a27249e80348f4be1b94de0e2189ffeecf879392
142
Commits
| Author | SHA1 | Message | Date | |
|---|---|---|---|---|
 Borislav Petkov
|
60753dc829 |
x86: Fix early boot crash on gcc-10, third try
commit
|
||
|
Vegard Nossum
|
b3ee5ef07e |
compiler.h: fix error in BUILD_BUG_ON() reporting
[ Upstream commit
|
||
|
Andrey Ryabinin
|
8ac9e068f8 |
compiler.h: Add read_word_at_a_time() function.
[ Upstream commit
|
||
|
Andrey Ryabinin
|
21b1e01dea |
compiler.h, kasan: Avoid duplicating __read_once_size_nocheck()
[ Upstream commit
|
||
|
Sasha Levin
|
c6975e4196 |
Revert "compiler.h: update definition of unreachable()"
This reverts commit |
||
|
ndesaulniers@google.com
|
82017e26e5 |
compiler.h: update definition of unreachable()
[ Upstream commit |
||
|
Mikulas Patocka
|
26e03f8dcd |
branch-check: fix long->int truncation when profiling branches
commit |
||
|
Arnd Bergmann
|
305eb32d45 |
bug.h: work around GCC PR82365 in BUG()
[ Upstream commit
|
||
|
Geert Uytterhoeven
|
045e5161ab |
compiler-gcc.h: Introduce __optimize function attribute
commit
|
||
|
Will Deacon
|
a9772285a7 |
linux/compiler.h: Split into compiler.h and compiler_types.h
commit
|
||
|
Will Deacon
|
1aedecaf12 |
locking/barriers: Add implicit smp_read_barrier_depends() to READ_ONCE()
commit |
||
|
Josh Poimboeuf
|
ec1e1b6109 |
objtool: Prevent GCC from merging annotate_unreachable(), take 2
This fixes the following warning with GCC 4.6: mm/migrate.o: warning: objtool: migrate_misplaced_transhuge_page()+0x71: unreachable instruction The problem is that the compiler merged identical annotate_unreachable() inline asm blocks, resulting in a missing 'unreachable' annotation. This problem happened before, and was partially fixed with: |
||
|
Greg Kroah-Hartman
|
b24413180f |
License cleanup: add SPDX GPL-2.0 license identifier to files with no license
Many source files in the tree are missing licensing information, which makes it harder for compliance tools to determine the correct license. By default all files without license information are under the default license of the kernel, which is GPL version 2. Update the files which contain no license information with the 'GPL-2.0' SPDX license identifier. The SPDX identifier is a legally binding shorthand, which can be used instead of the full boiler plate text. This patch is based on work done by Thomas Gleixner and Kate Stewart and Philippe Ombredanne. How this work was done: Patches were generated and checked against linux-4.14-rc6 for a subset of the use cases: - file had no licensing information it it. - file was a */uapi/* one with no licensing information in it, - file was a */uapi/* one with existing licensing information, Further patches will be generated in subsequent months to fix up cases where non-standard license headers were used, and references to license had to be inferred by heuristics based on keywords. The analysis to determine which SPDX License Identifier to be applied to a file was done in a spreadsheet of side by side results from of the output of two independent scanners (ScanCode & Windriver) producing SPDX tag:value files created by Philippe Ombredanne. Philippe prepared the base worksheet, and did an initial spot review of a few 1000 files. The 4.13 kernel was the starting point of the analysis with 60,537 files assessed. Kate Stewart did a file by file comparison of the scanner results in the spreadsheet to determine which SPDX license identifier(s) to be applied to the file. She confirmed any determination that was not immediately clear with lawyers working with the Linux Foundation. Criteria used to select files for SPDX license identifier tagging was: - Files considered eligible had to be source code files. - Make and config files were included as candidates if they contained >5 lines of source - File already had some variant of a license header in it (even if <5 lines). All documentation files were explicitly excluded. The following heuristics were used to determine which SPDX license identifiers to apply. - when both scanners couldn't find any license traces, file was considered to have no license information in it, and the top level COPYING file license applied. For non */uapi/* files that summary was: SPDX license identifier # files ---------------------------------------------------|------- GPL-2.0 11139 and resulted in the first patch in this series. If that file was a */uapi/* path one, it was "GPL-2.0 WITH Linux-syscall-note" otherwise it was "GPL-2.0". Results of that was: SPDX license identifier # files ---------------------------------------------------|------- GPL-2.0 WITH Linux-syscall-note 930 and resulted in the second patch in this series. - if a file had some form of licensing information in it, and was one of the */uapi/* ones, it was denoted with the Linux-syscall-note if any GPL family license was found in the file or had no licensing in it (per prior point). Results summary: SPDX license identifier # files ---------------------------------------------------|------ GPL-2.0 WITH Linux-syscall-note 270 GPL-2.0+ WITH Linux-syscall-note 169 ((GPL-2.0 WITH Linux-syscall-note) OR BSD-2-Clause) 21 ((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause) 17 LGPL-2.1+ WITH Linux-syscall-note 15 GPL-1.0+ WITH Linux-syscall-note 14 ((GPL-2.0+ WITH Linux-syscall-note) OR BSD-3-Clause) 5 LGPL-2.0+ WITH Linux-syscall-note 4 LGPL-2.1 WITH Linux-syscall-note 3 ((GPL-2.0 WITH Linux-syscall-note) OR MIT) 3 ((GPL-2.0 WITH Linux-syscall-note) AND MIT) 1 and that resulted in the third patch in this series. - when the two scanners agreed on the detected license(s), that became the concluded license(s). - when there was disagreement between the two scanners (one detected a license but the other didn't, or they both detected different licenses) a manual inspection of the file occurred. - In