux/kconfig.h: replace IF_ENABLED() with PTR_IF() in <linux/kernel.h>
kbuild: Don't remove link-vmlinux temporary files on exit/signal
kbuild: remove the unneeded comments for external module builds
kbuild: make distclean remove tag files in sub-directories
kbuild: make distclean work against $(objtree) instead of $(srctree)
kbuild: refactor modname-multi by using suffix-search
kbuild: refactor fdtoverlay rule
kbuild: parameterize the .o part of suffix-search
arch: use cross_compiling to check whether it is a cross build or not
kbuild: remove ARCH=sh64 support from top Makefile
.gitignore: prefix local generated files with a slash
kbuild: replace LANG=C with LC_ALL=C
Makefile: Move -Wno-unused-but-set-variable out of GCC only block
kbuild: add a script to remove stale generated files
kbuild: update config_data.gz only when the content of .config is changed
.gitignore: ignore only top-level modules.builtin
.gitignore: move tags and TAGS close to other tag files
kernel/.gitgnore: remove stale timeconst.h and hz.bc
usr/include: refactor .gitignore
genksyms: fix stale comment
...
arm64 uses SP_EL0 to save the current task_struct address. While running
in EL0, SP_EL0 is clobbered by userspace. So if the upper bit is not 1
(not TTBR1), the current address is invalid. This patch checks the upper
bit of SP_EL0, if the upper bit is 1, lx_current() of arm64 will return
the derefrence of current task. Otherwise, lx_current() will tell users
they are running in userspace(EL0).
While arm64 is running in EL0, it is actually pointless to print current
task as the memory of kernel space is not accessible in EL0.
Link: https://lkml.kernel.org/r/20210314203444.15188-3-song.bao.hua@hisilicon.com
Signed-off-by: Barry Song <song.bao.hua@hisilicon.com>
Cc: Jan Kiszka <jan.kiszka@siemens.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Kieran Bingham <kbingham@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Patch series "scripts/gdb: clarify the platforms supporting lx_current and add arm64 support", v2.
lx_current depends on per_cpu current_task variable which exists on x86
only. so it actually works on x86 only. the 1st patch documents this
clearly; the 2nd patch adds support for arm64.
This patch (of 2):
x86 is the only architecture which has per_cpu current_task:
arch$ git grep current_task | grep -i per_cpu
x86/include/asm/current.h:DECLARE_PER_CPU(struct task_struct *, current_task);
x86/kernel/cpu/common.c:DEFINE_PER_CPU(struct task_struct *, current_task) ____cacheline_aligned =
x86/kernel/cpu/common.c:EXPORT_PER_CPU_SYMBOL(current_task);
x86/kernel/cpu/common.c:DEFINE_PER_CPU(struct task_struct *, current_task) = &init_task;
x86/kernel/cpu/common.c:EXPORT_PER_CPU_SYMBOL(current_task);
x86/kernel/smpboot.c: per_cpu(current_task, cpu) = idle;
On other architectures, lx_current() will lead to a python exception:
(gdb) p $lx_current().pid
Python Exception <class 'gdb.error'> No symbol "current_task" in current context.:
Error occurred in Python: No symbol "current_task" in current context.
To avoid more people struggling and wasting time in other architectures,
document it.
Link: https://lkml.kernel.org/r/20210314203444.15188-1-song.bao.hua@hisilicon.com
Link: https://lkml.kernel.org/r/20210314203444.15188-2-song.bao.hua@hisilicon.com
Signed-off-by: Barry Song <song.bao.hua@hisilicon.com>
Cc: Jan Kiszka <jan.kiszka@siemens.com>
Cc: Kieran Bingham <kbingham@kernel.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Pull RISC-V updates from Palmer Dabbelt:
- Support for the memtest= kernel command-line argument.
- Support for building the kernel with FORTIFY_SOURCE.
- Support for generic clockevent broadcasts.
- Support for the buildtar build target.
- Some build system cleanups to pass more LLVM-friendly arguments.
- Support for kprobes.
- A rearranged kernel memory map, the first part of supporting sv48
systems.
- Improvements to kexec, along with support for kdump and crash
kernels.
- An alternatives-based errata framework, along with support for
handling a pair of errata that manifest on some SiFive designs
(including the HiFive Unmatched).
- Support for XIP.
- A device tree for the Microchip PolarFire ICICLE SoC and associated
dev board.
... along with a bunch of cleanups. There are already a handful of fixes
on the list so there will likely be a part 2.
* tag 'riscv-for-linus-5.13-mw0' of git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux: (45 commits)
RISC-V: Always define XIP_FIXUP
riscv: Remove 32b kernel mapping from page table dump
riscv: Fix 32b kernel build with CONFIG_DEBUG_VIRTUAL=y
RISC-V: Fix error code returned by riscv_hartid_to_cpuid()
RISC-V: Enable Microchip PolarFire ICICLE SoC
RISC-V: Initial DTS for Microchip ICICLE board
dt-bindings: riscv: microchip: Add YAML documentation for the PolarFire SoC
RISC-V: Add Microchip PolarFire SoC kconfig option
RISC-V: enable XIP
RISC-V: Add crash kernel support
RISC-V: Add kdump support
RISC-V: Improve init_resources()
RISC-V: Add kexec support
RISC-V: Add EM_RISCV to kexec UAPI header
riscv: vdso: fix and clean-up Makefile
riscv/mm: Use BUG_ON instead of if condition followed by BUG.
riscv/kprobe: fix kernel panic when invoking sys_read traced by kprobe
riscv: Set ARCH_HAS_STRICT_MODULE_RWX if MMU
riscv: module: Create module allocations without exec permissions
riscv: bpf: Avoid breaking W^X
...
Pull documentation fixes from Jonathan Corbet:
"A few late-arriving documentation fixes, including some oprofile
cleanup, a kernel-doc fix, some regression-reporting updates, and the
usual minor fixes"
* tag 'docs-5.13-2' of git://git.lwn.net/linux:
Enlisted oprofile version line removed
oprofiled version output line removed from the list
Removed the oprofiled version option
docs: reporting-issues.rst: CC subsystem and maintainers on regressions
docs: correct URL to bios and kernel developer's guide
docs/core-api: Consistent code style
docs/zh_CN: Adjust order and content of zh_CN/index.rst
Documentation: input: joydev file corrections
docs: Fix typo in Documentation/x86/x86_64/5level-paging.rst
kernel-doc: Add support for __deprecated
Keep them around until they are cleaned up by make clean. This
uses a bit more disk space, but makes it easier to debug any
problems with the kernel link process.
Suggested-by: Masahiro Yamada <masahiroy@kernel.org>
Signed-off-by: Andi Kleen <ak@linux.intel.com>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Rename overlay-y to multi-dtb-y, which is a consistent name with
multi-obj-y. Also, use multi-search to avoid code duplication.
Introduce real-dtb-y, which is a consistent name with real-obj-y,
to contain primitive blobs compiled from *.dts. This is used to
calculate the list of *.dt.yaml files.
Set -@ to base DTB without using $(eval ).
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
The suffix-search macro hard-codes the suffix, '.o'.
Make it a parameter so that the multi-search and real-search macros
can be reused for foo-dtbs syntax introduced by commit 15d16d6dad
("kbuild: Add generic rule to apply fdtoverlay").
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
