Nick Desaulniers
586d6f17d8
lib/string.c: implement stpcpy ...
commit 1e1b6d63d6340764e00356873e5794225a2a03ea upstream.
LLVM implemented a recent "libcall optimization" that lowers calls to
`sprintf(dest, "%s", str)` where the return value is used to
`stpcpy(dest, str) - dest`.
This generally avoids the machinery involved in parsing format strings.
`stpcpy` is just like `strcpy` except it returns the pointer to the new
tail of `dest`. This optimization was introduced into clang-12.
Implement this so that we don't observe linkage failures due to missing
symbol definitions for `stpcpy`.
Similar to last year's fire drill with: commit 5f074f3e192f
("lib/string.c: implement a basic bcmp")
The kernel is somewhere between a "freestanding" environment (no full
libc) and "hosted" environment (many symbols from libc exist with the
same type, function signature, and semantics).
As Peter Anvin notes, there's not really a great way to inform the
compiler that you're targeting a freestanding environment but would like
to opt-in to some libcall optimizations (see pr/47280 below), rather
than opt-out.
Arvind notes, -fno-builtin-* behaves slightly differently between GCC
and Clang, and Clang is missing many __builtin_* definitions, which I
consider a bug in Clang and am working on fixing.
Masahiro summarizes the subtle distinction between compilers justly:
To prevent transformation from foo() into bar(), there are two ways in
Clang to do that; -fno-builtin-foo, and -fno-builtin-bar. There is
only one in GCC; -fno-buitin-foo.
(Any difference in that behavior in Clang is likely a bug from a missing
__builtin_* definition.)
Masahiro also notes:
We want to disable optimization from foo() to bar(),
but we may still benefit from the optimization from
foo() into something else. If GCC implements the same transform, we
would run into a problem because it is not -fno-builtin-bar, but
-fno-builtin-foo that disables that optimization.
In this regard, -fno-builtin-foo would be more future-proof than
-fno-built-bar, but -fno-builtin-foo is still potentially overkill. We
may want to prevent calls from foo() being optimized into calls to
bar(), but we still may want other optimization on calls to foo().
It seems that compilers today don't quite provide the fine grain control
over which libcall optimizations pseudo-freestanding environments would
prefer.
Finally, Kees notes that this interface is unsafe, so we should not
encourage its use. As such, I've removed the declaration from any
header, but it still needs to be exported to avoid linkage errors in
modules.
Reported-by: Sami Tolvanen <samitolvanen@google.com>
Suggested-by: Andy Lavr <andy.lavr@gmail.com>
Suggested-by: Arvind Sankar <nivedita@alum.mit.edu>
Suggested-by: Joe Perches <joe@perches.com>
Suggested-by: Kees Cook <keescook@chromium.org>
Suggested-by: Masahiro Yamada <masahiroy@kernel.org>
Suggested-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Signed-off-by: Nick Desaulniers <ndesaulniers@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Tested-by: Nathan Chancellor <natechancellor@gmail.com>
Cc: <stable@vger.kernel.org>
Link: https://lkml.kernel.org/r/20200914161643.938408-1-ndesaulniers@google.com
Link: https://bugs.llvm.org/show_bug.cgi?id=47162
Link: https://bugs.llvm.org/show_bug.cgi?id=47280
Link: https://github.com/ClangBuiltLinux/linux/issues/1126
Link: https://man7.org/linux/man-pages/man3/stpcpy.3.html
Link: https://pubs.opengroup.org/onlinepubs/9699919799/functions/stpcpy.html
Link: https://reviews.llvm.org/D85963
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-10-01 20:40:19 +02:00
Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial
2016-03-17 21:38:27 -07:00
fonts: Add 6x10 font
2014-10-09 11:35:48 +03:00
lz4: fix bogus gcc warning
2017-09-02 07:07:54 +02:00
lzo: check for length overrun in variable length encoding.