most cases a manual inspection of the information in the file resulted in a clear resolution of the license that should apply (and which scanner probably needed to revisit its heuristics). - When it was not immediately clear, the license identifier was confirmed with lawyers working with the Linux Foundation. - If there was any question as to the appropriate license identifier, the file was flagged for further research and to be revisited later in time. In total, over 70 hours of logged manual review was done on the spreadsheet to determine the SPDX license identifiers to apply to the source files by Kate, Philippe, Thomas and, in some cases, confirmation by lawyers working with the Linux Foundation. Kate also obtained a third independent scan of the 4.13 code base from FOSSology, and compared selected files where the other two scanners disagreed against that SPDX file, to see if there was new insights. The Windriver scanner is based on an older version of FOSSology in part, so they are related. Thomas did random spot checks in about 500 files from the spreadsheets for the uapi headers and agreed with SPDX license identifier in the files he inspected. For the non-uapi files Thomas did random spot checks in about 15000 files. In initial set of patches against 4.14-rc6, 3 files were found to have copy/paste license identifier errors, and have been fixed to reflect the correct identifier. Additionally Philippe spent 10 hours this week doing a detailed manual inspection and review of the 12,461 patched files from the initial patch version early this week with: - a full scancode scan run, collecting the matched texts, detected license ids and scores - reviewing anything where there was a license detected (about 500+ files) to ensure that the applied SPDX license was correct - reviewing anything where there was no detection but the patch license was not GPL-2.0 WITH Linux-syscall-note to ensure that the applied SPDX license was correct This produced a worksheet with 20 files needing minor correction. This worksheet was then exported into 3 different .csv files for the different types of files to be modified. These .csv files were then reviewed by Greg. Thomas wrote a script to parse the csv files and add the proper SPDX tag to the file, in the format that the file expected. This script was further refined by Greg based on the output to detect more types of files automatically and to distinguish between header and source .c files (which need different comment types.) Finally Greg ran the script using the .csv files to generate the patches. Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org> Reviewed-by: Philippe Ombredanne <pombredanne@nexb.com> Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
||
|
Linus Torvalds
|
b1b6f83ac9 |
Merge branch 'x86-mm-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 mm changes from Ingo Molnar:
"PCID support, 5-level paging support, Secure Memory Encryption support
The main changes in this cycle are support for three new, complex
hardware features of x86 CPUs:
- Add 5-level paging support, which is a new hardware feature on
upcoming Intel CPUs allowing up to 128 PB of virtual address space
and 4 PB of physical RAM space - a 512-fold increase over the old
limits. (Supercomputers of the future forecasting hurricanes on an
ever warming planet can certainly make good use of more RAM.)
Many of the necessary changes went upstream in previous cycles,
v4.14 is the first kernel that can enable 5-level paging.
This feature is activated via CONFIG_X86_5LEVEL=y - disabled by
default.
(By Kirill A. Shutemov)
- Add 'encrypted memory' support, which is a new hardware feature on
upcoming AMD CPUs ('Secure Memory Encryption', SME) allowing system
RAM to be encrypted and decrypted (mostly) transparently by the
CPU, with a little help from the kernel to transition to/from
encrypted RAM. Such RAM should be more secure against various
attacks like RAM access via the memory bus and should make the
radio signature of memory bus traffic harder to intercept (and
decrypt) as well.
This feature is activated via CONFIG_AMD_MEM_ENCRYPT=y - disabled
by default.
(By Tom Lendacky)
- Enable PCID optimized TLB flushing on newer Intel CPUs: PCID is a
hardware feature that attaches an address space tag to TLB entries
and thus allows to skip TLB flushing in many cases, even if we
switch mm's.
(By Andy Lutomirski)
All three of these features were in the works for a long time, and
it's coincidence of the three independent development paths that they
are all enabled in v4.14 at once"
* 'x86-mm-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (65 commits)
x86/mm: Enable RCU based page table freeing (CONFIG_HAVE_RCU_TABLE_FREE=y)
x86/mm: Use pr_cont() in dump_pagetable()
x86/mm: Fix SME encryption stack ptr handling
kvm/x86: Avoid clearing the C-bit in rsvd_bits()
x86/CPU: Align CR3 defines
x86/mm, mm/hwpoison: Clear PRESENT bit for kernel 1:1 mappings of poison pages
acpi, x86/mm: Remove encryption mask from ACPI page protection type
x86/mm, kexec: Fix memory corruption with SME on successive kexecs
x86/mm/pkeys: Fix typo in Documentation/x86/protection-keys.txt
x86/mm/dump_pagetables: Speed up page tables dump for CONFIG_KASAN=y
x86/mm: Implement PCID based optimization: try to preserve old TLB entries using PCID
x86: Enable 5-level paging support via CONFIG_X86_5LEVEL=y
x86/mm: Allow userspace have mappings above 47-bit
x86/mm: Prepare to expose larger address space to userspace
x86/mpx: Do not allow MPX if we have mappings above 47-bit
x86/mm: Rename tasksize_32bit/64bit to task_size_32bit/64bit()
x86/xen: Redefine XEN_ELFNOTE_INIT_P2M using PUD_SIZE * PTRS_PER_PUD
x86/mm/dump_pagetables: Fix printout of p4d level
x86/mm/dump_pagetables: Generalize address normalization
x86/boot: Fix memremap() related build failure
...
