linux-stable.git/arch/sparc/kernel/process_64.c, branch linux-3.9.y

flagday: kill pt_regs argument of do_fork()

2012-11-29T05:01:08+00:00

Signed-off-by: Al Viro

flagday: don't pass regs to copy_thread()

2012-11-29T04:43:42+00:00

Signed-off-by: Al Viro

Merge commit '517ffce4e1a03aea979fe3a18a3dd1761a24fafb' into arch-sparc

2012-11-17T01:49:06+00:00

Backmerge from the point in mainline where a trivial conflict had been
introduced (arch/sparc/kernel/sys_sparc_64.c had grown sys_kern_features()
right after where kernel_execve() used to be)

Signed-off-by: Al Viro

sparc64: Make montmul/montsqr/mpmul usable in 32-bit threads.

2012-10-26T22:18:37+00:00

The Montgomery Multiply, Montgomery Square, and Multiple-Precision
Multiply instructions work by loading a combination of the floating
point and multiple register windows worth of integer registers
with the inputs.

These values are 64-bit.  But for 32-bit userland processes we only
save the low 32-bits of each integer register during a register spill.
This is because the register window save area is in the user stack and
has a fixed layout.

Therefore, the only way to use these instruction in 32-bit mode is to
perform the following sequence:

1) Load the top-32bits of a choosen integer register with a sentinel,
   say "-1".  This will be in the outer-most register window.

   The idea is that we're trying to see if the outer-most register
   window gets spilled, and thus the 64-bit values were truncated.

2) Load all the inputs for the montmul/montsqr/mpmul instruction,
   down to the inner-most register window.

3) Execute the opcode.

4) Traverse back up to the outer-most register window.

5) Check the sentinel, if it's still "-1" store the results.
   Otherwise retry the entire sequence.

This retry is extremely troublesome.  If you're just unlucky and an
interrupt or other trap happens, it'll push that outer-most window to
the stack and clear the sentinel when we restore it.

We could retry forever and never make forward progress if interrupts
arrive at a fast enough rate (consider perf events as one example).
So we have do limited retries and fallback to software which is
extremely non-deterministic.

Luckily it's very straightforward to provide a mechanism to let
32-bit applications use a 64-bit stack.  Stacks in 64-bit mode are
biased by 2047 bytes, which means that the lowest bit is set in the
actual %sp register value.

So if we see bit zero set in a 32-bit application's stack we treat
it like a 64-bit stack.

Runtime detection of such a facility is tricky, and cumbersome at
best.  For example, just trying to use a biased stack and seeing if it
works is hard to recover from (the signal handler will need to use an
alt stack, plus something along the lines of longjmp).  Therefore, we
add a system call to report a bitmask of arch specific features like
this in a cheap and less hairy way.

With help from Andy Polyakov.

Signed-off-by: David S. Miller

sparc64: convert to generic execve

2012-10-16T23:03:12+00:00

We still have wrappers, but nowhere near as scary as they used to be.
I'm not sure how necessary that flushw is now, TBH...

Signed-off-by: Al Viro

sparc64: Add global PMU register dumping via sysrq.

2012-10-16T16:34:01+00:00

Signed-off-by: David S. Miller

sparc64: take fprs_write() and friends to start_thread()

2012-10-14T23:26:53+00:00

Signed-off-by: Al Viro

sparc64: switch to generic kernel_thread()

2012-10-14T23:26:52+00:00

Signed-off-by: Al Viro

sparc64: clear syscall_noerror on the entry to syscall, not on the exit

2012-10-14T23:26:52+00:00

Move that sucker to just before TI_FPDEPTH and replace stb with sth in
etrap_save().  Take current_ds to its old place, so that we don't push
wsaved into TI_... flags.  That allows to lose clearing syscall_noerror
on return from syscall.

Signed-off-by: Al Viro

vfs: define struct filename and have getname() return it

2012-10-13T00:14:55+00:00

getname() is intended to copy pathname strings from userspace into a
kernel buffer. The result is just a string in kernel space. It would
however be quite helpful to be able to attach some ancillary info to
the string.

For instance, we could attach some audit-related info to reduce the
amount of audit-related processing needed. When auditing is enabled,
we could also call getname() on the string more than once and not
need to recopy it from userspace.

This patchset converts the getname()/putname() interfaces to return
a struct instead of a string. For now, the struct just tracks the
string in kernel space and the original userland pointer for it.

Later, we'll add other information to the struct as it becomes
convenient.

Signed-off-by: Jeff Layton 
Signed-off-by: Al Viro