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

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>

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>

Stephen Rothwell reported that the following commit broke the
linux-next build:

  1fd36adc

: 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>

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>

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>

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>

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>

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>

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>

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>

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>

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>

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>

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>

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>

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>

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>

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>

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>

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>

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>

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>

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>

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>

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>

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>

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>

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>

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>

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>

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>

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>

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>

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>

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>

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>

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