commit 90ceddcb495008ac8ba7a3dce297841efcd7d584 upstream.
Simplify gen_btf logic to make it work with llvm-objcopy. The existing
'file format' and 'architecture' parsing logic is brittle and does not
work with llvm-objcopy/llvm-objdump.
'file format' output of llvm-objdump>=11 will match GNU objdump, but
'architecture' (bfdarch) may not.
.BTF in .tmp_vmlinux.btf is non-SHF_ALLOC. Add the SHF_ALLOC flag
because it is part of vmlinux image used for introspection. C code
can reference the section via linker script defined __start_BTF and
__stop_BTF. This fixes a small problem that previous .BTF had the
SHF_WRITE flag (objcopy -I binary -O elf* synthesized .data).
Additionally, `objcopy -I binary` synthesized symbols
_binary__btf_vmlinux_bin_start and _binary__btf_vmlinux_bin_stop (not
used elsewhere) are replaced with more commonplace __start_BTF and
__stop_BTF.
Add 2>/dev/null because GNU objcopy (but not llvm-objcopy) warns
"empty loadable segment detected at vaddr=0xffffffff81000000, is this intentional?"
We use a dd command to change the e_type field in the ELF header from
ET_EXEC to ET_REL so that lld will accept .btf.vmlinux.bin.o. Accepting
ET_EXEC as an input file is an extremely rare GNU ld feature that lld
does not intend to support, because this is error-prone.
The output section description .BTF in include/asm-generic/vmlinux.lds.h
avoids potential subtle orphan section placement issues and suppresses
--orphan-handling=warn warnings.
Fixes: df786c9b9476 ("bpf: Force .BTF section start to zero when dumping from vmlinux")
Fixes: cb0cc635c7a9 ("powerpc: Include .BTF section")
Reported-by: Nathan Chancellor <natechancellor@gmail.com>
Change-Id: I145b50cfe3e0e1e034fb750cf55642905382a06c
Signed-off-by: Fangrui Song <maskray@google.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Tested-by: Stanislav Fomichev <sdf@google.com>
Tested-by: Andrii Nakryiko <andriin@fb.com>
Reviewed-by: Stanislav Fomichev <sdf@google.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Acked-by: Andrii Nakryiko <andriin@fb.com>
Acked-by: Michael Ellerman <mpe@ellerman.id.au> (powerpc)
Link: https://github.com/ClangBuiltLinux/linux/issues/871
Link: https://lore.kernel.org/bpf/20200318222746.173648-1-maskray@google.com
Signed-off-by: Maria Teguiani <teguiani@google.com>
Tested-by: Matthias Maennich <maennich@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sorayukii <sorayukii69@gmail.com>
Fangrui Songauthored and Sorayukiicommited 2026-05-15 17:58:11 +07:00
Expose kernel's BTF under the name vmlinux to be more uniform with using
kernel module names as file names in the future.
Fixes: 341dfcf8d78e ("btf: expose BTF info through sysfs")
Suggested-by: Daniel Borkmann <daniel@iogearbox.net>
Change-Id: I0c478e34bd67044a37b166b60c1de07025c3ec90
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: Sorayukii <sorayukii69@gmail.com>
Andrii Nakryikoauthored and Sorayukiicommited 2026-05-15 17:58:05 +07:00
Make .BTF section allocated and expose its contents through sysfs.
/sys/kernel/btf directory is created to contain all the BTFs present
inside kernel. Currently there is only kernel's main BTF, represented as
/sys/kernel/btf/kernel file. Once kernel modules' BTFs are supported,
each module will expose its BTF as /sys/kernel/btf/<module-name> file.
Current approach relies on a few pieces coming together:
1. pahole is used to take almost final vmlinux image (modulo .BTF and
kallsyms) and generate .BTF section by converting DWARF info into
BTF. This section is not allocated and not mapped to any segment,
though, so is not yet accessible from inside kernel at runtime.
2. objcopy dumps .BTF contents into binary file and subsequently
convert binary file into linkable object file with automatically
generated symbols _binary__btf_kernel_bin_start and
_binary__btf_kernel_bin_end, pointing to start and end, respectively,
of BTF raw data.
3. final vmlinux image is generated by linking this object file (and
kallsyms, if necessary). sysfs_btf.c then creates
/sys/kernel/btf/kernel file and exposes embedded BTF contents through
it. This allows, e.g., libbpf and bpftool access BTF info at
well-known location, without resorting to searching for vmlinux image
on disk (location of which is not standardized and vmlinux image
might not be even available in some scenarios, e.g., inside qemu
during testing).
Alternative approach using .incbin assembler directive to embed BTF
contents directly was attempted but didn't work, because sysfs_proc.o is
not re-compiled during link-vmlinux.sh stage. This is required, though,
to update embedded BTF data (initially empty data is embedded, then
pahole generates BTF info and we need to regenerate sysfs_btf.o with
updated contents, but it's too late at that point).
If BTF couldn't be generated due to missing or too old pahole,
sysfs_btf.c handles that gracefully by detecting that
_binary__btf_kernel_bin_start (weak symbol) is 0 and not creating
/sys/kernel/btf at all.
v2->v3:
- added Documentation/ABI/testing/sysfs-kernel-btf (Greg K-H);
- created proper kobject (btf_kobj) for btf directory (Greg K-H);
- undo v2 change of reusing vmlinux, as it causes extra kallsyms pass
due to initially missing __binary__btf_kernel_bin_{start/end} symbols;
v1->v2:
- allow kallsyms stage to re-use vmlinux generated by gen_btf();
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Change-Id: Ife57356dd14b9ae0d2e3801eea7c602c6245952f
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: Sorayukii <sorayukii69@gmail.com>
Andrii Nakryikoauthored and Sorayukiicommited 2026-05-15 17:58:05 +07:00
When CONFIG_DEBUG_INFO_BTF is enabled but available version of pahole is too
old to support BTF generation, build script is supposed to emit warning and
proceed with the build. Due to using exit instead of return from BASH function,
existing handling code prematurely exits exit code 0, not completing some of
the build steps. This patch fixes issue by correctly returning just from
gen_btf() function only.