|
||
|
Linus Torvalds
|
b0c79f49c3 |
Merge branch 'x86-asm-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 asm updates from Ingo Molnar: - Introduce the ORC unwinder, which can be enabled via CONFIG_ORC_UNWINDER=y. The ORC unwinder is a lightweight, Linux kernel specific debuginfo implementation, which aims to be DWARF done right for unwinding. Objtool is used to generate the ORC unwinder tables during build, so the data format is flexible and kernel internal: there's no dependency on debuginfo created by an external toolchain. The ORC unwinder is almost two orders of magnitude faster than the (out of tree) DWARF unwinder - which is important for perf call graph profiling. It is also significantly simpler and is coded defensively: there has not been a single ORC related kernel crash so far, even with early versions. (knock on wood!) But the main advantage is that enabling the ORC unwinder allows CONFIG_FRAME_POINTERS to be turned off - which speeds up the kernel measurably: With frame pointers disabled, GCC does not have to add frame pointer instrumentation code to every function in the kernel. The kernel's .text size decreases by about 3.2%, resulting in better cache utilization and fewer instructions executed, resulting in a broad kernel-wide speedup. Average speedup of system calls should be roughly in the 1-3% range - measurements by Mel Gorman [1] have shown a speedup of 5-10% for some function execution intense workloads. The main cost of the unwinder is that the unwinder data has to be stored in RAM: the memory cost is 2-4MB of RAM, depending on kernel config - which is a modest cost on modern x86 systems. Given how young the ORC unwinder code is it's not enabled by default - but given the performance advantages the plan is to eventually make it the default unwinder on x86. See Documentation/x86/orc-unwinder.txt for more details. - Remove lguest support: its intended role was that of a temporary proof of concept for virtualization, plus its removal will enable the reduction (removal) of the paravirt API as well, so Rusty agreed to its removal. (Juergen Gross) - Clean up and fix FSGS related functionality (Andy Lutomirski) - Clean up IO access APIs (Andy Shevchenko) - Enhance the symbol namespace (Jiri Slaby) * 'x86-asm-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (47 commits) objtool: Handle GCC stack pointer adjustment bug x86/entry/64: Use ENTRY() instead of ALIGN+GLOBAL for stub32_clone() x86/fpu/math-emu: Add ENDPROC to functions x86/boot/64: Extract efi_pe_entry() from startup_64() x86/boot/32: Extract efi_pe_entry() from startup_32() x86/lguest: Remove lguest support x86/paravirt/xen: Remove xen_patch() objtool: Fix objtool fallthrough detection with function padding x86/xen/64: Fix the reported SS and CS in SYSCALL objtool: Track DRAP separately from callee-saved registers objtool: Fix validate_branch() return codes x86: Clarify/fix no-op barriers for text_poke_bp() x86/switch_to/64: Rewrite FS/GS switching yet again to fix AMD CPUs selftests/x86/fsgsbase: Test selectors 1, 2, and 3 x86/fsgsbase/64: Report FSBASE and GSBASE correctly in core dumps x86/fsgsbase/64: Fully initialize FS and GS state in start_thread_common x86/asm: Fix UNWIND_HINT_REGS macro for older binutils x86/asm/32: Fix regs_get_register() on segment registers x86/xen/64: Rearrange the SYSCALL entries x86/asm/32: Remove a bunch of '& 0xffff' from pt_regs segment reads ... |
||
|
Joe Stringer
|
c03567a8e8 |
include/linux/compiler.h: don't perform compiletime_assert with -O0
Commit |
||
|
Ingo Molnar
|
413d63d71b |
Merge branch 'linus' into x86/mm to pick up fixes and to fix conflicts
Conflicts: arch/x86/kernel/head64.c arch/x86/mm/mmap.c Signed-off-by: Ingo Molnar <mingo@kernel.org> |
||
|
Ingo Molnar
|
1d0f49e140 |
Merge branch 'x86/urgent' into x86/asm, to pick up fixes
Signed-off-by: Ingo Molnar <mingo@kernel.org> |
||
|
Josh Poimboeuf
|
649ea4d5a6 |
objtool: Assume unannotated UD2 instructions are dead ends
Arnd reported some false positive warnings with GCC 7: drivers/hid/wacom_wac.o: warning: objtool: wacom_bpt3_touch()+0x2a5: stack state mismatch: cfa1=7+8 cfa2=6+16 drivers/iio/adc/vf610_adc.o: warning: objtool: vf610_adc_calculate_rates() falls through to next function vf610_adc_sample_set() drivers/pwm/pwm-hibvt.o: warning: objtool: hibvt_pwm_get_state() falls through to next function hibvt_pwm_remove() drivers/pwm/pwm-mediatek.o: warning: objtool: mtk_pwm_config() falls through to next function mtk_pwm_enable() drivers/spi/spi-bcm2835.o: warning: objtool: .text: unexpected end of section drivers/spi/spi-bcm2835aux.o: warning: objtool: .text: unexpected end of section drivers/watchdog/digicolor_wdt.o: warning: objtool: dc_wdt_get_timeleft() falls through to next function dc_wdt_restart() When GCC 7 detects a potential divide-by-zero condition, it sometimes inserts a UD2 instruction for the case where the divisor is zero, instead of letting the hardware trap on the divide instruction. Objtool doesn't consider UD2 to be fatal unless it's annotated with unreachable(). So it considers the GCC-generated UD2 to be non-fatal, and it tries to follow the control flow past the UD2 and gets confused. Previously, objtool *did* assume UD2 was always a dead end. That changed with the following commit: |
||
|
Kees Cook
|
aa5d1b8150 |
x86/asm: Add ASM_UNREACHABLE
This creates an unreachable annotation in asm for CONFIG_STACK_VALIDATION=y. While here, adjust earlier uses of \t\n into \n\t. Suggested-by: Josh Poimboeuf <jpoimboe@redhat.com> Signed-off-by: Kees Cook <keescook@chromium.org> Cc: Alexey Dobriyan <adobriyan@gmail.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Christoph Hellwig <hch@infradead.org> Cc: David S. Miller <davem@davemloft.net> Cc: Davidlohr Bueso <dave@stgolabs.net> Cc: Elena Reshetova <elena.reshetova@intel.com> Cc: Eric Biggers <ebiggers3@gmail.com> Cc: Eric W. Biederman <ebiederm@xmission.com> Cc: Greg KH <gregkh@linuxfoundation.org> Cc: Hans Liljestrand <ishkamiel@gmail.com> Cc: James Bottomley <James.Bottomley@hansenpartnership.com> Cc: Jann Horn <jannh@google.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Manfred Spraul <manfred@colorfullife.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Rik van Riel <riel@redhat.com> Cc: Serge E. Hallyn <serge@hallyn.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: arozansk@redhat.com Cc: axboe@kernel.dk Cc: kernel-hardening@lists.openwall.com Cc: linux-arch <linux-arch@vger.kernel.org> Link: http://lkml.kernel.org/r/1500921349-10803-3-git-send-email-keescook@chromium.org Signed-off-by: Ingo Molnar <mingo@kernel.org> |
||
|
Linus Torvalds
|
e06fdaf40a |
Merge tag 'gcc-plugins-v4.13-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux
Pull structure randomization updates from Kees Cook:
"Now that IPC and other changes have landed, enable manual markings for
randstruct plugin, including the task_struct.
