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2021-08-09make __{en,de}code_dotted into macrosmirabilos
they merely call dn_{comp,expand} slightly rearranging the arguments Signed-off-by: mirabilos <mirabilos@evolvis.org>
2021-08-09actually remove the ifdeffed-out code from the previous commitmirabilos
Signed-off-by: mirabilos <mirabilos@evolvis.org>
2021-08-09libc/inet/resolv.c: use dn_{comp,expand} for __{en,de}code_dottedmirabilos
Minimal-invasive change: just ifdeffing away the older code. There is no reason to have two different sets of functions doing the same thing, one used in half the code and another, doing less escaping, in the other half; just use one. Signed-off-by: mirabilos <mirabilos@evolvis.org>
2021-02-19fcntl.h: Make F_DUPFD_CLOEXEC if _USE_XOPEN2K8Paul Cercueil
The F_DUPFD_CLOEXEC flag was added in POSIX 2008.09. Signed-off-by: Paul Cercueil <paul@crapouillou.net>
2021-01-28use renameat2 syscall, when renameat isn't availableWaldemar Brodkorb
2021-01-27fix umount2 compilation for alpha on Linux 5.xWaldemar Brodkorb
2021-01-27sh: Add 64-bit time types from kernelGeoffrey Le Gourriérec
Building uclibc 1.0.37 for SuperH architecture with linux-headers 5.10.7 fails at libpthread level due to missing time-related data structures, usually defined by the kernel. Define those missing data structures in SuperH-specific kernel_types.h. Context: building for sh4eb-r2d[1] and sh4-r2d[1] boards emulations for QEMU using the buildroot image generation tool. Regarding the issue, a patch[3] was already issued in the kernel some time ago, which aimed to solve precisely this problem. After coming up with a quick and dirty patch for buildroot modifying Linux headers[4], some discussion was sparked on the subject with Linux folks[5]. Some analyzing later, conclusion was that: 1) Previously mentioned patch[4] was fixing the symptom, not the ill 2) SuperH-specific code in uclibc could be patched instead, to solve the problem for other use cases (e.g. building just a toolchain) [1] https://git.buildroot.net/buildroot/tree/configs/qemu_sh4eb_r2d_defconfig?h=2020.02.9 [2] https://git.buildroot.net/buildroot/tree/configs/qemu_sh4_r2d_defconfig?h=2020.02.9 [3] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=fc94cf2092c7c1267fa2deb8388d624f50eba808 [4] https://git.buildroot.net/buildroot/commit/?id=742f37de8d0e3797698411dfc6a63bd7e98aafe2 [5] https://patchwork.kernel.org/project/linux-sh/patch/20210123165652.10884-1-geoffrey.legourrierec@gmail.com/ Signed-off-by: Geoffrey Le Gourriérec <geoffrey.legourrierec@gmail.com>
2020-12-23stdlib: fix potential UB and integer overflow with huge allocations using ↵Yann Sionneau
malloc-simple allocator Two things are fixed by this commit: 1/ It is wrong to allocate an object of size > PTRDIFF_MAX. It is explained in this thread: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63303 2/ There was a possible integer overflow in both malloc() and memalign() implementations of stdlib/malloc-simple. The malloc() integer overflow issue is fixed by the side effect of fixing the PTRDIFF_MAX issue. The memalign() one is fixed by adding a comparison. Signed-off-by: Yann Sionneau <yann@sionneau.net>
2020-10-19hasmntopt: better option matchingYann Sionneau
Previous implementation was respecting the man page description of what the function should do. Also the function does not seem to be defined by POSIX. But... to be really useful the function needs to handle option matching and not just substring matching. This is copy pasted from glibc. This fixes issue reported by https://github.com/wbx-github/uclibc-ng/issues/8 that can happen for instance there: https://github.com/frida/glib/blob/master/gio/gunixmounts.c#L622 Signed-off-by: Yann Sionneau <yann@sionneau.net>
2020-10-02kvx: add support for kvx arch to uClibc-ngYann Sionneau