Fixes: e83b9f55448a ("kbuild: add ability to generate BTF type info for vmlinux")
Cc: Masahiro Yamada <yamada.masahiro@socionext.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: Alexei Starovoitov <ast@fb.com>
Cc: Yonghong Song <yhs@fb.com>
Cc: Martin KaFai Lau <kafai@fb.com>
Change-Id: If817e5a03a739213cecde92b827550b1de86d296
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Acked-by: Song Liu <songliubraving@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: Sorayukii <sorayukii69@gmail.com>
Andrii Nakryikoauthored and Sorayukiicommited 2026-05-15 17:58:04 +07:00
When BTF generation is enabled through CONFIG_DEBUG_INFO_BTF,
scripts/link-vmlinux.sh detects if pahole version is too old and
gracefully continues build process, skipping BTF generation build step.
But if pahole is not available, build will still fail. This patch adds
check for whether pahole exists at all and bails out gracefully, if not.
Cc: Alexei Starovoitov <ast@fb.com>
Reported-by: Yonghong Song <yhs@fb.com>
Fixes: e83b9f55448a ("kbuild: add ability to generate BTF type info for vmlinux")
Change-Id: I89e477f03aba8e16789b2a330469b2ac562df4d5
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: Sorayukii <sorayukii69@gmail.com>
Andrii Nakryikoauthored and Sorayukiicommited 2026-05-15 17:58:04 +07:00
This patch adds new config option to trigger generation of BTF type
information from DWARF debuginfo for vmlinux and kernel modules through
pahole, which in turn relies on libbpf for btf_dedup() algorithm.
The intent is to record compact type information of all types used
inside kernel, including all the structs/unions/typedefs/etc. This
enables BPF's compile-once-run-everywhere ([0]) approach, in which
tracing programs that are inspecting kernel's internal data (e.g.,
struct task_struct) can be compiled on a system running some kernel
version, but would be possible to run on other kernel versions (and
configurations) without recompilation, even if the layout of structs
changed and/or some of the fields were added, removed, or renamed.
This is only possible if BPF loader can get kernel type info to adjust
all the offsets correctly. This patch is a first time in this direction,
making sure that BTF type info is part of Linux kernel image in
non-loadable ELF section.
BTF deduplication ([1]) algorithm typically provides 100x savings
compared to DWARF data, so resulting .BTF section is not big as is
typically about 2MB in size.
[0] http://vger.kernel.org/lpc-bpf2018.html#session-2
[1] https://facebookmicrosites.github.io/bpf/blog/2018/11/14/btf-enhancement.html
Cc: Masahiro Yamada <yamada.masahiro@socionext.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: Alexei Starovoitov <ast@fb.com>
Cc: Yonghong Song <yhs@fb.com>
Cc: Martin KaFai Lau <kafai@fb.com>
Change-Id: Id935f6e3ac658d9a92d55acd39e8287c644c941d
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Acked-by: David S. Miller <davem@davemloft.net>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: Sorayukii <sorayukii69@gmail.com>
Andrii Nakryikoauthored and Sorayukiicommited 2026-05-15 17:58:04 +07:00
Fix error "kallsyms failure: relative symbol value 0xffffff8008080000 out of range in relative mode"
Change-Id: I5ea6ca54ba0fbf8714b0641e181e1dc99778d88b
Signed-off-by: Sorayukii <sorayukii69@gmail.com>
vutung2311authored and Sorayukiicommited 2026-05-15 17:48:21 +07:00
Add flags for the compilation of RTIC MP. Additional
checks to ensure rtic mp failure does not cause
kernel compilation to fail.
Change-Id: I01c87f848c24b31092b8871f6188ace4a4803ec9
Signed-off-by: Preeti Nagar <pnagar@codeaurora.org>
* refs/heads/tmp-b324a70:
Linux 4.9.86
MIPS: Implement __multi3 for GCC7 MIPS64r6 builds
KVM: arm/arm64: Fix check for hugepage size when allocating at Stage 2
net: gianfar_ptp: move set_fipers() to spinlock protecting area
sctp: make use of pre-calculated len
xen/gntdev: Fix partial gntdev_mmap() cleanup
xen/gntdev: Fix off-by-one error when unmapping with holes
SolutionEngine771x: fix Ether platform data
mdio-sun4i: Fix a memory leak
xen-netfront: enable device after manual module load
bnxt_en: Fix the 'Invalid VF' id check in bnxt_vf_ndo_prep routine.
