Ulrich Weigand [Wed, 4 Dec 2013 12:52:40 +0000 (06:52 -0600)]
PowerPC64 ELFv2 ABI 3/6: PLT local entry point optimization
This is a follow-on to the previous patch to support the ELFv2 ABI in the
dynamic loader, split off into its own patch since it is just an optional
optimization.
In the ELFv2 ABI, most functions define both a global and a local entry
point; the local entry requires r2 to be already set up by the caller
to point to the callee's TOC; while the global entry does not require
the caller to know about the callee's TOC, but it needs to set up r12
to the callee's entry point address.
Now, when setting up a PLT slot, the dynamic linker will usually need
to enter the target function's global entry point. However, if the
linker can prove that the target function is in the same DSO as the
PLT slot itself, and the whole DSO only uses a single TOC (which the
linker will let ld.so know via a DT_PPC64_OPT entry), then it is
possible to actually enter the local entry point address into the
PLT slot, for a slight improvement in performance.
Note that this uncovered a problem on the first call via _dl_runtime_resolve,
because that routine neglected to restore the caller's TOC before calling
the target function for the first time, since it assumed that function
would always reload its own TOC anyway ...
Ulrich Weigand [Wed, 4 Dec 2013 12:51:11 +0000 (06:51 -0600)]
PowerPC64 ELFv2 ABI 2/6: Remove function descriptors
This patch adds support for the ELFv2 ABI feature to remove function
descriptors. See this GCC patch for in-depth discussion:
http://gcc.gnu.org/ml/gcc-patches/2013-11/msg01141.html
This mostly involves two types of changes: updating assembler source
files to the new logic, and updating the dynamic loader.
After the refactoring in the previous patch, most of the assembler source
changes can be handled simply by providing ELFv2 versions of the
macros in sysdep.h. One somewhat non-obvious change is in __GI__setjmp:
this used to "fall through" to the immediately following __setjmp ENTRY
point. This is no longer safe in the ELFv2 since ENTRY defines both
a global and a local entry point, and you cannot simply fall through
to a global entry point as it requires r12 to be set up.
Also, makecontext needs to be updated to set up registers according to
the new ABI for calling into the context's start routine.
The dynamic linker changes mostly consist of removing special code
to handle function descriptors. We also need to support the new PLT
and glink format used by the the ELFv2 linker, see:
https://sourceware.org/ml/binutils/2013-10/msg00376.html
In addition, the dynamic linker now verifies that the dynamic libraries
it loads match its own ABI.
The hack in VDSO_IFUNC_RET to "synthesize" a function descriptor
for vDSO routines is also no longer necessary for ELFv2.
Ulrich Weigand [Wed, 4 Dec 2013 12:49:15 +0000 (06:49 -0600)]
PowerPC64 ELFv2 ABI 1/6: Code refactoring
This is the first patch to support the new ELFv2 ABI in glibc.
As preparation, this patch simply refactors some of the powerpc64 assembler
code to move all code related to creating function descriptors (.opd section)
or using function descriptors (function pointer call) into a central place
in sysdep.h.
Note that most locations creating .opd entries were already using macros
in sysdep.h, this patch simply extends this to the remaining places.
Ulrich Weigand [Wed, 4 Dec 2013 12:45:56 +0000 (06:45 -0600)]
PowerPC64: Add __private_ss field to TCB header
The TCB header on Intel contains a field __private_ss that is used
to efficiently implement the -fsplit-stack GCC feature.
In order to prepare for a possible future implementation of that
feature on powerpc64, we'd like to reserve a similar field in
the TCB header as well. (It would be good if this went in with
or before the ELFv2 patches to ensure that this field will be
available always in the ELFv2 environment.)
The field needs to be added at the front of tcbhead_t structure
to avoid changing the ABI; see the recent discussion when adding
the EBB fields.
Alan Modra [Wed, 4 Dec 2013 12:44:06 +0000 (06:44 -0600)]
PowerPC64: Report overflow on @h and @ha relocations
This patch updates glibc in accordance with the binutils patch checked in here:
https://sourceware.org/ml/binutils/2013-10/msg00372.html
This changes the various R_PPC64_..._HI and _HA relocations to report
32-bit overflows. The motivation is that existing uses of @h / @ha
are to build up 32-bit offsets (for the "medium model" TOC access
that GCC now defaults to), and we'd really like to see failures at
link / load time rather than silent truncations.