This commit adds support for Kalray VLIW family (kvx) Kalray kv3 core is embedded in Kalray Coolidge SoC. This core which is the third of the KV family has the following features: 32/64 bits execution mode 6-issue VLIW architecture 64 x 64bits general purpose registers SIMD instructions little-endian In order to build a usable toolchain, build scripts are provided at the following address: https://github.com/kalray/build-scripts. Kalray uses FOSS which is available at https://github.com/kalray This includes Linux kernel, uClibc-ng, gcc, binutils, etc. Signed-off-by: Clément Léger <cleger@kalray.eu> Signed-off-by: Guillaume Thouvenin <gthouvenin@kalray.eu> Signed-off-by: Laurent Thevenoux <lthevenoux@kalray.eu> Signed-off-by: Marc Poulhies <mpoulhies@kalray.eu> Signed-off-by: Marius Gligor <mgligor@kalray.eu> Signed-off-by: Yann Sionneau <ysionneau@kalray.eu>
2020-09-22Fix warning due to unused variable in strlenYann Sionneau
Fixes this: libc/string/generic/strlen.c: In function 'strlen': libc/string/generic/strlen.c:31:31: warning: variable 'magic_bits' set but not used [-Wunused-but-set-variable] unsigned long int longword, magic_bits, himagic, lomagic; ^~~~~~~~~~ Signed-off-by: Yann Sionneau <ysionneau@kalray.eu>
2020-09-22Fix warning about macro redefinitionYann Sionneau
Fixes this: libc/misc/internals/tempname.c: In function 'brain_damaged_fillrand': libc/misc/internals/tempname.c:155:0: warning: "L" redefined #define L ((UINT32_MAX % NUM_LETTERS + 1) % NUM_LETTERS) In file included from ./libpthread/nptl/sysdeps/unix/sysv/linux/lowlevellock.h:24:0, from ./include/bits/libc-lock.h:35, from ./include/bits/stdio-lock.h:22, from ./include/bits/uClibc_mutex.h:73, from ./include/bits/uClibc_stdio.h:83, from ./include/stdio.h:71, from libc/misc/internals/tempname.c:35: ./libc/sysdeps/linux/kvx/sysdep.h:40:0: note: this is the location of the previous definition # define L(name) $L##name Signed-off-by: Yann Sionneau <ysionneau@kalray.eu>
2020-09-22Fix warning about missing const qualifierYann Sionneau
Fixes this: In file included from libc/misc/fnmatch/fnmatch.c:235:0: libc/misc/fnmatch/fnmatch_loop.c: In function 'internal_fnmatch': libc/misc/fnmatch/fnmatch_loop.c:207:21: warning: initialization discards 'const' qualifier from pointer target type [-Wdiscarded-qualifiers] CHAR *p_init = p; ^ libc/misc/fnmatch/fnmatch_loop.c:208:21: warning: initialization discards 'const' qualifier from pointer target type [-Wdiscarded-qualifiers] CHAR *n_init = n; Signed-off-by: Yann Sionneau <ysionneau@kalray.eu>
2020-09-21Support b64_ntop(), b64_pton() (bsd-compat)Waldemar Brodkorb
Signed-off-by: akater <nuclearspace@gmail.com>
2020-09-15Fix memory corruption due to struct stat fieldYann Sionneau
Kernel stat/stat64 structure and uClibc-ng ones were not in sync regarding the timespec fields. Kernel had them but uClibc did not expose it in some cases. Man page says that stat struct should have timespec fields if: * _POSIX_C_SOURCE is defined to 200809L or greater or * _XOPEN_SOURCE is defined to 700 or greater or * _BSD_SOURCE is defined or * _SVID_SOURCE is defined In the case of buildroot vim build, neither _BSD_SOURCE nor _SVID_SOURCE were defined. Only _POSIX_C_SOURCE and _XOPEN_SOURCE were defined. uClibc-ng header only checked for _BSD_SOURCE and _SVID_SOURCE via __USE_MISC. This patch adds a check to __USE_XOPEN2K8 which is defined if _POSIX_C_SOURCE >= 200809L or _XOPEN_SOURCE >= 700 This for instance fixes a crash at startup of vim (not the busybox one) on aarch64 and all other arch where in kernel STAT_HAVE_NSEC is set and where stat.h in uClibc-ng comes from libc/sysdeps/linux/common-generic/bits Signed-off-by: Yann Sionneau <ysionneau@kalray.eu>
2020-09-02Revert "Fix static linking with GCC-10"Waldemar Brodkorb
This reverts commit 5b58a1ebd89a4f05778441814e81817c82193fa3. This breaks all static builds earlier to gcc 10 :( Bad testing on my side.