can: flex_can: Correct the checking for frame length in flexcan_start_xmit()
mac80211: mesh: drop frames appearing to be from us
nl80211: Check for the required netlink attribute presence
i40e/i40evf: Account for frags split over multiple descriptors in check linearize
uapi libc compat: add fallback for unsupported libcs
drm/ttm: check the return value of kzalloc
NET: usb: qmi_wwan: add support for YUGA CLM920-NC5 PID 0x9625
e1000: fix disabling already-disabled warning
macvlan: Fix one possible double free
xfs: quota: check result of register_shrinker()
xfs: quota: fix missed destroy of qi_tree_lock
IB/ipoib: Fix race condition in neigh creation
IB/mlx4: Fix mlx4_ib_alloc_mr error flow
s390/dasd: fix wrongly assigned configuration data
genirq: Guard handle_bad_irq log messages
IB/mlx5: Fix mlx5_ib_alloc_mr error flow
led: core: Fix brightness setting when setting delay_off=0
bnx2x: Improve reliability in case of nested PCI errors
tg3: Enable PHY reset in MTU change path for 5720
tg3: Add workaround to restrict 5762 MRRS to 2048
tipc: fix tipc_mon_delete() oops in tipc_enable_bearer() error path
tipc: error path leak fixes in tipc_enable_bearer()
lib/mpi: Fix umul_ppmm() for MIPS64r6
ARM: dts: ls1021a: fix incorrect clock references
scsi: storvsc: Fix scsi_cmd error assignments in storvsc_handle_error
net: stmmac: Fix TX timestamp calculation
ip6_tunnel: get the min mtu properly in ip6_tnl_xmit
net: arc_emac: fix arc_emac_rx() error paths
net: mediatek: setup proper state for disabled GMAC on the default
ASoC: nau8825: fix issue that pop noise when start capture
spi: atmel: fixed spin_lock usage inside atmel_spi_remove
mac80211_hwsim: Fix a possible sleep-in-atomic bug in hwsim_get_radio_nl
drm/nouveau/pci: do a msi rearm on init
net: phy: xgene: disable clk on error paths
sget(): handle failures of register_shrinker()
x86/asm: Allow again using asm.h when building for the 'bpf' clang target
ARM: 8731/1: Fix csum_partial_copy_from_user() stack mismatch
ipv6: icmp6: Allow icmp messages to be looped back
mtd: nand: brcmnand: Zero bitflip is not an error
mtd: nand: gpmi: Fix failure when a erased page has a bitflip at BBM
net: usb: qmi_wwan: add Telit ME910 PID 0x1101 support
nvme: check hw sectors before setting chunk sectors
dmaengine: fsl-edma: disable clks on all error paths
f2fs: fix a bug caused by NULL extent tree
i2c: designware: must wait for enable
hrtimer: Ensure POSIX compliance (relative CLOCK_REALTIME hrtimers)
ANDROID: kbuild: change LTO into a choice
ANDROID: arm64: crypto: fix AES CE when built as a module
ANDROID: staging: lustre: fix filler function type
ANDROID: fs: logfs: fix filler function type
ANDROID: fs: gfs2: fix filler function type
ANDROID: fs: exofs: fix filler function type
ANDROID: fs: afs: fix filler function type
ANDROID: keychord: Check for write data size
media-device: fix ioctl function types
drivers/perf: arm_pmu: fix function type mismatch
dummycon: fix function types
fs: nfs: fix filler function type
mm: fix filler function type mismatch
mm: fix drain_local_pages function type
BACKPORT: vfs: pass type instead of fn to do_{loop,iter}_readv_writev()
arch/arm64/crypto: fix CFI in AES CE
arch/arm64/crypto: fix CFI in SHA CE
arm64: disable CFI for cpu_replace_ttbr1
v4l2-ioctl: fix function types for IOCTL_INFO_STD
UPSTREAM: module: Do not paper over type mismatches in module_param_call()
BACKPORT: treewide: Fix function prototypes for module_param_call()
UPSTREAM: module: Prepare to convert all module_param_call() prototypes
bpf: fix function type for __bpf_prog_run
kallsyms: strip the .cfi postfix from symbols with CONFIG_CFI_CLANG
add support for clang Control Flow Integrity (CFI)
HACK: init: ensure initcall ordering with LTO
xen/efi: don't use -fshort-wchar
drivers/misc: disable LTO for lkdtm_rodata.o
arm64: vdso: disable LTO
FROMLIST: BACKPORT: arm64: select ARCH_SUPPORTS_LTO_CLANG
FROMLIST: BACKPORT: arm64: disable RANDOMIZE_MODULE_REGION_FULL with LTO_CLANG
FROMLIST: arch/arm64/crypto: disable LTO for aes-ce-cipher.c
arm64: disable ARM64_ERRATUM_843419 for clang LTO
arm64: pass code model to LLVMgold
FROMLIST: BACKPORT: arm64: make mrs_s and msr_s macros work with LTO
FROMLIST: arm64: kvm: use -fno-jump-tables with clang
FROMLIST: efi/libstub: disable LTO
FROMLIST: scripts/mod: disable LTO for empty.c
FROMLIST: BACKPORT: kbuild: fix dynamic ftrace with clang LTO
FROMLIST: BACKPORT: kbuild: add support for clang LTO
FROMLIST: BACKPORT: arm64: add a workaround for GNU gold with ARM64_MODULE_PLTS
FROMLIST: arm64: explicitly pass --no-fix-cortex-a53-843419 to GNU gold
FROMLIST: kbuild: add __ld-ifversion and linker-specific macros
FROMLIST: kbuild: add ld-name macro
FROMLIST: BACKPORT: arm64: keep .altinstructions and .altinstr_replacement
arm64: fix LD_DEAD_CODE_DATA_ELIMINATION
FROMLIST: kbuild: fix LD_DEAD_CODE_DATA_ELIMINATION
FROMLIST: BACKPORT: kbuild: add __cc-ifversion and compiler-specific variants
FROMLIST: kbuild: add clang-version.sh
Revert "binder: add missing binder_unlock()"
Linux 4.9.85
x86/entry/64: Clear extra registers beyond syscall arguments, to reduce speculation attack surface
mm: fail get_vaddr_frames() for filesystem-dax mappings
mm: Fix devm_memremap_pages() collision handling
