When RISCV port was imported in 5.2, the O_* macros were taken with
their octal value and written as-is in hex, resulting in the getdents64()
to fail in nolibc-test.
Fixes: 582e84f7b7 ("tool headers nolibc: add RISCV support") #5.2
Signed-off-by: Willy Tarreau <w@1wt.eu>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
When building on ARM in thumb mode with gcc-11.3 at -O2 or -O3,
nolibc-test segfaults during the select() tests. It turns out that at
this level, gcc recognizes an opportunity for using memset() to zero
the fd_set, but it miscompiles it because it also recognizes a memset
pattern as well, and decides to call memset() from the memset() code:
000122bc <memset>:
122bc: b510 push {r4, lr}
122be: 0004 movs r4, r0
122c0: 2a00 cmp r2, #0
122c2: d003 beq.n 122cc <memset+0x10>
122c4: 23ff movs r3, #255 ; 0xff
122c6: 4019 ands r1, r3
122c8: f7ff fff8 bl 122bc <memset>
122cc: 0020 movs r0, r4
122ce: bd10 pop {r4, pc}
Simply placing an empty asm() statement inside the loop suffices to
avoid this.
Signed-off-by: Willy Tarreau <w@1wt.eu>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
After the nolibc includes were split to facilitate portability from
standard libcs, programs that include only what they need may miss
some symbols which are needed by libgcc. This is the case for raise()
which is needed by the divide by zero code in some architectures for
example.
Regardless, being able to include only the apparently needed files is
convenient.
Instead of trying to move all exported definitions to a single file,
since this can change over time, this patch takes another approach
consisting in including the nolibc header at the end of all standard
include files. This way their types and functions are already known
at the moment of inclusion, and including any single one of them is
sufficient to bring all the required ones.
Signed-off-by: Willy Tarreau <w@1wt.eu>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Depending on the compiler used and the optimization options, the sbrk()
test was crashing, both on real hardware (mips-24kc) and in qemu. One
such example is kernel.org toolchain in version 11.3 optimizing at -Os.
Inspecting the sys_brk() call shows the following code:
0040047c <sys_brk>:
40047c: 24020fcd li v0,4045
400480: 27bdffe0 addiu sp,sp,-32
400484: 0000000c syscall
400488: 27bd0020 addiu sp,sp,32
40048c: 10e00001 beqz a3,400494 <sys_brk+0x18>
400490: 00021023 negu v0,v0
400494: 03e00008 jr ra
It is obviously wrong, the "negu" instruction is placed in beqz's
delayed slot, and worse, there's no nop nor instruction after the
return, so the next function's first instruction (addiu sip,sip,-32)
will also be executed as part of the delayed slot that follows the
return.
This is caused by the ".set noreorder" directive in the _start block,
that applies to the whole program. The compiler emits code without the
delayed slots and relies on the compiler to swap instructions when this
option is not set. Removing the option would require to change the
startup code in a way that wouldn't make it look like the resulting
code, which would not be easy to debug. Instead let's just save the
default ordering before changing it, and restore it at the end of the
_start block. Now the code is correct:
0040047c <sys_brk>:
40047c: 24020fcd li v0,4045
400480: 27bdffe0 addiu sp,sp,-32
400484: 0000000c syscall
400488: 10e00002 beqz a3,400494 <sys_brk+0x18>
40048c: 27bd0020 addiu sp,sp,32
400490: 00021023 negu v0,v0
400494: 03e00008 jr ra
400498: 00000000 nop
Fixes: 66b6f755ad ("rcutorture: Import a copy of nolibc") #5.0
Signed-off-by: Willy Tarreau <w@1wt.eu>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
The mode field has the type encoded as an value in a field, not as a bit
mask. Mask the mode with S_IFMT instead of each type to test. Otherwise,
false positives are possible: eg S_ISDIR will return true for block
devices because S_IFDIR = 0040000 and S_IFBLK = 0060000 since mode is
masked with S_IFDIR instead of S_IFMT. These macros now match the
similar definitions in tools/include/uapi/linux/stat.h.
Signed-off-by: Warner Losh <imp@bsdimp.com>
Signed-off-by: Willy Tarreau <w@1wt.eu>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
The kernel uses unsigned long for the fd_set bitmap,
but nolibc use u32. This works fine on little endian
machines, but fails on big endian. Convert to unsigned
long to fix this.