2014-09-28 11:08:01 +02:00
lib/mpi: Fix 64-bit MIPS build with Clang
2020-06-20 10:24:15 +02:00
lib: raid6: fix awk build warnings
2019-12-21 10:42:00 +01:00
rslib: Fix handling of of caller provided syndrome
2019-08-04 09:33:23 +02:00
lib/xz: enable all filters by default in Kconfig
2014-06-04 16:54:18 -07:00
zlib_deflate/deftree: remove bi_reverse()
2015-09-10 13:29:01 -07:00
lib/zlib: remove outdated and incorrect pre-increment optimization
2020-06-30 15:38:29 -04:00
ASN.1: check for error from ASN1_OP_END__ACT actions
2017-12-14 09:28:12 +01:00
assoc_array: Fix shortcut creation
2019-03-23 13:19:42 +01:00
locking/atomic: Implement atomic{,64,_long}_fetch_{add,sub,and,andnot,or,xor}{,_relaxed,_acquire,_release}()
2016-06-16 10:48:32 +02:00
atomic64: no need for CONFIG_ARCH_HAS_ATOMIC64_DEC_IF_POSITIVE
2016-10-07 18:46:30 -07:00
syscalls: implement execveat() system call
2014-12-13 12:42:51 -08:00
bitmap: Add bitmap_alloc(), bitmap_zalloc() and bitmap_free()
2020-01-29 10:24:41 +01:00
ARM: 8187/1: add CONFIG_HAVE_ARCH_BITREVERSE to support rbit instruction
2014-12-22 16:43:06 +00:00
kprobes: Prohibit probing on bsearch()
2019-04-05 22:29:11 +02:00
treewide: Remove old email address
2015-11-23 09:44:58 +01:00
lib/bug.c: use common WARN helper
2016-03-17 15:09:34 -07:00
random: replace non-blocking pool with a Chacha20-based CRNG
2016-07-03 00:57:23 -04:00
ipv4: Update parameters for csum_tcpudp_magic to their original types
2016-03-13 23:55:13 -04:00
lib/clz_ctz.c: add prototype declarations in lib/clz_ctz.c
2014-04-03 16:21:12 -07:00
lib/cmdline.c: fix get_options() overflow while parsing ranges
2017-06-29 13:00:28 +02:00
audit: Add generic compat syscall support
2014-03-20 10:11:35 -04:00
fault-injection/cpu: Convert to hotplug state machine
2016-09-19 21:44:31 +02:00
sched/topology: Rename topology_thread_cpumask() to topology_sibling_cpumask()
2015-05-27 15:22:15 +02:00
sched/fair, cpumask: Export for_each_cpu_wrap()
2017-07-21 07:42:23 +02:00
lib: crc-itu-t.[ch] fix 0x0x prefix in integer constants
2015-05-26 15:26:43 +02:00
lib: introduce crc_t10dif_update()
2015-05-30 22:42:24 -07:00
lib/crc7: Shift crc7() output left 1 bit
2014-05-16 14:26:52 -04:00
crc32: use ktime_get_ns() for measurement
2016-08-02 19:35:08 -04:00
kbuild: include core debug info when DEBUG_INFO_REDUCED
2015-06-11 15:08:32 +02:00
locking/lockdep: Fix debug_locks off performance problem
2018-11-13 11:16:48 -08:00
debugobjects: avoid recursive calls with kmemleak
2018-12-17 09:38:35 +01:00
lib/decompress: set the compressor name to NULL on error
2015-07-17 16:39:54 -07:00
lib/decompressors: use real out buf size for gunzip with kernel
2015-09-10 13:29:01 -07:00
lib/decompressors: use real out buf size for gunzip with kernel
2015-09-10 13:29:01 -07:00
lib/decompressors: use real out buf size for gunzip with kernel
2015-09-10 13:29:01 -07:00
lib/decompress_unlzma: Do a NULL check for pointer
2015-09-10 13:29:01 -07:00
lib/decompressors: use real out buf size for gunzip with kernel
2015-09-10 13:29:01 -07:00
lib/decompressors: use real out buf size for gunzip with kernel
2015-09-10 13:29:01 -07:00
devres: allow const resource arguments
2020-01-29 10:24:28 +01:00
lib/digsig: fix dereference of NULL user_key_payload
2017-10-27 10:38:08 +02:00
lib/div64.c: off by one in shift
2019-04-20 09:07:54 +02:00