2020-08-19Add {name, open}_to_handle_at() implementationPetr Vorel
copied from musl 1.2.1. Signed-off-by: Petr Vorel <petr.vorel@gmail.com>
2020-08-17riscv64: add __riscv_flush_icacheWaldemar Brodkorb
Always use the systemcall as uClibc-ng has no vdso support. Tested with libffi and python in qemu-system-riscv64.
2020-08-15sys/random.h include stddef.hWaldemar Brodkorb
Reported-By: akater <nuclearspace@gmail.com>
2020-08-11Fix static linking with GCC-10Lance Fredrickson
Starting with GCC-10 multiple definitions of global variables by will be rejected. https://gcc.gnu.org/gcc-10/porting_to.html This fixes multiple definitions of _dl_pagesize and _dl_tls_static_size while attempting static linking. Of course this only occurs when compiling something that requires these symbols. First patch submission so hopefully all done correctly. thanks, Lance Fredrickson From e0686f7c03ce8e51ccffefeb6365e50311e6dd10 Mon Sep 17 00:00:00 2001 From: lancethepants <lancethepants@gmail.com> Date: Wed, 15 Jul 2020 13:09:26 -0600 Subject: [PATCH] Starting with GCC-10 multiple definitions of global variables by will be rejected. This fixes multiple definitions of _dl_pagesize and _dl_tls_static_size while attempting static linking.
2020-08-11xtensa: add exclusive access supportMax Filippov
Add XCHAL definitions for S32C1I and EXCLUSIVE options to xtensa-config.h, include it in places that implement atomic operations and add implementations with exclusive access option opcodes. Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>
2020-08-11xtensa: relax memory constraint in atomic assemblyMax Filippov
Replace "a" constraints with "+m" to avoid forcing atomic variable address into a register and let the compiler use non-zero offset in load/store opcodes. Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>
2020-07-02Rename __unused struct members to include a namespaceEd Wildgoose
Rename various spare fields in structs to include a namespace This should avoid accidental clashes with uses of the __unused symbol in upstream projects. eg currently it causes a compile error in dhcpcd 8.x due to their re-use of the __unused symbol as a macro This follows the style of glibc which does something equivalent
2020-06-19inet: add sockatmark implementationClement Leger
Import musl C sockatmark implementation into uClibc-ng. Signed-off-by: Clement Leger <cleger@kalray.eu> Acked-by: Yann Sionneau <ysionneau@kalray.eu>
2020-05-17mips: Do not include hi and lo in __SYSCALL_CLOBBERS for R6Romain Naour
From [1] "GCC 10 (PR 91233) won't silently allow registers that are not architecturally available to be present in the clobber list anymore, resulting in build failure for mips*r6 targets in form of: ... .../sysdep.h:146:2: error: the register ‘lo’ cannot be clobbered in ‘asm’ for the current target 146 | __asm__ volatile ( \ | ^~~~~~~ This is because base R6 ISA doesn't define hi and lo registers w/o DSP extension. This patch provides the alternative definitions of __SYSCALL_CLOBBERS for r6 targets that won't include those registers." [1] https://sourceware.org/git/?p=glibc.git;a=commit;h=020b2a97bb15f807c0482f0faee2184ed05bcad8 Signed-off-by: Romain Naour <romain.naour@gmail.com> Cc: Waldemar Brodkorb <wbx@openadk.org>
2020-04-01statx: make include conditional, fixes non-csky arch buildroot buildsWaldemar Brodkorb
2020-04-01Resolve bug when using unusual MALLOC_ALIGNMENTEyal Itkin
Safe-Linking alignment checks should be done on the user's buffer and not the mchunkptr. The new check adds support for cases in which: MALLOC_ALIGNMENT != 2*(sizeof(size_t)) The default case for both 32 bits and 64 bits was already supported, and this patch adds support for the described irregular case.