Signed-off-by: Sven Schnelle <svens@linux.ibm.com>
Signed-off-by: Willy Tarreau <w@1wt.eu>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
The C standard says that memcmp() must treat the buffers as consisting
of "unsigned chars". If char happens to be unsigned, the casts are ok,
but then obviously the c1 variable can never contain a negative
value. And when char is signed, the casts are wrong, and there's still
a problem with using an 8-bit quantity to hold the difference, because
that can range from -255 to +255.
For example, assuming char is signed, comparing two 1-byte buffers,
one containing 0x00 and another 0x80, the current implementation would
return -128 for both memcmp(a, b, 1) and memcmp(b, a, 1), whereas one
of those should of course return something positive.
Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Fixes: 66b6f755ad ("rcutorture: Import a copy of nolibc")
Cc: stable@vger.kernel.org # v5.0+
Signed-off-by: Willy Tarreau <w@1wt.eu>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
When built at -Os, gcc-12 recognizes an strlen() pattern in nolibc_strlen()
and replaces it with a jump to strlen(), which is not defined as a symbol
and breaks compilation. Worse, when the function is called strlen(), the
function is simply replaced with a jump to itself, hence becomes an
infinite loop.
One way to avoid this is to always set -ffreestanding, but the calling
code doesn't know this and there's no way (either via attributes or
pragmas) to globally enable it from include files, effectively leaving
a painful situation for the caller.
Alexey suggested to place an empty asm() statement inside the loop to
stop gcc from recognizing a well-known pattern, which happens to work
pretty fine. At least it allows us to make sure our local definition
is not replaced with a self jump.
The function only needs to be renamed back to strlen() so that the symbol
exists, which implies that nolibc_strlen() which is used on variable
strings has to be declared as a macro that points back to it before the
strlen() macro is redifined.
It was verified to produce valid code with gcc 3.4 to 12.1 at different
optimization levels, and both with constant and variable strings.
In case this problem surfaces again in the future, an alternate approach
consisting in adding an optimize("no-tree-loop-distribute-patterns")
function attribute for gcc>=12 worked as well but is less pretty.
Reported-by: kernel test robot <yujie.liu@intel.com>
Link: https://lore.kernel.org/r/202210081618.754a77db-yujie.liu@intel.com
Fixes: 66b6f755ad ("rcutorture: Import a copy of nolibc")
Fixes: 96980b833a ("tools/nolibc/string: do not use __builtin_strlen() at -O0")
Cc: "Paul E. McKenney" <paulmck@kernel.org>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Willy Tarreau <w@1wt.eu>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
__NR_mmap2 was used for i386 but it's also needed for other archs such
as RISCV32 or ARM. Let's decide to use it based on the __NR_mmap2
definition as it's not defined on other archs.
Signed-off-by: Willy Tarreau <w@1wt.eu>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
We return -ENOSYS when there's no syscall6() operation, but we must cast
it to void* to avoid a warning.
Signed-off-by: Willy Tarreau <w@1wt.eu>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
The "ld a0, 0(sp)" instruction doesn't build on RISCV32 because that
would load a 64-bit value into a 32-bit register. But argc 32-bit,
not 64, so we ought to use "lw" here. Tested on both RISCV32 and
RISCV64.
Cc: Pranith Kumar <bobby.prani@gmail.com>
Signed-off-by: Willy Tarreau <w@1wt.eu>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
The "help" target simply presents the list of supported targets
and the current set of variables being used to build the sysroot.
Since the help in tools/ suggests to use "install", which is
supported by most tools while such a target is not really relevant
here, an "install" target was also added, redirecting to "help".
Signed-off-by: Willy Tarreau <w@1wt.eu>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
The help in "make -C tools" enumerates nolibc as a valid target so we
must at least make it do something. Let's make it do the equivalent
of "make headers" in that it will prepare a sysroot with the arch's
headers, but will not install the kernel's headers. This is the
minimum some tools will need when built with a full-blown toolchain
anyway.
Signed-off-by: Willy Tarreau <w@1wt.eu>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
As reported by Linus, the nolibc's makefile is currently broken when
invoked as per the documented method (make -C tools nolibc_<target>),
because it now relies on the ARCH and OUTPUT variables that are not
set in this case.
This patch addresses this by sourcing subarch.include, and by
presetting OUTPUT to the current directory if not set. This is
sufficient to make the commands work both as a standalone target
and as a tools/ sub-target.
Signed-off-by: Willy Tarreau <w@1wt.eu>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
When we use printf and fprintf functions from the nolibc, we don't
get any warning from the compiler if we have the wrong arguments.
For example, the following calls will compile silently:
```
printf("%s %s\n", "aaa");
fprintf(stdout, "%s %s\n", "xxx", 1);
```
(Note the wrong arguments).