dma-debug: add a schedule point in debug_dma_dump_mappings()
2020-01-04 13:40:44 +01:00
dma-mapping: use unsigned long for dma_attrs
2016-08-04 08:50:07 -04:00
dump_stack: avoid the livelock of the dump_lock
2019-11-12 19:15:43 +01:00
dyndbg: fix a BUG_ON in ddebug_describe_flags
2020-08-21 11:01:59 +02:00
lib/dynamic_queue_limits.c: simplify includes
2015-02-12 18:54:15 -08:00
lib/cpio: Make find_cpio_data()'s offset arg optional
2016-06-08 11:04:19 +02:00
extable: add support for relative extables to search and sort routines
2016-02-24 14:57:26 +00:00
fault-inject: fix inverted interval/probability values in printk
2015-10-23 17:55:10 +09:00
lib: add fdt_empty_tree.c
2014-04-30 19:49:37 +01:00
lib: rename lib/find_next_bit.c to lib/find_bit.c
2015-04-17 09:03:54 -04:00
lib+mm: fix few spelling mistakes
2016-02-15 11:18:23 +01:00
lib/GCD.c: use binary GCD algorithm instead of Euclidean
2016-05-20 17:58:30 -07:00
lib: crc32: constify crc32 lookup table
2015-02-13 21:21:35 -08:00
lib/genalloc.c: include vmalloc.h
2019-12-05 15:35:05 +01:00
lib/glob.c: add CONFIG_GLOB_SELFTEST
2014-08-06 18:01:25 -07:00
lib/halfmd4.c: use rol32 inline function in the ROUND macro
2015-11-06 17:50:42 -08:00
lib/hexdump.c: truncate output in case of overflow
2015-11-06 17:50:42 -08:00
x86/hweight: Get rid of the special calling convention
2016-06-08 15:01:02 +02:00
mm, page_alloc: distinguish between being unable to sleep, unwilling to sleep and avoiding waking kswapd
2015-11-06 17:50:42 -08:00
lib/int_sqrt: optimize initial value compute
2019-04-05 22:29:04 +02:00
lib/interval_tree.c: simplify includes
2015-02-12 18:54:15 -08:00
lib/interval_tree_test.c: allow users to limit scope of endpoint
2018-12-21 14:11:30 +01:00
Kconfig: rename HAS_IOPORT to HAS_IOPORT_MAP
2014-04-07 16:36:11 -07:00
lib/iomap_copy.c: add __ioread32_copy()
2016-01-20 17:09:18 -08:00
Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/sparc
2015-11-05 16:34:48 -08:00
lib/iommu-helper: skip to next segment
2016-08-02 19:35:07 -04:00
ioremap: Update pgtable free interfaces with addr
2018-08-17 20:59:29 +02:00
new privimitive: iov_iter_revert()
2017-04-21 09:31:21 +02:00
This adds a new gcc plugin named "latent_entropy". It is designed to
2016-10-15 10:03:15 -07:00
lib/is_single_threaded.c: change current_is_single_threaded() to use for_each_thread()
2015-11-06 17:50:42 -08:00
lib/kasprintf.c: add sanity check to kvasprintf
2016-01-16 11:17:27 -08:00
Merge branch 'akpm' (patches from Andrew)
2016-10-07 21:38:00 -07:00
kmemleak: increase DEBUG_KMEMLEAK_EARLY_LOG_SIZE default to 16K
2019-10-07 18:53:19 +02:00
mm, kasan: switch SLUB to stackdepot, enable memory quarantine for SLUB
2016-07-28 16:07:41 -07:00
kgdb: depends on VT
2016-05-23 17:04:14 -07:00
ubsan: allow to disable the null sanitizer
2016-09-20 14:26:08 +02:00
Partially revert "kfifo: fix kfifo_alloc() and kfifo_init()"
2020-01-29 10:24:30 +01:00
scsi: klist: Make it safe to use klists in atomic context
2018-10-03 17:01:45 -07:00
kobject: Export kobject_get_unless_zero()
2020-01-14 20:04:25 +01:00
lib/kobject_uevent.c: remove redundant include
2015-02-12 18:54:15 -08:00
lib/kstrtox.c: smaller _parse_integer()
2016-10-11 15:06:30 -07:00
block: fix blk_stack_limits() regression due to lcm() change
2015-03-31 09:45:50 -06:00
crypto: Work around deallocated stack frame reference gcc bug on sparc.