libnvdimm, dax: fix 1GB-aligned namespaces vs physical misalignment
IB/core: disable memory registration of filesystem-dax vmas
v4l2: disable filesystem-dax mapping support
mm: introduce get_user_pages_longterm
device-dax: implement ->split() to catch invalid munmap attempts
libnvdimm: fix integer overflow static analysis warning
fs/dax.c: fix inefficiency in dax_writeback_mapping_range()
mm: avoid spurious 'bad pmd' warning messages
X.509: fix NULL dereference when restricting key with unsupported_sig
binder: add missing binder_unlock()
drm/amdgpu: add new device to use atpx quirk
drm/amdgpu: Avoid leaking PM domain on driver unbind (v2)
drm/amdgpu: add atpx quirk handling (v2)
drm/amdgpu: Add dpm quirk for Jet PRO (v2)
usb: renesas_usbhs: missed the "running" flag in usb_dmac with rx path
usb: gadget: f_fs: Process all descriptors during bind
Revert "usb: musb: host: don't start next rx urb if current one failed"
usb: ldusb: add PIDs for new CASSY devices supported by this driver
usb: dwc3: gadget: Set maxpacket size for ep0 IN
drm/edid: Add 6 bpc quirk for CPT panel in Asus UX303LA
Add delay-init quirk for Corsair K70 RGB keyboards
arm64: Disable unhandled signal log messages by default
usb: ohci: Proper handling of ed_rm_list to handle race condition between usb_kill_urb() and finish_unlinks()
ohci-hcd: Fix race condition caused by ohci_urb_enqueue() and io_watchdog_func()
PCI/cxgb4: Extend T3 PCI quirk to T4+ devices
irqchip/gic-v3: Use wmb() instead of smb_wmb() in gic_raise_softirq()
x86/oprofile: Fix bogus GCC-8 warning in nmi_setup()
iio: adis_lib: Initialize trigger before requesting interrupt
iio: buffer: check if a buffer has been set up when poll is called
RDMA/uverbs: Protect from command mask overflow
PKCS#7: fix certificate chain verification
X.509: fix BUG_ON() when hash algorithm is unsupported
cfg80211: fix cfg80211_beacon_dup
scsi: ibmvfc: fix misdefined reserved field in ibmvfc_fcp_rsp_info
xtensa: fix high memory/reserved memory collision
netfilter: drop outermost socket lock in getsockopt()
ANDROID: sdcardfs: Set num in extension_details during make_item
Conflicts:
Makefile
arch/arm64/include/asm/arch_gicv3.h
arch/arm64/kernel/module.lds
drivers/usb/gadget/function/f_fs.c
scripts/link-vmlinux.sh
Change in module_param_call() definition requires alignment in:
drivers/hwtracing/coresight/coresight-event.c
drivers/media/radio/radio-iris-transport.c
drivers/power/reset/msm-poweroff.c
drivers/soc/qcom/wcnss/wcnss_wlan.c
drivers/video/fbdev/msm/mdss_dsi_status.c
Change-Id: I2fa32c39bd4ba8a132f8f8abc8132a2ceb32907a
Signed-off-by: Blagovest Kolenichev <bkolenichev@codeaurora.org>
With CONFIG_LTO_CLANG enabled, LLVM IR won't be compiled into object
files until modpost_link. This change postpones calls to recordmcount
until after this step.
In order to exclude ftrace_process_locs from inspection, we add a new
code section .text..ftrace, which we tell recordmcount to ignore, and
a __norecordmcount attribute for moving functions to this section.
Bug: 62093296
Bug: 67506682
Change-Id: Iba2c053968206acf533fadab1eb34a743b5088ee
(am from https://patchwork.kernel.org/patch/10060327/)
Signed-off-by: Sami Tolvanen <samitolvanen@google.com>
This change adds the configuration option CONFIG_LTO_CLANG, and
build system support for clang's Link Time Optimization (LTO). In
preparation for LTO support for other compilers, potentially common
parts of the changes are gated behind CONFIG_LTO instead.
With -flto, instead of object files, clang produces LLVM bitcode,
which is compiled into a native object at link time, allowing the
final binary to be optimized globally. For more details, see:
https://llvm.org/docs/LinkTimeOptimization.html
While the kernel normally uses GNU ld for linking, LLVM supports LTO
only with lld or GNU gold linkers. This patch set assumes gold will
be used with the LLVMgold plug-in to perform the LTO link step. Due
to potential incompatibilities with GNU ld, this change also adds
LDFINAL_vmlinux for using a different linker for the vmlinux_link
step, and defaults to using GNU ld.
Assuming LLVMgold.so is in LD_LIBRARY_PATH and CONFIG_LTO_CLANG has
been selected, an LTO kernel can be built simply by running make
CC=clang. LTO requires clang >= 5.0 and gold from binutils >= 2.27.
Bug: 62093296
Bug: 67506682
Change-Id: Ibcd9fc7ec501b4f30b43b4877897615645f8655f
(am from https://patchwork.kernel.org/patch/10060329/)
Signed-off-by: Sami Tolvanen <samitolvanen@google.com>
Added RTIC environmental variable check. If set, this will trigger
RTIC MPGen during the kernel build. MPGen generates and embeds the
kernel MP.s (measurement parameters) to the vmlinux. It has to be
called during the kernel build, before vmlinux is generated.
RTIC MP.s to be consumed by the RTIC TA.
Acked-by: Alex Mavrin <amavrin@qti.qualcomm.com>
Change-Id: Id64ae893f750337abbecfea0b461f2d3ae508d00
Signed-off-by: Arun Menon <avmenon@codeaurora.org>
ld -r is an incremental link used to create built-in.o files in build
subdirectories. It produces relocatable object files containing all
its input files, and these are are then pulled together and relocated
in the final link. Aside from the bloat, this constrains the final
link relocations, which has bitten large powerpc builds with
unresolvable relocations in the final link.