Those calls are undefined behavior. The compiler can help us warn
about the above mistakes by adding a `printf` format attribute to
those functions declaration. This patch adds it, and now it yields
these warnings for those mistakes:
```
warning: format `%s` expects a matching `char *` argument [-Wformat=]
warning: format `%s` expects argument of type `char *`, but argument 4 has type `int` [-Wformat=]
```
[ ammarfaizi2: Simplify the attribute placement. ]
Signed-off-by: Alviro Iskandar Setiawan <alviro.iskandar@gnuweeb.org>
Signed-off-by: Ammar Faizi <ammarfaizi2@gnuweeb.org>
Acked-by: Willy Tarreau <w@1wt.eu>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Previously, we used __builtin_mul_overflow() to check for overflow in
the multiplication operation in the calloc() function. However, older
compiler versions don't support this built-in. This patch changes the
overflow checking mechanism to make it work on any compiler version
by using a division method to check for overflow. No functional change
intended. While in there, remove the unused variable `void *orig`.
Link: https://lore.kernel.org/lkml/20220330024114.GA18892@1wt.eu
Suggested-by: Willy Tarreau <w@1wt.eu>
Cc: Alviro Iskandar Setiawan <alviro.iskandar@gnuweeb.org>
Signed-off-by: Ammar Faizi <ammarfaizi2@gnuweeb.org>
Acked-by: Willy Tarreau <w@1wt.eu>
Reviewed-by: Alviro Iskandar Setiawan <alviro.iskandar@gnuweeb.org>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
These functions are currently only available on architectures that have
my_syscall6() macro implemented. Since these functions use malloc(),
malloc() uses mmap(), mmap() depends on my_syscall6() macro.
On architectures that don't support my_syscall6(), these function will
always return NULL with errno set to ENOSYS.
Acked-by: Willy Tarreau <w@1wt.eu>
Signed-off-by: Ammar Faizi <ammarfaizi2@gnuweeb.org>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
size_t strnlen(const char *str, size_t maxlen);
The strnlen() function returns the number of bytes in the string
pointed to by sstr, excluding the terminating null byte ('\0'), but at
most maxlen. In doing this, strnlen() looks only at the first maxlen
characters in the string pointed to by str and never beyond str[maxlen-1].
The first use case of this function is for determining the memory
allocation size in the strndup() function.
Link: https://lore.kernel.org/lkml/CAOG64qMpEMh+EkOfjNdAoueC+uQyT2Uv3689_sOr37-JxdJf4g@mail.gmail.com
Suggested-by: Alviro Iskandar Setiawan <alviro.iskandar@gnuweeb.org>
Acked-by: Willy Tarreau <w@1wt.eu>
Signed-off-by: Ammar Faizi <ammarfaizi2@gnuweeb.org>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Implement basic dynamic allocator functions. These functions are
currently only available on architectures that have nolibc mmap()
syscall implemented. These are not a super-fast memory allocator,
but at least they can satisfy basic needs for having heap without
libc.
Cc: David Laight <David.Laight@ACULAB.COM>
Acked-by: Willy Tarreau <w@1wt.eu>
Signed-off-by: Ammar Faizi <ammarfaizi2@gnuweeb.org>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Implement `offsetof()` and `container_of()` macro. The first use case
of these macros is for `malloc()`, `realloc()` and `free()`.
Acked-by: Willy Tarreau <w@1wt.eu>
Signed-off-by: Ammar Faizi <ammarfaizi2@gnuweeb.org>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Implement mmap() and munmap(). Currently, they are only available for
architecures that have my_syscall6 macro. For architectures that don't
have, this function will return -1 with errno set to ENOSYS (Function
not implemented).
This has been tested on x86 and i386.
Notes for i386:
1) The common mmap() syscall implementation uses __NR_mmap2 instead
of __NR_mmap.
2) The offset must be shifted-right by 12-bit.
Acked-by: Willy Tarreau <w@1wt.eu>
Signed-off-by: Ammar Faizi <ammarfaizi2@gnuweeb.org>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
On i386, the 6th argument of syscall goes in %ebp. However, both Clang
and GCC cannot use %ebp in the clobber list and in the "r" constraint
without using -fomit-frame-pointer. To make it always available for
any kind of compilation, the below workaround is implemented.
1) Push the 6-th argument.
2) Push %ebp.
3) Load the 6-th argument from 4(%esp) to %ebp.
4) Do the syscall (int $0x80).
5) Pop %ebp (restore the old value of %ebp).
6) Add %esp by 4 (undo the stack pointer).
