Commit Graph

287447 Commits

Author SHA1 Message Date
H. Peter Anvin
e7084fd52e x32: Switch to a 64-bit clock_t
clock_t is used mainly to give the number of jiffies a certain process
has burned.  It is entirely feasible for a long-running process to
consume more than 2^32 jiffies especially in a multiprocess system.
As such, switch to a 64-bit clock_t for x32, just as we already
switched to a 64-bit time_t.

clock_t is only used in a handful of places, and as such it is really
not a very significant change.  The one that has the biggest impact is
in struct siginfo, but since the *size* of struct siginfo doesn't
change (it is padded to the hilt) it is fairly easy to make this a
localized change.

This also gets rid of sys_x32_times, however since this is a pretty
late change don't compactify the system call numbers; we can reuse
system call slot 521 next time we need an x32 system call.

Reported-by: Gregory M. Lueck <gregory.m.lueck@intel.com>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Cc: H. J. Lu <hjl.tools@gmail.com>
Link: http://lkml.kernel.org/r/1329696488-16970-1-git-send-email-hpa@zytor.com
2012-03-05 15:35:18 -08:00
H. Peter Anvin
a628b684d2 x32: Provide separate is_ia32_task() and is_x32_task() predicates
The is_compat_task() test is composed of two predicates already, so
make each of them available separately.

Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Cc: H. J. Lu <hjl.tools@gmail.com>
Link: http://lkml.kernel.org/r/1329696488-16970-1-git-send-email-hpa@zytor.com
2012-03-05 15:35:18 -08:00
H. Peter Anvin
b263b31e8a x86, mtrr: Use explicit sizing and padding for the 64-bit ioctls
Specify the data structures for the 64-bit ioctls with explicit sizing
and padding so that the x32 kernel will correctly use the 64-bit forms
of these ioctls.  Note that these ioctls are bogus in both forms on
both 32 and 64 bits; even on 64 bits the maximum MTRR size is only 44
bits long.

Note that nothing really is supposed to use these ioctls and that the
preferred interface is text strings on /proc/mtrr, or better yet,
nothing at all (use /sys/bus/pci/devices/*/resource*_wc for write
combining; that uses PAT not MTRRs.)

Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
Cc: H. J. Lu <hjl.tools@gmail.com>
Tested-by: Nitin A. Kamble <nitin.a.kamble@intel.com>
Link: http://lkml.kernel.org/n/tip-vwvnlu3hjmtkwvij4qxtm90l@git.kernel.org
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
2012-03-01 12:48:52 -08:00
Ingo Molnar
8bd69c2d5f x86/x32: Fix the binutils auto-detect
Fix:

 arch/x86/Makefile:96: *** recipe commences before first target.  Stop.

Cc: H. Peter Anvin <hpa@linux.intel.com>
Cc: H. J. Lu <hjl.tools@gmail.com>
Link: http://lkml.kernel.org/r/1329696488-16970-1-git-send-email-hpa@zytor.com
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2012-02-28 10:35:06 +01:00
H. Peter Anvin
0bf6276392 x32: Warn and disable rather than error if binutils too old
If X32 is enabled in .config, but the binutils can't build it, issue a
warning and disable the feature rather than erroring out.

In order to support this, have CONFIG_X86_X32 be the option set in
Kconfig, and CONFIG_X86_X32_ABI be the option set by the Makefile when
it is enabled and binutils has been found to be functional.

Requested-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
Cc: H. J. Lu <hjl.tools@gmail.com>
Link: http://lkml.kernel.org/r/1329696488-16970-1-git-send-email-hpa@zytor.com
2012-02-27 14:09:10 -08:00
H. Peter Anvin
e0a449cab5 Merge branch 'core/types' into x86/x32 2012-02-25 21:57:26 -08:00
Bobby Powers
00194b2e84 x32: Only clear TIF_X32 flag once
Commits bb212724 and d1a797f3 both added a call to
clear_thread_flag(TIF_X32) under set_personality_64bit() - only one is
needed.

