From Jan Engelhardt:
Program received signal SIGBUS, Bus error.
[Switching to process 11100]
0x00035278 in kmod_module_signature_info (file=0x4eeb8, sig_info=0xffffc254)
at libkmod/libkmod-signature.c:124
124 sig_len = be32toh(modsig->sig_len);
(gdb) p modsig
$1 = (const struct module_signature *) 0xf7dfe143
modsig->sig_len can be unaligned if modsig is unaligned, so the padding
in the struct has no effect since we are mapping it to the mem buffer.
Commit 51c409b ("Cache the offset of crc") unintentinally changed the
comparison "if (elf->class & KMOD_ELF_32)" to
"if (elf->class == KMOD_ELF_32)".
This has been reported by Serge Voilokov <serge0x76@gmail.com>:
On Raspberry PI elf->class equals KMOD_ELF_32|KMOD_ELF_LSB so
valid condition should be (elf->class & KMOD_ELF_32) instead of
(elf->class == KMOD_ELF_32).
This fixes "modprobe --dump-modversions" failing on 32b systems.
These redirecting makefiles simplifies compiling from some editors and
when CWD is not the root of the source tree. This is similar to what was
introduced in systemd in 340d89e ("build-sys: add small redirecting
Makefiles to simplify compilation from within emacs")
Otherwise, we also parse strings like
BOOT_IMAGE=/boot/vmlinuz-3.12.12-57.g5f654cf-default
In practice, this is not a problem, because there is no module named
BOOT_IMAGE=/boot/vmlinuz-3. It just disturbs in modprobe -c output.
If we can open it and read it, it's good enough for us. Otherwise, we
cannot use -C /dev/null to skip the system configuration for instance:
$ ./tools/modprobe -C /dev/null -c
libkmod: ERROR libkmod/libkmod-config.c:821 conf_files_list: unsupported
file mode /dev/null: 0x21b6
...
Also define noreturn w/o <stdnoreturn.h> and move it to macro.h instead
of in the testsuite.
Based on similar commit on systemd by Shawn Landden
<shawn@churchofgit.com>.
By aligning n_buckets to power of 2 we can turn the "bucket = hashval %
n_buckets" into a less expensive bucket = hashval & (n_buckets - 1).
This removes the DIV instruction as shown below.
Before:
xor %edx,%edx
divl 0x8(%rbx)
mov %edx,%eax
add $0x1,%rax
shl $0x4,%rax
add %rbx,%rax
After:
lea -0x1(%rdi),%edx
and %edx,%eax
add $0x1,%rax
shl $0x4,%rax
add %rbx,%rax
With a microbenchmark, measuring the time to locate the bucket (i.e.
time_to_calculate_hashval + time_to_calculate_bucket_position) we have
the results below (time in clock cycles):
keylen before after
2-10 79.0 61.9 (-21.65%)
11-17 81.0 64.4 (-20.48%)
18-25 90.0 73.2 (-18.69%)
26-32 104.7 87.0 (-16.82%)
33-40 108.4 89.6 (-17.37%)
41-48 111.2 91.9 (-17.38%)
49-55 120.1 102.1 (-15.04%)
56-63 134.4 115.7 (-13.91%)
As expected the gain is constant, regardless of the key length.
The time to clculate the hashval varies with the key length, which
explains the bigger gains for short keys.
Add static inline function to align a value to it's next power of 2.
This is commonly done by a SWAR like the one in:
http://aggregate.org/MAGIC/#Next Largest Power of 2
However a microbench shows that the implementation herer is a faster.
It doesn't really impact the possible user of this function, but it's
interesting nonetheless.
Using a x86_64 i7 Ivy Bridge it shows a ~4% advantage by using clz
instead instead of the OR and SHL chain. And this is by using a BSR
since Ivy Bridge doesn't have LZCNT. New Haswell processors have the
LZCNT instruction which can make this even better. ARM also has a CLZ
instruction so it should be better, too.
Code used to test:
...
v = val[i];
t1 = get_cycles(0);
a = ALIGN_POWER2(v);
t1 = get_cycles(t1);
t2 = get_cycles(0);
v = nlpo2(v);
t2 = get_cycles(t2);
printf("%u\t%llu\t%llu\t%d\n", v, t1, t2, v == a);
...
In which val is an array of 20 random unsigned int, nlop2 is the SWAR
implementation and get_cycles uses RDTSC to measure the performance.
Averages:
ALIGN_POWER2: 30 cycles
nlop2: 31.4 cycles
It's used in so many places without checking, that's really pointless to
check for it in macro.h.
Also remove AC_C_TYPEOF from configure.ac since we don't use -ansi.
Commit 8efede20ef ("Use _Static_assert") introduced the usage of
_Static_assert(). However, _Static_assert() is a fairly new thing,
since it was introduced only in gcc 4.6. In order to support older
compilers, this patch adds a configure.in test that checks whether
_Static_assert() is usable or not, and adjust the behavior of the
assert_cc() macro accordingly.
With readdir_r() we should be providing enough space to store the dir
name. This could be accomplished by define an union like systemd does:
union dirent_storage {
struct dirent de;
uint8_t storage[offsetof(struct dirent, d_name) +
((NAME_MAX + 1 + sizeof(long)) & ~(sizeof(long) - 1))];
};
However in all places that we use readdir_r() we have no concerns about
reentrance nor we have problems with threads. Thus use the simpler
readdir() instead.
We also remove the error logging here (that could be added back by
checking errno), but it was not adding much value so it's gone.
It occurred to an openSUSE user that our mkinitrd would throw a
warning when used with kmod:
libkmod: conf_files_list: unsupported file mode /dev/null: 0x21b6
Grepping for the error message revealed that there might be a missing
"else" keyword here, since it is unusual to put an "if" directly after
closing brace.
At least in qemu 1.4.1 for vexpress/arm-cortexa9, this resulted in an
illegal instruction error. Solve that by returning an error when
__NR_finit_module is -1.
This reverts commit 38829712e5. It fixes
the problem, but it breaks the testsuite for those who don't have
__NR_finit_module. The testsuite would have to make the same check.
Instead, I'm reverting this change and I'm going to apply another patch
from Jan Luebbe who got this right from the beginning.
There are several exported enums by libkmod without document, this patch
mainly added documentation for below enums like the way kmod_resources
be documented in.
* kmod_index
* kmod_remove
* kmod_insert
* kmod_probe
* kmod_filter
* kmod_module_initstate
This is not the best way to document these exported enums, however, it's
the simple way due to gtkdoc limits. It doesn't support export plain
enum like below: see https://bugzilla.gnome.org/show_bug.cgi?id=657444
---------8<-------head.h--------------8<-----------
...
enum foo {
...
};
...
---------8<-------end of head.h-------8<-----------
---------8<-------source.c------------8<-----------
...
/**
* document for foo here
*/
...
typedef enum foo foo;
...
---------8<-------end of source.c-----8<----------
Add __attribute__((format)) to log_filep() and _show() functions, fixing
the bugs they found in the source code.
For functions that receive va_list instead of being variadic functions
we put 0 in the last argument, so at least the string is checked and we
get warnings of -Wformat-nonliteral type. So, it's better than adding a
pragma here to shut up the warning.
Check for finit_module() and don't use our own static inline function if
there's such function in libc (or another lib).
In testsuite we need to unconditionally define HAVE_FINIT_MODULE because
we want to override this function, and never use the static inline one
in missing.h