Cc: x86@kernel.org
Cc: llvm@lists.linux.dev
Link: https://lore.kernel.org/lkml/2e335ac54db44f1d8496583d97f9dab0@AcuMS.aculab.com
Suggested-by: David Laight <David.Laight@ACULAB.COM>
Acked-by: Willy Tarreau <w@1wt.eu>
Signed-off-by: Ammar Faizi <ammarfaizi2@gnuweeb.org>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Building with clang yields the following error:
```
<inline asm>:3:1: error: _start changed binding to STB_GLOBAL
.global _start
^
1 error generated.
```
Make sure only specify one between `.global _start` and `.weak _start`.
Remove `.global _start`.
Cc: llvm@lists.linux.dev
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Acked-by: Willy Tarreau <w@1wt.eu>
Signed-off-by: Ammar Faizi <ammarfaizi2@gnuweeb.org>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Replace `asm` with `__asm__` to support compilation with -std flag.
Using `asm` with -std flag makes GCC think `asm()` is a function call
instead of an inline assembly.
GCC doc says:
For the C language, the `asm` keyword is a GNU extension. When
writing C code that can be compiled with `-ansi` and the `-std`
options that select C dialects without GNU extensions, use
`__asm__` instead of `asm`.
Link: https://gcc.gnu.org/onlinedocs/gcc/Basic-Asm.html
Reported-by: Alviro Iskandar Setiawan <alviro.iskandar@gnuweeb.org>
Acked-by: Willy Tarreau <w@1wt.eu>
Signed-off-by: Ammar Faizi <ammarfaizi2@gnuweeb.org>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
The old link no longer works, update it.
Acked-by: Willy Tarreau <w@1wt.eu>
Signed-off-by: Ammar Faizi <ammarfaizi2@gnuweeb.org>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
When building with gcc at -O0 we're seeing link errors due to the
"environ" variable being referenced by getenv(). The problem is that
at -O0 gcc will not inline getenv() and will not drop the external
reference. One solution would be to locally declare the variable as
weak, but then it would appear in all programs even those not using
it, and would be confusing to users of getenv() who would forget to
set environ to envp.
An alternate approach used in this patch consists in always inlining
the outer part of getenv() that references this extern so that it's
always dropped when not used. The biggest part of the function was
now moved to a new function called _getenv() that's still not inlined
by default.
Reported-by: Ammar Faizi <ammarfaizi2@gnuweeb.org>
Signed-off-by: Willy Tarreau <w@1wt.eu>
Tested-by: Ammar Faizi <ammarfaizi2@gnuweeb.org>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
clang wants to use strlen() for __builtin_strlen() at -O0. We don't
really care about -O0 but it at least ought to build, so let's make
sure we don't choke on this, by dropping the optimizationn for
constant strings in this case.
Signed-off-by: Willy Tarreau <w@1wt.eu>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
This provides a target "headers_standalone" which installs the nolibc's
arch-specific headers with "arch.h" taken from the current arch (or a
concatenation of both i386 and x86_64 for arch=x86), then installs
kernel headers. This creates a convenient sysroot which is directly
usable by a bare-metal compiler to create any executable.
Signed-off-by: Willy Tarreau <w@1wt.eu>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
- POLLIN etc were missing, so poll() could only be used with timeouts.
- WNOHANG was not defined and is convenient to check if a child is still
running
Signed-off-by: Willy Tarreau <w@1wt.eu>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
This is essentially for completeness as it's not the most often used
in regtests.
Signed-off-by: Willy Tarreau <w@1wt.eu>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
We need these functions all the time, including when checking environment
variables and parsing command-line arguments. These implementations were
optimized to show optimal code size on a wide range of compilers (22 bytes
return included for strcmp(), 33 for strncmp()).
Signed-off-by: Willy Tarreau <w@1wt.eu>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
%p remains quite useful in test code, and the code path can easily be
merged with the existing "%x" thus only adds ~50 bytes, thus let's
add it.
Signed-off-by: Willy Tarreau <w@1wt.eu>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
This implementation relies on an extern definition of the environ
variable, that the caller must declare and initialize from envp.
Signed-off-by: Willy Tarreau <w@1wt.eu>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
It's often convenient to support this, especially in test programs where
a NULL may correspond to an allocation error or a non-existing value.
Let's make printf("%s") support being passed a NULL. In this case it
prints "(null)" like glibc's printf().
Signed-off-by: Willy Tarreau <w@1wt.eu>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
libgcc uses it for certain divide functions, so it must be exported. Like
for memset() we do that in its own section so that the linker can strip
it when not needed.