Signed-off-by: Bobby Powers <bobbypowers@gmail.com>
Link: http://lkml.kernel.org/r/1330228774-24223-1-git-send-email-bobbypowers@gmail.com
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
2012-02-25 20:42:23 -08:00
Bobby Powers
ce5f7a99df x32: Make sure TS_COMPAT is cleared for x32 tasks
If a process has a non-x32 ia32 personality and changes to x32, the
process would keep its TS_COMPAT flag. x32 uses the presence of the
x32 flag on a syscall to determine compat status, so make sure
TS_COMPAT is cleared.

Signed-off-by: Bobby Powers <bobbypowers@gmail.com>
Link: http://lkml.kernel.org/r/1330230338-25077-1-git-send-email-bobbypowers@gmail.com
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
2012-02-25 20:42:18 -08:00
David Howells
189017c25c fs: Remove missed ->fds_bits from cessation use of fd_set structs internally
Stephen Rothwell reported that the following commit broke the
linux-next build:

  1fd36adcd9: Replace the fd_sets in struct fdtable with an array of unsigned longs

Fix places where ->fds_bits needed to be removed as the core
kernel no longer uses fd_set internally for file descriptor
table management.  There are two places:

 (1) drivers/staging/android/binder.c

 (2) arch/mips/kernel/kspd.c

     Question: Should sp_cleanup() in the MIPS arch be using find_next_bit()
     or fls()?

Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: David Howells <dhowells@redhat.com>
cc: Ralf Bächle <ralf@linux-mips.org>
cc: Arve Hjønnevåg <arve@android.com>
Link: http://lkml.kernel.org/r/20120224105707.32170.11550.stgit@warthog.procyon.org.uk
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2012-02-24 14:04:50 +01:00
H. Peter Anvin
3f21723079 Merge branch 'core/types' into x86/x32 2012-02-23 18:35:25 -08:00
Bobby Powers
f044db4cb4 fs: Fix close_on_exec pointer in alloc_fdtable
alloc_fdtable allocates space for the open_fds and close_on_exec
bitfields together, as 2 * nr / BITS_PER_BYTE.  close_on_exec needs to
point to open_fds + nr / BITS_PER_BYTE, not open_fds + nr /
BITS_PER_LONG, as introducted in 1fd36adc: Replace the fd_sets in
struct fdtable with an array of unsigned longs.

Signed-off-by: Bobby Powers <bobbypowers@gmail.com>
Link: http://lkml.kernel.org/r/1329888587-3087-1-git-send-email-bobbypowers@gmail.com
Acked-by: David Howells <dhowells@redhat.com>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
2012-02-23 18:28:52 -08:00
H. Peter Anvin
862ae3132d x32: Drop non-__vdso weak symbols from the x32 VDSO
Drop the legacy weak symbols that don't carry the __vdso prefix from
the x32 VDSO.  This is a new ABI and we don't need to support that
legacy; the actual libc will export the proper symbols.

Suggested-by: Andy Lutomirski <luto@mit.edu>
Link: http://lkml.kernel.org/r/4F42E171.9080005@mit.edu
Cc: H. J. Lu <hjl.tools@gmail.com>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
2012-02-22 20:40:07 -08:00
H. Peter Anvin
22e842d4d9 x32: Fix coding style violations in the x32 VDSO code
Move the prototype for x32_setup_additional_pages() to a header file,
and adjust the coding style to match standard.

Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
Cc: H. J. Lu <hjl.tools@gmail.com>
2012-02-21 14:32:19 -08:00
H. J. Lu
1a21d4e095 x32: Add x32 VDSO support
Add support for the x32 VDSO.  The x32 VDSO takes advantage of the
similarity between the x86-64 and the x32 ABIs to contain the same
content, only the container is different, as the x32 VDSO obviously is
an x32 shared object.

Signed-off-by: H. Peter Anvin <hpa@zytor.com>
2012-02-20 12:52:06 -08:00
H. J. Lu
5fd92e65a6 x32: Allow x32 to be configured
At this point, one should be able to build an x32 kernel.

Note that for now we depend on CONFIG_IA32_EMULATION.  Long term, x32
and IA32 should be detangled.

Signed-off-by: H. Peter Anvin <hpa@zytor.com>
2012-02-20 12:52:06 -08:00
H. Peter Anvin
a06c9bc064 x32: If configured, add x32 system calls to system call tables
If CONFIG_X86_X32_ABI is defined, add the x32 system calls to the
system call tables.