This is the rest of what was staged in -next for the gcc-plugins, and
comes in three patches, largest first:
- mark "easy" structs with __randomize_layout
- mark task_struct with an optional anonymous struct to isolate the
__randomize_layout section
- mark structs to opt _out_ of automated marking (which will come
later)
And, FWIW, this continues to pass allmodconfig (normal and patched to
enable gcc-plugins) builds of x86_64, i386, arm64, arm, powerpc, and
s390 for me"
* tag 'gcc-plugins-v4.13-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux:
randstruct: opt-out externally exposed function pointer structs
task_struct: Allow randomized layout
randstruct: Mark various structs for randomization
|
||
|
Tom Lendacky
|
7375ae3a0b |
compiler-gcc.h: Introduce __nostackprotector function attribute
Create a new function attribute, __nostackprotector, that can used to turn off stack protection on a per function basis. Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com> Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Cc: Alexander Potapenko <glider@google.com> Cc: Andrey Ryabinin <aryabinin@virtuozzo.com> Cc: Andy Lutomirski <luto@kernel.org> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Borislav Petkov <bp@alien8.de> Cc: Brijesh Singh <brijesh.singh@amd.com> Cc: Dave Young <dyoung@redhat.com> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Cc: Larry Woodman <lwoodman@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Matt Fleming <matt@codeblueprint.co.uk> Cc: Michael S. Tsirkin <mst@redhat.com> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Radim Krčmář <rkrcmar@redhat.com> Cc: Rik van Riel <riel@redhat.com> Cc: Toshimitsu Kani <toshi.kani@hpe.com> Cc: kasan-dev@googlegroups.com Cc: kvm@vger.kernel.org Cc: linux-arch@vger.kernel.org Cc: linux-doc@vger.kernel.org Cc: linux-efi@vger.kernel.org Cc: linux-mm@kvack.org Link: http://lkml.kernel.org/r/0576fd5c74440ad0250f16ac6609ecf587812456.1500319216.git.thomas.lendacky@amd.com Signed-off-by: Ingo Molnar <mingo@kernel.org> |
||
|
Linus Torvalds
|
59005b0c59 |
Merge tag 'gcc-plugins-v4.13-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux
Pull GCC plugin updates from Kees Cook: "The big part is the randstruct plugin infrastructure. This is the first of two expected pull requests for randstruct since there are dependencies in other trees that would be easier to merge once those have landed. Notably, the IPC allocation refactoring in -mm, and many trivial merge conflicts across several trees when applying the __randomize_layout annotation. As a result, it seemed like I should send this now since it is relatively self-contained, and once the rest of the trees have landed, send the annotation patches. I'm expecting the final phase of randstruct (automatic struct selection) will land for v4.14, but if its other tree dependencies actually make it for v4.13, I can send that merge request too. Summary: - typo fix in Kconfig (Jean Delvare) - randstruct infrastructure" * tag 'gcc-plugins-v4.13-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux: ARM: Prepare for randomized task_struct randstruct: Whitelist NIU struct page overloading randstruct: Whitelist big_key path struct overloading randstruct: Whitelist UNIXCB cast randstruct: Whitelist struct security_hook_heads cast gcc-plugins: Add the randstruct plugin Fix English in description of GCC_PLUGIN_STRUCTLEAK compiler: Add __designated_init annotation gcc-plugins: Detail c-common.h location for GCC 4.6 |
||
|
Kees Cook
|
29e48ce87f |
task_struct: Allow randomized layout
This marks most of the layout of task_struct as randomizable, but leaves thread_info and scheduler state untouched at the start, and thread_struct untouched at the end. Other parts of the kernel use unnamed structures, but the 0-day builder using gcc-4.4 blows up on static initializers. Officially, it's documented as only working on gcc 4.6 and later, which further confuses me: https://gcc.gnu.org/wiki/C11Status The structure layout randomization already requires gcc 4.7, but instead of depending on the plugin being enabled, just check the gcc versions for wider build testing. At Linus's suggestion, the marking is hidden in a macro to reduce how ugly it looks. Additionally, indenting is left unchanged since it would make things harder to read. Randomization of task_struct is modified from Brad Spengler/PaX Team's code in the last public patch of grsecurity/PaX based on my understanding of the code. Changes or omissions from the original code are mine and don't reflect the original grsecurity/PaX code. Cc: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Kees Cook <keescook@chromium.org> |
||
|
Kees Cook
|
313dd1b629 |
gcc-plugins: Add the randstruct plugin
This randstruct plugin is modified from Brad Spengler/PaX Team's code in the last public patch of grsecurity/PaX based on my understanding of the code. Changes or omissions from the original code are mine and don't reflect the original grsecurity/PaX code. The randstruct GCC plugin randomizes the layout of selected structures at compile time, as a probabilistic defense against attacks that need to know the layout of structures within the kernel. This is most useful for "in-house" kernel builds where neither the randomization seed nor other build artifacts are made available to an attacker. While less useful for distribution kernels (where the randomization seed must be exposed for third party kernel module builds), it still has some value there since now all kernel builds would need to be tracked by an attacker. In more performance sensitive scenarios, GCC_PLUGIN_RANDSTRUCT_PERFORMANCE can be selected to make a best effort to restrict randomization to cacheline-sized groups of elements, and will not randomize bitfields. This comes at the cost of reduced randomization. Two annotations are defined,__randomize_layout and __no_randomize_layout, which respectively tell the plugin to either randomize or not to randomize instances of the struct in question. Follow-on patches enable the auto-detection logic for selecting structures for randomization that contain only function pointers. It is disabled here to assist with bisection. Since any randomized structs must be initialized using designated initializers, __randomize_layout includes the __designated_init annotation even when the plugin is disabled so that all builds will require the needed initialization. (With the plugin enabled, annotations for automatically chosen structures are marked as well.) The main differences between this implemenation and grsecurity are: - disable automatic struct selection (to be enabled in follow-up patch) - add designated_init attribute at runtime and for manual marking - clarify debugging output to differentiate bad cast warnings - add whitelisting infrastructure - support gcc 7's DECL_ALIGN and DECL_MODE changes (Laura Abbott) - raise minimum required GCC version to 4.7 Earlier versions of this patch series were ported by Michael Leibowitz. Signed-off-by: Kees Cook <keescook@chromium.org> |