2020-02-19malloc: add missing header for some arch (alpha)Waldemar Brodkorb
2020-02-16Add Safe-Linking to fastbinsEyal Itkin
Safe-Linking is a security mechanism that protects single-linked lists (such as the fastbins) from being tampered by attackers. The mechanism makes use of randomness from ASLR (mmap_base), and when combined with chunk alignment integrity checks, it protects the pointers from being hijacked by an attacker. While Safe-Unlinking protects double-linked lists (such as the small bins), there wasn't any similar protection for attacks against single-linked lists. This solution protects against 3 common attacks: * Partial pointer override: modifies the lower bytes (Little Endian) * Full pointer override: hijacks the pointer to an attacker's location * Unaligned chunks: pointing the list to an unaligned address The design assumes an attacker doesn't know where the heap is located, and uses the ASLR randomness to "sign" the single-linked pointers. We mark the pointer as P and the location in which it is stored as L, and the calculation will be: * PROTECT(P) := (L >> PAGE_SHIFT) XOR (P) * *L = PROTECT(P) This way, the random bits from the address L (which start at the bits in the PAGE_SHIFT position), will be merged with the LSB of the stored protected pointer. This protection layer prevents an attacker from modifying the pointer into a controlled value. An additional check that the chunks are MALLOC_ALIGNed adds an important layer: * Attackers can't point to illegal (unaligned) memory addresses * Attackers must guess correctly the alignment bits On standard 32 bit Linux machines, an attacker will directly fail 7 out of 8 times, and on 64 bit machines it will fail 15 out of 16 times. The proposed solution adds 3-4 asm instructions per malloc()/free() and therefore has only minor performance implications if it has any. A similar protection was added to Chromium's version of TCMalloc in 2013, and according to their documentation the performance overhead was less than 2%. Signed-off-by: Eyal Itkin <eyalit@checkpoint.com>
2020-02-07aarch64/bits: provide sigstack.hVladimir Murzin
It fixes tst-signal6 and friends. Signed-off-by: Vladimir Murzin <vladimir.murzin@arm.com>
2020-02-07aarch64/sys: update ucontext.hVladimir Murzin
It fixes tst-cancel1 and friends. Signed-off-by: Vladimir Murzin <vladimir.murzin@arm.com>
2020-02-07common/bits: Fix ipc_perm and semid_ds definitions for 64-bit archesVladimir Murzin
It fixes: FAIL sem got 1 expected 0 failed: incorrect sem_nsems! semget(IPC_CREAT) = 0 semctl(k) = 0 sem_nsems = 0 for aarch64. Signed-off-by: Vladimir Murzin <vladimir.murzin@arm.com>
2020-02-03csky: add statx conditionalsWaldemar Brodkorb
Similar to glibc commit https://sourceware.org/git/?p=glibc.git;a=commit;h=6bbfc5c09fc5b5e3d4a0cddbbd4e2e457767dae7 we need to handle Linux kernel change, which removed stat64 family from default syscall set. Signed-off-by: Waldemar Brodkorb <wbx@openadk.org> Signed-off-by: Waldemar Brodkorb <wbrodkorb@conet.de>
2020-01-30Fix map_newlink abort when interface list changes during getifaddrsVincent Hou
map_newlink() may abort when interface list changed between netlink request for getting interfaces and getting addresses. This commit is ported from the same change from glibc commit. Signed-off-by: Vincent Hou <vincent.houyi@gmail.com>
2020-01-30poll: avoid calling select with empty sets which hangs the processYann Sionneau