2017-06-24 07:11:17 +02:00
list: kill list_force_poison()
2016-03-09 15:43:42 -08:00
lib/list_sort: use late_initcall to hook in self tests
2015-06-16 14:12:35 -04:00
lib/llist.c: fix data race in llist_del_first
2015-11-06 17:50:42 -08:00
locking/selftest: Fix output since KERN_CONT changes
2016-11-25 07:12:19 +01:00
locking/lockref: Remove homebrew cmpxchg64_relaxed() macro definition
2015-08-12 11:59:04 +02:00
lru_cache: Converted lc_seq_printf_status to return void
2015-11-25 09:22:02 -07:00
ubsan: build ubsan.c more conservatively
2020-05-27 16:42:00 +02:00
lib/md5.c: simplify include
2015-02-12 18:54:15 -08:00
mac_pton: Use bool not int return
2014-06-25 17:45:43 -07:00
net: Add support for CHANGEUPPER notifier error injection
2015-12-03 11:49:23 -05:00
libnl: fix help of _64bit functions
2016-04-23 20:13:24 -04:00
nmi_backtrace: generate one-line reports for idle cpus
2016-10-07 18:46:30 -07:00
include/linux/nodemask.h: create next_node_in() helper
2016-05-19 19:12:14 -07:00
509: fix printing uninitialized stack memory when OID is empty
2018-02-25 11:05:48 +01:00
once: make helper generic for calling functions once
2015-10-08 05:26:36 -07:00
libnvdimm for 4.3:
2015-09-08 14:35:59 -07:00
percpu-refcount: init ->confirm_switch member properly
2016-08-11 13:52:23 -04:00
percpu_counter: update debugobjects fixup callbacks return type
2016-05-19 19:12:14 -07:00
mm, page_alloc: rename __GFP_WAIT to __GFP_RECLAIM
2015-11-06 17:50:42 -08:00
lib/plist.c: remove redundant include
2015-02-12 18:54:16 -08:00
Revert "radix tree test suite: fix compilation"
2016-12-09 10:41:42 -08:00
random32: remove net_rand_state from the latent entropy gcc plugin
2020-08-21 11:01:52 +02:00
lib/ratelimit.c: use deferred printk() version
2017-10-12 11:51:19 +02:00
Introduce rb_replace_node_rcu()
2016-07-06 10:51:14 +01:00
lib/rbtree-test: lower default params
2018-12-21 14:11:30 +01:00
rhashtable: add schedule points
2018-10-18 09:13:24 +02:00
sbitmap: initialize weight to zero
2016-09-19 08:19:40 -06:00
lib/scatterlist.c: adjust indentation in __sg_alloc_table
2020-02-28 15:42:41 +01:00
seq_buf: Make seq_buf_puts() null-terminate the buffer
2019-02-12 19:44:57 +01:00
lib: scatterlist: move SG pool code from SCSI driver to lib/sg_pool.c
2016-04-15 16:53:14 -04:00
lib: scatterlist: add sg splitting function
2015-08-24 14:28:01 -06:00
lib: EXPORT_SYMBOL sha_init
2015-03-23 22:12:08 -04:00
lib/show_mem.c: correct reserved memory calculation
2015-09-08 15:35:28 -07:00
siphash: implement HalfSipHash1-3 for hash tables
2019-08-25 10:51:42 +02:00