||
|
Paul E. McKenney
|
41a2901e7d |
rcu: Remove SPARSE_RCU_POINTER Kconfig option
The sparse-based checking for non-RCU accesses to RCU-protected pointers has been around for a very long time, and it is now the only type of sparse-based checking that is optional. This commit therefore makes it unconditional. Reported-by: Ingo Molnar <mingo@kernel.org> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Fengguang Wu <fengguang.wu@intel.com> |
||
|
Kees Cook
|
0aa5e49c68 |
compiler: Add __designated_init annotation
This allows structure annotations for requiring designated initialization in GCC 5.1.0 and later: https://gcc.gnu.org/onlinedocs/gcc/Designated-Inits.html The structure randomization layout plugin will be using this to help identify structures that need this form of initialization. Signed-off-by: Kees Cook <keescook@chromium.org> |
||
|
Linus Torvalds
|
86292b33d4 |
Merge branch 'akpm' (patches from Andrew)
Merge yet more updates from Andrew Morton: - a few MM remainders - misc things - autofs updates - signals - affs updates - ipc - nilfs2 - spelling.txt updates * emailed patches from Andrew Morton <akpm@linux-foundation.org>: (78 commits) mm, x86: fix HIGHMEM64 && PARAVIRT build config for native_pud_clear() mm: add arch-independent testcases for RODATA hfs: atomically read inode size mm: clarify mm_struct.mm_{users,count} documentation mm: use mmget_not_zero() helper mm: add new mmget() helper mm: add new mmgrab() helper checkpatch: warn when formats use %Z and suggest %z lib/vsprintf.c: remove %Z support scripts/spelling.txt: add some typo-words scripts/spelling.txt: add "followings" pattern and fix typo instances scripts/spelling.txt: add "therfore" pattern and fix typo instances scripts/spelling.txt: add "overwriten" pattern and fix typo instances scripts/spelling.txt: add "overwritting" pattern and fix typo instances scripts/spelling.txt: add "deintialize(d)" pattern and fix typo instances scripts/spelling.txt: add "disassocation" pattern and fix typo instances scripts/spelling.txt: add "omited" pattern and fix typo instances scripts/spelling.txt: add "explictely" pattern and fix typo instances scripts/spelling.txt: add "applys" pattern and fix typo instances scripts/spelling.txt: add "configuartion" pattern and fix typo instances ... |
||
|
Luis R. Rodriguez
|
7d134b2ce6 |
kprobes: move kprobe declarations to asm-generic/kprobes.h
Often all is needed is these small helpers, instead of compiler.h or a full kprobes.h. This is important for asm helpers, in fact even some asm/kprobes.h make use of these helpers... instead just keep a generic asm file with helpers useful for asm code with the least amount of clutter as possible. Likewise we need now to also address what to do about this file for both when architectures have CONFIG_HAVE_KPROBES, and when they do not. Then for when architectures have CONFIG_HAVE_KPROBES but have disabled CONFIG_KPROBES. Right now most asm/kprobes.h do not have guards against CONFIG_KPROBES, this means most architecture code cannot include asm/kprobes.h safely. Correct this and add guards for architectures missing them. Additionally provide architectures that not have kprobes support with the default asm-generic solution. This lets us force asm/kprobes.h on the header include/linux/kprobes.h always, but most importantly we can now safely include just asm/kprobes.h on architecture code without bringing the full kitchen sink of header files. Two architectures already provided a guard against CONFIG_KPROBES on its kprobes.h: sh, arch. The rest of the architectures needed gaurds added. We avoid including any not-needed headers on asm/kprobes.h unless kprobes have been enabled. In a subsequent atomic change we can try now to remove compiler.h from include/linux/kprobes.h. During this sweep I've also identified a few architectures defining a common macro needed for both kprobes and ftrace, that of the definition of the breakput instruction up. Some refer to this as BREAKPOINT_INSTRUCTION. This must be kept outside of the #ifdef CONFIG_KPROBES guard. [mcgrof@kernel.org: fix arm64 build] Link: http://lkml.kernel.org/r/CAB=NE6X1WMByuARS4mZ1g9+W=LuVBnMDnh_5zyN0CLADaVh=Jw@mail.gmail.com [sfr@canb.auug.org.au: fixup for kprobes declarations moving] Link: http://lkml.kernel.org/r/20170214165933.13ebd4f4@canb.auug.org.au Link: http://lkml.kernel.org/r/20170203233139.32682-1-mcgrof@kernel.org Signed-off-by: Luis R. Rodriguez <mcgrof@kernel.org> Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au> Acked-by: Masami Hiramatsu <mhiramat@kernel.org> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Ananth N Mavinakayanahalli <ananth@linux.vnet.ibm.com> Cc: Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com> Cc: David S. Miller <davem@davemloft.net> Cc: Ingo Molnar <mingo@kernel.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Andy Lutomirski <luto@kernel.org> Cc: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
||
|
Linus Torvalds
|
79b17ea740 |
Merge tag 'trace-v4.11' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace
Pull tracing updates from Steven Rostedt:
"This release has no new tracing features, just clean ups, minor fixes
and small optimizations"
* tag 'trace-v4.11' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace: (25 commits)
tracing: Remove outdated ring buffer comment
tracing/probes: Fix a warning message to show correct maximum length
tracing: Fix return value check in trace_benchmark_reg()
tracing: Use modern function declaration
jump_label: Reduce the size of struct static_key
tracing/probe: Show subsystem name in messages
tracing/hwlat: Update old comment about migration
timers: Make flags output in the timer_start tracepoint useful
tracing: Have traceprobe_probes_write() not access userspace unnecessarily
tracing: Have COMM event filter key be treated as a string
ftrace: Have set_graph_function handle multiple functions in one write
ftrace: Do not hold references of ftrace_graph_{notrace_}hash out of graph_lock
tracing: Reset parser->buffer to allow multiple "puts"
ftrace: Have set_graph_functions handle write with RDWR
ftrace: Reset fgd->hash in ftrace_graph_write()
ftrace: Replace (void *)1 with a meaningful macro name FTRACE_GRAPH_EMPTY
ftrace: Create a slight optimization on searching the ftrace_hash
tracing: Add ftrace_hash_key() helper function
ftrace: Convert graph filter to use hash tables
ftrace: Expose ftrace_hash_empty and ftrace_lookup_ip
...