Alan Modra has recommended the kernel use thin archives for linking.
This is an alternative and means that the linker has more information
available to it when it links the kernel.
This patch enables a config option architectures can select, which
causes all built-in.o files to be built as thin archives. built-in.o
files in subdirectories do not get symbol table or index attached,
which improves speed and size. The final link pass creates a
built-in.o archive in the root output directory which includes the
symbol table and index. The linker then uses takes this file to link.
The --whole-archive linker option is required, because the linker now
has visibility to every individual object file, and it will otherwise
just completely avoid including those without external references
(consider a file with EXPORT_SYMBOL or initcall or hardware exceptions
as its only entry points). The traditional built works "by luck" as
built-in.o files are large enough that they're going to get external
references. However this optimisation is unpredictable for the kernel
(due to above external references), ineffective at culling unused, and
costly because the .o files have to be searched for references.
Superior alternatives for link-time culling should be used instead.
Build characteristics for inclink vs thinarc, on a small powerpc64le
pseries VM with a modest .config:
inclink thinarc
sizes
vmlinux 15 618 680 15 625 028
sum of all built-in.o 56 091 808 1 054 334
sum excluding root built-in.o 151 430
find -name built-in.o | xargs rm ; time make vmlinux
real 22.772s 21.143s
user 13.280s 13.430s
sys 4.310s 2.750s
- Final kernel pulled in only about 6K more, which shows how
ineffective the object file culling is.
- Build performance looks improved due to less pagecache activity.
On IO constrained systems it could be a bigger win.
- Build size saving is significant.
Side note, the toochain understands archives, so there's some tricks,
$ ar t built-in.o # list all files you linked with
$ size built-in.o # and their sizes
$ objdump -d built-in.o # disassembly (unrelocated) with filenames
Implementation by sfr, minor tweaks by npiggin.
Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michal Marek <mmarek@suse.com>
Stephen Rothwellauthored and Michal Marekcommited 2016-09-09 10:31:19 +02:00
This patch allows to build the whole kernel with GCC plugins. It was ported from
grsecurity/PaX. The infrastructure supports building out-of-tree modules and
building in a separate directory. Cross-compilation is supported too.
Currently the x86, arm, arm64 and uml architectures enable plugins.
The directory of the gcc plugins is scripts/gcc-plugins. You can use a file or a directory
there. The plugins compile with these options:
* -fno-rtti: gcc is compiled with this option so the plugins must use it too
* -fno-exceptions: this is inherited from gcc too
* -fasynchronous-unwind-tables: this is inherited from gcc too
* -ggdb: it is useful for debugging a plugin (better backtrace on internal
errors)
* -Wno-narrowing: to suppress warnings from gcc headers (ipa-utils.h)
* -Wno-unused-variable: to suppress warnings from gcc headers (gcc_version
variable, plugin-version.h)
The infrastructure introduces a new Makefile target called gcc-plugins. It
supports all gcc versions from 4.5 to 6.0. The scripts/gcc-plugin.sh script
chooses the proper host compiler (gcc-4.7 can be built by either gcc or g++).
This script also checks the availability of the included headers in
scripts/gcc-plugins/gcc-common.h.
The gcc-common.h header contains frequently included headers for GCC plugins
and it has a compatibility layer for the supported gcc versions.
The gcc-generate-*-pass.h headers automatically generate the registration
structures for GIMPLE, SIMPLE_IPA, IPA and RTL passes.
Note that 'make clean' keeps the *.so files (only the distclean or mrproper
targets clean all) because they are needed for out-of-tree modules.
Based on work created by the PaX Team.
Signed-off-by: Emese Revfy <re.emese@gmail.com>
Acked-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Michal Marek <mmarek@suse.com>
Emese Revfyauthored and Michal Marekcommited 2016-06-07 22:57:10 +02:00
Now that we no longer emit .stubs symbols into a section VMA loaded
at absolute address 0x1000, we can drop the ARM-specific override that
sets a lower limit based on CONFIG_PAGE_OFFSET, below which symbols are
filtered from the kallsyms output.
Acked-by: Nicolas Pitre <nico@linaro.org>
Acked-by: Chris Brandt <chris.brandt@renesas.com>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Ard Biesheuvelauthored and Russell Kingcommited 2016-04-07 21:57:15 +01:00
Pull kbuild updates from Michal Marek:
- make dtbs_install fix
- Error handling fix fixdep and link-vmlinux.sh
- __UNIQUE_ID fix for clang
- Fix for if_changed_* to suppress the "is up to date." message
- The kernel is built with -Werror=incompatible-pointer-types
* 'kbuild' of git://git.kernel.org/pub/scm/linux/kernel/git/mmarek/kbuild:
kbuild: Add option to turn incompatible pointer check into error
kbuild: suppress annoying "... is up to date." message
kbuild: fixdep: Check fstat(2) return value
scripts/link-vmlinux.sh: force error on kallsyms failure
Kbuild: provide a __UNIQUE_ID for clang
dtbsinstall: don't move target directory out of the way
Similar to how relative extables are implemented, it is possible to emit
the kallsyms table in such a way that it contains offsets relative to
some anchor point in the kernel image rather than absolute addresses.