Signed-off-by: H. Peter Anvin <hpa@zytor.com>
2012-02-20 12:52:06 -08:00
H. Peter Anvin
d1a797f388 x32: Handle process creation
Allow an x32 process to be started.

Originally-by: H. J. Lu <hjl.tools@gmail.com>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
2012-02-20 12:52:05 -08:00
H. Peter Anvin
c5a373942b x32: Signal-related system calls
x32 uses the 64-bit signal frame format, obviously, but there are some
structures which mixes that with pointers or sizeof(long) types, as
such we have to create a handful of system calls specific to x32.  By
and large these are a mixture of the 64-bit and the compat system
calls.

Originally-by: H. J. Lu <hjl.tools@gmail.com>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
2012-02-20 12:52:05 -08:00
H. Peter Anvin
a96d692e9a x86: Add #ifdef CONFIG_COMPAT to <asm/sys_ia32.h>
Unfortunately a lot of the compat types are guarded with CONFIG_COMPAT
or the equivalent, so add a similar guard to <asm/sys_ia32.h> to avoid
compilation failures when CONFIG_COMPAT=n.

Signed-off-by: H. Peter Anvin <hpa@zytor.com>
2012-02-20 12:52:05 -08:00
H. Peter Anvin
fca460f95e x32: Handle the x32 system call flag
x32 shares most system calls with x86-64, but unfortunately some
subsystem (the input subsystem is the chief offender) which require
is_compat() when operating with a 32-bit userspace.  The input system
actually has text files in sysfs whose meaning is dependent on
sizeof(long) in userspace!

We could solve this by having two completely disjoint system call
tables; requiring that each system call be duplicated.  This patch
takes a different approach: we add a flag to the system call number;
this flag doesn't affect the system call dispatch but requests compat
treatment from affected subsystems for the duration of the system call.

The change of cmpq to cmpl is safe since it immediately follows the
and.

Signed-off-by: H. Peter Anvin <hpa@zytor.com>
2012-02-20 12:52:05 -08:00
H. Peter Anvin
9d3897630e x32: Add rt_sigframe_x32
Add rt_sigframe_x32 to <asm/sigframe.h>.  Unfortunately we can't just
define all the data structures unconditionally, due to the #ifdef
CONFIG_COMPAT in <linux/compat.h> and its trickle-down effects, hence
the #ifdef mess.

Signed-off-by: H. Peter Anvin <hpa@zytor.com>
2012-02-20 12:52:05 -08:00
H. J. Lu
4048e2a8d4 x32: Add struct ucontext_x32
Add a definition for struct ucontext_x32; this is inherently a mix of
the 32- and 64-bit versions.

Signed-off-by: H. Peter Anvin <hpa@zytor.com>
2012-02-20 12:52:04 -08:00
H. Peter Anvin
851394229e x32: Export setup/restore_sigcontext from signal.c
Export setup_sigcontext() and restore_sigcontext() from signal.c, so
we can use the 64-bit versions verbatim for x32.

Signed-off-by: H. Peter Anvin <hpa@zytor.com>
2012-02-20 12:52:04 -08:00
H. Peter Anvin
f28f0c2357 x86: Move some signal-handling definitions to a common header
There are some definitions which are duplicated between
kernel/signal.c and ia32/ia32_signal.c; move them to a common header
file.

Rather than adding stuff to existing header files which contain data
structures, create a new header file; hence the slightly odd name
("all the good ones were taken.")

Note: nothing relied on signal_fault() being defined in
<asm/ptrace.h>.

Signed-off-by: H. Peter Anvin <hpa@zytor.com>
2012-02-20 12:52:04 -08:00
H. Peter Anvin
ea499fec48 x32: Generate <asm/unistd_64_x32.h>
Generate macros for the *kernel* code to use to refer to x32 system
calls.  These have an __NR_x32_ prefix and do not include
__X32_SYSCALL_BIT.

Signed-off-by: H. Peter Anvin <hpa@zytor.com>
2012-02-20 12:52:04 -08:00
H. Peter Anvin
6cbb369f57 x32: Generate <asm/unistd_x32.h>
Generate <asm/unistd_x32.h>; this exports x32 system call numbers to
user space.