|
||
|
Steven Rostedt (VMware)
|
134e6a034c |
tracing: Show number of constants profiled in likely profiler
Now that constants are traced, it is useful to see the number of constants that are traced in the likely/unlikely profiler in order to know if they should be ignored or not. The likely/unlikely will display a number after the "correct" number if a "constant" count exists. Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org> |
||
|
Kees Cook
|
c61f13eaa1 |
gcc-plugins: Add structleak for more stack initialization
This plugin detects any structures that contain __user attributes and makes sure it is being fully initialized so that a specific class of information exposure is eliminated. (This plugin was originally designed to block the exposure of siginfo in CVE-2013-2141.) Ported from grsecurity/PaX. This version adds a verbose option to the plugin and the Kconfig. Signed-off-by: Kees Cook <keescook@chromium.org> |
||
|
Steven Rostedt (VMware)
|
d45ae1f704 |
tracing: Process constants for (un)likely() profiler
When running the likely/unlikely profiler, one of the results did not look accurate. It noted that the unlikely() in link_path_walk() was 100% incorrect. When I added a trace_printk() to see what was happening there, it became 80% correct! Looking deeper into what whas happening, I found that gcc split that if statement into two paths. One where the if statement became a constant, the other path a variable. The other path had the if statement always hit (making the unlikely there, always false), but since the #define unlikely() has: #define unlikely() (__builtin_constant_p(x) ? !!(x) : __branch_check__(x, 0)) Where constants are ignored by the branch profiler, the "constant" path made by the compiler was ignored, even though it was hit 80% of the time. By just passing the constant value to the __branch_check__() function and tracing it out of line (as always correct, as likely/unlikely isn't a factor for constants), then we get back the accurate readings of branches that were optimized by gcc causing part of the execution to become constant. Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org> |
||
|
Linus Torvalds
|
9ffc66941d |
Merge tag 'gcc-plugins-v4.9-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux
Pull gcc plugins update from Kees Cook: "This adds a new gcc plugin named "latent_entropy". It is designed to extract as much possible uncertainty from a running system at boot time as possible, hoping to capitalize on any possible variation in CPU operation (due to runtime data differences, hardware differences, SMP ordering, thermal timing variation, cache behavior, etc). At the very least, this plugin is a much more comprehensive example for how to manipulate kernel code using the gcc plugin internals" * tag 'gcc-plugins-v4.9-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux: latent_entropy: Mark functions with __latent_entropy gcc-plugins: Add latent_entropy plugin |
||
|
Linus Torvalds
|
84d69848c9 |
Merge branch 'kbuild' of git://git.kernel.org/pub/scm/linux/kernel/git/mmarek/kbuild
Pull kbuild updates from Michal Marek: - EXPORT_SYMBOL for asm source by Al Viro. This does bring a regression, because genksyms no longer generates checksums for these symbols (CONFIG_MODVERSIONS). Nick Piggin is working on a patch to fix this. Plus, we are talking about functions like strcpy(), which rarely change prototypes. - Fixes for PPC fallout of the above by Stephen Rothwell and Nick Piggin - fixdep speedup by Alexey Dobriyan. - preparatory work by Nick Piggin to allow architectures to build with -ffunction-sections, -fdata-sections and --gc-sections - CONFIG_THIN_ARCHIVES support by Stephen Rothwell - fix for filenames with colons in the initramfs source by me. * 'kbuild' of git://git.kernel.org/pub/scm/linux/kernel/git/mmarek/kbuild: (22 commits) initramfs: Escape colons in depfile ppc: there is no clear_pages to export powerpc/64: whitelist unresolved modversions CRCs kbuild: -ffunction-sections fix for archs with conflicting sections kbuild: add arch specific post-link Makefile kbuild: allow archs to select link dead code/data elimination kbuild: allow architectures to use thin archives instead of ld -r kbuild: Regenerate genksyms lexer kbuild: genksyms fix for typeof handling fixdep: faster CONFIG_ search ia64: move exports to definitions sparc32: debride memcpy.S a bit [sparc] unify 32bit and 64bit string.h sparc: move exports to definitions ppc: move exports to definitions arm: move exports to definitions s390: move exports to definitions m68k: move exports to definitions alpha: move exports to actual definitions x86: move exports to actual definitions ... |
||
|
Emese Revfy
|
0766f788eb |
latent_entropy: Mark functions with __latent_entropy
The __latent_entropy gcc attribute can be used only on functions and variables. If it is on a function then the plugin will instrument it for gathering control-flow entropy. If the attribute is on a variable then the plugin will initialize it with random contents. The variable must be an integer, an integer array type or a structure with integer fields. These specific functions have been selected because they are init functions (to help gather boot-time entropy), are called at unpredictable times, or they have variable loops, each of which provide some level of latent entropy. Signed-off-by: Emese Revfy <re.emese@gmail.com> [kees: expanded commit message] Signed-off-by: Kees Cook <keescook@chromium.org> |
||
|
Nicholas Piggin
|
b67067f117 |
kbuild: allow archs to select link dead code/data elimination
Introduce LD_DEAD_CODE_DATA_ELIMINATION option for architectures to
select to build with -ffunction-sections, -fdata-sections, and link
with --gc-sections. It requires some work (documented) to ensure all
unreferenced entrypoints are live, and requires toolchain and build
verification, so it is made a per-arch option for now.