For those rare cases where a modifier is needed to build up a 64-bit
constant, new relocations _HIGH / _HIGHA are supported.
The patch also fixes a bug in overflow checking for the R_PPC64_ADDR30
and R_PPC64_ADDR32 relocations.
Ulrich Weigand [Wed, 4 Dec 2013 12:41:52 +0000 (06:41 -0600)]
PowerPC64: Fix incorrect CFI in *context routines
The context established by "makecontext" has a link register pointing
back to an error path within the makecontext routine. This is currently
covered by the CFI FDE for makecontext itself, which is simply wrong
for the stack frame *inside* the context. When trying to unwind (e.g.
doing a backtrace) in a routine inside a context created by makecontext,
this can lead to uninitialized stack slots being accessed, causing the
unwinder to crash in the worst case.
Similarly, during parts of the "setcontext" routine, when the stack
pointer has already been switched to point to the new context, the
address range is still covered by the CFI FDE for setcontext. When
trying to unwind in that situation (e.g. backtrace from an async
signal handler for profiling), it is again possible that the unwinder
crashes.
Theses are all problems in existing code, but the changes in stack
frame layout appear to make the "worst case" much more likely in
the ELFv2 ABI context. This causes regressions e.g. in the libgo
testsuite on ELFv2.
This patch fixes this by ending the makecontext/setcontext FDEs
before those problematic parts of the assembler, similar to what
is already done on other platforms. This fixes the libgo
regression on ELFv2.
Aurelien Jarno [Tue, 3 Dec 2013 10:16:16 +0000 (11:16 +0100)]
locale: don't crash if locale-archive contains all zeros
In case of power failure followed by filesystem issues locale-archive
can end-up containing all zeros. In that case all calls to setlocale()
generate a SIGFPE. This renders a system with a default non-C locale
unbootable.
Avoid this by ignoring the locale instead of generating a SIGFPE.
[BZ #16195] Fix build warnings from systemtap probes in non-systemtap configurations
Joseph pointed out in the bug report (and in an earlier thread) that
systemtap probes cause build time warnings like the following:
../sysdeps/ieee754/dbl-64/e_atan2.c:602:4: warning: the address of
'p' will always evaluate as 'true' [-Waddress]
due to the fact that we're now passing non-weak variables to
LIBC_PROBE in the libm probes. This happens only on configurations
that do not enable systemtap. The macro definition of LIBC_PROBE in
this case only acts as a sanity checker to ensure that the number
parameters passed to LIBC_PROBE is equal to the argument count
parameter passed before it. This can be done in a much simpler manner
by just adding a macro definition for each number of arguments. I am
assuming here that we don't really want to bother with supporting
LIBC_PROBE with an indeterminate number of arguments and if there is a
need for a probe to have more data than what is currently supported (4
arguments), one could simply add an additional macro here.
Pavel Simerda [Mon, 2 Dec 2013 14:53:13 +0000 (20:23 +0530)]
Remove redundant GAIH_OKIFUNSPEC and GAIH_EAI.
Only gaih_inet() and gaih_inet_serv() use a special bit flag denoted
by the GAIH_OKIFUNSPEC macro. Only the return value of
gaih_inet_serv() is actively checked for the bit flag which is
redundant because it just copies the nonzero property of the value
otherwise returned. The return value of gaih_inet() is only checked
for being zero and then the bit flag is filtered out. As the bit flag
is set only for otherwise nonzero return values, it doesn't affect the
zero comparison. GAIH_EAI just an alias to ~GAIH_OKIFUNSPEC.
Get canonical name in getaddrinfo from hosts file for AF_INET (fixes 16077)
AF_INET lookup in hosts file uses _nss_files_gethostbyname2_r, which
is not capable of returning a canonical name if it has found one.
This change adds _nss_files_gethostbyname3_r, which wraps around
_nss_files_gethostbyname2_r and then returns result.h_name as the
canonical name.
Aurelien Jarno [Wed, 27 Nov 2013 13:42:06 +0000 (14:42 +0100)]
MIPS: Fix RLIM64_INFINITY constant for O32 and N32 ABIs
Fix the RLIM64_INFINITY constant for O32 and N32 ABIs to match the
kernel one. Change the getrlimit64/setrlimit64 into old compat symbols,
and provide the Linux generic getrlimit64/setrlimit64 functions as
GLIBC_2_19 version.
