Pull objtool updates from Ingo Molnar:
- Comprehensive interface overhaul:
=================================
Objtool's interface has some issues:
- Several features are done unconditionally, without any way to
turn them off. Some of them might be surprising. This makes
objtool tricky to use, and prevents porting individual features
to other arches.
- The config dependencies are too coarse-grained. Objtool
enablement is tied to CONFIG_STACK_VALIDATION, but it has several
other features independent of that.
- The objtool subcmds ("check" and "orc") are clumsy: "check" is
really a subset of "orc", so it has all the same options.
The subcmd model has never really worked for objtool, as it only
has a single purpose: "do some combination of things on an object
file".
- The '--lto' and '--vmlinux' options are nonsensical and have
surprising behavior.
Overhaul the interface:
- get rid of subcmds
- make all features individually selectable
- remove and/or clarify confusing/obsolete options
- update the documentation
- fix some bugs found along the way
- Fix x32 regression
- Fix Kbuild cleanup bugs
- Add scripts/objdump-func helper script to disassemble a single
function from an object file.
- Rewrite scripts/faddr2line to be section-aware, by basing it on
'readelf', moving it away from 'nm', which doesn't handle multiple
sections well, which can result in decoding failure.
- Rewrite & fix symbol handling - which had a number of bugs wrt.
object files that don't have global symbols - which is rare but
possible. Also fix a bunch of symbol handling bugs found along the
way.
* tag 'objtool-core-2022-05-23' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (23 commits)
objtool: Fix objtool regression on x32 systems
objtool: Fix symbol creation
scripts/faddr2line: Fix overlapping text section failures
scripts: Create objdump-func helper script
objtool: Remove libsubcmd.a when make clean
objtool: Remove inat-tables.c when make clean
objtool: Update documentation
objtool: Remove --lto and --vmlinux in favor of --link
objtool: Add HAVE_NOINSTR_VALIDATION
objtool: Rename "VMLINUX_VALIDATION" -> "NOINSTR_VALIDATION"
objtool: Make noinstr hacks optional
objtool: Make jump label hack optional
objtool: Make static call annotation optional
objtool: Make stack validation frame-pointer-specific
objtool: Add CONFIG_OBJTOOL
objtool: Extricate sls from stack validation
objtool: Rework ibt and extricate from stack validation
objtool: Make stack validation optional
objtool: Add option to print section addresses
objtool: Don't print parentheses in function addresses
...
Pull x86 asm updates from Borislav Petkov:
- A bunch of changes towards streamlining low level asm helpers'
calling conventions so that former can be converted to C eventually
- Simplify PUSH_AND_CLEAR_REGS so that it can be used at the system
call entry paths instead of having opencoded, slightly different
variants of it everywhere
- Misc other fixes
* tag 'x86_asm_for_v5.19_rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/entry: Fix register corruption in compat syscall
objtool: Fix STACK_FRAME_NON_STANDARD reloc type
linkage: Fix issue with missing symbol size
x86/entry: Remove skip_r11rcx
x86/entry: Use PUSH_AND_CLEAR_REGS for compat
x86/entry: Simplify entry_INT80_compat()
x86/mm: Simplify RESERVE_BRK()
x86/entry: Convert SWAPGS to swapgs and remove the definition of SWAPGS
x86/entry: Don't call error_entry() for XENPV
x86/entry: Move CLD to the start of the idtentry macro
x86/entry: Move PUSH_AND_CLEAR_REGS out of error_entry()
x86/entry: Switch the stack after error_entry() returns
x86/traps: Use pt_regs directly in fixup_bad_iret()
Pull nolibc library updates from Paul McKenney:
"This adds a number of library functions and splits this library into
multiple files"
* tag 'nolibc.2022.05.20a' of git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu: (61 commits)
tools/nolibc/string: Implement `strdup()` and `strndup()`
tools/nolibc/string: Implement `strnlen()`
tools/nolibc/stdlib: Implement `malloc()`, `calloc()`, `realloc()` and `free()`
tools/nolibc/types: Implement `offsetof()` and `container_of()` macro
tools/nolibc/sys: Implement `mmap()` and `munmap()`
tools/nolibc: i386: Implement syscall with 6 arguments
tools/nolibc: Remove .global _start from the entry point code
tools/nolibc: Replace `asm` with `__asm__`
tools/nolibc: x86-64: Update System V ABI document link
tools/nolibc/stdlib: only reference the external environ when inlined
tools/nolibc/string: do not use __builtin_strlen() at -O0
tools/nolibc: add the nolibc subdir to the common Makefile
tools/nolibc: add a makefile to install headers
tools/nolibc/types: add poll() and waitpid() flag definitions
tools/nolibc/sys: add syscall definition for getppid()
tools/nolibc/string: add strcmp() and strncmp()
tools/nolibc/stdio: add support for '%p' to vfprintf()
tools/nolibc/stdlib: add a simple getenv() implementation
tools/nolibc/stdio: make printf(%s) accept NULL
tools/nolibc/stdlib: implement abort()
...