Signed-off-by: Willy Tarreau <w@1wt.eu>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Now that a few basic include files are provided, some simple portable
programs may build, which will save them from having to surround their
includes with #ifndef NOLIBC. This patch mentions how to proceed, and
enumerates the list of files that are covered.
A comprehensive list of required include files is available here:
https://en.cppreference.com/w/c/header
Signed-off-by: Willy Tarreau <w@1wt.eu>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
The time() syscall is used by a few simple applications, and is trivial
to implement based on gettimeofday() that we already have. Let's create
the file to ease porting and provide the function. It never returns any
error, though it may segfault in case of invalid pointer, like other
implementations relying on gettimeofday().
Signed-off-by: Willy Tarreau <w@1wt.eu>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
This function is normally found in signal.h, and providing the file
eases porting of existing programs. Let's move it there.
Signed-off-by: Willy Tarreau <w@1wt.eu>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
This call is trivial to implement based on select() to complete sleep()
and msleep(), let's add it.
Signed-off-by: Willy Tarreau <w@1wt.eu>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
These functions are normally provided by unistd.h. For ease of porting,
let's create the file and move them there.
Signed-off-by: Willy Tarreau <w@1wt.eu>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
This allows us to provide a minimal errno.h to ease porting applications
that use it.
Signed-off-by: Willy Tarreau <w@1wt.eu>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
"clang -Os" and "gcc -Ofast" without -ffreestanding may ignore memset()
and memmove(), hoping to provide their builtin equivalents, and finally
not find them. Thus we must export these functions for these rare cases.
Note that as they're set in their own sections, they will be eliminated
by the linker if not used. In addition, they do not prevent gcc from
identifying them and replacing them with the shorter "rep movsb" or
"rep stosb" when relevant.
Signed-off-by: Willy Tarreau <w@1wt.eu>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
These ones are often used and commonly set by applications to fallback
values. Let's fix them both to agree on PATH_MAX=4096 by default, as is
already present in linux/limits.h.
Signed-off-by: Willy Tarreau <w@1wt.eu>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
By doing so we can link together multiple C files that have been compiled
with nolibc and which each have a _start symbol.
Signed-off-by: Willy Tarreau <w@1wt.eu>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Some functions like raise() and memcpy() are permanently exported because
they're needed by libgcc on certain platforms. However most of the time
they are not needed and needlessly take space.
Let's move them to their own sub-section, called .text.nolibc_<function>.
This allows ld to get rid of them if unused when passed --gc-sections.
Signed-off-by: Willy Tarreau <w@1wt.eu>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
While these functions are often dangerous, forcing the user to work
around their absence is often much worse. Let's provide small versions
of each of them. The respective sizes in bytes on a few architectures
are:
strncat(): x86:0x33 mips:0x68 arm:0x3c
strlcat(): x86:0x25 mips:0x4c arm:0x2c
The two are quite different, and strncat() is even different from
strncpy() in that it limits the amount of data it copies and will always
terminate the output by one zero, while strlcat() will always limit the
total output to the specified size and will put a zero if possible.
Signed-off-by: Willy Tarreau <w@1wt.eu>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
These are minimal variants. strncpy() always fills the destination for
<size> chars, while strlcpy() copies no more than <size> including the
zero and returns the source's length. The respective sizes on various
archs are:
strncpy(): x86:0x1f mips:0x30 arm:0x20
strlcpy(): x86:0x17 mips:0x34 arm:0x1a
Signed-off-by: Willy Tarreau <w@1wt.eu>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
The direction test inside the loop was not always completely optimized,
resulting in a larger than necessary function. This change adds a
direction variable that is set out of the loop. Now the function is down
to 48 bytes on x86, 32 on ARM and 68 on mips. It's worth noting that other
approaches were attempted (including relying on the up and down functions)
but they were only slightly beneficial on x86 and cost more on others.
Signed-off-by: Willy Tarreau <w@1wt.eu>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Till now memcpy() relies on memmove(), but it's always included for libgcc,
so we have a larger than needed function. Let's implement two unidirectional
variants to copy from bottom to top and from top to bottom, and use the
former for memcpy(). The variants are optimized to be compact, and at the
same time the compiler is sometimes able to detect the loop and to replace
it with a "rep movsb". The new function is 24 bytes instead of 52 on x86_64.
Signed-off-by: Willy Tarreau <w@1wt.eu>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
These syscalls never fail so there is no need to extract and set errno
for them.
Signed-off-by: Willy Tarreau <w@1wt.eu>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