[ v2: Enclose all arguments to syshdr in '' so empty arguments aren't
      dropped on the floor. ]

Signed-off-by: H. Peter Anvin <hpa@zytor.com>
2012-02-20 12:51:00 -08:00
H. Peter Anvin
6630f11ba5 x32: Add x32 system calls to syscall/syscall_64.tbl
Split the 64-bit system calls into "64" (64-bit only) and "common"
(64-bit or x32) and add the x32 system call numbers.

Signed-off-by: H. Peter Anvin <hpa@zytor.com>
2012-02-20 12:48:49 -08:00
H. Peter Anvin
2c73ce7346 x86-64, ia32: Drop sys32_rt_sigprocmask
On x86, the only difference between sys_rt_sigprocmask and
sys32_rt_sigprocmask is the alignment of the data structures.
However, x86 allows data accesses with arbitrary alignment, and
therefore there is no reason for this code to be different.

Reported-by: Gregory M. Lueck <gregory.m.lueck@intel.com>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
2012-02-20 12:48:49 -08:00
H. Peter Anvin
bb2127240c x32: Add a thread flag for x32 processes
An x32 process is *almost* the same thing as a 64-bit process with a
32-bit address limit, but there are a few minor differences -- in
particular core dumps are 32 bits and signal handling is different.

Signed-off-by: H. Peter Anvin <hpa@zytor.com>
2012-02-20 12:48:49 -08:00
H. J. Lu
d046ff8b30 x86-64: Add prototype for old_rsp to a header file
So far this has only been used in process_64.c, but the x32 code will
need it in additional code.

Signed-off-by: H. Peter Anvin <hpa@zytor.com>
2012-02-20 12:48:48 -08:00
H. J. Lu
0953f65d5d elf: Allow core dump-related fields to be overridden
Allow some core dump-related fields to be overridden.  This allows
core dumps to work correctly for x32.

Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Roland McGrath <roland@redhat.com>
Cc: Oleg Nesterov <oleg@redhat.com>
2012-02-20 12:48:48 -08:00
H. J. Lu
4ee5c0d05c compat: Create compat_sys_p{read,write}v64
For 32-bit ABIs which have real 64-bit registers, we don't want to
break the position argument into two.  However, we still need compat
support to deal with 32-bit pointers, so we can't just use
sys_p{read,write} directly.

Signed-off-by: H. Peter Anvin <hpa@zytor.com>
2012-02-20 12:48:48 -08:00
H. Peter Anvin
ff88943a14 aio: Use __kernel_ulong_t to define aio_context_t
Rather than using "unsigned long" which is ABI-dependent, use
__kernel_ulong_t to define the externally visible type aio_context_t.

Note: the change in this form will cause unsigned long/unsigned int
differences on existing ABIs.  If that is unacceptable we may have to
define a new type.

Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Cc: Benjamin LaHaise <bcrl@kvack.org>
2012-02-20 12:48:48 -08:00
H. Peter Anvin
644595f896 compat: Handle COMPAT_USE_64BIT_TIME in net/socket.c
Use helper functions aware of COMPAT_USE_64BIT_TIME to write struct
timeval and struct timespec to userspace in net/socket.c.

Signed-off-by: H. Peter Anvin <hpa@zytor.com>
2012-02-20 12:48:48 -08:00
H. J. Lu
ee4fa23c4b compat: Use COMPAT_USE_64BIT_TIME in net/compat.c
Handle 64-bit time structures in the networking core compat code.

Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Cc: David S. Miller <davem@davemloft.net>
2012-02-20 12:48:48 -08:00
H. J. Lu
da88cea120 compat: Use COMPAT_USE_64BIT_TIME in the Bluetooth subsystem
Enable the Bluetooth subsystem to be used with a compat ABI with
64-bit time.

Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Cc: Marcel Holtmann <marcel@holtmann.org>
Cc: Gustavo F. Padovan <padovan@profusion.mobi>
Cc: David S. Miller <davem@davemloft.net>
2012-02-20 12:48:47 -08:00
H. J. Lu
f930a7a0f4 compat: Use COMPAT_USE_64BIT_TIME in the input subsystem
Enable the input system to be used with a compat ABI with 64-bit time.

Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Cc: Dmitry Torokhov <dmitry.torokhov@gmail.com>
2012-02-20 12:48:47 -08:00
H. Peter Anvin
9dd4ccaaf8 compat: Handle COMPAT_USE_64BIT_TIME in the lp driver
Enable the lp driver to be used with a compat ABI with 64-bit time.

Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Greg Kroah-Hartman <greg@kroah.com>
2012-02-20 12:48:47 -08:00
H. Peter Anvin
6684ba202b compat: Add helper functions to read/write struct timeval, timespec
Add helper functions to read and write struct timeval and struct
timespec from userspace.  We already had helper functions for reading
and writing struct compat_timespec; add a set of functions to do the
same with struct timeval, and add a second suite of functions which
can be sensitive to COMPAT_USE_64BIT_TIME and access either 32- or
64-bit time structures.

This also exports these helper functions to modules.

Rename the existing inlines for converting between struct
compat_timeval and native struct timespec so we can have a saner
naming convention for the exported functions.

Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
2012-02-20 12:48:47 -08:00
H. J. Lu
45e8778129 compat: Introduce COMPAT_USE_64BIT_TIME
Allow a compatibility ABI to use a 64-bit time_t and 64-bit members in
struct timeval and struct timespec to avoid the Y2038 problem.

This will be used for the x32 ABI.

Signed-off-by: H. Peter Anvin <hpa@zytor.com>
2012-02-20 12:48:47 -08:00
H. Peter Anvin
109a1f32d0 sysinfo: Use explicit types in <linux/sysinfo.h>
Change <linux/sysinfo.h> to use explicitly sized types.  Replace
long/unsigned long with __kernel_[u]long_t so that a non-legacy 32-bit
ABI running on a 64-bit kernel can export those as 64-bit types.

Originally-by: H. J. Lu <hjl.tools@gmail.com>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
2012-02-20 12:48:47 -08:00
H. Peter Anvin
1f5e27a90a x32: Create posix_types_x32.h
This is the same as the 64-bit posix_types.h, except that
__kernel_[u]long_t is defined to be [unsigned] long long and therefore
64 bits.

Signed-off-by: H. Peter Anvin <hpa@zytor.com>
2012-02-20 12:48:47 -08:00
H. Peter Anvin
afead38d01 posix_types: Introduce __kernel_[u]long_t
Introduce __kernel_[u]long_t, which allows an ABI to override all
defaults of type [unsigned] long.

This enables x32 and potentially other 32-bit userspace on 64-bit
kernel ABIs.

Signed-off-by: H. Peter Anvin <hpa@zytor.com>
2012-02-20 12:48:47 -08:00
H. Peter Anvin
d8e5ddef21 sysinfo: Move struct sysinfo to a separate header file
struct sysinfo is just about the only thing exported to userspace from
<linux/kernel.h>, so move it into a separate header file with a
residual #include in <linux/kernel.h>.

Originally-by: H. J. Lu <hjl.tools@gmail.com>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Link: http://lkml.kernel.org/n/tip-4pr1xnnksprt7t0h3w5fw4rv@git.kernel.org
2012-02-20 12:48:46 -08:00
H. Peter Anvin
4f72e331c2 x86-64: Use explicit sizes in sigcontext.h, prepare for x32
Use explicit sizes (__u64) instead of implicit sizes (unsigned long)
in the definition for sigcontext.h; this will allow this structure to
be shared between the x86-64 native ABI and the x32 ABI.

Originally-by: H. J. Lu <hjl.tools@gmail.com>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Link: http://lkml.kernel.org/n/tip-4pr1xnnksprt7t0h3w5fw4rv@git.kernel.org
2012-02-20 12:48:46 -08:00
H. Peter Anvin
6bd330083e x86: Factor out TIF_IA32 from 32-bit address space
Factor out IA32 (compatibility instruction set) from 32-bit address
space in the thread_info flags; this is a precondition patch for x32
support.

