X32 ptrace is a hybrid of 64bit ptrace and compat ptrace with 32bit
address and longs.  It use 64bit ptrace to access the full 64bit
registers.  PTRACE_PEEKUSR and PTRACE_POKEUSR are only allowed to access
segment and debug registers.  PTRACE_PEEKUSR returns the lower 32bits
and PTRACE_POKEUSR zero-extends 32bit value to 64bit.   It works since
the upper 32bits of segment and debug registers of x32 process are always
zero.  GDB only uses PTRACE_PEEKUSR and PTRACE_POKEUSR to access
segment and debug registers.

[ hpa: changed TIF_X32 test to use !is_ia32_task() instead, and moved
  the system call number to the now-unused 521 slot. ]
Signed-off-by: "H.J. Lu" <hjl.tools@gmail.com>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Cc: Roland McGrath <roland@hack.frob.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Link: http://lkml.kernel.org/r/1329696488-16970-1-git-send-email-hpa@zytor.com

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

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

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.orgSigned-off-by: H. Peter Anvin <hpa@zytor.com>

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.comSigned-off-by: Ingo Molnar <mingo@elte.hu>

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.comSigned-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.comSigned-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.ukSigned-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.comAcked-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>