To pick the changes in:
d495f942f4 ("KVM: fix bad user ABI for KVM_EXIT_SYSTEM_EVENT")
That just rebuilds perf, as these patches don't add any new KVM ioctl to
be harvested for the the 'perf trace' ioctl syscall argument
beautifiers.
This is also by now used by tools/testing/selftests/kvm/, a simple test
build succeeded.
This silences this perf build warning:
Warning: Kernel ABI header at 'tools/include/uapi/linux/kvm.h' differs from latest version at 'include/uapi/linux/kvm.h'
diff -u tools/include/uapi/linux/kvm.h include/uapi/linux/kvm.h
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Link: http://lore.kernel.org/lkml/YnE5BIweGmCkpOTN@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Turn kmem_cache_alloc() into a wrapper around kmem_cache_alloc_lru().
Fixes: 9bbdc0f324 ("xarray: use kmem_cache_alloc_lru to allocate xa_node")
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reported-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Reported-by: Li Wang <liwang@redhat.com>
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>
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>
raise() doesn't set errno, so there's no point calling kill(), better
call sys_kill(), which also reduces the function's size.
Signed-off-by: Willy Tarreau <w@1wt.eu>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
The build of printf() on mips requires libgcc for functions __ashldi3 and
__lshrdi3 due to 64-bit shifts when scanning the input number. These are
not really needed in fact since we scan the number 4 bits at a time. Let's
arrange the loop to perform two 32-bit shifts instead on 32-bit platforms.
Signed-off-by: Willy Tarreau <w@1wt.eu>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Let's pass a vararg to open() so that it remains compatible with existing
code. The arg is only dereferenced when flags contain O_CREAT. The function
is generally not inlined anymore, causing an extra call (total 16 extra
bytes) but it's still optimized for constant propagation, limiting the
excess to no more than 16 bytes in practice when open() is called without
O_CREAT, and ~40 with O_CREAT, which remains reasonable.
Signed-off-by: Willy Tarreau <w@1wt.eu>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
It doesn't contain the text for the error codes, but instead displays
"errno=" followed by the errno value. Just like the regular errno, if
a non-empty message is passed, it's placed followed with ": " on the
output before the errno code. The message is emitted on stderr.
Signed-off-by: Willy Tarreau <w@1wt.eu>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
These ones are found in some examples found in man pages and ease
portability tests.
Signed-off-by: Willy Tarreau <w@1wt.eu>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
This adds a minimal vfprintf() implementation as well as the commonly
used fprintf() and printf() that rely on it.
For now the function supports:
- formats: %s, %c, %u, %d, %x
- modifiers: %l and %ll
- unknown chars are considered as modifiers and are ignored
It is designed to remain minimalist, despite this printf() is 549 bytes
on x86_64. It would be wise not to add too many formats.
Signed-off-by: Willy Tarreau <w@1wt.eu>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
We'll use it to write substrings. It relies on a simpler _fwrite() that
only takes one size. fputs() was also modified to rely on it.
Signed-off-by: Willy Tarreau <w@1wt.eu>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
The standard puts() function always emits the trailing LF which makes it
unconvenient for small string concatenation. fputs() ought to be used
instead but it requires a FILE*.
This adds 3 dummy FILE* values (stdin, stdout, stderr) which are in fact
pointers to struct FILE of one byte. We reserve 3 pointer values for them,
-3, -2 and -1, so that they are ordered, easing the tests and mapping to
integer.
>From this, fgetc(), fputc(), fgets() and fputs() were implemented, and
the previous putchar() and getchar() now remap to these. The standard
getc() and putc() macros were also implemented as pointing to these
ones.
There is absolutely no buffering, fgetc() and fgets() read one byte at
a time, fputc() writes one byte at a time, and only fputs() which knows
the string's length writes all of it at once.
Signed-off-by: Willy Tarreau <w@1wt.eu>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