On a random powerpc64le build, this yelds a significant size saving,
it boots and runs fine, but there is a lot I haven't tested as yet, so
these savings may be reduced if there are bugs in the link.
text data bss dec filename
11169741 1180744 1923176 14273661 vmlinux
10445269 1004127 1919707 13369103 vmlinux.dce
~700K text, ~170K data, 6% removed from kernel image size.
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michal Marek <mmarek@suse.com>
|
||
|
Johannes Berg
|
d7127b5e5f |
locking/barriers: Don't use sizeof(void) in lockless_dereference()
My previous commit: |
||
|
Johannes Berg
|
112dc0c806 |
locking/barriers: Suppress sparse warnings in lockless_dereference()
After Peter's commit: |
||
|
Linus Torvalds
|
f0c98ebc57 |
Merge tag 'libnvdimm-for-4.8' of git://git.kernel.org/pub/scm/linux/kernel/git/nvdimm/nvdimm
Pull libnvdimm updates from Dan Williams:
- Replace pcommit with ADR / directed-flushing.
The pcommit instruction, which has not shipped on any product, is
deprecated. Instead, the requirement is that platforms implement
either ADR, or provide one or more flush addresses per nvdimm.
ADR (Asynchronous DRAM Refresh) flushes data in posted write buffers
to the memory controller on a power-fail event.
Flush addresses are defined in ACPI 6.x as an NVDIMM Firmware
Interface Table (NFIT) sub-structure: "Flush Hint Address Structure".
A flush hint is an mmio address that when written and fenced assures
that all previous posted writes targeting a given dimm have been
flushed to media.
- On-demand ARS (address range scrub).
Linux uses the results of the ACPI ARS commands to track bad blocks
in pmem devices. When latent errors are detected we re-scrub the
media to refresh the bad block list, userspace can also request a
re-scrub at any time.
- Support for the Microsoft DSM (device specific method) command
format.
- Support for EDK2/OVMF virtual disk device memory ranges.
- Various fixes and cleanups across the subsystem.
* tag 'libnvdimm-for-4.8' of git://git.kernel.org/pub/scm/linux/kernel/git/nvdimm/nvdimm: (41 commits)
libnvdimm-btt: Delete an unnecessary check before the function call "__nd_device_register"
nfit: do an ARS scrub on hitting a latent media error
nfit: move to nfit/ sub-directory
nfit, libnvdimm: allow an ARS scrub to be triggered on demand
libnvdimm: register nvdimm_bus devices with an nd_bus driver
pmem: clarify a debug print in pmem_clear_poison
x86/insn: remove pcommit
Revert "KVM: x86: add pcommit support"
nfit, tools/testing/nvdimm/: unify shutdown paths
libnvdimm: move ->module to struct nvdimm_bus_descriptor
nfit: cleanup acpi_nfit_init calling convention
nfit: fix _FIT evaluation memory leak + use after free
tools/testing/nvdimm: add manufacturing_{date|location} dimm properties
tools/testing/nvdimm: add virtual ramdisk range
acpi, nfit: treat virtual ramdisk SPA as pmem region
pmem: kill __pmem address space
pmem: kill wmb_pmem()
libnvdimm, pmem: use nvdimm_flush() for namespace I/O writes
fs/dax: remove wmb_pmem()
libnvdimm, pmem: flush posted-write queues on shutdown
...