Avoid calling select with empty sets which hangs the process This makes uClibc-ng act like glibc and musl Without this fix the test_poll of python3 testsuite hangs forever Scenario of the issue: If you call poll with only invalid file descriptors, like in python3 testsuite (https://github.com/python/cpython/blob/master/Lib/test/test_poll.py#L83) You will go through uClibc poll emulation code, which is based on select syscall. Your first call to select will fail, it will return -1 and errno will be set to EBADF: https://github.com/wbx-github/uclibc-ng/blob/master/libc/sysdeps/linux/common/poll.c#L120 Then you will go through the for loop which tests individually each file descriptor by calling select on each one: https://github.com/wbx-github/uclibc-ng/blob/master/libc/sysdeps/linux/common/poll.c#L163 each call will also return -1 with errno being equal to EBADF. Therefore all pollfd will have the POLLNVAL flag in their respective revents field. And, the most important, rset/wset/xset will stay empty. Then the for loop ends, the "continue" makes the while loop run again. The following select() is run again: https://github.com/wbx-github/uclibc-ng/blob/master/libc/sysdeps/linux/common/poll.c#L120 But this time the sets are empty. If the poll was called with timeout set to -1, this select will hang forever because there is no timeout and the sets are empty so no event will ever wake it up. test program: int main(void) { struct pollfd pfd; int ret; int pipe_fds[2]; pipe(pipe_fds); close(pipe_fds[0]); close(pipe_fds[1]); pfd.fd = pipe_fds[0]; pfd.events = POLLIN | POLLOUT | POLLPRI; pfd.revents = 0; ret = poll(&pfd, 1, -1); printf("ret: %d\n", ret); if (ret < 0) printf("error: %s", strerror(errno)); else { puts("revents: "); if (pfd.revents & POLLERR) printf(" POLLERR"); if (pfd.revents & POLLHUP) printf(" POLLHUP"); if (pfd.revents & POLLNVAL) printf(" POLLNVAL"); puts(""); } return 0; } This hangs on uClibc-ng aarch64 and Kalray's arch (kv3) but does the following on musl and glibc: " ret: 1 revents: POLLNVAL " strace output of this program with uClibc *without* the patch applied: pselect6(4, [3], [3], [3], NULL, NULL) = -1 EBADF (Bad file descriptor) pselect6(4, [3], [3], [3], {tv_sec=0, tv_nsec=0}, NULL) = -1 EBADF (Bad file descriptor) pselect6(0, 0x7ffffffb80, 0x7ffffffb68, 0x7ffffffb50, NULL, NULL (never finishes) strace output of this program with uClibc *with* the patch applied: pselect6(4, [3], [3], [3], NULL, NULL) = -1 EBADF (Bad file descriptor) pselect6(4, [3], [3], [3], {tv_sec=0, tv_nsec=0}, NULL) = -1 EBADF (Bad file descriptor) write(1, "ret: 1\n", 7ret: 1 ) = 7 write(1, "revents: \n", 10revents: ) = 10 write(1, " POLLNVAL\n", 10 POLLNVAL ) = 10 exit_group(0) = ? +++ exited with 0 +++
2020-01-28fix getenv bugAta, John (US)
The getenv() library call can trap under certain conditions. It compares the passed in environment variable name (var) with the name=variables (*ep) in the environment area and returns a pointer to the value in the environment if it exists. To accomplish this, it does a memcmp() using the length of the passed in name (len) for each environment variable (*ep) against the passed in name ( var). So memcmp will attempt to scan both strings for len bytes. However, if for some reason, len is equal to or greater than 16 and longer than the length of the *ep in the environment and the *ep resides near the end of a page boundary while the next page is not present or mapped, the memcmp could trap with a sigsegv error while continuing the scan with the optimization read-ahead. However, if strncmp is used instead, there is no problem since both source and destination scanning will stop when either reaches a terminating NULL
2019-11-17fix PTRAVE_EVENT_SECCOMP typo in ptrace.hJoris Vink
Hi, This diff fixes a typo in the PTRACE_EVENT_SECCOMP event code. The typo itself was introduced in 2012 when syncing with glibc header files and was itself fixed in 2013 in the glibc headers.
2019-11-08riscv64: implement NPTL/TLSWaldemar Brodkorb
basically from or1k port of uClibc-ng, with fixes for structures in pthreadtypes.h from 64 bit architectures. 18 testsuite failures counted.