percpu: add preemption checks to __this_cpu ops
2014-04-07 16:36:14 -07:00
lib/sort: Add 64 bit swap function
2015-06-25 17:00:40 -07:00
lib/stackdepot.c: fix global out-of-bounds in stack_slabs
2020-02-28 15:42:50 +01:00
lib/stmp_device.c: replace module.h include
2015-02-12 18:54:16 -08:00
lib/string.c: implement stpcpy
2020-10-01 20:40:19 +02:00
string_helpers: add kstrdup_quotable_file
2016-04-21 10:47:26 +10:00
mm/uaccess: Use 'unsigned long' to placate UBSAN warnings on older GCC versions
2019-05-31 06:48:17 -07:00
mm/uaccess: Use 'unsigned long' to placate UBSAN warnings on older GCC versions
2019-05-31 06:48:17 -07:00
swiotlb: clean up reporting
2018-12-13 09:20:29 +01:00
lib/syscall: Clear return values when no stack
2017-04-08 09:30:35 +02:00
kstrto*: accept "-0" for signed conversion
2015-09-10 13:29:01 -07:00
lib/test-string_helpers.c: fix and improve string_get_size() tests
2016-02-03 08:28:43 -08:00
test_bitmap: unit tests for lib/bitmap.c
2016-02-19 22:54:09 -05:00
test_bpf: Fix testing with CONFIG_BPF_JIT_ALWAYS_ON=y on other arches
2018-11-10 07:42:54 -08:00
test: firmware_class: add asynchronous request trigger
2016-01-07 13:44:22 -07:00
lib/test_hash.c: fix warning in preprocessor symbol evaluation
2016-09-01 17:52:01 -07:00
test_hexdump: use memcpy instead of strncpy
2018-12-08 13:05:04 +01:00
lib/test_kasan.c: fix memory leak in kmalloc_oob_krealloc_more()
2020-02-14 16:31:00 -05:00
mm, printk: introduce new format string for flags
2016-03-15 16:55:16 -07:00
rhashtable-test: Fix max_size parameter description
2016-08-08 12:52:42 -07:00
siphash: implement HalfSipHash1-3 for hash tables
2019-08-25 10:51:42 +02:00
locking/static_keys: Provide a selftest
2015-08-03 11:51:12 +02:00
locking/static_keys: Avoid nested functions
2016-02-09 10:27:29 +01:00
usercopy: Adjust tests to deal with SMAP/PAN
2017-06-14 15:06:05 +02:00
lib/uuid: add a test module
2016-05-30 15:26:57 -07:00
lib/textsearch.c: remove textsearch_put reference from comments
2014-10-14 02:18:14 +02:00
timerqueue: Let timerqueue_add/del return information
2015-04-22 17:06:49 +02:00
ubsan: Fix nasty -Wbuiltin-declaration-mismatch GCC-9 warnings
2019-05-10 17:52:07 +02:00
lib/ubsan: add type mismatch handler for new GCC/Clang
2018-02-17 13:21:20 +01:00
lib/ucs2_string: Speed up ucs2_utf8size()
2016-09-09 16:08:46 +01:00
lib/uuid.c: use correct offset in uuid parser
2016-05-30 15:26:57 -07:00
lib/vsprintf: Remove atomic-unsafe support for %pCr
2018-07-03 11:23:06 +02:00
lib/win_minmax: windowed min or max estimator
2016-09-21 00:22:59 -04:00
586d6f17d8