|
||
|
Dan Williams
|
7a9eb20666 |
pmem: kill __pmem address space
The __pmem address space was meant to annotate codepaths that touch persistent memory and need to coordinate a call to wmb_pmem(). Now that wmb_pmem() is gone, there is little need to keep this annotation. Cc: Christoph Hellwig <hch@lst.de> Cc: Ross Zwisler <ross.zwisler@linux.intel.com> Signed-off-by: Dan Williams <dan.j.williams@intel.com> |
||
|
Peter Zijlstra
|
7cb45c0fe9 |
locking/barriers: Move smp_cond_load_acquire() to asm-generic/barrier.h
Since all asm/barrier.h should/must include asm-generic/barrier.h the latter is a good place for generic infrastructure like this. This also allows archs to override the new smp_acquire__after_ctrl_dep(). Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Ingo Molnar <mingo@kernel.org> |
||
|
Peter Zijlstra
|
33ac279677 |
locking/barriers: Introduce smp_acquire__after_ctrl_dep()
Introduce smp_acquire__after_ctrl_dep(), this construct is not uncommon, but the lack of this barrier is. Use it to better express smp_rmb() uses in WRITE_ONCE(), the IPC semaphore code and the qspinlock code. Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org> |
||
|
Peter Zijlstra
|
1f03e8d291 |
locking/barriers: Replace smp_cond_acquire() with smp_cond_load_acquire()
This new form allows using hardware assisted waiting. Some hardware (ARM64 and x86) allow monitoring an address for changes, so by providing a pointer we can use this to replace the cpu_relax() with hardware optimized methods in the future. Requested-by: Will Deacon <will.deacon@arm.com> Suggested-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Ingo Molnar <mingo@kernel.org> |
||
|
Peter Zijlstra
|
331b6d8c7a |
locking/barriers: Validate lockless_dereference() is used on a pointer type
Use the type to validate the argument @p is indeed a pointer type. Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Alexey Dobriyan <adobriyan@gmail.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Paul McKenney <paulmck@linux.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/20160522104827.GP3193@twins.programming.kicks-ass.net Signed-off-by: Ingo Molnar <mingo@kernel.org> |
||
|
Rasmus Villemoes
|
d64e85d3e1 |
compiler.h: add support for malloc attribute
gcc as far back as at least 3.04 documents the function attribute __malloc__. Add a shorthand for attaching that to a function declaration. This was also suggested by Andi Kleen way back in 2002 [1], but didn't get applied, perhaps because gcc at that time generated the exact same code with and without this attribute. This attribute tells the compiler that the return value (if non-NULL) can be assumed not to alias any other valid pointers at the time of the call. Please note that the documentation for a range of gcc versions (starting from around 4.7) contained a somewhat confusing and self-contradicting text: The malloc attribute is used to tell the compiler that a function may be treated as if any non-NULL pointer it returns cannot alias any other pointer valid when the function returns and *that the memory has undefined content*. [...] Standard functions with this property include malloc and *calloc*. (emphasis mine). The intended meaning has later been clarified [2]: This tells the compiler that a function is malloc-like, i.e., that the pointer P returned by the function cannot alias any other pointer valid when the function returns, and moreover no pointers to valid objects occur in any storage addressed by P. What this means is that we can apply the attribute to kmalloc and friends, and it is ok for the returned memory to have well-defined contents (__GFP_ZERO). But it is not ok to apply it to kmemdup(), nor to other functions which both allocate and possibly initialize the memory with existing pointers. So unless someone is doing something pretty perverted kstrdup() should also be a fine candidate. [1] http://thread.gmane.org/gmane.linux.kernel/57172 [2] https://gcc.gnu.org/bugzilla/show_bug.cgi?id=56955 Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk> Cc: Christoph Lameter <cl@linux.com> Cc: Pekka Enberg <penberg@kernel.org> Cc: David Rientjes <rientjes@google.com> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Andi Kleen <ak@linux.intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
||
|
Ingo Molnar
|
8bc6782fe2 |
Merge commit 'fixes.2015.02.23a' into core/rcu
Conflicts: kernel/rcu/tree.c Signed-off-by: Ingo Molnar <mingo@kernel.org> |
||
|
Ingo Molnar
|
39a1142dbb |
Merge tag 'v4.5-rc6' into locking/core, to pick up fixes
Signed-off-by: Ingo Molnar <mingo@kernel.org> |
||
|
Boqun Feng
|
ad315455d3 |
sparse: Add __private to privatize members of structs
In C programming language, we don't have a easy way to privatize a member of a structure. However in kernel, sometimes there is a need to privatize a member in case of potential bugs or misuses. Fortunately, the noderef attribute of sparse is a way to privatize a member, as by defining a member as noderef, the address-of operator on the member will produce a noderef pointer to that member, and if anyone wants to dereference that kind of pointers to read or modify the member, sparse will yell. Based on this, __private modifier and related operation ACCESS_PRIVATE() are introduced, which could help detect undesigned public uses of private members of structs. Here is an example of sparse's output if it detect an undersigned public use: | kernel/rcu/tree.c:4453:25: warning: incorrect type in argument 1 (different modifiers) | kernel/rcu/tree.c:4453:25: expected struct raw_spinlock [usertype] *lock | kernel/rcu/tree.c:4453:25: got struct raw_spinlock [noderef] *<noident> Also, this patch improves compiler.h a little bit by adding comments for "#else" and "#endif". Signed-off-by: Boqun Feng <boqun.feng@gmail.com> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> |
||
|
Arnd Bergmann
|
b33c8ff443 |
tracing: Fix freak link error caused by branch tracer
In my randconfig tests, I came across a bug that involves several
components:
* gcc-4.9 through at least 5.3
* CONFIG_GCOV_PROFILE_ALL enabling -fprofile-arcs for all files
* CONFIG_PROFILE_ALL_BRANCHES overriding every if()
* The optimized implementation of do_div() that tries to
replace a library call with an division by multiplication
* code in drivers/media/dvb-frontends/zl10353.c doing
u32 adc_clock = 450560; /* 45.056 MHz */
if (state->config.adc_clock)
adc_clock = state->config.adc_clock;
do_div(value, adc_clock);
In this case, gcc fails to determine whether the divisor
in do_div() is __builtin_constant_p(). In particular, it
concludes that __builtin_constant_p(adc_clock) is false, while
__builtin_constant_p(!!adc_clock) is true.
That in turn throws off the logic in do_div() that also uses
__builtin_constant_p(), and instead of picking either the
constant- optimized division, and the code in ilog2() that uses
__builtin_constant_p() to figure out whether it knows the answer at
compile time. The result is a link error from failing to find
multiple symbols that should never have been called based on
the __builtin_constant_p():
dvb-frontends/zl10353.c:138: undefined reference to `____ilog2_NaN'
dvb-frontends/zl10353.c:138: undefined reference to `__aeabi_uldivmod'
ERROR: "____ilog2_NaN" [drivers/media/dvb-frontends/zl10353.ko] undefined!
ERROR: "__aeabi_uldivmod" [drivers/media/dvb-frontends/zl10353.ko] undefined!
This patch avoids the problem by changing __trace_if() to check
whether the condition is known at compile-time to be nonzero, rather
than checking whether it is actually a constant.
I see this one link error in roughly one out of 1600 randconfig builds
on ARM, and the patch fixes all known instances.
Link: http://lkml.kernel.org/r/1455312410-1058841-1-git-send-email-arnd@arndb.de
Acked-by: Nicolas Pitre <nico@linaro.org>
Fixes:
|