2019-11-06riscv64: lazy relocations do not work like sparc/m68kWaldemar Brodkorb
2019-11-05implement fexecve from glibcWaldemar Brodkorb
2019-11-01riscv64: add shared library supportWaldemar Brodkorb
2019-10-30Make __syscall_error return long, as expected by syscall() callersCarlos Santos
The return type of syscall() is long so __syscall_error, which is jumped to by syscall handlers to stash an error number into errno, must return long too otherwhise it returs 4294967295L instead of -1L. For example, syscall for x86_64 is defined in libc/sysdeps/linux/x86_64/syscall.S as syscall: movq %rdi, %rax /* Syscall number -> rax. */ movq %rsi, %rdi /* shift arg1 - arg5. */ movq %rdx, %rsi movq %rcx, %rdx movq %r8, %r10 movq %r9, %r8 movq 8(%rsp),%r9 /* arg6 is on the stack. */ syscall /* Do the system call. */ cmpq $-4095, %rax /* Check %rax for error. */ jae __syscall_error /* Branch forward if it failed. */ ret /* Return to caller. */ In libc/sysdeps/linux/x86_64/__syscall_error.c, __syscall_error is defined as int __syscall_error(void) attribute_hidden; int __syscall_error(void) { register int err_no __asm__ ("%rcx"); __asm__ ("mov %rax, %rcx\n\t" "neg %rcx"); __set_errno(err_no); return -1; } So __syscall_error returns -1 as a 32-bit int in a 64-bit register, %rax (0x00000000ffffffff, whose decimal value is decimal 4294967295) and a test like this always returns false: if (syscall(number, ...) == -1) foo(); Fix the error by making __syscall_error return a long, like syscall(). The problem can be circumvented by the caller by coercing the returned value to int before comparing it to -1: if ((int) syscall(number, ...) == -1) foo(); The same problem probably occurs on other 64-bit systems but so far only x86_64 was tested, so this change must be considered experimental. Signed-off-by: Carlos Santos <unixmania@gmail.com>
2019-10-15Fix value for O_mask_was_saved based on gdb observationmirabilos
(gdb) print offsetof(struct __jmp_buf_tag, __mask_was_saved) $12 = (int *) 0x1f0 using https://stackoverflow.com/a/39663128/2171120
2019-10-15sparc64: Make structure match kernel uapimirabilos
Update from linux/arch/sparc/include/uapi/asm/uctx.h
2019-10-15sparc64: Use the jmpbuf-offsets.h header instead of duplicating itmirabilos
2019-10-10aarch64: sync with glibc code to see any differences in a better wayWaldemar Brodkorb
2019-10-05or1k: Fix compiling with PIC and latest binutils use PLT for __syscall_errorStafford Horne
This symbol was causing a build failure with the new toolchain. It looks like it has always been wrong. The main issue was checking for PIC rather than __PIC__. Remove all PSEUDO_* macros and ther SYSCALL_ERROR_NAME macro as they are not needed by uclibc-ng, they are used in glibc for building up syscalls there, but not here. Fixes error: /opt/shorne/software/or1k-linux/bin/../lib/gcc/or1k-linux/9.0.1/../../../../or1k-linux/bin/ld: libc/libc_so.a(or1k_clone.os): pc-relative relocation against dynamic symbol __syscall_error /opt/shorne/software/or1k-linux/bin/../lib/gcc/or1k-linux/9.0.1/../../../../or1k-linux/bin/ld: final link failed: bad value Signed-off-by: Stafford Horne <shorne@gmail.com>
2019-09-30malloc: Add missing locks for some paths (valloc/memalign/posix_memalign)Kjetil Oftedal
The internal heap structures were not protected properly in memalign(). If multiple threads were concurrently allocating memory and one of them were requesting aligned memory via valloc,memalign or posix_memalign the internal heap data structures could be corrupted. Signed-off-by: Kjetil Oftedal <oftedal@gmail.com>
2019-09-30PowerPC: Fix termios definitionsAdhemerval Zanella
This patch fixes the incorrect guard by __USE_MISC of struct winsize and struct termio in powerpc termios header. Current states leads to build failures if the program defines _XOPEN_SOURCE, but not _DEFAULT_SOURCE or either _BSD_SOURCE or _SVID_SOURCE. Without any definition, __USE_MISC will not be defined and neither the struct definitions. This patch copies the default Linux ioctl-types.h by adjusting only the character control field (c_cc) size in struct termio. Signed-off-by: Vadim Kochan <vadim4j@gmail.com> [Vadim: adopted for uclibc ]
2019-07-05mips: avoid calling memcpy() from memmove() for MIPS archPetar Jovanovic
This is a follow up to an incorrect fix for memmove() problem in: commit 785dee78552f9ad06819bf7eb1adc05b43110842 Author: Petar Jovanovic <petar.jovanovic@rt-rk.com> Date: Mon May 6 13:29:02 2019 +0000 mips: fix memmove() call when __ARCH_HAS_BWD_MEMCPY__ is not defined Calling memcpy from memmove should be skipped in two cases: a) if arch's memcpy uses a backward copying (e.g. SH4) b) if arch's memcpy is not fully safe for overlapping regions (MIPS) Signed-off-by: Petar Jovanovic <petar.jovanovic@rt-rk.com>