On 64-bit architectures, it cuts the size of the kallsyms address table
in half, since offsets between kernel symbols can typically be expressed
in 32 bits. This saves several hundreds of kilobytes of permanent
.rodata on average. In addition, the kallsyms address table is no
longer subject to dynamic relocation when CONFIG_RELOCATABLE is in
effect, so the relocation work done after decompression now doesn't have
to do relocation updates for all these values. This saves up to 24
bytes (i.e., the size of a ELF64 RELA relocation table entry) per value,
which easily adds up to a couple of megabytes of uncompressed __init
data on ppc64 or arm64. Even if these relocation entries typically
compress well, the combined size reduction of 2.8 MB uncompressed for a
ppc64_defconfig build (of which 2.4 MB is __init data) results in a ~500
KB space saving in the compressed image.
Since it is useful for some architectures (like x86) to retain the
ability to emit absolute values as well, this patch also adds support
for capturing both absolute and relative values when
KALLSYMS_ABSOLUTE_PERCPU is in effect, by emitting absolute per-cpu
addresses as positive 32-bit values, and addresses relative to the
lowest encountered relative symbol as negative values, which are
subtracted from the runtime address of this base symbol to produce the
actual address.
Support for the above is enabled by default for all architectures except
IA-64 and Tile-GX, whose symbols are too far apart to capture in this
manner.
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Tested-by: Guenter Roeck <linux@roeck-us.net>
Reviewed-by: Kees Cook <keescook@chromium.org>
Tested-by: Kees Cook <keescook@chromium.org>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Michal Marek <mmarek@suse.cz>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Ard Biesheuvelauthored and Linus Torvaldscommited 2016-03-15 16:55:16 -07:00
scripts/kallsyms.c has a special --absolute-percpu command line option
which deals with the zero based per cpu offsets that are used when
building for SMP on x86_64. This means that the option should only be
passed in that case, so add a Kconfig symbol with the correct predicate,
and use that instead.
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Tested-by: Guenter Roeck <linux@roeck-us.net>
Reviewed-by: Kees Cook <keescook@chromium.org>
Tested-by: Kees Cook <keescook@chromium.org>
Acked-by: Rusty Russell <rusty@rustcorp.com.au>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Michal Marek <mmarek@suse.cz>
Cc: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Ard Biesheuvelauthored and Linus Torvaldscommited 2016-03-15 16:55:16 -07:00
Since the output of the invocation of scripts/kallsyms is piped directly
into the assembler, error messages it emits are visible on stderr, but
a non-zero return code is ignored, and the build simply proceeds in that
case. However, the resulting kernel is most likely broken, and will crash
at boot.
So instead, capture the output of kallsyms in a separate .S file, and pass
that to the assembler in a separate step.
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Michal Marek <mmarek@suse.com>
Ard Biesheuvelauthored and Michal Marekcommited 2016-02-08 20:45:09 +01:00
Similarly to commit fb1770aa78, with gcc 5
on Ubuntu and CONFIG_STATIC_LINK=y I was seeing these linker errors:
/usr/lib/gcc/x86_64-linux-gnu/5/../../../x86_64-linux-gnu/librt.a(timer_create.o): In function `__timer_create_new':
(.text+0xcd): undefined reference to `pthread_once'
/usr/lib/gcc/x86_64-linux-gnu/5/../../../x86_64-linux-gnu/librt.a(timer_create.o): In function `__timer_create_new':
(.text+0x126): undefined reference to `pthread_attr_init'
/usr/lib/gcc/x86_64-linux-gnu/5/../../../x86_64-linux-gnu/librt.a(timer_create.o): In function `__timer_create_new':
(.text+0x168): undefined reference to `pthread_attr_setdetachstate'
[...]
Obviously we also need -lpthread for librt.a.
Cc: stable@vger.kernel.org # 4.4
Signed-off-by: Vegard Nossum <vegard.nossum@oracle.com>
Signed-off-by: Richard Weinberger <richard@nod.at>
Vegard Nossumauthored and Richard Weinbergercommited 2016-01-10 21:49:48 +01:00
On gcc Ubuntu 4.8.4-2ubuntu1~14.04, linking vmlinux fails with:
arch/um/os-Linux/built-in.o: In function `os_timer_create':
/android/kernel/android/arch/um/os-Linux/time.c:51: undefined reference to `timer_create'
arch/um/os-Linux/built-in.o: In function `os_timer_set_interval':
/android/kernel/android/arch/um/os-Linux/time.c:84: undefined reference to `timer_settime'
arch/um/os-Linux/built-in.o: In function `os_timer_remain':
/android/kernel/android/arch/um/os-Linux/time.c:109: undefined reference to `timer_gettime'
arch/um/os-Linux/built-in.o: In function `os_timer_one_shot':
/android/kernel/android/arch/um/os-Linux/time.c:132: undefined reference to `timer_settime'
arch/um/os-Linux/built-in.o: In function `os_timer_disable':
/android/kernel/android/arch/um/os-Linux/time.c:145: undefined reference to `timer_settime'
This is because -lrt appears in the generated link commandline
after arch/um/os-Linux/built-in.o. Fix this by removing -lrt from
arch/um/Makefile and adding it to the UM-specific section of
scripts/link-vmlinux.sh.
Signed-off-by: Lorenzo Colitti <lorenzo@google.com>
Signed-off-by: Richard Weinberger <richard@nod.at>
Lorenzo Colittiauthored and Richard Weinbergercommited 2015-12-08 22:25:13 +01:00
When Kernel is executed in place from ROM, the symbol addresses can be
lower than the page offset.