Aurelien Jarno [Wed, 27 Nov 2013 13:42:06 +0000 (14:42 +0100)]
MIPS: Add wrappers to get/setrlimit64 to fix RLIM64_INFINITY constant
RLIM64_INFINITY was supposed to be a glibc convention rather than
anything seen by the kernel, but it ended being passed to the kernel
through the prlimit64 syscall. On O32 and N32 ABIs, we therefore
end-up with different values on the userland and kernel side:
* On the kernel side, the value is defined for all architectures as
include/uapi/linux/resource.h:
#define RLIM64_INFINITY (~0ULL)
* On the GNU libc side, the value is defined in
ports/sysdeps/unix/sysv/linux/mips/bits/resource.h:
For the O32 and N32 ABI:
# define RLIM64_INFINITY 0x7fffffffffffffffULL
and for the N64 ABI:
# define RLIM64_INFINITY 0xffffffffffffffffUL
This was not a problem until the prlimit64 syscall was wired in the
2.6.36 kernel. Given the GLIBC uses the prlimit64 syscall to implement
getrlimit64 and setrlimit64, pam_limits.so is setting the limits to
a very big value instead of infinity. As a normal user process can
later only decrease the value and not increase it, it will later get
and EPERM error when trying to set the value to infinity with setrlimit.
The GLIBC has this constant for more than 7 years, and as it is defined
in a header file, it means a lot of binaries are in the wild. This patch
fixes that by adding a wrapper to fix the value passed to or received
from the kernel, before or after calling the prlimit64 syscall.
Carlos O'Donell [Mon, 25 Nov 2013 19:57:42 +0000 (14:57 -0500)]
Fix typo in sys/ptrace.h.
The event code is PTRACE_EVENT_SECCOMP, not PTRAVE_EVENT_SECCOMP.
This patch fixes the V->C typo. There are no ABI issues since the
number remains the same for the code. Code using the old wrong
name will need to be updated.
PowerPC: Set/restore rounding mode only when needed
This patch helps some math functions performance by adding the libc_fexxx
variant of inline functions to handle both FPU round and exception set/restore
and by using them on the libc_fexxx_ctx functions. It is based on already coded
fexxx family functions for PPC with fpu.
Here is the summary of performance improvements due this patch (measured on a
POWER7 machine):
Meador Inge [Thu, 21 Nov 2013 21:57:37 +0000 (16:57 -0500)]
Use __glibc_block in public headers.
As detailed in PR11157, the use of '__block' is known to interfere
with keywords in some environments, such as the Clang -fblocks extension.
Recently a similar issue was raised concerning the use of '__unused'
and a '__glibc' prefix was proposed to create a glibc implementation
namespace for these sorts of issues [1]. This patches takes that
approach.
Guy Martin [Thu, 21 Nov 2013 18:23:16 +0000 (13:23 -0500)]
Don't use broken DL_AUTO_FUNCTION_ADDRESS()
On hppa and ia64, the macro DL_AUTO_FUNCTION_ADDRESS() uses the
variable fptr[2] in it's own scope.
The content of fptr[] is thus undefined right after the macro exits.
Newer gcc's (>= 4.7) reuse the stack space of this variable triggering
a segmentation fault in dl-init.c:69.
To fix this we rewrite the macros to make the call directly to init
and fini without needing to pass back a constructed function pointer.
Chung-Lin Tang [Wed, 20 Nov 2013 21:12:18 +0000 (16:12 -0500)]
linux-generic: fix alignment of struct stat/statfs for nios2
The hard alignment of 8 was appropriate for most platforms for
which 8-byte values are 8-byte aligned, but this is not true
for the nios2 platform, so only align to the alignment of the
8-byte type on the platform.
Remove the explicit alignment of struct statfs as it's redundant.
Chris Metcalf [Mon, 18 Nov 2013 18:27:09 +0000 (13:27 -0500)]
test-fpucw-ieee: Don't use _FPU_IEEE if not defined
Not all architectures define this value, and if they don't,
just let the test run the same as test-fpucw, with __fpu_control
set to _FPU_DEFAULT explicitly.
git://sourceware.org / glibc.git / log