Originally-by: H. J. Lu <hjl.tools@gmail.com>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Link: http://lkml.kernel.org/n/tip-4pr1xnnksprt7t0h3w5fw4rv@git.kernel.org
2012-02-20 12:48:46 -08:00
David Howells
cf420048b3 Delete the __FD_*() funcs for operating on fd_set from linux/time.h
Delete the __FD_*() functions for operating on fd_set structs from
linux/time.h as they're no longer used within the kernel with the preceding
patch and are not exported to userspace.

Whilst linux/time.h *does* export the FD_*() equivalents as wrappers around
__FD_*(), userspace provides its own definition of __FD_*().

Note that the definition of FD_ZERO() in linux/time.h may not be used with the
fd_sets associated with struct fdtable as the fd_set may have been allocated in
a truncated fashion.

Signed-off-by: David Howells <dhowells@redhat.com>
Link: http://lkml.kernel.org/r/20120216175006.23314.18984.stgit@warthog.procyon.org.uk
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
2012-02-19 10:32:28 -08:00
David Howells
1fd36adcd9 Replace the fd_sets in struct fdtable with an array of unsigned longs
Replace the fd_sets in struct fdtable with an array of unsigned longs and then
use the standard non-atomic bit operations rather than the FD_* macros.

This:

 (1) Removes the abuses of struct fd_set:

     (a) Since we don't want to allocate a full fd_set the vast majority of the
     	 time, we actually, in effect, just allocate a just-big-enough array of
     	 unsigned longs and cast it to an fd_set type - so why bother with the
     	 fd_set at all?

     (b) Some places outside of the core fdtable handling code (such as
     	 SELinux) want to look inside the array of unsigned longs hidden inside
     	 the fd_set struct for more efficient iteration over the entire set.

 (2) Eliminates the use of FD_*() macros in the kernel completely.

 (3) Permits the __FD_*() macros to be deleted entirely where not exposed to
     userspace.

Signed-off-by: David Howells <dhowells@redhat.com>
Link: http://lkml.kernel.org/r/20120216174954.23314.48147.stgit@warthog.procyon.org.uk
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
2012-02-19 10:30:57 -08:00
David Howells
1dce27c5aa Wrap accesses to the fd_sets in struct fdtable
Wrap accesses to the fd_sets in struct fdtable (for recording open files and
close-on-exec flags) so that we can move away from using fd_sets since we
abuse the fd_set structs by not allocating the full-sized structure under
normal circumstances and by non-core code looking at the internals of the
fd_sets.

The first abuse means that use of FD_ZERO() on these fd_sets is not permitted,
since that cannot be told about their abnormal lengths.

This introduces six wrapper functions for setting, clearing and testing
close-on-exec flags and fd-is-open flags:

	void __set_close_on_exec(int fd, struct fdtable *fdt);
	void __clear_close_on_exec(int fd, struct fdtable *fdt);
	bool close_on_exec(int fd, const struct fdtable *fdt);
	void __set_open_fd(int fd, struct fdtable *fdt);
	void __clear_open_fd(int fd, struct fdtable *fdt);
	bool fd_is_open(int fd, const struct fdtable *fdt);

Note that I've prepended '__' to the names of the set/clear functions because
they require the caller to hold a lock to use them.

Note also that I haven't added wrappers for looking behind the scenes at the
the array.  Possibly that should exist too.

Signed-off-by: David Howells <dhowells@redhat.com>
Link: http://lkml.kernel.org/r/20120216174942.23314.1364.stgit@warthog.procyon.org.uk
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
2012-02-19 10:30:52 -08:00
H. Peter Anvin
8b3d1cda4f posix_types: Remove fd_set macros
<asm/posix_types.h> includes a set of macros that operate on file
descriptors.  Way long ago those were exported to user space, but
nowadays they are #ifdef __KERNEL__.

However, they are nothing but standard (nonatomic) bit operations, and
we already have optimized versions of bit operations in the kernel.
We can't include <linux/bitops.h> in <asm/posix_types.h> but we can
move the definitions to <linux/time.h> and define them there in terms
of standard kernel bitops.

[ v2: folds the following fixes in:

  a) Stray space in __FD_SET(), reported by Andrew Morton
  b) #include <linux/string.h> needed for memset(), reported by Tony Luck ]

Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Link: http://lkml.kernel.org/r/1328677745-20121-22-git-send-email-hpa@zytor.com
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
2012-02-14 12:47:21 -08:00