Tested-by: Chanwoo Choi <cw00.choi@samsung.com>
Signed-off-by: Maxime Coquelin <mcoquelin.stm32@gmail.com>
Tested-by: Andreas Färber <afaerber@suse.de>
Signed-off-by: Michal Marek <mmarek@suse.cz>
Maxime Coquelinauthored and Michal Marekcommited 2015-05-21 19:17:44 +08:00
While building linux with dash shell:
LINK vmlinux
trap: SIGHUP: bad trap
/src/linux-4.0/Makefile:933: recipe for target 'vmlinux' failed
make[1]: *** [vmlinux] Error 1
See the following document for behavior of posix shell trap instruction:
http://pubs.opengroup.org/onlinepubs/000095399/utilities/trap.html
Cc: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Sylvain BERTRAND <sylvain.bertrand@gmail.com>
Signed-off-by: Michal Marek <mmarek@suse.cz>
Sylvain BERTRANDauthored and Michal Marekcommited 2015-05-07 12:42:03 +02:00
The Makefiles call the respective interpreter explicitly, but this makes
it easier to use the scripts manually.
Signed-off-by: Michal Marek <mmarek@suse.cz>
x86-64 has a problem: per-cpu variables are actually represented by
their absolute offsets within the per-cpu area, but the symbols are
not emitted as absolute. Thus kallsyms naively creates them as offsets
from _text, meaning their values change if the kernel is relocated
(especially noticeable with CONFIG_RANDOMIZE_BASE):
$ egrep ' (gdt_|_(stext|_per_cpu_))' /root/kallsyms.nokaslr
0000000000000000 D __per_cpu_start
0000000000004000 D gdt_page
0000000000014280 D __per_cpu_end
ffffffff810001c8 T _stext
ffffffff81ee53c0 D __per_cpu_offset
$ egrep ' (gdt_|_(stext|_per_cpu_))' /root/kallsyms.kaslr1
000000001f200000 D __per_cpu_start
000000001f204000 D gdt_page
000000001f214280 D __per_cpu_end
ffffffffa02001c8 T _stext
ffffffffa10e53c0 D __per_cpu_offset
Making them absolute symbols is the Right Thing, but requires fixes to
the relocs tool. So for the moment, we add a --absolute-percpu option
which makes them absolute from a kallsyms perspective:
$ egrep ' (gdt_|_(stext|_per_cpu_))' /proc/kallsyms # no KASLR
0000000000000000 A __per_cpu_start
000000000000a000 A gdt_page
0000000000013040 A __per_cpu_end
ffffffff802001c8 T _stext
ffffffff8099b180 D __per_cpu_offset
ffffffff809a3000 D __per_cpu_load
$ egrep ' (gdt_|_(stext|_per_cpu_))' /proc/kallsyms # With KASLR
0000000000000000 A __per_cpu_start
000000000000a000 A gdt_page
0000000000013040 A __per_cpu_end
ffffffff89c001c8 T _stext
ffffffff8a39d180 D __per_cpu_offset
ffffffff8a3a5000 D __per_cpu_load
Based-on-the-original-screenplay-by: Andy Honig <ahonig@google.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Acked-by: Kees Cook <keescook@chromium.org>
Actually CONFIG_PAGE_OFFSET isn't same with PAGE_OFFSET, so
it isn't easy to figue out PAGE_OFFSET defined in header
file from scripts.
Because CONFIG_PAGE_OFFSET may not be defined in some ARCHs(
64bit ARCH), or defined as bogus value in !MMU case, so
this patch only applys the filter on ARM when CONFIG_PAGE_OFFSET
is defined as the original problem is only on ARM.
Cc: <stable@vger.kernel.org>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Fixes: f6537f2f0e
Singed-off-by: Ming Lei <tom.leiming@gmail.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Ming Leiauthored and Rusty Russellcommited 2013-12-10 16:49:19 +10:30
This patch uses CONFIG_PAGE_OFFSET to filter symbols which
are not in kernel address space because these symbols are
generally for generating code purpose and can't be run at
kernel mode, so we needn't keep them in /proc/kallsyms.
For example, on ARM there are some symbols which may be
linked in relocatable code section, then perf can't parse
symbols any more from /proc/kallsyms, this patch fixes the
problem (introduced b9b32bf70f)
Cc: Russell King <linux@arm.linux.org.uk>
Cc: linux-arm-kernel@lists.infradead.org
Cc: Michal Marek <mmarek@suse.cz>
Signed-off-by: Ming Lei <tom.leiming@gmail.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Cc: stable@vger.kernel.org
Ming Leiauthored and Rusty Russellcommited 2013-11-02 09:13:02 +10:30
We have CONFIG_SYMBOL_PREFIX, which three archs define to the string
"_". But Al Viro broke this in "consolidate cond_syscall and
SYSCALL_ALIAS declarations" (in linux-next), and he's not the first to
do so.
Using CONFIG_SYMBOL_PREFIX is awkward, since we usually just want to
prefix it so something. So various places define helpers which are
defined to nothing if CONFIG_SYMBOL_PREFIX isn't set:
1) include/asm-generic/unistd.h defines __SYMBOL_PREFIX.
2) include/asm-generic/vmlinux.lds.h defines VMLINUX_SYMBOL(sym)
3) include/linux/export.h defines MODULE_SYMBOL_PREFIX.
4) include/linux/kernel.h defines SYMBOL_PREFIX (which differs from #7)
5) kernel/modsign_certificate.S defines ASM_SYMBOL(sym)
6) scripts/modpost.c defines MODULE_SYMBOL_PREFIX
7) scripts/Makefile.lib defines SYMBOL_PREFIX on the commandline if
CONFIG_SYMBOL_PREFIX is set, so that we have a non-string version
for pasting.
(arch/h8300/include/asm/linkage.h defines SYMBOL_NAME(), too).
Let's solve this properly:
1) No more generic prefix, just CONFIG_HAVE_UNDERSCORE_SYMBOL_PREFIX.
2) Make linux/export.h usable from asm.
3) Define VMLINUX_SYMBOL() and VMLINUX_SYMBOL_STR().
4) Make everyone use them.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Reviewed-by: James Hogan <james.hogan@imgtec.com>
Tested-by: James Hogan <james.hogan@imgtec.com> (metag)
The shell '.' command is not required to search the current directory as
a fallback and in fact newer versions of bash in sh-mode do not do this.
Force reading the file from the current directory if $KCONFIG_CONFIG
contains no '/'.
Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Michal Marek <mmarek@suse.cz>
Its possible to superseed the config file with KCONFIG_CONFIG and have
completely no .config in the tree. The current script is sourcing
.config in every case, so the kernel will never build succesfully. This
patch fixes that issue by sourcing KCONFIG_CONFIG instead.
Signed-off-by: Michael Grzeschik <m.grzeschik@pengutronix.de>
Signed-off-by: Michal Marek <mmarek@suse.cz>
Michael Grzeschikauthored and Michal Marekcommited 2013-02-22 10:37:18 +01:00
Pull blackfin updates from Bob Liu:
"One kbuild and a smp build fix."
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/lliubbo/blackfin:
kbuild: add symbol prefix arg to kallsyms
blackfin: smp: adapt to generic smp helpers
Commit 1f2bfbd00e ("kbuild: link of
vmlinux moved to a script") introduced in v3.5-rc1 broke kallsyms on
architectures which have symbol prefixes.
The --symbol-prefix argument used to be added to the KALLSYMS command
line from the architecture Makefile, however this isn't picked up by the
new scripts/link-vmlinux.sh. This resulted in symbols like
kallsyms_addresses being added which weren't correctly overriding the
weak symbols such as _kallsyms_addresses. These could then trigger
BUG_ONs in kallsyms code.
This is fixed by removing the KALLSYMS addition from the architecture
Makefile, and using CONFIG_SYMBOL_PREFIX in the link-vmlinux.sh script
to determine whether to add the --symbol-prefix argument.
Signed-off-by: James Hogan <james.hogan@imgtec.com>
Signed-off-by: Bob Liu <lliubbo@gmail.com>
James Hoganauthored and Bob Liucommited 2012-09-11 10:25:12 +08:00
... at least in the top-level Makefile and scripts/link-vmlinux.sh.
There are some more instances of the 'echo <error>; exit 1' pattern in
some arch Makefiles and kconfig.
Reported-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Michal Marek <mmarek@suse.cz>
Pull kbuild updates from Michal Marek.
Fixed up nontrivial merge conflict in Makefile as per Stephen Rothwell
and linux-next (and trivial arch/sparc/Makefile changes due to removed
sparc32 logic).
* 'kbuild' of git://git.kernel.org/pub/scm/linux/kernel/git/mmarek/kbuild:
mips: Fix KBUILD_CPPFLAGS definition
kbuild: fix ia64 link
kbuild: document KBUILD_LDS, KBUILD_VMLINUX_{INIT,MAIN} and LDFLAGS_vmlinux
kbuild: link of vmlinux moved to a script
kbuild: refactor final link of sparc32
kbuild: drop unused KBUILD_VMLINUX_OBJS from top-level Makefile
kbuild: Makefile: remove unnecessary check for m68knommu ARCH
ia64 build failed like this:
CC init/version.o
LD init/built-in.o
KSYM .tmp_kallsyms1.o
ld: .tmp_kallsyms1.o: linking constant-gp files with non-constant-gp files
ld: failed to merge target specific data of file .tmp_kallsyms1.o
make: *** [vmlinux] Error 1
This was introduced when link of vmlinux was migrated to a script.
Add missing option to as to fix this.
Reported-by: Tony Luck <tony.luck@gmail.com>
Tested-by: Tony Luck <tony.luck@gmail.com>
Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
Signed-off-by: Michal Marek <mmarek@suse.cz>
Sam Ravnborgauthored and Michal Marekcommited 2012-05-10 14:09:21 +02:00
Move the final link of vmlinux to a script to improve
readability and maintainability of the code.
The Makefile fragments used to link vmlinux has over the
years seen far too many changes and the logic had become
hard to follow.
As the process by nature is serialized there was
nothing gained including this in the Makefile.
"um" has special link requirments - and the
only way to handle this was to hard-code the linking
of "um" in the script.
This was better than trying to modularize it only for the
benefit of "um" anyway.
The shell script has been improved after input from:
Arnaud Lacombe <lacombar@gmail.com>
Nick Bowler <nbowler@elliptictech.com>
Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
Cc: Arnaud Lacombe <lacombar@gmail.com>
Cc: Nick Bowler <nbowler@elliptictech.com>
Cc: Richard Weinberger <richard@nod.at>
Signed-off-by: Michal Marek <mmarek@suse.cz>
Sam Ravnborgauthored and Michal Marekcommited 2012-05-05 21:19:33 +02:00
Fangrui Song
authored and
Sorayukii
commited 
Andrii Nakryiko
authored and
vutung2311
authored and
Preeti Nagar
commited 
Blagovest Kolenichev
commited 
Sami Tolvanen
commited 
Arun Menon
commited 
Stephen Rothwell
authored and
Michal Marek
commited 
Emese Revfy
authored and
Ard Biesheuvel
authored and
Russell King
commited 
Linus Torvalds
commited 
Vegard Nossum
authored and
Richard Weinberger
commited 
Lorenzo Colitti
authored and
Maxime Coquelin
authored and
Michal Marek
commited 
Sylvain BERTRAND
authored and
Rusty Russell
commited 
Ming Lei
authored and
Michael Grzeschik
authored and
James Hogan
authored and
Bob Liu
commited 
Sam Ravnborg
authored and